Buckwheat Production and Value-Added Processing: A Review of Potential Western Washington Cropping and Food System Applications

Abstract

Increasing cropping system diversity can promote agricultural sustainability; however, identifying suitable alternative crops for regional growing conditions, supply chains, and markets is challenging. This review considers the potential for buckwheat production and consumption in western Washington (WWA). Buckwheat production is modest in WWA but is promising as a weed suppressive summer crop in organic systems and a short-season alternative to cereal grains. Key challenges for production in the region include flood sensitivity and sensitivity to heat at seed set, which should be breeding targets in WWA. Other production challenges include access to suitable production, storage, and transportation equipment. Regarding end-use qualities, buckwheat is composed of ash (1.1–3.1%), moisture (7.6–11.7%), crude fat (0.9–5.4%), crude fiber (0.8–10.6%), protein (6.8–17.9%), and starch (65.6–76.8%). Information about buckwheat fraction (starch and protein) functionality is limited. Buckwheat has been tested in an array of products, including pasta, noodles, cakes, cookies, bread, and beer. To enhance the quality of buckwheat food products, various enzymes and activation ingredients including transglutaminase, xanthan gum, and calcium hydroxide have been explored. Simultaneously addressing these research gaps for food products and crop production systems will be critical to successfully investing in and developing a regional supply chain in WWA.

1. Introduction

Increasing crop diversity can promote agricultural sustainability by improving the resilience of cropping systems to disturbance and providing more marketing opportunities for producers. However, over the past few decades, agricultural systems in the United States have tended to become more homogeneous [1]. Crop diversity can be reintroduced to agricultural ecosystems by cultivating alternative crops but it is often difficult to identify crops suited for specific regional growing conditions, supply chains, and markets. Common buckwheat (Fagopyrum esculentum) (CBW) has been identified as a promising crop for integration into food systems in western Washington (WWA). This review examines the opportunities, risks, and barriers to developing a regional CBW supply chain between WWA production systems and the food system they serve, including Seattle, WA, and Portland, OR. We aim to (i) synthesize information relevant to CBW production and potential product development, and (ii) provide working recommendations for farmers and food product developers experimenting with CBW in this region. We conclude by synthesizing the partnerships and infrastructure development that would connect farmers and food product developers in the region and identify future research that could strengthen the prospects for CBW as a crop in WWA.

1.1. Food System Approach

Introducing a novel crop requires troubleshooting for each facet of the supply chain in which that crop is being introduced, particularly for adoption into a regional food system. Details regarding crop production, post-harvest management and processing, product development, and distribution must be considered as each step is imperative to successful adoption. For example, the absence of infrastructure for post-harvest management (i.e., cleaning, drying, storage) and processing a novel crop can be detrimental to a supply chain. However, appropriate infrastructure cannot be established before a crop is proven viable to grow in a region and an intended end use has been determined. Crop production and end use are also mutually dependent as producers need end-use processors to financially support their crop production, and end-use processors need access to appropriate raw materials. For these reasons, the following review will explore the viability of CBW adoption in WWA and potential end uses relevant to the region.

1.2. Origin and Global Production

CBW is a summer annual pseudocereal belonging to the Polygonaceae or smartweed family. The crop is a feature of crop rotations across North America and Eurasia. Most recent evidence indicates that the center of origin and domestication of buckwheat is in southwestern China, based on amplified fragment length polymorphism analyses, the distribution of wild buckwheat relatives, and archeological evidence in ancient civilizations dating back as far as the Chunqiu dynasty 2500 years ago [2,3]. Buckwheat production then diffused to Japan via Korea and northern China and to the Karakoram and Hindukush ranges of Pakistan and Afghanistan via Bhutan, Nepal, and Kashmir [4]. Buckwheat is believed to have been transported to Europe through northern China via the Silk Road approximately 500 years ago [5]. Currently, 1.9 million ha of CBW are currently produced globally, approximately 5% of which is grown in North America [6].

Tartary buckwheat (Fagopyrum tataricum) (TBW) is the only other cultivated species of buckwheat in the world, though there is no known commercial production in North America. Unlike CBW, the geographic range of TBW is relatively narrow and is primarily produced near its center of origin in northern and southwestern China [7,8]. Despite its limited production range, there is substantial interest in TBW, particularly in the food product development literature, because it has elevated levels of rutin and other potential nutraceutical compounds compared to CBW [9]. We discuss TBW at points in this review where the CBW literature is limited, especially when characterizing the food functionality of buckwheat.

1.3. Buckwheat Production in Washington State

CBW was brought to the modern day United States during European colonization. The crop was grown widely and acreage peaked in the United States at 340,000 ha in the late 19th century and decreased precipitously at the turn of the 20th century (Figure 1). During this time period, farming operations consolidated, doubling in size on average [10]. The United States farming landscape simultaneously shifted to accommodate export markets. Farms became more homogenous (70% fewer crop types per farm) and United States exports grew eight-fold. In the process of this shift, buckwheat did not emerge as a top commodity in the 20th century agricultural landscape. Today, CBW production has remained between 65,000 and 84,000 ha since 2000, approximately 0.6% of United States wheat acreage [11]. It is most widely produced in North Dakota, Washington, and Minnesota [11]. In Washington State, CBW cultivation is concentrated in the arid central part of the state, primarily grown under irrigated conditions [12]. In this system, CBW is planted as a late summer double or stubble crop, often following small grains, grass seed, or hay. Virtually none of the CBW grown in this region is used domestically and instead is exported to Japan, which receives 92% of all United States CBW exports [13]. The capacity to have a highly controlled system with a predictable water supply and a low risk of precipitation after swathing makes this region well-suited for the meeting strict seed quality standards of the Japanese market.

There is also an opportunity to produce CBW in the temperate and high rainfall bioregions typical of WWA; however, WWA farms tend to be smaller and have higher in-season precipitation than those in central WA [15,16]. A rainfed system is inherently less controlled than one on a rigid irrigation schedule; therefore, we expect that buckwheat performance and quality will be more variable in the rainfed systems of WWA compared to central WA, making it difficult for WWA farms to compete in a highly standardized commodity market. Considering precipitation and farm size, production in WWA is better suited for small-scale regional markets than the commodity-focused export market typical in central WA. Additionally, there is a high prevalence of specialty seed crop producers and processors in the area, as well as producers who often integrate summer cover crops and rotational grains into their cropping systems, who are likely to have access to the equipment required for CBW production (Figure 2).

Finally, this region has a unique food system consisting of large metropolitan centers, such as Seattle, WA, and Portland, OR, that closely neighbor swaths of diverse and productive farmland. These cities boast a vibrant local food culture and currently serve as hubs for the direct marketing of food products that could provide a substantial market for specialty buckwheat products produced in the region [17]. Direct-to-consumer food sales from farms in Washington state amount to approximately $68.5 million annually [11]. Seattle alone supports a total of 15 farmers markets, through which hundreds of local farms market directly to consumers, and grains and flours are sold at 20% of Washington farmers markets [18]. The presence of metropolitan wealth and interest in local and artisan goods creates an opportunity for CBW to be viable in a variety of regional markets.

1.4. Market Potential

There are a variety of opportunities to integrate CBW into novel food products produced in WWA for regional and national distribution. Relevant applications of CBW include baked products such as crackers [19], cookies [20,21], biscuits [22], and bread [23]. Buckwheat flour (BF) has also been used in pasta [24,25,26], noodles [27,28], and expanded products [19,29]. Additionally, CBW can be malted and used as an ingredient in beer [30,31]. WWA has exceptionally high numbers of bakers, a rich diversity of international restaurants, and hundreds of breweries where CBW could be incorporated into this array of different products [32,33].

Buckwheat products are also being directed into the gluten-free (GF) market. People with autoimmune celiac disease must adhere to a strict GF diet to avoid and mitigate damage to the small intestine that leads to the malabsorption of nutrients [34,35]. However, while only about 1% of the US population suffers from celiac disease, approximately 6% of consumers reported non-celiac sensitivity to gluten [36], and approximately 20% of consumers reported “actively trying to include” GF foods in their diet [37]. Consumers who value other food production practices such as organic and “locally grown” were found to be about four times more likely to value GF food [37], indicating a rich market opportunity for CBW in WA state, which had the second highest organic sales in the country in 2019 [38].

Consumption of GF products, especially products that require flour from GF grains and pseudocereals, such as bread, pasta, and snacks, has increased dramatically and is expected to continue [36]. However, recent studies have also suggested that people who adhere to a GF diet may suffer from nutrient deficiencies such as vitamin B and fiber [39]. Researchers speculate this nutrient deficiency may result from many GF ingredient substitutes not being fortified with vitamins and minerals, or being primarily composed of starches [35]. Therefore, developers of GF foods are increasingly interested in buckwheat as a rich source of protein, dietary fiber, and antioxidants [40].

Additionally, buckwheat is promising for applications in functional food products. Functional foods are raw or processed and can provide positive health effects beyond those provided by basic nutrition when consumed regularly [41]. Buckwheat has been tested in various functional food products due to its nutritional composition and bioactive compounds [42]. This could be a lucrative marketing opportunity for CBW production in WWA, which neighbors high-earning metropolitan areas with access to health food vendors and natural grocers.

2. Crop Production

2.1. Washington State Cropping Systems

The existing cropping systems of WWA are diverse and provide multiple entry points for planting CBW. In other CBW production regions in the world, common previous crops include early spring or winter vegetables, winter grains, short season seed crops, or a failed spring or fall-sown crop [43,44,45,46]. In WWA, rotations are dominated by forages, corn silage, vegetables, barley, and wheat (Figure 2). In these systems, CBW would most likely be planted as a double crop following an early spring vegetable or early harvested winter crop. Because CBW is typically planted four to eight weeks later than spring grains, it would also be well-suited as a replacement or emergency crop in the case of a grain or forage crop failure in the spring. The prevalence of grain and forage production in WWA is promising for the availability of suitable equipment for CBW production in the region, including grain drills, combines, swathers, and pick-up headers, though not necessarily on the same farm. Many farmers in the region would need to borrow equipment or contract services from neighbors to adopt CBW as a cash crop in their system.

Figure 2. Growing area of popular crop types grown in counties in western Washington in 2017. Data source: [12].

Figure 2. Growing area of popular crop types grown in counties in western Washington in 2017. Data source: [12].

Though equipment may be a challenge for grain production, CBW is already a familiar summer cover crop in WWA, especially in organic systems that rely on integrated pest management for weed control and are interested in building soil organic matter. Despite its popularity for weed control, there are mixed reports on the efficacy of CBW as a weed suppressive summer cover crop. Several studies have found that CBW provides weed suppression comparable to or greater than summer grasses such as millet, sorghum, and sudangrass [47,48,49,50], but in cases where biomass production is poor, the weed suppressive ability is low compared to other spring and summer cover crops [51,52].

These reports underscore the importance of crop management to achieving weed-suppressive stands of CBW. Management decisions such as tillage method, the time between residue incorporation and seeding, and planting time can all impact the establishment of a CBW cover crop [53]. Abiotic stresses such as flooding and frost can impact stand establishment and are reviewed in the subsequent section of this paper.

Even highly productive CBW stands provide limited weed suppression following stand termination because residues decompose quickly due to their low carbon to nitrogen (N) ratio [47,54]. A metanalysis of the post-termination weed suppression of cover crops found that CBW does not provide effective weed control after termination, especially compared with grass cover crops with more persistent residues [55]. However, the allelopathic activity of fresh CBW root and shoot residues, exudates, and isolated tissue allelochemicals has been documented in a range of grass and broadleaf weed species indicating that living and recently terminated buckwheat stands can suppress weeds [54,56,57,58,59]. The allelopathic effects of fresh CBW biomass appear to diminish within two weeks following incorporation [58]. No studies have investigated the allelopathic effects of mature CBW biomass. The rapid decomposition of CBW biomass and its allelopathic activity indicates that producers should plan to use additional tools to manage fall weed pressure following CBW stand termination.

The N requirements of CBW make it well suited for cropping systems in WWA that receive organic inputs, including organic and animal-associated crop production. Fertilizer recommendations for N, phosphorus, and potassium are lower than cereal crops and make CBW well suited for lower fertility and low-input production systems [60,61,62]. Producers should limit N supply to CBW to avoid excessive vegetative growth and lodging. Increased lodging under high N supply is associated with excess vegetative growth and reduced stem lignin synthesis [63]. With the addition of N, plant height, as well as lodging incidence and severity, increases [63,64,65]. No North American CBW fertility recommendations suggest a N supply in excess of 45 kg N supply Mg-1 yield. There are no existing fertilizer recommendations for CBW production for Washington or elsewhere in the western United States.

Recent studies have indicated that N management can have a significant impact on the end use and nutritional quality of buckwheat seeds. Gao et al. [66] showed that high levels of N fertilization led to higher pasting temperatures and higher gelatinization enthalpy but lower final viscosities of starches. Another study by Wan et al. [67] showed that higher levels of N fertilization could lead to the upregulation of arginine, leucine, isoleucine, and valine biosynthesis. These studies demonstrate that management and environment can have a substantial impact on the end-use quality and nutritional composition of buckwheat. As this is an emerging area of study, more investigation into the magnitude of these effects across varieties and environments is needed to understand the suitable end uses of buckwheat sourced from a particular region or of a particular variety.

Several factors could limit the adoption of buckwheat in WWA cropping systems. First, volunteer management of CBW is a major concern for prospective CBW producers in WWA. This is especially true in systems with very low tolerance for contamination, such as wheat production for export. In wheat systems, buckwheat contamination is a concern because it is an allergen in Japan, South Korea, and China [68], which are some of the top importers of Washington wheat for use in specialty baked goods. Multiple herbicides are labelled and effective for CBW control in small grains, though control of CBW via chemical control is generally less effective in irrigated systems [69,70]. If producers have no tolerance for CBW volunteers in subsequent crops, cultural practices are needed to supplement chemical control. Lyon et al. [70] suggest several cultural strategies for managing volunteer CBW: (i) wait at least one year to grow wheat following CBW, (ii) use shallow tillage to stimulate rapid CBW germination, and (iii) reduce irrigation in combination with herbicide applications to reduce CBW recovery from herbicide damage.

Producers must also consider the influence of planting time on crop growth, development, and agronomic performance. CBW’s growth habit and phasic development are highly responsive to day length conditions. The response of three Japanese CBW accessions (‘Shinanonatsusoba’, ‘Miyazakizairai’, and ‘BLO 1999’) and one French variety (‘La Harpe’) to constant long-day and short-day conditions has been assessed [71,72,73]. Long-day conditions before anthesis have an especially pronounced effect on plant development, causing increased stem length, internode length, and a longer period to the onset of anthesis [72]. In a follow-up experiment, longer daylengths were associated with a longer period to the onset of anthesis, a longer period of stem elongation, and decreased seed number [71]. However, the strength of the treatment effects on development varied between summer and autumn ecotypes. Similarly, La Harpe has been characterized as a facultative short-day plant because the number of stem nodes before the first flower and days to flowering was reduced under short-day conditions [73].

A planting date trial conducted by Arduini et al. [74] found that exposure to declining day length extended growth phases. Moreover, when plants were exposed to declining day length only during the reproductive phase, or in both the vegetative and reproductive phases, the overall growth cycle was longer than plants grown with entirely increasing day length. However, regardless of the day length treatments in this study, the number of days to maturity for all planting dates ranged from 80 to 91 days, all still taking fewer than 12 weeks from planting to physiological maturity. These findings demonstrate that CBW growth cycles can be accelerated by planting in short or entirely decreasing day length conditions. They also demonstrate that a rapid growth cycle of three or fewer months is still possible, even with suboptimal planting dates. This short growing period would still permit a buckwheat crop to be grown sequentially with crops that are harvested in the early summer and planted in the early fall.

2.2. Abiotic Stresses within Western Washington

In North America, recommended CBW planting dates range from mid-May to late July or August [44,61,69]. Because heavy fall rains limit fall field activities in WWA, spring or early summer plantings are most suitable for the region. Planting in July or later would be risky in this region as fields become too waterlogged to operate in October and November. Therefore, the following discussion focuses on the potential stresses of spring or early summer-planted CBW.

The mild temperatures of WWA bode well for summer CBW cultivation because the crop’s reproductive structures are highly susceptible to heat stress. Heat protective mechanisms, including the synthesis of heat shock proteins, can be induced in flowers at temperatures of 30 °C [75]. High-temperature growing conditions (in excess of 30 °C) can drastically reduce seed set, seed weight, and overall yield [76]. This is because ovules are highly sensitive to temperature stress, even at 30 °C, whereas pollen viability is much less affected by heat stress, even at more extreme temperatures (40 °C) [77,78]. However, while 30 °C can induce stress in reproductive tissues, improvements in photosynthetic efficiency have been measured from 20 to 30 °C, indicating that the optimal temperatures for photosynthetic efficiency are substantially higher than the optimal temperatures for seed set [79].

Overall, it is rare for ambient temperatures in WWA to exceed 30 °C. For all WWA counties, average temperatures and average high temperatures remain far below 30 °C during the growing season (Figure 3). Even when we only look at the most extreme temperatures on record for at least the past five years, four WWA counties (Skagit, Pacific, Jefferson, and Grays Harbor) all have 50 or fewer calendar days where the highest temperature on record has exceeded 30 °C (Figure 4). There are other counties in the region with a higher likelihood of reaching temperatures that could damage CBW reproductive tissues. Clark, Skamania, Pierce, and King counties have more than 100 calendar days where the highest temperature on record exceeded 30 °C.

CBW is frost sensitive and is particularly prone to damage at early growth stages [81]. Therefore, CBW should be planted after the risk of last frost. In WWA, it is unlikely that fields will be ready to plant before the risk of last frost passes. Last frost dates across the region range from early April to early May (Figure 5). Assuming approximately 12 weeks are needed from crop planting to maturity, there is adequate time for CBW to mature if planted after the risk of last frost.

Flooding and saturated soils pose the most serious risk to CBW production in WWA. Heavy rains following planting can limit emergence and reduce crop yields by 40% compared to an average year [82]. Flooding at any stage can impact the growth and development of CBW, but early growth stages are particularly susceptible to flooding stress [83]. There is some evidence for genotype-dependent flooding resistance in CBW [84,85]. Murayama et al. [84] tested the germination rate of 32 CBW lines following submersion and found, on average, that germination reduced 53%, though some lines were reduced 90% and others were minimally affected. In an evaluation of flooding tolerance during the germination of 17 CBW lines, researchers identified four lines that maintained a 50% emergence rate following flooding stress [85]. This study also demonstrated that it is possible to improve the flooding tolerance of CBW by 10% after only four generations of mass selection under mild selection pressure. These findings are promising for the development of flooding-tolerant CBW varieties for WWA.

The cause of poor CBW emergence following flooding has been extensively studied in New York State [82]. Following a series of experiments, the authors concluded that a soil-borne pathogen, not anoxia or mechanical impedance, was the most likely cause of poor CBW stands following flooded conditions in the region. These results have yet to be replicated in other regions, nor has the potential for resistance to the effect of the pathogen in flooded soils been investigated.

In WWA, heavy rains and flooding can persist into May and even June (Figure 6), which overlaps with otherwise optimal planting times in the region. Flooded soils and their effect on CBW stands will become an emerging problem as the crop is further adopted in the region. The impact of flooded soils on buckwheat can be mitigated by using cultural practices, such as: (1) avoiding planting CBW if heavy rain is in the forecast, (2) prioritizing planting in fields or field areas that are well drained, and (3) preparing the soil adequately to encourage water to drain out of the seed bed. In the long term, the development of flooding-tolerant CBW lines would be advantageous to WWA production and limit production losses in high rainfall years.

2.3. Buckwheat Breeding for Western Washington

Several recent reviews have synthesized the state of the literature for breeding buckwheat for a range of targets, including improved end-use quality and seed composition [86], increased protein concentration and improved amino acid (AA) composition [87], cultivation in Japan for Japanese markets [88], and reduced bitterness [89]. Reviews have also synthesized efforts for breeding buckwheat across the globe and recommended strategies for applying modern breeding approaches such as hybrid breeding and genomic selection for crop improvement [90] as well as the potential to develop self-compatible CBW lines using marker-assisted selection [91].

Since 1974, 13 buckwheat varieties have been registered with the Canadian Food Inspection Agency or issued a Plant Variety Protection Certificate via the United States Department of Agriculture [92,93] (

Table 1. List of buckwheat varieties either registered with the Canadian Food Inspection Agency [92] or issued a Plant Variety Protection Certificate by the United States Department of Agriculture [93].

Variety	Year	Country	Submitted by	Issued Plant Breeder Rights or Plant Variety Protection Certificate
Mancan	1974	Canada	Agriculture and Agri-food Canada
Manor	1980	Canada	Agriculture and Agri-food Canada
Winsor Royal	1983	USA	Winsor Grain, Inc., Minnesota	Yes
AC Manisoba	1996	Canada	Agriculture and Agri-food Canada
AC Springfield	1997	Canada	Springfield Mills
Koban	1999	Canada	Agriculture and Agri-food Canada
Koto	2000	Canada	Agriculture and Agri-food Canada	Yes
Koma	2005	Canada	Kade Research	Yes
Horizon	2011	Canada	Mancan Genetics
Kenmar	2016	Canada	Springfield Mills
Takane Ruby 2011	2016	USA	Takano Co. Ltd., Japan	Yes
Aoi	2017	USA	McKay Seed Co. Inc., Washington	Yes
Agassiz	2019	Canada	Mancan Genetics

). Of the ten varieties registered in Canada, only two, ‘Koto’ and ‘Koma’, have been granted plant breeders rights. Koto has darker, rounder seeds, with higher test weight than the older varieties ‘Koban’ and ‘Mancan’. Koma was produced from a cross with F. homotropicum and, notably, has the capacity to both self pollinate and outcross.

Two varieties have active Plant Variety Protection certificates in the United States: ‘Takane Ruby 2011’ and ‘Aoi’. Takane Ruby 2011 was produced from a selection from the Japanese variety ‘Takane Ruby’ and has a deeper pink flower color. The most recent variety issued a Plant Variety Protection Certificate in the United States, ‘Aoi’, was developed from a cross between Koto and a self pollinating F. homitropicum line. This is also the first variety to be released in Washington State, though it was developed in the irrigated region in the central portion of the state. Aoi is self-pollinating and has a deeper green testa, which is a highly valued trait in Japan for making soba noodles.

Over the past 50 years, North American buckwheat varieties have been released with an improved test weight, larger seed size, novel coloration (flowers, testa, and hulls), and greater potential to self pollinate. The most recent variety released in the United States, Aoi, is an important advancement for existing Washington State buckwheat production and will enhance the quality of buckwheat production in this region for export to Japan. However, there still has been little advancement in developing varieties for WWA. Variety development and testing will need to identify varieties with exceptional agronomic performance and end-use quality for the production systems and target markets for this region. In addition to high seed yield and test weight, exceptional agronomic performance will include performance under rainfed conditions, flooding tolerance, early maturity, especially for areas where high levels of precipitation are common in the early fall, and heat tolerance for areas with a high incidence of temperatures over 30 °C.

3. Food Application

As the agronomic opportunities and challenges of growing CBW in WWA cropping systems become better understood, it is equally as important to understand the opportunities and challenges for integrating this crop into regionally processed food products. Here, studies on physiochemical characteristics, functional properties, fractions, and product development are reviewed to identify opportunities and challenges relevant to end-use processors who are integral in the successfully adopting of new products into a food system. Food science studies specific to CBW are limited, so studies on TBW have also been reviewed to provide supporting information regarding the characteristics of these related crops.

3.1. Physicochemical Characteristics of Buckwheat

3.1.1. Proximate Composition

The proximate composition of different buckwheat species and varieties have been reported [40,94,95,96,97]. A summary of the proximate composition and its comparison to whole wheat and white all-purpose, enriched, bleached wheat flour is provided in

Table 2. Proximate composition of common (C) and tartary (T) buckwheat.

	Bhinder et al. [94]	Tien et al. [97]	Khan et al. [95]	Lu et al. [96]	Qin et al. [40]	USDA Whole Wheat Flour [98]	USDA White All-Purpose, Enriched, Bleached Wheat Flour [98]
G/W 1	Unknown	G	G	G	Unknown	-	-
Number of varieties per species	T: 23	T: 1 C: 1 Tetraploid T: 1	C: 4	C: 9 T: 1	T: 21 C: 18	-	-
Growing location/seed source	National Bureau of Plant Genetic Resources (Shimla, India)	T Miyake Seifun Co., Ltd. (Osaka, Japan) C Nikkoku Flour Milling Co., Ltd. (Nagano, Japan) Tetraploid T University of Japan	Gilgit/Baltistan, Pakistan	Seed from McKay Seed Company (Almira, WA, USA) grown in Eastern WA, USA	China (Guizhou, Shanxi, Ningxia, Inner Mongolia, Hebei, Liaoning)	-	-
Moisture (%)	7.6–10.8	-	9.3–11.7	-	-	10.7	11.9
Ash (%)	1.8–2.8	T: 2.4 C: 2.2 Tetraploid T: 2.1	1.1–1.6	T: 1.8–2.1 C: 2.7	T: 1.9–3.1 C: 1.3–3.1	1.6	0.5
Crude fat (%)	2.0–3.6	T: 2.9 C: 2.4 Tetraploid T: 2.7	0.9–1.5	-	T: 1.2–4.7 C: 1.5–5.4	2.5	1.0
Crude fiber (%)	-	-	0.8–1.0	T: 3.6–7.6 C: 10.6	T: 1.7–4.0 C: 1.3–3.1	10.7	2.7
Protein (%)	9.1–14.9	T: 12.8 C: 13.3 Tetraploid T: 14.1	13.9–16.5	T: 10.4–13.4 C: 17.9	T: 6.8–15.0 C: 8.1–12.4	13.2	10.3
Starch (%)	66.3–72.5	-	-	T: 72.8–76.8 C: 61.2	T: 65.6–74.3 C: 65.9–78.1	72.0	76.3

¹ G = groats, W = whole flour.

. In many studies, the authors did not specify whether they analyzed whole or dehulled seeds, which is a research gap that should be further investigated.

Moisture content is influential on mold growth and lipid oxidation during the storage of flour [99,100]. Additionally, in rice and millet, thermal properties (thermal conductivity and diffusivity) increased when the moisture content increased [101,102]. This could also be the case with buckwheat. Thermal properties are important for designing optimal processing systems for food products, such as extrusion [101,103].

Ash content is the inorganic compounds or minerals in flour [104,105]. Ash is used for the nutritional labeling of food products; as it increases, the hygroscopicity of flour and powdered food increases by binding with the moisture in the air [104].

Crude fat in flour influences the flavor and mouthfeel of food [106]. However, flour with high crude fat values could be problematic for processing as the fat could cause issues with machinery, such as clogging the screens in milling equipment. Additionally, a formulation with a high fat content without any preservatives could have problems with lipid oxidation and rancidity [107].

Crude fiber content is composed of both insoluble and soluble fiber. Whole buckwheat flour has higher amounts of fiber than dehulled buckwheat flour due to the presence of the hulls [96]. Fibers compete for water with the other macromolecules present in the food matrix, such as protein and starch [108]. Therefore, the hydration levels in food formulations must be adjusted to account for more water absorption.

Protein influences the nutritional content of food products, as well as many functional properties such as emulsion stability and activity, foaming, and water and oil absorption [106,109,110]. Starch content and quality are influential on the pasting properties of the flour [111,112]. Additionally, the amylose/amylopectin ratio of starch is important to consider in food formulations.

As presented in Table 2, certain buckwheat varieties have a higher protein content than wheat flour, comparable levels of starch, and, in certain varieties, comparable fiber content to whole wheat flour. These macro nutrients play a significant role in product development and must be considered when developing food formulations.

3.1.2. Functional Properties

The functional properties of flour affect its processing characteristics and the quality of the food produced with it. Very few studies in the literature reported the functional properties of buckwheat (especially for CBW) and are summarized in

Table 3. Buckwheat flour functional properties.

	Bhinder et al. [94]	Raikos et al. [113]	Jan et al. [20]
C/T 1	T	Unknown	Unknown
WAC 2 (g/g)	2.3–2.7	1.4	1.3
OAC 3 (g/g)	0.9–1.4	-	1.7
ESI 4 (min)	35.5–77.8	76.1	-
EAI 5 (m2/g)	33.5–59.8	40.0	-
FC 6 (%)	10.3–23.7	85.0	31.7
FS 7 (%)	6.2–14.3	65.0	74.4

¹ C = common buckwheat, T = tartary buckwheat, ² WAC = water absorption capacity, ³ OAC = oil absorption capacity, ⁴ ESI = emulsion stability index, ⁵ EAI = emulsion absorption index, ⁶ FC = foaming capacity, ⁷ FS = foaming stability.

.

Table 4. Flour functionality and food application.

Functional Property	Ingredient Functionality	Food Application	References
WAC/WHC 1	Increase viscosity/thickening Moisture retention	Custards Soups Baked goods Meat products	[106,110,113]
OAC/OHC 2	Mouthfeel and texture flavor	Fried food (including battered/breaded food)	[106,109,114]
ESI and EAI 3	Support emulsion formation and resistance to change overtime	Salad dressing Mayonnaise Sausage Sauces Soups Ice cream Milk Butter Frozen desserts	[109,112,115,116]
FC and FS 4	Aeration Overrun	Baked goods Mousses Meringues Ice cream Whipped toppings	[94,113,117,118]
Pasting properties	Binding agent Thickening agent Gelling agent	Soup Sauces Asian noodles	[111,112,119,120,121]

¹ WAC = water absorption capacity, WHC = water holding capacity, ² OAC = oil absorption capacity, OHC = oil holding capacity ³ ESI = emulsion stability index, EAI = emulsion absorption index, ⁴ FC = foaming capacity, FS = foaming stability.

summarizes the ingredient functionality of these properties and suitable food applications.

Flours with a high water absorption capacity (WAC) increase the viscosity and thickness of foods and, thus, are suitable for custard and soup applications [113]. This quality also helps improve moisture retention and freshness in baked goods [110,113]. Oil absorption capacity (OAC) is important for fried food as it influences cooking yield [114]. Bhinder et al. [94] explained the variations in buckwheat OAC and WAC as affected by protein composition. Flours with high hydrophobic AA and non-polar side chains have good binding capacities to the fatty acid chains in oil. However, polar AA has a great affinity with water molecules.

Emulsions are vital for the stability of many foods such as sausages, sauces, and soups [110,122]. The emulsion activity index and emulsion stability index are characteristics related to the ability of proteins to support emulsion formation and resistance to change over time [94]. There are only a few studies about buckwheat flour with emulsion-related information.

Foaming capacity measures the ability of proteins to absorb air during whipping, while foaming stability determines the resistance of the material to droplet coalescence and liquid drainage [113]. These properties are important for aerated food systems such as mousses, meringues, baked goods, ice cream, and whipped creams [94,113,118]. The difference in whipping time and pH of the flour or water suspension could account for part of the variation across the three studies presented in Table 3.

Pasting properties exhibit the viscosity characteristics of starch in a water suspension with controlled heating and cooling [112,123]. These characteristics are influenced by starch granule rigidity, swelling, and amylose leaching [112]. Such information is useful when selecting flour to use as a binding, thickening, and gelling agent. Examples of food applications where pasting properties are important include soups [119], sauces [118], and Asian noodles [111].

Literature on the pasting properties of CBW whole flour is unavailable; however, a solitary study of TBW found that the peak viscosity of buckwheat varied between 336.3 cp and 2899.0 cp, the trough viscosity ranged from 333.5 cp to 1373 cp, and the final viscosity ranged from 619.8 cp to 2959.0 cp [94]. The breakdown viscosity varied from 3.3 cp to 1278.0 cp, the setback viscosity ranged from 184.0 cp to 1736.0 cp, and the pasting temperature varied from 60.7 °C to 73.8 °C [94]. The pasting properties indicate starch behavior in access water and shear with controlled heating and cooling [124]. Low breakdown and setback values indicate starch stability in high temperatures and shear force [94,111,125]. Such starches would be suitable as thickening agents in soups and sauces [94].

3.2. Buckwheat Fractions

Both protein and starch are components of buckwheat that have been studied individually. Each component has unique functional characteristics that can enable it to be used in specific food applications.

3.2.1. Protein

Most of the protein in buckwheat is in the aleurone layer and embryo of the seed [42]. Certain buckwheat varieties have levels of protein higher than wheat, rice, millet, and maize but lower than oats [42].

There is limited research on buckwheat protein fractionation, and the information available is inconclusive. An analysis of four protein fractions of Japanese CBW varieties showed that in three varieties lysine was the highest AA, followed by leucine [126]. Their protein fractions included, on average, albumins (20.99%); glutenins (13.31%); globulin (12.8%); and prolamin (4.35%). In an older study, Javornik and Kreft [127] reported that buckwheat protein fractions contained albumins (18.2%); (globulins 43.3%); prolamins (0.8%); and glutenins (22.7%). Guo and Yao [128] found the protein fraction of TBW contained, on average, albumins (43.8%); glutenins (14.6%); globulin (7.82%); and prolamin (0.5%).

Further research is needed to understand the buckwheat protein fractionation process and its commercialization potential within the food industry because the demand for plant-based protein ingredients is rising [129,130]. Issues around plant-based proteins include limited information about the functional properties of such components, commercial availability of the isolates, and differences in the flavor of those isolates [130]. Further research is needed to understand the buckwheat protein fractionation process and its commercialization potential within the food industry.

3.2.2. Starch

Starch is one of the main components of buckwheat [131]. Starch granules from different grain sources have a variety of shapes [132]. Wheat starch is lenticular and round [133,134], while buckwheat starch granules are mostly round and polygonal shaped. The buckwheat starch granule size ranges from 2 to 15 µm [133,135,136], and these dimensions are approximately 1.6–2.4 times smaller than wheat starch granules [132,133,134]. Small starch granules could be beneficial for the production of fat replacers due to their similar particle size to fat molecules [135].

Starch is composed of amylose and amylopectin, the ratio of which can affect the functional properties of starch [137,138]. The amylose content influences the solubility, pasting, and thermal properties of starch, all of which affect the quality of food products [135]. The amylose content of CBW ranges from 15.6% [131] to 46.6% [133,135,139,140]. In TBW, the amylose content ranges between 15.6% and 38.9% [131,135,140,141,142,143]. Although there is a variation in the amylose content between the two species, many CBW varieties have a similar amylose content to those of TBW, and buckwheat has a similar amylose content to wheat flour (22–35%) [138].

Buckwheat that has a high amylose content will demonstrate more retrogradation during hydrothermal processing than those with a lower amylose content [135]. Although a high amylose content increases retrogradation, it also causes the formation of resistant starch molecules, which encourages a slower digestion and other health benefits [144,145]. However, there is a lack of research on high amylose buckwheat varieties and their influence on the functional properties of flour and product development. This is a research gap that must be further investigated.

There have not been breeding efforts for buckwheat with high levels of amylopectin, which is a waxy starch. Waxy wheat has been shown to increase the water holding capacity and swelling, which increases the crumb softness and storage life in bread [144]. Partial waxy wheat starches (21–24% amylose) have been used to improve the quality of white salted noodles [145]. As seen in wheat, these benefits could possibly translate to waxy buckwheat varieties.

3.3. Product Development

3.3.1. Bread

Buckwheat flour (BF) has been tested in many baked good applications. The inclusion of BF in bread formulations (both GF formulations and gluten-containing formulations) changes the nutritional composition, influences quality attributes, and creates an opportunity for marketing as a functional food [141,146].

In previous studies, BF influenced bread quality in the following attributes: loaf-specific volume (LSV), crumb hardness, and moisture loss [23,147,148,149,150]. The studies found conflicting results. Wronkowska et al. [23] found that including up to 40% BF in GF bread increased the LSV and decreased the crumb hardness. Mariotti et al. [149] also showed an increase in LSV when 40% dehulled buckwheat was used. However, Torbica et al. [150] showed that both whole and dehulled BF flours increased bread hardness in GF bread. Therefore, there is a lack of consensus on the effects of buckwheat flour on crumb hardness.

In efforts to improve the functionality of buckwheat flour in bread formulations, especially in the absence of gluten, the addition of hydrocolloids and gums have been investigated [147,149]. There is no consensus on their benefits and drawbacks in the literature. Mariotti et al. [149] used a hydrocolloid, hydroxypropylmethylcellulose (HPMC), in GF bread and found the inclusion of 40% dehulled BF with 0.5% HPMC increased the LSV and decreased crumb hardness. When Hager and Arendt [147] included HPMC in their buckwheat GF bread formulations, they did not find an increase in the LSV but did show a reduction in crumb hardness. When xanthan gum was included in GF buckwheat bread formulations, LSV decreased and crumb hardness increased [147].

When BF was tested for bread quality in storage life studies, it had a lower moisture content and lower moisture loss than of white bread [148]. Torbica et al. [150] hypothesized that a decrease in the starch retrogradation of BF could lead to better anti-staling properties.

Wronkowska et al. [23] speculates that the water binding capacity (WBC) of buckwheat starch is influential on bread LSV. Buckwheat starch has a higher WBC than corn or wheat starch [23,151]. This leads to better dough development due to increased dough viscosity [149]. Additionally, the WBC of BF is hypothesized to increase the storage life of buckwheat bread [148]. When hydrocolloids are added to a GF BF bread formulation, it limits the interaction between starch and protein molecules, resulting in a softer bread. Mariotti et al. [149] and Torbica et al. [150] agreed that the starch quality, fiber content, and protein quality of BF influenced the bread quality [149,150].

3.3.2. Cookies

Numerous studies have been conducted on the performance of buckwheat in cookies and biscuits. An increased substitution ratio of BF flour to wheat flour results in a reduced spreading ratio [20,152,153]. This is potentially due to the BF flour aggregating with hydrophilic sites, in many cases protein, that compete with the free water available in the cookie dough [152,154,155,156].

In a study that substituted BF for wheat flour in cookies, Baljeet et al. [152] found both a decreased spreading ratio as the substitution levels increased, and an increase in cookie weight. The increase in cookie weight was explained by the ability of BF to retain oil during the baking process [152]. Yamsaengsung et al. [157] found a decrease in the spread ratio of GF formulations using BF and chickpea flour. Torbica et al. [150] characterized rice and buckwheat flours and tested their combinations for GF cookies. Although the starch granules of the three different flours were of different shapes and sizes, the GF cookies still had a cohesive structure and were comparable to wheat cookies when viewed under the microscope.

In sensory evaluations, cookies with up to 20% BF were acceptable to consumers [150,152]. This threshold is partially due to the bitter polyphenolic compounds in BF [150].

Transglutaminase (TG) is an enzyme that is used in GF baking to promote protein cross linking and mimic gluten [158]. When TG was used in a cookie with 100% BF flour, the spreading ratio increased when compared to a formulation without TG. These cookies were also softer and more brittle [158]. This enzyme could improve the functionality of BF in cookie formulations.

3.3.3. Cakes

Few studies have been conducted on the functionality of BF in cakes. Farzana et al. [159] substituted buckwheat flour for wheat flour in ratios of 10, 20, 30, and 40%. Cakes with 30% BF showed the highest score for sensory attributes. They also reported that since BF does not have any gluten, a weaker protein network was formed relative to the control, which was reflected in the uniformity of the cake. A study of the optimal baking conditions for GF buckwheat cakes determined that as the oven temperature increased, the moisture of the cake decreased, thereby increasing the hardness of the cakes [160]. The specific volume of buckwheat cake decreased with a higher oven temperature [160]. The higher oven temperature leads to a thicker crust which compresses the cake structure.

3.3.4. Pasta

Pasta is mainly made from semolina, a coarsely milled durum wheat which contains approximately 14% protein [161,162,163,164]. The unleavened pasta dough is shaped using either extrusion or lamination [164]. The raw material quality influences the cooking behavior of the final pasta [161]. Therefore, several researchers have studied the behavior of pure BF or a blend of BF with wheat flour or other GF cereal or pseudocereal flours for pasta production [24,25,26,162,165].

Pure CBW pasta requires less cooking time than wheat pasta. The absence of gluten in BF means it requires less water than gluten-containing flour, such as wheat, to be fully cooked [26].

Adding more than 30% CBW in durum wheat flour is associated with decreased dough strength. Gluten has an essential role in dough strength, and an increase in the ratio of CBW results in a decrease in the gluten content of the dough [165]. Additionally, increasing the CWB to more than 30% negatively impacted the color of the pasta due to the carotenoid pigments in the CBW flour [25]. A similar negative effect was also reported in pasta made from a blend of CBW flour, rice flour, and maize flour [24].

Xantham gum, propylene glycol alginate, and monoglyceride of fatty acid are different activation ingredients explored in various studies to improve buckwheat pasta quality [24,26,162]. Monoglyceride of fatty acid is a substance used to form a complex with amylose to limit amylose leaching in the cooking water and, consequently, ameliorate the quality and sensory characteristics of the CBW-containing pasta [24]. Adding 1% xanthan gum can boost adhesion between ingredients and increase the disintegration time of UBW (unspecified buckwheat)-containing pasta. Xanthan gum was also used as a stabilizing agent to compensate for the absence of gluten, which is required for dough consistency [162].

In addition to dry ingredients, the processing parameters, such as input moisture, barrel temperature, and screw speed, can also influence the quality of the pasta [25,26,166]. The optimal moisture content for CBW-containing pasta is 30%. Exceeding this level causes the dough to stiffen, resulting in sticky pasta that clings to the machine screw. As a consequence, the final product lacks textural firmness [25,26]. This finding is consistent with Wójtowicz’s [166] observation that an increased moisture content leads to a lower firmness in hydrated pasta. Higher moisture levels also decrease gelatinization and shearing force. This thereby produces a weaker and less durable final product with greater cooking loss. An optimum moisture content of 30% helps produce pasta with acceptable texture firmness and cooking quality.

Barrel temperature and screw speed in the extruder are other processing parameters that influence the final product. To produce a GF rice–CBW pasta, a barrel temperature of 120 °C and a screw speed of 80 rpm are suggested as optimum parameters [25]. The pasta produced under these conditions has a compact homogenous microstructure, low cooking loss (less than 6%), low stickiness, and acceptable hardness and firmness. In addition, high temperatures reduce starch melt viscosity and, thus, friction in the extruder. Thus, molecular degradation is limited, resulting in lower cooking loss [25].

Most of these studies on pasta made with UBW have focused on various raw materials and processing parameters. However, there is a lack of research on the functional properties of this flour and their relationship to the behavior of flour in processing, which merits further exploration. Additionally, flour bleaching, a common practice with wheat flour, is worthy of investigation to improve the pasta appearance of UBW and, thus, product acceptability.

3.3.5. Noodles

The main difference between noodles and pasta is the raw material used to make them and the shaping of the final product. Common wheat and rice flour are the two most common raw ingredients in noodles. Buckwheat noodles are also commonly consumed in northern China, Japan, Korea, and portions of Europe [167]. Noodles are shaped by sheeting and cutting [164].

The absence of gluten to provide shape, form, and product cohesiveness has always been a major stumbling block in developing products with buckwheat. Thus, for commercial production of buckwheat noodles, gluten or wheat flour is almost always added to the raw ingredients [168,169,170].

Hele, a type of Chinese noodle, is made of 100% pure CBW flour [168,171] but shows a very porous structure in its cross section under a scanning electron microscope [168]. Soba noodle is another noodle that should contain at least 35% buckwheat to be called soba and is valued for high fiber content [171,172]. Higher UBW substitution rates of up to 80% have been tested in soba noodles, but this gluten dilution results in a non-cohesive dough [172]. However, a 20% substitution rate of wheat flour with CBW has shown the most acceptable eating quality for noodles made with buckwheat [167].

Additionally, CBW is used in some rice noodle recipes. In this case, CBW increases the fiber content and balances the essential AA profile of rice noodles [27]. Moreover, substituting 30% of rice with CBW makes a more integrated and robust starch network, reducing the cooking loss and breaking rate of noodles by 8% and 4%, respectively [27]. However, the addition of more than 30% UBW has an adverse impact on the noodle. In this case, adding more fiber may compete with starch for water absorption and higher lipid content can form an amylose–lipid complex that limits amylose leaching from granules [28].

Pure CBW noodles are very brittle and make turbid soup [167]. Different approaches have been used to improve these noodles. Creating an alkaline condition in the dough with 0.4% calcium hydroxide can help improve the swelling power of the starch granules [168]. Moreover, the calcium–starch interaction creates a compact and uniform gel network that improves the texture of cooked noodles. Noodles treated with calcium hydroxide form a starch–protein–fiber network, while untreated noodles have a non-uniform microstructure [168].

Pre-gelatinization is another approved method useful for improving noodle quality. Pregelatinized starch in buckwheat noodle dough creates a gluten-like network that traps air bubbles to enhance processing properties and the quality of the finished product [27,169,171]. Extrusion affects the dynamic viscosity of the flour, which impacts noodle quality. A low viscosity increases breakage and cooking loss as starch molecules degrade and dissolve more readily in water [173].

In addition to extruding, other methods, including roasting, microwaving, steaming, and boiling, have been tested for pregelatinizing TBW flour [174]. Though, to different extents, all methods significantly influenced the functional and structural properties of TBW flour and noodle.

Different buckwheat species have different nutritional and physicochemical properties that can impact noodle quality [172]. Therefore, more investigation is needed to understand the behavior of different buckwheat, especially CBW, under different treatments to process noodles.

3.3.6. Beer and Malting

Beer is a classic low-alcohol drink widely consumed worldwide [30]. The annual per capita beer consumption is predicted to be 5.11 million hL day⁻¹, increasing yearly [175]. The United States (46%) and Europe (43%) are the biggest craft beer producers around the world [175]. Beer is nutritionally rich in AA, carbohydrates, vitamins, minerals, and phenolic compounds that differ from beer to beer based on the raw ingredients used and the many processes performed during brewing (milling, mashing, and fermentation) [30]. Malted barley and malted wheat, two gluten-containing grains, are the key ingredients for beer production. It is feasible to produce CBW malt of a high quality suitable for making GF beer and functional beverages by malting 100% CBW under optimal conditions [176].

Of all pseudocereals, buckwheat is the only one that contains rutin, a flavonoid with antioxidant, anti-inflammatory, and anticarcinogenic properties [30,31]. However, the process influences the amount of rutin in the TBW beer. According to research by Deng et al. [31], who used TBW malt as a brewing adjunct to produce rutin-rich lager beer, differences in mashing methods affected the rutin levels in beer. Beers containing TBW malt and brewed with an improved mashing process had about 60 times more rutin than those brewed traditionally. The rutin content correlated with the antioxidant activity of TBW beer. Rutin-enriched lager beers showed a strong antioxidant capacity and oxidative stability during forced aging. Additionally, the flavor and taste of buckwheat beers were found to be satisfactory.

Buckwheat has sufficient qualities to substitute barley in the commercial manufacture of GF beer, resulting in lower fermentation and the ability to reuse the yeast used in the fermentation process at least 11 times [177]. This pseudocereal has a lower extract yield than barley malt, but similar fermentable carbohydrate, total protein, and free amino nitrogen concentrations [178]. Meo et al. [176] studied the alkaline steeping effect on the pseudocereal, including CBW, for GF beer production. The study result shows that the total soluble N and free amino N content of CBW increased by around 500 and 1000 mg L⁻¹, respectively, by alkaline steeping. Additionally, malting also helped to prevent microbiological contamination.

Overall, buckwheat has antioxidant, anti-inflammatory, and anticarcinogenic qualities, making it an ideal pseudocereal for malting and beer manufacturing. Making pure buckwheat beer and malt with increased health benefits may be possible if the effects of the processing procedures on these attributes are considered.

4. Conclusions

In this review, we identified several opportunities to enhance the performance of CBW in WWA cropping systems and food products that could be disseminated into regional food systems.

While CBW could be a valuable option for a short-season weed-suppressive cash crop in WWA, there are opportunities to strengthen CBW production systems in WWA by selecting regionally adapted varieties for the region. The production of buckwheat in this region should focus on the selection and development of varieties and management strategies that improve crop establishment, early biomass accumulation, and tolerance to early season flooding. Another factor that could impact the success of CBW in WWA is heat stress at flowering. In some regions, planting time could be modified so that flowering time does not coincide with peak summer temperatures. Alternatively, heat tolerance and early maturity would be important to prioritize in buckwheat breeding in the region. These traits would be novel to emphasize in a North American buckwheat breeding program as programs have historically emphasized test weight, self-compatibility, and quality for export markets.

As we looked at the potential for CBW in WWA food systems, we found limited information about the proximate and functional properties of CBW and TBW in the literature. This is a critical knowledge gap because the physicochemical properties of ingredients affect their behavior in food formulations and, thereby, food quality. As buckwheat is high in fiber and GF, it could be used in value-added products. However, the lack of gluten structure could negatively influence product quality in certain food formulations, such as bread. A partial substitution with wheat flour or various additives has been successfully incorporated into the formulation to solve this issue. Nonetheless, further research could be conducted on the influence of various processing methods on BF or buckwheat fractions to enhance its functional properties and improve buckwheat as a functional ingredient.

Moreover, we found extremely limited information regarding the physiochemical properties of specific buckwheat varieties and their correlation to final food product quality. This knowledge could impact target varieties for large-scale food producers and optimize formulations for particular varieties that become popular for production in the region. Similarly, this information could guide variety selection for buckwheat producers or market selection for the varieties that grow best in their operations. Addressing this gap could help researchers in both the crop and food science spaces align their efforts to integrate buckwheat into the regional food system. Understanding the impact of variety and location on CBW performance for different food products will be critical to match production to regional market opportunities.

Additionally, factors such as scale and infrastructure requirements must be identified to successfully link producers with end-use processors. For example, opportunities may vary for small-scale processors, such as individual restaurants, compared to mid-scale processors, such as regional bakeries, and large-scale processors, such as grain distributors that reach national markets. Small-scale producers may be able to leverage their market potential through cooperative approaches to marketing. Large scale food processors would require flour in bulk that has a consistent quality. This would ease the integration of buckwheat into their formulations and production lines.

Infrastructure gaps can potentially restrict any of these opportunities, particularly when attempting to contain all steps in the supply chain to WWA or the Pacific Northwest. Buckwheat is a GF grain, which is a marketable feature, but there are no GF seed cleaning facilities in the region. Therefore, if a regional processor were certified GF, they would have to look outside of the region to source clean seed or ship seed produced in WWA outside of the region to be cleaned, breaking the regional supply chain. Dehulling is another important processing step for many end users that require scale-dependent specialty equipment. Dehulling facilities may be limited. When dehulling is not required, stone mills, which are more readily accessible in WWA, can be used to produce CBW flour. Malting is another potential market for CBW; while it does not require dehulling or milling, it may require GF cleaning, depending on the processor.

A number of funding and partnership opportunities are available and should be leveraged to overcome these infrastructure challenges. In 2023, the USDA launched 12 Regional Food Business Centers to support farmers in accessing new regional markets through coordination, technical assistance, and funding for projects that will help fill gaps in regional supply chain infrastructure (ams.usda.gov/services/local-regional/rfbcp). Additional USDA grant programs that may be relevant to stakeholders in our region include Rural Business Development Grants, Community Facilities Grant, and Value-Added Producer Grants. Ports and regional business development centers can also support the cooperative purchasing of key infrastructure (e.g., storage, grain dryers). Some organizations such as The Rodale Institute (rodaleinstitute.org/consulting) and Mad Agriculture (madagriculture.org/mad-markets) offer regional market consulting to identify gaps in the supply chain, coordinate infrastructure efforts between parties, and help create viable markets for unique products and management practices. Further development and expansion of programming that bolsters and creates resiliency in the middle of the supply chain is needed to support producers and processors who want to adopt novel crops such as CBW.

Building a functional regional supply chain for CBW will take time and cooperation from stakeholders in production and processing. Producers will need the security of a reliable market in order to incorporate the crop into their rotations, but the infrastructure to support that market will not be developed until there is a sufficient need within the region. This need is fueled by end-use processors seeking regionally produced CBW. The physiochemical characteristics, functional properties, fractions, and product development considerations described above will inform these end-use processors of potential opportunities for CBW to be utilized and start building momentum toward a functional regional supply chain.