Advances in Chemistry, Quality, and the Processing of Grain and Oilseed Crops

1. Introduction

The last ten years have seen tremendous pressure placed upon the world’s food systems due to rising demands caused by increasing population numbers, increased urbanization, climate-related pressures, and the growing burden of chronic diseases associated with dietary choices. These pressures have revived interest among scientists and industry leaders with regard to plant-based staples. Cereal, pseudocereal-, legume- and oilseed-based staple foods continue to be the cornerstone of human and animal nutrition globally; however, they are being reimagined from simple caloric providers to multifunctional vehicles of protein, minerals, and bioactive compounds in healthy and sustainable foods [1,2,3].

Alongside the recent resurgence in interest in these staple foods, there has been a rapid evolution toward plant-based dietary patterns, which has driven the expansion of markets related to plant-based beverages, meat/dairy substitutes, and functional snacks. Legume-, cereal-, pseudocereal-, and oilseed-based proteins have become increasingly recognized as lower-impact alternatives to animal-based proteins, providing that technical functionalities (digestibility, amino acid balance, and allergen potential) are effectively managed [4,5]. For example, plant-based milks and cereal–legume-based beverages are engineered using high-pressure homogenization, ultrasonication, pulsed electric fields, and fermentation to enhance their stability, sensory characteristics, and the bioavailability of their nutrients [6,7].

Simultaneously, climate-resilient “neglected” grains such as millets, sorghum, finger millet, teff, and pigmented rice are gaining prominence as “smart” crops for food and nutrition security in areas with limited access to water and areas experiencing extreme temperatures [1,8,9,10]. Drought-tolerant millets and sorghum possess high levels of nutrient density; however, they suffer from limitations related to their short flour shelf lives, processing requirements, and value chains that need to be strengthened with applicable technologies and market development [1,8]. Like the case of millets and sorghum, pigmented cereals and pseudocereals—such as black rice, colored wheat, quinoa, amaranth, and buckwheat—are being selectively promoted due to their high levels of anthocyanins, phenolics, and other phytochemicals possessing antioxidant, anti-inflammatory, and metabolic health benefits. Pigmented cereals and pseudocereals are increasingly utilized in premium bakery, beverage, and snack products [9,10,11].

Beyond traditional proximate analysis, a more complex understanding of grain chemistry is needed to comprehend and make use of this variability. The focus has moved toward understanding the chemical and physical properties of grain components. Storage protein structure and digestibility, starch architecture and resistant fractions, lipid and phytosterol compositions, mineral species, and numerous low-molecular-weight phytochemicals and volatile organic compounds (VOCs) are all important features of grain chemistry [4,5,12]. VOCs in cereals are being recognized as key contributors to flavor/aroma and as sensitive indicators of biotic/abiotic stresses, spoilage, and processing history, with the major classes consisting of alcohols, aldehydes, alkanes, esters, fatty acids, and phenols [3].

In addition, the use of biofortification and breeding to improve the nutritional content of staple foods is becoming a common practice to address micronutrient deficiencies without compromising the agronomical performance of the crop. Advances in enhancing the concentrations of iron, zinc, folate, and vitamin E in staple foods such as rice, wheat, corn, pulses, chickpeas, lentils, and sesame illustrate how genetic engineering and gene editing can significantly alter the nutritional profile of staple foods [2,13]. However, addressing the integration of nutrient density with a stable yield, quality traits, and farmer acceptance continues to present a significant challenge [13].

Furthermore, the assessment of staple foods’ quality is developing quickly. Conventional chemical and chromatographic methods are still accurate and commonly employed to evaluate the quality of staple foods; however, they are being progressively supplemented or replaced with rapid, non-destructive analytical techniques. Near-infrared (NIR) and mid-infrared (MIR) spectroscopy, hyperspectral imaging, and synchrotron-based infrared microspectroscopy allow for the in situ investigation of the composition and microstructure of individual kernels or flour particles, thus providing insight into the spatial distribution of proteins, starch, and cell wall components and how they change in response to stresses or processing [14]. Chemometric models and deep learning algorithms (CNNs, GANs, etc.) are being increasingly used to identify varieties, detect adulteration, predict the concentrations of various compounds (protein, starch, oil, micronutrients, and non-starch polysaccharides), and determine the geographic origin of samples with high precision [14].

GC-MS, LC-MS/MS, and metabolomic analysis continue to play critical roles in defining the identity of volatile, mycotoxin, and fermentation metabolite compounds in foods and feeds, thereby providing additional links between processing conditions and their impacts on food/feed safety and functional/sensory properties [15,16]. Modern analytical techniques are similarly being employed to define the relationships between microbial communities and their functions in cereal-based fermented foods, as well as the linkages between bioactive compound production (GABA, etc.), gut health, antioxidant activity, and organ protection [17].

In terms of processing, both incremental and disruptive technologies are transforming how cereals, pseudocereals, legumes, and oilseeds are processed. Traditional unit operations (milling, soaking, germination, malting, cooking, extrusion, and fermentation) are being optimized to increase digestibility, decrease antinutritional factors, and tailor functional properties (water and oil binding, emulsifying, gel forming, foam forming, etc.) [6,9]. At the same time, innovative thermal and nonthermal approaches (ohmic heating, microwaving, radio frequency heating, infrared heating, high-pressure processing, pulsed electric field treatment, cold plasma treatment, ozone treatment, sonication, and hybrid drying schemes) are being used to stabilize flours, extend shelf life, modify starch and protein structures, and preserve labile nutrients and phytochemicals [1,12].

Another rapidly developing area of research is related to the encapsulation and nanostructuring of plant-derived bioactives. Proteins, starches, and fibers from legumes, cereals, and by-products are being engineered, often in conjunction with polysaccharides, into micro/nano-carriers capable of protecting sensitive compounds (polyphenols, carotenoids, vitamins, unsaturated lipids, and probiotics) during processing, storage, and gastrointestinal passage, and also facilitating the controlled release and enhanced bioavailability of these compounds [18,19]. This area of research is also consistent with the utilization of agro-industrial waste streams and residues rich in phenolic and other bioactives, and therefore represents an opportunity to integrate grain processing with the principles of circular bioeconomy and sustainability [13,18].

In addition, the formulations of plant-based foods are increasingly being developed as multi-source by design, utilizing combinations of cereals, pseudocereals, legumes, and oilseeds to achieve complementary amino acid profiles, improved textures, and enhanced levels of micronutrients, while decreasing dependencies on refined wheat flour and animal products [4,5,20]. In baked goods, snacks, pasta, beverages, and meat analogs, the strategic deployment of ingredients (aquafaba, legume flours and isolates, plant-based emulsifiers, and exopolysaccharides) are serving as structure-forming and clean-label functional additives [6,18,21].

2. An Overview of Published Articles

This Special Issue, ‘Chemistry, Quality, and Processing Technology of Different Cereals, Pseudocereals, Legumes and Oilseeds Grain Types’ brings together five research articles highlighting recent advancements related to the quality of the raw materials used, and their impact on technological processes and food products’ quality. These researchers explore the chemical composition, nutritional characteristics, and processing technologies associated with a variety of grain types such as cereals and oilseeds.

The paper ‘Corn-Based Extruded Snacks Supplemented with Bilberry Pomace Powder: Physical, Chemical, Functional, and Sensory Properties’ by Ana Maria Blejan et al. (Contribution 1) developed new corn-based extruded snacks with bilberry pomace powder (BPP) in their recipe. According to the results, the most successful corn-based extruded snack was the one with 6% BPP addition, which presented the most improved nutritional value and the best sensory characteristics.

The paper ‘Evaluation of Selected Properties of Corn Snacks Enriched with Pomace from Common Flaxseed (Linum usitatissimum L.) and Golden Flaxseed (Linum flavum L.) with the Addition of Cocoa’ by Ewa Tomaszewska-Ciosk et al. (Contribution 2) developed corn snacks with added cocoa and enriched with pomace from various flax varieties. The developed products received high sensory appreciation from the panelists with the highest contribution from the cocoa addition on the color value. The best extruded snacks’ formulation should have up to 10% common falx pomace and cocoa incorporation in the recipe.

The article ‘Pre-Treatment of Vegetable Raw Materials (Sorghum Oryzoidum) for Use in Meat Analog Manufacture’ by Viorica Bulgaru et al. (Contribution 3) analyzed the soryz grain’s (a good source of amino acids and minerals K, Mg, and Ca) hydration kinetics, in terms of its dependence on temperature and time. According to the data obtained, the soaking conditions can be optimized, which allows us to obtain raw material that may be used in meat analog manufacturing.

The article ‘Can Kernel Uniformity Indices Be Used as Criteria for Variability Assessment of Wheat Breeding Lines?’ by Ioanna M. Protasova et al. (Contribution 4) presented new knowledge about the relationship between different kernel parameters such as the length, cut, area, width, depth, and perimeter on the morphology and quality of bread wheat, which may be the subject of further research related to the improvement of grain weight performance.

The article entitled ‘Study on Optimization of Rice-Drying Process Parameters and Directional Regulation of Nutrient Quality’ by Jinquan Li et al. (Contribution 5), using Design Expert software, analyzed the relationships between the drying parameters of rice, namely the hot air temperature, initial moisture content, humidity, resting time ratio, and wind speed, and its nutrient compounds, fat, protein and starch content. According to the results, the optimal drying process parameters obtained were 30.120% for humidity, 48.871 °C for hot air temperature, 21.312% for moisture content, 0.621 m/s for wind speed and 2.867 for the resting time ratio.

3. Conclusions

The research presented in this Special Issue highlights the possibility of obtaining new corn snacks enriched with different functional ingredients such as bilberry pomace powder or different flaxseed types and cocoa. These new corn snacks obtained and analyzed were of higher quality from a nutritional and sensory point of view. Different kernel parameters were shown to impact grains’ quality, and different pre-treatments of soryz grains allowed us to obtain raw material that may be used in meat analog manufacturing. Also, using Design Expert software (V8.0.6.1), the optimal drying process parameters for rice were obtained. These studies reflect the new trends in developing new food products based on grain and oilseed crops like flaxseed, the optimized technologies for grain processing, such as the for processing of rice and sorghum, and the new possibilities for predicting grain quality based on kernel parameters’ values.