Search Results (53)

Parboiled rice hull mulch is becoming a widely used non-chemical weed control method in container nurseries, but research is lacking on the performance of rice hulls in outdoor production nursery environments. Two separate experiments were conducted to assess the effect of rice hull mulch on the emergence and growth of several common nursery weed species in an outdoor container nursery environment and to determine how well rice hulls performed over time. In a 12-week container experiment, rice hulls provided significantly better control of common container nursery weed species when seeds were placed on top of rice hull mulch applied at depths of 1.3 or 2.5 cm. In contrast, there was little difference in control when seeds were placed below the mulch layer regardless of mulch depth. In a long-term evaluation over 12 months, rice hulls applied at depths of 1.3, 2.5 or 5.0 cm provided control similar to pre-emergence herbicides through 6 months, but herbicides provided better control thereafter. Overall, rice hulls proved to be a suitable alternative to commercial herbicides and would be recommended in cases where pre-emergence herbicides cannot be used due to crop safety or grower preferences. Full article

Parboiling enhances the nutritional, structural, and economic value of rice, yet its adoption in the United States remains limited despite rising domestic and export demand. This review summarizes key stages of the parboiling process and their effects on milling yield, grain integrity, nutrient retention, and glycemic response. It outlines major industry challenges, including high energy and water use, uneven heating and drying, handling of defective kernels, limited automation in smaller mills, labor shortages, and emerging climate-related risks. Advances such as vacuum soaking, infrared and microwave-assisted drying, smart sensors, and AI-driven control systems show strong potential to improve efficiency and product quality. Circular-economy strategies, including biomass energy recovery, water reuse, and by-product valorization, offer additional sustainability gains. Continued research, modernization, and policy support are critical to strengthen competitiveness and positioning of the U.S. parboiled rice sector for a more resilient and sustainable future. Full article

Parboiling improves rice-milling performance and consumer acceptance; however, drying parboiled rice can be energy intensive and highly sensitive to drying conditions, making it costly for processors. High head rice yield (HRY) and whiteness index (WI) are essential for commercial value because they reduce breakage and improve visual quality. In the United States, parboiled rice is typically dried in a two-stage process using rotary drum and crossflow dryers, but the high temperature condition of rotary drums can increase energy demand and compromise rice quality. This study evaluated the drying kinetics, effective moisture diffusivity (D_eff), energy consumption, and quality for three common cultivars (CLL 18, RT 7521, and Titan) using four methods: natural air drying (NAD), two-pass hot air oven drying (OO), two-pass fluidized bed drying (FBD), and a hybrid of oven and fluidized bed method (OFBD). Moisture content (MC) was monitored during drying until 12.5% (w.b.) to understand the drying kinetics. FBD achieved the fastest drying, reducing Titan MC from 38.24% to 13.79% (w.b.) in 60 min (two passes). It also produced highest D_eff across cultivars and consumed less energy (1.6599 kWh) as compared to OFBD (1.6733 kWh) and OO (1.68 kWh). Among nine thin-layer models explored, the logarithmic model provided the best fit, and Midilli–Küçük and Verma et al. models performed better in specific cases. NAD produced a higher quality of HRY (Titan: 65.33 ± 2.07%) and WI (RT 7521: 63.99 ± 0.25) than FBD but required 7–10 days to reach the target moisture content, limiting industrial applicability. Results from this study show that drying method and rice cultivars significantly influenced parboiled rice quality, and FBD offered efficient drying without compromising parboiled rice quality. Full article

This study aimed to extract rice bran oil rich in γ-oryzanol from white (WB) and parboiled rice bran (PB) using ultrasound as a pre-treatment to supercritical fluid extraction (US + SFE), supercritical fluid extraction (SFE), and conventional solvent extraction. PB oil exhibited superior quality compared to WB, with low free fatty acid (FFA) levels and higher γ-oryzanol content. PB oil extracted by US + SFE achieved a yield of 18.2 ± 0.4%, γ-oryzanol content of 1.53 ± 0.19 g 100 g⁻¹, and low FFA content (0.27 ± 0.01%), showing improved oil quality compared to SFE (yield 13.5 ± 0.3%, γ-oryzanol 1.13 ± 0.08%, FFA 0.55 ± 0.01%) and conventional extraction (yield 25.0 ± 1.3%, γ-oryzanol 2.03 ± 0.04%, FFA 1.12 ± 0.01%). The US + SFE oil also showed lower peroxide value (1.7 mEq kg⁻¹) and preserved fatty acid profiles containing palmitic, oleic, and linoleic acids. US induced structural disruption in bran, enhancing oil release. Additionally, chitosan–gelatin nanoemulsions were developed to protect the extracted oil. Formulations exhibited droplet sizes of 119–352 nm, polydispersity indices below 0.3, and zeta potentials from –12.4 to 38.8 mV. Gelatin-based nanoemulsions maintained FFAs at 0.56 ± 0.2% and peroxide values at 4.71 ± 0.2 mEq kg⁻¹ over 90 days, demonstrating superior oxidative stability. These results highlight the potential of US and SFE combined with nanostructured delivery systems to valorize agro-industrial byproducts and develop stable, functional ingredients and drug carrier systems. Full article

Extruded whole flours from blends of cereals and pulses have great potential to be key ingredients in the development of more innovative gluten-free products, both from a technological and nutritional perspective. The objective of this work was to obtain pre-cooked flours from four formulations based on blends of whole cereals (PR: parboiled brown rice; PM: pearl millet) and pulses (CP: chickpea; CB: common bean). CB was fixed at 10%, and the other components (PR-PM-CP) were set at 60-15-15 (F1), 15-60-15 (F2), 15-15-60 (F3), and 30-30-30 (F4), which were extruded at two combined conditions of feed moisture and screw speed: mild E1 (30% and 300 rpm) and severe E2 (18% and 600 rpm). The temperature profile was kept constant from 25 to 130 °C (from feed to output). The protein, dietary fiber, and ash contents in the raw formulations varied from 11.2 to 17.4%, 9.8 to 15.0%, and 2.2 to 3.3%, respectively, according to the low or high pulse content in the blend. As more mechanical energy was delivered to the raw formulations (W·h/kg, 63.7 for E1 and 179.4 for E2), the extruded particles had increased water absorption (g/g) from 1.7 to 4.5 (E1) or 3.8 (E2), increased water solubility due to E2 from 10.9 to 20.9%, and decreased oil absorption (g/g) from 1.5 to 0.9 (E1 and E2). The peak viscosity (PV, cP) was noticeable only in the raw formulation F2 (355), which decreased 10.3% due to E1. In the other formulations, PV appeared due to E1 in F1 (528), F3 (420), and F4 (371), while it disappeared due to E2 in all formulations. However, at the E2 condition, they did show cold viscosity in the initial stage (222 to 394 cP). The final viscosity (FV, cP) decreased from 795 to 390 (E1) or 123 (E2). In F2, the contents of phenolic compounds (285 µg GAE/g) and ABTS⁺ (13.2 μmol TE/g) were more than twice that in the other formulations, and their respective degradations were low due to E1 (4.2 and 12%) and high due to E2 (16 and 17%). Extrusion cooking did not cause significant changes in the luminosity (81) and redness (0.9) of particles, while yellowness increased from 15.7 to 18.2 (E1) or 18.7 (E2). Based on these findings, it is concluded that both extrusion conditions improved the technological and functional properties. Regarding the formulations, F2 stood out for being rich in antioxidant capacity, which poorly degraded under the conditions studied. Further work is needed to contribute to understanding the optimization of formulas and processes that would improve the nutritional, sensorial, and functional properties while still preserving the bioactive value of the final products. Full article

The growing demand for sustainable biorefinery approaches calls for efficient, environmentally benign strategies to valorize agricultural residues and ensure their complete utilization. This study explores the combination of deep eutectic solvents (DESs) and microwave heating technology as a greener process for the selective fractionation of agri-food waste residues in a zero-waste perspective. Within this framework, five representative biomasses were thoroughly investigated, namely brewer’s spent grain, raw and parboiled rice husks, rapeseed cakes, and hemp hurds. DES formulation was selected for its ability to solubilize and separate lignocellulosic components, enabling the recovery of a polysaccharide-rich fraction, lignin, and bioactive compounds. DES extraction was performed using both microwave heating and conventional batch heating, enabling a direct comparison of the two methods, the optimization of a more sustainable fractionation process, and the maximization of yields while preserving the functional integrity of the recovered fractions. A comprehensive characterization of the separated fractions was carried out, revealing that the two fractionation methods do not yield significant differences in the composition of the primary components. Moreover, a ¹³C CP-MAS NMR analysis of the recovered lignins demonstrates how this analytical technique is a real fingerprint for the biomass source. The results demonstrate the great potential of microwave DES-mediated fractionation as a mild, tunable, and sustainable alternative to conventional methods, aligning with green chemistry principles and opening new approaches for the full valorization of waste byproducts Full article

Vibrational spectroscopy, including Raman and near-infrared techniques, enables the non-destructive evaluation of starch gelatinization, head rice yield, and aroma-active volatile compounds in parboiled rice subjected to varying soaking and drying conditions. Raman and NIR spectra were collected for rice samples processed under different conditions and integrated with reference analyses to develop and validate partial least squares regression and artificial neural network models. The optimized PLSR model demonstrated strong predictive performance, with R² values of 0.9406 and 0.9365 for SG and HRY, respectively, and residual predictive deviations of 3.98 and 3.75 using Raman effective wavelengths. ANN models reached R² values of 0.97 for both SG and HRY, with RPDs exceeding 4.2 using NIR effective wavelengths. In the aroma compound analysis, p-Cymene exhibited the highest predictive accuracy, with R² values of 0.9916 for calibration, and 0.9814 for cross-validation. Other volatiles, such as 1-Octen-3-ol, nonanal, benzaldehyde, and limonene, demonstrated high predictive reliability (R² ≥ 0.93; RPD > 3.0). Conversely, farnesene, menthol, and menthone showed poor predictability (R² < 0.15; RPD < 0.4). Principal component analysis revealed that the first principal component explained 90% of the total variance in the Raman dataset and 71% in the NIR dataset. Hotelling’s T² analysis identifies influential outliers and enhances model robustness. Optimal processing conditions for achieving maximum HRY and SG values were determined at 65 °C soaking for 180 min, followed by drying at 70 °C. This study underscores the potential of integrating vibrational spectroscopy with machine learning techniques and targeted wavelength selection for the high-throughput, accurate, and scalable quality evaluation of parboiled rice. Full article

Rich in bioactive compounds, pigmented rice offers superior antioxidant capacity compared to non-pigmented rice. Processing methods like milling, parboiling, thermal treatments (e.g., extrusion cooking), and biobased approaches (e.g., germination and fermentation) impact the technological and nutritional properties of pigmented rice. All products with added pigmented rice showed improved total phenolic content and antioxidant capacities. Extrusion cooking improved technological properties of dough, bread, and bakery products by modifying the pasting properties of rice. Germination and fermentation enhanced bakery products’ nutritional value by increasing gamma-aminobutyric acid (GABA) levels. Pigmented rice flour can enhance the volume, crumb firmness, and elasticity of gluten-free (GF) bread, especially with ohmic heating. It improved sensory qualities and consumer acceptance of various baked products and extruded snacks. While pigmented rice-based pasta and noodles had compromised cooking qualities, germination improved noodle cooking qualities. Pre-processing techniques like parboiling and micronisation show potential for improving pigmented rice’s technological properties and warrant further study. In conclusion, pigmented rice can enhance the technological and nutritional qualities of bread, bakery products, and snacks. Future researches should focus on agronomic advancement, optimization of pre-processing and processing techniques, exploring varietal differences among pigmented rice cultivars, and promotion of consumer awareness and market potentials. Full article

Type 2 diabetes mellitus (T2DM) represents a significant global health burden, especially in populations where rice constitutes a dietary staple. Parboiled rice (PBR), known for its lower glycemic index compared to conventional white rice (WR), may offer benefits in managing postprandial hyperglycemia. Nevertheless, the impact of PBR consumption on insulin sensitivity, β-cell function, and incretin hormone responses remains poorly understood. Methods: This randomized crossover pilot study aimed to assess and compare the acute effects of PBR and WR intake on postprandial glucose regulation, insulin sensitivity, β-cell functionality, and glucagon-like peptide-1 (GLP-1) responses in healthy subjects and individuals with T2DM. A total of 20 participants were recruited and evenly allocated into healthy (n = 10) and T2DM (n = 10) groups. Following the ingestion of either PBR or WR, blood samples were collected at fasting and various postprandial intervals to determine glucose, insulin, and GLP-1 levels. Insulin sensitivity and β-cell function were evaluated using HOMA-IR, Matsuda Index (MI), and Disposition Index (DI). Results: As expected, T2DM participants exhibited significantly elevated fasting glucose and insulin levels compared to healthy controls. Consumption of PBR led to significantly lower postprandial glucose responses in healthy subjects relative to WR. Although a similar trend of reduced glucose levels was observed in T2DM subjects after PBR intake, this reduction did not reach statistical significance. Parallel trends were observed in insulin secretion patterns. Moreover, GLP-1 responses were notably diminished in T2DM individuals compared to healthy participants. Importantly, MI and DI values significantly increased after PBR consumption in healthy individuals compared to those with T2DM, indicating improved insulin sensitivity and β-cell responsiveness. Conclusions: These preliminary findings suggest that PBR consumption may confer beneficial effects by lowering postprandial glucose and enhancing insulin sensitivity. Further studies with larger cohorts are warranted to confirm these outcomes and elucidate the physiological mechanisms behind PBR’s potential role in dietary management strategies for T2DM. Full article

Rice milling in Sub-Saharan Africa (SSA) remains highly dependent on water availability and favorable weather conditions, making local millers vulnerable to water- and weather-related pressures (WWrP). This study examines how rice millers in Makurdi and Adikpo, Benue State, Nigeria, adapt to these pressures. Data were collected through snowball sampling involving 21 rice millers and two workshops attended by 14 millers. Content and thematic analyses of data were carried out using NVivo 11. Findings indicate that rice milling operations are highly exposed and sensitive to flooding, excessive wetness, dryness, high humidity, and water scarcity. These pressures are likely to intensify due to climate change and pronounced climate variability. To adapt, millers employ endogenous strategies, including temporarily relocating or evacuating mills, rotating drying schedules, modifying drying methods, reducing or suspending parboiling during floods, and digging wells. In spite of these adaptation measures, locally milled rice continues to face issues of poor quality and diminished competitiveness. Consequently, this study highlights upgrading milling technologies and infrastructure, promoting proactive and long-term adaptation measures, and supporting collective adaptation strategies among millers to enhance resilience in the rice value chain. Full article

Rice is a staple food in Côte d’Ivoire, but parboiling remains a weak link in the local rice value chain. Parboiled rice has superior nutritional and physical properties compared with white rice. In 2017, AfricaRice introduced the “Grain quality enhancer, Energy efficient, and durable Material” (GEM) parboiling system in Côte d’Ivoire to address these challenges. This study evaluated the rice value chain, parboilers’ perceptions of GEM technology, and its role in upgrading the rice value chain. Using two survey types (parboiler association level (focus group) and parboiler household level), 179 rice parboilers and 77 key players were randomly sampled and interviewed in Côte d’Ivoire. We used descriptive statistics and the parboiler budget for the profitability analysis. The results show that parboiling, primarily undertaken by women, is profitable in Côte d’Ivoire. Parboilers identified the key advantages of the GEM system, including improved rice quality, higher output rates, better nutritional value, and the ability to parboil larger volumes of rice. GEM technology enhanced rice quality, increased parboilers’ incomes, and reduced energy costs by 22.3%, saving an average of 73,090 FCFA per ton of parboiled paddy. The study recommends scaling up GEM technology through local fabricator training and broader dissemination in rice-growing regions to further strengthen the rice value chain in Côte d’Ivoire. Full article

Xanthan is a highly relevant commercial microbial biopolymer. Its production occurs in two steps: the bacterium is cultivated in a nitrogen-rich medium for cell multiplication, and the obtained biomass is used as an inoculum for the polymer production phase. Different media compositions for cell growth were investigated, seeking to reduce or replace the peptone used in the standard medium. Peptone (P), yeast extract (YE), and rice parboiling water (RPW) concentration combinations were tested in cultivating Xanthomonas arboricola pv. pruni 101. A CRD 2³ design, performed in a shaker, was used to assess the effects of independent variables on xanthan pruni microbial growth, N consumption, yield, viscosity, pseudoplasticity, and xanthan mineral content. After 24 h an increase in N was observed, without any significant impact on cell growth. Xanthan yield increased as a result of the alternative treatments, with P and YE influencing positively. However, T1, with the lowest levels of P, YE, and RPW increased viscosity and pseudoplasticity of xanthan pruni. RPW increased phosphorus, silicon, calcium, and magnesium, and P and YE increased potassium. These results indicate that partial replacement of P by RPW and YE is an economically viable and sustainable approach for the xanthan pruni production. Full article

Endophytic fungi are valuable sources of bioactive secondary metabolites, with potential applications in pharmaceutical and agricultural fields. This study investigates the metabolic potential of Diaporthe hongkongensis, an endophytic fungus isolated from Minquartia guianensis. To date, no secondary metabolites have been identified from this species, highlighting the novelty of this research and its contribution to understanding the chemical diversity of endophytic fungi. The fungus was cultivated on parboiled rice under static and dark conditions for 28 days, leading to the isolation of the following three compounds: 5,6-dihydro-5,6-epoxymultiplolide A (1), cytosporone C (2), and uridine (3). Structural identification was carried out using nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. The results revealed the metabolic versatility of D. hongkongensis, as demonstrated by its ability to produce structurally diverse substances with biological relevance. Hence, it describes the first isolation of secondary metabolites from the endophytic fungus D. hongkongensis, marking a significant step in understanding its chemical profile. The identification of a known antifungal compound and a lactone derivative underscores the biosynthetic potential of this endophytic fungus, while the isolation of a nucleoside expands the chemical repertoire of fungal metabolites, suggesting possible roles in cellular metabolism and stress adaptation. These findings highlight the role of endophytic fungi as prolific sources of structurally diverse and potentially bioactive natural products, supporting further exploration of their biotechnological applications. Full article

Effective blood glucose management is essential for individuals with type 1 diabetes, particularly when dietary adjustments involve staple foods like rice. As a primary carbohydrate worldwide, rice significantly influences the glycemic index (GI) based on its type and cooking method. This study investigated the impact of rice type and boiling duration on the GI in healthy adults using an in vivo approach aligned with ISO 2010 standards. The glycemic response to four rice types (white round-grain, parboiled medium-grain, white long-grain, and whole-grain long-grain) was measured through postprandial blood glucose levels under both standard and extended boiling conditions to assess their implications for dietary glycemic control. Ten healthy participants (mean age 25 years, body mass index (BMI) 23.0 ± 1.6 kg/m²) consumed rice samples containing 50 g of available carbohydrates, prepared under controlled boiling conditions. Postprandial glycemic response was measured at regular intervals over 2 h following ingestion, with glucose solution as a reference food. The GI was calculated based on the incremental area under the glycemic response curve for each rice sample. Extended boiling significantly increased the GI across all rice types. White round-grain rice exhibited the highest relative increase (+15.8%) in the GI, while whole-grain long-grain rice, despite showing a greater percentage increase (+25.4%), maintained the lowest overall GI due to its high amylose and fiber content. Rice types with higher amylopectin content demonstrated faster glycemic responses and higher GI compared to high-amylose types. This study highlights rice type and cooking time as critical factors influencing postprandial glycemic response. Shorter boiling durations may benefit individuals requiring strict glycemic control, particularly those with diabetes, underscoring the importance of personalized dietary guidance for managing glycemic outcomes effectively. Full article

One of the major challenges for crop breeding scientists is climate change. Their task is to develop new crop varieties that can withstand this phenomenon. For this study, a new Egyptian paddy variety called Giza 183, which is designed to adapt to mitigate the effects of climate change, was chosen. We focused on examining the physical and engineering properties of this variety in order to design strategies for storage, handling, transportation, drying, parboiling, and processing equipment in rice mills. The goal was to minimize post-harvest losses during the milling process, thereby maximizing high-quality yields while reducing losses. The physical properties of the rice grains, such as the length, width, and thickness, were measured at an average moisture content of 13.7% ± 0.25% (wet basis). The results reveal that the mean values of length, width, and thickness averaged 7.50 mm, 3.18 mm, and 2.19 mm, respectively. Additionally, the geometric mean diameter, the equivalent mean diameter, surface area, arithmetic mean diameter, and volume were approximately 3.74 mm, 2.38 mm, 37.37 mm², 4.29 mm, and 28.23 mm³, respectively. The mean of sphericity was 49.9%, and the grain shape (length/width) was 2.19. The true density was measured at 1218.28 kgm⁻³, while the bulk density was 572.17 kgm⁻³. The porosity was found to be 53.03%. Furthermore, the milling production rates for brown rice, hull, white rice, and broken rice were determined to be 76.83%, 23.15%, 67.97%, and 17.36%, respectively. The average weight of one thousand grains was 25.49 g. A linear regression model for describing the mass of rough rice grain was investigated. The mass was estimated with the single variable of the grain aspect ratio (width/length) with a determination coefficient of 0.9908. Information gained from the current study will be useful in designing post-harvest processing and storage structures in rice processing industries. Full article