ABSTRACT Background and Objectives Enzymatic hydrolysis has been established as an effective strategy to improve the functional properties of plant proteins. Rice proteins are particularly attractive because of their hypoallergenic nature, high nutritional value, and sustainability, although their technological applications remain limited by their low water solubility. This review evaluated the effects of the degree of hydrolysis (DH) on the technological properties of rice proteins, focusing on functional attributes relevant to food applications. Findings A total of 33 studies published between 2012 and 2025 were critically reviewed to evaluate the relationship between the degree of hydrolysis and the technological properties of rice proteins. Overall, low to moderate degrees of hydrolysis (5%–10%) produced hydrolysates with improved solubility over a wide pH range, enhanced emulsifying properties, greater foam stability, and increased water and oil holding capacities. In contrast, higher DH values (> 12%–15%) generally resulted in a greater proportion of short peptides, which were associated with reduced colloidal stability, lower foaming capacity, and more pronounced undesirable flavors. Gel‐forming ability was more effective at low hydrolysis levels (< 5%). Conclusions The findings demonstrate that careful control of the degree of hydrolysis is essential to maximize the technological functionality of rice proteins while minimizing adverse sensory effects. Optimized enzymatic hydrolysis enhances the potential of rice protein hydrolysates as sustainable and versatile ingredients for the development of innovative food products.
ABSTRACT Background and Objectives Whole‐grain (brown) rice has superior nutritional quality but is prone to rancidity, primarily caused by endogenous lipases and oxidases. This study evaluated mild hydrothermal stabilization (MHS), comprising grain surface wetting, followed by short‐duration atmospheric‐pressure steaming, applied to two West African rice varieties. Rice was processed as mild hydrothermal stabilized paddy whole‐grain rice (MHS‐PWGR) and brown whole‐grain rice (MHS‐BWGR). Findings With both MHS‐PWGR and MHS‐BWGR, lipase activity was not detected after 10 min steaming. Peroxidase activity was not detected after 5 min steaming. MHS improved grain lightness compared with conventional parboiling, giving a golden‐yellow color. MHS‐BWGR maintained acceptable brown head rice yield and essential mineral content (Fe, Zn, and Ca), (quantified by XRF). Cooking time and cooked‐grain hardness were reduced, particularly in MHS‐BWGR. Conclusions Multi‐criteria decision analysis of the data identified 15 min steaming of MHS‐BWGR as the optimal treatment, combining undetectable enzymatic activity, good color, texture, and mineral quality. Significance and Novelty MHS has considerable potential as a simple and effective process for improving the shelf life and quality of whole‐grain rice. It can be readily deployed with slight modifications to existing parboiling systems already in West African small‐ and medium‐scale rice mills and elsewhere.
ABSTRACT Background and Objectives Copra meal is a byproduct of the coconut oil extraction process and provides an inexpensive source of energy for livestock diets. Single‐screw extrusion was conducted to investigate the effects of varying proportions of copra meal and distillers dried grains with solubles (DDGS) and the corresponding processing parameters on the physical properties of the resulting extrudates. Findings Five distinct feed blend compositions (0%, 25%, 50%, 75%, and 100% DDGS) were tested alongside three levels of moisture content (35%, 45%, and 55% wet basis) and three screw speeds (270, 590, and 880 rpm) as independent variables and their effects on extrudate physical properties (water activity, bulk density, unit density, expansion ratio, color, pellet durability index, water absorption index [WAI], water solubility index [WSI]). Conclusions Despite the low starch content of both copra meal and DDGS, viable extrudates with comparable physical properties, including extrudate durability, hydration parameters, and expansion, were produced. The results indicated that the composition of the feed blend was the primary factor significantly influencing all the physical properties of the extrudates. Feed blends containing higher proportions of DDGS resulted in improved extrudate durability and bulk density. However, substituting DDGS with copra meal led to a decrease in unit density and WSI and higher WAI, suggesting better floatability and water stability properties. Significant changes in color parameters (L*, a*, and b*) were also observed among the treatments, primarily influenced by moisture content rather than feed composition or screw speed. Significance and Novelty These findings highlight the crucial role of formulation and processing conditions on the characteristics of the resulting extrudates. Both DDGS and copra meal can be successfully used as feed ingredients in extrusion processing to produce viable extrudates. The results of this study can serve as a starting point to determine optimal inclusion rates of both products in feed production and processing parameters during extrusion to achieve the desired physical characteristics based on the feeding behavior and nutritional requirements of intended species.
ABSTRACT Background and Objectives Parboiling improves rice milling performance but often imparts undesirable color changes affecting consumer acceptance and market grading. This study evaluated quantitative approaches for objectively classifying parboiled rice color and predicting degree of milling across eight modern rice cultivars as instrument‐based alternatives to the qualitative USDA visual grading system. Cultivars were parboiled and milled at five durations (20–80 s), and surface lipid content (SLC), total lipid content (TLC), CIE L *, and whiteness index (WI) were measured and evaluated against USDA parboiled rice color standards. Findings Increasing milling duration consistently reduced SLC and TLC while improving L * and WI across all cultivars. While most cultivars achieved the Parboiled Light (PBL) color grade at 20 s, a milling duration of 40 s was sufficient to achieve the PBL color grade for all eight cultivars. Aroma 22 showed the greatest resistance to pigment removal, transitioning to the PBL color grade at an SLC of 0.39%, WI of 20.55, and L * of 56.84 at 40 s of milling. A novel calibration model (TLC = 1.10 × SLC − 0.03; Adjusted R 2 = 0.830, RMSE = 0.088) was developed specifically for parboiled rice, enabling rapid NIR‐based estimation of TLC from routine SLC measurements. Conclusions These findings provide preliminary quantitative benchmarks linking instrumental color measurements to USDA parboiled rice color grades for modern rice cultivars. Significance and Novelty The study provides a potential instrument‐based approach that could complement visual grading standards, currently employed in commercial rice processing operations.
Background Pearl millet (Pennisetum glaucum) is widely promoted as a mineral-rich substitute for refined wheat in baked products, yet this nutritional claim is rarely tested against two countervailing effects: loss of fortification-derived minerals as the regulated wheat premix is displaced, and progressive accumulation of phytic acid, a potent chelator that reduces iron bioaccessibility.Methods Composite cakes were prepared with pearl millet flour at 0%-50% substitution and characterized for functional, proximate, mineral, antinutritional, and sensory properties.Results Intrinsic minerals rose, with iron increasing from 54.8 to 90.8 mg/kg DM, but total ash fell from 2.43% to 1.12% as the fortified premix was displaced, and phytic acid rose faster than iron, driving the phytate:iron molar ratio from 1.31 to 1.58, above the 1.0 inhibitory threshold at every level, including the control. The apparent iron gain is therefore not bioaccessible without phytate reduction. Phytate:calcium ratios stayed below threshold, and sensory acceptability held through 30% substitution.Conclusion The 20% formulation is recommended as the practical optimum.
