Summary In the present study, rice bran protein (RBP) from the PB1121 variety was hydrolysed using trypsin and subjected to non‐targeted IMS profiling to identify antioxidant and antihypertensive amino acids in the resulting RBP hydrolysates. The hydrolysate was then separated into three fractions using ultrafiltration, and each fraction was tested for antioxidant and ACE inhibitory activities. The ACE activity was assessed using the tripeptide hippuryl‐histidyl‐leucine (HHL) as a model peptide via HPLC‐DAD. The fraction with the molecular weight (>3000 Da) displayed the strongest antioxidant and ACE inhibitory activity. This fraction was further divided into five fractions using gel Sephadex G‐25, and the greatest levels of antioxidant and ACE inhibitory activity were found in fraction F3B. Fraction F3B was then fractionated using HPLC, and the fraction with ACE inhibitory activity (IC 50 of 43 mg mL −1 ) was analysed using MALDI‐TOF‐TOF mass spectrometry to determine its exact molecular mass and amino acid sequence. The amino acid sequence FMKSK (phe‐met‐lys‐ser‐lys) with a Mw of 655.376 Da was detected, and the molecular docking investigation revealed that FMKSK suppresses ACE by forming strong hydrogen bonds with the active pockets of human ACE. These findings suggest that rice bran contains bioactive peptides with antioxidant and ACE inhibitory effects, making it a promising raw material for the production of beneficial products.

Summary Rice bran protein isolates and seven legume protein isolates (moong bean, green pea, white pea, black chickpea and white chickpea, soya bean and lentil) were evaluated for functional, structural and metabolomic properties. Rice bran protein isolates (RBI) had higher solubility, foaming, oil absorption capacity and water absorption capacity but lower denaturing temperature compared to legume proteins. The functionality of proteins isolates impacted significantly with structural characteristics. The β ‐sheet, α ‐helix, β ‐turn and anti‐parallel β ‐sheets proportions were evaluated by FTIR. RBI revealed lower molecular weight, less rigid conformational structure and lower proportion of β ‐sheet. The evaluation of untargeted metabolomics compounds was determined by ultraperformance liquid chromatography quadruple time‐of‐flight ion mobility mass spectrometry (UHPLC‐QTOF‐IMS), evaluated using PCA and presented as a heatmap. Analysis revealed 46 metabolites including sugars, amino acids, lipids, terpenoid, phenolics, saponins and their derivatives. Significant differences in selected compounds from 126 identified metabolites among protein isolates were observed. This work provides new insights into metabolite distribution among protein isolates and also presents future implementations for applications in food and nutraceuticals.

This study aimed to substitute egg albumin with eight plant-based protein isolates and xanthan gum for the development of gluten-free, eggless muffins. The presence of protein isolates led to reduced pasting viscosities, suggesting limited swelling capacity of the starch granules. Incorporating different protein isolates enhanced the batter's viscoelastic properties, marked by an increase in storage and loss modulus and a decrease in tan delta, indicating enhanced gel properties compared to starch-only batters, which showed more liquid-like characteristics. Consequently, the muffins exhibited greater specific volume, springiness, and cohesiveness. The consistency of the muffins varied depending on the protein isolates used. The inclusion of protein isolates also altered the crust's hue, shifting it towards a reddish-brown shade, while the crumb colour varied with protein incorporated. Sensory evaluation demonstrated that overall acceptability of the muffins improved with the protein isolates, particularly for those incorporating mung bean protein isolate. Principal Component Analysis further highlighted the strong associations between specific quality attributes, underscoring the significant impact of protein isolates on the quality characteristics of gluten-free muffins. Comparing the effect of blending of protein isolates from plant source with wheat corn and rice starches to evaluate the viscoelastic, rheological, textural characteristics of gluten free eggless muffins. image

Background and ObjectivesThe aims of this study were to assess the functional and phytochemical characteristics, as well as the antioxidant properties, of bran from five distinct rice varieties. Additionally, it evaluated the impact of extrusion cooking on the composition and quantity of individual phytochemicals in both free and bound states in the bran of these varieties.FindingsThe functional properties and phytochemical profiles of raw and extruded rice bran from different rice varieties differed significantly. The extrusion process significantly influenced the color, protein solubility, foaming properties, polyphenolics, and amino acid composition of rice bran. Total phenolics ranged from 3.18 to 4.80 mg GAE/g, increased by 12.6%-17% postextrusion. Similarly, total flavonoid content ranged from 15.22 to 17.37 mg RTE/100 g, with a 30%-33% increase after extrusion cooking. Throughout the extrusion process, a rise in the concentration of free phenolics accompanied by a decrease in the concentration of bound phenolics was observed.ConclusionThe study revealed the impact of extrusion cooking on the distribution of total phytochemicals, particularly phenolics and flavonoids, and the levels of antioxidant activity in free and bound phenolics, as well as amino acid composition and functional properties. The extrusion cooking increased levels of free phenolics and 2,2-diphenyl-1-picrylhydrazyl activity, while bound forms decreased. Extrusion cooking variably impacted the functionality and phytochemical content of bran from different rice varieties, thus influencing their likely applications.Significance and NoveltyThis study established the foundation for producing food products using extruded rice bran, offering health benefits and meeting the growing demand in the functional food sector.

Background and ObjectivesTo optimize the utilization of rice by-products, the rice bran protein hydrolysate (RBPH) was subjected to a process of separation and purification using ultrafiltration and reversed-phase high-performance liquid chromatography (RP-HPLC). Subsequently, the identification of peptide sequences was carried out using mass spectrometer hybrid quadrupole-time-of-flight and nontargeted metabolomic profiling done using UHPLC-QTOF-IMS profiling to identify antioxidant and antihypertensive amino acids.FindingsThree novel bioactive peptides, namely, STCCK, FMKSK, and KICILVFTLTTC, were identified within RBPH through enzymatic digestion using alcalase, pepsin, and trypsin. These peptides showed significant antioxidant activity and angiotensin-converting enzyme (ACE) inhibitory activity. Molecular docking analyses elucidated various interaction mechanisms between these peptides and the ACE receptor protein, including hydrogen bonding and hydrophobic interactions. This suggested that the peptides effectively suppress ACE by forming hydrogen bonds with the active pockets of human ACE with a high affinity.ConclusionIn summary, peptides derived from rice bran protein exhibited distinguished antihypertensive and antioxidant properties, underscoring their potential for valuable utilization in addressing utilization of rice by-products.Significance and NoveltyThe study advances scientific knowledge and offers practical solutions for health improvement and sustainable agriculture.