Journal Articles

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Author: search.filters.author.Acevedo-Fani ASubject: search.filters.subject.Hydrolysis

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    Heat-induced modifications of pea protein: Implications for solubility and digestion behaviour
    (Elsevier B.V., 2025-08-20) Li D; Ma Y; Acevedo-Fani A; Lu W; Singh H; Ye A
    Plant proteins have become increasingly desirable due to their sustainability and proposed health benefits. This study initially examined the effects of heat treatment on the solubility of pea protein (PP) in a 3 % (w/w) protein solution, applying heat from 65 °C to 95 °C for varying durations across pH conditions ranging from 5.5 to 7.8. Subsequently, an advanced dynamic gastric digestion model—the Human Gastric Simulator—was employed to examine the in vitro gastric digestion behaviours of heat-treated and untreated PP. Results suggest that heat treatment reduces the protein aggregate size and enhances PP solubility, potentially due to a decrease in α-helix and β-turn structures or an increase in β-sheet content, as determined via Fourier transform infrared spectroscopy. Additionally, heat treatment elevated the surface hydrophobicity and free sulfhydryl group concentration of PP. During in vitro dynamic gastric digestion with pepsin, PP underwent notable structural and physical stability modifications. Unheated and heated PP exhibited small particles in the digesta and remained unaggregated throughout digestion. However, the heat-treated PP showed a smaller particle size during gastric digestion and a greater hydrolysis rate than the unheated protein. This study systematically evaluates the solubility and digestion behaviour of PP subjected to food processing conditions, highlighting its stability and structural changes that may influence the delivery of macronutrients from the stomach to the next phase of digestion.
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    Heat-induced dissociation and association of proteins in hempseed protein bodies
    (Elsevier Ltd, 2025-10) Do DT; Ye A; Singh H; Acevedo-Fani A
    Protein bodies (PBs) are naturally occurring storage organelles in seeds. In hempseeds, the major storage proteins, including edestin (11S globulin) and albumin, are primarily located in the crystalloids and proteinaceous matrices of hemp protein bodies (HPBs), respectively. The retention of native PB structures in flours and dry-fractionated protein ingredients has important implications for protein functionality and digestibility, especially when heat treatment is applied during processing. While the thermal behaviour of hempseed proteins has been studied in protein isolate systems, to the best of our knowledge, it has not yet been explored in HPB systems. In this study, we isolated native HPBs using an enzymatic method. Aqueous suspensions of HPBs (4 % protein, w/w) were heated at selected temperatures (60–100 °C) and pH 7 for 20 min, followed by hydrolysis with trypsin at pH 7 and 37 °C for 120 min. The thermal aggregation of proteins in HPBs was characterised using confocal laser scanning microscopy (CLSM) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The hydrolysis of HPBs by trypsin was monitored over 120 min by measuring the degree of protein hydrolysis (DH) and analysing SDS-PAGE. Aggregation of edestin in HPBs, primarily driven by disulfide bond formation, occurred upon heating, most noticeably at temperatures above 80 °C. Heating increased DH and altered protein degradation patterns of both acidic and basic subunits of edestin. This may be related to conformational changes in the HPB structure resulting from heat-induced dissociation-association of multiple HPB protein fractions, including 11S edestin, 7S globulin, and 2S albumin. These findings contribute to our understanding of the structure-hydrolysis relationships of HPBs, potentially leading to their use as a new plant-based material for food applications.