Browsing by Author "Hodgkinson S"

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    Amino acid requirements of the infant: the amino acid composition of human breast milk
    (Frontiers Media S.A., 2024-09-17) Moughan PJ; Deglaire A; Yan Y; Wescombe P; Lim WXJ; Stroebinger N; Duan S; Szeto IM-Y; Hodgkinson S; Freitas HR
    The recommended amino acid requirements of the infant are based on the amino acid composition of mature human breast milk. The amino acid composition of breast milk is usually determined following either acid or alkaline (for tryptophan) hydrolysis. For accuracy, however, the known effect of hydrolysis time on amino acid composition should be accounted for. Also, ideally the amino acid composition of breast milk should be given in units of digested (assumed to be absorbed) amino acids. A review of the literature is presented which gives mean total amino acid concentrations in mature human milk (n = 26 studies), mean hydrolysis correction factors (n = 3 studies) and mean true ileal amino acid digestibility coefficients (n = 3 studies, suckling piglet). There were differences between the estimates of amino acid concentration corrected for hydrolysis time and digestibility, and current FAO (2013) recommendations that were not corrected for these factors. The values based on the published literature up until 2023 (mg/g true protein) corrected for hydrolysis time and digestibility gave higher values (more than 16% higher) for leucine, lysine and threonine, and considerably higher values (greater than 30%) for histidine and tryptophan. Current recommendations may need revision.
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    Conformational changes and product quality of high-moisture extrudates produced from soy, rice, and pea proteins
    (Elsevier Ltd, 2024-02) Mao B; Singh J; Hodgkinson S; Farouk M; Kaur L
    This study aimed to investigate the performance of soy, pea, and rice proteins during high-moisture extrusion (HME) to understand better how the plant proteins transform into a fibrous structure. It found that rice protein isolate formed weak structures with the fewest layers and fibrous structures. Extruded pea protein concentrate produced more obviously layered structures than extruded soy and rice samples. Extruded soy protein isolate showed a compact gel structure, whereas extruded soy protein concentrate showed a thin fibrous structure. Meanwhile, the chewiness of soy and pea protein extrudates surpassed that of rice protein extrudates by approximately 10 N. After undergoing HME processing, there was a marked 5–10% decrease in extracted proteins (p < 0.05) in solvents with urea, dithiothreitol, and sodium dodecyl sulphate, when comparing the soy and pea extrudates with their raw materials, except for the extruded rice protein isolate (ERPI) with rice protein isolate. It could be deduced that HME processing promoted the formation of aggregates in soy and pea proteins that the extracted solvents could not dissolve. It also revealed that HME induced an increase in the content of S–S bonds in extruded soy and pea protein but a decrease in ERPI. The percentage of random coils in commercial pea protein, initially at 14.04%, saw a significant increase to 19.36% after extrusion (p < 0.05), indicating that pea protein is more likely to form intermolecular hydrogen bonds. In this study, the secondary structures of rice and soy protein did not show significant changes after extrusion.
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    Effects of Different Protein Sources on Amino Acid Absorption and Plasma Appearance of Tryptophan, Large Neutral Amino Acids, and Tryptophan Metabolites in Pigs
    (Elsevier Inc on behalf of American Society for Nutrition, 2024-07-15) Giezenaar C; Montoya CA; Kreutz K; Hodgkinson S; Roy NC; Mace LJ; Fraser K; Fernstrom JD; McNabb WC; Moughan PJ
    BACKGROUND: Absorption of tryptophan (TRP) across the gut epithelium is potentially modulated by competing large neutral amino acids (LNAAs), which could affect the appearance of TRP and its metabolites in the bloodstream. OBJECTIVES: This study aimed to determine, in a growing pig model of an adult human, the absorption of TRP and other LNAAs from the gastrointestinal tract, and plasma appearance of TRP, LNAAs, and TRP metabolites, in response to dietary proteins varying in TRP content. METHODS: Pigs were adapted for 7 d to each of 4 diets that differed in their protein source and TRP content: 1) alpha-lactalbumin (AL; 9.95 mg TRP/g diet DM), 2) whey protein (6.59 mg TRP/g), 3) casein (3.73 mg TRP/g), or 4) zein (0.14 mg TRP/g). On day 8, pigs were euthanised after a 12-h fast (baseline), or 1, 2, 3, 4, or 6 h after they received a test meal consisting of 45 g protein, or a protein-free meal (n = 6 pigs at each time in each meal group). Tryptophan and LNAA absorption from the small intestine, and appearance of TRP, LNAAs, and TRP metabolites (melatonin, serotonin, kynurenine pathway metabolites), in the portal vein and systemic circulation, were determined. RESULTS: AL intake resulted in sustained elevated plasma TRP concentrations after an overnight fast. The amount of TRP absorbed was dose-dependently related to protein TRP content (P = 0.028), with fastest rates for pigs fed AL (371 mg/h). Portal and systemic plasma TRP, TRP/LNAA, and the TRP metabolites were highest (P ≤ 0.05) after AL intake, and remained above baseline levels for ∼4 h postprandially. Absorption rates of TRP correlated with postprandial plasma TRP and TRP metabolites (P ≤ 0.05). CONCLUSIONS: In adult humans, postprandial plasma TRP and TRP metabolite concentrations can likely be modulated by the TRP content of the meal.
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    Influence of food macrostructure on the kinetics of acidification in the pig stomach after the consumption of rice- and wheat-based foods: Implications for starch hydrolysis and starch emptying rate
    (Elsevier Ltd, 2022-11-15) Nadia J; Olenskyj AG; Subramanian P; Hodgkinson S; Stroebinger N; Estevez TG; Singh RP; Singh H; Bornhorst GM
    How the stomach can serve as a biochemical environment for starch digestion and the implications on starch emptying are not well-understood. Biochemical changes during gastric digestion of cooked wheat- and rice-based diets of varying particle size and microstructure were investigated using a growing pig model. In larger-particle size diets (rice grain, rice noodle, pasta), pH >3 was maintained in the proximal stomach digesta even until 240 min digestion, resulting in extended remaining amylase activity and accumulation of maltose from starch hydrolysis in the stomach. In smaller-particle size diets (couscous, rice couscous, semolina porridge), gastric acidification occurred faster to produce homogeneous intragastric pH and deactivated amylase. The hypothesis of the study was that food macrostructure would impact gastric acidification kinetics, and the resulting biochemical environment for starch hydrolysis in the stomach may further affect the mechanisms of food breakdown in the stomach and gastric emptying of starch.
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    THE EFFECT OF SHOCKWAVE PROCESSING ON MUSCLE PROTEIN STRUC TU RE AND DIGESTIBILITY IN VITRO
    Chian F; Kaur L; Astruc T; Venien A; Loison O; Stubler A-S; Aganovic K; Hodgkinson S; Boland M