In this work, the protein quality of different bean types after undergoing the preparatory methods of baking, cooking and extrusion was assayed. Protein quality was assessed using a rodent bioassay to evaluate growth and protein digestibility while amino acid composition was determined via HPLC. In vivo protein digestibility was compared to an in vitro assessment method. The average protein digestibility corrected amino acid score (PDCAAS) for processed beans was higher than the digestible indispensable amino acid score (DIAAS) (61% vs. 45%). Extrusion/cooking of Phaseolus varieties resulted in higher PDCAAS (66% on average) and DIAAS values (61% on average) than baked (52% and 48%) while baked faba beans had higher PDCAAS (66%) and DIAAS (61%) values. A significant correlation was found between PDCAAS and in vitro PDCAAS (R2 = 0.7497). This demonstrates which bean processing method will generate the optimal protein quality, which has benefits for both industrial production and individual domestic preparation.

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In order to determine the effect of extrusion, baking, and cooking on the protein quality of yellow and green split peas, a rodent bioassay was conducted and compared to an in vitro method of protein quality determination. The Protein Digestibility-Corrected Amino Acid Score (PDCAAS) of green split peas (71.4%) was higher than that of yellow split peas (67.8%), on average. Similarly, the average Digestible Indispensable Amino Acid Score (DIAAS) of green split peas (69%) was higher than that of yellow split peas (67%). Cooked green pea flour had lower PDCAAS and DIAAS values (69.19% and 67%) than either extruded (73.61%, 70%) or baked (75.22%, 70%). Conversely, cooked yellow split peas had the highest PDCCAS value (69.19%), while extruded yellow split peas had the highest DIAAS value (67%). Interestingly, a strong correlation was found between in vivo and in vitro analysis of protein quality (R = 0.9745). This work highlights the differences between processing methods on pea protein quality and suggests that in vitro measurements of protein digestibility could be used as a surrogate for in vivo analysis.

Blending of protein sources can increase protein quality by compensating for limiting amino acids present in individual sources, whereas processing grain flours by extrusion or baking can also alter protein quality. To determine the effect of baking and extrusion on the protein quality of blended flours from buckwheat and pinto beans, a rodent bioassay was performed and compared to an in vitro method of protein quality determination. Overall, extruded products had higher protein efficiency ratio values, increased digestibility, and greater protein digestibility corrected amino acid score (PDCAAS) values than baked products, with the extruded buckwheat/pinto blend having the greatest PDCAAS value of the experimental diets investigated. A correlation was found between both digestibility and PDCAAS values generated from in vitro and in vivo methods. The use of in vitro digestibility analysis should be investigated as a potential replacement for the current rodent assay for nutrient content claim purposes.

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Chickpea is a widely produced pulse crop, but requires processing prior to human consumption. Protein bioavailability and amino acid quantity of chickpea flour can be altered by multiple factors including processing method. For this reason, the protein quality of processed chickpea flour was determined using in vivo and in vitro analyses for processed chickpeas. Processing differentially affected the protein digestibility‐corrected amino acid score (PDCAAS) of chickpeas with extruded chickpea (83.8) having a higher PDCAAS score than both cooked (75.2) and baked (80.03). Interestingly, the digestible indispensable amino acid score (DIAAS) value of baked chickpea (0.84) was higher compared to both extruded (0.82) and cooked (0.78). The protein efficiency ratio, another measure of protein quality, was significantly higher for extruded chickpea than baked chickpea (p < .01). In vivo and in vitro analysis of protein quality were well correlated (R2 = .9339). These results demonstrated that under certain circumstances in vitro methods could replace the use of animals to determine protein quality.

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Buckwheat (BW) consumption has been linked to improved glycemic control; however, evidence from randomized, placebo‐controlled trials is lacking. Our objective was to assess the post‐prandial response of glucose, insulin and gastrointestinal hormones affecting glycemia and satiety after consumption of BW. Twelve control participants and 12 with type 2 diabetes were recruited and asked to consume crackers containing 50 grams of available carbohydrate made from BW or rice flour, in random order, on two separate occasions. Blood samples were taken 0, 15, 30, 45, 60, 120 and 180 minutes after consumption. Plasma responses of glucose, insulin, C‐peptide, incretin and satiety hormones were assessed using total area under the curve (tAUC). Glucose, insulin and C‐peptide were not affected by BW consumption. There was a trend for tAUC of the incretin hormone glucagon‐like peptide 1 to be higher after BW consumption while paradoxically the tAUC for glucose‐dependent insulinotropic peptide, another incretin hormone, was lower. Although tAUC of ghrelin and peptide YY were not different between rice and BW, there was a trend for tAUC of the anorexigenic hormone pancreatic polypeptide to be higher after consumption of BW. Overall, a food product made from BW containing 50 grams of available carbohydrate does not modify post‐prandial glycemia or insulinemia; however, changes in satiety hormones warrants further study.Grant Funding Source: Manitoba Functional Foods Opportunity Program; Agri‐food Research & Development Initiative; Manitoba Agri‐health Research Network