Upcycling brewers’ spent grain for functional food development and the effect on markers of cardiovascular disease risk in healthy adults

Date

5/12/2021

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Abstract

Brewers’ spent grain (BSG) is the leftover grain from beer production that contains protein, fiber, and minerals. This dissertation includes three separate studies. First, whole grain versus refined grain consumption patterns and interest in BSG-enriched foods was determined. College student focus groups (n = 37; 92% female; 18-45 y) indicated that whole grain consumers would most likely consume BSG-containing foods, education of BSG health benefits and sensory attributes are necessary for purchasing decisions, and handheld baked goods/snacks are ideal BSG foods. Second, consumer acceptance testing was conducted in adults (n = 107; 86% female; 18-60 y) to evaluate muffins containing 7.5 g BSG (20% wt:wt flour), 11.2 g BSG (30% wt:wt flour), and 0 g BSG (control) on overall liking, appearance, texture, moistness, sponginess, and taste. Appearance (p = .001) and taste (p = .008) were significantly different across all muffins. Muffins with 20% BSG received higher appearance and taste ratings than 30% BSG muffins, but all muffins maintained acceptability. Muffins containing 30% BSG were chosen for the diet intervention because they maintained consumer acceptance and provided higher concentrations of BSG. Lastly, BSG’s impact on cardiovascular disease (CVD) risk factors were determined in healthy adults (n = 37; 26 ± 4 y; BMI 23 ± 3 kg/m2) using a randomized, controlled study. Participants consumed muffins with 10.4 g BSG (treatment) or 0 g BSG (control) daily for 8 weeks. Fasting blood was collected for lipids, glucose, insulin, and inflammatory markers, and body composition was assessed using air displacement plethysmography at baseline and 8-weeks. Participants recorded dietary intake, gastrointestinal symptoms and bowel habits, and daily muffin consumption. Mixed-design 2-way ANOVA examined between- and within-group differences. Dietary fiber intake increased in the BSG group (p = .003) and both groups demonstrated good compliance, but there were no significant effects on lipids, glucose, insulin, inflammatory markers, body composition, or blood pressure. In conclusion, focus groups demonstrated interest in consuming BSG-enriched baked goods/snacks, and 30% BSG muffins maintained consumer acceptability, but despite increased fiber intake and BSG muffin tolerance, daily consumption of 10.4 g BSG did not impact CVD risk factors in healthy adults.

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Keywords

Brewers' spent grain, Cardiovascular disease, Functional foods, Fiber, Whole grains, Barley, Sustainability, Food waste, Focus groups, Consumer acceptability studies, Sensory analysis

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