Upcycling Brewers’ Spent Grain: The Development of Muffins and Biomarker Response After Consuming Muffins for 8-Weeks in Healthy Adults From Randomized-Controlled Trial

Abstract

Objectives Brewers’ spent grain (BSG), the most abundant by-product of the brewing industry, consist of malted barley residue leftover from beer production and are rich in fiber and protein. This study examined whether regular consumption of upcycled BSG flour can modulate blood biomarkers of cardiovascular disease (CVD), glucose homeostasis, inflammation, and body composition in healthy adults. Methods Muffins containing 7.5 g BSG (20% wt: wt flour), 11.2 g BSG (30% wt: wt flour), and 0 g BSG (control) were developed and tested for consumer acceptability on overall liking, appearance, texture, moistness, sponginess, and taste. BSG muffins that maintained mean ratings of 5 or higher on a 9-point hedonic scale were considered acceptable and included in a feeding trial. A single-blind, randomized, placebo-controlled human feeding trial compared consumption of muffins with 12 g BSG (30%) or 0 g BSG daily for 8 weeks. BSG and control muffins were similar in total calories (BSG: 306 kcal, control: 307 kcal) and available carbohydrates (BSG: 51.2 g, control: 52.0 g). Fasting blood was collected for glucose, insulin, and lipid measurements and body composition was assessed using air displacement plethysmography at baseline and 8-weeks. During the 8 weeks of intervention, participants recorded 3-day food logs, 2-day stool logs to monitor changes in bowel movements and symptoms, and daily muffin consumption. Results Consumer testing (n = 107) found significant differences among appearance (F = 7.728, P = .001) and taste (4.947, P = .008) ratings across all muffins. Control (6.74 ± 1.84) and 20% (6.64 ± 1.90) muffins received higher appearance ratings and higher taste ratings for 20% muffins (7.15 ± 1.72). Additionally, 30% muffins had acceptability. In the feeding trial, 18 participants (26.8 ± 4.0 y) with a BMI of 23.4 ± 3.2 kg/m2completed the study. Systolic blood pressure (BP) (P = .044) and insulin (P = .011) were lower in the BSG group than the control group after consuming study muffins for 8-weeks. There were no significant treatment effects for glucose concentrations or body composition outcomes between test groups or over time. Conclusions Consuming BSG reduces systolic BP and insulin in healthy adults compared to control muffins. A higher BSG dosage or consuming BSG for a longer duration may be necessary to observe additional clinical endpoints. Funding Sources Moore-Khourie Fund.

Application of Agri-Food By-Products in the Food Industry

“…It is a very common practice to add fruit and vegetable by-products to bakery goods including bread, snacks, and biscuits in order to increase their functional features. It is also well recognized that several fruit and vegetable by-products, including carrot peels, beetroot, raspberry, and cranberry pomace, can be used to boost the phenolic and dietary fiber content of baked goods [139][140][141].…”

Use of Brewers’ Spent Grains as a Potential Functional Ingredient for the Production of Traditional Herzegovinian Product Ćupter

“…The addition of BSG can influence the odor, color, texture, and flavor profile of the traditional product, the taste of which is well known to consumers. Therefore, preference testing is necessary to validate consumer acceptance of newly developed ćupter with the addition of BSG [37,38]. The 60 panelists evaluated the four different receipts for ćupter using an 8-point Likert questionnaire scale that covered the preference analysis of color, texture, smell, taste, and general appearance.…”

Spent Grain: A Functional Ingredient for Food Applications

“…This may be because the spent grain has a high fiber content that acts as a thickening agent by absorbing water in the batter. A study of 18 participants who consumed muffins with 30% added spent grain daily for 8 weeks showed beneficial effects associated with reduced systolic blood pressure and insulin compared with the control group [ 63 ]. Another study on the use of spent grain in muffins found that 30% spent grain retains consumer approval and offers more chances of triggering biological reactions due to the higher levels of proteins, fiber and antioxidants.…”