The Effect of Upcycled Brewers’ Spent Grain on Consumer Acceptance and Predictors of Overall Liking in Muffins

Abstract

The brewing industry generates large amounts of food waste including brewers’ spent grain (BSG) and leftover malted grains from beer production. BSG compositions can vary but consistently include high levels of protein and fiber. The potential nutritional and health benefits of BSG have sparked recent interest for food fortification. However, the challenges associated with BSG addition can impact food quality due to increases in fiber and protein content and reduction in starch content. Consumer testing was conducted to evaluate muffins containing varying levels of BSG (0, 20, 30% wt:wt flour) to determine the highest acceptable concentration on overall likeability, appearance, texture, moistness, sponginess, and taste attributes. Significant differences were found within appearance (F = 7.728, P = .001) and taste (F = 4.947, P = .008) ratings across all muffins. Control and 20% BSG muffins were rated significantly higher for appearance (6.74 ± 0.18; 6.64 ± 0.18) than 30% BSG muffins (6.11 ± 0.18). Muffins containing 20% BSG (7.15 ± 0.17) received significantly higher taste ratings than 30% BSG muffins (6.56 ± 0.22) and control muffins (6.49 ± 0.19). However, 30% BSG muffins maintained acceptance for all attributes showing higher allowable BSG substitutions than previously reported. Bivariate correlation analyses found that all attributes across each muffin variation were strongly, positively correlated (r > 0.6) with overall likeability excluding appearance (r = 0.359, P < 0.001) and moistness (r = .466, P < 0.001) in control muffins. Significant predictors of overall likeability were appearance (β = 0.088, P = 0.005), texture (β = 0.181, P < 0.001), sponginess (β = 0.226, P < 0.001), and taste (β = 0.494, P < 0.001). Brewers’ spent grain consumer acceptance results will guide the development of test food products for future human diet intervention compliance.

Functional Bread Produced in a Circular Economy Perspective: The Use of Brewers’ Spent Grain

“…Finally, the overall quality of breads was positively correlated with a malty smell (0.68) and crumb saltiness (0.70), and negatively correlated with ash and IDF% (−0.72 and −0.52), and with crumb fibrousness and porosity (−0.56 and −0.58). Our results were only partially in agreement with the findings of Ktenioudaki et al [16], who found that taste and texture were the attributes that mostly affected the overall acceptability, and with the results of Combest and Warren [74], who found significant correlations only between taste and overall liking. In fact, in our study, some smell, taste, and texture attributes are correlated with the overall sensory quality of breads.…”

Spent Grain: A Functional Ingredient for Food Applications

“…The high fiber content helps in the elimination of cholesterol and fats and improves symptoms of ulcerative colitis [ 31 , 33 , 34 , 35 , 36 ]. Reusing spent grain as a value-added food source for human consumption is appealing because it increases the protein, fiber, vitamin and mineral contents while decreasing the starch and caloric content in grain-based products [ 40 ].…”

“…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. Furthermore, nutrient content could be mentioned on the labels of muffins with 20% and 30% spent grain, both of which are considered “good sources” of protein and fiber, because the portion size contains more than 10% of the recommended daily value of each nutrient [ 40 ].…”