Assessment of the functional properties of brewer’s spent grain and consumer perception of functional bread in the city of Аstana

Brewer’s spent grain is one of the most promising by-products of the brewing industry and is characterized by high nutritional value and functional properties. This study presents a comprehensive investigation of the technological characteristics of dried brewer’s spent grain, including the determination of chemical composition, heavy metal content, water-holding capacity, and microstructure of the raw material. The effect of adding dried brewer’s spent grain at levels of 5–35% on the organoleptic properties of bread was evaluated using a sensory heat map. In addition, an online survey was conducted among residents of the city of Astana (N = 109; aged 16–25) to assess consumer attitudes and willingness to purchase functional bread containing secondary processing products. The results were compared with data from a face-to-face survey conducted in 2021 (N = 100). The findings indicate that young people in Astana show a high level of interest in environmentally friendly and functional food products; however, the main barrier is insufficient awareness of the benefits of secondary plant-based raw materials such as brewer’s spent grain. The use of brewer’s spent grain contributes to the reduction of food waste and supports the development of sustainable production. For the first time under the conditions of Kazakhstan, technological and sociological methods for bread evaluation were combined.