Impact of new ingredients obtained from brewer's spent yeast on bread characteristics

The impact of bread fortification with beta-glucans and with proteins/proteolytic enzymes from brewers' spent yeast on physical characteristics was evaluated. beta-Glucans extraction from spent yeast cell wall was optimized and the extract was incorporated on bread to obtain 2.02 g beta-glucans/100 g flour, in order to comply with the European Food Safety Authority guidelines. Protein/proteolytic enzymes extract from spent yeast was added to bread at 60 U proteolytic activity/100 g flour. Both beta-glucans rich and proteins/proteolytic enzymes extracts favoured browning of bread crust. However, breads with proteins/proteolytic enzymes addition presented lower specific volume, whereas the incorporation of beta-glucans in bread lead to uniform pores that was also noticeble in terms of higher specific volume. Overall, the improvement of nutritional/health promoting properties is highlighted with beta-glucan rich extract, not only due to bread beta-glucan content but also for total dietary fibre content (39% increase). The improvement was less noticeable for proteins/proteolytic enzymes extract. Only a 6% increase in bread protein content was noted with the addition of this extract and higher protein content would most likely accentuate the negative impact on bread specific volume that in turn could impair consumer acceptance. Therefore, only beta-glucan rich extract is a promising bread ingredient.