Enzymes produced by solid state fermentation of agro-industrial by-products release ferulic acid in bioprocessed whole-wheat breads

Abstract

Solid-state fermentation (SSF) presents low cost and the possibility of adding value to waste by generating products rich in enzymes. The production of enzymes by SSF and its application in bakery have been previously reported separately in the literature. However, very few studies combine both approaches to evaluate the feasibility of applying enzymes produced by SSF to bread processing. The objective of this study was to use cocoa bean shell (CBS), wheat bran (WB) and brewer's spent grain (BSG) for enzyme production by SSF, and to evaluate their addition in breads. Three breads were produced: control bread (CB), bioprocessed bread added with fermented wheat bran (WBB) and bioprocessed bread added with fermented BSG (BSGB). Feruloyl esterase highest activities were 1,730 mU/g for WB fermented for 24 h and 1,128 mU/g for BSG fermented for 72 h. Xylanase highest activities were 547.9 U/g for BSG fermented for 48 h and 868.1 U/g for WB fermented for 72 h. CBS showed the lowest enzymatic activities. Bioprocessing breads with fermented WB and BSG led to an increase in soluble ferulic acid of 159% and 198%, respectively. The combination of SSF enzyme production and bread enzymatic bioprocessing strategies proved to be an effective green option for the valorization of agro-industrial by-products and the production of breads with enhanced ferulic acid content.

Keywords: Bioprocessing; Enzymes in breadmaking; Feruloyl-esterase; Phenolic compounds; Whole-wheat bread; Xylanase.