Screening of enzyme activities for improvement of bread quality by potato peel addition to the yeast growth medium

Abstract

Bread staling is defined as physicochemical changes in bread during storage, which results in undesirable changes in bread quality. It has always been one of the serious problems of the industrial sector throughout history. At the same time, vegetable waste, including potato peel (PP), is considered a serious problem to the environment. For this reason, PP has been used in this study to increase enzymatic activities of the yeast Saccharomyces cerevisiae, considered to have positive effects on bread quality. The goal of this study is to design a microbial system to facilitate human activities in industry, both joining the production of valuable enzymes by yeasts and recycling PP in the same medium. As a result, in our study, the highest growth rate of S. cerevisiae was recorded in the treatment with 2% PP present in the yeast growth medium. Also, no microbial growth, from baked bread samples, was observed due to proper storage of the loaves of bread in closed nylon bags at 4 °C for the duration of ten days. Moreover, treatments with 4% PP increased cellulase and invertase activities significantly (P < 0.05), in comparison to treatments with no peel and with 2% peel. While amylase activity has been increased significantly (P < 0.05) in treatment with 2% peel. In conclusion, treatment with 4% peel is recommended for improving enzymatic activity, in general, and bread quality in particular.