The effect of potato peels added to yeast growth medium on themain enzymes involved in bread staling

Bread staling is a term which is used to describe the physicochemical changes of bread during storage, resulting in undesirable changes in bread quality. It has always been one of the industrial burden throughout the history. At the same time, vegetable wastes, including potato peel (PP), is considered as a serious problem to environment. For this reason, PP has been used in this study to increase enzymatic activities of Saccharomyces cerevisiae, considered to have positive effects on bread quality. As a result, the highest growth rate of yeast was recorded in the treatment with 2% PP present in yeast growt medium. Moreover, treatments with 4% PP increased cellulase and invertase activity the most, in comparing to treatments with no peel and with 2% peel. While, amylase activity have been increased most in treatment with 2% peel, in contrast, lipase activity has been suppressed by adding the peel. Regarding bread quality, those which have been made from 4% peel treatment was the most acceptable ones in day 0 and 10, while few staling effects were recorded. Additionally, no effects of partially purified enzyme solutions, which 250 μL was used per 100 g of dough, on bacterial and fungal content of the breads were recorded in both days. The goal of this study is designing a microbial system for facilitating human activities in the industry, both joining the production of valuable enzymes by yeasts and recycling of PP at the same medium.