Recycling of bakery wastes using an amylolytic lactic acid bacterium

Abstract

Production of lactic acid from discarded bread by using an amylolytic lactic acid bacterium, Lactobacillus amylovorus, was investigated to recycle bakery wastes. Addition of 2.0% yeast extract in the medium containing 3.58% bread crust caused maximum acid production. The stimulation of lactic acid production by less expensive materials such as corn steep liquor, defatted soybean powder, rice bran and wheat bran at additional levels of 2.0% was also observed, but limited. Acid production in the medium supplemented with 2.0% corn steep liquor was enhanced by the further addition of 2.0% defatted soybean powder and reached the levels comparable to medium containing 1.4% yeast extract. In the medium supplemented with 2.0% corn steep liquor and 2.0% defatted soybean powder, 47.2% of total sugars was converted to dl-lactic acid in 72 h under static incubation. When the baking test was carried out, the bread made with the addition of the culture filtrate was significantly ( P < 0.05) preferred over those with and without addition of commercial fermented seasoning with respect to taste and overall acceptability.