The effects of frozen storage on the Physico-chemical characteristics of bread prepared using yeast isolated from different plant sources

This study was conducted to determine the effects of frozen storage on the physico-chemical characteristics of bread fermented by yeast isolated from different sources pineapple (moris), papaya (sekaki), bamboo shoot (buluh minyak), palm sap and commercial yeast. The leavening ability of yeast in bread dough after 7 days stored at freezing temperature (-18 degrees C) was determined. The results showed that frozen storage of bread dough at -18C decreased the specific volume for all samples. However, yeast isolated from bamboo shoot produced higher (p<0.05) specific volume of bread than the control. On the other hand, the percentage of weight loss of bread showed an increasing trend after storage. Bread prepared using yeast from palm sap showed highest weight loss compare to commercial baker yeast. Frozen storage causes increased in the percentage of the crust moisture content and produce softer crust texture with the exception of bread prepared using yeast isolated from palm sap. On contrary, the moisture content of bread crumb showed a decreased after freezing and produced harder crumb texture. Bread containing yeast isolated from bamboo shoots had the softest breads crumb after freezing. The result suggested that Yeast from bamboo shoot produce best physico-chemical properties of bread after frozen storage. Thus, bamboo shoot yeast has the potential to be used as leavening agent for bread making.