The influence of carboxymethylcellulose, xanthan and guar-gum addition in bread dough before freezing on metabolism and viability of Saccharomyces cerevisiae

Abstract

Doughs were prepared with different concentrations of carboxymethylcellulose, xanthan, and guar-gum (0.1, 0.2 and 0.3% in doughs), freezed at -20°C and analyzed after 0, 7, 15 and 30 days. Pure Saccharomyces cerevisiae culture was isolated from dough and was cultivated under optimal conditions during 24 hrs to determine the following parameters: specific growth rate, fermentative activities and cytochromes contents in intact cells with the aim of determining the respiration intensity. During freezing of dough for 30 days, the percentage of living cells from dough surface was 53.11% and from the middle 54.95%. Carboxymethylcellulose in concentration of 0.3 and 0.5% increased number of survived cells on the surface to 70.64, and 70.28% and in the middle to 74.79, and 76.54%, respectively. Guar-gum increased number of survived cells only in concentration of 0.1% on the surface to 70.17% and in the middle of the dough to 75.26%. The mean specific growth rate decreased by approximately 10% during 30 days of storage at -20°C. Content of cytochromes in intact cells decreased in all samples during freezing.

Keywords

• Saccharomyces cerevisiae
• frozen dough
• metabolism
• viability