engleski

Characteristics of barley sourdough during frozen storage

The goal of this study was to determine the impact of freezing conditions and frozen storage time on barley sourdough properties. In this study barley sourdough was fermented by Lactobacillus reuteri or Weissella cibaria with or without sucrose addition. Sourdough was frozen by immersion or blast freezing and stored for four weeks at -18°C. Barley sourdough (20% at dough basis) or native barley flour was mixed with semi-white wheat flour to determine its leavening ability by rheofermentometer at 30°C for 3 h. Cell counts of sourdough bacteria were reduced by 1-2 log in both freezing processes and additionally during storage. In average, sourdough had total titrable acidity 15 ml of 0.1 N NaOH and pH 3.8 independently on starter, sugar addition, and freezing conditions. Farinograph consistency of composite bread doughs was 520 ± 20 BU at maximum and 480 ± 20 BU at the end of 8 min mixing. Development of composite bread dough with sourdough was in average 30 mm compared to 18 mm with native barley flour. Maximum height of developed composite dough was significantly (p<0.05) improved by sucrose addition (+5%) and diminished with storage time (-9% in 4 weeks) of sourdough. Maximum height of gaseous production significantly decreased (-32%) with sourdough storage during four weeks. The results indicate that barley sourdough fermented with either of the cultures could be frozen stored for four weeks and reactivated or directly used in bread making. Composite barley bread would be intended for consumers that want functional bakery products, since whole grain barley is a source of β-glucan.

barley sourdough ; leavening ; rheofermentometer ; acidity ; frozen storage

This scientific work was supported by the Croatian Science Foundation project VH/VT Hrana (Vacuum cooling in prolonged shelf life food production ; project number 09.01/279).