Effects of freezing pretreatment on water migration and retrogradation properties of brown rice cake prepared from thermal stabilized rice bran

Abstract

Brown rice cake (BRC) is one of the traditional whole grain foods. This study mainly investigated the effect of freezing pretreatment (−20, −40 and −80 °C for 120 min) and different thermal stabilized rice bran on water distribution and migration, starch retrogradation and microstructure of BRCs. The results showed that the low temperature freezing pretreatment (−80 °C) of BRC containing stabilized rice bran could synergically enhance the binding ability of BRC with water molecules during freezing storage, and significantly increase the content of tightly bound water in BRCs. It was found that the lower temperature freezing pretreatment (−40 and −80 °C) for BRC and the presence of thermal stabilized rice bran in BRC could synergically retard the retrogradation of starch in BRCs, reduce the order of short-range structure in starch, and inhibit the recrystallization of starch. The microstructure results confirmed that lower temperature freezing (−40 and −80 °C) effectively limited the growth of ice crystals and greatly maintained the integrity of the internal structure of BRCs with different thermal stabilized rice bran. Therefore, the combination of thermal stabilized rice bran and low temperature rapid freezing is promising to obtain high-quality BRCs.