Improvement of chemical composition, physical properties and crystallization characteristics of palm stearin and rice bran oil blends by enzymatic interesterification: Potential base oils in fast-frozen food

Abstract

In order to reduce the enzymatic interesterification cost of base oil in fast-frozen food and improve its physicochemical properties and nutritional value, effects of reaction conditions on the properties of the interesterified fats (IEFs) from palm stearin (PS) and rice bran oil (RBO) were evaluated. The performed conditions were as follows: Thermomyces lanuginosa lipase (TL IM) as catalyst, reaction temperature 50 °C, enzyme load 6%, reaction time 2 h. The IEFs of PS and RBO in different ratios were prepared under these conditions, and their chemical composition, physical properties, and crystallization characteristics were compared with those of the physical blends. Results showed that no trans fatty acids, abundant phytosterols and oryzanol were detected in all the IEFs, suggesting an improvement in nutritive properties. In particular, the IEFs (4:6, 5:5, 6:4, and 7:3, PS:RBO) had relatively low contents of SFA (39.28%–53.01%) and high contents of SUU- and SUS-type TAGs, resulting in lowering slip melting points (35.6–44.9 °C) and good solid fat content range (12.1%–34.3%) at 20 °C with mostly β′ crystals. Thus, this paper provides a simple and low-cost enzymatic interesterification method for preparing high-quality base oil in fast-frozen food.