Chemical compositions and crystallization characteristics of SOS-rich fats

Abstract

SOS-rich fats have been developed to improve heat stable properties and fat bloom-resistant abilities of chocolates, which is highly connected with their crystallization behaviors. Shea butter stearin (SBS) and mango kernel fat (MKF) are the typical SOS-rich fats. Both contained high levels of stearic acid (45.06%–59.67%) and oleic acid (31.85%–39.97%), while 77.00%–86.88% of the oleic acid were distributed at the sn-2 positions of triacylglycerol molecules, contributing to forming 78.04% of SOS in SBS and 47.85% of SOS in MKF. Their SOS levels were significantly higher than that in cocoa butter (CB, 25.43%). However, MKF contained the highest levels of SOO (15.59%), which was about six to eight times as likely that in SBS and CB (1.76%–2.66%). Further crystallization tests revealed that SBS and MKF exhibited similar rod-like growth from instantaneous nuclei at 4°C. The former was then changed to become more spherulitic growth at 20°C significantly. Specifically, large feather-like crystals corresponding to β form were observed in SBS at the final stage of crystallization at 20 and 30°C, while MKF exhibited smaller crystals. The higher concentration of SOO in MKF was considered as the softening factor. It was further supposed that constant crystallization at 20°C may be difficult for some fats (e.g., SOS < 30%) to form adequate amounts of β crystals. The results will provide information on making cocoa butter blends and chocolate tempering.