Khamis Ali Omar

Triacylglycerol composition, melting and crystallization profiles of lipase catalysed anhydrous milk fats hydrolysed

ABSTRACT Dairy products remain valuable components of human diet due to their balanced nutritive value and pleasant flavour. In this study, triacylglycerols (TAGs) from anhydrous milk fats were hydrolysed by Lipozyme-435 and Novozyme-435 and later on analysed by using ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Results revealed that the percentages of TAGs (CN 28–34) and TAGs (CN 36–42) with at least two short-chain fatty acids and with short- and medium-chain fatty acids were respectively decreased after 24 h of enzymatic hydrolysis. On the other hand, TAGs (CN 44–54) with at least two long-chain fatty acids were found to increase in both Lipozyme-435- and Novozyme-435-treated anhydrous milk fat (AMF). Meanwhile, the melting and crystallization profiles of both Lipozyme-435- and Novozyme-435-treated AMF were modified and significantly different when compared with the untreated AMF.

Influence of lipase under ultrasonic microwave assisted extraction on changes of triacylglycerol distribution and melting profiles during lipolysis of milk fat

In this study, the use of low irradiation ultrasonic microwave assisted extraction (UMAE) on lipases mixed with anhydrous milk fat (AMF) or anhydrous buffalo milk fat (ABF), with the aim of hydrolyzing triacylglycerols (TAGs), especially those containing short chain fatty acids, is reported. Lipozyme-435, Novozyme-435 and Thermomyces lanuginosus were mixed with phosphate buffer and either AMF or ABF in a jacketed flask. The reaction mixtures were exposed to low irradiation UMAE under temperature control (50 °C ± 2 °C) for 45 minutes. An ultra-performance liquid chromatography (UPLC) system coupled with quadrupole time-of-flight mass spectrometry (Qu-ToF-MS) was used to analyze TAG in AMF and ABF after lipolysis. The re-distribution was evidenced by the presence of a higher percentage of TAGs with at least two medium-chain fatty acids and one long-chain fatty acid, and a high percentage of TAGs with long-chain fatty acids as a consequence of a decreased percentage of TAGs with short-chain fatty acids. Furthermore, the melting and crystallization profiles were modified in both AMF and ABF treated with lipases in comparison to just AMF or ABF.