Effect of Lenient Steam Injection (LSI) heat treatment of bovine milk on the activities of some enzymes, the milk fat globule and pH

Abstract

This study investigated the effects of Lenient Steam Injection (LSI) treatment at temperatures 70–150 °C on the enzymatic activities of the indigenous milk enzymes alkaline phosphatase, lactoperoxidase (LPO), xanthine oxidase (XO), lipoprotein lipase (LPL) and plasmin in comparison with two reference heat treatments of 63 °C for 30 s and of 72 °C for 15 s by indirect heating. Milk fat globule (MFG) size distributions and pH were also monitored. Alkaline phosphatase, LPO, XO and LPL activities decreased with increasing LSI temperature. Plasmin activity was increased at temperatures <80 °C and decreased at temperatures above 90 °C. Milk fat globule homogenisation was observed at temperatures above 110–130 °C.

Quantitative Lipidome Analysis of Boiled Chicken Egg Yolk under Different Heating Intensities

“…Lipid hydrolysis induced by endogenous lipase was also reported in other foods during heating. For example, phospholipases in pork and cow’s milk have a higher activity below 60 °C, which induces more phospholipids to undergo hydrolysis [ 41 , 42 ].…”

The effect of direct and indirect heat treatment on the attributes of whey protein beverages

“…In direct heating systems, almost instantaneous heating is achieved due to the mixing of the heating medium and product. This method involves a more efficient and rapid rate of heat transfer than indirect heating, as it makes use of the latent heat of evaporation as the steam condenses, resulting in reduced residence time and a lower thermal load imparted on the product (Britz & Robinson, 2008;Datta, Elliott, Perkins, & Deeth, 2002;Dickow, Nielsen, & Hammershøj, 2012b;Karayannakidis et al, 2014;Lee, Barbano, & Drake, 2017).…”