Energy saving through partial homogenization of milk over conventional milk homogenization

Abstract

The present study was conducted to check the feasibility of partial homogenization of market milk used for the preparation of tea (commonly known as ‘chai’ in India) and thereby estimate the energy-saving potential of the process. In the case of partial homogenization of milk, cream with different fat content (15%, 20%, and 25%) was homogenized at three first-stage pressures viz., 1000 psi, 1200 psi, and 1500 psi while keeping the second-stage pressure constant at 500 psi. The homogenization of milk was conducted at 65°C and 70°Ctemperatures. The homogenized cream was used to preparestandardized milk having 4.5% fat and 8.5% solids-not-fat. The temperature and pressure for homogenization were optimizedbased on the desirable least creaming index of samples of standardized milk at 48 h of refrigerated storage (4±2°C). In the case of conventional homogenization of milk, milk was first standardized to 4.5% fat and 8.5% solids-not-fat and then homogenized at 2000 psi and 500 psi for the first and second stages respectively. Tea was prepared from milk obtained from both the homogenization processes and they were subjected to sensory evaluation. The energy consumption in both cases was measured from the energy meter installed at the homogenizer motor. The study revealed that, without affecting the quality of homogenized milk, about 68% of energy could be saved in partial homogenization of milk as compared to conventional homogenization of milk