Impact of Microfiltration on Particle Size Distribution, Volatile Compounds and Protein Quality of Pasteurized Milk during Shelf Life

Abstract

The effects of microfiltration on particle size, volatiles, protein quality and proximate compositions in pasteurized milk were studied over 7 days at 4°C. Changes in proximate compositions, pH, particle size, amino acids and volatile compounds of microfiltered and pasteurized milk (MPM) and pasteurized milk (PM) were evaluated. The MPM had lower values of proteins and total solids, and possessed higher particle size compared with PM. The D10 and D50 in MPM were individually reduced by 8.3% and 3.1% from day 0 to 7, and there were no differences for the D90. Sixty-one and 65 compounds were identified in the MPM and PM, respectively. The total contents of aliphatic hydrocarbons and alcohols in MPM decreased with storage length, while those of hydrocarbons, ketones, phenols, nitrogenous compounds and sulfide in PM increased with storage time. Other compounds clearly started to increase on day 4 and were reduced markedly by day 7. After 7 days, aliphatic hydrocarbons and alcohols decreased by 21.8% and 47.3% in MPM, while hydrocarbons, ketones and sulfide increased by 57%, 5.4% and 35.4% in PM, respectively. At the same storage time, the hydrocarbons, alcohols, aldehydes, acid and ketones were less in MPM than in PM. MPM had higher EAAI, BV and ePER values. These highlighted that microfiltration changes the compositions of volatiles and improves protein quality and stability during MPM shelf life.