Impact of thawing methods on physico‐chemical properties and microstructural characteristics of concentrated milk

Abstract

This study investigated the effects of different thawing methods on the physicochemical properties and microstructural characteristics of pasteurized milk and concentrated milk. Four thawing methods including air thawing, flowing water thawing, microwave thawing, and ultrasonic thawing (UT) were individually used. The results showed that particle size and fat globules size of milk increased after thawing, but UT could improve these conditions. For the pasteurized milk, thawing process caused ethanol stability and heat stability degradation. Thawing decreased thermal stability of concentrated milk; however, no change was observed in ethanol stability.Secondary structures of proteins in both samples were also destroyed after thawing.The thawing method did not change pH values, but it would cause a small change in titratable acidity. Overall, the UT could maintain physico-chemical properties of pasteurized milk and concentrated milk better compared with other thawing treatments.

Effects of Low-Frequency Electromagnetic Field on the Physicochemical Properties of Freeze–Thawed Mongolian Cheese

“…However, the heating process of microwave thawing affected the stability of the protein in the E-M-0 group. Similarly, denatured proteins expose more sites for hydrolase action, which may be the main reason for their higher free amino acid content than that of the CK group [ 24 , 25 ]. With the extension of storage time, the total amount of free amino acids of all groups showed an upward trend, indicating the normal post-ripening behavior of cheese under frozen storage [ 26 ].…”