Pasteurization Efficiency and Physico-chemical Changes of Soymilk HTST Pasteurized Using Microwaves

두유의 마이크로파 고온단시간 살균시 살균효과 및 이화학적 성분 변화

  • Kim, Suk-Shin (Department of Food Science and Nutrition, The Catholic University of Korea) ;
  • Lee, Joo-Hee (Department of Food Science and Nutrition, The Catholic University of Korea)
  • 김석신 (가톨릭대학교 식품영양학과) ;
  • 이주희 (가톨릭대학교 식품영양학과)
  • Published : 1999.10.31

Abstract

This work was to determine the microbial and physico-chemical changes of HTST-pasteurized soymilk using microwave energy. Soymilk was HTST pasteurized$(at\;90^{\circ}C\;for\;20\;sec)$ by three methods: by heating in a stainless steel tube immersed in a hot water bath(MP0), by heating in a microwave cavity to a defiled temperature and then holding in a hot water bath(MP1), and by both heating and holding in a microwave cavity(MP2). The microbial quality based on the total plate count was in the order of MP0, MP2 and MP1. The three samples pasteurized by different methods showed the similar microbial quality with respect to the coliform count, psychrotrophic bacterial count and phosphatase activity. The destruction of trypsin inhibitor was in the order of MP0, MP1 and MP2. There were no significant differences in pH, titratable acidity, viscosity and vitamin $B_2$ content before and after pasteurization and among the different pasteurization methods. The similar or higher quality retention of the MP1 or MP2 supports the possibility of using microwave energy for the HTST pasteurization of soymilk and other fluid food products.

Keywords

soymilk;microwave;HTST pasteurization;microbial destruction;physico-chemical changes