Fortification of milk fat flavor with milk lipase system

Research Project

Project/Area Number	62560276
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	畜産化学
Research Institution	Faculty of Agriculture, Hokkaido University
Principal Investigator	SAITO Zenichi Faculty of Agriculture, Hokkaido University, 農学部, 教授 (80003424)
Project Period (FY)	1987 – 1988
Project Status	Completed (Fiscal Year 1988)
Budget Amount *help	¥1,500,000 (Direct Cost: ¥1,500,000) Fiscal Year 1988: ¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1987: ¥1,100,000 (Direct Cost: ¥1,100,000)
Keywords	lipase / milk fat / free fatty acids / low-fat cheese / cheese flavor / buttermilk / 脱脂乳 / 均質化 / 生乳 / クリーム
Research Abstract	Free fatty acids liberated from milk fat by the milk lipase system may give a kind of good natural milk flavour to high fat dairy foods. This study was performed to increase the free fatty acids in raw milk by treatment in a Waring blender and a milk homogenizer, and their application for manufacture of low-fat cheese was investigated. Homogenization of raw milk by Waring blender attained a 25-fold increase in lipolysis. The rate of lipolysis was 3-5 times higher in the first one hour immediately after homogenization than in the subsequent one hour period. The efficiency of the Waring blender as evaluated by lipolysis, decreased with the increase in milk fat content. The treatment by Waring blender was effective both at 0゜C and 40゜C, but the effect of a homogenizer used in dairy plants appeared only at 40゜C. a homogenizing pressure of 70 kg/cm^2 was sufficient to achieve maximum increase in free fatty acids. The low-fat cheese, which contained 40-47% moisture and 11-13% milk fat after ripening at 12゜C for 4 months, showed open texture and hard bodies but was easy to grate. The free fatty acids contents (ADV) of the low-fat cheese varied depending on salt content. The ADV values were 70-100 in the low-fat cheese with 1.6% salt, but only 15-25 in those of higher salt content. The low-fat cheese in which homogenized milk replaced non-homogenized or homogenized milk after pasteurization showed very low ADV value , less than 10. The cheese manufactured from the mixture of 10 kg of homogenized milk, 20 kg of buttermilk and 70 kg of skim milk resulted in an elevation in moisture content up to 51% with insufficient cohesion of curd. The low-fat cheese can be used as a raw material for powdered cheese and flavouring additives for foods.