Abstract
We investigated the effects of heating on the milk-like aroma which is one of pleasant aromas characteristic to raw cow's milk. The strength of the milk-like aroma of market milk from Holstein cows was in the following order: low temperature long-time (63°C, 30min) heated milk>high-temperature short-time (75°C, 15sec) heated milk>ultra high-temperature (120°C, 3sec) heated milk. The strength of the body (kokumi) evaluated on opening the naris was the same order as that of the milk-like aroma, while there was no difference on closing the naris. Thus, the milk-like aroma seemed to give kokumi to milk. The experiments where raw milk was heated under various conditions, and raw and heated milk were fractionated revealed the following facts : The milk-like aroma is assumed to be located predominantly in the milk fat globule membrane. The milk-like aroma is completely kept when heated at 63°C for 30min, partially kept when heated at 75°C for 15 sec and completely lost when heated at 120°C for 3 sec. Preincubation of raw milk at 63°C for 30min make the milk-like aroma resistant to heat-treatment at a temperature higher than 63°C.
