|
The α-lactalbumin(a-la) concentration in raw and laboratory -heated milks by HPLC was 1.20 mg/ml (unheated), 1.17 mg/ml (63 ℃ , 30 min), 1.13 mg/ml (72 ℃ , 15 sec) and 0 mg/ml (100 ℃ , 10 min), respectively. Whereas, α-lactalbumin concentration ranges of commercial milks were 1.00∼1.02 mg/ml (pasteurized), 0.23∼0.68 mg/ml (UHT-pasteurized) and 0.77∼0.89 mg/ml (UHT-sterilized), respectively. It was supposed that the α-lactalbumin content of sterilized milk will be lower than that of UHT milk, but the opposite occurred. This discrepancy would be caused by the different heating system in the milk plants, where indirect UHT-treatment had more heat intensity than direct UHT-processing. The HPLC determination of α-lactalbumin may be an indicator to evaluate correctly and rapidly heated milks.
|