Nonenzymatic Browning of Lactose and Caseinate during Dry Heating at Different Relative Humidities

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• 作者：Geoffrey Ge Pan ; Laurence D. Melton
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2007
• 出版时间：November 28, 2007
• 年：2007
• 卷：55
• 期：24
• 页码：10036 - 10042
• 全文大小：145K
• 年卷期：v.55,no.24(November 28, 2007)
• ISSN：1520-5118

文摘

Dry mixtures of lactose and caseinate were heated at 60 °C for up to 96 h at different relative humidities (RHs) ranging from 29 to 95%. The resulting nonenzymatic browning was studied by determining lactulosyl lysine formation in the caseinate (as measured by the conversion to furosine), amount of reacted lactose, loss of lysine, color formation, and fluorescent intensity. For each measurement, the maximum reaction occurred at intermediate RHs. While there is general agreement between the results obtained by different methods, discrepancies are understandable given the complex nature of nonenzymatic browning. It was shown that the degradation of the Amadori product, lactulosyl lysine, increased with RH. Moreover, the Maillard reaction, as opposed to caramelization of lactose, was the major pathway at all RHs. Visible browning occurred when the destruction of Amadori product became dominant, and interactions between sugar fragments and caseinate were not the rate-limiting steps in the nonenzymatic browning.