Fritsch R J, Hoffmann H, Klostermeyer H
Z Lebensm Unters Forsch. 1983;176(5):341-5. doi: 10.1007/BF01057723.
The heat-induced formation of lysinoalanine (LAL) was studied in raw skim milk that had been subjected to heat treatments as is usual in milk technology. Preheat treatment of milk at temperatures below 100 degrees C up to 20 min resulted in neglectable LAL amounts below 10 ppm i.p. (i.p.=in the protein) if at all. Tests with an UHT pilot plant showed that there was no proven formation of LAL with direct UHT-treatment at 110-130 degrees C for 10-25 min. In indirect UHT-treated milk vert small LAL amouints up to 50 ppm i.p. were detected only in those milk samples that were treated at temperatures high than 145 degrees C and holding times longer than 10 s. Autoclave sterilization in the range of 110-129 degrees C/10-25 min induced LAL amounts of 110 to 710 ppm i.p.. LAL formation in autoclave sterilized milk was almost directly dependent on heating temperature and time. Pre-treatment at temperatures below 100 degrees C induced no further LAL formation in any sterilization processes subsequent to preheating. In the pH range 6,50-6,90 LAL amounts in autoclave-sterilized milk increased directly with higher pH values at all temperatures. The varying degree of LAL formation with pH value was substantially more noticeable at higher than at lower temperatures. Increasing of lactose concentration caused only an insignificant decrease in LAL formation in autoclave-sterilized milk.
在生脱脂乳中研究了热诱导赖氨酸丙氨酸（LAL）的形成情况，该生脱脂乳经过了牛奶加工工艺中常见的热处理。在低于100℃的温度下对牛奶进行长达20分钟的预热处理，即便有LAL生成，其含量也可忽略不计，低于10 ppm i.p.（i.p.=在蛋白质中）。超高温瞬时灭菌中试装置测试表明，在110 - 130℃下直接进行超高温瞬时灭菌处理10 - 25分钟，未证实有LAL生成。在间接超高温瞬时灭菌处理的牛奶中，仅在那些处理温度高于145℃且保温时间长于10秒的牛奶样品中检测到了高达50 ppm i.p.的极少量LAL。在110 - 129℃/10 - 25分钟范围内进行高压釜灭菌会诱导产生110至710 ppm i.p.的LAL。高压釜灭菌牛奶中LAL的形成几乎直接取决于加热温度和时间。在低于100℃的温度下进行预处理，在随后的任何灭菌过程中都不会进一步诱导LAL的形成。在pH值6.50 - 6.90范围内，高压釜灭菌牛奶中的LAL含量在所有温度下都随pH值升高而直接增加。在较高温度下，LAL形成随pH值变化的程度比在较低温度下明显得多。乳糖浓度的增加只会使高压釜灭菌牛奶中LAL的形成略有减少。
