Department of Food Science and Nutrition, University of Minnesota , 1334 Eckles Avenue, St. Paul, Minnesota 55108, United States.
J Agric Food Chem. 2013 Sep 11;61(36):8676-86. doi: 10.1021/jf402631y. Epub 2013 Aug 28.
Quality loss in intermediate-moisture foods (IMF) such as high-protein nutrition bars (HPNB) in the form of hardening, nonenzymatic browning, and free amino group loss is a general concern for the manufacturers. To measure the extent of quality loss over time in terms of these negative attributes, through changing the ratio by weight between two commercial spray-dried hen egg powders, egg white (DEW) and egg yolk (DEY), the storage stability of 10 IMF systems (water activity (aw) ∼ 0.6) containing 5% glycerol, 10% shortening, 35% protein, and 50% sweetener (either maltitol or 50% high-fructose corn syrup/50% corn syrup (HFCS/CS)) were studied. Additionally, the storage stability of the DEY powder itself was investigated. Overall, during storage at different temperatures (23, 35, and 45 °C), the storage stability of DEY in dry and IMF matrices was mainly controlled by the coaction of three chemical reactions (disulfide bond interaction, Maillard reaction, and lipid oxidation). The results showed that by replacing 25% of DEW in an IMF model system with DEY, the rate of bar hardening was significantly lower than that of the models with only DEW at all temperatures due to the softening effect of the fat in DEY. Furthermore, the use of maltitol instead of HFCS/CS in all bar systems not only resulted in decreased hardness but also drastically decreased the change in the total color difference (ΔE*). Interestingly, there was no significant loss of free amino groups in the maltitol systems at any DEW/DEY ratio.
中间水分食品（IMF），如高蛋白营养棒（HPNB），会出现硬化、非酶褐变和游离氨基损失等质量损失问题，这是制造商普遍关注的问题。为了衡量这些负面属性随时间推移的质量损失程度，通过改变两种商业喷雾干燥鸡卵蛋白粉（蛋清（DEW）和蛋黄（DEY））之间的重量比，研究了 10 种 IMF 系统（水分活度（aw）约为 0.6）的储存稳定性，这些系统含有 5%甘油、10%起酥油、35%蛋白质和 50%甜味剂（麦芽糖醇或 50%高果糖玉米糖浆/50%玉米糖浆（HFCS/CS））。此外，还研究了 DEY 粉末本身的储存稳定性。总体而言，在不同温度（23、35 和 45°C）下储存时，DEY 在干燥状态和 IMF 基质中的储存稳定性主要受三种化学反应（二硫键相互作用、美拉德反应和脂质氧化）的共同作用控制。结果表明，在 IMF 模型系统中用 DEY 替代 25%的 DEW，可以显著降低所有温度下模型的棒硬化速率，这是由于 DEY 中的脂肪具有软化作用。此外，在所有棒系统中使用麦芽糖醇代替 HFCS/CS，不仅降低了硬度，还极大地降低了总色差（ΔE*）的变化。有趣的是，在任何 DEW/DEY 比例下，麦芽糖醇系统中游离氨基都没有明显损失。
