Department of Microbial and Molecular Systems (M2S), Laboratory of Food Technology, KU Leuven, Kasteelpark Arenberg 22, Box 2457, 3001 Heverlee, Belgium.
J Agric Food Chem. 2020 May 13;68(19):5402-5411. doi: 10.1021/acs.jafc.9b07630. Epub 2020 May 1.
Nonenzymatic browning during storage of pasteurized shelf-stable orange juice causes a major color deterioration, which negatively affects consumer acceptance of the juice. This study, for the first time, investigated on a kinetic basis the effect of pH and suspected nonenzymatic browning reaction precursors such as ascorbic acid, fructose, and arginine on nonenzymatic browning during accelerated storage (42 °C) using an orange-juice-based model system. The results showed that lowering the pH of the model juice system from 3.8 to 1.5 significantly increased the rate of ascorbic acid degradation, the rate changes (increases and decreases) in different sugars, and the rates of furfural and 5-hydroxymethylfurfural formation. These changes coincided with a higher browning intensity, which became more pronounced toward the end of storage of the juice model system. Similarly, adding more ascorbic acid and fructose largely increased the formation of furfural and 5-hydroxymethylfurfural, respectively, and resulted in a higher browning intensity. In conclusion, lowering the pH of the orange juice or addition of ascorbic acid or fructose will enhance its browning during prolonged storage.
在巴氏杀菌的货架稳定橙汁的储存过程中非酶褐变会导致严重的颜色劣化，从而降低消费者对果汁的接受程度。本研究首次基于动力学研究了 pH 值以及疑似非酶褐变反应前体（如抗坏血酸、果糖和精氨酸）对加速储存（42°C）过程中非酶褐变的影响，使用基于橙汁的模型系统。结果表明，将模型果汁系统的 pH 值从 3.8 降低至 1.5 显著增加了抗坏血酸降解、不同糖的速率变化（增加和减少）以及糠醛和 5-羟甲基糠醛形成的速率。这些变化与更高的褐变强度一致，在果汁模型系统储存结束时变得更加明显。同样，添加更多的抗坏血酸和果糖分别大大增加了糠醛和 5-羟甲基糠醛的形成，并导致更高的褐变强度。总之，降低橙汁的 pH 值或添加抗坏血酸或果糖会增强其在长时间储存过程中的褐变。
