Influence of pH and Composition on Nonenzymatic Browning of Shelf-Stable Orange Juice during Storage

• Published in: Journal of agricultural and food chemistry 2020-05, Vol.68 (19), p.5402-5411
• Main Authors: Pham, Huong T. T, Kityo, Paul, Buvé, Carolien, Hendrickx, Marc E, Van Loey, Ann M
• Format: Article
• Language: English
• Subjects: Ascorbic Acid - chemistry; Citrus sinensis - chemistry; Color; Food Storage; Fructose - chemistry; Fruit - chemistry; Fruit and Vegetable Juices - analysis; Hydrogen-Ion Concentration; Maillard Reaction
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.9b07630

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.