Abstract:

The effects of degree of maturity (DM) of fruit, squeezing way, enzymatic treatment and storage temperature on the cloud stability of orange juice were investigated. As fruit DM increased, the turbidity of squeezed orange juice showed an increasing trend. Micronization by a colloid mill could improve the release of pectin and soluble pectin from fruit pulp, resulting in a significant increase in pectin content in fruit juice (P ＜ 0.05). Pectinesterase presence had notable effect on the cloud stability of orange juice, so this enzyme should be inactivated. Pectinase treatment damaged the cloud stability of orange juice, while the effect of papain treatment was unobvious. No significant change (P ＞ 0.05) was observed for orange juice quality during storage at 4 or 15 ℃, but the turbidity of orange juice decreased significantly during storage at 25 ℃ (P ＜ 0.05). Ambient temperature storage was unbeneficial for the cloud stability of range juice.

Key words: orange juice, maturity, storage, cloud stability