Abstract: Fresh Jincheng orange juice was treated by high-temperature instantaneous method (93 ℃, 30 s), low-temperature and long-time method (70 ℃, 15 min) and the method (80 ℃, 10 min) commonly used by domestic enterprises in order to study the effects of different heat sterilization methods on the quality of orange juice. Physio-chemical characteristics including juice color, pH, total soluble solids (TSS), titratable acidity (TA), VC, organic acids, reducing sugars and microbiological indexes of Jincheng orange juice were determined. At the same time DNA integrity was preliminarily studied. The results showed that both high temperature and long heating time had an unfavorable effect on orange juice, the contents of VC and organic acids decreased and genomic DNA integrity was significantly impaired. Based on the data obtained, it can be concluded that treatment at 80 ℃ for 10 min is better than the other two in maintaining the quality of orange juice.

Key words: sterilization method, orange juice, quality, physio-chemical characteristics, DNA degradation