Abstract:

Fruits of 18 longan cultivars were analyzed for physical and chemical parameters, total antioxidant capacity, soluble protein and total phenolics. Results showed that there were remarkable differences in fruit juice rate, contents of total soluble solids and total acids, edible pulp rate and ratio of sugars to acids of tested longan cultivars. Fruit juice rate ranged from 36.02% to 55.74%, and the highest was exhibited in Shuiyan cultivar (55.74%) and the lowest in Hualuguangyan (36.02%).Total soluble solids content ranged from 11.3% to 21.77%, and the highest was exhibited in Baihuamu (21.77%) and the lowest in Qingkebaoyuan (11.3%). Besides, notable differences were also observed in PPO and POD activities and color stability of these longan cultivars. PPO ranged from 0 to 6.6 U, and POD from 72.7 to 1816.7 U. Longan fruits exposed to 30 ℃ and 100 ℃ revealed a total color difference (ΔE) value ranging from 0.24 to 3.68 and from 7.62 to 63.53, respectively. It was preliminarily evaluated that Shixia, Chuliang, Baihuamu, Hualuguangyan and Shuangzimu were excellent cultivars for longan juice and longan wine making. Among these longan cultivars, Shuangzimu and Qingkebaoyuan exhibited the highest and lowest total antioxidant capacity of 20.39 mmol/L and 3.73 mmol/L, respectively. Soluble protein content was fluctuated in the range of 45.82 (Jiluanyan) to 88.8 mg/L (Shixia). The highest total phenolics content valued at 749.95 mg/L was observed in Hualuguangyan, and the highest at 13.02 mg/L in Jiluanyan.

Key words: longan, cultivars, processing characteristics