采收期对龙眼果实品质和耐贮性的影响

Effects of harvesting date on quality and storability of longan fruit

以福建省主栽龙眼品种油潭本果实为材料 ,研究采收期 (从 8月 19日到 9月 12日每隔 4d采果一次 )对龙眼果实品质和耐贮性的影响。结果表明 :随着采收期的延迟和果实成熟度的提高 ( 8月 19日到 9月 8日采收 ) ,龙眼果皮颜色由青褐色逐渐变成黄褐色 ,果实由近长圆球形逐渐变成扁圆球形 ,果实质量和大小逐渐增加 ,果皮逐渐变薄而果肉逐渐增厚 ,果肉可食率、营养品质和食用品质提高。但过熟的龙眼 ( 9月 12日采收 )果皮变成灰褐色 ,果实品质下降。可用果皮颜色 ,果实质量和大小 ,果皮和果肉厚度 ,果肉可食率、可溶性固形物、总糖、维生素C含量和固酸比值、糖酸比值、食用品质作为确定龙眼果实的采收成熟度参数。供长期贮藏或长距离运输用的龙眼应在 8月 3 1日～ 9月 4日采收 ,在 ( 3 0± 2 )℃下贮藏 8d ,好果率为84.2 4%～ 85 .0 7% ,失重率 3 .0 5 %～ 3 .2 0 % ;在 ( 3± 1)℃下贮藏 40d ,好果率 98%～ 10 0 % ,失重率 0 .2 4%～ 0 .2 6%。

Longan fruit (Dimocarpus longan Lour.) cv. Youtanben, the major cultivar in Fujian Province of China, was used. Effects of harvesting date (harvesting at 4-day intervals from August 19 to September 12) on quality and storability of longan fruit were analyzed. The results were as follows: as fruit harvesting date delayed and maturity increased (i.e. from August 19 to September 8), pericarp color of longan fruit gradually turned from green-brown to yellow-brown, fruit shape turned from approximately long-spherical to oblate-spherical, fruit weight and size gradually increased, pericarp thickness decreased but pulp thickness increased, pulp edibility, nutritional quality and eating quality increased. Whereas pericarp color turned dark-brown, fruit quality decreased when fruit harvested over-mature (i.e. harvesting at September 12). Pericarp color, fruit weight and size, pericarp and pulp thickness, pulp edibility, contents of total soluble solids (TSS), total sugars and vitamin C, ratio of TSS to titratable acidity (TA) or total sugars to TA, and eating quality of pulp were recommended as maturity indices for longan fruit. It was suggested that longan fruit for long-term storage or long-distance transport should be harvested from August 31 to September 4, and the fruit stored at (30±2)℃ for 8 days with 84.2%～85.07% healthy rate and 3.05%～3.20% mass loss, stored at (3±1)℃ for 40 days with 98%～100% healthy rate and 0.24%～0.26% mass loss.