龙眼果实采后呼吸强度、细胞膜透性和品质的变化

研究了采后福眼龙眼果实在(20±0.5)和(4±0.5)℃温度下的呼吸强度、细胞膜透性和品质的变化.结果表明:龙眼果实属于非呼吸跃变型果实;在(20±0.5)℃下贮藏2d,果实呼吸强度下降,之后明显上升;果实采后果皮细胞膜透性快速增加,果实易失重、衰老、腐烂和果皮褐变,贮藏后期果肉自溶;果肉可滴定酸和VC含量快速下降,总糖和蔗糖含量下降,还原糖含量先升后降,可溶性固形物含量在贮藏前期下降而后期上升,可溶性固形物和可滴定酸比值先升后降;贮藏后期果肉可滴定酸含量增加.而(4±0.5)℃低温贮藏可显著降低果实呼吸强度,抑制病原菌生长,延缓果实衰老和果皮细胞膜透性增加,延迟果皮褐变,减少果实失重和果肉营养成分变化,抑制果肉自溶,保持果实较高的品质,延长果实贮藏期.

Changes of respiration rate, cell membrane permeability and quality in post-harvest longan fruit

The changes of respiration rate, cell membrane permeability and quality in post-harvest longan (Dimocarpus longan Lour.cv.Fuyan) fruit at (20±0.5) ℃ and (4±0.5) ℃ were investigated in this paper. The respiratory pattern of longan fruit belonged to non-climacteric fruit. Fruit respiration rate decreased when longan fruit stored at (20±0. 5) ℃ for 2 days, then respiration rate increased obviously. Cell membrane permeability of longan pericarp increased rapidly, fruit was easy to weight loss, senescence, decay and pericarp browning after harvest. Aril breakdown was observed at the later stage of storing fruit at (20±0.5) ℃. Titratable acidity (TA) and vitamin C contents in longan aril decreased rapidly, total sugars and sucrose contents decreased, and reducing sugars contents increased at the earlier stage of storage but then decreased. Total soluble solids (TSS) content decreased at the earlier stage of storage but increased at the later stage. The ratio of TSS to TA increased at the earlier stage of storage but then decreased. TA content in aril increased at the later stage of storage. Low temperature storage at (4±0. 5) ℃ could decrease markedly fruit respiration rate, inhibit pathogen development, delay fruit senescence and cell membrane permeability of pericarp increase, retard pericarp browning, reduce fruit weight loss and aril nutritional ingredient changes, inhibit aril breakdown, maintain fruit with higher quality and extend storage life of fruit.