不同采收期对‘东红'猕猴桃果实贮藏性、品质和响应低温的影响

Effects of different harvest times on storage performance, quality and response to low temperature of kiwifruit ‘Donghong'

关键词:  猕猴桃, 采收, 贮藏, 果实品质, 软化, 低温

Key words:  kiwifruit, harvest, storage, fruit quality, softening, low temperature

摘要:

为明确不同采收期对红心猕猴桃新品种‘东红'果实成熟度、贮藏性、软熟品质和响应低温的影响,该研究以湖北省丹江口市生产的‘东红'猕猴桃为材料,于盛花期后125～181 d设置9个采收期(H1-H9)。将果实置于1 ℃下贮藏16周,分析不同采收期对果实成熟度、软化速率、贮藏病害和软熟品质的影响,并将果实分别置于1、5、10、20 ℃下贮藏7 d,分析不同采收期对果实响应低温的影响。结果表明:(1)H1-H6果实成熟度相近,H7-H9果实进入晚熟阶段,软化进程显著加快,除H1和H2外,各采收期果实干物质含量无显著性差异。(2)采收期显著影响低温贮藏过程中的果实软化进程,早采(H1-H3)果实的硬度曲线呈典型S型(缓慢-快速-缓慢),而中、晚期果实则为不完整S型。(3)果实硬度降至9.81 N可食用水平所需时间随采收期推迟从H1的15周缩短至H9的3周。(4)除早采(H1-H3)果实腐烂率(5.0%～16.5%)较高外,其他采收期果实腐烂率基本处于1.0%～2.0%之间。(5)不同采收期对软熟后果实可溶性固形物含量、总糖、总酸、固酸比和糖酸比等指标整体无显著影响,而维生素C含量随采收期推迟逐渐下降。(6)不同采收期果实均能响应10 ℃低温诱导而加速软化,但此响应能力随采收期推迟至H8-H9时而减弱。综上,‘东红'猕猴桃采收过早(H1-H3)会增加贮藏腐烂风险,过晚(H7-H9)则显著缩短贮藏期,但采收期对软熟后主要风味品质无显著影响。盛花后159～165 d(果实硬度约55 N)是其快速软化的临界点,建议在此临界点前采收,并结合10 ℃处理可实现果实快速后熟。

Abstract:

In order to elucidate the effects of different harvest times on fruit maturity, storage performance, eating quality, and response to low temperature of the new red-fleshed kiwifruit cultivar ‘Donghong', the fruits of ‘Donghong' grown in Danjiangkou City, Hubei Province, were harvested at nine different times(H1-H9), ranging from 125 to 181 days after full bloom(DAFB)in this study. One group of the fruit was stored at 1 ℃ for 16 weeks to evaluate the effects of different harvest times on fruit maturity, softening rate, storage disorder, and soft ripening quality. Another group of the fruit was stored at 1, 5, 10, 20 ℃ for 7 days to assess the influence of different harvest times on the fruit's response to low temperature. The results were as follows:(1)The fruit from H1 to H6 exhibited similar early maturity at harvest, whereas those from H7 to H9 had an advanced maturity, with the fruit being in a rapid softening phase. However, no significant difference in dry matter content were observed among each harvest time except between H1 and H2.(2)Harvest time significantly affected fruit softening process during cold storage. The early-harvested(H1-H3)fruits displayed a typical sigmoidal softening curve with three distinct phases(slow-fast-slow), while the mid- and late-harvested fruits showed an incomplete sigmoidal curve with only one or two softening phases.(3)The time taken for fruit firmness to reach the edible threshold(9.81 N)decreased significantly with delayed harvest, from 15 weeks for H1 to 3 weeks for H9.(4)Only the early-harvested(H1-H3)fruits exhibited a relatively high rot rate(5.0%-16.5%), while the rates for all other harvest times were within the range of 1.0%～2.0%.(5)Harvest time had no significant overall effect on indicators, such as soluble solids content(SSC), total sugar, total acidity, SSC/acidity, and sugar/acidity in ripe fruit, while vitamin C content progressively declined with delayed harvest.(6)The capacity of fruit to respond to 10 ℃ low-temperature induction with accelerated softening was evident across different harvest times, but this capacity weakened in the H8-H9 fruits with delayed harvest. In conclusion, harvesting ‘Donglong' kiwifruit too early(H1-H3)increases the risk of storage rot, while harvesting too late(H7-H9)significantly shortens storage period. However, harvest time has no significant effect on the main flavor quality traits, such as SSC, total sugar, total acidity, and their respective ratios. The period of 159-165 DAFB, corresponding to a fruit firmness of approximately 55 N, represents the critical point for rapid softening. It is recommended to harvest before this critical point and utilize 10 ℃ treatment to achieve rapid post-ripening of the fruits.