ABSTRACT A hand-held, chlorophyll content meter [the delta absorbance (DA) meter] was used to develop an optimal harvest maturity model for ‘Minneiska’ apples (Malus domestica Borkh). Fruit from four commercial orchards in the Annapolis Valley, Nova Scotia, Canada, were sampled weekly (25 fruit per location) over eight consecutive harvests during the 2011–2013 growing seasons. At each harvest, 60 fruit were measured for their DA value (IAD ), mass, firmness, titratable acidity (TA), soluble solids content (SSC), red skin colouration, starch-to-sugar conversion and internal core ethylene concentration. Following 3–3.5 months of refrigerated air storage at 3.5°C, samples were removed and assessed for fruit bruising, skin greasiness, rot and physiological disorders. Peel chlorophyll content was strongly and positively correlated with epidermal IAD measurements. IAD values declined significantly during fruit ripening and were negatively related to harvest week. The optimal harvest period was identified by aligning ‘at harvest’ IAD , fruit quality and ‘post-storage’ disorder data with the corresponding harvest week. IAD averages associated with harvests having high commercial fruit quality demarcated the optimal harvest boundaries. As the IAD values declined during fruit maturity, the upper boundary value of 0.26 was defined as ‘when to begin harvest’, while the lower boundary value of 0.12 was deemed ‘when to end harvest’ for longer-term storage.

中文翻译：

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基于Δ吸光度计的'Minneiska'苹果果实最佳收获成熟度模型

摘要 手持式叶绿素含量计 [delta 吸光度 (DA) 计] 用于开发“Minneiska”苹果 (Malusdomestica Borkh) 的最佳收获成熟度模型。在 2011 年至 2013 年的生长季节连续八次收获，每周对来自加拿大新斯科舍省安纳波利斯谷的四个商业果园的水果进行采样（每个地点 25 个水果）。在每次收获时，都会测量 60 个水果的 DA 值 (IAD)、质量、硬度、可滴定酸度 (TA)、可溶性固形物含量 (SSC)、红色皮肤颜色、淀粉糖转化率和内核乙烯浓度。在 3.5°C 下冷藏 3-3.5 个月后，取出样品并评估水果瘀伤、皮肤油腻、腐烂和生理障碍。果皮叶绿素含量与表皮 IAD 测量值呈强正相关。IAD 值在果实成熟期间显着下降，与收获周呈负相关。通过将“收获时”IAD、果实质量和“贮藏后”紊乱数据与相应的收获周对齐来确定最佳收获期。与具有高商业水果质量的收获相关的 IAD 平均值划定了最佳收获边界。由于 IAD 值在果实成熟期间下降，因此将 0.26 的上限值定义为“何时开始收获”，而将 0.12 的下限值定义为“何时结束收获”以进行长期储存。通过将“收获时”IAD、果实质量和“贮藏后”紊乱数据与相应的收获周对齐来确定最佳收获期。与具有高商业水果质量的收获相关的 IAD 平均值划定了最佳收获边界。由于 IAD 值在果实成熟期间下降，因此将 0.26 的上限值定义为“何时开始收获”，而将 0.12 的下限值定义为“何时结束收获”以进行长期储存。通过将“收获时”IAD、果实质量和“贮藏后”紊乱数据与相应的收获周对齐来确定最佳收获期。与具有高商业水果质量的收获相关的 IAD 平均值划定了最佳收获边界。由于 IAD 值在果实成熟期间下降，因此将 0.26 的上限值定义为“何时开始收获”，而将 0.12 的下限值定义为“何时结束收获”以进行长期储存。