The use of neem oil and chitosan during pre-harvest and in the post-harvest quality of the ‘Paluma’ guava

ABSTRACT Guava is a fruit that is susceptible to attack by pests and diseases both pre- and post-harvest, making it important to employ techniques which maintain its quality, such as the use of neem-based products and chitosan together with cold storage. The aim of the present study was to evaluate the use of neem oil and chitosan during pre-harvest and in the post-harvest quality of the ‘Paluma’ guava. The experiment was conducted on a property in the district of Mamanguape, Paraíba. Eighteen guava trees were selected, and the following treatments were applied: a control; neem oil 0.5%; neem oil 1%; chitosan 0.5%; chitosan 1%; neem oil 0.5% + chitosan 0.5%; neem oil 0.5% + chitosan 1%; neem oil 1% + chitosan 0.5% and neem oil 1% + chitosan 1%. When at the commercially mature stage, the fruit was harvested, packed in a harvesting crate and transported to the Post-Harvest Physiology Laboratory (CCHSA/UFPB). The fruit was selected, stored at 24 ± 1 °C and evaluated for 10 days, and then stored at 10 ± 1 °C and evaluated for 20 days, followed by physical, chemical and enzymatic analysis. Coating with neem oil (0.5%) + chitosan (1%) during pre-harvest proved to be effective in preserving and prolonging the quality of the ‘Paluma’ guava during storage for 8 days at 24 ± 1 °C, and 16 days at 10 ± 1 °C.

摘要
番石榴（guava）在采前与采后阶段均易遭受病虫草害侵袭，因此采用维持其品质的技术至关重要，例如联用印楝基产品、壳聚糖（chitosan）结合冷藏（cold storage）处理。本研究旨在评估采前施用印楝油（neem oil）与壳聚糖对‘Paluma’番石榴采后品质的影响。试验于巴西帕拉伊巴州马曼瓜佩（Mamanguape）区的一处果园开展，选取18株番石榴树，设置如下处理组：空白对照组；0.5%印楝油组；1%印楝油组；0.5%壳聚糖组；1%壳聚糖组；0.5%印楝油+0.5%壳聚糖组；0.5%印楝油+1%壳聚糖组；1%印楝油+0.5%壳聚糖组；1%印楝油+1%壳聚糖组。当果实达到商业成熟度时进行采收，装入采收箱后转运至采后生理实验室（Post-Harvest Physiology Laboratory，CCHSA/UFPB）。随后对果实进行分选，先置于24±1℃条件下储存并连续10天开展品质评估，再转移至10±1℃条件下储存并连续20天开展品质评估，之后进行物理、化学与酶学分析。试验结果表明，采前采用0.5%印楝油+1%壳聚糖涂膜处理的方案，可有效维持并延长‘Paluma’番石榴在24±1℃下储存8天、10±1℃下储存16天的品质。