Ethanol vapor treatment of ‘Laetitia’ plums stored under modified atmosphere

Abstract The objective of this work was to evaluate the effect of ethanol vapor during storage in modified atmosphere on the ripening and maintenance of the postharvest quality of ‘Laetitia’ plums. The plums were obtained from an orchard in the municipality of Lages, SC. The experimental design adopted was completely randomized. The treatments evaluated were ethanol vapor doses (0, 2, 4, 6 and 8 mL kg-1 of fruit). The fruits were stored at 0.5±0.2°C and 92±2% RH for 30 days. Upon their removal from storage followed by another three days in room conditions (20±5ºC and 63±2% RH), the fruits were evaluated in relation to their physical and chemical attributes, incidence and intensity of internal browning, quantification of ethanol, acetaldehyde and ethyl acetate, and the activity of enzymes peroxidase and superoxide dismutase. The application of ethanol vapor was efficient in maintaining the fruits flesh firmness, reducing the evolution of the red coloring, and resulted in greater activity of enzymes peroxidase and superoxide dismutase. However, the doses evaluated were not efficient in reducing the internal browning.

摘要 本研究旨在评估气调贮藏（modified atmosphere）环境下乙醇蒸汽对‘拉蒂蒂亚’李子（‘Laetitia’ plums）采后成熟进程与品质维持的影响。试验所用‘拉蒂蒂亚’李子采自巴西圣卡塔琳娜州拉热斯市（Lages, SC）的果园。本实验采用完全随机设计，设置的处理为不同剂量的乙醇蒸汽：0、2、4、6及8 mL·kg⁻¹果实。供试果实于0.5±0.2℃、相对湿度（Relative Humidity，RH）92±2%的条件下贮藏30天；取出贮藏果实后，先在室温环境（20±5℃、相对湿度63±2% RH）下放置3天，随后对其理化指标、内部褐变的发生率与严重程度、乙醇、乙醛及乙酸乙酯的含量，以及过氧化物酶（peroxidase）和超氧化物歧化酶（superoxide dismutase）的活性进行测定。结果显示，乙醇蒸汽处理可有效维持果肉硬度、抑制红色着色加深，并显著提升过氧化物酶与超氧化物歧化酶的活性；但本研究所用的各剂量乙醇蒸汽均未能有效降低内部褐变的发生。