Influence of Natural Extracts Dipping to Maintenance Fruit Quality and Shelf Life of Egyptian Guava

Abstract

Guava fruits are considered sensitive to low temperature and susceptible to infection by decay causing fungi making its transport and storability difficult. Use of plant extracts which having fungicidal and insecticidal properties is one of the alternative methods against fungi causing guava decline disease caused by Phomopsis psidii, Lasiodiplodia theobroma and Epicoccum spp. Therefore, the present investigations were conducted during 2016 and 2017 seasons on guava fruits cv. Bassateen El Sabahia for maintaining quality and control disease development under cold and ambient conditions. The guava fruits were harvested at physiological maturity stage during the third week of January and treated with marigold flower extract, neem extract and mentha leaf extract at (10%) as dip treatment for 5 minutes. (Experiment 1).Treated fruits were packed in ventilated Corrugated Fibre Board (CFB) boxes and stored 28 days under cold storage at 6° C ± 2° and humidity 90-95% R.H. (Experiment 2). The fruits were stored for 6 days in ambient conditions at 15° C ± 2° with 65 – 70 % R.H. Under both of the storage conditions, all treatments exhibit potential to maintain the postharvest life of fruits by reducing linear growth and dry weight of the fungal spoilage as compared with untreated fruits. The lowest significant values of disease infection percentage were recorded by dipping fruits in neem leaf extract at 10% after 28 days of cold storage and 6 days at marketing in the two seasons. Among all extracts, neem in combination with (CFB) boxes effective in registered higher potential to retain the fruit quality for longer period under both conditions by reducing the weight loss, fruit spoilage and retaining the fruit firmness and quality attributes such as TSS, sugars, vitamin C and pectin. On the other hand, 10% Mentha leaf extract followed by marigold flower extract treatments proved to be highly effective in reducing spoilage under these treatments with respect to the untreated ones. Generally, the promising effects of these treatments showed that the winter season guava fruits can be stored up to 28th day under cold storage and up to 6th day under ambient condition without deteriorating the fruit quality.