RESUMO
Avocado fruit is a rich source of phytonutrients such as vitamins, minerals, carotenoids, carbohydrates, polyphenols and unsaturated fatty acids. However, due to its climacteric nature, fruits are highly susceptible to storage temperature, resulting in poor shelf life and reduced quality. In the present study avocado fruits (Accession CHES-HA-I/I) were stored at different low temperatures (5, 9 and 12 °C with 90-95% relative humidity, RH) to identify optimum low temperature for cold storage. In a further experiment, avocado fruits were treated with 1-methylcyclopropene (1-MCP, 500 ppb) and chitosan (0.5%) to extend the shelf life with better fruit quality. The results showed that storage temperatures had significant effect on physiological, biochemical and antioxidant activities of fruits. Lower physiological loss in weight (PLW), reduced respiration and ethylene production, and higher carbohydrates, protein and fat content were recorded in fruits stored at 9 °C as compared to 12 °C. Similarly, maximum antioxidant properties in terms of free radical scavenging activity (FRSA) and ferric reducing ability of plasma (FRAP) was found in avocado fruits stored at 9 °C. It was also noticed that chilling injury was developed in fruits stored under 5 °C. In addition, exogenous application of 1-MCP significantly reduced respiration and ethylene production rate at 9 °C and extended the shelf life up to 42 days with better fruit quality and more antioxidant activities. However, chitosan treated and control fruits had shelf life up to 28 and 21 days respectively, with minimum nutritional content. From this study it is concluded that a storage temperature of 9 °C and 1-MCP treatment significantly enhanced the shelf life of avocado fruits with better fruit quality as compared to other storage temperatures (5 and 12 °C) and postharvest treatment (chitosan).
RESUMO
Capsicums lose water very rapidly after harvest and the moisture loss causes severe shriveling making them unmarketable within 2-3 days. The moisture loss occurs even under low temperature conditions, though at lesser rates. Bell peppers packed in corrugated fiber board boxes (CFB) tend to lose moisture continuously as these boxes are permeable to both water vapour and respiratory gases even if they are non-ventilated. To reduce the moisture loss and maintain freshness, yellow colour capsicum (cv. Bachata) were packed in CFB boxes and over wrapped with different semi-permeable films using shrink wrapping technology. This box shrink wrapping significantly lowered the weight loss and maintained firmness of capsicum at ambient (25.7-33.2 °C and 25-63% RH) and low temperature (8 °C ± 0.5 and 80 ± 5% RH) conditions. Yellow colour capsicums packed in this way could be stored for 11 days at ambient temperature with a weight loss of < 6% as compared to about 20% weight loss in non-wrapped fruits. The storage life could be extended to 5 weeks by storing these shrink wrapped boxes at 8 °C without any shriveling and with a weight loss of < 5%. In addition to maintaining high humidity, the lower O2 and higher CO2 levels maintained surrounding the produce in the wrapped boxes helped to avoid shriveling and to retain the quality in terms of surface colour, firmness and other quality traits. The absorption of excessive relative humidity by CFB itself in the over wrapped boxes helped in avoiding condensation of water droplets. This in turn avoided the development of fungal growth and thus the risk of fruit decay.