Reducing chilling injury in tomato: bridging the gap between cultivation and postharvest storage

Abstract

Temperature is the most important factor in extending shelf life and maintaining quality in horticultural products (Paul, 1999). Low-temperature storage has been considered to be the most effective method for maintaining the quality of many fruits and vegetables due to its effect on slowing down respiration, ethylene production, ripening, senescence, volatile alteration, and decay. In cold environment the physiological process in plants could be substantially retarded or even completely inhibited . Temperature has a profound effect on the rates of biological reaction (e.g. metabolism and respiration) because enzymes which take part in this process are extremely temperature dependent (Nunes and Emond, 2003). It has also been proved that the growth and proliferation of microorganisms which cause rotting are limited at temperature around 0°C. Moreover, at the same relative humidity, weight loss resulting from moisture loss is reduced at low temperatures. However, instead of getting benefit from low temperature storage, some fruit and vegetable experience detrimental effects known as chilling injury (CI). CI manifests as pitting, uneven and delay of colouring, development of brown areas in the peel, grainy and brown regions in tissues in the outer pericarp, and pathogen proliferation (Maa et al., 2014). CI is a disorder caused by prolonged storage at low temperature and occurs mostly in tropical and sub-tropical fruit and vegetables . Fruit such as mango, banana, papaya, guava, pineapple and tomato are chilling sensitive (Kader, 1999). Numerous intrinsic (e.g., cultivar, preharvest conditions) and extrinsic (e.g., temperature, exposure time to chilling temperatures, air humidity) factors influence severity of CI . CI induced disorders reduces quality and consumer acceptability especially for fruit and vegetables grown in tropical and sub-tropical regions as well as hamper the possibility for transportation to an extended export destination. CI leads to substantial economic losses in the horticultural chain, especially to fruit and vegetables from tropical and sub-tropical origin . The FAO stated fruit and vegetable losses in South-and Southeast Asia can reach up to 51% with more than 35% of those losses during the postharvest and distribution stages of the supply chain (FAO, 2011).Tomato (Solanum lycopersicum) is among the most produced and consumed crops in the world (FAO, 2014). However, post-harvest losses of tomato fruit can reach about 25-42% globally which represents not only quantitative but also qualitative losses (consumer acceptability and fruit nutritional content) (Arah et al., 2015). Tomato fruit quality is dependent on cultivar growing conditions and postharvest handling. The post-harvest life of tomatoes is limited by colour and firmness, and these two attributes determine the acceptance period of fresh tomatoes . In Southeast Asian countries, tomatoes are usually harvested immature, at the mature green or breaker stage which allows storage and transport over longer distance (Chomchalow et al., 2002)...