Colour retention of litchi (Litchi chinensis Sonn.) after harvest - a review

The perishability of litchi fruit limits marketing, especially exports to countries with some distance from main areas of production. The major postharvest problem is pericarp browning that is associated with rapid pericarp desiccation, anthocyanins degradation and disease. Low temperature (1-5°C) storage can reduce physiological decay, but it has only a limited role in reducing pericarp browning. Sulphur is often used to reduce both decay and browning, with postharvest fungicides also providing good control of disease. However, there is increasing pressure from consumers to find alternatives to chemicals while still satisfying the demand for sound, blemish-free fruit of good quality. A combination of low temperature (2-5°C), high humid conditions and polyethylene packaging are reported to be effective for control of browning. Other available options include use of VapourGuard and treatment with organic acids, edible coatings, potassium metabisulphite, methyl jasmonate and chlorine dioxide. All these treatments have been reported to reduce postharvest decay and peel browning. This paper reviews the available technology for colour retention of litchi after harvest.