INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY ISSN Print: 1560–8530; ISSN Online: 1814–9596 11–656/SBC/2012/14–3–389–394 http://www.fspublishers.org Full Length Article To cite this paper: Khan, A.S., N. Ahmad, A.U. Malik and M. Amjad, 2012. Cold storage influences the postharvest pericarp browning and quality of litchi. Int. J. Agric. Biol., 14: 389–394 Cold Storage Influences the Postharvest Pericarp Browning and Quality of Litchi AHMAD SATTAR KHAN 1 , NAVEED AHMAD†, AMAN ULLAH MALIK AND MUHAMMAD AMJAD Institute of Horticultural Sciences, University of Agriculture Faisalabad, 38040, Pakistan †Honest Rice Mills and Foods, Sheikhpura Road, Muridke, Pakistan 1 Corresponding author’s e-mail: ahmad_khan157@yahoo.com ABSTRACT Occurrence of postharvest pericarp browning and rapid decay limit the postharvest storage life of litchi fruit. Effect of low temperature storage on the physico-chemical characteristics of two commercial litchi cultivars ‘Bedana’ and ‘Serai’ stored at 5°C for 0, 7, 14, 21 and 28 days were investigated. Incidence of pericarp browning, disease severity and fruit physico- chemical characteristics were determined immediately after each removal. During cold storage fruit firmness (15‒5.1 N), weight loss (7.06‒1.92%), aril: stone ratio (15.3‒11.7) and sensory values of fruit decreased, whereas fruit pericarp browning index (0.33‒3.25), postharvest disease index (0.5‒2.4) and fruit cracking (0.08‒1.16%) increased. Fruit weight loss, pericarp browning and disease severity were higher in ‘Serai’ than ‘Bedana’ fruit. The fruit of cv. ‘Bedana’ showed better aril: stone ratio (23.07), firmness (2.1 N), pH (4.15), SSC (19.04%), TA (0.14%), total sugars (12.11%) and ascorbic acid (44.8 mg 100 g -1 ) contents than ‘Serai’. Fruit flavour, texture and aroma changed rapidly during cold storage in ‘Serai’ than ‘Bedana’. The pH of fruit juice showed slightly increasing trend during the whole span of storage, while SSC (20.4‒17.4%), TA (0.23‒0.05%), ascorbic acid (55‒32.8 mg 100g -1 ), total sugars (13.5‒10.5%) and phenolics (0.71‒0.45 µg 100 g -1 ) showed decreasing trend. Litchi cv. ‘Bedana’ exhibited higher total phenolic contents (0.71 µg 100 g -1 ) than ‘Serai’ (0.55 µg 100 g -1 ). The fruit of cv. ‘Bedana’ were found superior having less weight loss, pericarp browning index and disease severity index, with higher aril: stone ratio, flavour, texture, aroma, pH, SSC, TA, ascorbic acid, total sugars and phenolic contents. Results suggest that postharvest pericarp browning and fruit quality deterioration can be delayed by cold storage. © 2012 Friends Science Publishers Key Words: Ascorbic acid; Fruit quality; Litchi; Low temperature; Phenolics; Storage period INTRODUCTION The fruit industry of Pakistan is dominated by major fruits such as citrus, mango, banana and date; however litchi is an emerging subtropical fruit crop in Pakistan. It is grown successfully in Punjab (Lahore, Sharaq Pur, Shaikhupura, Sialkot, Taxilla, Cheecha Watni, Multan, Rahim Yar Khan & Kala Bagh), Khayber Pakhton Khaw (Haripur, Hazara, & Khan Pur) and Sindh (Nawab Shah, Moro, Mir Pur Khas, Tando Allah Yar & Hyderabad) (Rajwana et al., 2010). Litchi fruit is preferred for its characteristic sweet- acidic taste, excellent aroma, high nutritive value, succulent aril and bright red colour of its peel. Litchi is a rich source of vitamin C, contains fair amount of phosphorus, calcium, iron, vitamins A and B (Anonymous, 2011). Litchi is an attractive, non-climacteric, highly perishable and environmentally most sensitive tropical to subtropical fruit crop. The fruit has a rough indehiscent pericarp surrounding the succulent, edible aril and a seed in the centre. Skin colour varies somewhat between cultivars, from the light orange-pink to the deep dull-red and purple-red (Sivakumar et al., 2010). Due to cultivar differences litchi fruit may vary widely in texture, size and shape, but one characteristic, which remains constantly desirable is fresh red skin. Pericarp of the fruit lose its bright red peel color, which turns brown within 24 to 28 h after harvest (Zheng & Tian, 2006). Pericarp browning reduces its commercial value and has been considered the main postharvest problem worldwide (Kumar et al., 2011). The incidence of postharvest pericarp browning in litchi fruit is regulated by various factors such as activity of polyphenol oxidase (PPO) enzyme (Zauberman et al., 1991), desiccation (Scott et al., 1982), changes in endogenous anthocyanins contents (Underhill & Critchley, 1994), storage conditions (Sivakumar & Korsten, 2006), storage temperature (Jiang et al., 2003b), postharvest fruit coatings (Joas et al., 2005), hot water treatments (Olesen et al., 2004), postharvest application of polymaines, antioxidants (Kumar et al., 2011), ascorbic acid (Sun et al., 2010), oxalic acid (Zheng & Tian, 2006) and cultivars (Sivakumar et al., 2010). However, among these factors, rapid moisture loss, degradation of anthocyanin by PPO and peroxidase