Physio-biochemical,Quality And Microbial Characteristics:An Analysis Of Watermelon Cultivars For The Fresh-cut Industry

The tremendous health benefits of watermelon,coupled with increasing consumer demand for healthier and convenient foods have been catalyzing the fresh-cut industry.However the nature of fresh-cut processing,while providing the advantages of convenience and cleanliness to consumers,increases susceptibility to spoilage thus limiting storage life.As the world's largest watermelon producer,many of China's watermelon cultivars have remain relatively unexplored in relation to their suitability for the fresh-cut market.This study therefore investigated the changes in quality,physio-biochemical and microbial characteristics of fresh-cut watermelon of 10 widely grown cultivars in China,available in summer(Qilin,Heimeiren,Texiaofeng,8424 seeded and JingXin#1)and autumn(Luye,Heimawangzi,Zaokangjingxin,Sumiwuzi#1 and T1518)stored for 5 days at 5?.The results indicate that high respiration rates and the presence of seed cavities resulted in high juice leakage and weight loss for Jingxinll and 8424 seeded,which also had significant color change after 5 days of storage.Aerobic bacterial count and Total coliform bacteria for all cultivars increased as storage time extended,to less than 5.0Log10 CFU/g and 4.0 Log10MPN/100g respectively with no visible symptoms of decay.The slight changes in quality characteristics(color,firmness,Total Soluble Solids Content(TSS),pH,juice leakage,weight loss)of fresh-cut Qilin,Heimeiren and Texiaofeng cultivars during storage,suggest that these summer cultivars are better suited for fresh-cut.In comparison to summer cultivars,fresh-cut autumn cultivars were characterized by lower respiration rates,aerobic bacterial count,total coliform bacteria,%juice leakage and%weight loss.Higher juice leakage and%weight loss of fresh-cut Zaokangjingxin and Luye cultivars,led to increased softening(firmness loss)and slight color change which was evident upon visual appraisal by water soaked spots.Aerobic bacterial count and Total coliform bacteria increased synchronously with storage to less than 4.0 Log10CFU/g and 4.0 LogioMPN/100g respectively.Minimal changes in quality and respiration rate of fresh-cut Heimawangzi,Sumiwuzi#1 and T1518 suggest that these cultivars are better suited to fresh-cut processing.Microbial quality,respiration rate,juice leakage and weight loss were found to be the key indices for determining the suitability of watermelon cultivars for fresh-cut purposes.