Metabolomics approach to study factors affecting quality and postharvest stability of Kinnow Mandarin

Abstract

Kinnow (Citrus nobilis x Citrus deliciosa) is an important mandarin revolutionizing the citrus industry. Nutrition, flavor and processing quality of Kinnow are governed by various primary and secondary metabolites. Targeted and untargeted metabolomics tools have been deployed to understand the fruit juice metabolome of a commercially newlineimportant Kinnow mandarin. A suite of chromatography and massspectrometry newlineplatforms complemented with data analytics and visualisation provided insights into the identities and quantities of a range of metabolites responsible for flavour, nutrition and processing attributes of Kinnow juice. Results show that Kinnows from subtropical arid climatic conditions with higher levels of sugars, vitamins, lower levels of limonoids, alcohols, aldehydes and moderate levels of polyphenolics have high quality and are more suitable for fresh and processing industry. newlineCleopatra mandarin and Rough lemon 1 rootstocks providing optimum sugars, acids, phenolics, vitamins in conjunction with low limonin and naringin concentrations are better for grafting quality Kinnow. Harvest newlinematurity in Kinnow is marked by increase in sugars, vitamin B complex,volatiles and decline in polyphenolics and limonin. Asymptomatic Kinnows from trees infested with Asian citrus psyllid and infected with newlinePhytophthora spp. accumulated higher polyphenolics, limonoids and volatiles. Kinnow harvested at commercial maturity may be safely stored for 35 days at low temperature and 14 days at room temperature. Storage beyond this duration led to accumulation of limonin and off flavour newlinevolatiles and fruit quality deterioration. Coated Kinnows maintained their quality with long-term storage at low temperature as compared to uncoated Kinnows. Carnauba based coatings are better suited for coating Kinnows as compared to shellac based coatings due to accumulation of off flavor volatiles and altered flavor profile in the later, rendering them unsuitable for long term storage of Kinnow. newline