A Targeted Metabolomics Approach to Study Secondary Metabolites and Antioxidant Activity in 'Kinnow Mandarin' during Advanced Fruit Maturity.

In this study, we investigated the impact of harvest maturity stages and contrasting growing climates on secondary metabolites in Kinnow mandarin. Fruit samples were harvested at six harvest maturity stages (M1−M6) from two distinct growing locations falling under subtropical−arid (STA) and subtropical−humid (STH) climates. A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) technique was employed to identify and quantify secondary metabolites in the fruit juice. A total of 31 polyphenolics and 4 limonoids, with significant differences (p < 0.05) in their concentration, were determined. With advancing maturity, phenolic acids and antioxidant activity were found to increase, whereas flavonoids and limonoids decreased in concentration. There was a transient increase in the concentration of some polyphenolics such as hesperidin, naringin, narirutin, naringenin, neoeriocitrin, rutin, nobiletin and tangeretin, and limonoid aglycones such as limonin and nomilin at mid-maturity stage (M3) which coincided with prevailing low temperature and frost events at growing locations. A higher concentration of limonin and polyphenolics was observed for fruit grown under STH climates in comparison to those grown under STA climates. The data indicate that fruit metabolism during advanced stages of maturation under distinct climatic conditions is fundamental to the flavor, nutrition and processing quality of Kinnow mandarin. This information can help in understanding the optimum maturity stage and preferable climate to source fruits with maximum functional compounds, less bitterness and high consumer acceptability.

Targeted metabolite profiling to gain chemometric insight into Indian pomegranate cultivars and elite germplasm.

BACKGROUND: Pomegranate fruit is an excellent source of bioactive polyphenolics, known to contribute significantly to human health. India is the largest producer of pomegranate in the world and produces the finest quality fruit with highly desirable consumer traits such as soft seeds, low acidity, and attractive fruit and aril color. Knowledge of the extent of variation in key metabolites (sugars, organic acids, phenolics, and anthocyanins) is key to selecting superior genotypes for germplasm improvement. Relevant information with respect to Indian genotypes is scarce. The present study therefore aims to evaluate quantitatively important metabolites in some cultivars and elite germplasm of pomegranate in India. RESULTS: Identification and quantification of primary and secondary metabolites such as sugars, organic acids, vitamin C, polyphenolics, and anthocyanins were conducted using a liquid chromatography - mass spectrometry (LC-MS) platform. Fructose and citric acid were the predominant sugar and organic acid, respectively. Wild genotypes had significantly higher concentrations of organic acids, antioxidant activity, and phenolics, namely punicalagin, ellagic acid, sinapic, and ferulic acid. CONCLUSION: Cyanidin and delphinidin derivatives of anthocyanins were more abundant in red aril commercial genotypes. Results suggest that wild-sour accessions represent a rich source of polyphenolics that can be utilized in future breeding programs to breed healthier varieties, food supplements, and pharmaceutical products. © 2019 Society of Chemical Industry.

Postharvest vapour heat treatment as a phytosanitary measure influences the aroma volatiles profile of mango fruit.

Our objective was to determine the influence of postharvest vapour heat treatment (VHT) on qualitative and quantitative measurement of aroma volatiles during fruit ripening in mango (cv. Chausa) using gas chromatography-mass spectrometry (GC-MS). VHT (48°C for 20 min) accelerated the process of fruit ripening leading to edible-soft stage within 4 days after heat treatment against 8 days in control. Reversible inhibition of aroma volatiles emission was observed in heat-treated fruit, with a significant alteration in aroma volatiles profiles at different stages of fruit ripening. The heat-induced increase in the rate of fruit ripening proceeded with a significant lag in the emission of aroma volatiles. The suppression of aroma volatiles at ripe stage in heat-treated fruit might adversely impact the consumer acceptance of fruit.