Metabolic fate of contaminant residues in grapes at various stages of processing to raisins and wines

Abstract

Grape is an important commercial fruit crop, which receives frequent application of large number of agrochemicals, e.g. pesticides etc. throughout the cropping season for management of various pests and diseases. At present, in India grape is grown over an area of 60,000 ha with an annual production of 1.2 million tonnes. It is estimated that around 1200 hectares area with annual production of 9.5milian liters in Maharashtra and about 100 hectares near Bangalore in Karnataka are currently under wine grape cultivation. Indian grape is under constant scrutiny of the environment and health protection agencies worldwide. In India, the cultivation of grapes receive frequent application of large number of pesticides and further, grape is mostly consumed as fresh fruit in intact form without any processing. The residues left on the grapes during harvest can be carried through into the wine. When grapes are processed to raisin or wine, the contaminant molecules are expected to degrade on exposure to various processing treatments. Raisins are prepared by drying the grapes under sun or shade and oven drying whereas wine is prepared through fermentation. Hence during raisin and wine preparation, the agrochemical residues get exposed to various biotic and abiotic factors and may degrade by photodegradation, chemical degradation and microbial degradation. Thus, processing of grapes may appear to be a major method of decontamination of residues to provide safety to the consumers. Chapter 1 embodied brief introduction to grape and grape products (raisin and wine). It gives the review about pesticides, antibiotics residue analysis from grapes, raisin and wine. Also it explains the review of literature for journey of pesticides during the processing of grape to wine and raisin. Chapter 2 explained the validation and uncertainty analysis of a multiresidue method for pesticides in grapes using ethyl acetate extraction and Liquid chromatography tandem mass spectrometry. A method was validated for the multiresidue analysis of 82 pesticides in grapes at ≤25 ng/g level. Berry samples (10 g) mixed with sodium sulphate (10 g) were extracted with ethyl acetate (10 mL); cleaned by dispersive solid phase extraction and the results were obtained by liquid chromatography–tandem mass spectrometry. Reduction in sample size and proportion of ethyl acetate for extraction did not affect accuracy or precision of analysis when compared to the reported methods and was also statistically similar to the QuEChERS technique.