Effect of Heat Processing Treatments and Extraction Solvents on the Phenolic Content and Antioxidant Activity of Momordica charantia Fruit

Abstract

The effect of different cooking treatments and extracting solvents on the antioxidant activity of M. charantia was assessed by measuring total phenol content (TPC), total flavonoids, tannin content and carotenoid content and the antioxidant activity using different assays. A densitometric HPTLC analysis was performed for the analysis of phenolic acids and flavonoids. In general, the recovery of TPC and antioxidant activity was highest in methanolic extract. The most of cooking treatments exerted the decreasing effect on antioxidant activity. Correlation studies indicated that the phenols were mainly responsible for ferric reducing power (r = 0.872, P < 0.01). However, the flavonoids were responsible for radical scavenging activity (r = 0.857, P < 0.01). HPTLC analysis of the methanolic extracts revealed the prominent presence of caffeic acid, vanillic acid, quercetin, catechin, etc., in the native form and destruction, transformation and formation of new phenolics was observed after the cooking treatments. Practical Applications In the present study, three cooking treatments such as pressure cooking, microwave cooking and frying were compared in respect to the retention of antioxidant potential of Momordica charantia fruit. The findings of the present study suggested that pressure cooking and frying could be developed as effective heat processing techniques to retain the maximum antioxidant potential of M. charantia fruit. This report can also serve as a database giving information about retention of polyphenolic compounds after cooking which may help in the establishment of recommended daily allowance value of polyphenolic compounds particularly for the population relying heavily on the consumption of M. charantia. Since, the beneficial health effects of consumption of M. charantia are well established in the Indian Ayurveda, this study can be instrumental in adding new scientific dimension in understanding the beneficial health aspects of M. charantia.