Influence of steam cooking on pro-health properties of Small and Large variety of Momordica charantia

Steam cooking is one of the most common preparations of Momordica charantia dishes. This method improved the tastiness of the fruits but at the same time, some changes occurred in the volatile and non-volatile parts of their food matrices. In this study, for the first time these properties were correlated with the found substances affecting the bioactivity of this fruit. Two varieties of Momordica charantia were analysed and compared. It was possible to differentiate both types of fruits using two-dimensional gas chromatography and time-of-flight mass spectrometry (GC×GC-TOF-MS) as well as to assess botanical and geographical origin. In the case of volatiles, 212 chemical compounds were tentatively identified, which can be classified into seven chemical classes, such as aldehydes, alcohols, esters, ketones, terpenes, hydrocarbons. Furthermore, 16 of them were quantified and calculated in terms of OAV and ROC values. Bioactive substances (polyphenols, flavonoids, tannins and flavanols) and the values of antioxidant capacities by four radical scavenging assays (DPPH, CUPRAC FRAP, ABTS) were determined and compared in water and methanol extracts of Chinese and Indian varieties. It was proven that steam cooked Chinese variety has greater value due to its flavour than Indian variety and consists more volatile, non-volatile and bioactive constituents with high antioxidant effect. The binding properties of polyphenols to HSA were relatively high in comparison with other plants. A strong positive correlation of binding properties and bioactivity of Momordica charantia was estimated. One of the volatiles, namely citronellol, has key importance in respect of antidiabetic effect of Momordica charantia Chinese variety. This study indicates pro-health preponderance of Chinese variety over Indian variety and confirms that steam cooking is in lines with the canons of safe food preparation.