Ohmic heating extraction and characterization of rambutan (Nephelium lappaceum L.) peel extract with enhanced antioxidant and antifungal activity as a bioactive and functional ingredient in white bread preparation

Abstract

This study employed the principles of electrothermal process using ohmic heating (OH) to extract phenolic compounds from rambutan peel. Deionized water and ethanol at different concentrations (50% and 70%) were used as electrical-transmission medium at different holding times (15, 30 and 60 min). The result showed significant difference (p ≤ 0.05) between the water and ethanol-based extracts in terms of yield, total phenolic, flavonoid contents and antioxidant activities. The main compounds such as gallic acid, corilagin, geraniin and ellagic acid were identified in the peel. Bread fortified with the extract showed better phenolic content and antioxidant activities, with 15 µg/mL fortification level having excellent texture properties. Interestingly, fortified breads showed excellent antifungal activity, thereby extended the shelf life of the bread crumb. The efficient ohmic heating extraction technique and proper formulation of rambutan peel extract in food, could serves as vital approach for high-quality products development with longer shelf life.