Measurement of functional properties and health promoting aspects-glucose retardation index of peel, pulp and peel fiber from Citrus hystrix and Citrus maxima

The objective of this study was to evaluate some functional properties of peel, pulp and peel fiber from Citrus hystrix and Citrus maxima (red and white var), in order to use them as potential dietary fiber sources in the enrichment of foods. These components were analyzed for their functional properties and in vitro health promoting properties. Water holding capacity, oil holding capacity, emulsion activity and emulsion stability of C. hystrix and C. maxima (red and white var) samples were found in the range between 5.18–8.08 mL water/g sample, 1.26–2.45 mL oil/g sample, 29.06–40.68% and 72.12–96.30%, respectively. Glucose retardation index of samples were in the range of 10.43–16.31%, at 180 min. In starch digestion process, all the citrus sample powders showed greater reduction of glucose in dialysate at 20–180 min. Photomicrographs on surface morphology of peel and peel fiber were made by Scanning Electron Microscope (SEM), FTIR spectrum was also recorded for functional group analysis.