Microencapsulation of Vitis vinifera grape pulp phenolic extract using maltodextrin and its application in gummy candy enrichment.

Abstract

Phenolic extract of Vitis vinifera grape pulp was prepared using ultrasonication at frequencies of 28, 40, and 28-40 kHz with a 1:10, 1:15, and 1:20 ratio of solid (grape pulp) to water. The 1:10 ratio and 40 kHz frequency were considered optimal conditions for the preparation of red grape pulp extract (RGPE). Then, RGPE was encapsulated within maltodextrin using a spray drying technique, and the produced powder was used in the gummy candy production. The results revealed that the phenolic content of the powder was almost constant during the storage time. The solubility of the powder decreased, whereas its moisture content increased during the 45-day storage period. The results of scanning electron microscopy showed that the produced microparticles had spherical shapes with a micron size. Fourier-transform infrared spectroscopy and X-ray diffraction showed that RGPE was encapsulated in the structure of maltodextrin through the formation of hydrogen bonds, considering the amorphous structure of the powder. The antioxidant properties of the microencapsulated RGPE containing gummy candy were preserved. Sensory evaluation and colorimetric values of the enriched gummy candy had acceptable results compared to the control sample. In general, microencapsulation of RGPE within maltodextrin as a carrier using the spray drying technique and its application in gummy candy enrichment could be useful.