MULTIVARIATE ANALYSIS OF THE EFFECT OF DIFFERENT WINE GRAPE POMACE DRYING PROCESSES ON BIOACTIVE COMPOUNDS AND PHYSICAL AND CHEMICAL PROPERTIES

Abstract

Grape by-products are potential functional ingredients in the food industries. Hot air drying is a worldwide technique used to improve food stability, but assessing the effect of high temperatures on the physicochemical and bioactive characteristics of foods is a big challenge since they are complex matrices, and changes can occur through a network of reactions. Thus, this study aims to evaluate the effect of drying grape pomace in an oven, at temperatures of 60 °C, 70 °C and 80 ºC; in a lyophilizer on bioactive compounds (polyphenols and compounds with antioxidant activity); the physical-chemical properties (color, the absorption capacity of water, oil absorption capacity and pH), using principal component analysis (PCA) and cluster analysis (Cluster). The data analysis showed that the lyophilized grape pomace had different characteristics from the kiln-dried samples. Among the dry samples in the range of 60 °C, 70 °C and 80 ºC, the powders obtained showed similar characteristics, representing a single group. Thus, through the PCA and the cluster, it was possible to compare the effect of drying processes on the aspects of the wine grape pomace while simultaneously analyzing a complex set of system characteristics.