Quality of Clementine Jam Influenced by Purée Pretreatment, Sugar Type and Pectin Addition

摘要

The aim of this research was to investigate the influence of several parameters on quality of Clementine (Citrus clementine) jam. Thermal treated and nontreated Clementine purée, two types of sugar (sucrose and fructose) and three different amounts of added pectin were used for the jam producing. Accordingly, twelve jams were prepared and sorted in four groups, two of nontreated purées and two of treated purées, and each one with sucrose and fructose within. The quality of jams was evaluated through gel strength measurement, sensory evaluation and level of polyphenols. The results of gel strength measurement showed that the treated purée jams were less firm than nontreated ones, the jams with sucrose were firmer than the ones with fructose and the gel strength of jams increased with amount of added pectin increase. Jams of nontreated purée contained higher level of polyphenols in comparison with jams of treated purée. Regarding to sensory evaluation, the nontreated purée jams were higher rated in comparison to treated ones. Furthermore, jams with fructose were better evaluated than jams with sucrose. Based on obtained results, it is revealing that nontreated purée jam with fructose and 0.7 % added pectin was the best sensory evaluated sample.