Effect of composite thickening agent and color protection agent on the quality of low sugar raspberry jam

Red raspberry was used as raw material, and the seedless treatment method was adopted.Then the xanthan gum and agar were used as a thickening agent, and sodium chloride and vitamin C were used as the color protection agent.The effect of composite thickening agent on texture properties and sensory quality of low sugar raspberry jam was carried out. By response surface experiments, process parameters of low sugar raspberry jam were optimized. Results showed that the proportion of xanthan gum and agar was 7∶ 3 ( composite thickening agent 0.2%) , and the hardness and adhesiveness of jam between storage0 day and 90 days had no difference, which had slow flow, no juice secretion and no compaction.While the proportion of sodium chloride and VCwas 2∶ 3 ( color protection agent 0.8%) , L^*value reached the highest, a^*and b^*values were the the smallest.The colour of jam between storage 0 day and 90 days at 4 ℃ had no difference and its sensory quality was the best.The optimum process parameters of response surface were the addition of composite thickening agent 0.40%, the addition of sugar 47%, the addition of color protecting agent 1.40%.Under the conditions, the color score of the jam was 9.1, its aroma score was 9.5, its texture score was 19.1, its taste score was 18.8 and its quality was wonderful. In conclusion, composite thickening agent and color retention agent are important for the development of low sugar jam.