Effect of juice extraction and concentration methods on quality of rambutan syrup and its application as sweetener in food products

Abstract

The objectives of this research were (1) to study the effect of the extraction methods and juice concentration process on the quality of rambutan syrup, (2) to study the utilization of rambutan syrup as a sweeteners in food products by analyzing the physical properties and sensory evaluation. The result of juice extraction, it was found that the optimum condition of juice extraction with cellulase enzyme gave highest yield for 79.67 % and 14.18 %RSS. For rambutan syrup production by the open pan and the vacuum evaporation, the open pan evaporation method showed that the highest optimum condition was 16.83 %yield at 70 °C for 2.25 hr. While the yield of vacuum evaporation method was 13.96 % at 70 °C for 1.10 hr. The overall liking score of the syrup prepared from both concentration methods were rate by panelists as liked moderately.

The utilization of rambutan syrup as sweetener in food products, the optimum level of rambutan syrup could be used to replace in pie product was 17.20 %, and 5.70 % of pasteurized flavored – milk product. Which all sensory attributes were accepted at the medium score. For the quality analyzed, the water activity (a_w) of rambutan pie was 0.88 and 27.23 % moisture. The pasteurized flavored – milk had 24.13 %TSS, 5.99 of pH, and the color values (L* a* b*) were 54.43, - 0.63 and 8.36, respectively. The products could be kept at 5 °C for 14 days, total microorganism was found < 300 CFU/ml.