การผลิตน้ำลิ้นจี่และน้ำมะม่วงอัดก๊าซคาร์บอนไดออกไซด์

Abstract

Carbonated fruit juice is a diversification juice product that has a potential to increase the consumption of fruit juice and elevate the demand of Thai fruit. In this project, lychee and mango juices were carbonated and assessed for their physiochemical, microbial and sensorial properties. Doing pasteurization at 95 °C for 30 s for lychee and mango juices at 18 and 14 °Brix, respectively, significantly produced color changes and vitamin C reduction of both the studied juices (P<0.05) However, the heat treatment did not significantly affect total soluble solid, pH and total acidity of the juices (P>0.05). When lychee and mango juices were carbonated with soda water or dry ice at different addition levels, the carbonation methods affected the overall qualities of carbonated lychee and mango products. The addition of dry ice in the studied juices significantly produced carbonated products with higher physiochemical qualities and better sensorial acceptance compared to those of the juices supplemented with soda water (P<0.05) Higher levels of soda water significantly resulted in lower lightness value (L*), green color intensity (-a* value), total soluble solid, total acidity and vitamin C of the carbonated juices. However, pH and carbon dioxide content of the carbonated juices were significantly increased with higher levels of soda water (P<0.05) On the other hand, addition levels of the dry ice did not significantly affect the physicochemical characteristics of the carbonated lychee and mango juices (P>0.05) It was found out that dry ice at a ratio of 2:1 (w/v) produced carbonated lychee and mango juices with the highest sensory acceptance score. The microbial numbers of carbonated fruit juices were very low. An application of Just about right scale to examine the sensorial acceptance of the carbonated lychee and mango juices revealed that the lychee juice needed to be added with 1.25% (w/w) citric acid to receive a panelist acceptance of ‘slightly like’, while the mango juice received a similar acceptance without any adjustment in the product composition. Carbonated lychee and mango juices were also prepared from concentrated juices and juice purees that were stored for 8 weeks at 4 °C. The physicochemical and sensorial properties of the carbonated juices displayed that the carbonated lychee and mango juices from purees had the qualities that were not significantly different than those prepared from the fresh juices and were significantly higher qualities than those made from concentrated juices (P<0.05) Longer storage times of the puree reduced the total qualities of the carbonated fruit juices. The carbonated lychee and mango juices prepared from dry ice and juice purees at a ratio of 2:1 (w/v) were stored at 4, 30 and 45 °C for 8 weeks. Storage data displayed that the overall quality of the carbonated juices significantly decreased at higher storage temperatures and longer storage times, except for the total soluble solid and volume of carbon dioxide of the juices. No microorganisms were detected during storage of the carbonated juices. Keeping the carbonated products at 4 °C significantly retarded the deterioration of the product qualities compared to those that were stored at 30 and 45 °C (P<0.05)