Physio-chemical Characteristic of Red Dragon Fruit and Pineapple Jam

Abstract

Red dragon fruit is one of fruit that easy to find in Indonesia. The availability of red dragon fruit is quite abundant, especially in harvest season. Sometimes, it became a problem when the fruit didn't sell out and causing some change of quality. One way to extend the shelf life of red dragon fruit is by making jam. Jam is a gel-shape and semi solid food. The making of red dragon fruit jam was combined with the addition of pineapple that contain pectin which help the formation of gels. Sugar was added as sweetener and also as preservatives. On the other side, sugar have a role in gel formation with pectin. Commercial pectin was added to support gel formation in making jam. The factors observed in this study were concentrations of sugar (50,60,70%) and commercial pectin (0, 0.3, 0.5%) that might influence some quality parameters of jam such as spread ability, total soluble solid (TSS), pH, vitamin C and antioxidants value. The best characteristic of jam with spread ability 13.5, 70.5% of TSS value, pH was 4.39, vitamin C value was 0.81% and antioxidants value 19145.91 ppm was obtained with the addition of 50% sugar without the addition of pectin.