PROCESS OPTIMIZATION AND STUDY ON STORAGE STABILITY OF DRAGON FRUIT [Hylocereus Undatus] AND PINEAPPLE [Ananas Comosus] MIXED JELLY

Abstract

The main aim of the work was to optimise the process of dragon fruit and pineapple mixed jelly and study its storage stability at two different temperatures; room and refrigeration. Dragon fruit and pineapple were brought from the local market of Dharan and juice was obtained by the following process. The juices were analysed for TSS, pH, titratable acidity and juice yield. Dragon fruit and pineapple jelly was prepared with the extraction of their respective juices. Firstly, dragon fruit and pineapple were selected, washed, peeled off, and cut. Pineapple slices were grinded for juice extraction and filtered through muslin cloth whereas dragon fruit slices were cooked with equal amounts of water until soft and juice was extracted with muslin cloth. For optimization of dragon fruit juice and pineapple juice, seven sample were prepared as A (50:50), B (62.5:37.5), C (66.67:12.5), D (75:25), E (83.33:16.67), F (87.5:12.5), and Control (100:0) and jelly was prepared maintaining 68 ºBx TSS, 0.8% acidity and 1% pectin content. Sensory attributes of the jelly were evaluated using a nine point Hedonic scale rating test to identify the best product. The sample F was best and used for further analysis in two different temperatures, room (27±3°C) and refrigeration (7±1°C). The jelly was filled in pre-sterilized glass bottles, capped and covered with aluminium foil and stored in two temperatures as room and refrigeration for the period of 45 days and analysed in an interval of 15 days for chemical and microbiological changes. From statistical analysis, it was found that the storage period had significant effect (p< 0.05) in change in reducing sugar, non-reducing sugar, total sugar and vitamin C and no significant effect in TSS, titratable acidity, pH and moisture content of dragon fruit and pineapple jelly. The production cost was found to be NRs. 493.68 per 500 g bottle