Study on Formulation, Quality Evaluation and Storage Stability of Agar Based Dragon Fruit Jelly Incorporated with Stinging Nettle

Abstract

The main aim of this study was to optimize the preparation of jelly made from dragon fruit juice and stinging nettle extract and to evaluate its storage stability at room temperature and refrigeration temperature. Dragon fruit and stinging nettle were purchased from the local market in Dharan, and juice was obtained through the following process. Fully ripened dragon fruits were washed, peeled, and sliced. The flesh was then cooked with water until it softened and then strained through muslin cloth to extract the juice, whereas Fresh nettle leaves were washed, blanched at 90 °C, dried at 50 °C to constant weight, ground into powder, extracted with hot distilled water for 30 min, and filtered through Whatman No. 1 to obtain the nettle extract. Seven different samples of different proportion of dragon fruit juice and stinging nettle extract were taken and coded as A (67: 33), B (63:37), C (75: 25), D (100:0) which is control, E (83:17), F (50: 50) and G (88: 12). The sugar, citric acid and Agar agar was added in the amount of 130g, 0.5% and 2% respectively. Sensory attributes of the jelly were evaluated using a nine-point Hedonic scale rating test to identify the best product. Sample C was the best and was used for further analysis at two different temperatures: room temperature (27±3°C) and refrigeration (7±1°C). The effect of storage time on physicochemical and microbial properties was evaluated. The jelly was filled in pre-sterilized glass bottles, capped, and covered with aluminium foil and stored at two temperatures as room and refrigeration, for a period of 40 days, and analysed at intervals of 10 days for chemical and microbiological changes. Physicochemical analysis of the optimized product revealed TSS of 67°Bx, pH of 3.1, acidity of 0.56% and notable antioxidant activity 73.48%. During 40 days of storage, TSS, acidity, reducing sugar,

and microbial counts gradually increased, whereas vitamin C, pH, moisture, and non- reducing sugars decreased. Even with these changes, the jelly remained microbiologically

safe and acceptable without using chemical preservatives. The incorporation of stinging nettle enhanced the phytochemical profile of the jelly, offering a novel, shelf-stable confectionery product with improved nutritional and functional properties. This research also shows how underutilized crops can be turned into valuable food products, while supporting the growing consumer interest in natural and health-promoting foods.