Study on Processing and Quality Evaluation of Low Sugar Purslane and Purple Sweet Potato Jam

In order to meet the needs of consumers for diversified taste and healthy diets, a scientific formula and advanced manufacturing method for a new type of jam with low-sugar and no preservative were developed. By using purslane and purple sweet potato, which are rich in functional factors for human health, as the main raw materials, the formula of purslane and purple sweet potato jam was optimized through single factor experiment and orthogonal test, and the nutritional, physicochemical and sanitary indexes of the final product just produced and stored for a period of time were determined. The results showed that the optimal formula for low-sugar purslane and purple sweet potato jam were as follows: Purslane stem juice and purple sweet potato pulp mass ratio was 5:5, amount of citric acid added was 0.3%, amount of xylitol added was 25%, and amount of thickener addition was 0.4%. Based on this optimized formula, the purslane and purple sweet potato jam produced had purplish-red color, uniform texture, delicate taste, moderate acidity and sweetness, unique aroma of purslane and purple sweet potato, and sensory score of 90.5±0.4 points. The final product had 42.32±1.43% soluble solid content, 13.41±0.52 g/100 g total sugar content, and pH3.61±0.18, 0.83±0.08 g/100 g crude protein content, 3.77±0.11 mg/100 g V_C content, 4.18±0.10 mg/g flavonoids content, 2.05±0.13 mg/g polyphenols content and 37.27±0.84 mg/100 g anthocyanins content, and all the above physicochemical and sanitary indexes met the national standards for jams. The IC₅₀ value of the purslane and purple sweet potato jam on DPPH free radical was 7.071 mg/mL, indicating that it had certain antioxidant activity. After being stored at 25 ℃ and 37 ℃ for 1 month respectively, the sensory score and various nutritional components of the jam decreased to some extent with the total number of bacteria increased, but they still met the national standards for jams. The results of this study could provide reference for the deep processing of purslane and purple sweet potato and the standardized production of purslane-purple sweet potato jam.