ABSTRACT
Twelve low-calorie orange-based formulated jams were prepared mainly from orange, pumpkin and papaya, and then sweetened using fructose (F), stevioside (St) and sucralose (Su). The nutritional value of formulated jams was estimated after the approximate chemical composition and total soluble solid have been determined. The effect of storage on total phenolic compounds, antioxidant capacity, carotenoids content and vitamin C was investigated. Organoleptical attributes of prepared low-calorie jams were done as well. Results indicated that the nutritive value [kcal 100 g–1 fw] ranged from 88.10 ± 0.60 to 164.34 ± 0.41; total phenol content (TPC, mg GAE 100 g–1 fw] ranged from 188.52 ± 2.45 to 411.79 ± 3.3; the antioxidant capacity (μmol TE g–1 fw) ranged from 14.57 ± 0.86 to 32.39 ± 1.19; total carotenoids [mg 100 g–1 fw] ranged from 115.20 ± 5.66 to 204.33 ± 4.21; vitamin C [mg 100 g fw] ranged from 8.94 ± 1.07 to 28.77 ± 4.46; total soluble solids [Brix] ranged from 22.53 ± 0.05 to 43.37 ± 0.13. Jams storage for a period of 12 months at room temperature led to a decrease in vitamin C content, TPC, antioxidant capacity, while total soluble solids (TSS) and carotenoids increased during storage. The results of organoleptical attributes showed that the formulas O11, O1 had the highest score of color and odor respectively while O7 recorded maximum score for taste, texture and bitterness respectively. Statistical analysis showed that storage intervals and treatments had a significant (p < 0.05) effect on sensory quality of diet jam. The organoleptical characteristics were affected with the extension of shelf-life. Addition of stevioside and sucralose to formulate the low-calorie jam increased total phenol and antioxidant capacity, improved color, taste and produced targeted low-calorie jams. The use of sweeteners such as fructose, sucralose and stevioside in the manufacture of orange diet jam was shown to be satisfactory, resulting in low-calorie jams, improved the quality and could be produced commercially.