Vol. 2, Issue 6 (2017)
Nutritional evaluation of selected underutilized edible fruit species of Syzygium R.Br. ex Gaertn. from Kerala, India
Author(s): AR Jisha Chand, K Azeez
Abstract: The underutilized, edible fruits of Syzygium cumini (L.) Skeels Syzygium gardneri Thwaites and Syzygium zeylanicum (L.) DC. from Agasthyamala Biosphere Reserve, Kerala were investigated for their nutritional and antioxidant potential. The fruit of Syzygium gardneri Thwaites possessed the highest values of energy (97.35 ± 1.70 kcal 100g-1), total carbohydrate (21.36 ± 0.75%), total protein (2.56 ± 0.40%), crude fiber (1.80 ± 0.05%) and total ash (0.86 ± 0.08%) but the lowest fat (0.19 ± 0.04%) and moisture content (75.04 ± 0.42%). Syzygium cumini (L.) Skeels fruit got the highest fat (0.39 ± 0.02%) and moisture content (86.91 ± 0.90%). Of all the investigated metals, the best represented in all the fruits were sodium, potassium, calcium and magnesium. The rest of the metals strontium, chromium, manganese, copper and zinc were identified in much smaller quantities. Cadmium and cobalt were not detected and lead content was not detected in Syzygium gardneri Thwaites but it was present in the other two species in very low concentrations (0.01 mg 100g-1), under the toxicity limits admitted by law. Syzygium cumini (L.) Skeels fruit contained the highest amount of potassium (590 ± 0.07 mg 100g-1), calcium (250 ± 0.56 mg 100g-1), chromium (0.11 ± 0.01 mg 100g-1), iron (2.42 ± 0.01 mg100g-1), copper (0.15 ± 0.01 mg 100g-1), manganese (1.43 ± 0.02 mg 100g-1) and zinc (0.21 ± 0.01 mg 100g-1) where as Syzygium zeylanicum (L.) DC. fruit was rich in sodium (630 ± 0.06 mg100g-1). Syzygium gardneri Thwaites fruit contained high amount of magnesium (30.51 ± 0.66 mg 100g-1), strontium (0.18 ± 0.01 mg 100g-1) and showed remarkable antioxidant properties with highest total phenolic content (0.88 ± 0.02%), total flavonoid content (0.30 ± 0.01%), ascorbic acid (0.28 ± 0.02%) and the strongest antioxidant activity (85.49 ± 0.04%) at the concentration of 100 μgml-1. There was a significant difference at p < 0.05 between all of the three species in antioxidant activity and the antioxidant potential of the studied fruits was in the following decreasing order: S.gardneri > S. cumini > S.zeylanicum. The composition of bio elements and active antioxidants revealed that these underutilized fruits could be explored as a viable source of natural antioxidants for the functional food and pharmaceutical applications.