Nutritional and Antioxidant Properties of Sri Lankan Tropical Almond (Terminalia catappa L.) Nuts

Abstract

Sri Lanka being a country which experiencing a nutrition transition has an urgent need to search new food sources to nourish the people. Therefore, this study aimed to evaluate the nutritional and antioxidant potential of underutilized fruit; tropical almond (Terminalia catappa) (TA) nuts as a novel food source. The nutritional profile was estimated in terms of moisture, protein, fat, ash, carbohydrate content and energy value while the mineral composition was analyzed using Inductively coupled plasma mass spectrometry (ICP-MS). Further bioactive compounds and antioxidant properties of TA nuts were estimated. Interestingly the moisture content of the dried nuts was 7.50±0.95 lower than recommended value of 10% for edible nuts. It showed 21.32± 0.27% of protein which contributed to 38-46% of Dietary Reference Intake (DRI) of protein of an adult. Further, the protein fraction contributed nearly 13% of total energy of the TA nut. More than half (53.76±2.41%) of weight of the nut was fat, contributing 55.42-122.15% of DRI. The carbohydrate content was 13.0±1.21% while 7.42±0.41% was fibre. The carbohydrate fraction showed a 10% of contribution to DRI of carbohydrate. Similarly, the nut showed an energy value of 580.56 kcal/100 g indicating it as a good source of energy. The TA kernel showed high mineral content, specifically Na, K, Ca, Fe, Zn and Mg contents were 72.5, 123.25, 643.5, 32.25, 11.45 and 46.25 mg/100 g respectively. The high K, Ca and Fe content with low Na content was a good indication in terms of human nutrition. Moreover, TA nut showed antioxidant activity with an IC50 of 53.77±3.44 mg/ml for DPPH, 7.68±1.23 mg/ml for ABTS and reducing power of 230.57±9.65 mM Trolox eq/100 g in FRAP assays. Hence, TA nut could be recommended as an excellent source of protein, micronutrients and energy along with high antioxidant capacities which is beneficial to improve the nutritional status of the Sri Lankans with value addition.