Food Potential and Antioxidant Property of Cassia auriculata Seed: A Nutritionally Unexploited Legume

Abstract

Background: Seeds of Cassia auriculata are reported to be used for varying medicinal purposes; however, information on nutritive value and physical properties of seeds remains unexplored. Hence, this study is carried out to investigate the proximate, minerals, fatty acid profile, functional properties, phenolic profiling as well as antioxidant activities of seed in order to give adequate information on its suitability as a possible future food source. Methods: The proximate compositions were evaluated by AOAC, and other standard prescribed methods. Minerals and fatty acids compositions were determined using Atomic Absorption Spectrophotometer and UV-visible spectrophotometers, while anti-nutrient determinations were carried out using standard procedures. Antioxidant activity and phenolic profiles were also analyzed using UVvisible spectrophotometers and HPLC. Results: The results obtained from proximate analysis were: moisture content (9.74%), ash content (4.95%), protein (23.83%), lipid (6.68%), crude fiber (8.93%), total soluble sugars (53.4%) and energy value (412.6 Kcal/100g). The mineral analysis showed that nitrogen, potassium and phosphorus were the predominant elements present in the seeds. Calcium, zinc, sodium, magnesium, copper, and iron were also detected in appreciable amounts. The analyzed anti-nutritional factors were oxalate (1.38 μg/mg), phytate (0.12 μ g/mg), tannin (3.02 μg/mg), phenol (1.11 μg/mg) and saponins (0.0037%). In the seeds oils, palmitic acid (14.01%) was prominent saturated fatty acid followed by stearic acid (5.12%) and arachidic acid (2.17%), while oleic acid (21.31%) and linoleic acid (51.52%) constituted the dominant unsaturated fatty acids. The physicochemical and functional properties revealed that the seeds flour had excellent water absorption index, swelling index, foaming capacity and foam stability. In addition to that, the flour extracts revealed the dose-dependent antioxidant properties of tested extracts of the seed flour. Moreover, the HPLC analysis unveiled four phenolic compounds namely, benzoic acid (0.72 μg/mg), cinnamic acid (0.71 μg/mg), salicylic acid (0.65 μg/mg) and vanillic acid (0.61 μg/mg). Conclusion: The results of the present study revealed that Cassia auriculata seed flour is a good source of important nutrients such as fat, protein, fibre and minerals along with edible phenolics. So the seeds would be a valuable source of dietary supplements especially for growing population and could be used for industrial and pharmaceutical purposes.