Nutritional profiling and crude polysaccharide extraction from Nymphaea nouchali to evaluate the acid digestibility as prospective source of functional food

Abstract

Food cravings for processed food, consumption of low level of nutrients and carcinogenesis of chemical substances used in food have made a demand of functional food from natural resources in recent days. This study evaluates the nutraceutical and pharmacological profile of the stem of N. nouchali (SPN) (English name: Waterlily) of Bangladesh to establish an affordable diet. SN powder (SPN) has 13.048 ± 0.053% moisture, 14.809 ± 0.215% ash, 1.429 ± 0.029% crude-fat, 17.75 ± 0.675% crude fiber evaluated by proximate analysis primitively. Subsequently, the content of Na, K, Ca was estimated by Flame Photometric method whereas the iron content was measured by colorimetric method. Delving deeper, the phenolic, flavonoid, and total antioxidant content of SPN quantified as 20.388 ± 0.278 mg GAE/100g, 215.201 ± 3.172 mg QE/100g, and 358.374 ± 7.382 mg AAE/100g respectively, analysed by photometric method. HPLC and LCMS method was carried out to identify the presence of gallic acid, catechin, quercetin, p-coumaric acid and rutin in the methanol extract. The methanolic extract of SPN has values of 268.771 ± 5.843 and 97.761 ± 0.039 ppm, distinguished by DPPH scavenging and FRAP assay respectively. Crude polysaccharide was extracted and characterization by FTIR remarks the probable bonds of functional groups. Acid digestibility assay was carried out for the first time in our study, which revealed non-digestibility ranging from 77.465% to 45.06% at lower pH. The nutritional value of our findings and the non-digestible ratio of the crude polysaccharide has proved this as a beneficial source of gut health.