A Short Extraction Time of Polysaccharides from Fenugreek (Trigonella foencem graecum) Seed Using Continuous Ultrasound Acoustic Cavitation: Process Optimization, Characterization and Biological Activities

Abstract

In this study, the effective variables involved in ultrasound-assisted extraction (UAE) of fenugreek (Trigonella foenum graecum) seeds polysaccharides (FSPs) were optimized through Box–Behnken response surface design. The maximum yield of FSPs was 33.49% under the modified optimum conditions of an ultrasound power of 120 W, an irradiation time of 22 min and a liquid-to-solid ratio (L/S) of 30:1 mL g−1. The predicted yield was in a very good agreement with the experimental yield of 33.41%. This value was higher than the FSPs yield obtained using conventional extraction (CE) method for 180 min at the same extraction temperature and L/S ratio. The primary chemical and structural characteristics were investigated by UV, FT-IR, and GC-MS. FSPs found to be a heteropolysaccharide consisted of galactose (38.18%), glucose (3.71%), mannose (46.13%), rhamnose (1.02%), and arabinose (0.83%). Furthermore, the FSPs exhibited considerable scavenging activity against 1,1-Diphenyl-2-Picrylhydrazyl free radicals and ferric reducing antioxidant power and reducing power, in a concentration-dependent mode in vitro. Our results suggested that UAE technique gave a higher yield of FSPs with a shorter extraction time than the CE and FSPs can also be used as promising resources of natural agent for functional foods and medicinal industries.