Polysaccharide with antioxidant, α-amylase inhibitory and ACE inhibitory activities from Momordica charantia

• Novel functional polysaccharide was extracted from Momordica charantia.
• It is an acidic heteropolysaccharide with a molecular weight of ∼92 kDa.
• It mainly comprises of glucose, galactose and galaturonic acid.
• High emulsifying, foaming and thickening capacities were observed.
• It exhibited α-amylase and angiotensin converting enzyme inhibitory activities.

Functional polysaccharide was isolated from Momordica charantia, with a yield of 36% (w/w). M. charantia bioactive polysaccharide (MCBP) was an acidic and branched heteropolysaccharide with a molecular weight of 92 kDa. Fourier transform infrared spectroscopic analysis indicated that MCBP was a pectin-like polysaccharide with an esterification degree of 53% and it contains numerous monosaccharides, predominantly glucose, galactose, and galaturonic acid. The results also showed that MCBP exhibited free radical scavenging activity (31.9%), ferric reducing antioxidant power (0.95 mM), α-amylase inhibition (89.1%), and angiotensin-converting enzyme inhibition (94.1%). In the terms of functionality, MCBP showed a lower water-holding capacity but higher in oil-holding capacity, emulsifying activity and foaming capacity compared to citrus pectin. Scanning electron microscopy images demonstrated that MCBP formed gels with a porous structure, and flow analysis showed that the gel solution exhibited pseudoplastic shear-thinning behavior. These findings indicated that MCBP is a promising functional macromolecular carbohydrate for the food and nutraceutical industries.