A new functional protein‑polysaccharide conjugate based on protein concentrate from sesame processing by-products: Functional and physico-chemical properties

Ardeh or Tahin residue, a by-product from oil extraction and processing of dehulled, roasted and milled sesame, contains a high amount of proteins. In this research, the protein was extracted as sesame protein concentrate (SPC) and its physicochemical and functional properties were investigated. In order to improve the functional properties of sesame protein concentrate, SPC-maltodextrin conjugates (SMC) were prepared. The conjugated substance was analyzed by means of different instrumental techniques. The covalent attachment of maltodextrin to SPC was confirmed by Fourier transform-infrared analysis and SDS gel electrophoresis. The protein exhibited a poor solubility that was affected by pH, while conjugation significantly enhanced the solubility providing a soluble substance in a wide range of pH. The emulsifying capability of SMC was higher than that of SPC and emulsions with smaller droplet sizes were obtained. Circular dichroism spectroscopy showed that the secondary structures were changed significantly by conjugation. Structural flexibility of the molecules was increased, improving the functional characteristics of the protein. The results showed that Ardeh residue could be a potential alternative renewable plant protein source to be used as a food ingredient for the enhancement of food nutritional value and quality especially after conjugation with maltodextrin.