Physicochemical and functional properties of pectic polysaccharides extracted with four different chelators from sesame hull

Abstract

SummarySesame hull is a byproduct of sesame processing and is currently treated as waste, but it could be an important source of pectic polysaccharides. To increase the value of the sesame crop, pectic polysaccharides were extracted from sesame hull using four different chelators, namely trans‐cyclohexane‐1,2‐diamine tetraacetic acid (CDTA), ethylene diamine tetraacetic acid (EDTA), sodium tripolyphosphate (STLP), and sodium hexametaphosphate (SHMP), which were named CSP, ESP, STP, and SHP, respectively. Physicochemical and functional properties were assessed. SHP mainly contained homogalacturonan (HG) linear regions but the others had more branching with rhamnogalacturonan (RG‐I) as the predominant region. CSP showed the highest molecular weight (155 kDa) with a smooth surface. The molecular weight of ESP, STP, and SHP ranged from 40 kDa to 90 kDa and presented cracked surfaces. Furthermore, CSP had the highest oil holding capacity (9.03 g oil g−1 dry matter). ESP showed Newtonian‐fluid characteristics (n = 1.06) and weaker thermal stability than others. STP had the highest viscosity and good emulsifying stability in concentrations of 1% and 2%. SHP showed excellent water holding capacity, foaming capacity, emulsifying stability, and antioxidant activity. This study provides valuable information for selecting a suitable chelator to extract desirable pectic polysaccharides from sesame hull waste.