title: Antioxidant activity and emulsion-stabilizing effect of pectic enzyme treated pectin in soy protein isolate-stabilized oil/water emulsion.
abstract: The antioxidant activity of pectic enzyme treated pectin (PET-pectin) prepared from citrus pectin by enzymatic hydrolysis and its potential use as a stabilizer and an antioxidant for soy protein isolate (SPI)-stabilized oil in water (O/W) emulsion were investigated. Trolox equivalent antioxidant capacity (TEAC) was found to be positively associated with molecular weight (M(w)) of PET-pectin and negatively associated with degree of esterification (DE) of PET-pectin. PET-pectin (1 kDa and 11.6% DE) prepared from citrus pectin after 24 h of hydrolysis by commercial pectic enzyme produced by Aspergillus niger expressed higher α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, TEAC, and reducing power than untreated citrus pectin (353 kDa and 60% DE). The addition of PET-pectin could increase both emulsifying activity (EA) and emulsion stability (ES) of SPI-stabilized O/W emulsion. When the SPI-stabilized lipid droplet was coated with the mixture of PET-pectin and pectin, the EA and ES of the emulsion were improved more than they were when the lipid droplet was coated with either pectin or PET-pectin alone. The amount of secondary oxidation products (thiobarbituric acid reactive substances) produced in the emulsion prepared with the mixture of SPI and PET-pectin was less than the amount produced in the emulsion prepared with either SPI or SPI/pectin. These results suggest that PET-pectin has an emulsion-stabilizing effect and lipid oxidation inhibition ability on SPI-stabilized emulsion. Therefore, PET-pectin can be used as a stabilizer as well as an antioxidant in plant origin in SPI-stabilized O/W emulsion and thus prolong the shelf life of food emulsion.
authors.affiliation: Department of Food Science, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan.
authors.forename: Ping-Hsiu
authors.initials: PH
authors.lastname: Huang
authors.forename: Hao-Te
authors.initials: HT
authors.lastname: Lu
authors.forename: Yuh-Tai
authors.initials: YT
authors.lastname: Wang
authors.forename: Ming-Chang
authors.initials: MC
authors.lastname: Wu
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D002957:Citrus / Q000737:chemistry; D004355:Drug Stability; D045703:Emulsifying Agents; D004655:Emulsions / Q000737:chemistry*; D006868:Hydrolysis; D010368:Pectins / Q000378:metabolism* / Q000494:pharmacology*; D011133:Polysaccharide-Lyases / Q000378:metabolism; D030262:Soybean Proteins / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D045703:Emulsifying Agents; D004655:Emulsions; D030262:Soybean Proteins; D010368:Pectins; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase; D011133:Polysaccharide-Lyases; C027349:pectin lyase