Department of Food Science, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan.
J Agric Food Chem. 2011 Sep 14;59(17):9623-8. doi: 10.1021/jf202020t. Epub 2011 Aug 9.
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.
研究了果胶酶处理果胶（PET-果胶）的抗氧化活性及其作为稳定剂和抗氧化剂在大豆分离蛋白（SPI）稳定的水包油（O/W）乳液中的潜在应用。发现 Trolox 当量抗氧化能力（TEAC）与 PET-果胶的分子量（M(w)）呈正相关，与 PET-果胶的酯化度（DE）呈负相关。由黑曲霉表达的商业果胶酶水解 24 小时后从柑橘果胶制备的分子量为 1 kDa 和 DE 为 11.6%的 PET-果胶，比未经处理的柑橘果胶（353 kDa 和 60% DE）具有更高的α,α-二苯基-β-苦基肼（DPPH）自由基清除活性、TEAC 和还原能力。PET-果胶的添加可以提高 SPI 稳定的 O/W 乳液的乳化活性（EA）和乳液稳定性（ES）。当 SPI 稳定的脂滴用 PET-果胶和果胶的混合物包被时，乳液的 EA 和 ES 比单独用果胶或 PET-果胶包被时得到了改善。用 SPI 和 PET-果胶混合物制备的乳液中产生的次级氧化产物（硫代巴比妥酸反应物质）的量少于用 SPI 或 SPI/果胶单独制备的乳液中产生的量。这些结果表明，PET-果胶对 SPI 稳定的乳液具有乳化稳定作用和抑制脂质氧化的能力。因此，PET-果胶可作为稳定剂和抗氧化剂用于 SPI 稳定的 O/W 乳液中，从而延长食品乳液的保质期。
