具有不同甲氧基化程度的低甲氧基果胶(LMP)(DM,40-50%,20-30%和5-10%)由市售柑橘果胶使用高静水压辅助的酶促(HHP-果胶)和传统的碱性(A-果胶)脱酯化方法制备。结果表明,去酯化方法和DM均表现出不同理化性质的LMPs,结构,和功能属性。随着DM的减少,LMP显示分子量(Mw)降低,虽然负电荷和鼠李糖半乳糖醛酸I(RG-I)比率增加,伴随着更好的乳液稳定性,乳液的凝胶强度和保水性。相对于A-果胶,HHP-果胶具有较高的Mw和较低的RG-I侧链比,有助于其更好的热稳定性,表观粘度,和乳化特性。DM较低的HHP-果胶(5-10%)显示出优越的增厚,乳化和乳化特性,而具有较高DM(40-45%)的具有优异的热稳定性,这为果胶的去酯化和有针对性的结构修饰提供了替代方案。
Low methoxyl pectin (LMP) with different degree of methoxylation (DM, 40-50 %, 20-30 % and 5-10 %) were prepared from commercially available citrus pectin using high hydrostatic pressure assisted enzymatic (HHP-pectin) and traditional alkaline (A-pectin) de-esterification method. The results showed that both de-esterification methods and DM exhibited LMPs with varied physicochemical, structural, and functional properties. As the DM decreased, LMP showed a decrease in molecular weight (Mw), while an increase in negative charges and rhamnogalacturonan I (RG-I) ratio, accompanied with better emulsion stability, emulsion gel strength and water-holding properties. Relative to A-pectin, HHP-pectin had higher Mw and lower RG-I side chain ratio, contributing to its better thermal stability, apparent viscosity, and emulgelling properties. HHP-pectin with lower DM (5-10 %) showed superior thickening, emulsifying and emulgelling properties, while that with higher DM (40-45 %) had superior thermal stability, which provided alternative for de-esterification and targeted structural modification of pectin.