果胶甲酯化反应及应用高甲氧基果胶制备纳米乳液  

Pectin methoxylation and its application in preparation high methoxyl pectin nano-emulsion

作　　者：丁萍 汪明明[1] 迟坤蕊 华霄[1,2] 杨瑞金[1,2] DING Ping;WANG Ming-ming;CHI Kun-rui;HUA Xiao;YANG Rui-jin(School of Food Science and Technology,Jiangnan University,Wuxi 214122,China;State Key Laboratory of Food Science and Technology,Jiangnan University,Wuxi 214122,China)

机构地区：[1]江南大学食品学院,江苏无锡214122 [2]江南大学食品科学与技术国家重点实验室,江苏无锡214122

出　　处：《食品与发酵工业》2018年第8期188-195,共8页Food and Fermentation Industries

基　　金：国家自然科学基金青年基金(31501433);国家自然科学基金重点项目(31230057)

摘　　要：以商业橘皮果胶为原料,在无水甲醇环境中采用盐酸催化甲酯化反应制备高甲氧基果胶。通过对反应时间、反应温度、料液比以及盐酸添加量的调节,可以制备得到酯化度在90%以上的高甲氧基果胶。分子质量分布结果表明,随着反应温度升高、反应时间延长和盐酸浓度增加,产物的酯化度逐渐提高,但数均分子质量逐渐降低。在料液比1∶50,盐酸添加量0.1 mol/L,温度60℃下反应12 h,产物酯化度达到91.20%,但数均分子质量降低为15.00 kDa。基于极高酯化度果胶所具有的双亲性(甲氧基为疏水基团而羟基为亲水基团)和分子链短的特点,进一步研究了极高酯化度果胶的乳化性质。用高能量法(高速剪切)分别制备了油滴体积分数为10%、20%和30%的纳米乳液,并考察了7 d内乳状液的稳定性、粒径和Zeta-电位变化。结果显示采用极高酯化度果胶可制备得到粒径为3 500 nm的乳状液(油滴体积分数10%~30%),并具有较好的稳定性。Methoxylation of commercial citrus pectin in anhydrous methanol catalyzed by HCl was conducted.Reaction conditions including reaction time,temperature,solid-to-liquid ratio(SLR)and HCl concentration were investigated and optimized.High methoxyl pectins with various degree of methoxylation(DM)of>90%were obtained.Results of molecular weight distribution showed that DM was improved with the increase of reaction temperature,reaction time and acid concentration,but the number-average molecular weight was decreased.Particularly,HMP with DM of(91.20±0.13)%was obtained under SLR 1∶50(w/v)at 60℃with 0.1 mol/L HCl for 12 h,and the M w was decreased to 15.00 kDa.Furthermore,extremely high DM emulsification properties were studied due to its amphiphilic property(by hydrophobic methoxyl groups and hydrophilic hydroxyl groups)and short molecular length.Nano-emulsions withφ(oil)=10%-30%were prepared by high energy method(high speed shearing)and their 7-day stability,Zeta-potential and particle size were characterized.Emulsion of 3 500 nm with good stability was produced by high methoxyl pectin with DM of 91.20%.

关 键 词：高甲氧基果胶:甲酯化反应 酯化度 乳化 粒径 乳液稳定性 

分 类 号：TS201.7[轻工技术与工程—食品科学]