Physicochemical And Processing Properties Of Tofu Taro Pectin Polysaccharid

Pectin is a large polysaccharide widely found in plants and has four main structures: homogalacturonan(HG),rhamnogalacturonan type I(RG-Ⅰ),rhamnogalacturonan type II(RG-Ⅱ)and xylogalacturonan(XGA).Pectin has good processing properties,so it is often used as an emulsifier and gelling agent in food processing,but at present the raw materials for industrial production of pectin are mainly apples and citrus,which is difficult to meet the increasing demand for pectin applications,so the development of new raw materials for pectin production and the discovery of excellent properties of pectin has become a research hotspot.Tofu Chai is a wild resource rich in herbs,folk often use its rich pectin content as a raw material for the traditional cuisine "fairy tofu",so the pectin in the leaves of Tofu Chai has greater development value,but the current research on Tofu Chai pectin is mainly focused on the optimization of the extraction process,the functional properties of Tofu Chai pectin However,the current research on tofu wood pectin is mainly focused on the optimization of the extraction process,and the functional properties of tofu wood pectin are less studied,which limits the development and utilization of tofu wood pectin.Therefore,in this study,pectin polysaccharides were extracted and purified from tofu chai leaves,and their emulsification and gelation properties were compared with those of traditional commercial citrus pectin.The main research results are as follows.1.Pectin was extracted from the leaves of Tofu Chai using ultrasound-assisted citric acid,decolourised using resin,purified by chemical protein removal,dialysis and column chromatography to obtain Tofu Chai pectin polysaccharides.The yield of crude pectin was 21.37%±2.09%,the decolourisation rate of the macroporous resin was 83.57%±3.01% and the retention rate of pectin was 82.85%±1.76%,with good decolourisation and low loss of pectin.The physicochemical indexes of the pectin polysaccharides obtained by this method were 6.25%±1.03% dry loss,0.27%±0.09%acid insoluble component and 71.35%±0.11% total galacturonic acid,all of which met the GB25533-2010 standard for commercial pectin.The esterification degree of pectin polysaccharide is 64.67%±0.78%,which belongs to high ester pectin.The numerical average molecular weight of pectin polysaccharide was 112.3 k Da,and the weight average molecular weight of Mw was 233.4 k Da.The infrared spectra also showed the characteristic absorption peak of pectin polysaccharide.2.To study the emulsification properties of bean curd pectin polysaccharide emulsions under the influence of different factors,the results show that the emulsification activity and stability of bean curd pectin polysaccharide emulsions are significantly affected by the mass concentration of pectin polysaccharide and the volume fraction of the oil phase,emulsification activity and stability increase with the increase in mass concentration and volume fraction of the oil phase.The emulsification index was significantly influenced by the volume fraction of oil phase,and the emulsification index decreased rapidly when the volume fraction of oil phase was increased.The highest emulsifying activity and stability of the pectin emulsions were 57.70% ± 0.33% and 55.18% ± 0.26%,while the highest emulsifying activity and stability of the commercial citrus pectin emulsions were 48.62% ± 0.29% and48.86% ± 0.17%,and the emulsion uniformity of the droplets in the pectin emulsions was also better than that of the commercial citrus pectin emulsions.The emulsification characteristics of tofu chai pectin polysaccharide were better than those of commercial citrus pectin.The gel characteristics were studied under the influence of different factors.The results show that Ca2+ has the best effect on gel strength and water retention;with the increase of pectin mass concentration,the gel strength and water retention of Tofu Chai pectin polysaccharide gradually increased;the gel strength and water retention were the highest at metal ion concentration 0.06 mol/L,soluble solids mass concentration 20% and p H 4.2.The gelation properties of tofu chai pectin polysaccharides were also stronger than those of commercial citrus pectin.Based on the good physicochemical properties and processing characteristics of tofu chai pectin polysaccharide,this study developed a new red orange jelly using tofu chai pectin polysaccharide as raw material combined with characteristic red orange resources.The resulting jelly was bright in colour,unique in flavour and in good condition,and complied with the GB19299-2015 executive standard for jelly.The jelly was determined to contain 0 fat and protein,86.3 g/100 g of moisture,0.56 g/100 g of ash,23.3 g/100 g of carbohydrates and 97.9 k J/100 g of standard calories,which is a high-moisture,low-energy,zero-fat,zero-protein food and can be used as a functional food for people on a diet.