【作者】 徐金瑞；

【导师】 刘兴华；

【作者基本信息】 西北农林科技大学 ， 食品科学， 2003， 硕士

【摘要】 果胶生产目前在我国尚处于起步阶段，主要原因是传统的用酒精沉淀的生产方法成本过高，而低成本的盐析方法在技术上还不成熟。本研究立足于这一现状，以榨汁干燥后的苹果渣为研究材料，采用酸解盐析法对苹果渣中果胶的提取工艺及纯化技术进行研究，主要包括萃取剂的选择、提取果胶最佳工艺参数的确定、脱色方法的比较、糖和蛋白质脱除方法的初步尝试、盐析法沉淀果胶工艺参数确定、脱盐条件等。研究结果表明： ①用本试验所用的果渣提取果胶，应选用H₃PO₄和H₂SO₃混合酸（1：2）作为萃取剂调节溶液的pH值，所得粗果胶无论是产率还是色泽都优于其它酸萃取的效果。 ②以630nm吸光度作为果胶溶液色度的指标；采用咔唑硫酸比色法，在530nm时测定果胶液的吸光度计算溶液中果胶得率。 ③酸解法提取果胶的最佳工艺参数为：温度95℃、pH 2.0、时间2.0h、料液比1：12；在此条件下测得粗果胶的提取率为14.62％。 ④用树脂脱色比用活性炭脱色效果好，所得产品无论得率还是质量都优于活性炭脱色，尤其是该方法适宜于工业化生产；对于试验所用规格的层析柱，树脂脱色的最佳工艺参数为：温度60℃，流速200ml/h。 ⑤采用透析法脱糖脱除率可达到96.35％左右；三氯乙酸法可脱除61.49％左右的蛋白质，果胶的损失率仅3.40％。试验尝试的纯化技术基本可行。 ⑥确定Al₂（SO₄）₃为沉淀果胶最佳的盐，盐析的最佳工艺条件为：每100ml果胶液加6mlAl₂（SO₄）₃饱和溶液，边均匀搅拌边用浓氨水调pH至4.5左右，60℃保温1h。 ⑦脱盐条件：每5g果胶盐置于200ml脱盐液（组分为60％乙醇+3％盐酸+37％水，V/V）中，脱盐30min左右，所得果胶产量0.7645g、灰分含量4.34％。 本研究的创新之处： ①比较全面系统地研究了低成本生产果胶的技术条件。 ②对纯化技术作了进一步探讨，尤其对果胶的脱色技术提出了新的见解。 ③本研究为果渣资源的综合利用提供了应用依据和技术支持。更多还原

【Abstract】 At present, the production of pectin in China is still lagging. Because the traditional production in which ethanol is the precipitant costs higher, but the technology of salting out which costs lower is not prefect. Based upon the present condition, we studied the extracting and purifying technology about pectin from apple pomace. It involved the following aspects: choosing the optimal acidolysis reagent, determining the optimal parameters of extracting technology of pectin, comparing the effect of pectin decoloration, attempting the methods of purification, determining the optimal parameters of technology of pectin precipitation with salt, determining the condition of desalting, etal. The result shows:(1) The value of pH of solution should be adjusted with phosphoric acid and sulphurous acid (1:2) at extracting pectin from apple pomace,and the pectin with the best color and quality was obtained.(2) The absorbance at 630nm is the index of transmittancy of pectin solution. The yield of pectin can be converted by absorbance of pectin solution by the method of carbazole colorimetric at 530nm.(3) The optimal parameters of pectin extracted by acid are :95℃,pH 2.0, 2.0h,the ratio of pomace and water 1:2.At the above condition, the yield of unrefined pectin is 14.62%.(4) The effect of decoloration with resin is better than active carbon, and the method of decoloration with resin is suitable for industrial production. At the condition of the test, the optimal parameters of decoloration with resin are: temperature 60℃, velocity of flow speed 200ml/h.(5) The carbohydrate can be removed about 96.35% by dialysis, the protein can be removed about 61.49% by the method of trichloroacetic acid , and the loss rate of pectin is only 3.40%. The method of purification applied in the test is practicable.(6) The aluminum sulfate is determined as the optimal precipitant in precipitating pectin, the optimal condition of salting out is: adding 6ml saturated solution of aluminum sulfate into 100ml pectin solution, adjusting the value of pH to 4.5 with ammonia water, and keeping Ih at 60 ℃.(7) The optimal proportion of solution of desalting(v/v) is:60% ethanol + 3% hydrochloric+37% water, adding 5g pectin dried into 200ml solution of desalting, and stirring for about 30min.Under this condition, the yield of pectin is 0.7645g; the ash content is 4.34%.The new ideas brought forth in the study are:(1) The technical condition of producing pectin with less cost was systematically studied.(2) The purification technology of pectin was attempted in this study, especially new opinion was brought forth on decoloration of pectin.(3) The study can provide application foundation and technical support for comprehensive utilization of apple pomace.更多还原