【摘要】：甘薯是我國第四大產(chǎn)量的糧食作物,在工業(yè)上主要用來生產(chǎn)淀粉及淀粉類產(chǎn)品,在此過程中產(chǎn)生大量薯渣。通常情況下,薯渣被作為飼料簡單利用或作為廢物丟棄,造成環(huán)境污染和資源浪費(fèi)。薯渣中含有豐富的果膠資源,但目前對甘薯果膠的研究很少。本研究首先采用磷酸氫二鈉法提取甘薯果膠并對其工藝進(jìn)行了優(yōu)化,然后采用離子交換樹脂法對最優(yōu)提取條件下所得果膠進(jìn)行了純化。最后分別采用酸法和磷酸氫二鈉法最優(yōu)工藝提取甘薯果膠,進(jìn)而采用超濾、酒精沉淀和離子交換樹脂法純化果膠,對不同提取、純化方法所得甘薯果膠的組成和凝膠特性進(jìn)行比較分析。結(jié)果如下: 1)以薯渣為原料,采用磷酸氫二鈉法提取甘薯果膠,在單因素試驗(yàn)基礎(chǔ)上,通過二次回歸正交旋轉(zhuǎn)組合試驗(yàn)探討了液料比、提取時(shí)間、提取溫度和溶液pH對果膠得率的影響,確定最優(yōu)的提取條件為:液料比20:1,提取時(shí)間3.3 h,提取溫度66℃和溶液pH 7.9。在此提取條件下,果膠得率為10.24%。最優(yōu)工藝條件下制備果膠半乳糖醛酸含量為60.02±0.03%,淀粉、灰分含量分別為10.42%和10.58%。 2)采用離子交換樹脂法對磷酸氫二鈉法最優(yōu)提取條件下所得果膠粗提液進(jìn)行純化,以果膠得率、灰分含量和果膠脫色效果為指標(biāo),從001×7、201×7、D001和D201中篩選出D001和D201兩種離子交換樹脂,組成D001-D201串聯(lián)式離子交換柱。進(jìn)一步考察D001-D201離子交換柱在不同上樣液流速下的果膠得率、灰分含量和果膠脫色效果,篩選確定最佳上樣液流速為1 BV/h。在最佳離子交換樹脂純化條件下,果膠半乳糖醛酸含量從60.02%上升至65.02%,果膠流出液相對顏色從0.384顯著下降至0.124,果膠灰分含量從10.58%顯著下降至3.2%,特別是果膠中磷含量從19,000 ug/g顯著下降至0.11 ug/g。表明采用離子交換樹脂法對果膠粗提液有一定脫色效果,可降低果膠灰分含量,提高果膠純度。 3)采用磷酸氫二鈉法制備果膠得率(7.2-9.7%)高于酸法制備果膠(4.6-7.0%),分子量和凝膠強(qiáng)度分別為480.6-1201.0 kDa和61.9-278.1 g/cm~2,均高于酸法制備果膠的250.8-771.1 kDa和149.4-534.0 g/cm~2。磷酸氫二鈉法制備果膠的酯化度為9.08-10.4%,低于酸法制備果膠的28.7-31.11%。 4)采用磷酸氫二鈉法提取果膠,離子交換樹脂法所得果膠半乳糖醛酸含量(65.0%)顯著高于超濾和酒精沉淀法(45.0-51.5%),灰分含量(3.2%)顯著低于超濾和酒精沉淀法(9.6-10.6%),中性糖含量最低為22.6%,且凝膠強(qiáng)度最高為534.0 g/cm~2。但離子交換樹脂法所得果膠分子量(1098.0 kDa)顯著低于超濾法純化果膠(1201.0 kDa)。 5)采用酸法提取果膠,超濾法純化果膠半乳糖醛酸含量(63.1%)顯著高于酒精沉淀和離子交換樹脂法(57.1-58.5),中性糖含量(16.3%)顯著低于酒精沉淀和離子交換樹脂法(20.2-22.6%),分子量和凝膠強(qiáng)度最高,分別為771.1kDa和278.1g/cm~2。
[Abstract]:Sweet potato is the fourth largest grain crop in China. It is mainly used to produce starch and starch products in industry. Generally, potato residue is simply used as feed or discarded as waste, resulting in environmental pollution and waste of resources. There are abundant pectin resources in potato dregs, but there are few researches on sweet potato pectin. In this study, the pectin of sweet potato was extracted by hydrogen disodium phosphate method and optimized, then the pectin was purified by ion exchange resin method. Finally, the optimum technology of acid method and hydrogen phosphate disodium method was used to extract pectin from sweet potato, and then to purify pectin by ultrafiltration, alcohol precipitation and ion exchange resin. The composition and gel properties of sweet potato pectin obtained by purification method were compared and analyzed. The results are as follows: 1) using potato dregs as raw material, using hydrogen phosphate disodium method to extract sweet potato pectin. On the basis of single factor experiment, the ratio of liquid to material and extraction time were studied by quadratic regression orthogonal rotation combination test. The effects of extraction temperature and solution pH on pectin yield were determined. The optimum extraction conditions were as follows: ratio of liquid to material 20: 1, extraction time 3.3 h, extraction temperature 66 鈩，

本文編號(hào)：2406275