【作者】 王晰锐；

【导师】 江连洲；

【作者基本信息】 东北农业大学 ， 食品科学， 2011， 硕士

【摘要】 紫甘薯属旋花科一年生草本植物,是新近开发出的一类优良特异的甘薯品种。紫甘薯花色苷（Purple Sweet Potato Anthocyanins,PSPA）是从紫甘薯的块根中浸提出来的一种天然红色素,它无毒,无特殊气味,具有多重营养、药理和保健功能,是一种开发前景广阔的天然食用色素资源。本实验对紫甘薯花色苷进行了结构鉴定,同时对其稳定性以及功能性进行了研究。1用HPLC-MS联用法鉴定了中国5个主要紫甘薯种植品种中花色苷的含量及组分。5个品种包括紫薯038、群紫、京6、济18以及紫罗兰。结果显示紫薯038提取物中的花色苷含量是最高的,为9.66mg/g·dw。从这5个品种中共鉴定出12种花色苷组分,每个品种的组分各有差异,并分别从紫薯038和济18中发现一种新花色苷组分,其质荷比（m/z）为1083,推测其结构可能为芍药素3-阿魏酰-对羟基苯甲酰槐糖苷-5-葡糖苷。2采用HPLC-MS法测定3种加工方法对紫甘薯（美国黑紫）花色苷含量及其组成的变化。结果表明,采用烤薯、炸薯以及蒸薯3种加工方法均降低紫甘薯花色苷含量,其花色苷残余率分别为炸薯（93.7%）、蒸薯（87.1%）和烤薯（60.0%）,进一步研究发现紫甘薯中双酰化的花色苷稳定性高于单酰化花色苷,咖啡酸酰化的花色苷组分稳定性高于对羟基苯甲酸酰化花色苷。结论:炸和蒸的加工方法能有效维持紫甘薯花色苷含量。3实验研究了pH值、温度、金属离子以及食品添加剂对紫甘薯花色苷稳定性的影响。结果表明,pH影响花色苷的稳定性,pH6.0时花色苷降解最快,pH4.0时紫甘薯花色苷最稳定;低温能显著保持紫甘薯花色苷的稳定性。Fe³⁺对花色苷稳定性无明显影响;K⁺、Ca²⁺、Mg²⁺、Cu2+使花色苷的吸光度增加,具有增色作用,同时还能增加紫甘薯花色苷的稳定性;葡萄糖对紫甘薯花色苷具有一定的增色作用,同时起到一定的稳定作用;山梨酸钾对紫甘薯花色苷稳定性无显著性影响;过氧化氢对紫甘薯花色苷具有明显的破坏作用;Vc对紫甘薯花色苷具有一定的增色作用,但对其稳定性有破坏作用。4本文从还原能力和对自由基清除能力等方面对紫甘薯花色苷的抗氧化能力进行了试验研究。结果表明:紫甘薯花色苷具有一定的还原能力,对ABTS自由基均具有较强的清除作用。在试验浓度范围内,其对应的最大清除率为53.15%。此外,本文采用荧光光谱法研究了6个品种紫甘薯花色苷对DNA的保护作用。利用EB（溴化乙锭）作为荧光探针,测定紫甘薯花色苷存在时,DNA与EB混合液的荧光强度。结果表明,紫甘薯花色苷对DNA有保护作用,并且随着紫甘薯花色苷含量的增加荧光强度逐渐降低。更多还原

【Abstract】 Purple sweet potato, convolvulaceae, was a special kind of sweet Potato with mauve flesh.Anthocyanins from Purple sweet potato（Purple Sweet Potato Anthocyanins,PSPA）, which were nontoxic and multi-functional sueh as nutrition, pigmentation, health protection, had broad future of development.The aim of this work was to tentatively identify anthocyanins from purple sweet potato using HPLC-MS and study the stability and function of anthocyanidin from Purple sweet potato.1. Anthocyanins from five Chinese purple sweet potato varieties were analysed and tentatively identified using HPLC-MS. the anthocyanin content of purple sweet potato 038 extract is the highest, 9.66mg/g.Twelve different anthocyanins were identified from the five varieties. The component of each varieties varies. Moreover, a new component was isolated from purple sweet potato 038 and ji18, respectively. The mass charge ratio （m/z） is 1083. Its structure was tentatively identified as peonidin-3-feruloyl-p-hydroxybenzoylsophoroside-5-glucoside.2. The anthocyanin content and compositions of the purple sweet potato was evaluated by HPLC-MS methods. Results: Each treatment decreased the anthocyanin content. The anthocyanin residual rate of the frying, steaming, and roasting were 93.7%, 87.1%, and 60.0%, respectively. Moreover, the diacylated anthocyanin showed a stronger stability than the acylated ones. The stability of the caffeoyl anthocyanin was stronger than that of the hydroxybenzoyl anthocyanin. Conclusion: The frying and steaming were effective to hold the anthocyanin content of the purple sweet potato.3. Anthocyanin stability of Anthocynins from Purple Sweetpotato was studied at different temperature,pHs,metallic ion and food additive.The result shows that the stability of anthocyanin from purple sweet potato significantly affected by pH value. And its degradation rate is the fastest at pH 6.0 and the lowest at pH 4.0. Low temperature is effective in maintain the stability of anthocyanin from Purple Sweet Potato. Fe³⁺ had no effect on the stability of anthocyanins. K⁺、Ca²⁺、Mg²⁺、Cu²⁺ had enhanced the stability of purple sweetpotato anthocyanins. Glucose had a certain color enhancement function. Potassium sorbate had no effect on the stability of anthocyanins.Hydrogen peroxide were obviously harmful to the stability of purple sweet potato; Vc had a certain color enhancement function, but is harmful to the stability of it.4. In this paper, the antioxidant activities of Anthocynins from purple sweet potato were studied and evaluated by determining the reducing capacity, free radical-scavenging activity on ABTS. The results showed that they had stronger reducing capacity and scavenging effects on ABTS radical. In the range of test concentration, the maximum scavenging was 53.15%. In addition, the protection of anthocyanin of purple sweet potato on DNA were investigated by spectrofluorometric method. Fluorescence integration intensity of DNA and Ethidium Bromide（EB） mixture in the presence of total anthocyanin were determined. The results showed that anthocyanin of purple sweet potato can protect DNA. In addition, The fluorescence intensity of DNA-EB compound was decreased gradually along with the addition of anthocyanin contents of purple sweet potato.更多还原