摘要
我国花生产量位居世界第一，每年花生榨油副产物花生粕约600万吨，目前仅作为饲料或肥料，造成资源严重浪费，而对低值花生粕资源进行高值化利用可以有效应对我国蛋白质资源相对缺乏的困境。花生蛋白饮料营养均衡，味道香浓，深受大众喜爱，但关于花生蛋白饮料生产过程中热杀菌工艺对蛋白结构及消化特性的影响研究较少，此外，花生粕的深加工及高值化利用方式也有待进一步研究开发。 本文以花生蛋白为研究对象，首先探讨了花生分离蛋白-葡萄糖在不同模拟热杀菌条件下的美拉德反应程度，以及杀菌对花生蛋白结构特性的影响。研究结果表明：随着热处理程度加剧，花生分离蛋白-葡萄糖体系的褐变程度和接枝度逐渐升高；当温度升高到121 ℃时美拉德反应程度剧烈加深，反应中间产物更容易向终产物转变，30 min 之后褐变程度逐渐达到最大。通过SDS-PAGE电泳、圆二谱（DC）、热差式扫描量热（DSC）、场发射扫描电子显微镜（FESEM）分析样品的结构，发现热处理后的花生分离蛋白与葡萄糖发生了交联，热稳定性有所提升，焓变值ΔH逐渐降低；二级结构逐渐向有序化发展，变得更加平薄连续；氨酸残基部分被包埋起来，苯丙氨酸残基进一步暴露出来。 然后采用体外模拟胃肠道消化的方法进一步探讨了热杀菌过程对花生蛋白消化特性的影响。实验结果表明：未加葡萄糖的样品热处理后也发生了一定程度的褐变，加入葡萄糖后褐变程度显著加深；随热处理条件加剧，反应程度加深。热处理及美拉德反应致使后续的模拟消化产物中分子量较大的肽段含量增加；
美拉德反应的发生总体上不利于花生分离蛋白的消化利用。在含量超过2%的氨基酸里面，参与美拉德反应活性高的的氨基酸残基主要有Leu、Tyr、Lys、Ile、（Cys）2，其中Lys反应活性最高。
最后系统研究了花生分离蛋白的酶解特性，并进行了鲜味呈味基料的开发研究。研究发现：风味蛋白酶与诺维信11039水解酶按1:2（w/w）复配，底物浓度10%（w/w，按蛋白计），总酶浓度4%（w/w，基于蛋白），酶解pH=7.0 ，酶解温度55 ℃，酶解时间15 h可制备出鲜味突出的花生酶解产物。并且发现添加木糖进行轻度美拉德反应可显著提升花生蛋白酶解产物的鲜味强度，其中花生分离蛋白水解产物-木糖最佳美拉德反应条件如下：木糖添加量0.5%（w/w），反应pH 6.5，反应温度100 ℃，反应时间80 min。
关键词：花生分离蛋白，美拉德反应，热处理，模拟消化，鲜味肽
ABSTRACT
抑菌Peanut production in our country is the first in the world, there are about 6 million tons peanut meal which is peanut oil by-product per year,only as feed or fertilizer. High value utilization of low value peanut meal resources can effectively solve the problem of protein resource lack in our country. Peanut protein beverage has balanced nutrition, aromatic flavor, loved by the masses. But researches on the effect of thermal treatment process on the structures and digestion characteristics
of beverages contain proteins are still relatively lack. At the same time, the processing of peanut meal for more high value using has not formed the scale at present and needs further research and development.
Peanut protein is the research object of this article, discusses the degree of Maillard reaction and the structural characteristics changes of PPI after the simulation of thermal sterilization condition. The results showed that: with the aggravating thermal treatment, browning, intermediate products and degree of graft (DG) increased, indicating that the extent of Maillard reaction (MR) deepened. When the temperature increase to 121 ℃, the extent of Maillard reaction (MR) deepened significantly and intermediate products transform to end-product. Thermal treated for 30 min at 121 ℃, browning extent reaches the maximum. SDS-PAGE, Circular dichroism (CD), Differential scanning calorimetry (DSC) and Field emission scanning electron microscope (FESEM) are employed to characterize secondary structure, tertiary structure, thermal properties and macrostructure changes of PPI. Because of thermal treatment, crosslinking between PPI and glucose come into being, thermal stability is improved, the enthalpy value gradually reduce; Secondary structure of PPI-glucose mixture gradually converts to a more ordered and continuous arrangement; tryptophan residues was encased partly, phenylalanine residues further exposed.
In order to research the effect of thermal sterilization on the subsequent simulated gastrointestinal digestion, PPI and glucose were thermal-treated in thermal sterilization conditions, then subjected to a simulated gastrointestinal digestion in vitro. Absorbance in 294/420 nm of thermal-treated samples, degree of hydrolysis (DH), protein digestibility (PD), molecular weight distribution, free amino acid composition of simulated gastrointestinal digestion products were measured. The results showed that: compared to the control group,
PPI heat-treated without glucose have also been a certain degree of browning, PPI heat-treated with glucose caused stronger MR. with the aggravating thermal treatment, reaction degree deepened. Heat treatment and MR leaded to an increase of larger molecular weight peptides content. From a general view, MR goes against the digestive and utilizable performance of PPI. Amino acids, whose content is more than 2% and have high Maillard reaction activity are Leu、Tyr、Lys、Ile and （Cys）2, Lys has the highest reaction activity among them.
At last, enzyme properties of peanut protein isolate was studied, and the development of umami basic material was conducted. The study found that: the optimal conditions of PPI enzymolysis are as follows: flavor protease and novozymes 11039 hydrolase distribution by 1:2 (w/w), the substrate concentration is 10% (w/w, according to the protein), total enzyme concentration is 4% (w/w, based o
n protein), pH 7.0, enzymolysis temperature is 55 ℃, enzymolysis time is 15 h. And found that mild maillard reaction between enzymatic hydrolysates and xylose can significantly improve the umami strength. The optimal conditions of Maillard reaction are as follows: xylose 0.5% (w/w), pH 6.5, the reaction temperature is 100 ℃, the reaction time is 80 min.
Key words: peanut protein isolate; Maillard reaction; thermal treatment; simulated gastrointestinal digestion;Umami peptide
目录
摘要 ................................................................................................................................... I ABSTRACT .......................................................................................................................... II 第一章绪论.. (1)
1.1 花生资源研究概述 (1)
1.1.1 花生资源概况 (1)
中国饮食文化的发展1.1.2 花生粕资源概况 (1)
1.1.3 花生蛋白资源概况 (3)
1.1.4 花生蛋白饮料概况 (7)
1.2 美拉德反应研究概述 (7)
1.2.1 美拉德反应机理研究概述 (7)
导电胶1.2.2 美拉德反应产物研究概述 (9)
1.3 体外模拟消化研究概述 (12)
1.4 呈味肽制备研究概述 (13)
1.5 本课题研究的立论依据和主要研究内容 (13)
1.5.1 立论依据 (13)
1.5.2 研究内容 (14)
第二章美拉德反应对花生分离蛋白结构特性影响研究 (16)
2.1 引言 (16)
2.2 材料与方法 (16)
2.2.1 材料 (16)
2.2.2 主要仪器 (16)
2.2.3 主要试剂 (17)
2.2.4 试验方法 (17)
2.3 结果与讨论 (20)
2.3.1 花生蛋白的褐变程度和接枝度分析 (20)
2.3.2 SDS-PAGE分析 (21)
2.3.3 二级结构分析 (22)
2.3.4 三级结构分析 (23)
2.3.5 热特性分析 (24)
2.3.6 微观结构分析 (25)
2.4 本章小结 (27)
第三章美拉德反应对花生分离蛋白体外消化特性影响研究 (29)
3.1 引言 (29)
3.2 材料与方法 (30)工业产品生产许可证管理条例
3.2.1 材料 (30)
PPPD298
3.2.2 主要仪器 (30)
3.2.3 主要试剂 (30)
3.2.4 试验方法 (31)
3.3 结果与讨论 (33)
3.3.1 美拉德反应程度分析 (33)
3.3.2 热处理对水解度的影响分析 (34)
3.3.3 热处理对蛋白消化率影响 (36)
3.3.4 肽分子量分布分析 (37)
3.3.5 游离氨基酸分析 (39)
3.4 本章小结 (41)
第四章美拉德反应在制备花生呈味肽中的作用研究 (42)
4.1 引言 (42)
4.2 材料与方法 (42)
交通波4.2.1 材料 (42)
4.2.2 主要仪器 (43)
4.2.3 主要试剂 (43)
4.2.4 试验方法 (43)
4.3 结果与讨论 (48)
4.3.1 酶解花生分离蛋白制备鲜味肽 (48)
4.3.2美拉德反应在制备花生呈味肽中的应用 (59)
4.4 本章小结 (66)
结论与展望 (67)
一、结论 (67)
