黑蒜低聚糖的产生规律及功能作用研究
发布时间：2019-07-04 19:09
【摘要】：黑蒜是新鲜大蒜通过控制温度和湿度加工一段时间后形成的大蒜深加工产品。经过加工后蒜瓣由白色变为黑褐色,柔软并富有弹性,去除了大蒜的辛辣味并增强了其生理活性。黑蒜起源于日本,其加工技术也来源于日本,需要发酵60~90天,工艺时间长,产品能耗高。目前,黑蒜生产工艺常采用变温发酵方式,可以缩短加工时间,提高黑蒜产品的品质,节约能源。但由于工艺不同,造成不同黑蒜的含水量、还原糖等成分不同。大蒜中具有生理功能的成分主要是含硫化合物和多糖,其中多糖约占大蒜干重的75%以上。目前,对大蒜的研究主要集中在大蒜素、大蒜油等成分上,并取得了大量的研究成果。但对大蒜多糖的研究相对较少。新鲜大蒜中的糖主要为多糖,食用无甜的口感,经过加工后黑蒜中低聚糖、还原糖含量明显升高,赋予黑蒜甜味,这些糖的产生途径未知,且食用加工后的黑蒜是否对便秘及肠道菌群产生影响鲜有报道。因此本研究比较了大蒜与黑蒜中成分差异,提取大蒜中性多糖并分析其结构,研究其酸水解规律及产物益生活性,并对黑蒜加工过程中多糖降解途径进行探究,采用动物实验的方式研究黑蒜对小鼠的润肠通便功能及肠道菌群的影响,为进一步揭示黑蒜品质形成机理,提高黑蒜品质,开发黑蒜功能具有十分重要的科学意义。主要研究结果如下:1.大蒜加工成黑蒜后营养成分发生了显著变化。与大蒜相比,黑蒜中的含水量、脂肪等成分下降,有机酸、总酚、5-HMF含量显著升高,特别是还原糖含量由0.46 g/100g升高至39.49 g/100g,升高了上百倍。而对18种游离氨基酸测定发现部分游离氨基酸含量下降,氨基酸总含量下降。2.大蒜粗多糖经DEAE-52纤维柱纯化后采用红外光谱(FITR)分析、凝胶排阻色谱(GPC)分析其分子量、高效液相色谱(HPLC)分析其单糖组成发现大蒜中性多糖是具有不同聚合度的分散性多糖,其平均分子量为6569 Da,单糖组成为葡萄糖和果糖,摩尔质量比为4:1。酸水解实验发现,底物浓度越低、pH越低、温度越高,大蒜中性多糖水解速率越快。大蒜中性多糖水解动力学结果研究发现其未调节pH和pH=3的水解前期,大蒜中性多糖的水解遵循一级反应。3.大蒜中性多糖经过酸水解、超滤后获得大蒜低聚糖。经过水解后的分子量明显下降,低聚糖含量明显升高,聚合度(DP)10的低聚糖含量由15%以下升高至75%以上。其中单糖含量在0.5%以下,低聚糖的平均分子量为1444 Da,平均聚合度约为8。与大蒜中性多糖相比,水解后的低聚糖抗人造胃液水解能力略低,但其能显著促进四种乳酸菌的增殖,降低发酵液pH,具有更强的益生活性。4.通过单因素试验及正交试验确定黑蒜多糖的提取工艺为料水比1:12,提取温度70℃,提取时间60 min。对大蒜和黑蒜中多糖分子量分布分析发现鲜蒜中的分子量范围主要在1~15 kDa之间,其中平均分子量4 kDa以上的糖类约占总量的80%以上。而经过加工以后,黑蒜中的糖类平均分子量均为2 kDa以下,其中1 kDa以下糖类约占90%以上。5.对黑蒜加工过程中多糖降解规律研究发现:在黑蒜加工过程中多糖的降解大部分以高温降解为主,几乎没有果聚糖酶的参与。多糖的分子量越来越小,且温度越高,多糖降解越剧烈。对其动力学分析发现70~80℃下呈线性降解,85~90℃下曲线偏离线性关系,对其活化能计算得活化能为110.56 kJ·mol~(-1),前指因子A为3.12×10~(12) h~(-1)。6.动物实验结果显示黑蒜不会对小鼠的血液指标造成不良的影响。黑蒜对便秘模型小鼠具有良好的润肠通便作用,能明显提高便秘模型小鼠的小肠内容物推进率、缩短首次排黑便时间、增加6 h内排黑便粒数、重量及提高粪便含水量效果。黑蒜能够改变肠道菌群结构,增加肠道菌群的丰度。在门水平上,黑蒜增加拟杆菌门、变形菌门比例,降低厚壁菌门比例,呈现偏向以拟杆菌门为主。在属水平上对应的拟杆菌属、拟普雷沃菌属、阿克曼氏菌属比例升高,乳酸菌属、梭菌属比例下降。黑蒜能够促进丁酸含量显著性增加,但不引起小鼠粪便中总短链脂肪酸含量的升高。
文内图片：
图片说明：低聚果糖的分子结构
[Abstract]:The black garlic is the garlic deep-processing product formed after the fresh garlic is processed for a period of time by controlling the temperature and the humidity. After being processed, the garlic cloves are changed from white to black-brown, soft and elastic, and the pungent taste of the garlic is removed and the physiological activity of the garlic is enhanced. The black garlic originates from Japan, and its processing technology is also from Japan. It needs to be fermented for 60-90 days, the process time is long, and the energy consumption of the product is high. At present, the production process of the black garlic often adopts a temperature-changing fermentation mode, so that the processing time can be shortened, the quality of the black garlic product can be improved, and the energy can be saved. However, due to the different process, the water content, reducing sugar and other components of different black garlic are different. The essential components of the garlic are sulfur-containing compounds and polysaccharides, wherein the polysaccharide accounts for more than 75% of the dry weight of the garlic. At present, the research on garlic is mainly concentrated on the components of garlicin and garlic oil, and a lot of research results have been obtained. However, the research of the garlic polysaccharide is relatively low. The sugar in the fresh garlic is mainly the polysaccharide, and the sweet taste is consumed. After the processing, the sugar content of the oligosaccharide and the reducing sugar in the black garlic is obviously increased, the sweet taste of the black garlic is given, the production route of the sugar is unknown, and whether the black garlic after the edible processing has little influence on the constipation and the intestinal flora is rarely reported. In this study, the composition of garlic and black garlic was compared, the neutral polysaccharide of garlic was extracted and its structure was analyzed, the acid hydrolysis and product benefit of the garlic were studied, and the way of polysaccharide degradation during the processing of black garlic was studied. The effects of black garlic on the function of relaxing bowel and the intestinal flora in mice were studied by animal experiment. It is of great scientific significance to further reveal the formation mechanism of black garlic, improve the quality of black garlic and develop the function of black garlic. The main results are as follows:1. The nutritional components of garlic processed into black garlic have changed significantly. Compared with the garlic, the water content, fat and other components in the black garlic are reduced, and the content of the organic acid, the total phenol and the 5-HMF is increased obviously, in particular, the content of the reducing sugar is increased from 0.46 g/ 100g to 39.49 g/ 100g, and the content of the reducing sugar is increased by 100 times. The results showed that the content of free amino acids decreased and the total content of amino acids decreased in 18 free amino acids. The crude polysaccharide of garlic was purified by DEAE-52 fiber column. The molecular weight and high performance liquid chromatography (HPLC) of the crude polysaccharide of garlic were analyzed by means of infrared spectroscopy (FITR), and its molecular weight and high performance liquid chromatography (HPLC) were used to analyze its monosaccharide composition. It was found that the garlic-neutral polysaccharide was a dispersible polysaccharide with different degree of polymerization, with an average molecular weight of 6569 Da, The monosaccharide composition is glucose and fructose, and the molar mass ratio is 4:1. The acid hydrolysis experiments show that the lower the substrate concentration, the lower the pH, the higher the temperature, and the faster the hydrolysis rate of the garlic neutral polysaccharide. The results of the hydrolysis of the neutral polysaccharide of garlic found that the hydrolysis of the neutral polysaccharide of the garlic was followed by the first-order reaction in the pre-hydrolysis of the unadjusted pH and pH = 3. The garlic neutral polysaccharide is subjected to acid hydrolysis and ultrafiltration to obtain the garlic oligosaccharide. The molecular weight after hydrolysis is obviously reduced, the content of the oligosaccharide is obviously increased, and the oligosaccharide content of the degree of polymerization (DP)10 is increased from below 15% to more than 75%. Wherein the content of the monosaccharide is below 0.5%, the average molecular weight of the oligosaccharide is 1444 Da, and the average degree of polymerization is about 8. Compared with the garlic neutral polysaccharide, the hydrolysis ability of the hydrolyzed oligosaccharide is slightly lower than that of the artificial gastric juice, but can obviously promote the proliferation of the four kinds of lactic acid bacteria, reduce the pH of the fermentation liquid and have a stronger beneficial life. The extraction process of the black garlic polysaccharide was determined by single factor test and orthogonal test as the ratio of water to water of 1:12, the extraction temperature was 70 鈩，
本文编号：2510152
文内图片：
图片说明：低聚果糖的分子结构
[Abstract]:The black garlic is the garlic deep-processing product formed after the fresh garlic is processed for a period of time by controlling the temperature and the humidity. After being processed, the garlic cloves are changed from white to black-brown, soft and elastic, and the pungent taste of the garlic is removed and the physiological activity of the garlic is enhanced. The black garlic originates from Japan, and its processing technology is also from Japan. It needs to be fermented for 60-90 days, the process time is long, and the energy consumption of the product is high. At present, the production process of the black garlic often adopts a temperature-changing fermentation mode, so that the processing time can be shortened, the quality of the black garlic product can be improved, and the energy can be saved. However, due to the different process, the water content, reducing sugar and other components of different black garlic are different. The essential components of the garlic are sulfur-containing compounds and polysaccharides, wherein the polysaccharide accounts for more than 75% of the dry weight of the garlic. At present, the research on garlic is mainly concentrated on the components of garlicin and garlic oil, and a lot of research results have been obtained. However, the research of the garlic polysaccharide is relatively low. The sugar in the fresh garlic is mainly the polysaccharide, and the sweet taste is consumed. After the processing, the sugar content of the oligosaccharide and the reducing sugar in the black garlic is obviously increased, the sweet taste of the black garlic is given, the production route of the sugar is unknown, and whether the black garlic after the edible processing has little influence on the constipation and the intestinal flora is rarely reported. In this study, the composition of garlic and black garlic was compared, the neutral polysaccharide of garlic was extracted and its structure was analyzed, the acid hydrolysis and product benefit of the garlic were studied, and the way of polysaccharide degradation during the processing of black garlic was studied. The effects of black garlic on the function of relaxing bowel and the intestinal flora in mice were studied by animal experiment. It is of great scientific significance to further reveal the formation mechanism of black garlic, improve the quality of black garlic and develop the function of black garlic. The main results are as follows:1. The nutritional components of garlic processed into black garlic have changed significantly. Compared with the garlic, the water content, fat and other components in the black garlic are reduced, and the content of the organic acid, the total phenol and the 5-HMF is increased obviously, in particular, the content of the reducing sugar is increased from 0.46 g/ 100g to 39.49 g/ 100g, and the content of the reducing sugar is increased by 100 times. The results showed that the content of free amino acids decreased and the total content of amino acids decreased in 18 free amino acids. The crude polysaccharide of garlic was purified by DEAE-52 fiber column. The molecular weight and high performance liquid chromatography (HPLC) of the crude polysaccharide of garlic were analyzed by means of infrared spectroscopy (FITR), and its molecular weight and high performance liquid chromatography (HPLC) were used to analyze its monosaccharide composition. It was found that the garlic-neutral polysaccharide was a dispersible polysaccharide with different degree of polymerization, with an average molecular weight of 6569 Da, The monosaccharide composition is glucose and fructose, and the molar mass ratio is 4:1. The acid hydrolysis experiments show that the lower the substrate concentration, the lower the pH, the higher the temperature, and the faster the hydrolysis rate of the garlic neutral polysaccharide. The results of the hydrolysis of the neutral polysaccharide of garlic found that the hydrolysis of the neutral polysaccharide of the garlic was followed by the first-order reaction in the pre-hydrolysis of the unadjusted pH and pH = 3. The garlic neutral polysaccharide is subjected to acid hydrolysis and ultrafiltration to obtain the garlic oligosaccharide. The molecular weight after hydrolysis is obviously reduced, the content of the oligosaccharide is obviously increased, and the oligosaccharide content of the degree of polymerization (DP)10 is increased from below 15% to more than 75%. Wherein the content of the monosaccharide is below 0.5%, the average molecular weight of the oligosaccharide is 1444 Da, and the average degree of polymerization is about 8. Compared with the garlic neutral polysaccharide, the hydrolysis ability of the hydrolyzed oligosaccharide is slightly lower than that of the artificial gastric juice, but can obviously promote the proliferation of the four kinds of lactic acid bacteria, reduce the pH of the fermentation liquid and have a stronger beneficial life. The extraction process of the black garlic polysaccharide was determined by single factor test and orthogonal test as the ratio of water to water of 1:12, the extraction temperature was 70 鈩，
本文编号：2510152
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