【作者】 罗凤莲；

【导师】 夏延斌；

【作者基本信息】 湖南农业大学 ， 园艺产品采后科学与技术， 2014， 博士

【摘要】 辣椒是人们日常生活中的一种重要的蔬菜和调味品。目前全球有三分之二的国家种植辣椒,我国辣椒产量居全世界之首。剁辣椒是湖南最常见的辣椒加工制品。近几年利用高盐腌制原料发展剁椒加工新技术,产品同质化现象严重,并存在严重的营养损失及环境污染。为使传统产品在工业化过程中能保持其特色,本研究以剁椒的主要生产过程为基础,以剁椒主要特征风味物质变化为着眼点,探寻辣椒在非生物因素和生物因素影响下的物理、化学变化规律,分析原料、工艺条件与剁椒品质的相关性,以期为剁椒的生产加工提供理论基础和技术指导。主要研究了常用剁椒原料(朝天椒和线椒)制作剁辣椒过程中,在不同的发酵条件下主要风味物质的变化规律,内容包括：(1)传统剁辣椒腌制过程中滋味物质的变化规律(2)不同发酵条件对剁辣椒制品有机酸种类及含量的影响(3)剁辣椒自然发酵过程中挥发性成分的变化规律(4)异常发酵对剁辣椒中滋味物质的影响(5)异常发酵对剁辣椒中挥发性成分的影响(6)超高盐腌制剁辣椒工艺与风味特点。主要结论如下：在发酵原料添加10%的食盐条件下,随发酵进程剁辣椒总糖和还原糖不断降低,总酸和氨基酸态氮含量不断升高。前期总糖、还原糖、总酸、氨基酸态氮(%)为3.62±0.06、3.25±0.07、0.26±0.01、0.048±0.004,至发酵4周时,辣椒中总糖、还原糖(%)为1.92±0.06、1.79±0.08,消耗率分别为47%、45%,总酸、氨基酸态氮(%)为0.59±0.03和0.158±0.006。剁辣椒的总糖、还原糖、脆度Fmax与鲜辣椒之间相比有极显著降低(P<0.01),总酸、氨基酸态氮则有极显著增加(P<0.01)。随食盐含量(8%-12%)增加,剁辣椒成品中的总糖、还原糖含量逐渐增加,总酸、氨基酸态氮逐渐降低,Fmax变化不显著。发酵过程中得到的剁辣椒以8%-10%食盐含量,发酵3-4周感官品质最好。在低盐条件下加工剁辣椒,加油和加糖发酵是最常用的改善风味的手段。添加食用油作为辅料制作剁辣椒,自然发酵4周后,剁辣椒检出的有机酸的含量均低于不添加食用油的剁椒有机酸,说明加油有利于控制剁椒过度发酸；而添加蔗糖发酵的剁椒检出的有机酸总量高于不加糖发酵的剁椒,并有极显著性差异(P<0.01),说明加糖有利于增强剁椒酸味；同一种辣椒原料,接种发酵与自然发酵比较,剁椒的乳酸、甲酸、乙酸、琥珀酸、有机酸总量等具有极显著差异(P<0.01)；随着发酵时间的增加,剁辣椒的有机酸种类和含量都存在一定的波动,发酵至3周时有机酸总量最高,随后略有下降。自然发酵过程中剁辣椒挥发性物质不断变化,在发酵1至4周过程中,共鉴定出125种挥发性成分,分别为103种、95种、84种、97种,共有的挥发性成分62种。先期为生青味物质多,随发酵进行,生青味类物质减少,挥发性成分总数减少,进一步发酵则产生较多的酯类、酸类物质。整体而言成品剁辣椒酯类物质的组成物数量最多,酯类物质的相对含量极显著增加(P<0.01)。主成分分析(PCA)结果表明,酯类和醛类对剁辣椒风味呈正相关作用,在添加10%的食盐条件下,发酵时间为4周时,剁辣椒的综合得分最高,与感官评价结论一致。在辣椒原料添加10%的食盐条件下,至发酵4周时,密封条件下剁辣椒的总糖、还原糖的消耗量分别为63%、62%,未密封条件下的消耗量分别为92%、91%。密封条件下剁辣椒的总酸、氨基酸态氮含量呈上升趋势,至发酵第4周分别上升到0.71%、0.15%,在未密封条件下则呈相反趋势,总酸、氨基酸态氮含量分别下降到0.15%、0.04%。密封和未密封条件下两者的总糖、还原糖、总酸、氨基酸态氮含量均有显著差异(P<0.05)。说明未密封条件会过度发酵,明显影响产品滋味；经过未密封接种发酵处理方式后,剁辣椒的挥发性成分酚类、酯类、醇类的相对含量和组成物数量显著增加,烯烃类、醛类的相对含量和组成物数量显著减少,其他物质相对含量基本不变。特别是酚类中4-乙基愈创木酚(4-EG)的相对含量均在20%以上,因其阈值极低推测对未密封接种发酵剁辣椒的酚类不良风味(POF)有较大贡献。PCA结果表明,未密封接种发酵剁辣椒中的醛类、醇类、酸类与第一主成分的相关性较大,酚类与第二主成分的相关性较大,具体为醛类、醇类呈正相关,酸类、酚类呈负相关。密封接种发酵时间过长亦会导致剁辣椒中的酯类物质总量下降,醇类物质和酚类物质增加。剁辣椒于30℃密封接种发酵1周-4周,发酵1周的剁辣椒的主成分综合得分最高,说明其风味品质最佳。接种发酵时间过长、未密封接种发酵都会使剁辣椒中的酚类物质显著增加。探索高盐盐坯剁椒的保坯条件为：在切碎的辣椒中添加质量分数23%的食盐,0.09%的柠檬酸,0.02%的焦亚硫酸钠及0.20%氯化钙能达到较好的保坯效果。脱盐后盐坯剁辣椒的总糖、总酸、还原糖、氨基酸态氮含量均有显著降低(P<0.05)。脱盐剁辣椒经过接种6%植物乳杆菌菌液,添加4%蔗糖,在30℃条件下发酵5d得到的产品最好。脱盐盐坯剁辣椒经过接种发酵后,剁辣椒的酯类、醛类物质的相对含量显著升高,醇类、烯烃类物质的相对含量显著降低,接种发酵后有助于形成剁辣椒的酯类和醛类香味。脱盐盐坯辣椒经过发酵、调味后其感官品质都有一定提高,但是仍然与传统发酵剁辣椒有一定的差距。更多还原

【Abstract】 Capsicum annuum is a kind of important vegetable and condiment in people’s daily life. Chili is grown in two-thirds of the countries around the world. The production of chili in our country is the largest in the world. Chopped chili is the most common chili products in Hunan. In recent years, chopped chili was processed with high NaCl salted chili technology. As a result, there were many similar chopped chili products and also serious nutrient loss and environmental pollution in process. In order to maintain the traditional products characteristics in industrial process, this study was based on the main production process of chopped chili. With a view to the changes of characteristic volatile components on chopped chili, the physical and chemical change rules were explored under non-biological factors and biological factors, the correlation of material, process conditions and chopped chili quality were analyzed, which would provide theoretical basis and technology guidance for chopped chili production.The study was mainly about the change rules of main volatile components of chopped chili made by Chaotian Chili and Line Chili in different fermentation conditions. The research included:(1) change rules of tasty substances of chopped chili during natural fermentation (2) change rules of types and contents of organic acids of chopped chili in different fermentation conditions (3) change rules of volatile components of chopped chili during natural fermentation (4) effect of abnormal fermentation on tasty substances of chopped chili (5) effect of abnormal fermentation on volatile components of chopped chili (6) flavor and quality characteristics of chopped chili by high NaCl salted chili. Main conclusions were as follows:Total sugar and reducing sugar content of chopped chili decreased when added 10% NaCl during fermentation, while total acid and amino acid nitrogen content of chopped chili rose. The total sugar, reducing sugar, total acid, amino acid nitrogen (%) of chopped chili before fermentation were 3.62±0.06,3.25±.07,0.26±0.01 and 0.048±0.004. Total sugar, reducing sugar(%) in chopped chili were 1.92±0.06 and 1.79±0.08 after 4 weeks fermentation, with 47% and 45% consumption rate respectively. In addition, total acid, amino acid nitrogen (%) reached 0.59±0.03 and 0.158±0.006. Total sugar, reducing sugar, hardness Fmax of chopped chili compared with fresh chili decreased extremely significantly (P< 0.01), while total acid, and amino acid nitrogen increased extremely significantly (P< 0.01). Total sugar and reducing sugar content of chopped chili increased with increasing NaCl content (8%-12%), while total acid and amino acid nitrogen content of chopped chili gradually reduced, Fmax no significant change. The sensory quality of chopped chili became better by adding 8% to10% NaCl and 3-4 weeks fermentation.In the process of low NaCl content chopped chili, oil and sugar were the most commonly means to improve flavor in fermentation. Organic acids content of chopped chili added edible oil were less than that of blank control after fermentation 4 weeks, which indicated that adding edible oil was helpful to control chopped chili too sour. However, the total organic acid of chopped chili added sugar was higher than that of blank control, which had extremely significant difference (P< 0.01) between them. That was to say, sugar was beneficial to enhance chopped chili sour. The same kind of chili material, only different from inoculation fermentation and natural fermentation, its lactic acid, formic acid, acetic acid, succinic acid and total organic acid amount of chopped chili had significant differences (P<0.01). The types and contents of organic acid of the chopped chili had some fluctuations with the increase of fermentation time. Total organic acid reached the highest content in 3 weeks then decreased a little,In the process of natural fermentation, volatile components of chopped chili changed constantly.125 volatile components were identified during 1 to 4 weeks fermentation,. There were 103,95,84 and 97 volatile components respectively and 62 volatile components. Early fermentation stage raw green flavor substances rose. Then it reduced in the process of fermentation. Later, total numbers of volatile components reduced, more esters and acids were produced during further fermentation. In a word, esters numbers were the largest and the relative content of esters increased extremely significantly (P<0.01) in chopped chili. The results of principal components analysis (PCA) indicated that esters and aldehydes had positive correlation with chopped chili flavor. With 10% NaCl content, comprehensive scores of chopped chili were the highest after 4 weeks fermentation. This result was consistent with sensory evaluation conclusion.The consumption of total sugar and reducing sugar in 10% NaCl chopped chili, reached 63% and 62% respectively after 4 weeks sealed fermentation, while it reached 92% and 91% respectively during unsealed fermentation. Total acid, amino acid nitrogen content of chopped chili rose during sealed condition, which reached 0.71% and 0.15% respectively after 4 weeks fermentation. However, the opposite trend appeared during unsealed condition, total acid and amino acid nitrogen content of chopped chili decreased to 0.15% and 0.04% respectively. Total sugar, reducing sugar, total acid and amino acid nitrogen content of chopped chili had significant difference (P<0.05) between sealed and unsealed fermentation.With unsealed inoculation fermentation treatment, relative contents and numbers of phenols, esters, alcohols increased significantly, while olefin and aldehydes decreased significantly. Other volatile compounds almost remained unchanged. The relative content of phenols especially 4-ethyl guaiacol (4-EG) were over 20% in unsealed inoculation fermentation, which might had larger contribution to phenolic off-flavor (POF) in unsealed inoculation fermentation chopped chili for its low threshold value. PCA results showed that aldehydes, alcohols and acids in unsealed inoculation fermentation chopped chili had bigger correlation with the principal component 1, while phenols had bigger correlation with the principal component 2. In particular, aldehydes and alcohols had positively correlation, acids and phenols had negatively correlation.The amount of esters of chopped chili decreased, while alcohols and phenolics increased in long time sealed inoculation fermentation. Comprehensive scores of chopped chili was the highest in sealed inoculation,30℃ for 1 week fermentation. Long time inoculation fermentation and unsealed inoculation fermentation might make phenolics in chopped chili increase significantly.The best formula for keeping high NaCl salted chopped chili quality was that 23%NaCl, 0.09% citric acid,0.02% sodium metabisulfite and 0.20% calcium chloride.Total sugar, total acid, reducing sugar and amino acid nitrogen content of desalted chopped chili reduced significantly after desalination (P<0.05). Desalted chopped chili turned to be the best quality after the treatment of 6% Lactobacillus plantarum,4% sugar,30℃ fermentation for 5 days. The relative content of esters and aldehydes of desalted chopped chili increased significantly after inoculation fermentation, while alcohols and olefins decreased significantly. Inoculation fermentation helped to improve the flavor of chopped chili. The sensory quality of desalted chopped chili through fermentation or seasoning improved slightly, but still had certain gap with the traditional fermentation chopped chili.更多还原