【作者】 王海翔；

【导师】 潘见；

【作者基本信息】 合肥工业大学 ， 农产品加工及贮藏工程， 2009， 博士

【摘要】 橙汁由于其营养丰富而深受消费者青睐,但目前的热杀菌工艺严重破坏橙汁的天然风味。超高压技术是最有希望代替热杀菌而应用于果汁行业。作者单位成功开发了超高压鲜橙汁,产品最大限度地保持了原汁的天然风味。但在研究开发过程中发现,橙汁经高压处理后会产生一种微弱异味。为进一步提高鲜榨汁品质,本文对异味产生的原因及物质基础,异味形成的机理及相关影响因素,抑制异味产生的措施进行了探讨,主要研究结论如下:1.鲜榨橙汁超高压加工过程中产生异味是由于α-松油醇和香芹酮的生成所致。新增α-松油醇是由柠檬烯的水合反应和芳樟醇的降解而共同累积,香芹酮则由柠檬烯在高压下发生氧化反应生成。2.压力x1、温度x2、时间x3三因素显著影响着柠檬烯和芳樟醇在高压下的反应,并且三因素的增加对降解起正效应作用。芳樟醇Y1、柠檬烯Y2与三因素的关系可用回归方程表示如下:3.金属离子能催化高压下柠檬烯的氧化反应,显著加快柠檬烯的降解(P<0.05);对柠檬烯的水合反应和芳樟醇的降解不起显著作用(P>0.05)。4. pH2.8～5.2之间,pH值增加对柠檬烯的降解起负效应,pH5.2～6.0之间,pH值增加对柠檬烯的降解起正效应;pH2.8～6.0之间,pH值增加对芳樟醇的降解起负效应。芳樟醇Y1、柠檬烯Y2同压力x1和pH值x4的关系可用回归方程表示如下5.鲜榨汁中添加0.15‰(w/v)的柠檬烯再高压处理,成品中的柠檬烯气味可以有效掩盖异味。6.真空脱气(真空度0.095 MPa,3 min)可显著的降低柠檬烯的氧化反应速度,对柠檬烯的水合反应和芳樟醇的降解没有显著作用。7.添加蛋白质可以螯合橙汁中的金属离子,对柠檬烯在高压下的氧化反应有显著影响,可以抑制柠檬烯在高压下的降解;但添加蛋白对柠檬烯的水合反应和芳樟醇的降解没有显著作用,最适合的添加浓度为30μg/mL。更多还原

【Abstract】 Orange juice is favored by consumers because of its nutrient-rich. At present, the thermal sterilization process seriously damage the natural flavor of orange juice. Ultra-high pressure technology is the most promising substitute for heat sterilization in juice industry. Our laboratory successfully developed the orange juice product by ultra-high pressure to maximize the juice to keep the natural flavor. However, orange juice will produce a slight off-flavor after high pressure treatment. In order to further improve the smell quality of fresh juice, this paper was focused on the causes and the formation mechanism of off-flavor. Based on these studies, the ways how to reduce the production of off-flavour were also found. Main research finding was following:1. Fresh orange juice processed by ultra-high pressure could produce a slight off-flavor as a result of the productions ofα-terpineol and carvone.α-terpineol was created by hydration reaction of limonene and linalool degradation, while carvone was created by oxidation reaction of limonene.2. Pressure (x1), temperature (x2), treatment time (x3) were three significant factors influencing the degradations of limonene and linalool under high pressure and there were positive effect on degradation with increasing of three factors. The relationship of linalool (Y1) or limonene (Y2) concentrations between three factors could be expressed by the regression equation as follows:3. Metal ions as a catalyzer influencing oxidation of limonene under high pressure, could significantly speed up the degradation of limonene; while it did not play an important role on the hydration of limonene and degradation of linalool.4. At pH2.8 ~ 5.2, there was a negative effect on limonene degradation with increasing of pH values; at pH5.2 ~ 6.0, there was a positive effect on limonene degradation with increasing of pH values; at pH2.8 ~ 6.0 between, there was a negative effect on linalool degradation with increasing of pH values. The relationship of linalool (Y1) or limonene (Y2) concentrations between the pressure (x1) and pH values (x4) could be expressed by the regression equation as follows:5. When some limonene (0.15‰, w/v) was added to orange juice before ultra-high pressure processing, the smell quality of treated-juice could effectively improved.6. Vacuum degassing (vacuum degree of 0.095 MPa, 3 min) could significantly reduce the the reaction of limonene oxidation while it did not play an important role on the hydration of limonene and degradation of linalool.7. protein which could chelated metal ions in orange juice have a significant impact on the oxidation reaction, resulting in a significant reduction of limonene degradation under high pressure, while there was no significant effect on the hydration of limonene and degradation of linalool. Protein was added to orange juice with a concentration of 30μg/mL.更多还原