【作者】 黄智；

【导师】 蒋爱民；

【作者基本信息】 华南农业大学 ， 食品科学， 2018， 硕士

【摘要】 大蒜含有丰富的营养成分,具有药食两用的功能。目前,大蒜被加工成各种产品,如蒜片、蒜粒、蒜粉等。然而,在加工过程中,大蒜容易发生绿变现象,这不仅影响了产品的外观品质,还阻碍了大蒜的深加工。此外,大蒜容易发芽霉变,不耐贮藏和保存。因此,研究控制大蒜绿变的方法及其作用机理,同时开发能够长期保存的大蒜产品,为大蒜加工产业的发展提供参考和依据。本文采用烫漂的方法对大蒜进行护色,通过响应面法优化试验,确定既能够抑制大蒜绿变,又能够最大程度保留大蒜素含量的最佳护色方案。探究烫漂工艺对大蒜色泽和绿变相关酶活(γ-谷氨酰转肽酶和蒜氨酸酶)的影响,建立色泽变化及酶失活的动力学模型。同时,探究烫漂过程中大蒜素的降解规律以及大蒜抗氧化能力的变化。其次,采用最佳烫漂工艺所得蒜泥为主要原料,添加食用油、黄原胶、柠檬酸、食盐等辅料制成蒜泥产品。通过响应面法试验确定蒜泥产品的最佳配方参数。最后,建立蒜泥产品的质量分析与评价方法,对蒜泥产品的各项质量指标及流变学特性进行测定,并通过贮藏期试验确定蒜泥产品保质期。具体研究结果如下:1.护色工艺优化:通过响应面优化试验,以烫漂温度、烫漂时间、液料比为自变量,以色差a~*值和大蒜素含量为响应值,确定最佳护色工艺为:烫漂温度81℃、烫漂时间4 min,液料比10:1。2.在烫漂过程中,蒜氨酸酶和γ-谷氨酰转肽酶的失活过程都符合一级动力学模型,R~2值范围分别为0.925-0.970,0.920-0.973,二者的活化能分别为59.414、35.430 KJ/mol。一级动力学模型也能够较好地描述蒜泥绿色降解过程,R~2值范围为0.929-0.966,活化能为67.70KJ/mol。相关性分析结果显示,酶活与绿色降解成显著正相关(p<0.05),表明烫漂法通过抑制酶活达到抑制绿变的目的。3.在烫漂过程中,大蒜素降解过程可用一级动力学模型来描述,R~2值范围0.954-0.995,活化能为14.54 KJ/mol。大蒜抗氧化能力随着烫漂温度升高和烫漂时间的增加而下降。4.蒜泥产品配方优化:通过响应面优化试验,以油量、油温、黄原胶、柠檬酸为自变量,以感官评分为响应值,确定蒜泥产品的最佳配方参数为:油量16%、油温50℃、黄原胶0.6%、柠檬酸0.3%,将此配方下的蒜泥产品命名为“水性”蒜泥;在“水性”蒜泥配方的基础上通过增加油量制得“油性”蒜泥,感官评定结果显示“油性”蒜泥的最佳油量为50%。5.在感官上,“水性”蒜泥产品呈白色,具有蒜香味浓郁,无异臭味,咸辣协调,酱体细腻,粘稠适中,均匀一致。“油性”蒜泥产品中蒜泥呈白色,油呈浅黄色,蒜香味浓郁,无异臭味,口感鲜美,咸辣协调,酱体细腻,油量适中,流动性好,均匀分布。“水性”和“油性”蒜泥的大蒜素含量分别为0.73 mg/g、0.41 mg/g,菌落总数≦300cfu/g,霉菌总数≦50 cfu/g,致病菌未检出。流变学测试表明,“水性”和“油性”蒜泥均属于假塑性流体。咀嚼黏度:市售蒜泥>“水性”蒜泥>“油性”蒜泥。“水性”和“油性”蒜泥的黏度随温度升高而降低。在动态流变测定中,“水性”和“油性”蒜泥均表现出类固体的结构。6.贮藏期间蒜泥产品的品质变化及保质期的确定。在贮藏期间,蒜泥产品中玉米油的酸价和过氧化值逐渐上升,但仍符合GB 19111-2003中四级玉米油的标准;蒜泥产品的大蒜素含量不断下降,蒜味逐渐消失;总糖含量逐渐下降,5-HMF含量逐渐上升,色差b~*值逐渐增大,蒜泥产品发生褐变现象。综合感官评定结果,最终确定蒜泥产品的保质期为150天。更多还原

【Abstract】 Garlic is rich in nutrients and has both medicinal and food functions.At present,garlic is processed into garlic puree and garlic powder.However,in the process of processing,garlic is prone to greening,which not only affects the appearance quality of the product,but also hinders the further processing of garlic.In addition,garlic has a short resting period.Garlic is susceptible to mildew and cannot be stored for a long time.Therefore,it is necessary to explore methods to control the greening of garlic and its mechanism.At the same time,it is necessary to develop garlic products that can be preserved for a long time,which provides new processes and formulas for garlic processing and production,and provides reference and basis for garlic processing and production.In this paper,the method of blanching was used to protect garlic color.The parameters of blanching were optimized by response surface methodology,and the best color protection solution that can inhibit garlic greening and maximize the preservation of allicin was determined.The influences of blanching process on the activity of enzymes(γ-glutamyl transpeptidase(GGT)and alliinase)and garlic color were investigated,and dynamic models of color change and enzyme inactivation was established.At the same time,the degradation of allicin during blanching and the changes in the antioxidant capacity of garlic were investigated.Secondly,the garlic puree obtained from the best blanching process was used as main raw material,and garlic products are made by adding edible oil,xanthan gum,citric acid,salt and other auxiliary materials.The response surface method was used to optimize the optimum formulation parameters of garlic products.Finally,a quality analysis and evaluation method for garlic products was established,and a series of quality indicators and rheological properties were measured,and the shelf life of the garlic products was determined through the storage period test.The followings are results:1.The optimization of color protection process:According to response surface tests,the blanching temperature,blanching time,and liquid-to-material ratio were used as independent variables,and a*value and allicin were used as response values.The best color protection process is as follows:blanching temperature 81°C,blanching time 4 min,liquid material ratio 10:1.2.In the process of blanching,the inactivation process of alliinase andγ-glutamyl transpeptidase followed the first-order kinetics model,with R~2 values ranging from 0.925 to0.970 and 0.920 to 0.973,respectively.The activation energies of alliinase andγ-glutamyl transpeptidase were 59.414 KJ/mol and 35.430 KJ/mol,respectively.The first-order kinetic model can also describe the green degradation process of garlic,with R~2 value ranging from 0.929 to 0.966 and the activation energy is 67.70 KJ/mol.Correlation analysis showed that there was a significant positive correlation between enzyme activity and green degradation(p<0.05),indicating that blanching can inhibit greening by inhibiting enzyme activity.3.In the process of blanching,the degradation process of allicin can also be described by a first-order kinetic model,with R~2 value ranging from 0.954 to 0.995 and the activation energy is 14.54 KJ/mol.With the increase of blanching temperature and blanching time,the antioxidant capacity of garlic decreased significantly(p<0.05).4.The optimization of garlic product formula.Taking oil quantity,oil temperature,xanthan gum,and citric acid as independent variables and sensory evaluation scores as response values,the optimum formulation parameters of garlic products were optimized by response surface methodology:oil content 16%,oil temperature 50℃,xanthan gum 0.6%,citric acid 0.3%.The garlic product under this formula was named"aqueous"garlic puree;on the basis of"aqueous"garlic formula,the amount of oil was increased to 50%to obtain"oily"garlic puree.5.In the senses,"aqueous"garlic products are white,with a strong garlic flavor,coordinated salty and spicy,delicate the sauce body,moderate stickiness;"oily"garlic products are white,the oil is light yellow,with a strong garlic flavor,coordinated salty and spicy,delicate the sauce body,good fluidity and even distribution.The allicin contents of“aqueous”and“oily”garlic were 0.73 mg/g,0.41 mg/g.The total number of colonies was≦300 cfu/g,and the total number of moulds was≦50 cfu/g,and there was none of pathogenic bacteria.Rheological tests have shown that both"aqueous"and"oily"garlic mud are pseudoplastic fluids.The order of chew viscosity is:commercial garlic>"aqueous"garlic>"oily"garlic.In dynamic rheological measurements,both"aqueous"and"oily"garlic puree exhibited a solid-like structure.6.The quality change of the garlic product during storage and the determination of the shelf life.With the prolongation of storage time,the acid value and peroxide value both increased.During the storage,the acid value and peroxide value of corn oil in the product were in line with the standard of the fourth grade corn oil in GB 19111-2003;The allicin content of two kinds of garlic products continued to decline,and the garlic taste gradually disappeared;the total sugar content gradually decreased,the 5-HMF content gradually increased,and the garlic products gradually browned.It was finally determined that the shelf life of garlic products was 150d.更多还原