【作者】 弓志青；

【导师】 张慜；

【作者基本信息】 江南大学 ， 食品科学， 2008， 博士

【摘要】 固体饮料营养丰富,冲饮方便,但目前固体饮料的产品大多以添加剂调配而成,以新鲜原料加工的较少。果蔬速溶固体饮料加工中普遍存在色素降解、结块等问题,本论文以新鲜杨梅和甘蓝为原料,着重研究影响喷雾干燥杨梅-甘蓝粉加工、贮藏过程中容易出现的粘壁、结块及褪色等问题,首次研究了杨梅中主要的风味物质为反-丁子香烯,占总量的60%,主要结果如下:甘蓝浆和杨梅汁流变特性研究。甘蓝浆在3 oBrix到6 oBrix范围内,流动系数n在0.22-0.33之间变化,为非牛顿流体,浓度对粘度的影响比温度的大;甘蓝浆具有一定的屈服应力,甘蓝浆表观粘度与浓度和温度的关系符合ηa=0.21exp(1.159 C+1222/T)。喷雾干燥甘蓝粉加工工艺及甘蓝中硫苷成分的分析。结果表明:加工甘蓝粉较好的喷雾干燥条件是进出口温度为185℃/80℃,均质压力为20 MPa 2次,麦芽糊精添加量占甘蓝粉总干物质含量的60%,进料浓度为5 oBrix,生产的甘蓝粉品质较好;通过液质联用在甘蓝中检测到4种硫苷组分,内叶和外叶的组分相同,喷雾干燥后硫苷保存率较高,为97.6%。速溶杨梅粉的加工及抗氧化性研究。利用响应面分析研究了喷雾干燥杨梅粉的优化工艺,结果表明:进出口温度,浓度对杨梅粉含水率有显著差异,麦芽糊精DE值的影响不显著,进口温度(140-160℃)和出口温度(65-85℃)对杨梅粉Hunter a值有显著影响,喷雾干燥杨梅粉最佳条件为进出口温度150℃/75℃,浓度12 oBrix和19 DE麦芽糊精;150-250μm之间的杨梅粉冲调性最好;杨梅粉浓度与清除自由基能力呈线性关系,1 g杨梅粉约相当于1 mgVc对自由基的清除能力,杨梅粉对不同自由基的清除能力为:DPPH·自由基>氧自由基>NO2-自由基。单粉和混合粉等温吸湿规律及显微结构分析。甘蓝粉和混合粉的等温吸湿规律呈反“S”型,喷雾干燥甘蓝粉比其它干燥方式的甘蓝粉平衡含水率低,比混合粉平衡含水率高,GAB模型可以较好地预测混合粉在不同温度下的吸附规律;混合粉中含量较高的葡萄糖和果糖是其粘壁、吸湿、结块的主要原因;杨梅粉水分活度与玻璃化转变温度呈线性关系,Tg=45.758-168.8 aw;造粒后粉内部结构疏松多孔是其冲调好的根本原因。杨梅-甘蓝粉最适加工贮藏条件的研究。混合粉加工的最适环境为温度低于25℃,相对湿度低于44%;混合粉在180天贮藏过程中,除总酚变化较大外,其余营养变化不明显,含水率为4.9%的混合粉,37℃时其半衰期为349天;含水率为7.2%的混合粉,在常温和37℃其半衰期为133和213天。杨梅-甘蓝粉冲调后色泽和风味研究。冲调混合粉温度为45℃、55℃、65℃时,花色苷降解一半所需的时间t1/2分别为173.3 min、101.9 min和50.6 min,活化能Ea为54.97 kJ/mol,Q10在1.75-1.88之间;通过HS-SPME-GC-MS对50℃和80℃冲调后杨梅粉的风味物质进行检测,风味物质有醇、烷、烯、醛、酯、酸、苯及呋喃等,杨梅中主要的风味物质是萜烯类化合物,分别占50℃和80℃风味总量的69.37%和25.59%,含量最多的萜烯是反-丁子香烯,分别占60%和22.62%,其次还有壬醛、甲氧苯基肟等。更多还原

【Abstract】 Solid beverage has rich nutrition and convenient drink, but most of solid beverage is made of additive and little is green materials. The exist problem in processing is pigment degradation and caking. We made use of fresh bayberry and cabbge and lay a strong emphasis on stickiness, caking and degradation during spray-dried bayberry-cabbage powder processing and storage. We studied that the main flavor material of bayberry was caryophyllene for the first time, which accounted for 60%. The main results were such as:Study on cabbage pulp and bayberry juice rheological properties. The cabbage pulp of flow behavior index of less than one confirmed pseudo plasticity(n =0.22-0.33). The effect of soluble solids on apparent viscosity was more pronounced than the effect of temperature. The cabbage pulp was found to behave as the yield stress. For the conditions investigated, a mathematical model,ηa=0.21exp(1.159C+1222/T), that is suitable for describing the influence of temperature and dissolved soilds on the apparent viscosity .Study on technology of spray drying cabbage powder and glucosinolate component analysis of cabbage. The optimum spray drying conditions was inlet and outlet temperature 185℃/80℃, homogenerizing pressure 20 MPa and two times, the adding amount of maltodextrin about 60%,concentration 5 oBrix, which cabbage powder had good quality. The four glucosinolate of cabbage were analyzed by high-performance liquid chromatography (HPLC), photodiode array detection (DAD), electronic spray ion mass spectrometry(ESI-MS). The inner leaf and outer leaf had the same glucosinolate components. The retention of glucosinolate was 97.6% after spray drying.RSM design of spray dried bayberry powder was studied. Inlet and outlet air temperature, bayberry juice concentration had an important effect on powder water content, but maltodextrin DE (12 and 19) value had no effect. Significant effect of the inlet, outlet air temperature on the Hunter a value of the powder was found. The optimum technology was 150℃/75℃and 12 oBrix. The higher atomizer speed, the smaller particle size of bayberry powder was. After agglomeration, the reconstitution properties of the bayberry powder was greatly improved and the particle size of good reconstitution was ranged from 150μm to 250μm. There was a linear relation between radical scavenging activity of bayberry powder and concentration. The scavenging activity of 1 g bayberry powder corresponds to activity of 1 mg vitamin C. The scavenging activity of bayberry powder was in the order of DPPH·radical> superoxide anion radical > nitric oxide radical.Sorption isotherm curves and microcosmic structure of single and mixed powder. Sorption isotherm curves of cabbage powder and bayberry powder had sigmoidal shapes typical for foods. Moisture content of cabbage powder at equilibrium was higher than the other drying cabbage powder and bayberry powder. The GAB model could well predict the isotherm of cabbage powder at each temperature. The main reason of stickiness, hygroscopic and caking is due to glucose and fructose in the cabbage powder and bayberry powder. The glass transition temperature of bayberry powder had linear relation with water activity, Tg= 45.758-168.8 aw,R2=0.8631. The main reason of good reconstitution was due to its loosen and porous structure.The appropriate processing conditions of bayberry powder should be low to 25℃and 44%RH. Apart from the total phenol, the other nutrition including water content, water activity, total sugar, reducing sugar and browning index, changed little during the 180-d storage.The color degradation and flavor changes of bayberry-cabbage powder after reconstitution was studied. The t1/2 was 349 days at 38℃w hen water content of bayberry powder was 4.9%. The t1/2 values for anthocyanin degradation were 173.3、101.9 and 50.6 min in reconstituted bayberry juice at 45℃, 55℃and 65℃, respectively. The activity energy (Ea) was 54.97 kJ/mol and Q10 was from 1.75 to 1.88. After measuring the bayberry flavor material of 50℃and 80℃reconstitution by HS-SPME-GC-MS, we found the flavor had alcohol, alkyl, alkene, aldehyde, ester, acid, benzene and furan. The main flavor was terpene, respectively 69.37% and 25.59% after 50℃and 80℃reconstitution. The most important was caryophyllene, respectively 60% and 22.62% after 50℃and 80℃reconstitution, of course nonanal and oxime-, methoxy- phenyl.更多还原