鲜茶汁浸提工艺研究

研究鲜茶固体饮料加工的鲜茶汁制备提取工艺,以鲜茶汁浸提温度、时间及茶水比为影响因素,采用正交试验设计L9（3）^3,探讨浸提工艺对鲜茶汁的感官品质、提取得率、浓度、主要生化成分浸出量、酚氨比、外观颜色及冷后浑等的影响。结果表明,随着浸提温度的升高和时间的增加,鲜茶汁的感官品质下降,但鲜茶汁提取率、浓度增大,茶水比1：1（W／V）时鲜茶汁提取率和浓度较高且感官品质较好。综合考虑鲜茶汁的感官风味品质、提取得率及产业化成本,鲜茶汁提取最佳工艺参数为浸提温度45℃,浸提时间10min,茶水比1：10（W／V）。     

不同品种莲藕加工制汁适宜性评价

为探究不同品种莲藕加工制汁的适宜性,选用了10个具有代表性的莲藕品种为实验材料,测定了莲藕原料的理化指标和基本营养成分,并对制得的莲藕鲜榨汁的加工品质、营养价值及物理性质进行分析,结合主成分分析和聚类分析方法对莲藕鲜榨汁品质进行综合评价。结果表明:10种莲藕原料及其鲜榨汁的各项品质指标均存在显著性差异(P＜0.05),通过主成分分析将莲藕鲜榨汁9个品质指标降维为3个因子,累计贡献率达88.279%。聚类分析将10种莲藕划分为4类,第Ⅰ类为鄂莲5号、鄂莲6号和鄂莲11号;第Ⅱ类为庐江花香藕、浠水巴河莲藕、鄂莲9号、杭州白莲藕和新35;第Ⅲ类为武植二号;第Ⅳ类为沔城藕。进一步对莲藕鲜榨汁品质指标与莲藕原料品质指标的相关性分析发现,藕肉亮度小、淀粉含量低和出汁率高的品种更适合加工制汁。因此,杭州白莲藕、浠水巴河莲藕、鄂莲9号和庐江花香藕更适合作为制汁专用品种。     

百香果鲜榨汁对6种食源性致病菌的抑菌效果及被膜形成的影响

分别研究百香果鲜榨果肉汁和果皮汁对6种常见食源性病原菌的抑菌效果以及对细菌生物被膜形成的影响。采用平板抑菌试验研究鲜榨汁抑菌效果,并探究浓度和加热时间对果肉汁抑菌效果的影响;采用96孔板法研究两种鲜榨汁对细菌被膜形成影响;采用酸碱滴定法测定两种鲜榨汁总酸度;用气相色谱-质谱联用技术(GC-MS)分析两种鲜榨汁的挥发性成分。研究结果表明:果肉鲜榨汁对6种常见食源性致病菌有明显的抑菌效果,而果皮鲜榨汁未出现抑菌作用;随着果肉汁浓度减少,其抑菌效果也变弱;加热时间对果肉汁的抑菌效果影响不明显,说明果汁中抑菌成分的热稳定性较好。另外,果肉鲜榨汁对细菌被膜形成有抑制作用,果皮鲜榨汁对细菌被膜形成具有很好的促进作用。进一步分析发现果肉鲜榨汁总酸为3.185 g/100 m L,果皮鲜榨汁总酸为0.0904 g/100 mL,提示酸度对抑菌起主要作用。GC-MS结果表明果皮汁中的主要挥发性成分以醛类、醇类、酯类、烷烃类和酮类物质等为主,果肉汁中的主要挥发性成分以酯类、醇类和酮类等物质为主。本研究结果为百香果的利用开发提供基础数据。     

采用星点设计-效应面优化五汁饮的制备工艺

为优化五汁饮的制备工艺,以感官评定为指标,在单因素试验基础上采用星点设计-效应面优化法(CCDRSM)优化最佳配比工艺。同时在配比工艺基础上,以透光度为指标,考察果胶酶添加量、酶解时间和酶解温度对五汁饮澄清效果的影响。结果表明:得到的最佳配比工艺为:鲜藕20 g、鲜荸荠30 g、鲜麦冬5 g、鲜梨70 g、鲜芦根8 g。最佳澄清工艺为:果胶酶添加量0.20%,酶解时间150 min,酶解温度55℃。优选的制备工艺稳定、可行,为五汁饮的进一步开发奠定基础。     

超高压联合酶解处理对红枣汁品质的影响

采用了5种不同强度的压强，分别基于超高压再酶解、酶解再超高压及仅酶解进行了红枣汁的制备，结合电子舌、电子鼻和色度仪等仿生设备和多元统计学等方法，对制备的33个红枣汁样本的感官品质进行评价。并通过主成分分析、典范对应分析、聚类分析、冗余分析和多元方差分析等手段进行差异分析。结果表明，超高压再酶解和酶解再超高压对红枣汁的品质影响大于压强，经超高压处理后的红枣汁整体品质较为接近，且两组与仅酶解之间的感官品质存在极显著差异（P<0.001）。冗余分析证明该差异主要是由芳香类物质、烷烃类物质和硫化物等风味指标造成的，且以酶解后超高压制备的红枣汁品质为更佳，同时研究发现超高压处理有助于提升红枣汁的非生物稳定性。由此可见，超高压处理能明显改善红枣汁的品质。     

枸杞叶茶保健酒的研究

研究了枸杞叶茶保健酒酿制工艺,对茶汁的提取和发酵阶段的工艺参数进行优化.通过实验确定最佳工艺参数:茶汁与枸杞汁比例7:3;调整发酵醪液pH值为5.5;酵母菌为EC118,酵母活化后添加;发酵温度控制在24℃±2℃;澄清剂为明胶0.1 g/L、皂土1.5 g/L,进行混合澄清处理;成品枸杞叶荼保健酒感官品质最佳.     

微生物发酵法制备鲜辣沙蟹汁工艺研究

为了提升鲜辣沙蟹汁的品质,改良制备工艺.文章选择植物乳杆菌(Lactobacillus plantarum)和鲁氏酵母菌(Saccharomyces rouxii)作为发酵菌种,以感官评价和氨基酸态氮含量为指标,通过单因素实验结合正交实验优化最佳工艺条件及配方.研究结果表明,发酵时间为18 d,发酵温度为29℃,沙蟹添...     

基于电子鼻评价不同贮藏期蜜桔鲜榨汁品质的研究

为建立一种快速无损检测蜜桔鲜榨汁品质的方法,将宫川蜜桔(satsuma mandarins)置于20℃、相对湿度85%条件下贮藏,每3 d随机选取10个果实制成汁,利用PEN3电子鼻检测其香气,同时测定其主要品质指标并进行相关性分析。通过主成分分析(Principal Component Analysis,PCA)、线性判别分析(Linear Discriminant Analysis,LDA)对不同贮藏时间的蜜桔进行区分。结果显示:电子鼻传感器响应值与蜜桔鲜榨汁可溶性固形物含量和VC含量显著相关;线性判别分析能较好地区分出不同贮藏时间的蜜桔;负荷加载分析(Loading analysis)结果显示,传感器W1S(主要对甲烷灵敏)、W2S(对乙醇灵敏,也对部分芳香型化合物灵敏)和W2W(对芳香成分和有机硫化物灵敏)在蜜桔鲜榨汁品质评价中起主要作用。结果表明利用电子鼻技术有望实现对蜜桔鲜榨汁品质的快速无损检测。     

甘蔗渣制茶工艺优化

本研究利用甘蔗榨汁后的甘蔗渣制作甘蔗茶,通过二次回归正交旋转组合试验探讨了炒制温度、炒制时间和转速对甘蔗茶感官评分的影响,确定最优制作工艺条件,并测定最优制备工艺下甘蔗茶营养成分含量。结果表明,炒制温度为127 ℃,炒制时间33 min,转速为60 r/min时,在此条件下,甘蔗渣制茶工艺最优,感官评分为92.47分,感官评价良好,此时甘蔗茶营养成分含量分别为:脂肪0.25%±0.06%,蛋白质1.99%±0.39%,还原糖7.26%±0.38%,水分6.48%±0.27%,灰分1.89%±0.20%,该研究可为甘蔗渣利用提供参考。     

响应面法优化草莓鲜榨汁紫外杀菌工艺

以草莓鲜榨汁为原材料,进行紫外线杀菌,研究草莓鲜榨汁厚度、紫外线照射距离和紫外线照射时间对菌落总数、霉菌和酵母菌总数杀菌率的影响。利用响应面分析法确定紫外线杀菌的最佳工艺参数为果汁厚度0.7?mm、照射距离8.0?cm、照射时间62?min,得到实际杀菌率为99.24%。在最佳工艺条件下对草莓鲜榨汁进行紫外杀菌,并与巴氏杀菌比较对草莓鲜榨汁品质指标的影响。结果表明：紫外线杀菌可以提高草莓鲜榨汁中花色苷和总酚的含量;有利于减缓草莓鲜榨汁中可滴定酸含量的降低,但对可溶性固形物无显著影响;另外紫外线杀菌降低了草莓鲜榨汁中VC的含量,但是与巴氏杀菌相比较,VC损失率减少了28.7%。这说明紫外线杀菌可以在达到商业无菌的前提下,维持草莓鲜榨汁中的营养成分。     

揉捻和干燥方法对柿叶茶品质的影响

研究了揉捻和不同干燥方法对安溪油柿叶茶品质的影响。结果表明:揉捻可增加柿叶茶的细胞破损率,从而使柿叶茶的水浸出物含量增加,有利于提高柿叶茶的可冲泡性。柿叶茶采用炒干能够得到较适宜的营养成分含量,而且经过炒干的柿叶茶色泽黄绿、香气浓厚、滋味鲜醇回甘、叶底绿匀,感官评分高。柿叶茶炒干时要注意控制火候和时间,而且在炒制过程中还要经常翻动。     

杀青工艺对柿叶绿茶感官品质的影响

以不同的杀青方式,探讨杀青工艺对柿叶绿茶感官品质的影响。结果表明:柿叶绿茶以鲜叶直接采用锅式炒青的感官品质最佳;杀青条件以150℃、3min的处理形成的柿叶绿茶感官品质最好。     

蓝莓红巧梅花茶饮料加工工艺的研究

用果胶酶制备鲜蓝莓汁,反应温度为50℃、加酶量0.5%、酶解4h。制备红巧梅花茶的浸渍温度为80℃、加水量50mL、浸渍时间为60min。复合原汁最佳配比为鲜蓝莓汁:红巧梅花茶汁=2:3(体积比)混合,确定风味调配加工工艺为复合原汁含量20%、蜂蜜添加8%、VC添加0.3%。蓝莓红巧梅花茶饮料色泽、口感、风味俱佳,且营养丰富,适合大众口味。     

UHT杀菌对绿茶饮料风味的影响研究

研究了UHT杀菌对绿茶饮料风味的影响，通过绿茶饮料在UHT杀菌前、后香气成分的定性．定量分析，说明UHT杀菌在杀死绿茶饮料中的有害及腐败微生物时．不仅可以极大程度地保留产品中的营养成分和风味成分，同时还增加了绿茶饮料的甜香成分．     

杏汁饮料的工艺配方及稳定性研究

以新鲜杏肉为主要原料设计了混浊型果汁饮料的加工工艺,采用正交实验设计方案,以感官风味作为评价指标,优选出杏汁、蔗糖和柠檬酸的最佳复配比为：14％杏汁＋8％蔗糖＋0．08％柠檬酸,并确定复合稳定剂的最佳组合为：0．10％果胶＋0．15％CMC＋0．10％黄原胶。     

Evaluation of microbial inactivation and physicochemical properties of pressurized tomato juice during refrigerated storage

Effects of high pressure processing (300-500 MPa/25 °C/10 min) on microbial inactivation and processing qualities of tomato juices during refrigerated storage at 4 °C for 28 days were investigated to compare with those of conventionally thermal processing. Conventionally, thermal processing almost inactivated all the microorganisms and pectolytic enzymes and produced microbially and consistency stable tomato juices; however, they also reduced the color, extractable carotenoids and lycopene and vitamin C compared with fresh juice. During storage, all the pressure processing could improve the extractable carotenoids and lycopene contents compared with fresh juice, and they also retained more vitamin C contents than thermal processing. Although 300- and 400-MPa processing could retain a/b values of tomato juices as fresh juice during storage for 21 and 28 days, 500-MPa processing could improve the color of juices even after storage. Syneresis occurred in the 300- and 400-MPa processing juices by storing for 7 and 14 days; however, viscosity stable juice was produced by 500-MPa processing. Moreover, 400- and 500-MPa processing significantly inactivated microorganisms and the juices were microbially stable during storage. This study demonstrated that 500-MPa processing would be an alternative for conventionally thermal processing for tomato juice with improvement of some processing quality attributes.     

Novel,non-thermal hydrodynamic cavitation of orange juice: Effects on physical properties and stability of bioactive compounds

Effect of hydrodynamic cavitation (HC) at pressure 3–15 bar and treatment time5–25 min on physical and chemical qualities of orange juice was investigated. Processing parameters were optimized on the basis of retention of vitamin C and antioxidant activity; inactivation of pectin methyl esterases (PME) and peroxidase (POD) enzyme and stability of pH, °Brix, viscosity, titratable acidity and total color difference. HC of orange juice at 5 bar 15 min and 13 bar 10 min resulted into maximal overall desirability at 0.52 and 0.40 respectively. No significant change in °Brix, pH, titratable acidity for fresh and cavitated orange juice was observed. Only 21% and 13% of reduction in PME and POD respectively was recorded. A 94% and 91% of antioxidant activity and vitamin C retention was noted in both optimized samples. This study demonstrated that HC can produce orange juice more economically with better physical properties and nutritional value.Industrial relevanceThe demand for more natural, preservative free with highest nutritional bioactive containing juices has created a need of non-thermal processing. Hydrodynamic cavitation (HC) processing is novel, emerging and under explored technology for fruit juices. HC due to the formation of cavities and shock waves causes enzyme and microbial inactivation at low temperature while retaining natural bioactives with fresh-like organoleptic characteristics. It is believed worldwide that non thermal technologies like HC will be among the most cost effective, scalable and impactful liquid food processing technologies in the coming decades especially for commercial products.     

高压脉冲电场和热处理对蓝莓汁品质的影响

以蓝莓汁为原料,比较了高压脉冲电场（PEF）杀菌和热力杀菌处理对蓝莓汁中微生物和理化指标的影响,以及不同处理的蓝莓汁在贮藏期间的品质变化规律。结果表明：PEF可以有效杀灭蓝莓汁中的微生物;PEF杀菌对蓝莓汁色泽参数影响程度小;杀菌处理后,贮藏期内PEF处理和热处理对蓝莓汁的还原糖、总酸、可溶性固形物含量、总酚含量影响较小,PEF处理较热处理能更好地保持蓝莓汁中的VC和花青素含量。     

芹菜汁绿茶复合饮料的研制

以芹菜、绿茶为主要原料,研究了复合饮料的加工工艺。通过正交试验和感官评定,确定了复合饮料的最佳配方。综合比较了澄清型和混浊型复合饮料的感官及理化指标,如透光率、pH值、可溶性固形物含量、总黄酮含量和茶多酚含量等,结果表明澄清型复合饮料色泽鲜亮,口感清爽,且功能性成分含量较丰富。     

Changes in total phenolic and flavonoid content and antioxidative activities during production of juice concentrate from Asian pears (Pyrus pyrifolia Nakai)

The total phenolic and flavonoid content and antioxidative activities during production of pear juice concentrate (PJC) from two cultivars, Hwasan and Niitaka, were investigated. The main processing steps in PJC production are washing, pressing, pasteurization, clarification, filtration, evaporation, and packaging. Total phenolic and flavonoid content of end-product PJC from Niitaka decreased by 53.11 and 46.47%, respectively, while those from Hwasan decreased by 55.46 and 36.09%, respectively, compared to the phenolic and flavonoid content of original fresh fruit. DPPH radical-scavenging activities, reducing power and nitrate radical-scavenging activities showed a similar tendency as total phenolic and flavonoid content; that is, they decreased in juice concentrate made from both cultivars. Also, antioxidant activities of press cake waste (skin and seeds) from Niitaka and Hwasan pears were higher than fresh pears. In conclusion, antioxidant levels were significantly affected during processing of PJC, especially during the pressing step in which press cake waste retains the seeds and skin.