酵素中具有抑菌能力乳酸菌的筛选及鉴定

该研究探讨了从酵素中分离纯化具有抗菌性能的12株乳酸菌,对其进行生理生化实验和API鉴定。利用牛津杯法对阪崎大肠杆菌、鼠伤寒沙门氏菌和宋内志贺氏菌、大肠杆菌、金黄色葡萄球菌进行抑菌特性研究,并探讨了乳酸菌是否产生物胺能力和偶氮还原酶。结果表明,酵素源的12株乳酸菌对肠道致病菌均具有不同程度的抑菌活性,其抑菌圈直径为14~22 mm,对大肠杆菌的抑菌效果较好,其抑菌圈直径为15~23 mm,对金黄色葡萄球菌的抑菌圈直径为14~24 mm,12株乳酸菌都不具有产生物胺和偶氮还原酶的能力。通过生理和API生化鉴定确定XZJ003、XZJ006、XZJ015均为副干酪乳杆菌,通过16S rDNA和同源性确证XZJ015为副干酪乳杆菌,该研究结果对今后益生菌的深入研究和功能性食品的开发具有一定的作用。     

Detection of transgenic and endogenous plant DNA in rumen fluid, duodenal digesta, milk, blood, and feces of lactating dairy cows

The objective was to determine the presence or absence of transgenic and endogenous plant DNA in ruminal fluid, duodenal digesta, milk, blood, and feces, and if found, to determine fragment size. Six multiparous lactating Holstein cows fitted with ruminal and duodenal cannulas received a total mixed ration. There were two treatments (T). In T1, the concentrate contained genetically modified (GM) soybean meal (cp4epsps gene) and GM corn grain (cry1a[b] gene), whereas T2 contained the near isogenic non-GM counterparts. Polymerase chain reaction analysis was used to determine the presence or absence of DNA sequences. Primers were selected to amplify small fragments from single-copy genes (soy lectin and corn high-mobility protein and cp4epsps and cry1a[b] genes from the GM crops) and multicopy genes (bovine mitochondrial cytochrome b and rubisco). Single-copy genes were only detected in the solid phase of rumen and duodenal digesta. In contrast, fragments of the rubisco gene were detected in the majority of samples analyzed in both the liquid and solid phases of ruminal and duodenal digesta, milk, and feces, but rarely in blood. The size of the rubisco gene fragments detected decreased from 1176 bp in ruminal and duodenal digesta to 351 bp in fecal samples.     

食用菌深层发酵物中生物活性物质含量的比较

食用菌深层发酵物中含有很多与免疫相关的生物活性物质。本文以白灵菇、金针菇、茶树菇、平菇、香菇、桑黄、云芝和灰树花八种食用菌为实验材料,利用摇瓶深层发酵技术,对相同发酵条件下,8种食用菌发酵物中的胞外多糖、胞内多糖、黄酮、总酚、VC和可溶性蛋白含量进行了比较。结果表明,灰树花深层发酵物中总多糖产量最高为0.349 g/100 m L,桑黄中的黄酮和可溶性蛋白的产量最高分别为3.92μmol/100 m L和0.58 mg/m L,云芝中的VC产量最高为19.95 g/100 mg,金针菇的总酚产量最高为5.07 mg/100 m L。通过比较,白灵菇的综合指标表现最好,以白灵菇为实验材料进行发酵罐深层发酵,比较摇瓶与发酵罐深层发酵液中各物质的含量变化。结果表明,在发酵罐条件下,白灵菇的胞外多糖和胞内多糖产量明显提高,但黄酮和VC产量增幅不大,说明发酵条件对发酵物中活性物质产量有很大的影响。     

Detection of fruit juice adulteration in apple and pear juice

A method has been developed to detect the adulteration of pear juice with apples and apple juice with pears. In different varieties of apples and pears and in several commercial juices the flavonoids were examined by HPLC with respect to their quality and quantity. The chalcones phloretin glucoside and phloretin xyloglucoside are typical compounds found in apples (detection limit 7 ng). They are suitable indicators for detecting adulteration of pear juice with apples. Isohamnetin glucoside cannot be detected in apples (detection limit 10 ng), but can be used to detect pears in apple juice. The extract or juice was purified with the aid of a polyamide column. The evaporated eluate of methanol was analysed by HPLC (gradient: acetonitrile/1% acetic acid). An RP-18 column and a UV-detector were used. Additionally, the UV spectra of the compounds indicating an adulteration were recorded by a diode array detector.     

缓冲能力与葡萄汁饮料中原果汁含量关系的研究

对葡萄汁饮料的缓冲系数与原果汁含量之间的关系进行了研究,结果表明,缓冲系数与原果汁含量呈线性正相关,同时得出了缓冲系数与原果汁含量之间的关系式。只要测定出该饮料的缓冲系数,即可根据关系式推算出该饮料中原果汁含量。该方法的相对标准偏差0.37%~1.13%,回收率106%~108%,具有较高的准确度和精确度,且方法简便、快速,可用于葡萄汁饮料中原果汁浓度的检测。     

桑葚汁、茱萸汁和沙棘汁中的总黄酮含量测定分析

在硝酸铝-醋酸钾分散系中,用乙醇浸提,采用可见光分光光度计测定桑葚汁、茱萸汁和沙棘汁3种果汁中的总黄酮含量.在波长500 nm条件下,以芦丁为标准品做标准曲线得回归方程:Y=0.5705X-0.0065,R2=0.9995.分别测得桑葚汁中的黄酮含量为891.710 mg/100mL、茱萸汁为147.349 mg/100mL、沙棘汁为321.647mg/100mL.     

Changes in orange juice color by addition of mandarin juice

The most natural way of improving the color of orange juices is by adding other juices, which provide a more intense coloration. The US legislation allows the addition of up to 10% of mandarin juice to the orange juice to improve its color. The first objective of this study was to compare the color characteristics of juices from 11 mandarin cultivars, currently being grown in Spain. Experimental results proved that only the green-red coordinate, a*, of the orange juices can be improved by adding mandarin juice. The mandarin cultivar that provided a juice with the highest values of a* was Clemenules. Once this selection was made, the effects of adding mandarin juice at different ratios, up to 10%, on the color characteristics of the orange juice were studied. Values of the a* coordinate went from 5.50 for the pure orange juice up to 6.29 for the mixture of 90% orange juice plus 10% of mandarin juice. Finally, hedonic tests proved that regular juice consumers preferred the color of mandarin juice to that of orange juice and that they liked better the color of the juice mixture containing 10% mandarin juice than that containing 3% mandarin juice.     

Rheological behaviour of apple juice and pear juice and their concentrates

This paper reports the rheological behaviour of apple juice and pear juice. The effect of temperature on this behaviour for concentrated apple juice and pear juice of 71°Brix and 70°Brix, respectively, is examined and equations are given to describe the change in viscosity with temperature within the temperature range 5–60°C. The rheology of apple juice and pear juice of different soluble solids concentrations at 25°C is likewise reported with equations to relate the change in viscosity with concentration within the concentration range studied. In all these cases these juices are Newtonian in behaviour.     

荔枝果汁及其果汁饮料的研制

研究了荔枝汁及荔枝汁饮料的工艺过程和产品的质量指标．同时也研究了影响荔枝汁稳定的因素以及在室温贮藏过程中护色剂对荔枝汁色泽变化的影响．     

鲜榨苹果汁与浓缩苹果汁酿酒特性的比较

以苹果鲜榨汁和浓缩汁为原料,分别通过添加蔗糖和稀释的方式使发酵起始糖度为200g/L进行酒精发酵。对发酵产品的常规理化指标和总酚,总类黄酮以及黄烷醇含量进行测定,并对发酵产品进行感官鉴评。实验结果表明:稀释浓缩汁和鲜榨果汁酒样总酸含量分别为2.6g/L和3.2g/L。鲜榨果汁酒样总酚含量、总类黄酮以及黄烷醇含量均高于稀释浓缩汁酒样。两种酒各具特色,鲜榨汁酒样果香浓郁,稀释浓缩汁酒样酒香醇厚。      

黑莓原果汁及其果汁饮料加工

根据黑莓果实的组织结构及理化性状特点，比较了原果汁不同提取方法对所含成分的影响，提出了保持黑莓原有色泽、风味和营养成分的原果汁及其饮料生产工艺流程和技术条件。     

几种制汁葡萄在新疆生长情况调查及果汁品质分析

试验采用田间调查、果汁品质测定等方法对奥托玫瑰(Muscat Ottonel)、康拜尔早生(CampbellEarly)、卡它巴(Catawba)、白香蕉(Triumph)、玫瑰香(Muscat Hamburg)、香槟(Champion)、康太、黑虎香、一品香、郑果25号、柔丁香、黑贝蒂12个制汁葡萄品种在新疆的生长情况及果汁品质进行了相关的研究。结果表明:郑果25号、康太、卡它巴、康拜尔早生、黑贝蒂、黑虎香、一品香、柔丁香、香槟、白香蕉的综合性状优良,具有生长好、抗病性强、果实性状好和果汁品质优良等特点。     

柑橘果茸与果汁联产工艺技术

利用柑橘果茸与果汁联产的工艺.充分提高了原料的利用率,增加了柑橘加工产品的花色品种,经加工测试,提出最适合果茸与果汁联产的品种为晚熟温州蜜柑,为解决柑橘滞销提供了新的途径.     

特色蟠桃西瓜苹果醋饮料的研究

介绍了苹果醋的酿制方法及最佳工艺条件,并以苹果醋为酸味剂,辅以蟠桃汁、西瓜汁、苹果汁、蜂蜜等,研制出集营养、保健、风味于一体的果醋果汁饮料.     

果胶酶提高葡萄出汁率及色泽的影响

研究用果胶酶提高葡萄出汁率的方法及果胶酶对葡萄汁色泽的影响.通过单因素与正交试验分析酶添加量、酶解温度和酶解时间对葡萄出汁率的影响,结果表明：最佳工艺条件为：果胶酶用量0.1 mL/kg,酶解温度55℃,酶解时间50 min.