天然红菜苔色素的提取及稳定性研究

本报道了分别采用甲醇、乙醇、水作为溶剂提取红菜苔色素的工艺及光谱特性,其最大吸收峰为530nm;并针pH值、光、热等因素对其稳定性的影响作了深入研究。     

Emulsifying and Foaming Properties of Different Protein Fractions Obtained from a Novel Lupin Variety AluProt‐CGNA® (Lupinus luteus)

The use of vegetable proteins as food ingredient is becoming increasingly important due to their high versatility and environmental acceptability. This work describes a chemical characterization and techno‐functional properties (emulsifying and foaming properties) of 3 protein fractions obtained from a protein‐rich novel lupin variety, AluProt‐CGNA^®. This nongenetically modified variety have a great protein content in dehulled seeds (60.6 g protein/100 g, dry matter), which is higher than soybean and other lupin varieties. A simple procedure was utilized to obtain 3 different fractions by using alkali solubilization and isoelectric precipitation. Fractions 1 and 3 were mainly composed of protein and polysaccharides (NNE), whereas fraction 2 was mainly composed by protein (97%, w/w). Fraction 3 presented interesting and potential foaming properties in comparison to the other fractions evaluated in the study. Besides, its solubility, foaming and emulsifying capacity were practically not affected by pH variations. The 3 fractions also presented good emulsion stability, reaching values above a 95%. SDS‐PAGE showed that fractions 1 and 2 contained mainly conglutin α, β, and δ, but in different ratios, whereas fraction 3 contained mainly conglutin γ and albumins. The results of this work will provide better understanding for the utilization of each protein fractions as potential ingredients in food industry.     

The fatty acid composition of the oil from Lupinus albus cv. Luxe as affected by environmental and agricultural factors

There is a growing interest in white lupin (Lupinus albus L.) seed for food or feed, favoured by the availability of well-performing varieties with low content of alkaloids. The objective of this study was to assess the influence of the environmental and agricultural factors on the content and fatty acid composition of lupin oil. The investigation was performed on the sweet variety Luxe grown in three Italian locations (one continental and two Mediterranean) and 13 environments in total. Statistical analyses (analysis of variance and principal component analysis) indicated that oil content and composition of fatty acids were affected largely by the growing location. Mediterranean sites tended to lower crop yield, but to increase oil content and absolute α-linolenic acid content compared to the continental location; large variation occurred also between the Mediterranean sites. The α-linolenic acid content ranged from 1.41 to 3.24 mg/g flour, highlighting the possible value of white lupin in order to reach the recommended daily intake of this fatty acid. The observed ω-3/ω-6 ratio, ranging from 0.45 to 0.63, was much higher than that of most vegetable oils.     

一株野油菜黄单胞菌产黄原胶的性质

通过发酵一株野油菜黄单胞菌得到黄原胶,进而测定该黄原胶在不同质量浓度、pH值、氯化钠质量浓度、温度下黏度变化,分析黄原胶流变特性、丙酮酸质量分数和黏均分子质量。结果表明：本实验菌株的黄原胶产量达到28.4 g/L,黄原胶黏度在质量浓度高于4.0 g/L时迅速升高,黄原胶黏度在pH 3.0～10.0之间稳定。氯化钠质量浓度由10 g/L增加到70 g/L时,使1.0 g/L黄原胶黏度提高20%,而温度高于35 ℃时使1.0 g/L黄原胶黏度降低。黄原胶的丙酮酸质量分数达到6.35%,黏均分子质量为5.7×106 D。1.0 g/L黄原胶的稠度系数和流体指数分别为26.94和0.765 5,5.0 g/L黄原胶的稠度系数和流体指数分别为489.65和0.328 1。研究表明该株野油菜黄单胞菌具有较大的潜在应用价值。     

不同栽培方式对鸡毛菜贮藏保鲜品质的影响

目的 探究不同栽培方式(土壤栽培、营养液栽培、基质栽培)对鸡毛菜保鲜品质的影响。方法 采用理化分析、感官评定和多指标GSI(general stability index)综合分析方法, 测定了含水量、叶绿素、维生素C、硝态氮等品质指标。结果 不同的栽培方式对鸡毛菜营养品质和保鲜指标存在不同的影响; 土壤栽培方式下, 硝酸盐含量远远高于其他两种栽培方式。结论 无土栽培的鸡毛菜营养品质优于土壤栽培; 随着贮藏时间的延长, 鸡毛菜的品质逐渐衰退, 在4 ℃的低温贮藏条件下, 适宜的保质期为5天。     

Primary structure of 2S albumin from seeds of Lupinus cosentinii

 The 2S albumin from seeds of Lupinus cosentinii Guss. was purified, and the complete amino acid sequences of the dominating small and large subunit were determined by automated Edman degradation of the reduced and S-pyridylethylated polypeptides and of their enzymatic fragments. The small subunit of the 2S albumin consists of 35 amino acid residues resulting in a molecular mass (M _r) of 4233. The large subunit contains 73 amino acid residues (M _r = 8627). The two polypeptide chains are linked by two interchain disulphide bonds. In addition, the large polypeptide contains two intrachain disulphide bridges and one free sulphydryl group. A high degree of homology (88–89%) exists between the primary structure of the 2S albumin from L. cosentinii and those from other Lupinus species. The positions of the cysteines and of some other amino acids are conserved not only in most of the Dicotyledoneae 2S albumins sequenced so far but also in other storage proteins. Received: 26 May 1997     

野油菜黄单胞菌基因组DNA快速提取方法和酶切

本文建立了一种野油菜黄单胞菌(Xanthomonas campestris)基因组DNA的简便快速提取方法。用去污剂SDS和CTAB破坏细胞膜结构,使胞内核酸释放,用酚/氯仿/异戊醇去除蛋白质,经异丙醇沉淀DNA,TE溶解DNA。采用此SDS和CTAB结合的方法提取的DNA琼脂糖电泳图谱与试剂盒UNIQ-10提取的基因组DNA及D-5010A试剂盒法提取的基因组DNA图谱相同,DNA经紫外分光光度计检测OD260/OD280在1.80～1.90之间。DNA能被EcoRI、XbalI酶切消化。本方法能快速简便地提取野油菜黄单胞菌DNA,提取的DNA含量较高、纯度较好,比试剂盒更经济,也可用于酶切分析、构建文库和PCR扩增。     

混合烷烃对野油菜黄单胞菌合成黄原胶的影响

本实验研究野油菜黄单胞菌以玉米淀粉作为碳源进行黄原胶生物合成过程中,添加作为携氧剂的混合烷烃对提高产胶率的影响,同时电镜观察不同发酵时期野油菜黄单胞菌的产胶情况。在摇瓶发酵的基础上,进行发酵罐实验。添加8%混合烷烃发酵66h后,黄原胶产胶率和碳源转化率明显提高。结果显示:摇瓶发酵产胶率可达3.84%(对照组为2.58%),碳源转化率为76.8%(对照组为51.6%);发酵罐产胶率可达4.18%(对照组为2.90%),碳源转化率为83.6%(对照组为58.0%)。     

Effect of different pasteurization conditions on bioactivities of Lupinus albus protein isolates

Lupin protein isolate was extracted following the procedure in European Patent (EP 1024 706 B1) in order to use lupin protein for food and pharmaceutical applications. The acid insoluble/neutral pH soluble protein isolate was pasteurized at 65-125 °C for 10-1000 s. The objective of this study is finding out reasonable pasteurization condition for food use, or for good bioactivities like radical scavenging, angiotensin converting enzyme inhibition, and bile acid binding activity. Pasteurization at 65 °C for 10 s did not reduce the microbial count of the protein sufficiently for use in foods. The chemical composition of lupin protein isolates had no change by various pasteurization. The angiotensin converting enzyme inhibition decreased and the DPPH radical scavenging capacity increased after high temperature treatment at 125 °C. The sodium cholate binding capacity was not affected by tested conditions. Pasteurization at higher temperature is useful for producing selective bioactive fractions with suitable microbiological properties.     

海藻酸钙固定化对Xanthomonas campestris206冰核活性的影响

应用正交法研究了海藻酸钙固定化对Xanthomonascampestris 2 0 6冰核活性的影响。结果表明 ,对固定化小球冰核活性影响程度大小的顺序依次为 :菌悬液用量 >海藻酸钠用量 >CaCl2 浓度 >固化时间 ,而对渗漏量影响程度大小的顺序依次为 :菌悬液用量 >固化时间 >CaCl2 浓度 >海藻酸钠用量。研究中还发现 ,将冰核活性细菌固定化在热稳定性方面实际意义不大。