腰果全粉微胶囊化工艺及其性质结构的表征

以腰果为主要原料研制微胶囊化腰果全粉,优化生产工艺,并对产品的理化性质进行表征。结果显示,乳化剂配比单双甘脂蔗糖酯(质量比)为12时乳化稳定性最好,乳化剂添加量1.5%最为合适,芯壁比(质量比)以11为最佳,最佳固形物含量为25%。微胶囊基本成分为蛋白质12.94%、水分2.38%、碳水化合物61.57%、灰分2.45%、脂肪20.66%。微胶囊包埋率为94.23%、密度为0.68g/cm3、自流角为35.45°、溶解度为92.91%、吸湿性为0.77%。复原乳乳化效果好,溶液较为稳定,粒径主要在353.3nm左右。扫描电镜测定结果显示:腰果微胶囊颗粒为饱满的球形,分布均匀,多数直径处于25μm左右,包埋效果良好。     

Isolation and characterization of protein isolated from defatted cashew nut shell: Influence of pH and NaCl on solubility and functional properties

This work reports the isolation of protein from defatted cashew nut shell (CNS), with the crude protein product containing 91.07% protein. Under its natural conditions, the solubility of this protein isolate is comparable (74.02%) to that of mustard green meal protein. The solubility of the protein isolate decreases with decreasing pH, with the minimum solubility observed at its isoelectric point (pH 3). The water holding capacity, oil holding capacity, foaming capacity, foam stability, emulsifying capacity and emulsion stability were found to be 2.56 cm³ H₂O/g protein, 4.28 cm³ oil/g protein, 76.88%, 70.98%, 62.0% and 79.0%, respectively. The profiles of these functional properties were determined with varying pH values and NaCl concentrations, and improved properties were observed in the alkaline pH range and in the presence of NaCl. Electrophoretic analysis showed that the high molecular weight protein globulin was the major protein in the protein isolate.     

红松种子水溶性蛋白吸水性、吸油性及溶解性的研究

选用黑龙江省伊春市红松种子为原料,以蒸馏水为提取液制备红松种子水溶性蛋白(WPNP)。研究了pH、温度、CaCl2和NaCl浓度对WPNP的吸水性、吸油性和溶解性的影响。WPNP的等电点为4,pH介于4～12之间,吸水性随着pH的增加而升高;温度处于30℃时,吸水性最好,为4mL/g;NaCl离子强度处于0·4mol/L时,WPNP的吸水性最好,为3·4mL/g;温度对WPNP的吸油性有较大的影响,在30～35℃时,WPNP的吸油性较好。但是在35～60℃范围内,随着温度的升高,WPNP的吸油性降低。研究了pH、温度、离子强度、共存盐类对WPNP溶解性的影响,pH4,随着pH增加溶解性也增加,但是pH超过12,会导致蛋白质变性,40℃时溶解性最好,为10·01mg/mL,NaCl的浓度在0·4～0·6mol/L时,蛋白质溶解度随着NaCl的浓度增加而增大,最大值为9·39mg/mL。但是NaCl的浓度再增加蛋白质溶解度反而降低。而CaCl2溶液浓度在0·6mol/L时溶解度最大,为9·12mg/mL。后随着CaCl2浓度的增大蛋白质溶解度下降。NaCl和CaCl2共存,能够促进HSZZSP的溶解,并在一定浓度后变化趋于平缓。     

腰果蛋白的功能特性研究及其氨基酸组成分析

采用碱提法最优条件提取并酸沉得到腰果蛋白,研究了p H和温度对腰果蛋白的溶解性、起泡性及起泡稳定性、乳化性及乳化稳定性、持油性等功能特性的影响,并分析了腰果蛋白的氨基酸组成。结果表明:腰果蛋白的溶解性随p H的增加呈先降低后升高的趋势,在p H4附近溶解度最低,仅为15.90%。起泡性和乳化性随p H的变化曲线与溶解度曲线一致,在p H10时起泡性和乳化性最好,分别为13.92%、24.70 m2/g。腰果蛋白的起泡稳定性随p H的增加而逐渐增加,在p H8时达到最大为9.42%,而后趋于稳定。在碱性环境中,腰果蛋白会表现出较好的乳化稳定性,并且在80℃时其持油性最佳,为2.84 g/g。氨基酸分析表明,腰果蛋白中含有17种氨基酸,其中7种是人体必需氨基酸,含量皆高于FAO/WHO/UNO成人推荐标准,赖氨酸为第一限制性氨基酸,谷氨酸和精氨酸含量最高,分别为22.46%和9.02%。     

腰果蛋白的功能特性研究及其氨基酸组成分析

采用碱提法最优条件提取并酸沉得到腰果蛋白,研究了p H和温度对腰果蛋白的溶解性、起泡性及起泡稳定性、乳化性及乳化稳定性、持油性等功能特性的影响,并分析了腰果蛋白的氨基酸组成。结果表明:腰果蛋白的溶解性随p H的增加呈先降低后升高的趋势,在p H4附近溶解度最低,仅为15.90%。起泡性和乳化性随p H的变化曲线与溶解度曲线一致,在p H10时起泡性和乳化性最好,分别为13.92%、24.70 m2/g。腰果蛋白的起泡稳定性随p H的增加而逐渐增加,在p H8时达到最大为9.42%,而后趋于稳定。在碱性环境中,腰果蛋白会表现出较好的乳化稳定性,并且在80℃时其持油性最佳,为2.84 g/g。氨基酸分析表明,腰果蛋白中含有17种氨基酸,其中7种是人体必需氨基酸,含量皆高于FAO/WHO/UNO成人推荐标准,赖氨酸为第一限制性氨基酸,谷氨酸和精氨酸含量最高,分别为22.46%和9.02%。      

Impact of γ‐irradiation and thermal processing on the antigenicity of almond,cashew nut and walnut proteins

Whole unprocessed almonds, cashew nuts and walnuts were each subjected to γ‐irradiation (1, 5, 10 and 25 kGy) followed by heat processing including autoclaving (121 °C, 15 psi for 15 and 30 min), dry roasting (138 and 160 °C for 30 min each, 168 and 177 °C for 12 min each), blanching (100 °C for 5 and 10 min), oil roasting (191 °C, 1 min) and microwave heating (500 W for 1 and 3 min). Rabbit polyclonal antibodies were raised against each major protein isolated from defatted, but not subjected to γ‐irradiation and/or any thermal processing, almond, cashew nut and walnut flours. Immunoreactivity of almond, cashew nut and walnut proteins soluble in borate saline buffer, normalised to 1 mg protein ml^?1 for all samples, was determined by inhibition enzyme‐linked immunosorbent assay (ELISA) and Western blotting. ELISAs and Western blotting experiments indicated that almond, cashew nut and walnut proteins exposed to γ‐irradiation alone or followed by various thermal treatments remained antigenically stable. Copyright © 2004 Society of Chemical Industry     

Effect of salting and roasting on the carbohydrates and proteins of Iranian pistachio kernels

The free sugars which make up 2.7% of Iranian pistachio cv Badami were identified as fructose, glucose, sucrose, maltose, isomaltose, cellobiose, raffinose and stachyose. Both protein and free amino acids contained the same seventeen amino acids but lacked tryptophan, asparagine and glutamine. After salting and roasting, total available carbohydrates, total starches and dextrins, and total free sugars all decreased compared to controls, as did a number of individual sugars, especially the reducing sugars. While free amino acids had severely decreased, total protein amino acids and individual protein amino acid were not affected at all. The decreases in reducing sugars and in free amino acids may be due in part to their taking part in Maillard reactions.     

一种全自动腰果脱壳机的脱壳试验研究

为了进一步提高腰果脱壳机的脱壳效果,分别研究了推果速度、切刀装置中弹簧压缩距离及进果时腰果的状态等因素对脱壳过程中整仁率、滑果率及躺果率的影响。结果表明:推果速度对腰果脱壳机的脱壳效果(整仁率、滑果率及躺果率)影响极显著(P0.01);弹簧压缩距离对腰果脱壳过程中整仁率的影响极显著(P0.01),对滑果率及躺果率影响不显著(P0.05);进料时腰果的状态对脱壳过程中整仁率和滑果率影响极显著(P0.01),对躺果率影响不显著(P0.05);当刀口距离9.1 mm,推果速度19.8r/min,弹簧压缩距离16.70mm,采用方式a1进果时,整仁率为69.76%。     

腰果主要过敏原Ana o 2原核表达及免疫学鉴定

目的 构建Ana o 2重组表达质粒,原核表达重组蛋白并评价其免疫活性。方法 将Ana o 2基因构建到pET-28a(+)载体中,测序正确的重组质粒转化Rosetta(DE3)感受态细胞,诱导表达目的蛋白并进行质谱鉴定。利用腰果过敏阳性血清,通过酶联免疫吸附试验(ELISA)和蛋白质免疫印记(Western blot)法评价重组Ana o 2的免疫活性。结果 重组蛋白进行十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDS-PAGE)表明分子量为54 kD,与理论值相符,经质谱鉴定为Ana o 2。ELISA结果显示,用重组Ana o 2检测腰果过敏阳性血清与阴性血清特异性IgE抗体(sIgE)水平差异有统计学意义(t=2.44,P<0.05)。Western blot结果表明,重组Ana o 2与腰果过敏患者血清反应性良好。结论 利用原核系统表达了Ana o 2,并且重组Ana o 2与腰果过敏患者血清具有良好的反应性。     

腰果主要过敏原Ana o 3的重组表达与鉴定

目的克隆获得腰果主要过敏原Ana o 3基因,并利用pCold-SUMO原核表达载体重组表达Ana o 3并鉴定免疫活性。方法提取腰果总RNA,逆转录至c DNA,设计特异性引物,通过巢式PCR技术克隆腰果Ana o 3基因,将其插入pCold-SUMO vector,鉴定并测序;将测序正确的阳性质粒转化大肠埃希菌BL21(DE3),低温15℃诱导表达。摸索诱导表达条件,经镍柱纯化,并通过Western blot鉴定免疫活性。结果测序结果表明,克隆腰果Ana o 3基因片段全长为417 bp,与GenBank上Ana o 3基因CDS序列基本一致;十二烷基硫酸钠聚丙烯酰胺凝胶电泳结果表明,目的蛋白分子量为27 kD左右,大小与理论值相符;Western blot结果表明,与腰果过敏阳性血清具有良好的反应性。结论从腰果中成功克隆了Ana o 3基因,并于原核系统表达了Ana o 3蛋白,证实了此蛋白与腰果过敏血清具有良好的反应性。     

大豆致敏蛋白致敏机制研究

采用酶联免疫印迹实验对脱糖基前后大豆致敏蛋白的致敏性进行识别,发现脱糖基后大豆致敏蛋白的致敏性依然存在,说明糖基不是引起致敏的主要原因;对模拟胃肠道消化后大豆致敏蛋白的致敏性进行识别.发现消化后大豆致敏蛋白已被水解,水解后的蛋白不与患者血清中的IgE抗体结合,说明正常消化情况下的大豆蛋白不易引起人体过敏.     

Effect of chemical phosphorylation on solubility of buffalo milk proteins

Buffalo milk proteins (casein, co-precipitate or whey protein concentrate) were phosphorylated with phosphorus oxychloride (POCl₃) at three different pH values (5.0, 7.0 and 9.0). The solubilities of phosphorylated milk proteins were examined over the pH range 3.0–9.0 in water and ionic (0.1 m NaCl or 10–70 mm Ca²⁺) systems. The solubilities of buffalo milk proteins decreased at pH 3.0, while there was an increase in the solubilities of casein and co-precipitate near their isoelectric points upon phosphorylation. Solubilities of these phosphorylated milk proteins were pH dependent in 0.1 m NaCl but there was a decrease in their solubilities with increase in calcium ion concentration. This alteration could be due to the shifting of isoionic points of phosphorylated buffalo milk proteins towards acidic pH.     

The influence of post-mortem ageing and roasting on the microstructure, texture and collagen solubility of bovine semitendinosus muscle

Bovine semitendinosus (ST) muscles aged for 5 and 12 days at 4?°C were roasted at 170?°C to internal temperatures of 50, 60, 70, 80 and 90?°C. Microstructural changes in meat were evaluated using a scanning electron microscope (SEM). Texture profile analysis (TPA) and measurements of the shear force values of samples were conducted using a texture analyser. The cooking losses and quantity of total and soluble collagen were also estimated. The structure of intramuscular connective tissue and myofibrillar structure of meat after 5 days of ageing was very regular. In 12-day-aged samples fibrous and myofibrillar structures were less distinct, damages of endomysium tubes appeared and fibres of perimysium were swelled. Ageing of ST muscle for 12 days caused a two-fold increase in the quantity of soluble collagen and a two-fold decrease in the value of TPA parameters-hardness and chewiness, as compared to 5-day-aged samples. The decrease in fibre diameter and sarcomere length during roasting started at 60?°C in 5-day-aged meat and at 50?°C in 12-day-aged samples. The shear force values measured after roasting were lower for 12-day-aged meat than for 5-day-aged samples. The quantity of soluble collagen in roasted meat increased at an internal temperature of 80?°C. At a higher temperature of meat this variable depended on the degree of meat ageing. The cooking losses during roasting of meat were about 3% lower for 12-day-aged than for 5-day-aged samples. In the examined range of internal temperature of meat the cooking losses and the sarcomere length were negatively correlated.     

Functional properties of raw and heat processed cashew nut (Anacardium occidentale, L.) kernel protein isolates

The functional properties viz. solubility, water and oil absorption, emulsifying and foaming capacities of the protein isolates prepared from raw and heat processed cashew nut kernels were evaluated. Protein solubility vs. pH profile showed the isoelectric point at pH 5 for both isolates. The isolate prepared from raw cashew nuts showed superior solubility at and above isoelectric point pH. The water and oil absorption capacities of the proteins were slightly improved by heat treatment of cashew nut kernels. The emulsifying capacity of the isolates showed solubility dependent behavior and was better for raw cashew nut protein isolate at pH 5 and above. However, heat treated cashew nut protein isolate presented better foaming capacity at pH 7 and 8 but both isolates showed extremely low foam stability as compared to that of egg albumin.