花生四烯酸油微胶囊配方优化及稳定性研究

采用喷雾干燥法制备花生四烯酸油微胶囊,以花生四烯酸油微胶囊的包埋率为评价指标,对变性淀粉用量、酪蛋白用量、蔗糖用量、芯材含量的配方进行了响应面设计实验。实验得到的花生四烯酸油微胶囊最佳配方为:变性淀粉用量9.04%,酪蛋白用量6.41%,蔗糖用量5.36%,芯材含量30.38%。由最佳配方得到的花生四烯酸油微胶囊的包埋率达到93.26%,产品经62℃加速氧化45 d后,过氧化值仅为对照样品的1/10,氧化稳定性显著。将花生四烯酸油微胶囊添加在婴儿配方奶粉中,经充氮包装贮藏1年,花生四烯酸保留率为93.01%,证明该微胶囊具有良好的贮藏稳定性。     

花生核桃乳感官品质的模糊数学评价

以色泽、气味、滋味、杂质为评价因素,对6种品牌花生核桃乳的感官品质进行模糊数学判定。结果表明:6种花生核桃乳感官品质的模糊综合感官评价得分从高到低为S_6S_2S_5S_1S_3S_4,其中6号样品的模糊判定级别最优,4号样品最差。     

DHA对营养补充剂感官影响初探

初步研究在营养补充剂中添加一定剂量藻油DHA或鱼油DHA对口感、气味和色泽的影响。试验口感评价采用单盲测试方法,感官结果采用打分制,Spss 17.0进行数据分析。测试样品气味、色泽和口感的方差结果显示:(1)补充剂中添加40~80 mg的DHA不会对补充剂带来气味、口感和色泽方面的显著影响;(2)考虑口感、婴幼儿营养和经济效益,选择添加40 mg藻油DHA的补充剂并且及时食用是最佳的。因此,通过初探营养补充剂添加DHA的感官评价,说明添加一定量的DHA是可行的,对补充剂的品质基本不影响。     

花生水解蛋白的功能性质研究

对花生水解蛋白的溶解性和乳化性质进行了研究.结果表明,花生水解蛋白在碱性条件下溶解度较好;提高温度可增加花生水解蛋白乳化活性,在远离等电点时花生水解蛋白具有较好的乳化活性,而乳化稳定性随PH变化未呈现规律性变化.增加花生水解蛋白浓度或添加可溶性淀粉均可显著改善该蛋白质的乳化性能.     

花生肽亚铁金属配位螯合物结构解析及稳态性研究

该试验采用紫外（UV）光谱和傅里叶变换红外（FTIR）光谱对制备得到的花生肽亚铁金属螯合物的结构进行确认,同时考察 了其热稳定性、pH稳定性及醇溶性。 紫外光谱结果表明,花生肽与亚铁进行了有效螯合;FTIR分析结果表明,亚铁离子可能与花生肽 配体的羰基以共价配位键形成共轭结构环,花生多肽中氨基N与羧基O均参与亚铁配位螯合。 结构稳态性研究结果表明,花生肽亚铁 在温度10～60 ℃范围内和pH值1～8范围内均保持较好的稳定性,亚铁螯合率均＞80%;醇溶性试验结果表明,在纯水和10%稀乙醇 溶液中,花生肽亚铁保持较好的溶解性,溶解性达到95%以上,高浓度乙醇溶液中溶解性变差。 结果表明,花生肽亚铁具有很好的热 稳定性和pH稳定性,在纯水和体积分数10%的稀醇溶液中保持较好的溶解性。     

DHA/AA在婴幼儿配方乳粉添加中氧化稳定性的研究

研究针对二十二碳六烯酸(DHA)和花生四烯酸(AA)是现在婴幼儿乳粉中营养强化剂添加的重点,这2种成分对婴幼儿的健康成长和发育起着重要的作用,但这2种不饱和酸极易被氧化,选择稳定性好的产品是决定乳粉品质的重要因素。对市售的5个厂家的二十二碳六烯酸(DHA)和花生四烯酸(AA)微胶囊产品进行了过氧化值(POV)的测定,分析DHA和AA在婴儿配方乳粉中稳定性。     

ARA及DHA粉剂稳定性检测方法研究

分别采用食品氧化性测定仪(OXI)检测方法与传统的恒温箱(60℃)加速稳定性方法研究了花生四烯酸(ARA)及二十二碳六烯酸(DHA)微胶囊粉末产品的稳定性,结果显示:这2种方法均能较好检测出ARA和DHA粉剂的稳定性。而OXI检测方法较传统方法具有连续性好,实验用时短,样品用量少等优点。但是OXI不能反映微胶囊粉末样品的溶解情况,因此在进行OXI实验的同时在60℃条件下观察样品的颜色变化并定期进行样品溶解是一个较好的评价ARA和DHA粉剂稳定性的实验方法。     

红薯大豆高蛋白复合饮料的研制

以红薯、大豆、花生和白砂糖为原料,研制一款新型的高蛋白复合饮料。通过单因素试验和正交试验并对样品进行感官评价,通过数据分析确定红薯大豆花生高蛋白复合饮料的最佳风味配方,同时进行饮料稳定性的研究。结果显示,红薯大豆花生高蛋白复合饮料的最佳配方是:红薯汁添加量30 mL,大豆汁添加量30 mL,花生汁添加量10 mL,白砂糖添加量7 g。稳定剂最佳方案是:0.1%海藻酸钠和0.2%明胶复配。所制得产品具有红薯、大豆和花生所产生的复合风味,色泽均匀,组织状态良好,是一种营养丰富的高蛋白复合饮料。     

烘焙型蛋黄酱制作配方及稳定性研究

为提高蛋黄酱在烘焙中的应用价值,以烘焙型蛋黄酱为研究对象,通过模糊数学感官综合评价法对其组织形态、色泽、气味、口感进行感官评分,结合正交试验得出烘焙型蛋黄酱的制作配方,并采用耐高温和耐低温测试对蛋黄酱进行稳定性试验。结果表明最优配方为蛋黄添加量14%、大豆油添加量70%、白醋添加量9%、变性淀粉添加量4%。该配方制作的焙烤型蛋黄酱稳定性较好,耐高温烘烤,适合应用于烘焙中。     

不同储存方式对榛子油品质的影响

采用真空、充氮气、添加抗氧化剂3种方式处理榛子油,通过高温强制氧化缩短榛子油试验观察期,以色泽、气味、过氧化值、酸值、羰基值为判断榛子油品质的指标,试验储存榛子油的方法。试验结果表明,经过60℃20 d的强制氧化后,空白、真空、充氮气、充氮气+0.01%TBHQ、0.02%TBHQ 5种方式处理的榛子油样品的色泽均加深,添加0.02%TBHQ样品的气味未变,其他均有哈败气味;随着强制氧化时间的延长,空白、真空、充氮气的榛子油样品的过氧化值、酸值、羰基值均显著升高,充氮气+0.01%TBHQ、0.02%TBHQ处理的榛子油样品的过氧化值、酸值、羰基值升高缓慢,过氧化值升高的幅度最小;添加0.02%TBHQ可以有效地延长榛子油保质期,并保持其感官品质。     

Biochemical factors influencing metmyoglobin formation on beef from muscles of differing colour stability

Biochemical parameters, such as oxygen consumption rate by muscle post mortem (OCR), depth of oxygen penetration into meat, rates of myoglobin oxygenation and deoxygenation and myoglobin content and succinic dehydrogenase activity, were determined for muscles of differing colour stability. Metmyoglobin reduction, in anoxia following oxidation with ferricyanide (MRA) and aerobically following oxidation with low pO(2) (ARA), were also determined. M. psoas major (poor colour stability) has higher enzymic activity than M. longissimus dorsi (good colour stability). This difference, together with the low myoglobin content in M. psoas major, results in relatively high OCR with consequent low oxygen penetration and rapid conversion of oxymyoglobin to myoglobin in M. psoas major, disposing it to rapid formation of metmyoglobin. Metmyoglobin reduction occurs both under anaerobic and aerobic conditions but no significant correlation is found between actual metmyoglobin reduction and rate of discoloration of different muscles. The most significant factor affecting colour stability of beef muscles appears to be their enzymic activity which determines the rate of myoglobin oxidation.     

Stability and use of natural colours in foods Red beet powder, copper chlorophyll powder and cochineal

Three natural pigments – red beet powder, chlorophyll powder (in the form of a copper complex) and aqueous cochineal – were examined in order to understand better their behaviour or colouring ability in different model systems. All were heat labile but red beet colour in particular was rapidly degraded above about 14°C. Cochineal proved the most stable of the three colours. All were adversely affected by changes in pH and a reduction in water activity gave a corresponding increase in stability for each colour. Light was similarly shown to cause degradation of the natural colours. The colours were used in food products and shown to have certain applications with regard to the colour of jam and restoring the colour of peas after blanching.     

Characterisation of anthocyanin–betalain mixtures for food colouring by chromatic and HPLC-DAD-MS analyses

Anthocyanins and betalains that are mutually exclusive in nature were mixed to investigate their potential synergism for food colouring purposes. The blends obtained from four commercial anthocyanic (black carrot, elderberry, sour cherry and strawberry) and one betalainic extract (red beet) were studied with respect to colour evolution over three weeks. While new colour shades were produced by blending anthocyanins with betalains, chroma and hue angle of the mixtures changed over time. The greatest number of new colour shades with acceptable chroma was obtained at pH 4.5 and 5, the stability maxima of red beet, succeeded by pH 3.0. Interestingly, at pH 3.5 only one combination yielded an acceptable chroma, whereas at pH 7 no mixture was stable. To determine individual anthocyanins and betalains in mixtures in a single run, a HPLC method was developed and combined with a mass spectrometer for the identification of specific pseudomolecular and daughter ions.     

Effect of commercial mannoproteins on wine colour and tannins stability

Commercial oenological products containing mannoproteins have the purpose of preventing tartrate salts precipitation or achieving wines with a better mouth-feeling. The evaluation of the influence of three commercial mannoproteins on colour and tannin stability of three different red wines (two from Touriga Nacional and one from Alfrocheiro and Aragonês varieties) was studied. The evolution of colour through time was similar for all modalities, resulting in an increase of polymeric pigments and colour hue and a decrease of other parameters, suggesting that there was no influence of commercial mannoproteins on colour stability. The tannin profile evolution showed a possible stabilizing effect of one of the commercial products for tannins with an mDP between 8 and 14. It is possible that the commercial mannoproteins used in this work have some influence on the tannin aggregation evolution, contributing to the delay of tannin polymerisation in red wines.     

草鱼鱼鳞胶原蛋白的提取及其理化性质研究

以草鱼鱼鳞为原料,在低于蛋白变性温度的条件下提取酸溶性胶原蛋白(ASC)和酶溶性胶原蛋白(PSC),并对其理化性质进行系统测定。实验结果表明,ASC 和PSC 的热变性温度分别为30～35℃和28～35℃; PSC 在溶解性能、乳化性能和乳化稳定性方面优于ASC,而在溶液黏度、吸水性能、吸油性能、起泡性以及泡沫稳定性方面,ASC 明显好于PSC。     

Impact of the extraction procedure on the kinetics of anthocyanin and colour degradation of roselle extracts during storage

BACKGROUND: The stability of anthocyanins and colour of aqueous extracts from roselle (Hibiscus sabdariffa L.) was investigated during storage at 4–45 °C. The effect of the extraction procedure (cold or hot extraction with or without pasteurisation) on the kinetic behaviour was determined. RESULTS: Data analysis showed first‐order kinetics for the evolution of anthocyanin content, colour density, colour strength and browning index. Three models (Arrhenius, Eyring and Ball) were used to represent the temperature dependence of the reaction rates. The three models allowed the prediction of colour modifications according to the storage temperature over 6 months. Activation energies ranged from 22 to 26 kJ mol^?1 for anthocyanin degradation and from 18 to 34 kJ mol^?1 for colour parameter modification. The degradation rate during storage depended on the extraction procedure. When heated, the extracts were clearly less stable. Their colour changed faster during storage especially when hot water and pasteurisation were used. CONCLUSION: Although the anthocyanin content and initial colour were not modified, the extraction conditions, especially temperature, greatly affected the stability of the extracts during storage. Further studies are needed to understand the mechanisms involved. Copyright © 2011 Society of Chemical Industry     

A preliminary study of the quality attributes of a cloudy wheat beer treated by flash pasteurization

Flash pasteurization (37 and 100 pasteurization units, PU) and conventional tunnel pasteurization (15 PU) processing of wheat beers were evaluated by examining their impacts on microorganisms, colour, colloidal haze and flavour stability during 84 days of storage at 20°C. The results revealed that the microbiological stability of 37 and 100 PU flash‐pasteurized beers was comparable with that of the 15 PU sample, and the development of both yeast and lactic acid bacteria was inhibited for 84 days of storage. The conventional tunnel‐pasteurized wheat beer resulted in a higher thermal load relative to the flash‐pasteurized samples based on the results of oxidative stability. These three pasteurized beers showed a similar decrease in haze intensity throughout the storage period. Meanwhile, flash‐pasteurized beers had better colour and colloidal haze stability than the tunnel‐pasteurized beer. It was also found by dynamic light scattering analysis that the temperature in the flash pasteurizer has the desired effect on the protein denaturation and particle size distribution. Therefore, flash pasteurization is a promising method to increase the shelf‐life of wheat beers instead of conventional tunnel pasteurization. Copyright © 2017 The Institute of Brewing & Distilling     

Effect of adding natural antioxidants on colour stability of paprika

We analysed the effect of adding rosemary and tocopherol extracts, two natural antioxidants, on the colour stability of paprika stored at different temperatures and degrees of relative humidity. Any possible synergistic effect of their joint use was also investigated. The experimental data concerning colour loss, as determined by the ASTA 20.1 method, fitted first‐ and second‐order kinetics, which provided the rate constants of colour loss and half‐lives of the samples. The first finding concerned the antagonistic effect between storage temperature and humidity. The antioxidants had a clear protective effect on colour stability in all the conditions assayed, the superior effect of one or the other depending on the storage temperature. A synergistic effect of both antioxidants at temperatures between 25 and 40 °C was evident. The experimental data referring to colour loss for most of the storage conditions assayed fitted second‐order kinetics best. © 2002 Society of Chemical Industry     

五大连池重碳酸矿泉水中二价铁离子稳定方法研究

优选一种或多种五大连池重碳酸矿泉水中亚铁离子的稳定剂。通过在五大连池重碳酸矿泉水中加入柠檬酸、抗坏血酸和富马酸3种稳定剂,考察矿泉水的pH值在6.0～3.0范围内变化时,矿泉水中天然二价铁离子的含量及稳定效果,并综合考察了二氧化碳的填充对矿泉水中价铁离子稳定效果的影响。调节pH≤5.5时,柠檬酸和抗坏血酸对二价铁均有较好的稳定效果,矿泉水中二价铁含量分别大于10mg/L及38mg/L,样品均为透明澄清液。但是,添加抗坏血酸的样品经过长时间保存,颜色变为橙黄色,影响了产品的稳定性。添加富马酸的样品在pH≤4.0时,二价铁离子含量为25mg/L,但是在较短时间内就产生沉淀。柠檬酸是天然矿泉水中二价铁离子的优良稳定剂。二氧化碳对二价铁离子的稳定有一定的影响作用。     

Correlation between visual and instrumental colour measurements of orange juice dilutions: effect of the background

The colour of 21 ultrafrozen orange juice samples was measured by spectroradiometry. Each sample was diluted with distilled water to obtain eight levels of concentration (10%, 25%, 40%, 50%, 60%, 75%, 90% and 100% of juice). Measurements were made against both a white and a black background. The results showed that the colour parameters which best correlated with orange juice concentration were different depending on the background used. The correlation between sensory and instrumental measurements was also evaluated. The mixtures were classified by 12 panellists in two cabins, one with white walls and the other one with black walls. These visual assessments revealed that the usage of a cabin with black walls led to better classifications of the samples as a function of their concentration.