Strawberry juice colour: A study of the quantitative and qualitative pigment composition of juices from 39 genotypes

The juices from 39 strawberry genotypes were analysed for anthocyanin composition and colour characteristics. No single cultivar or breeding line possessed the innate pigment characteristics thought to confer greater colour stability on strawberry juices but the anthocyanin patterns were far more complex than hitherto reported in strawberries. Thirteen different peaks were observed during high-performance liquid chromatography of the juices and tentative identifications are proposed for two previously unidentified strawberry anthocyanins. The occurrence of pelargonidin 3-rutinoside was confirmed. Colour quality measurements derived from CIELAB L*a*b* values are reported for the fresh juices.     

草莓色素稳定性研究

本文以提纯的草莓色素为材料，研究了光照、ｐＨ值、温度等因素对其稳定性的影响，结果表明溶液酸度不仅对色素的吸收光谱有显著影响，而且对其稳定性也有一定影响。光照和加热都可以加快色素的降解，这种降解反应符合化学动力学一级反应规律，可用反应速率常数计算不同条件下产品中的色素含量。     

兔眼蓝莓花青素稳定性研究

研究了杰兔兔眼蓝莓花青素提取液的稳定性。研究结果表明:pH、日光和自然光均显著影响蓝莓花青素稳定性,但Na+对蓝莓花青素稳定性影响不显著。苯甲酸钠、浓度高于1.2mmol/L的Zn2+、浓度高于12mmol/L的Cu2+和Ca2+、浓度高于10%的蔗糖和葡萄糖有改善蓝莓花青素稳定性效果;而Fe3+、Fe2+、氧化还原剂、VC、低浓度的蔗糖、果糖有微弱降低蓝莓花青素稳定性的效果。在杰兔·兔眼蓝莓加工和贮藏过程中需要注意避免光照,pH,Fe3+、Fe2+、VC、低浓度的蔗糖和果糖产生的不利影响。      

食用玫瑰花色苷的提取及其稳定性研究

以吸光值为指标得出了食用玫瑰花花色苷提取的最佳条件:10%的柠檬酸溶液为浸提液,料液比1:10,50℃提取1.5h。对花色苷粗提物的稳定性研究表明,玫瑰花色苷对溶液pH敏感,随着pH的升高,最大吸收波长红移,颜色由红色逐渐变为灰色;热稳定性较好;光照、Mg2+、VC、氧化剂及还原剂能够破坏花色苷的结构,使其降解;Cu2+、Al3+、Ca2+、Na+及蔗糖可能与色素发生辅色效应从而明显地提高了其稳定性;K+、Zn2+、Fe2+及葡萄糖则没有显著的影响。     

花色苷的热稳定性及其影响因素研究

花色苷是优良的天然植物源色素,同时具备抗氧化、抗肿瘤等重要生理功能。花色苷的热稳定性是影响其在食品工业中应用的主要因素,本文对花色苷的热降解动力学和热降解影响因素进行了综述。花色苷在食品中的热降解动力学均为一级动力学,影响其降解的主要因素包括pH、压强、温度、糖类、黄酮类物质、抗坏血酸类及其自身的酰基化程度。     

黄酮对刺葡萄花色苷辅色稳定化效果的研究

研究了几种黄酮类物质对刺葡萄花色苷的辅色作用,并研究了槲皮素、黄芩素和芦丁对刺葡萄花色苷热稳定性的影响。结果表明:槲皮素对刺葡萄花色苷的辅色效果最为显著（p<0.05）,其次是黄芩素和芦丁,浓度为0.1 mmol·L-1时单位浓度辅色效果最佳;槲皮素和黄芩素辅色时,在p H2.0处,辅色效果最好,而芦丁辅色时,最佳p H为3.0。加入槲皮素、黄芩素、芦丁后,刺葡萄花色苷的降解速率常数（k）皆显著小于对照组,半衰期（t1/2）均显著高于对照组（p<0.05）。经槲皮素、黄芩素、芦丁辅色后刺葡萄花色苷的活化能（Ea）分别为88.48、91.67、83.62 k J/mol,显著（p<0.05）高于对照组的74.51 k J/mol,说明加入槲皮素、黄芩素、芦丁能提高刺葡萄花色苷的热稳定性。      

树莓花色苷稳定性的研究

以红树莓花色苷为研究对象,系统研究了光照、温度、pH、食品添加剂和金属离子对树莓花色苷稳定性的影响。结果表明,随加热温度的升高花色苷稳定性下降,在60℃以下花色苷稳定;室外自然光照花色苷不稳定,避光条件下稳定性良好;在pH1.0和pH3.0时花色苷稳定,pH5.0、7.0、9.0花色苷不稳定。食品添加剂苯甲酸钠和蔗糖使花色苷稳定性增加,抗坏血酸使花色苷稳定性降低。金属Al3+离子对花色苷具有增色效应,Al3+和Ca2+对花色苷稳定性无影响。      

不同品种蓝莓花色苷稳定性的比较研究

本实验探讨了p H、热、光、金属离子（Na+、Ca2+、Fe3+、Mg2+、Cu2+、Zn2+）、H2O2、Na2SO3、蔗糖、苯甲酸钠、D-异抗坏血酸钠以及不同包装材质对两种蓝莓花色苷理化稳定性的影响。结果表明:蓝莓花色苷只有在酸性条件下才可稳定存在;对热、光敏感,稳定性差;氧化剂及还原剂对蓝莓花色苷有较大的破坏作用,蔗糖却有明显的增色作用;PET材质更适合做为蓝莓产品的包装材料。由两种蓝莓比较得出低丛蓝莓花色苷的理化性质更为稳定,在今后的加工或是色素提取中应该选用花色苷性质相对稳定的蓝莓品种。      

紫苏叶花色苷稳定性的研究

紫苏是我国传统的药食两用植物,因含有丰富的花色苷成分,具有广阔的产业发展前景。随着人们对天然色素日益增长的需求,紫苏叶花色苷将成为一个良好的天然色素来源。本文研究了pH、光照、温度等因素对紫苏叶花色苷稳定性的影响:紫苏叶花色苷不耐高温,在光照条件下比较稳定,然而长时间的光照也会对紫苏叶花色苷造成影响。pH对其影响显著,在pH2⁴范围内相对稳定。大部分无色金属离子对紫苏叶花色苷的稳定性没有影响,而Cu2+、Fe3+对紫苏叶花色苷稳定性影响较大。除此之外,氧化还原剂、苯甲酸钠和VC对紫苏叶花色苷都有破坏作用。      

Interaction of mulberry anthocyanins with soybean protein isolate: effect on the stability of anthocyanins and protein in vitro digestion characteristics

The interactions of anthocyanins and proteins might mutually influence each other on the physicochemical and functional properties. In this study, the interaction mechanism of soybean protein isolate (SPI) with mulberry anthocyanins (MA), and its effect on the thermal stability of anthocyanins and protein subunits’ digestibility were investigated through multiple spectroscopies and in vitro gastrointestinal models. Results showed that cyanidin-3-O-glucoside (C3G), the main anthocyanin monomer in MA, could bind to SPI through hydrophobic interactions, resulting in static fluorescence quenching of SPI. The secondary structure of SPI changed by binding to C3G, with an increase of β-sheet and a decrease of α-helix and random coil. The formation of the SPI-MA complexes improved the thermal stability of MA at 353 K, while, no significant protection occurred during heating at 368 K. Complexation with MA promoted the digestibility of SPI by pepsin, especially the α′ and α subunits of β-conglycinin and the basic subunit of glycinin, and slightly delayed the digestibility of SPI under intestinal fluid. These results provide an in-depth understanding of the influence of the protein-anthocyanin interactions on the stability of anthocyanins and protein digestibility.     

甘蔗皮花色苷的提取工艺及稳定性初探

通过单因素实验和正交实验对甘蔗皮花色苷的提取工艺进行优化,并对其稳定性作初步探讨。结果表明：用80%乙醇-盐酸溶液（pH=1.0）作为提取剂,料液比1∶20（g/mL）,40℃恒温超声波（超声功率100W）辅助提取2.0h,提取效果最佳,花色苷含量达到288.06mg/100g。稳定性实验表明,甘蔗皮花色苷溶液对pH、光照、温度等敏感,对钠、钾、钙、镁、铜等金属离子均稳定,但铁离子会使其变质。     

加工工艺对蓝莓汁和蓝莓酒中花色苷及类黄酮的影响

为了优化保留蓝莓中活性成分的加工工艺参数,考察了制汁、不同发酵工艺条件对蓝莓汁和蓝莓酒中花色苷和类黄酮物质的影响。结果表明,添加3‰果浆酶在60 ℃条件酶解2.0 h制得的蓝莓汁出汁率提高至72.50%,可溶性固形物含量为14.5%,花色苷及类黄酮含量分别为250.36 mg/100 mL和408.10 mg/100 mL。选择蓝莓原果浆在接菌量4%、25 ℃的条件下不加糖发酵的蓝莓酒花色苷及类黄酮含量分别为111.50 mg/100 mL和523.87 mg/100 mL。研究结果为提升蓝莓汁及蓝莓酒的营养品质提供一定的理论依据。     

天然色素花青素的微胶囊化研究

研究喷雾干燥法制备高包埋率微胶囊化花青素的壁材组成以及工艺条件,结果表明:花青素∶壁材为20%、麦芽糊精∶β-环状糊精为3∶1、阿拉伯胶比例为10.0%、喷雾干燥的进口温度120℃、出口温度80℃时,花青素的微胶囊化效果最好、包埋率高,而且花青素微胶囊化后,其稳定性有显著提高。     

Effects of pre‐freezing,puree content and pasteurisation regime on colour stability of strawberry nectar made from puree

BACKGROUND: Heat treatment during processing of strawberry products has been proposed to negatively affect colour stability. Moreover, the role of enzymes with respect to colour stability is ambiguous when consulting the existing literature. The aim of the present study was to investigate the impact of various processing parameters (pre‐freezing, puree content, pasteurisation temperature and heating time) on the colour stability and anthocyanin monomer and L ‐ascorbic acid contents of strawberry nectars made from puree. In addition, the effect of different enzyme activities on colour stability during storage of strawberry nectars was investigated. RESULTS: Pre‐freezing of strawberries before processing had a significant positive effect on the colour stability of nectars made from puree. No significant effect on colour stability was found for higher puree contents. Increasing both the pasteurisation temperature and the heating time had a significant positive effect on colour stability. Results showed that colour degradation during storage was mainly due to residual enzyme activities. The shelf‐life of strawberry nectar could be extended about fivefold by adding an enzyme inhibitor. CONCLUSION: The colour stability of strawberry nectar made from fresh puree may be improved to some extent by an appropriate pasteurisation regime. Enzymes play an important role in colour degradation during storage of the nectar. Inactivation of these enzyme activities, however, could not be achieved even after a heat treatment at 90 °C for 60 min. Copyright © 2008 Society of Chemical Industry     

Thermal Inactivation of Escherichia coli O157:H7 in Strawberry Puree and Its Effect on Anthocyanins and Color

Raw whole strawberries, if contaminated with pathogens, such as Escherichia coli O157:H7, must be pasteurized prior to consumption. Therefore, the objective of this research was to investigate the thermal inactivation kinetics of E. coli O157:H7 in strawberry puree (SP), and evaluate the changes in anthocyanins and color, and the survival of yeasts and molds (YM) after thermal processing. Inoculated with a 5‐strain cocktail, fresh SP, with or without added sugar (20 and 40 °Brix), was heated at 50, 52, 54, 57.5, 60, and 62.5 °C to determine the thermal resistance of E. coli O157:H7. In raw SP, the average D‐values of E. coli O157:H7 were 909.1, 454.6, 212.8, 46.1, and 20.2 s at 50, 52, 54, 57.5, and 60 °C, respectively, with a z‐value of 5.9 °C. While linearly decreasing with temperature, the log D‐values of E. coli O157:H7 increased slightly with sugar concentration. The log degradation rates of anthocyanins increased linearly with temperature, but decreased slightly with sugar concentrations. These results suggest that sugar may provide some protection to both E. coli O157: H7 and anthocyanins in SP. The browning index was not affected by heating at 50 and 52 ºC at low sugar concentrations, but increased by an average of 1.28%, 2.21%, and 10.1% per min when SP was exposed to heating at 54, 57.5, and 60 °C, respectively. YM was also inactivated by heating. This study demonstrated that properly designed thermal processes can effectively inactivate E. coli O157:H7 and YM in contaminated SP, while minimizing the changes in anthocyanins and color.     

酰基化蓝莓花色苷的稳定性和对氧自由基清除能力

由于天然花色苷稳定性差,严重阻碍了其在食品工业中的广泛应用。为了改善花色苷的稳定性,采用分子修饰的方法,通过酰基化反应修饰蓝莓花色苷,并研究酰化后蓝莓花色苷的光、热稳定性和对氧自由基的清除能力。通过紫外吸收光谱和红外光谱表明蓝莓花色苷已经酰基化。相对未酰化的蓝莓花色苷,酰基化蓝莓花色苷的光、热稳定性显著提高,但清除羟基自由基、超氧阴离子自由基的能力略有下降,清除羟自由基、超氧阴离子自由基的IC50分别为0.74、3.14mg/mL。     

The effect of some processing variables on non-coloured phenolic compounds in port wines

 The non-coloured phenolic fraction of fortified port wines was studied. Trials using several mash-extraction techniques which may be used during port wine making were evaluated for their effectiveness by measuring qualitative and quantitative differences in phenolics. Total phenolic compounds measured by spectrophotometry and HPLC analysis were compared, and the greater values obtained using spectrophotometry are attributable to the contribution of anthocyanins and non-phenolic UV-absorbing compounds. Quantitative and qualitative differences in composition were observed depending on the extraction mode. The greatest total phenolic content was found in port wine made by traditional foot treading, while early addition of extra alcohol to the mash had a neutral or negative effect on the yield of phenolic compounds. Received: 20 March 1997     

黑米花青素的浸提工艺优化及稳定性研究

该文对黑米花青素的提取工艺进行优化,在单因素试验的基础上,以浸提时间、料液比、提取温度为自变量,通过正交试验得到浸提黑米花青素的最佳工艺条件为乙醇、乙酸乙酯混合溶液1∶1（V/V）,提取时间90 min,提取温度80 ℃,料液比1∶6（g∶mL）。在此工艺条件下,黑米花青素吸光度值为3.761。进一步研究不同温度、光照、氧化剂等贮藏条件对黑米中花青素稳定性的影响。结果表明,黑米花青素在≤80 ℃的环境中存放具有一定的稳定性;日光对黑米花青素的稳定性有很大影响,应避光保存;氧化剂对花青素有明显的破坏作用,其体积越大,破坏作用越大。     

复合花青素饮料的制备及提高其稳定性的方法

本实验将以葡萄皮、黑米、紫甘薯提取物为原料的复合花青素应用于果味饮料中,通过选择最适辅色剂种类并确定添加量,提高了花青素在酸性饮料体系中的保存率。通过正交实验确定饮料的最佳配方为:柠檬酸0.16%,果葡糖浆10%,蓝莓香精0.06%,复合花青素0.1%;结合杀菌条件选择茶多酚作为最适辅色剂,添加量为500 mg/kg时效果最佳,饮料颜色在杀菌条件下的保存率可达90.9%。实验中的饮料产品在低温下贮存时间更长,其中在4℃时饮料中花色苷的贮存期为230 d左右。