Aspects of the kinetics and solubility of silica and calcium oxalate composites in sugar solutions

Fouling of industrial surfaces by silica and calcium oxalate can be detrimental to a number of process streams. Solution chemistry plays a large roll in the rate and type of scale formed on industrial surfaces. This study is on the kinetics and thermodynamics of SiO₂ and calcium oxalate composite formation in solutions containing Mg²⁺ ions, trans-aconitic acid and sucrose, to mimic factory sugar cane juices. The induction time (t_i) of silicic acid polymerization is found to be dependent on the sucrose concentration and SiO₂ supersaturation ratio (SS). Generalized kinetic and solubility models are developed for SiO₂ and calcium oxalate in binary systems using response surface methodology. The role of sucrose, Mg, trans-aconitic acid, a mixture of Mg and trans-aconitic acid, SiO₂ SS ratio and Ca in the formation of composites is explained using the solution properties of these species including their ability to form complexes.     

Effect of salts and sugars on the clarity of gellan gels

The effect of glucose, fructose and sucrose (0–15 wt%) on the clarity of low acyl gellan gels (0.5 wt%) in the presence of potassium chloride (40–100 mm ), calcium chloride (10–80 mm ) and their mixtures at a total molar concentration of 80 mm , was investigated by light absorbance experiments (490 nm). The effect on gel clarity (at 100 mm KCl) of all sugar combinations, at a final concentration of 15 wt%, was also investigated. All gels with potassium were less turbid than the ones with calcium. In the case of salt mixtures, increasing concentration of calcium in the mixtures resulted in decreased clarity. In addition, turbidity increased with increasing salt concentration. Moreover, and at the higher salt concentrations, the presence of sugars resulted in clearer gels. When mixtures of sugars were added, all combinations resulted in increased clarity compared to the individual sugars.     

气浮提纯新技术降低食糖中SO2残留量的研究

介绍了用气浮提纯新技术代替糖浆硫熏,可显著降低糖浆的SO2含量,混浊度、色值、钙盐、磷酸值、电导灰分和粘度均有不同程度地降低,纯度相应提高。最终可使成品糖的SO2含量和混浊度指标达到国家精制糖标准,其它指标也得到了相应的改进。     

Use of filtration and buffers in raw sugar colour measurements

Colour, an important parameter in quality evaluation of raw sugar solutions, is sensitive to and greatly affected by pH and turbidity of the solutions. Buffers and filtration were used to control the problematic colour fluctuations due to the above factors. The buffers used to maintain pH included glutaric acid, citric acid, 3-(N-morpholino)-2-hydroxy-propane sulphonic acid (MOPSO), triethanolamine (TEA) and tris-hydroxymethy-aminomethane (Tris). The turbidity was minimised by using glass-fibre filters with a 0·7-μm pore size in series. The results showed that by using MOPSO buffer and three glass-fibre filters in series, the effect of pH and turbidity on colour measurement of raw sugar solutions can be minimised. MOPSO buffer combined excellent pH stabilisation at pH 7·00 and limited colour alteration. © 1997 SCI.     

Fast detection of anionic components in sugar and wine samples using a novel device based on capillary zone electrophoresis

The quality of sugar and wine are dependent on the processing steps that are involved to remove extraneous components of starting materials, sugar canes, sugar beets and grapes. Many of the residual components present in the final product such as organic acids (malate, oxalate, formate, acetate, pyroglutamate, etc.) and inorganic ions (nitrate, nitrite, chloride, sulfate, sodium, potassium, calcium, etc.) may influence on the quality. There is a need for the development of new devices that can detect these multiple species in near-real time so that each of the processing steps can be monitored effectively. Preliminary data are presented here on the applicability of such a near real-time detection device that is based on the principles of capillary zone electrophoresis to monitor organic acid and anionic impurities in white sugar and wine samples at concentration levels that are required to meet national and international standards. Applicability of this device to monitor water pollutants is also discussed.     

亚硫酸法糖厂沉降泥汁处理之浅见

无滤布真空吸滤机产生的滤汁由于混浊而不能直接去蒸发，需要再进行净化处理。对目前糖厂处理混浊滤汁的几种常用方法作了简介，对比了各种方法的优缺点，给出了合理化建议。     

Determination of chloride, nitrate and calcium ions in sugar with ion selective-electrodes

Chloride, nitrate, and calcium ion-selective electrodes were tested and found satisfactory for the determination of the corresponding ions in highly refined white sugar, molasses and other impure sugar samples at different stages of sugar manufacturing or refining. The interferences by Br⁻ and I⁻ ions in Cl⁻ determination were eliminated by oxidation with 3 M HNO₃ and passing air to remove the free Br₂ and I₂ formed. The Cl⁻ concentration was then determined with a chloride-selective electrode against a calibration curve. Chloride should not be determined by ashing sugar, since this causes high losses of Cl⁻. It was found that NO₃⁻ and free Ca²⁺ ions could be determined directly in the sugar solution against corresponding calibration curves. Total calcium was determined after ashing of sugar samples. The ash was dissolved in 0.1 M HCl and passed through an anion exchange resin to remove PO³⁻₄ and SiO₂₋₃ ions, and Ca²⁺ was determined as before. Bound calcium was obtained by subtracting values of free from total calcium. Determination of bound calcium was useful to monitor the process of liming. For comparison, the three ions were also determined with acceptable precision without removing interfering ions using the method of standard addition and Gran's plot. The errors of determination for both direct and standard addition techniques were 3% for Cl⁻ and NO⁻₃ and 1–5% for Ca²⁺.     

红薯浊汁饮料生产工艺的研究

研究红薯浊汁饮料的生产工艺,以红心红薯为原料制作混浊汁饮料,采用色差分析和感官评价分析原料预处理方式、主要加工工艺、VC及预热方式对浊汁饮料色泽的影响;采用正交试验和感官评价确定了红薯浊汁饮料稳定剂和配方的最优水平。结果表明,分别采用预处理方式4、预热方式1和0.015%VC制作出的红薯浊汁饮料具有良好的色泽,浊汁浆液经过胶体磨后色泽变暗,之后色泽逐渐变亮;稳定剂用量为0.04%黄原胶+0.2%分子蒸馏单甘酯+0.08%海藻酸钠+0.08%CMC-Na时,浊汁饮料具有很好的组织状态和口感;配方为0.008%红薯香精,0.3%食盐,3%蔗糖,0.02%柠檬酸时,浊汁饮料具有很好的香气和滋味。     

白砂糖混浊度与钙、磷、硫含量的分析研究

亚硫酸法甘蔗制糖在糖汁提净脱色过程中添加石灰乳、磷酸、二氧化硫等,蔗汁中的有机非糖分如淀粉、胶质、蛋白质存留在白砂糖中能引起白砂糖糖液混浊。本文针对白砂糖中无机成分如钙、磷、硫的含量与白砂糖的混浊度之间的关系作了基本的分析研究。     

亚麻原麻中钙离子的测试及预处理

 为了改善亚麻现行的初加工方法,对亚麻原麻中的钙离子含量进行了研究与测试。结果表明,亚麻中97%以上的钙离子都位于果胶中,这些钙离子对脱胶有很大的影响。选用EDTA、多聚磷酸钠、草酸和草酸铵等螯合剂对亚麻原麻进行了预处理,结果表明：EDTA、草酸、多聚磷酸钠的处理效果均不理想,改变浓度、温度等条件,韧皮与麻秆并没有分离。而草酸铵是比较有效的螯合剂,用 5g/L的草酸铵在62℃处理亚麻原麻5h后,韧皮与麻秆能够完全分离。     

Ingredients and pH are Key to Clear Beverages that Contain Whey Protein

ABSTRACT:  A challenge of shelf stable beverages that contain whey protein is that a small portion of protein can be denatured and aggregated during thermal processing, resulting in a turbid solution or white precipitate that consumers perceive as a defect. In this study, 3 approaches were taken to reduce turbidity in heat-treated beverages that contain whey protein: (1) centrifugation to remove insoluble protein aggregates, (2) addition of ingredients, and (3) alteration of pH in the range from 3.0 to 4.0. At pH 3.6 and below, all samples were essentially clear both before and after heating for all ingredients. At a pH of 3.8 and above, ingredient selection was crucial to solution clarity after heat treatment. At a pH of 4.0, addition of salts at both 10 and 50 mM increased the turbidity significantly compared to the control, which contained only whey protein in water. Neither addition of sugars at 25, 50, and 100 g/L, nor addition of sugar alcohols at 25 g/L significantly affected turbidity after heat treatment compared to the control. However, sugar alcohols added at 50 or 100 g/L significantly reduced turbidity after heat treatment compared to the control. Removal of insoluble protein aggregates by centrifugation prior to heat treatment resulted in a statistically significant decrease in turbidity after heat treatment. Understanding these results at the molecular level will assist food scientists in selecting processing treatments, ingredients, and pH in the development of shelf stable clear beverages that contain whey protein.     

响应面法优化罗非鱼鳞钙结合肽酶解工艺及其特性表征

为研究罗非鱼鳞钙结合肽酶解制备最佳工艺条件及其螯合特性,从而为促钙吸收活性物质的研究提供基础,本研究以脱钙罗非鱼鳞为原料,钙螯合活性为指标,选用木瓜蛋白酶对罗非鱼鳞酶解工艺进行优化,获得罗非鱼鳞钙结合肽,并通过氨基酸分析、紫外光谱和红外光谱表征肽钙螯合特性。结果表明,罗非鱼鳞钙结合肽的最优酶解条件为底物浓度8%、时间2 h、酶底比0.3%、pH7、温度60 ℃,在此条件下酶解物钙螯合活性为(38.31±0.4) μg/mL。表征结果表明,螯合钙离子后,肽钙螯合物中天冬氨酸、谷氨酸、甘氨酸、赖氨酸、丝氨酸、半胱氨酸及组氨酸的含量分别增加了0.88%、1.48%、0.34%、0.53%、0.04%、0.38%、0.46%。钙结合肽中的羧基氧和氨基氮等基团参与了与钙离子的结合,形成了罗非鱼鳞肽钙螯合物。罗非鱼鳞钙结合肽具有较高的钙螯合活性,这为补钙剂的生产应用奠定了基础。     

Non-pollen particulates in honey and sugar

A total of 19 honey samples, mostly from Germany but also from France, Italy, Spain and Mexico, were analysed for non-pollen particulates. Only coloured fibres and fragments were quantified. Transparent fibres, considered to be cellulosic because they could be stained with fuchsin, were not quantified. Coloured material was found in all the samples investigated. Fibre counts ranged from 40/kg to 660/kg of honey, with a mean value of 166 ± 147/kg of honey, whereas fragments were considerably less abundant (0–38/kg of honey; mean 9 ± 9/kg of honey). Sources are tentatively identified as environmental, that is particles having been transported by the bees into the hive, or having been introduced during honey processing or both. In addition, five commercial sugars were analysed. In all the refined samples, transparent and coloured fibres (mean 217 ± 123/kg of sugar) and fragments (32 ± 7/kg of sugar) were found. Unrefined cane sugar had 560 fibres and 540 fragments per kilogram of honey. In addition, in both honey and sugar samples, granular non-pollen material was observed.     

补钙面条加工技术研究

对添加胶原多肽螯合钙的补钙面条加工技术进行了研究。以猪皮明胶为原料,制备胶原多肽螯合钙,并对其结构进行了表征。添加胶原多肽螯合钙、猪皮明胶、复合磷酸盐和食盐对面条品质进行改良,通过感官评价对补钙面条的加工条件进行优化。试验结果表明,补钙面条的最佳配方为:胶原多肽螯合钙添加量为2%,猪皮明胶添加量为1.5%,复合磷酸盐添加量为0.8%,食盐添加量为1.5%,小麦粉94%。面条产品弯曲断条率为0,熟断条率为0,干物质失落率为6.9%,蒸煮吸水率为167.5%,面汤浊度为0.104。经感官评价,面条得分为88.7分。通过添加胶原多肽螯合钙,补钙面条中强化钙量为143.6 mg/100 g。补钙面条外观色泽良好,风味较好,食用营养价值高。     

Roles of reversible and irreversible aggregation in sugar processing

Colloids (1–1000-nm particles) in sugarcane/beet juice originate from non-sucrose impurities (polyphenolic colorants, residual soil, polysaccharides) of the plant materials; additional colloids form during the high temperature processing. Colloids are reactive toward aggregation, sorption, desorption, and redox/hydrolysis/thermal transformation reactions. Both Derjaguin–Landau–Verwey–Overbeek (DLVO; van der Waals and electrostatic forces) and non-DLVO (involving hydrophilic colloids) interactions control the stability of colloids in juice. Heteroaggregation causes a range of feedstock and end product problems, including turbidity, viscosity, color, gelling, crystallization, starch ghost, and heat transfer problems. Even after intensive clarification and refining, trace colloidal impurities on white (refined) sugar remain to cause a problem known as acid beverage floc. Acid beverage floc is an example of DLVO-type aggregation of oppositely charged particles at decreased pH. Examples of irreversible aggregates include starch ghost and recalcitrant organomineral composites formed at elevated temperature that resist heat transfer. Fundamental knowledge in aggregation kinetics is necessary to predict the occurrence of undesirable aggregates, as pH, ionic strength, temperature, and sucrose concentration change during the processing of sugarcane/beet juice.     

啤酒中浑浊物质的鉴定

该研究意在建立啤酒浑浊物质鉴定方法体系。试验中采用直接镜检法、染色镜检法、酸碱溶解法、酶解法、理化分析法对悬浮型浑浊、大颗粒浑浊、雾状浑浊这3种不同类型的啤酒浑浊进行了鉴定。经过实践检验,悬浮型的浑浊物质,可以采用直接镜检法和染色镜检法进行鉴定。大颗粒的浑浊物质可以采用直接镜检法、酸碱溶解法、理化分析法进行鉴定。雾状浑浊物质可采用直接镜检法,酶解法对其进行鉴定。上述鉴定方法体系能区分绝大部分啤酒浑浊物质。     

酱油澄清及浊度的测定

酱油是一种发酵食品，生产中会出现浑浊现象，需要进行澄清。对酱油的澄清程度仅有感官要求，缺少量化方法。本文采用一种15度前散射光的浊度计，使用卤素灯作为光源，内置了独特的光学系统及散射透过比率式的计算程序，以15度前置散射光直接检出方式，因此不受酱油颜色的影响，线形关系强，还可以直接显示数据，样液中颗粒直径对测定值的影响较小，十分适合酱油浊度测定。     

Structure and properties of sugar beet fibres

Fibrous fractions were prepared from sugar beet pulp (RF) by sequential extractions with potassium oxalate, 0.05 M hydrochloric acid at 85°C and 0.05 m sodium hydroxide at 4°C. The overall composition, polysaccharide structure and some physico-chemical properties (cation exchange capacity, CEC; water holding capacity, WHC; swelling) of each fraction were determined. RF was mostly composed of carbohydrates (66.3 %) with minor amounts of ash, proteins and lignin. The main polysaccharides were highly methylated and acetylated pectins, cellulose and arabinans. The oxalate residue (82.1 % of RF) exhibited only minute differences from RF whereas the acidic and alkaline residues, accounting for 42.8 % and 35.5 % of RF, respectively, were enriched in cellulose and hemicelluloses (xylans, xyloglucans, mannans) and mostly devoid of pectins and arabinans. CEC and WHC of fractions were closely related to the content of unmethylated galacturonic acid residues. The influence of the ionic form of ionisable groups was demonstrated, the Na⁺ form giving the highest WHC. The ionic strength of the medium can reduce the WHC, especially in the case of the acid and alkali-extracted fibres.     

Investigation of mechanisms of oxidation of EDTA and NTA by permanganate at high pH

Permanganate has been used for oxidation of nuclear wastes containing chelating agents such as ethylenediaminetetraacetic and nitrilotriacetic acids (EDTA and NTA) to improve separation of radionuclides and heavy metals from the wastes, butthe mechanisms of degradation of these and related organic ligands at high pHs have not been studied. EDTA, NTA, and the model compound ethylenediamine (EN) were found to be readily oxidized by permanganate at pH 12-14. The reduction of permangante was accompanied by formation of unstable manganate and dispersed MnO2 particles, which constituted the final product of permanganate reduction. The yields and speciation of EDTA, NTA, and EN breakdown products were affected by the pH and permanganate dose. Iminodiacetic acid (IDA), oxalate, formate, and ammonia were the predominant EDTA and NTA oxidation products. Mineralization of EDTA, NTA, and EN to CO2 was more significant at pH 12. At pH 14 formation of oxalate and deamination to NH3 were the most important reactions. IDA was released upon the oxidation of both EDTA and NTA, but EDTA oxidation yielded no ethylenediaminediacetic acid (EDDA). The speciation of the reaction products indicated that the ethylene group in EDTA was the preferred attack site in oxidations by alkaline permanganate.     

Fenton oxidation products derived from hydroxycinnamic acids increases phenolic‐based compounds and organic acid formation in sugar processing

The hydroxycinnamic acids (HCAs), caffeic acid (CaA), p‐coumaric acid (pCoA) and ferulic acid (FeA) are the main phenolic acid colour precursors present in sugar cane juice. The Fenton oxidative degradation products of these HCAs and mixture using Fe²⁺/H₂O₂ at pH 4.72 at 25 °C were identified using chromatography and mass spectrometry techniques. Oxalic (≤14 wt%), isobutyric (≤13.5 wt%) and formic acids (≤1.3 wt%) were the main organic acids formed. CaA produced the highest proportion of oxalic and isobutyric acids, while FeA produced the highest proportion of formic acid. The presence of increased proportion of oxalic acid in juice will increase the proportion of calcium oxalate scale in sugar mill heat exchangers. The phenolic‐based products identified include protocatechuic aldehyde and 4‐hydroxybenzoic acid and the basic phenols, p‐allyphenol, p‐vinylguaiacol, trans‐isoeugenol, which when present in juice may react with juice constituents to increase juice colour in subsequent processing.