Effect of Equilibrium Water Activity on the Bulk Properties of Selected Food Powders

The bulk properties of powdered coffee creamer, infant formula, salt and sucrose at different levels of water activity were characterized by mechanical methods. These included loose bulk density, compressibility, cohesion, % irrecoverable work in compression and asymptotic modulus after stress relaxation. In the crystalline powders the physical characteristics generally followed the pattern established by the moisture content with an apparent critical water activity beyond which changes became drastic. In the creamer and formula which were very cohesive even in the dry form, the changes in bulk properties were generally more gradual. The rheological tests indicated that much of the physical changes in the salt and sucrose powders could be attributed to surface moisture. In the creamer and formula the plasticity of the particles material was also a major factor that affected the bulk behavior.     

Flow Properties of Spray-Dried Encapsulated Butteroil

The interdependence of physical properties of spray-dried butteroil encapsulated in sucrose, lactose or all-purpose flour were evaluated and compared to those of common powders such as spray-dried nonfat dry milk, whole milk powder, and sodium chloride. Powders were evaluated in terms of flow (mass flow rate and angle of repose), bulk (density) and mechanical properties (compressibility and stress relaxation). The powders were classified into three groups by mechanical sieving based on size as: “small particles” (>210 μm), “particles” (+210–420 μm) and “encapsulated particles” (+210–500 μm). The flow and mechanical behavior of encapsulated powders were different (P < 0.05) from the other powders. Encapsulated powders were less flowable (P < 0.05) but the addition of 2% anti-caking/flow agent enhanced flow characteristics.     

Migration of Absorbed Food Colorants Between Powder Components

Granular sucrose, malic acid and cornstarch were colored with FD&C Yellow No. 5 and Blue No. 1. The pure and colored powders, each species having a different particle size, were mixed together in combinations where the colored ingredients in the mixture carried a different colorant and were subsequently sieved to retrieve the original carrier particles. The color of the retrieved powders indicated that the colorant particles were redistributed between the carrier's particles through migration and reabsorbtion.     

斑点叉尾鮰鱼骨脱脂及其制备CMC 活性钙的工艺优化

以斑点叉尾鮰鱼骨为实验材料,对脱脂鮰鱼骨粉制备工艺,脱脂骨粉在不同的温度、时间、柠檬酸和苹果酸的酸比例、酸质量浓度、骨粉粒度条件下转化成活性钙的效果进行研究。结果表明,鮰鱼骨脱脂的最佳工艺方案为5g/100mL NaOH 溶液浸泡6h,脱脂后的鱼骨粉总钙含量为30.38%。实验采用柠檬酸和苹果酸活化脱脂鮰鱼骨粉制取CMC 活性钙,其最佳工艺条件为柠檬酸和苹果酸的比例1:2、酸质量浓度15g/100mL、骨粉粒度120目、温度100℃、提取时间60min。此时,钙提取率可达87.13%。     

Effect of Four Anticaking Agents on the Bulk Characteristics of Ground Sugar

Fine silicon oxide, sodium aluminum silcate, tricalcium phosphate and calcium stearate powders were admixed with dry ground sugar at four concentration levels between 0.1 to 2%. Appreciable increase in loose bulk density and decrease in compressibility were noticeable at 0.1% concentration in all four agents. The effect reached an apparent peak or a flat maximum at an agent concentration of about 0.5–1%. With the exception of silicon oxide treated powders, increase in density was accompanied by a corresponding decrease in compressibility. Bulk parameters (i.e., density and compressibility) were more sensitive indices to changes occurring in powders as compared to parameters determined in compacted specimens (i.e., yield in shear, internal friction and relaxation pattern). Results are explained in terms of possible bed arrays and their scatter by differences in particle size and shape distributions. Support for these explanations is presented in scanning electron micrographs of sugar treated and untreated particles.     

Organic acids of various kinds of vegetables. IV. Changes in the acids and sugar in tomatoes, sweet peppers and cucumbers during development and ripening

Concentrations of organic acids and sugars in tomatoes and sweet peppers change notably during ripening. The concentration of malic acid decreases while that of citric acid increases considerably and in redripe fruits clearly exceeds the content of malic acid. Several maxima and minima in acid concentrations occur during development. Both species show constant proportions of citric and isocitric acid (200:1 and 30:1 respectively). In sweet pepper, quinic and ascorbic acid can be found in noticeably higher amounts than in tomatoes. Additionally, succinic acid was detected in tomatoes and fumaric and shikimic acid in sweet pepper. Glucose and fructose, in approximately equal amounts, are the main sugar components; their concentrations are increased during ripening, especially in sweet peppers. The leaves of tomatoes and sweet pepper contain more malic acid and less citric acid than redripe fruits, though here as well citric acid predominates. There is considerably less glucose and fructose present in the leaves of sweet pepper than in the fruits while sucrose is increased. Sucrose is the main sugar component in the leaves. Compared to tomatoes and sweet peppers, egg-plants contain more amounts. - Potatoes contain citric, malic, quinic, succinic, fumaric, and soluble oxalic acid (in order of decreasing amounts). - In cucumbers malic acid notably exceeds citric acid. Both acids hardly change in concentration during ripening. Sugar content decreases during ripening.     

卷烟中非挥发性有机酸、糖类、某些氨基酸和磷酸的同时测定

以山梨醇作内标,羟胺吡啶和BSTFA 1%TMCS为衍生化剂,采用GC法同时测定了国内外21种牌号卷烟中的木糖、阿拉伯糖、鼠李糖、果糖、甘露糖、半乳糖、葡萄糖、蔗糖、麦芽糖、天门冬氨酸、天门冬酰胺、丙二醇、丙三醇、乳酸、丙二酸、苹果酸、柠檬酸和磷酸。结果显示:①丙二醇和阿拉伯糖的RSD>10%,乳酸、天门冬酰胺、鼠李糖、半乳糖和麦芽糖的RSD>5%,其它成分的RSD<5%;②除丙二酸、半乳糖、鼠李糖、丙三醇和阿拉伯糖的回收率介于70%~75%外,其它组分的回收率>80%;③在所分析的卷烟样品中,进口混合型卷烟中柠檬酸、天门冬氨酸、天门冬酰胺、丙二醇和丙三醇含量较国产烤烟型卷烟的高,而糖类的含量则普遍较低,其它成分差别不大。     

Authentication of pomegranate juice using multidimensional analysis of its metabolites

With the growing popularity and demand of pomegranate juice, its adulteration has also steadily increased. In this study, to authenticate pure or adulterated juice, the major components of pomegranate juice were compared with those of grape, peach, and apple juices (which are common adulterants in pomegranate juice) using liquid chromatography–electrospray–tandem mass spectrometry, ion chromatography, and inductively coupled plasma spectrometry. The various parameters evaluated were as follows: the ratio of malic acid to citric acid content, presence of tartaric acid, and levels of glucose, fructose, and mannitol, and sucrose. Potassium was the most abundant mineral in pomegranate juice, and the content ratio of other minerals/potassium did not exceed 0.1. The reliability of this method was confirmed in blind tests and monitoring experiments with commercial pomegranate juice. In conclusion, a simple and effective method was developed to detect adulteration in pomegranate juice.

     

An investigation on dielectric properties of major constituents of grape must using electrochemical impedance spectroscopy

The Australian wine industry has been undergoing an unprecedented growth during the last decade in both winery establishments and export volumes. Though automated controlling processes are useful for maintaining high quality products and reducing costs, the techniques are not widely adopted by small to medium sized wineries due to their relative high initial costs. In this paper, we investigate the dielectric properties of ethanol and organic acids, two major chemical ingredients that need to be monitored during wine fermentation using electrochemical impedance spectroscopy. The relationships between solution concentrations and parameters derived from the measured impedance spectra were investigated by two methods, the Nyquist plot approach and the equivalent circuit modeling approach. The investigation was carried out for both pure solutions including ethanol, malic acid and tartaric acid, the major constituents of grape must, and their various mixed compound solutions to simulate the grape must under fermentation. Strong linear as well as inverse-squared relations were found between the concentrations of the pure solutions and the derived dielectric parameters, e.g., the diameter of the Nyquist plot for ethanol has a correlation with concentrations with a coefficient of determination of 0.9796 and the R _s value obtained from electric circuit modeling also shows a strong inverse-squared relationship with the concentration of both malic and tartaric acids. A further investigation suggests that the individual concentration of mixed acid solutions can be handily determined by measuring the impedance of the mixed acid solutions and using the initial concentration value of one of the mixed acids. Furthermore, the dielectric properties of mixed ethanol, malic acid and tartaric acid show a combined effort from mixed acid solutions and pure ethanol. These findings suggest that the electrochemical impedance, which can be easily measured with satisfactory accuracy, is a good indicator of the concentration change of the essential ingredients of grape must and thus can be further utilized to develop a feedback loop for wine fermentation automatic control.     

有机酸味剂对低钠盐增咸作用的研究

以1.0%(w/w)的氯化钠溶液为标准参照,重点研究了L-苹果酸、琥珀酸、柠檬酸、富马酸等有机酸味剂与低钠盐的复配效果。通过品尝小组对复配溶液的咸度、酸度等进行感官评定,结果表明:当单独添加L-苹果酸、琥珀酸、柠檬酸、富马酸的量依次分别为1.6%、0.8%、2.4%、0.8%(w/w)时,对低钠盐有明显的掩盖苦味及增咸效果,其中添加1.6%L-苹果酸的复配溶液咸味纯正,综合口感良好,增咸效果可达1.33倍。     

Malolactic fermentation in sea buckthorn (Hippophaë rhamnoides L.) juice processing

Malolactic fermentation (MLF) traditionally used in winemaking was applied to sea buckthorn to reduce the high sourness of the berry juice. Chemical and microbiological aspects, as well as sensory properties of the juice during MLF were studied in order to develop an optimal process. In 1:1 water diluted juice with malic acid content of 15 g/l and pH 2.8, efficient conversion of l-malic acid to l-lactic acid was achieved with direct inoculation of unadapted Oenococcus oeni at a cell density of 10⁹ CFU/ml. The rapid malic acid degradation was performed by non-growing bacterial cells without loss of sugars, vitamin C, or pulp oil. More than 50% of the initial malic acid was metabolized to lactic acid and CO₂ already in 12 h of fermentation and a significant decrease in sourness and astringency was noticed. In 24 h fermentation, pH value was increased to 3.1 and only 3 g/l malic acid remained in the juice. Prolonged fermentation had only minor effect on malolactic reaction, but off-flavor of the juice began to increase.     

初烤烟叶25种化学成分与焦油的相关、逐步回归及通径分析

测定了182份初烤烟叶样品的烟气焦油量和25种烟叶化学成分,建立了初烤烟叶化学成分与烟气焦油的多元逐步回归方程,并采用相关分析、逐步回归分析和通径分析等方法分析了焦油含量与烟叶化学成分的相关关系。结果表明:①总糖、钾、水分、纤维素、丁二酸、苹果酸、棕榈酸、油酸、亚麻酸、硬脂酸与焦油呈极显著的负相关,总氮、烟碱、挥发碱、蛋白质、芸香苷、丙二酸与焦油呈极显著正相关。②丙二酸、硬脂酸、总糖、烟碱、钾和苹果酸为影响焦油的重要指标;丙二酸、硬脂酸、总糖与焦油的相关是由直接作用和间接作用共同影响的,但直接作用的影响要大于间接作用;烟碱、苹果酸、钾与焦油的相关主要取决于直接作用。     

Evaporation of a model skin lotion with beta-hydroxy acids

Two beta-hydroxy acids, malic and salicylic acids were combined with a non-ionic surfactant, a commercial pentaoxyethylene sorbitan mono-oleate and water to form a simple model of a skin lotion and the phase diagrams were determined. One emulsion formulation with relative amounts of the three components similar to those in commercial lotions was used to observe microscopically the changes in the emulsion structure during evaporation. The microscope images were subsequently compared to the information from the phase diagram under equilibrium conditions. The results showed the behavior of the systems of the two acids to be distinctly different; as exemplified by that of a typical formulation with 3% by weight of acid and 5% of surfactant. The malic acid system consisted of vesicles, exclusively formed by the surfactant and water, in an aqueous molecular solution of the acid and the initial evaporation resulted in an increase of the acid concentration in the aqueous solution to reach 35.5%, before solid crystals of the acid solid solution appeared. The salicylic acid formulation, on the other hand, already at the beginning of the determination consisted of water, particles of the acid solid solution and surfactant vesicles. In both cases the remaining deposit after total evaporation was particles of a solid acid solution and liquid surfactant.     

连平鹰嘴桃矿物元素及糖酸组分与糖酸比的灰色关联分析

目的 研究连平鹰嘴桃种质资源的品质,积累相关数据。方法 采集鹰嘴桃主产区58个样品,运用电感耦合等离子体发散光谱法（inductively coupled plasma spectrometer, ICP）检测14种矿物元素,液相色谱法测定4种可溶性糖组分和4种有机酸组分。运用灰色关联度分析矿物元素、糖酸组分、总糖和总酸含量等营养成分含量与糖酸比的关联度。结果 鹰嘴桃样品的14种矿物元素(K、P、Mg、Ca、Na、Al、Fe、Cu、Mn、B、Zn、Co、Ni、Li), 含量分别为1682～2781、101.7～225.6、51.05～95.90、32.05～105.30、31.24～57.01、0.15～5.85、0.71～9.28、0.15～1.39、0.34～3.53、0.81～2.14、2.01～6.00、0.010～0.066、0.011～0.130、0.022～0.056 mg/(kg FW);4种糖组分(蔗糖、山梨糖醇、葡萄糖、果糖)的含量分别为165.12～367.58、28.90～85.93、20.68～34.39、11.24～29.21 mg/(g FW);4种有机酸组分（苹果酸、奎尼酸、柠檬酸、琥珀酸）的含量分别为1.61～4.19、1.08～3.00、0.14～0.76、0.022～0.100 mg/(g FW)。矿物元素、可溶性糖组分和有机酸组分跟鹰嘴桃糖酸比都有较高的关联度。P、K、Na、Mg含量与糖酸比关联度相对较高;蔗糖含量与糖酸比关联度最大,果糖含量关联度相对最小;有机酸组分与糖酸比关联度依次为苹果酸＞奎尼酸＞琥珀酸＞柠檬酸。结论 糖酸比可以较好的反映鹰嘴桃的品质。P、K、Na、Mg、蔗糖含量、苹果酸含量与鹰嘴桃品质关联度相对较大。     

蜂蜜搀假的物理鉴别法初探

通过常见物理特性及流变性差异鉴别蜂蜜是否搀假.在室温下按常见方法向蜂蜜中搀入蔗糖、CMC-Na、果胶、淀粉、氯化钙、尿素和水,然后测定其pH、电导率、糖度、粘度、密度及流变性.实验结果表明,纯蜂蜜与搀假蜂蜜都属于非牛顿流体;搀蔗糖蜂蜜用流变性难以鉴别,只能通过加水后粘度变化鉴别;其余搀假蜂蜜可通过其流变性和某些物理性能不同而与纯蜂蜜区分开.     

Influence of the cultivar on the organic acid and sugar composition of potatoes

BACKGROUND: Citric, malic, tartaric, oxalic, ascorbic, aconitic and fumaric acids, and sucrose, fructose and glucose, were determined in ten potato cultivars (Azucena negra, Bonita, Bonita negra, Borralla, Colorada de baga, Mora, Negra, Palmera lagarteada, Peluca blanca and Terrenta) from the Canary Islands in order to differentiate them. The influence of the production zone was also considered. RESULTS: Citric acid and sucrose were the most abundant organic acid and sugar, respectively. There were significant differences in all the analysed sugars and organic acids between the potato cultivars, except for oxalic and malic acids. Differences associated with the production zone were found in the contents of organic acids for some cultivars. Linear discriminant analysis is a useful tool to differentiate the potato samples according to the cultivar and the zone of production. CONCLUSIONS: Seven organic acids (citric, oxalic, malic, tartaric, aconitic, fumaric, and ascorbic acids) were identified and quantified in potatoes. The main sugars (sucrose, glucose and fructose) were also determined. The genetic information of the cultivars determines marked differences in sugars and organic acid contents among the analysed potato cultivars. The soil and climatic conditions affect the organic acid and sugar contents of some potato cultivars. Copyright © 2010 Society of Chemical Industry     

Experimental determination of the compression resistance of differently shaped wood particles as influencing parameter on wood-reduced particleboard manufacturing

The price for industrial wood and, thus, particles for the manufacture of particleboard has been rising in the past and will be a topic of current interest in the future as economic growth is targeted at limited resources. One of the strategies to overcome this development is to reduce the amount of wood used for panel production. However, a simple reduction in the amount of wood used for panel manufacture leads to panels of lower density and, consequently, reduced properties. One approach to solving this problem is to re-engineer the particle mat structure to improve the panels’ density profile and, thus, meet required panel properties and at the same time lower board densities. As the particles’ compressibility is one of the main influencing parameters for density profile formation, it is the intention of this study to use a previously developed measurement method to give compression resistances of particles of various shapes and dimensions. It was found that the bulk density alone is not decisive for the particles’ compression resistance. The compression resistance derived from the change of particle shape is lower than that derived from wood substance compression. The compression resistance of large-sized particles was found to be higher than that of small-sized particles. It was concluded that a targeted combination of face and core layer particles improves the panels’ density profile.     

Effect of Agglomeration on Flowability of Baby Food Powders

Abstract: The aim of this study was to investigate the influence of the wet agglomeration in a fluidized bed on flowability of agglomerated products, such as baby food powders. The agglomeration process was performed in the fluidized bed. The wetting liquid used to the process was: water, 2% lecithin solution, and 50% sugar solution. Food powders flowability was expressed as: Hausner Ratio, pouring time, angles of sliding and of repose and flow function. The composition of materials, used to prepare mixtures, has a significant influence on tested properties. The higher milk powder of the mixtures caused decreasing of their flowability. Wet agglomeration of baby food powders caused an increase in the mean diameter of particles, which made it possible to receive agglomerates with good flowability and decreased bulk density. The increase of milk powder content from 0 to 73% in the mixture before the agglomeration contributed to improve its flowability. Wet agglomeration with 2% lecithin solution and 50% sugar solution reduced particle size and bulk density, improved flowability of received agglomerates in relation to agglomerates received with water as a wetting liquid. Practical Application: Agglomeration of baby food powders increases particle size of received agglomerates with a tendency to reduce their bulk density. Agglomerates flowability determined by using practical tests (Hausner ratio, pouring time, angles of sliding and of repose) is not sufficient for a comprehensive assessment of powdered deposit. For complex flow behavior, like that of agglomerated baby food powders, the Jenike shear test only remains as an acceptable test of flowability.     

Evaluation of the Effects of Liquid Bridges on the Bulk Properties of Model Powders

Measured amounts of water were admixed with uniform size glass beads (107-475 micron) to form model powders with controlled interparticle liquid films. The viscosity of the films was modified by dissolving carrageenan and its surface tension by a detergent. These model powders were tested for loose bulk density, compressibility, irrecoverable work in compaction, cohesion and residual modulus after relaxation. The effect of the films on these bulk characteristics was considerable in the fine model powders but diminished with the increase of particle size. In comparison to particle size, the film viscosity (l-2000 cp) and surface tension (72 and 35 dyne cm^?1) had little or insignificant effect on the bulk properties. The results are explained in terms of the internal structure of the bed and their possible implications in real powders are evaluated.     

1-甲基环丙烯对李果实采后衰老期间非挥发性风味物质影响的多变量分析

采用多变量分析的方法研究1-甲基环丙烯(1-MCP)对‘黑琥珀’李果实20℃贮藏期间非挥发性风味物质形成的影响。结果表明：李果实中主要的糖酸组分是D-果糖、D-葡萄糖、蔗糖、山梨糖醇和苹果酸,D-果糖在采收时与贮藏前期释放较多,蔗糖在贮藏后期时含量较高;1-MCP处理抑制了蔗糖向D-果糖和D-葡萄糖的转化,延缓了可溶性固形物含量的下降,在贮藏后期,1-MCP处理诱导苹果酸、柠檬酸和L-天冬氨酸含量的降低,而增加了果实的pH值。偏最小二乘回归与通径分析结果表明,感官甜酸比与山梨糖醇、蔗糖呈高度正相关,酸度与苹果酸呈高度正相关,且蔗糖是甜酸比的主效因子,对甜酸比的影响主要是通过对山梨糖醇、D-果糖和苹果酸的间接效应实现的。