An enzymatic method for the determination of fructans in foods and food products

 We report a new and non-equipment demanding method of measuring the content of fructans as well as the contents of free glucose, free fructose and sucrose in foods and food products enzymatically. This method comprises hydrolysis of fructans into d-glucose and d-fructose enzymatically and measurement of the released sugars enzymatically. Sucrose is hydrolysed by α-glucosidase instead of β-fructosidase, which is normally used. In addition, sucrose is measured in the form of d-fructose instead of the typical d-glucose form, and the fructanase used to hydrolyse the fructans has fewer side effects than the fructanase reported as normally used. The method is tested on ten standard substances and five fructan products, and nine foods and food products are also analysed. The enzymatic measurement of the released sugars is confirmed by measurements done by high performance anion exchange chromatography with pulsed amperemetric detection. Received: 1 March 1999 / Revised version: 23 April 1999     

紫苏泡腾片固体饮料的研究

目的研究紫苏泡腾片的制备工艺,确定原辅料配比。方法采用酸碱混合非水制粒法,经原辅料混合、制软材、干燥、整粒、压片等工序,制备紫苏泡腾片。结果紫苏泡腾片最佳配方为：紫苏提取物干粉10％,柠檬酸49％,碳酸氢钠35％,阿拉伯胶4％,聚乙烯吡咯烷酮（PVP）0．5％,三氯蔗糖0．7％,聚乙二醇8000 0．8％。咀嚼片表面光滑、酸甜可口、营养丰富,且能防龋齿、改善肠胃功能。其中,柠檬酸、碳酸氢钠和阿拉伯胶是紫苏泡腾片崩解时限的主要影响因素,以柠檬酸对其影响最大。结论该工艺简单,操作方便,节约能源;所制固体饮料酸甜可口,片剂表面光滑整洁、呈紫苏的亮紫红色。     

黄蜀葵泡腾片制备工艺的研究

制备口感良好,具有保健功能的黄蜀葵泡腾片。通过单因素试验与响应面分析法结合来优化黄蜀葵泡腾片中碳酸氢钠与柠檬酸的质量比,药粉的添加量和甜菊糖苷的添加量。采用酸碱分别制粒后,以混合压片的方法制备黄蜀葵泡腾片。黄蜀葵泡腾片优化得到的最佳配方的主要成分为:碳酸氢钠16%,柠檬酸32%,黄蜀葵7.5%,甜菊糖苷4.5%。试验所制得的泡腾片具有黄蜀葵清新甘甜的口味,便于携带和食用,易被消费者接受。     

Chemical characterization and antioxidant activity of an exopolysaccharide fraction isolated from <Emphasis Type="Italic">Bifidobacterium animalis</Emphasis> RH

The major exopolysaccharide fraction (EPSa) of Bifidobacterium animalis RH was purified to illustrate the chemical characterization and the antioxidant activity in vitro. The molecular weight of EPSa was 2.31 × 10⁴ Da determined by the gel permeation chromatography (GPC). Fourier-transform infrared spectra (FT-IR) and the monosaccharide analysis of high-pH anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) showed that it was a heteropolysaccharide mainly composed of d-glucose, d-mannose, d-galactose, l-arabinose, d-fructose, and l-rhamnose in molar ratios of 43:34:18:4:1:1. In antioxidant assays, the EPSa had a higher activity for antilipid peroxidation and a stronger scavenging activity of hydroxyl radical and superoxide radical than ascorbic acid. It also had a similar α,α-diphenyl-β-picrylhydrazyl (DPPH) radical-scavenging activity with ascorbic acid at low concentration and had concentration-dependent inhibitory ability on erythrocyte hemolysis. These results indicated that the EPSa fraction had strong antioxidant activities and could be explored as novel potential antioxidants.     

苦瓜泡腾片固体饮料的研制

以苦瓜粉、柠檬酸、NaHCO3、阿斯巴甜、麦芽糊精、白砂糖等为原料,探讨苦瓜泡腾片固体饮料的加工工艺,对饮料配方的确定,粘结剂和润滑剂的选择,苦瓜粉制作工艺条件的确定等进行研究,同时分析苦瓜粉、甜味剂、泡腾剂等加入量对饮料品质的影响。通过正交试验最终确定泡腾片最佳配方为:苦瓜粉4.0%;白砂糖17.8%,阿斯巴甜3.6%;碳酸氢钠31.1%,柠檬酸35.6%,麦芽糊精6.7%。同时添加少量PVP(聚乙烯吡咯烷酮)无水乙醇溶液、PEG6000(聚乙二醇6000)和维生素C分别作为粘合剂、润滑剂和抗氧化剂。制成的苦瓜泡腾片饮料感官优良、口味独特,除去了苦口性,容易被消费者接受。     

Starch radicals Part III: Semiartificial complexes

 Nine starch varieties were blended and kneaded with d-fructose, d-glucose, sucrose, egg albumin and/or ethyl stearate to form semiartificial complexes. They were then thermolyzed and the numbers of unpaired spins in the solid residues were determined. Individual starch varieties began to generate unpaired spin states within 2 h of heating at 285  °C but some starch blends, particularly those of four-component starch (10 : 1 : 1 : 1) mixtures, generated free radicals within 2 h of heating at 160  °C. However, the free radical counts were minimized by the mutual complexation of the blend components and, to a certain extent, by the free radical scavenging in the blends. Received: 21 October 1997 / Revised version: 15 April 1998     

Enzymatische Bestimmung von S?uren in Wein I. Mitteilung ?pfels?ure, Milchs?ure, Citronens?ure

Zusammenfassung Nach Ausschaltung von Störungsmöglichkeiten durch Farbstoffe und Gerbstoffe kann die enzymatische Bestimmung vonl-Malat,l-Lactat und Citrat in Wein einwandfrei durchgeführt werden. Äpfelsäure kommt in Wein nur in derl-Form vor, Lactat dagegen sowohl in derd- als auch in derl-Form. Die beiden Antipoden stehen in keinem bestimmten Verhältnis zueinander, jedoch überwiegt bei hohen Milchsäuregehalten der Anteil derl-Form.

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Enzymatic determination of acids in wine I. Malic-, lactic- and citric-acid

Summary The enzymatic determination ofl-malate with MDH,l-lactate with LDH and citrate with citrate — lyase was carried out in more than 100 samples of white and red wine, after elimination of interfering substances, such as tans and colouring matters. The contents ofl-malate and citrate agreed very well with the results, found by a fractionation method on silica gel. Comparing the content of total lactate, found by the latter method, with the results of enzymatic determination ofl-lactate, it was obvious, thatd- andl-compounds occur in a different ratio, but at high lactic acid concentrations, however, the level of thel-form is higher.

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Auszug aus der Dissertation vonSiegfried Looser: Beitrag zur enzymatischen Analyse von organischen Säuren und Kohlenhydraten in Lebensmitteln. Technische Hochschule München 1968.     

蔗糖水解制取结晶果糖技术研究

为提升制糖产业的综合效益,以白砂糖为原料开发附加值更高的结晶果糖,探讨用蔗糖原料制取高纯度结晶果糖的最优工艺方法。实验以高浓度蔗糖液(55%w/w)为原料,食品酸味剂柠檬酸为水解剂,通过蔗糖水解、脱色、阴阳离子树脂除盐,以钙型树脂分离、纯化果葡糖液,在常温下得到结晶果糖和结晶葡萄糖。实验优化蔗糖最佳水解工艺条件:水解温度80℃,水解时间4.0 h,柠檬酸用量0.50%,蔗糖水解率为100%;果糖结晶工艺条件:在水-乙醇比例为1∶4的体系下,果糖纯度88%以上、糖膏固形物含量87°Bx以上、晶种用量为糖膏总量5%、养晶时间48 h,果糖结晶率达到56.34%;葡萄糖结晶工艺条件:在水-乙醇比例为1∶2的体系下,葡萄糖纯度65%以上、糖膏固形物含量83°Bx以上、晶种用量为糖膏总量5%、养晶时间48 h,葡萄糖结晶率达到63.27%。实验选择高浓度蔗糖液水解及常温下结晶的方式,可降低能源消耗,同时通过将纯度65%以上的葡萄糖液直接结晶分离,使母液中果糖纯度从33.3%提升至60.2%,起到了分离纯化果糖液的效果,有效减轻果葡糖液的分离负荷。     

Characterization and Utilization of Acid‐modified Rice Starches for Use in Pharmaceutical Tablet Compression

Acid modified, agglomerated starches offer specific advantages as fillers in production of pharmaceutical tablets. Spray drying can improve processing of tablet mixtures significantly. In order to investigate prerequisites in utilization of rice starch, non‐waxy and waxy types were partially hydrolyzed in 6% (w/v) HCl solution at room temperature for varied length of time to obtain rice starches with increased crystallinity (so‐called crystalline rice starches). Scanning electron micrographs of native and highly crystalline starches were used to study the morphological changes and to suggest the mode of acid attack during hydrolysis. Exo‐corrosion distributed over the surface of acid‐modified waxy rice starch (AWRS) was observed after 192 h of hydrolysis. In contrast, the surface of acid‐modified rice starch (ARS) remained unchanged at 192 h of acid hydrolysis. The amylose content and the median particle size (diameter) were reduced with increasing hydrolysis time. It was found by X‐ray diffraction that the relative crystallinity of acid‐modified starches at >95% relative humidity was clearly increased with prolonged hydrolysis time. For studying tablet properties spherical agglomerates of the native and acid modified starches were directly compressed at 4 kN to obtain tablets. Crushing strength and disintegration time of tablets increased with relative crystallinity. In contrast, tablet friability was reduced. Concerning tablet functionality, the crystalline starches were positioned in overlapping ranges between the common commercial tablet fillers (microcrystalline cellulose, pregelatinized starch and lactose, respectively).     

Hydrolysis of soya milk oligosaccharides by Bifidobacterium longum CRL 849

 The reduction of soya milk oligosaccharides by Bifidobacterium longum CRL 849 was studied. The utilization of stachyose was concomitant with the use of sucrose. Maximum hydrolysis of stachyose (49.3%) occurred during the first 7 h of incubation at 37  °C, while a 79.3% decrease in the concentration of sucrose was observed after 9 h. No raffinose was detected after hydrolysis of the stachyose. Cell population decreased after 8 h of incubation because of the low pH attained (pH 4.7). l(+)-Lactate concentration was higher than acetate (molar ratio 6.7 : 1) at 6 h followed by a slow increase in acetate formation. Ethanol was detected in small amounts at the end of the incubation time (24 h). Received: 29 December 1997     

Gas chromatographic detection of d-amino acids in natural and thermally treated bee honeys and studies on the mechanism of their formation as result of the Maillard reaction

Relative quantities of d-amino acids, (%D) calculated from the sum of d- and l-amino acids were determined in bee honeys (n=6) by GC-SIM-MS. Amino acids were isolated by treatment with Dowex 50 W X8 cation exchanger and converted into N(O)-perfluoroacyl amino acid propyl esters. In all honeys d-Ala, ranging from 2.2–6.2% d-Ala, was detected. Other d-amino acids were also found, albeit not in all honeys and approached 5.9% d-Glx, 5.4% d-Lys, 3.0% d-Phe, 2.1% d-Orn, 1.7% d-Asx, 1.5% d-Ser, 0.1% d-Pro, and 0.4% d-Val in certain honeys. Quantities of d-amino acids increased very much on experimental heating of honeys in an oven and on a microwave treatment. Conventional heating of a forest honey (no. 1) at 65 °C for 450 h leads to an increase of d-Ala (2.2–12.5%), d-Pro (0.0–5.0%), d-Ser (1.5–9.1%), d-Asx (1.7–9.8%), d-Phe (0.4–5.0%) and d-Glx (1.5–5.8%); first numbers in parentheses refer to unheated honeys. Relative quantities of other d-amino acids also increased. Experimental heating of another forest honey (no. 2) in a microwave oven for 3 min at 180 W leads to an increase of d-Ala (3.7–11.0%), d-Glx (1.5–13.7%), d-Asx (0.7–10.2%), d-Phe (0.3–4.8%), d-Val (0–4.2%), and d-Pro (0.1–2.3%). Microwave treatment at 700 W for 1 min of a blossom honey (no. 3) leads to an increase of d-Ala (6.2–26.7%) and of d-Phe (3.0–10.9%). Microwave treatments were accompanied by intensive destruction of amino acids. Heating of a model mixture mimicking the major components of honey (d-glucose, d-fructose, and l-amino acids at 20% water content) at pH 2.6–9.0 and at 180 W for 1–3 min leads to the generation of d-amino acids and was also accompanied by intensive decay of amino acids. From the data it is concluded that d-amino acids are formed in honeys in the course of the Maillard reaction. A mechanism is presented based on amino acid racemization of reversibly formed Heyns and Amadori compounds (fructose-amino acids).Parts of the results have been presented at 9th International Congress on Amino Acids and Proteins, August 8–12, 2005, Vienna, Austria, and Euro Food Chem XIII, September 21–23, 2005, Hamburg, Germany.     

AB益生菌纤维咀嚼片加工工艺的研究

以玉米皮为主要原料,采用酸碱与酶复合法制成玉米膳食纤维基料。建立双歧杆菌、嗜酸乳杆菌混合发酵工艺。通过正交实验确定了AB益生菌咀嚼片的最佳处方及最佳工艺条件,经混合、造粒、干燥、压片等工序加工后,制成具有保健功能的AB益生菌纤维咀嚼片。     

雄蜂蜂体营养片的研制

本实验以雄蜂蜂体为主要原料,研制出食用方便且风味、口感、性能俱佳的雄蜂蜂体营养片产品,采用L9(43)正交试验进行配方优选,并比较了不同润滑剂、不同压片方法对压片效果的影响。实验结果表明,影响雄蜂蜂体营养片口感的原辅料主次顺序依次为柠檬酸>雄蜂蜂体粉>阿斯巴甜>蔗糖,优化的最佳雄蜂蜂体营养片配方为:雄蜂蜂体粉20g/100g、蔗糖20g/100g、阿斯巴甜300mg/100g和柠檬酸300mg/100g。采用制粒压片法,以硬脂酸镁、微粉硅胶为润滑剂,压片效果好,压片过程中不黏冲,成品表面点状颗粒分布均匀、整洁有光泽,片结实、不易碎。     

Chiral amino acid analysis of vinegars using gas chromatography – selected ion monitoring mass spectrometry

 Twenty-five vinegars were examined quantitatively for their content of free amino acid (AA) enantiomers using chiral gas chromatography/mass spectrometry. Vinegars manufactured from grape must contained l-proline (l-Pro) as the major AA. Balsamic vinegars (aceto balsamico di Modena), with one exception, contained the highest amounts of l-AAs (861–2000 mg l^–1) as well as d-AAs (46–361 mg l^–1). The amounts of d-Pro and d-alanine (d-Ala) increased in the course of maturation. Sherry vinegars had a AA pattern similar to that of balsamic vinegars but with much lower amounts: concentrations of l-AAs were 244 mg l^–1 and 456 mg l^–1 and of d-AAs were 18 mg l^–1 and 19 mg l^–1. The l-AA content of cider vinegars was very low (34 mg l^–1 and 44 mg l^–1) and only traces of d-AAs (<2 mg l^–1) were found. In spirit vinegars few d-AAs and low amounts of most l-AAs were detected, with the exception of l-glutamic acid (l-Glu) (210–847 mg l^–1), probably added as a flavour enhancer. The AA content of spirit vinegars blended with wine vinegar was influenced by the portion of wine vinegar added. Rice vinegars had concentrations of l-AAs from as low as 36 mg l^–1 to as high as 6860 mg l^–1, and the concentrations of d-AAs ranged from 6 mg l^–1 to 531 mg l^–1. All vinegars declared as "produced by microbial fermentation" contained d-Ala, d-aspartic acid, and d-Glu as typical bacterial markers. From the data it is concluded that chiral AA analysis can be used to distinguish among fermented and synthetic vinegars and to identify raw materials used for their production. In particular, the amount of d-Pro can be used as proof of the maturation process of balsamic vinegar. Received: 11 December 1997 / Revised version: 12 May 1998     

Chiral amino acid analysis of vinegars using gas chromatography – selected ion monitoring mass spectrometry

 Twenty-five vinegars were examined quantitatively for their content of free amino acid (AA) enantiomers using chiral gas chromatography/mass spectrometry. Vinegars manufactured from grape must contained l-proline (l-Pro) as the major AA. Balsamic vinegars (aceto balsamico di Modena), with one exception, contained the highest amounts of l-AAs (861–2000 mg l^–1) as well as d-AAs (46–361 mg l^–1). The amounts of d-Pro and d-alanine (d-Ala) increased in the course of maturation. Sherry vinegars had a AA pattern similar to that of balsamic vinegars but with much lower amounts: concentrations of l-AAs were 244 mg l^–1 and 456 mg l^–1 and of d-AAs were 18 mg l^–1 and 19 mg l^–1. The l-AA content of cider vinegars was very low (34 mg l^–1 and 44 mg l^–1) and only traces of d-AAs (<2 mg l^–1) were found. In spirit vinegars few d-AAs and low amounts of most l-AAs were detected, with the exception of l-glutamic acid (l-Glu) (210–847 mg l^–1), probably added as a flavour enhancer. The AA content of spirit vinegars blended with wine vinegar was influenced by the portion of wine vinegar added. Rice vinegars had concentrations of l-AAs from as low as 36 mg l^–1 to as high as 6860 mg l^–1, and the concentrations of d-AAs ranged from 6 mg l^–1 to 531 mg l^–1. All vinegars declared as "produced by microbial fermentation" contained d-Ala, d-aspartic acid, and d-Glu as typical bacterial markers. From the data it is concluded that chiral AA analysis can be used to distinguish among fermented and synthetic vinegars and to identify raw materials used for their production. In particular, the amount of d-Pro can be used as proof of the maturation process of balsamic vinegar. Received: 11 December 1997 / Revised version: 12 May 1998     

Physicochemical characterization and antioxidant activity of a polysaccharide isolated from oolong tea

Oolong tea polysaccharide (OTPS) is a kind of water-soluble polysaccharide isolated from oolong tea. Its molecular weight, composition, and structure were analyzed by laser light scattering analysis, chemical methods, gas chromatography, and atomic force microscopy (AFM). Antioxidant potential was detected by hydroxyl radical scavenging, inhibition of lipid peroxidation, DPPH radical scavenging, and reducing power assays. Results showed that OTPS was a non-reductive acid heteropolysaccharide bound to protein. The amounts of uronic acid, protein and neutral sugar in OTPS were 40.65, 19.59, and 26.66%, respectively. The neutral sugar was composed of d-rhamnose, l-arabinose, d-galactose, and d-glucose with a molar ratio of 1.37:1.89:1.00:1.30. The molecular weight of OTPS was 1.28 × 10⁶ Da and the second viral coefficient was 2.36 × 10⁻⁴ cm³ mol/g². A globular image of OTPS was imaged by AFM. OTPS showed effective antioxidant activities on hydroxyl radical scavenging assay and inhibition assay of lipid peroxidation.     

Optimised quantification method for yeast-derived 1,3-β-<Emphasis Type="SmallCaps">d</Emphasis>-glucan and α-<Emphasis Type="SmallCaps">d</Emphasis>-mannan

The polysaccharides 1,3--d-glucan and -d-mannan show numerous beneficial effects for the health of humans and animals. For several years, an increasing number of glucan- and mannan-containing products intended for food and feed applications are commercially available. For the determination of glucan and mannan contents, however, widely accepted methods have not yet been established. We have developed a practicable and reliable quantification method characterised by acidic hydrolysis with trifluoroacetic acid and subsequent determination of released d-glucose and d-mannose. The unavoidable loss of the monosaccharides due to the acidic conditions was minimised by optimisation of the hydrolysis parameters. The best conditions found were compared with literature methods in order to demonstrate the suitability. Finally, glucan and mannan contents of various commercial products were determined and compared to the specifications given by the manufacturers.     

不同种类的酸对蔗糖的水解催化研究

利用高效液相色谱-蒸发光散射检测法分析测定了盐酸、柠檬酸和酒石酸对蔗糖水解过程中蔗糖、葡萄糖和果糖转化量的变化,并结合酸催化蔗糖水解反应机理对蔗糖水解过程进行研究。结果表明：在pH 2、反应温度90℃时,蔗糖在1 h内能够完全水解,并且不会产生过多的副反应。     

Gas chromatographic evaluation of amino acid epimerisation in the course of gelatin manufacturing and processing

 Using capillary gas chromatography on chiral stationary phases total hydrolysates of gelatins were investigated for their amounts of D-amino acids (D-AAs). Gelatins of different quality and origin were analysed including gelatin-containing final products like candies and meat products. In gelatins manufactured by stepwise extraction (first to fifth extract) with water of increasing temperature (ca. 55–95°C) amounts of 2.7–4.8% of D-aspartic acid (D-Asp) were determined in extracts obtained at ≤ 85°C. The amounts D-Asp were as high as 28.1% in fifth extracts obtained at 95°C (data corrected for 4.3% of D-Asp determined in native collagen as a result of acid-induced epimerisation of L-Asp during total hydrolysis). Epimerisation of aspartyl or asparaginyl residues of proteins in general on heating in water is assumed to proceed via formation of aspartyl succinimide, tautomerisation and release of D-Asp on total hydrolysis. The other AA residues of gelatin showed only a slight increase of epimerisation with increasing thermal treatment. Furthermore, amounts of 3–4% of cis-4-D-hydroxyproline, formed from native trans-4-L-hydroxyproline in collagen on hydrolysis, were detected in total hydrolysates of all gelatins. Received: 8 August 1997 / Revised version: 24 November 1997