Automated analytical method for the determination of individual sugars in mixtures of glucose,fructose and sucrose

An automated colorimetric method, using p-hydroxybenzoic acid hydrazide and 2-thiobarbituric acid as colour reagents for the determination of total reducing sugars and fructose respectively, is described. The normal measurement range of reducing sugars is 50–1500 mg litre^?1, but with a simple modification of the autoanalyser arrangement it can be reduced to 1–30 mg litre^?1 or increased to 500–6000 mg litre^?1 without affecting the linearity of the calibration curve. Recovery of sugars by the known addition technique using this method range from 97 to 104%. The method is applicable for the joint determination of glucose, fructose and sucrose in fruits, vegetables and fermentation liquors.     

Total,non-volatile free fatty acids as a freshness index for hake (Merluccius hubbsi) stored in ice

Total, non-volatile free fatty acids (FFA) content was determined in hake muscle during fish storage in ice. FFA increased linearly in every season according to freshness loss as determined by sensory scoring. FFA determination is proposed as a valuable alternative to sensory scoring in determining fish deterioration in ice.     

Quantification of glucose,fructose and sucrose in bayberry juice by NIR and PLS

Bayberry plays an important role in the nutrition and is a very important fruit-product. It has a high economic and officinal value. In this study, glucose, fructose and sucrose in bayberry juice were detected and quantified using near-infrared (NIR) spectroscopy. The HPLC method was assumed to provide the reference value of the analyte for calibration. Partial least-squares regression (PLSR) was used to construct calibration models with different pre-processing methods. The number of PLS factors was optimised. The results show PLS models are good for predicting glucose, fructose and sucrose concentrations in bayberry juice, and their prediction accuracy can be improved by using derivative process with the exception of the glucose. The best models were mostly given by the second derivative processed spectra, especially for sucrose with the determination coefficient, R² of 0.9931. This demonstrates the potential of NIR spectroscopy to quickly detect these components simultaneously in bayberry juice with the reference method of HPLC.     

HPLC-ELSD法测定微胶囊中阿拉伯糖、果糖、葡萄糖、蔗糖、麦芽糖、乳糖含量

建立高效液相色谱-蒸发光散射法(High performance liquid chromatography with evaporative light-scattering detection,HPLC-ELSD)同时测定微胶囊中阿拉伯糖、果糖、葡萄糖、蔗糖、麦芽糖、乳糖含量的高效液相色谱方法。样品经乙腈水超声波浸取,采用Waters Amide色谱柱(4.6×250mm3.5μm)分离,以1%氨水和乙腈为流动相,使用蒸发光散射检测器进行检测。结果表明,阿拉伯糖:0.44~7.06mg/mL、果糖:0.30~4.74mg/mL、葡萄糖:0.40~6.45mg/mL、蔗糖:0.32~5.04mg/mL、麦芽糖:0.40~6.47mg/mL及乳糖:0.41~6.61mg/mL范围内线性关系良好;方法检出限为0.02~0.03mg/mL;回收率为95.31%~105.33%,6种糖含量相对标准偏差在2.30%~3.50%之间。该方法前处理简单、灵敏度高和检测速度快,适用于微胶囊中阿拉伯糖、果糖、葡萄糖、蔗糖、麦芽糖、乳糖的定量检测。     

高效液相色谱法检测乳制品中果糖、葡萄糖、蔗糖和乳糖的含量

建立用高效液相色谱法同时测定乳制品中果糖、葡萄糖、蔗糖和乳糖含量的方法。以乙腈-水(体积比75:25)为流动相,通过氨基柱分离和示差折光检测器测定四种糖的含量。在2～20mg/mL范围内线性良好,果糖、葡萄糖、蔗糖和乳糖精密度分别为2.90%、1.41%、1.40%和2.79%,相应的回收率分别为94.96%、104.61%、104.56%和97.87%,此法具有快速准确的特点。     

Dynamic mechanical thermal analysis of aqueous sugar solutions containing fructose, glucose, sucrose, maltose and lactose

The glass transition of glucose, fructose, lactose, maltose and sucrose solutions at maximum cryo-concentration was studied by Dynamic Mechanical Thermal Analysis (DMTA), using the disc bending technique. The glass transition temperatures were determined from the peaks in the loss modulus E ', which corresponds theoretically to the resonance point (Maxwell model) for several input frequencies. The frequency dependence was well described by both an Arrhenius-type model and by the WLF (Williams, Landel and Ferry) equation, yielding glass transition temperatures for an average molecular vibration time of 100 s, which were similar to published midpoint temperatures determined by DSC scans. Some sugar mixtures were studied, yielding results that were well described by the Gordon–Taylor equation, using literature data. The frequency dependence of the viscoelastic ratio was also well approximated by an Arrhenius-type equation, with activation energies similar to those of the glass transition temperature and corresponded well to published values of the endset of glass transition.     

HPLC-CAD法测定乳制品中果糖、葡萄糖、蔗糖、乳糖、半乳糖和麦芽糖含量的不确定度评定

目的采用高效液相色谱(HPLC)串联电喷雾检测器(CAD)法同时测定乳制品中果糖、葡萄糖、蔗糖、乳糖、半乳糖和麦芽糖的含量,分析果糖、葡萄糖、蔗糖、乳糖、半乳糖和麦芽糖不确定度。方法通过HPLC-CAD法测定乳制品中果糖、葡萄糖、蔗糖、乳糖、半乳糖和麦芽糖的含量方法建立数学模型,对各个不确定度因素进行评估、计算,由此计算合成不确定度,最终给出测量结果在95%置信区间下的扩展不确定度。结果本次实验含量测定结果为果糖2.15±0.009(g/100g)葡萄糖7.7490±0.010(g/100g)蔗糖24.5571±0.014(g/100g)乳糖19.8333±0.021(g/100g)半乳糖1.0168±0.026(g/100g)麦芽糖1.8727±0.019(g/100g)。结论所建方法可行,适用于乳制品中果糖、葡萄糖、蔗糖、乳糖、半乳糖和麦芽糖含量的测定。     

Cost‐effective colorimetric microtitre plate enzymatic assays for sucrose,glucose and fructose in sugarcane tissue extracts

Quantification of sucrose, glucose and fructose is essential for developing a physiological understanding of growth and development of plant species. This is usually achieved by either HPLC or enzymatic assays for specific sugars. The need for reliable and cost‐effective assays of large numbers of samples led us to compare microtitre plate‐adapted enzymatic assays for sucrose, glucose and fructose with current HPLC protocols. The enzymatic assay techniques were modified without loss of precision or accuracy when compared to the original protocols. Application of HPLC and the modified enzymatic assay to a range of sugarcane stem extracts found no difference in assay sensitivity. The enzymatic assay had considerable advantages in terms of sample throughput and cost‐effectiveness. © 1999 Society of Chemical Industry     

Separation of fructose,glucose and sucrose in fruit by high performance liquid chromatography using UV detection at 190 nm

Fructose, glucose and sucrose were separated by high performance liquid chromatography (h.p.l.c.) on a 5 μm amine column and detected by absorbance at 190 nm. The procedure quantified these sugars in orange juice and in carambola fruit, but preliminary ion exchange column chromatography was necessary before satisfactory h.p.l.c. results could be obtained. The method is sensitive to 1.2 μg of fructose or 9 μg of glucose or sucrose.     

Effect of cold storage and ozone treatment on physicochemical parameters,soluble sugars and organic acids in Actinidia deliciosa

The production of kiwi fruits is a dynamic agricultural activity in Corsica (France). The fruits are either consumed directly or used to produce kiwi wine. They are often stored for 4–6 months in industrial freezer chambers at 0 °C or industrial ozone chambers. The aim of this study was to measure physical, chemical and fungicidal parameters, soluble sugars and non-volatile organic acids during storage in each of these types of chamber. Various standard and instrumental methods (physicochemical techniques, HPLC) in conjunction with statistical analysis were used. During storage, the kiwi mass, firmness and acidity decreased, whereas reducing sugar, °Brix and pH increased. There were statistical differences between the two chambers regarding reducing sugar and acidity. The ozone gas treatment had a fungicidal effect on Botrytis cinerea. The major soluble sugar present in the kiwi fruit was fructose, followed by glucose and sucrose. The concentrations of these sugars increased during storage in both air at 0 °C and ozone-enriched air. Organic acids are one of the important factors influencing fruit flavour. Citric and quinic acids predominated over malic, tartaric and ascorbic acids. During storage in the ozone chamber, concentrations of non-volatile organic acids decreased sharply after 25 weeks. Storage at 0 °C enabled better retention of organic acids.     

Novel application of an optical inspection system to determine the freshness of Scomber japonicus (mackerel) stored at a low temperature

Food Science and Biotechnology - This study evaluated the use of an optical inspection system (OIS) to determine the freshness of mackerel (Scomber japonicus). The correlations between the light...     

Impact of xanthan gum,sucrose and fructose on the viscoelastic properties of agarose hydrogels

Mixed carbohydrate systems are of special interest for the food and non-food industry as they offer a versatile range of unique and novel functional properties. However, intense research is required to understand the complex processes occurring in such systems on a molecular level and to be able to modify them aim-oriented. In food, characteristic properties are based on the physicochemical functions of the biopolymers added. Thus, small deformation tests and moisture analysis have been applied to study the impact of xanthan gum and two types of sugar on the viscoelastic properties, the sol–gel transition and the water holding capacity of 1% agarose hydrogels. Agarose gels are very elastic, turbid and prone to synaeresis, which impinges on their mouth feeling. Additions of xanthan gum revealed less elastic gels with an unaffected water holding capacity. Progressive addition of two different types of up to 40% of sugar yield an increase of the elasticity of agarose gels, whereby sugar concentrations of 60% partially result in a structural breakdown and thus a significant lower network structure but better water holding. In ternary systems, the effect of the sugar concentration and sugar type used is diminished by xanthan gum. The gelation mechanism of agarose gels with a distinct amount of co-solutes is presumably mainly affected by the water shortage evolved from the competition for it of all solutes present.     

Microbial counts and invert sugars in juice extracts from stored tubers of Cyperus esculentus Linn. (earth almond)

The microbial populations and the levels of invert sugars in juice extracts from healthy tubers of Cyperus esculentus L. stored at 10, 20, 30 and 40 °C were determined. Bacterial counts increased with time and attained the peak on the 25th and 35th d at 40 and 30 °C respectively. Similar trends were obtained for the yeasts, but the peak counts were recorded on the 20th and 35th d at 40 and 30 °C respectively. At 10 and 20 °C, the counts, both for bacteria and yeasts increased throughout the 40-d period. Invert sugar levels increased throughout the investigation period at all the tested temperatures. Highest levels were recorded at about 30 and 40 °C while the lowest levels were obtained at 10 °C. Of the seven bacteria and five yeasts tested, only Saccharomyces rouxii, S. cerevisiae, Schizo-saccharomyces sp., Pseudomonas chlororaphis, P. fluorescens and Bacillus subtilis brought about significant hydrolysis of sucrose in vitro. Results on the microbial populations and levels of invert sugars in raw juice extracts suggest that yeasts could possibly play a greater role than bacteria in the hydrolysis of sucrose in vivo.     

Ion-exchange chromatographic analysis of soluble cations,anions and sugars in milk whey

Three ion-exchange chromatography methods for the separation and quantification of soluble compounds, including cations, anions and carbohydrates in liquid whey were developed. While cations and anions were successfully separated by ion chromatography coupled with electrochemical suppressed conductivity detection, carbohydrate analysis was accomplished by high-pH anion exchange chromatography in conjunction with pulsed amperometric detection. All separations were performed under isocratic elution conditions. With a simple sample preparation, these methods enabled interference-free identification and sensitive quantification of whey soluble ions and compounds: Na⁺, NH₄⁺, K⁺, Mg²⁺ and Ca²⁺, Cl^-, SO₄^2-, PO₄^3-, citrate, isocitrate, and lactose along with some minor sugars, such as galactose, glucose, and N-acetylgalactosamine. Whereas no significant differences were observed between the mean concentrations of Na⁺, K⁺ and Mg²⁺ in wheys deriving from bovine milk of different cheesemaking technologies, the free Ca²⁺ content in hard cheeses was less than a half of that found in whey from soft cheeses (560ᆞ mg/l, n=4) as a result of a more favoured solubilization of calcium from the colloidal phase. In spite of an elevated amount of lactose, separation and quantification of minor whey sugars was possible.     

A new procedure for extraction and measurement of soluble sugars in ligneous plants

An original modification of an analytical procedure has been developed to obtain purified extracts for sugar measurement in different parts of ligneous plants by high‐performance liquid chromatography. Extraction was performed at 4 °C in the presence of water, methanol and chloroform. Only a representative part of the alcohol extract (methanol/water) was purified for analysis. An internal marker such as maltotriose, added during extraction, makes it possible to estimate possible sugar loss and to correct concentrations. Compared with a more standard method based on total soluble sugar extraction, this new method is more precise. The use of internal calibration standards shows good linear progression but does not guarantee good accuracy in the absence of a reference method or plant powder standard. It is a robust procedure which can tolerate experimental variations without affecting the results. The high recovery rate (90%) of maltotriose proves the quality of the procedure and makes it possible to correct sugar concentrations to acceptable limits. © 2002 Society of Chemical Industry     

An enzyme‐based method for the rapid determination of sucrose,glucose and fructose in sugar beet roots and the effects of impact damage and postharvest storage in clamps

A high‐throughput enzyme‐coupled assay is described for the determination of sucrose, glucose and fructose in sugar beet roots. This method is sensitive, rapid and inexpensive and has been used to highlight the increases in sucrose loss following root stresses such as freezing or aggressive harvesting. Sugar beet roots lose 12.5% of their sucrose following an episode of impact damage greater than 2 J, rising to 19.7% loss after 8 J, with concurrent increases in glucose and fructose. Increases in glucose and fructose are particularly pronounced following a period of clamp storage (up to 2.3 and 3.3 µg mg^?1 fresh weight, respectively). © 2001 Society of Chemical Industry     

离子色谱法测定奶糖中的蔗糖、葡萄糖和乳糖

建立离子色谱法分离检测奶糖中蔗糖、葡萄糖和乳糖的分析方法。采用METROSEPCARB1（150mm×4.0mm）阴离子交换分离柱和脉冲安培检测器,对淋洗分离条件进行优化。确定柱温为32℃、淋洗液为37.0mmol/L NaOH溶液,淋洗液流速为1.0mL/min,总分析时间20min。在1.0～60.0mg/L范围内蔗糖、葡萄糖和乳糖分别呈良好线性,相关系数分别为0.9996、0.9998和0.9996,检出限分别为0.091、0.014和0.083mg/L,RSD为1.42%～5.17%,回收率为91.27%～101.31%。测定结果为大白兔奶糖中含葡萄糖1.56%、蔗糖21.40%、果糖3.75%;旺仔牛奶糖中含葡萄糖1.17%、蔗糖30.29%、果糖3.30%;金丝猴奶糖中含葡萄糖1.08%、蔗糖20.86%、果糖3.31%。用该方法检测了奶糖中的三种糖,效果良好,同时具有操作简单,结果准确,快速有效等优点,可为奶糖的检测提供一个简单有效的方法。     

离子色谱法测定苦瓜茶中的半乳糖、葡萄糖、甘露糖和果糖

建立了离子色谱法同时分离测定苦瓜茶中的半乳糖、葡萄糖、甘露糖和果糖的分析方法。用METROSEP CARB1(150mm×4.0mm)阴离子交换分离柱和脉冲安培检测器,对淋洗分离条件进行优化。选择了8mmol/L NaOH为淋洗液,淋洗液流速为1.0mL/min,总分析时间为25min。半乳糖、葡萄糖、甘露糖和果糖的检出限分别为0.105、0.126、0.152、0.587mg/L(进样体积20μL)。混标溶液连续8次进样,峰高的相对标准偏差为2.12%~5.43%,保留时间的相对标准偏差为2.06%~3.28%。样品测定的回收率为94.2%~99.8%。该方法具有样品前处理简单,灵敏度高,快速有效等优点。结果满意。为苦瓜茶中糖分的检测提供了一个简单有效的方法。     

高效液相色谱-激光蒸发光散射检测法测定低蔗糖食品中葡萄糖、蔗糖、麦芽糖和乳糖含量

建立了同时测定低蔗糖食品中葡萄糖、蔗糖、麦芽糖和乳糖的高效液相色谱方法。样品经水超声波浸取,采用HypersilNH2柱分离,以乙腈/水(80/20体积比)为流动相,使用激光蒸发光散射检测器进行检测。结果表明,葡萄糖、蔗糖、麦芽糖和乳糖的线性范围分别为15～1000、20～1500、15～1000、12～1000mg/L;检出限为4.5～6mg/L,样品的加标平均回收率为92.9%～99.0%,相对标准偏差在1.9%～3.5%之间。该法用于实际样品的测定,结果另人满意。     

Evaluation of a new insecticide formulation (F2) as a protectant of stored wheat, maize, and rice

A new commercial formulation, F2, was evaluated as a protectant of stored wheat, stored maize, and stored rough (paddy) rice. This formulation comprises the technical active ingredients 0.03% deltamethrin, 0.37% piperonyl butoxide, and 0.95% chlorpyriphos-methyl, plus 10% mineral oil and 88.0% of the diatomaceous earth Protect-It^®. Tests were conducted with dust and slurry formulations at 50 and 100 ppm, 57% and 75% relative humidity, and 22°C, 27°C, and 32°C. On wheat, survival of the lesser grain borer, Rhyzopertha dominica (F.), ranged from 0% to 30.0%, survival of the rice weevil, Sitophilus oryzae (L.), was 0-6.2%, and survival of the red flour beetle, Tribolium castaneum (Herbst), was 0-97.5%. Few F₁ adults of any of the three species were found in the treated samples. Survival of the maize weevil, Sitophilus zeamais (Motschulsky), on treated corn was 0-32.5%, while survival of T. castaneum was 0-88.7% in the 50-ppm dust and slurry treatments, and 0-51.4% in the 100-ppm treatments. Again, few F₁ adults of either species were found in treated maize. Survival of R. dominica on treated rough rice averaged 0-4.1% and survival of S. oryzae on treated rice was 0-48.8%, but the majority of weevils that survived were in one replicate. F₁ adults in the treatments ranged from 0 to 24.4. Results show that the combination insecticidal product F2 was extremely effective on all three commodities at the rate of 100 ppm, as either a dust or slurry, and could be used as a commodity protectant.