固相萃取-高效液相色谱检测啤酒中赭曲霉毒素A

目的建立一种啤酒中赭曲霉毒素A的分析检测方法.方法使用SPE-C18固相萃取,C18反相柱(250×4.6 mm)分离,乙腈-水-乙酸(99992)为流动相,荧光检测器(激发波长333 nm,发射波长460 nm)检测.结果啤酒不同水平的加标回收率为72.8%～87.0%,RSD均小于8.6%.并用该法测定了市售三种啤酒,均在检出限以下.赭曲霉毒素A标准溶液浓度0～200 ng/ml与峰面积呈良好线性关系,线性相关系数为0.9996.根据三倍噪声法.该法检出限为0.023 ng/ml.结论使用SPE-C18柱极大地简化了样品预处理手续,可建立一种简便、快速、准确、实用的啤酒中赭曲霉毒素A的分析方法.     

赭曲霉毒素A与人类健康关系研究进展

赭曲霉毒素A(OA)主要由纯绿青霉、赭曲霉和碳黑曲霉产生 ,主要污染谷物、动物饲料和动物性食品 (猪肾脏、肝脏 ) ,是具有很强力的肝脏毒性和肾脏毒性 ,并有致畸、致突变和致癌作用的一种真菌毒素 ;在世界某些地区 ,该毒素被怀疑与猪真菌毒素肾病有关 ,并在流行区人血液中检出该毒素。膳食摄入OA与人类健康的关系越来越引起人们的重视 ,本文就OA产生菌、对农作物的污染、毒性和危险性分析等诸多方面进行了综述     

Rapid analysis and residue evaluation of six fungicides in grape wine-making and drying

Rapid multianalysis methods of metalaxyl-M, boscalid, picoxystrobin, fluopicolide and its metabolite 2,6-dichlorobenzamide, pyraclostrobin, and mandipropamid in grapes, wine, and raisins were established. The residue determination of six fungicides in wine-making and fruit-drying processes and evaluation were studied. The six fungicides exhibited good linearity in all three matrices (r > 0.9953). The average recoveries of the six fungicides at three added levels were 78.8 %–106.3 % (RSD 0.6 %–12.5 %). During wine-making processes, metalaxyl-M dissipated slowly (T_1/2 = 248 h), while the other five fungicides dissipated rapidly (T_1/2 = 17−44 h). The transfer rates of the six fungicides in wine and pomace were 0.9 %–14 % and 22 %–72 %, respectively. During the drying process, the dissipation of metalaxyl-M was very limited, and the half-lives of the other five fungicides were 39−84 h. The processing factors (PFs) of the six fungicides during wine-making and drying were 0.01-0.19 and 0.35-0.97, respectively, which indicates that these processes can reduce the residues of these six fungicides in wine and raisins. The established multianalysis method provides a reference for the simultaneous detection of target pesticides in grape and its processed products. The residue determination results provide reasonable data for reducing pesticide residues and the dietary risk factors of grapes and their processed products.     

HPLC法测定谷类食品中的赭曲霉毒素A

目的:建立谷类食品中赭曲霉毒素A的HPLC检测方法。方法:样品经提取、过免疫亲和柱净化后,用高效液相色谱-荧光检测器进行分析。结果:赭曲霉毒素A在1~20 ng/m l范围内线性关系良好,r0.999。回收率在80%~110%之间,定量限为1μg/kg,检测限为0.3μg/kg。结论:该方法快速、简便、准确,可作为谷类食品中赭曲霉毒素A定量测定的有效手段。     

Techniques to evaluate changes in the nutritional profile of food products

Food products are continuously reformulated by manufacturers; however, the monitoring of chemical compositional changes is rare. The objective of this study was perform a comparative evaluation of the nutritional profile of specific Brazilian food groups from 2003 and 2013 using various methods of analysis. Amounts of carbohydrate, lipid, protein, dietary fiber (DF) and energy were evaluated in 259 products distributed in four food groups. Products from each group were evaluated by percentage change, separated by principal component analysis (PCA) and hierarchical cluster analysis (HCA). Separation was more clearly observed through the use of HCA than PCA. In the majority of the clusters, a significant difference was observed in at least one component. For instance, a large number of products (53%) in the milk group showed a reduction in the amount of lipids, and products in the cereals and meat groups showed increased amounts of DF (55%) and lipids (40%), respectively. Therefore, the joint techniques applied allowed nutrient content differences to be assessed both in a general manner (percentage change) as well as through the identification of the nutrients in foods that had changed significantly. The results emphasized the need for the periodic monitoring of the nutritional profile of foods.     

Pigments in your food

Twelve years ago the first Pigments in Food conference was organized to bring together scientists specialized in the research of pigments to share their results and problems with each other. The most important aim of the congress was to offer a possibility for scientists such as pigment chemists, food chemists, food technologists, agriculturists, nutritionists, and also industry people from all over the world to meet and discuss the different aspects of food pigments. The content of the conference primarily, but not exclusively, addresses anthocyanins, carotenoids and chlorophylls. This special issue allows the reader to take a look at the versatility of topics that were presented on the most recent congress in the series, namely, the 6th International Congress on Pigments in Food entitled “Chemical, Biological and Technological Aspects” held in Budapest, Hungary, from 20 to 24 June, 2010.     

Optimization of microwave-assisted extraction procedure for zinc and copper determination in food samples by Box-Behnken design

This article describes the application of response surface methodology (RSM) to the development of a procedure for zinc and copper determination by flame atomic absorption spectrometry (FAAS) in food samples after extraction by a microwave system. A Box-Behnken matrix was used to find optimal conditions for the procedure through a response surface study. Three variables “irradiation power; time; and temperature” were regarded as factors in the optimization study. The working conditions were established as a compromise between optimum values found for each analyte taking into consideration the robustness of the procedure. These values were 97 °C, 90 W and 9.0 min, for temperature, irradiation power and time, respectively. The accuracy of the optimized procedure was evaluated by the analysis of certified reference materials. The method was applied to the determination of copper and zinc in wheat flour and corn flour samples.     

Assessing sialic acid content in food by hydrophilic chromatography-high performance liquid chromatography

We have established a novel hydrophilic chromatography (HILIC)-high performance liquid chromatography (HPLC) method to assess sialic acid content in food products. Single-factor and response surface methodologies (RSM) were used to systematically optimize the hydrolysis conditions of the food samples to extract the maximum amount of sialic acid. Chromatographic conditions were also adjusted. In foods containing sialic acid, we observed a strong linear relationship between sialic acid and peak area, ranging from 5 to 100 μg/mL (R² = 0.9998). The lowest detectable sialic acid concentration (RSN = 3) was 0.2 μg mL⁻¹, and the method detection limit was 0.02mg kg⁻¹. Sample recovery ranged from 95.85% to 99.78%, with an RSD of 1.46% (n = 6). Thus, the described method can be applied to the study of sialic acid content in foods.     

Sodium and potassium in composite food samples from the Canadian Total Diet Study

Sodium (Na) and potassium (K) are essential nutrients. Like people in many Western societies, Canadians consume too much Na and not enough K, both of which contribute to hypertension. We analysed the Na and K content of 154 food composites, broadly representative of the foods most commonly consumed in Canada, from the Canadian Total Diet Study collection of 2007. Foods were prepared as if for home consumption before compositing. No salt was added during food preparation. Samples prepared by aqueous extraction were analysed by atomic emission (Na) or atomic absorption spectrometry (K). Processed foods and soups contained large amounts of Na per reference amount (serving) of the food, with 17 samples containing over 1/3 of the Adequate Intake (AI) for adults, or >500 mg Na/serving. Fluid milk, unprocessed meats and several fruits and vegetables contained large amounts of K per reference amount, with 11 samples containing over 10% of the AI for adults, or >470 mg K/serving. Na:K molar ratios were typically either high or low, with few values near unity. Thus, with few exceptions, foods high in Na were lower in K, and vice versa. Through judicious food selection it may be possible for consumers to decrease Na intake while increasing K, with associated health benefits. Such choices would be consistent with common nutrition advice to decrease consumption of processed foods, while increasing intakes of fresh fruits and vegetables.     

Nutrient profile of black coffee consumed in Serbia: Filling a gap in the food composition database

Accurate food composition data is essential in calculating the nutrient intake of a population based upon its consumption statistics. In the Serbian Food Composition Database (FCDB) there is a lack of reliable analytical data for black coffee, even though this is one of the most abundantly consumed beverages. In addition to evaluating the nutritional significance of black coffee consumption in Serbia, this work provides analytical data for inclusion in the Serbian FCDB, and the interchange through EuroFIR FoodEXplorer. Macronutrient, caffeine, chlorogenic acids (CGA), fatty acids and mineral content were analysed in a composite sample of roasted ground coffee, as well as in weak and strong infusions prepared in a traditional way. The macronutrient content of black coffee is in accordance with data from other FCDBs, confirming it to be of low-energy value and a modest contribution to the dietary intake of macronutrients. At the same time, consuming 200 mL (2 cups) of a strong infusion per day could provide more than 7.5% of the daily reference intake of potassium. The obtained results for caffeine and CGA in the investigated coffee infusions highlight the generally high daily consumption of these biologically active non-nutrient compounds among the Serbian population.     

Differences in nutrient intake during a Greek Orthodox Christian fasting and non-fasting week, as assessed by a food composition database and chemical analyses of 7-day weighed food samples

This study aimed to assess the differences in nutrient composition of two diets, as estimated by a food composition database developed at the University of Crete, Greece, and by chemically analyzing duplicate portions of the diets. For this purpose, one healthy monk was asked to collect all foods consumed during a fasting (as indicated by Greek Orthodox Christian rituals) and a non-fasting week. Weekly samples were homogenized and frozen for chemical analysis. At both fasting and non-fasting weeks, food consumption was recorded using 7-day weighed food records. The food composition database provided a rough estimate of dietary intake, since differences greater than 15% between the two methods were found in both diets for total fat, dietary fibre, dietary cholesterol, plant sterols, iron, sodium and vitamins E and B-12. The discrepancies between the two methods can be minimized by regularly updating the food composition database and by incorporating reliable nutrient values for local foods. This will improve the reliability of studies examining the effect of dietary patterns on health, allow nutrient and dietary pattern comparisons and data exchange between countries and permit the incorporation of the nutrient composition of local products in European food composition networks.     

黄曲霉毒素高效液相色谱检测方法研究进展

近10年来，测定食品中黄曲霉毒素的高效液相色谱法(HPLC)得到了不断改进和提高，尤其是黄曲霉毒素特异性抗体的获得、免疫亲和柱的应用、荧光增强技术的提高以及样品处理和分析自动化技术的发展使HPLC法成为最主要的检测方法，本文综述了HPLC方法的研究进展。     

Determination of free quinic acid in food matrices by Hydrophilic Interaction Liquid Chromatography with UV detection

A new method using Hydrophilic Interaction Liquid Chromatography and UV detection was developed for the determination of free quinic acid in fourteen commercial beverages (fruit juices, red wine, coffee, vinegar, and edible mushroom extract). Samples were directly injected into the HPLC system after dilution and centrifugation. All separations were carried out by gradient elution on a ZIC^®-cHILIC column, using an eluent consisting of acetonitrile and aqueous phosphate buffer at pH 6. Quinic acid eluted in 12 min as a symmetric peak well separated from all other peaks in the chromatograms. The total turnaround time per sample was 60 min. The method was validated using cranberry juice as model beverage matrix. Linearity was demonstrated on spiked juice between 200 and 600 μg/mL (r² = 0.999), and precision and accuracy were satisfactory (RSD ≤ 10% and recovery 100 ± 1%, respectively).The method was proven to be suitable for its purpose. Quinic acid levels ranged from undetectable (<15 μg/mL in red grape juice, elderberry juice, and in red wine vinegar) to 740 ± 30 μg/mL (in mushroom extract). The results were discussed in comparison with the previous reports on similar matrices using different HPLC separation modes.     

Central composite design of pressurised hot water extraction process for extracting capsaicinoids from chili peppers

Pressurised hot water extraction (PHWE) was applied to chilies in order to optimise extraction yield of capsaicinoids (capsaicin, dihydrocapsaicin, nordihydrocapsaicin, nonivamide). Determination of the optimum extraction procedure was performed by comparison of the yield of the extracts. Capsaicinoids content was determined by HPLC coupled with mass spectrometry. An optimisation study was performed using water as an extraction solvent at constant extraction pressure (20 MPa), extraction temperature ranging from 120 to 240 °C and static extraction time ranging from 5 to 60 min as independent variables. The optimum PHWE conditions for all response variables were estimated; however, PHWE conditions resulting in the highest recovery of capsaicinoids (20 MPa, 200 °C and 10 + 20 min of static extraction time) were chosen for comparison with a conventional Soxhlet extraction (SOX) in the case of seven chili pepper fruit samples (chili peppers of species Capsicum chinenses: Trinidad Scorpion Moruga, Jamaican Hot Red, and Yellow Habanero, chilies of species Capsicum annuum: Yellow Bedder, Ring of Fire, and Chiltepin, chili pepper Tabasco of species Capsicum frutescens) and three chili spices (ground spices from Trinidad Scorpion Moruga, Bhut Jolokia, and Fatalii Red, all of species Capsicum chinenses).     

Rapid preparative extraction and determination of major organic acids in honeysuckle (Lonicera japonica Thunb.) tea

In this study, ionic liquid based microwave-assisted extraction (IL-MAE) followed by high-performance liquid chromatography (HPLC) was developed for determination of major organic acids in honeysuckle tea. The results suggest that varying the anion and cation had significant effects on the preparative extraction efficiency; aqueous solution of [C₆mim]Br was selected as solvent. The optimized extraction parameters were obtained as follows: IL concentration 0.5 M, temperature 50 °C, solvent to material ratio 20:1 mL/g and duration 9 min. Moreover, principal component analysis (PCA) was used to analyze the significances of these factors for IL-MAE and their interactions, and IL concentration was proved to be the most significant parameter. Compared with conventional sample preparation method, the content of organic acids in analytical sample was enhanced about 1.5-fold using IL-MAE in a shorter duration. In addition, a kinetic model of the preparative extraction process was established to fit the experimental data (R² > 0.99). The proposed HPLC method was successfully applied for determination of 5 organic acids in honeysuckle tea. The present research supported necessary data for sample preparation and quality analysis of honeysuckle tea.     

加速溶剂提取-高效液相色谱法测定蜜饯中6种食品添加剂的含量

目的:建立了加速溶剂萃取技术提取-高效液相色谱分析蜜饯中苯甲酸、山梨酸、胭脂红、苋菜红、安赛蜜、糖精钠的方法。方法:优化了压力、温度、静态时间、循环次数等参数。加速溶剂萃取提取蜜饯中添加剂的条件是:萃取温度80℃,压力10.3 MPa,静态提取6 min。结果:6种添加剂在0.02 mg/L～50 mg/L范围均具有良好的线性,相关系数均大于0.999,检出限分别为4.7μg/L～7.8μg/L,回收率分别为89%～99%,RSD均小于5.0%。结论:实验结果表明,该方法灵敏度高,重现性好,准确度高,可满足食品中添加剂分析。     

食品中咖啡因含量的测定方法

目的:采用HPLC测定食品中咖啡因的含量。方法:根据样品类型采用不同的处理方法,以Symmetry ShieldRPC18柱为固定相,甲醇/水为流动相,检测波长为273 nm。结果:咖啡因与其它杂质均能达到基线分离,其色谱峰形好。咖啡因的浓度在0.006~0.12 mg/ml时与峰面积成良好的线性关系(Y=-1.39×105 3.40×107X,r=0.9995),平均回收率为94.5%~105%,方法精密度RSD为2.30%、2.60%和2.57%(n=6)。结论:所用方法简便、准确、重复性好,适用于食品中咖啡因的测定。     

Mineral content of Pakistani foods: An update of food composition database of Pakistan through indirect method

Analysis of nutrients to develop new or update food composition database is costly and time consuming. An alternate approach is to add the data on nutrients from existing literature using guidelines set by International Network of Food Data Systems (INFOODS). The currently available database for food composition in Pakistan is fairly old (2001) and thus, needs to be updated. In the present study mineral content of various foods from Pakistan was collected from existing literature and scrutinized against a set of criteria for inclusion in updated food composition database of Pakistan. Data for 37 food items with eight minerals (calcium, iron, zinc, phosphorus, magnesium, potassium, sodium and copper) fits under the criteria therefore is included in updated database for foods of Pakistan. Additionally, chromium, cobalt, cadmium, lead, nickel and manganese were also updated for 16 food items. Further, selected mineral content (iron, zinc, phosphorus and calcium) was compared with food composition Table of Pakistan (published in 2001). Comparison results showed that mineral content for most of the foods vary among two databases. The present study demonstrates feasibility of updating food composition databases thorough scientific reports on food products of a particular country.     

Methodology for assigning appropriate glycaemic index values to an Australian food composition database

We aimed to produce an updated Australian glycaemic index (GI) database based on a systematic method. GI values were assigned to the 3871 unique foods in an Australian food composition database. Following the method, 1124 (29%) foods had less than 2.5 g of available carbohydrates per 100 g and were assigned a GI of 0, and 416 (11%) foods had a direct match in one of the three data tables used. The GI value of a ‘closely related’ food was assigned to 1793 (46%) foods; 135 foods (3%) had their GI values calculated using the weighted average GI method; 391 (10%) foods were assigned the median GI of their corresponding food subgroup, and 12 (<1%) foods were assigned a GI of 0 because they were not significant sources of carbohydrates in a typical diet. For the 3634 foods which received a GI value in the 2009 assignment, 1954 (53.8%) had an updated GI value, and the mean ± SD difference between the 2009 and current assigned values was +3.0 ± 16.0 units (paired sample t-test p < 0.001). Acknowledging some limitations, this database will enhance the utility of the GI concept in research and clinical settings in Australia (199 words).     

Computer-generated vegan menus: The importance of food composition database choice

Precise data on food chemical composition is crucial for any quantitative nutrition research and indispensable for evaluation and planning of computer-based menus. Moreover, exact food chemical composition is of the utmost importance in composing specific diets that may be low in certain essential nutrients. Therefore, this research evaluated a weekly vegan menu using three different food composition databases (FCDB): the Croatian, the official Danish Food Composition Database and the United States Department of Agriculture (USDA) – National Nutrient Database for Standard Reference. Significant differences (p < 0.05) were determined in evaluated and optimised offers for the same menu when using different FCDBs. Furthermore, in these menus quantities of some nutrients have not reached official daily recommendations needed for prevention of non-communicable diseases. In this research, new vegan menus that can provide adequate quantity of essential nutrients, regardless of FCDB utilized, were created with linear optimisation (LO). This resulted in high quality daily menu offers. However, depending on the FCDB that was used, optimal menus differed in daily meal combinations, and the effectiveness of the optimisation in the minimisation of differences caused by differences of data in FCDBs was tested. Linear optimisation has been proved to be an effective tool in planning of specific diets, such as vegan diets. Nonetheless, the quality of computer-planned menus depends heavily on the quality of FCDB used.