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At least 397 records · Page 22Linked to original sources
PubMed2002

Fractal analysis of ice crystals in frozen food.

Fractal analysis of the morphology of ice crystal particles in frozen food was attempted for frozen soybean curd (tofu). From a microscopic image analysis of the ice crystal particles, it was found that the perimeter of the ice crystal particles could be recognized as a fractal. Effects of the storage time and storage temperature on the fractal dimension (d(p)) of the perimeter of the ice crystal particles were also investigated. As storage time was increased, the d(p) value tended to decrease. When the storage temperature was increased, the value of d(p) decreased more rapidly. The changes corresponded to the visual observation of the shape change for the ice crystal particles during storage reported by many researchers, suggesting that the fractal dimension d(p) could be used as a quantitative indicator reflecting the surface roughness of ice crystal particles.

Crystallization↗
PubMed2000

MALDI-TOF MS analysis of isoflavones in soy products.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a new technique having a number of advantages for food analysis. This study is the first to demonstrate the use of MALDI-TOF MS to identify isoflavones in soy samples. 2',4',6'-Trihydroxyacetophenone (THAP) and 2,5-dihydroxybenzoic acid (DHB) were both good matrices for isoflavones, but DHB was chosen as the best because it worked well for sample extracts, with good spot-to-spot repeatability. Isoflavones were predominantly ionized in a protonated form with a very small amount of sodium or potassium adduct ions. Fragmentation occurred only through loss of glycosidic residues. Daidzin showed more than twice the response of genistin using MALDI-TOF MS. A simple solid phase extraction of isoflavones from soy samples was developed for MALDI-TOF MS analysis. MALDI-TOF MS can provide an isoflavone profile in 2 min and serves as a powerful tool to identify and study processing changes of isoflavones in soy products.

Food Analysis↗
PubMed1999

Vitamin K: a practical guide to the dietary management of patients on warfarin.

Warfarin has been successfully used in the medical management of thromboembolic disease for nearly six decades. It is widely assumed that a dietary vitamin K-warfarin interaction exists. To avoid this potential interference with the efficacy of warfarin in stable anticoagulation, patients typically receive instructions to consume a constant dietary intake of vitamin K. While dark, green vegetables are primary sources of dietary vitamin K, these foods are not commonly consumed on a daily basis in the United States. However, there still exists dietary resistance to warfarin that is attributable to vitamin K. Based on food analysis studies on vitamin K, it is now known that dietary vitamin K is found in certain plant oils and prepared foods containing these plant oils, such as baked goods, margarines, and salad dressings. The preparation of foods with vitamin K-rich oils may also contribute to a diet-warfarin interaction, although this has yet to be confirmed in a clinical trial. A dose-response of vitamin K on the effect of warfarin anticoagulation has not yet been established. However, there are sufficient data to suggest that a constant dietary intake of vitamin K that meets current dietary recommendations of 65-80 micrograms/day is the most acceptable practice for patients on warfarin therapy. Vitamin K composition data for commonly consumed foods are now available and may facilitate successful anticoagulation for patients being treated with warfarin.

Anticoagulants↗
PubMed2006

Recent advances in amino acid analysis by capillary electrophoresis.

This paper describes a number of articles that have been published on amino acid analysis using CE during the period from June 2003 to May 2005. This review article follows the previous ones of Smith (Electrophoresis 1999, 20, 3078-3083), Prata et al. (Electrophoresis 2001, 22, 4129-4138), and Poinsot et al. (Electrophoresis 2003, 24, 4047-4062). Several new developments in amino acid analysis with CE are reported concerning UV detection, LIF, MS, and NMR. In addition, we describe articles concerning clinical and pharmaceutical studies, neuroclinical applications, and agricultural and food analysis.

Amino Acids↗
PubMed2006

Dietary exposure of children and teenagers to benzoates, sulphites, butylhydroxyanisol (BHA) and butylhydroxytoluen (BHT) in Beirut (Lebanon).

The acceptable daily intake (ADI) for a considered chemical is by definition the amount of that substance which can be ingested every day during the life time without appreciable health risk. The theoretical risk of exceeding the ADI for benzoates, sulphites, butylhydroxyanisol (BHA) and butylhydroxytoluen (BHT) has often been examined on the basis of worst case scenario. The aim of this paper is to assess the actual intake of the food additives listed above for a group of the Lebanese population (students aged between 9 and 18 years old) likely to be highly exposed to food additives through the consumption of processed foods. Dietary exposure was obtained by combining food consumption data with food additives levels determined by chemical analysis. Food products available in Lebanon and containing added benzoates, sulphites, BHA and BHT were identified. Overall 420 samples of foods and beverages were analysed. The determination of food additives residue levels was carried out according to the official methods adopted in "Lebanese Institute for agronomic research" (IRAL) on food as consumed. The acceptable daily intake (ADI) could be exceeded for sulphites and BHT by a fraction of the population, in particular within children of 9-13 years old. Among all food additive-containing foods, the highest contributors were: soft drinks to benzoates intake, nuts and canned juices to sulphites intake, bread and biscuits to BHA intake and chewing gum to BHT intake.

Adolescent↗
PubMed1997

INFOODS: the international network of food data systems.

A 1983 conference organized by United Nations University proposed an international network of food data systems (INFOODS) to address the need for and limitations of food-composition databases. Concerns of INFOODS include the acquisition and interchange of quality data on the nutrient composition of foods; the development of standards and guidelines for the collection, compilation, and reporting of food-component information; and support of a worldwide network of regional data centers for the generation, compilation, and dissemination of information on food composition. One goal of these centers is to assist in the development of appropriate national databases, especially in developing countries. Much has been accomplished by INFOODS, despite limited resources. Several important documents on food composition have been published, an international journal of food composition has been established, a directory of existing food-composition databases has been compiled, specific recommendations for the construction and use of food-composition databases have been developed, and a system of food nomenclature and coding has been created. Regional food-composition databases have been established throughout the world, with the goal of creating computerized systems that permit easy availability and interchange of food-composition data between regions and countries. In 1993 the Food and Agriculture Organization renewed its interest in the food-analysis capability of developing countries by becoming involved in INFOODS efforts.

Databases, Factual↗
PubMed2003

[Progress in the studies on new derivative atomic spectrometry].

Progress in the studies on new derivative atomic spectrometry was reviewed. Models of conventional atomic spectrometric signals and derivative atomic spectrometric signals were described. Basics and characteristics of the derivative atomic spectrometry based on the variety of signal intensity with time were discussed. Applications of the derivative atomic spectrometry to biological, environmental, pharmaceutical and food analysis with higher sensitivity and lower detection limit were described.

Biological Products↗
PubMed1985

A comparative study of two nutrient data bases.

Reported dietary intake records of 18 infants, 22 young children, and 20 women were analyzed using the nutrient data base systems of the Second National Health and Nutrition Examination Survey (NHANES II) and the Nutrient Dietary Data Analysis (NDDA) System. Significant differences between the nutrient data bases were found in the calculations of potassium and niacin for infants and of energy and nine nutrients for women and children. The energy and nutrient composition of many commonly consumed food items in the two nutrient data base systems was different, even though the systems shared common data sources. Differences in the nutrient data bases were primarily due to the timing of data base updates, as well as to the differential use of industry, private, and government food analysis sources, procedural differences in data base updating, and random data entry error. Resolution of differences among nutrient data base systems may depend upon comprehensive reviews of all data base systems or the establishment of a national nutrient data base to serve as a standard for the professional.

Child, Preschool↗
PubMed1999

Comparison of 4 nutrient databases with chemical composition data from the Dietary Approaches to Stop Hypertension trial. DASH Collaborative Research Group.

Accuracy of computerized nutrient databases is an important consideration in selecting a nutrient analysis system. We project compared the nutrient content of daily menus calculated from 4 microcomputer programs to chemical analysis of menus analyzed for the Dietary Approaches to Stop Hypertension (DASH) trial. Thirty-six menus were entered at 2 independent DASH sites using the ESHA Food Processor, Minnesota Nutrition Data System, Moore's Extended Nutrient Database, and Nutritionist IV databases. Food prepared according to these menus was chemically analyzed at the Food Analysis Laboratory Control Center at Virginia Polytechnic Institute and State University, Department of Biochemistry, Blacksburg. Estimates for 13 nutrients were compared: energy, total fat, saturated fat, monounsaturated fat, polyunsaturated fat, carbohydrate, protein, cholesterol, calcium, potassium, magnesium, iron, and sodium. The overall intraclass correlation between the 2 sites' data entry was 0.998; thus, values were averaged for analyses. Databases varied significantly in their mean deviations from chemical analyses values for saturated, monounsaturated, and polyunsaturated fatty acids, potassium, magnesium, and iron (P < .05); however, these differences were small (< 10%). Absolute deviations, which estimate the combined effect of bias and precision, were significantly different among databases for energy, saturated fatty acids, and polyunsaturated acids. Absolute differences from the laboratory values varied by < 15%, except for iron. All 4 databases were comparable in accuracy and precision and performed well. Criteria for database selection depends not only on overall database accuracy, especially for nutrients of interest, but also on the ease of use of the program, relevant features of the associated software; and cost.

Blood Pressure↗
PubMed2004

Dietary patterns and risk of gastric cancer: a case-control study in Uruguay.

BACKGROUND: Gastric cancer is a frequent malignancy in the Uruguayan population. In northern counties, incidence rates reach high figures (age-standardized rates [ASR], 37.3 per 100,000 men and 18.3 per 100,000 women). Diet is a major determinant in gastric carcinogenesis. Because foods or food groups have the advantage over nutrients in being most directly related to dietary recommendations, we decided to conduct a case-control study on the relationships between food groups and risk of gastric cancer. For this purpose, we included 240 cases and 960 controls. METHODS: In the present study we employed three analytical approaches: (1) individual food group analysis, (2) factor analysis, and (3) analysis of empirical scores of risk. Individual analysis of food groups was performed by multiple unconditional logistic regression, with food groups being the explanatory variables. Nineteen food groups were created and categorized in tertiles according to the control distribution. Factor analysis aggregated intercorrelated foods in broader eating patterns. In this study we were able to identify three factors or patterns, arbitrarily labeled "starchy," "healthy," and "mixed." Finally, empirical scores of risk were created after examining the risk of each individual food and summing each significant item. This resulted in a risk enhancing score and a protective score. Both scores were categorized in tertiles according to the control distribution. RESULTS: The individual analysis of food groups showed increased risks of gastric cancer for rice, salted meat, stewed meat, white bread, potatoes, and tubers. On the other hand, raw vegetables, total fruits, legumes, and black tea were inversely associated with risk of gastric cancer. All three dietary patterns, generated by factor analysis, were significantly associated with gastric carcinoma risk. Whereas the starchy factor was directly associated with gastric cancer, the healthy and mixed patterns were strongly protective. Finally, the risk enhancing empirical score displayed an increased risk of gastric cancer (odds ratio [OR], 4.1, 95% confidence interval [CI], 2.6-6.6), whereas the protective score showed an important reduction in risk, of 0.38. CONCLUSION: This study displayed consistent results from three different approaches. Concerning different food groups, stewed and processed meat are rich in salt; rice, tubers, and winter squash are sources of starch; and vegetables and fruits are rich in ascorbic acid and carotenoids. All these substances have been strongly related to gastric carcinogenesis. Furthermore, this study suggests that diets rich in vegetables and fruits and with low amounts of salty and starchy foods are recommendable for the prevention of gastric cancer.

Adult↗
PubMedDate not supplied

Revalidation and long-term stability of National Institute of Standards and Technology Standard Reference Materials 1566, 1567, 1568, and 1570.

Multiple units of Standard Reference Materials (SRMs) 1566 Oyster Tissue, 1567 Wheat Flour, 1568 Rice Flour, and 1570 Trace Elements in Spinach, produced by the National Institute of Standards and Technology (NIST, then the National Bureau of Standards), were analyzed 17-20 years after the original certification dates and 12-15 years after the certificates became invalid. Instrumental neutron activation analysis and thermal neutron prompt gamma-ray activation analysis were used to measure mass fractions for 27 elements in these SRMs to revalidate them for use in quality assurance (QA) programs required for food analysis programs within the U.S. Food and Drug Administration. With the exception of Se in SRM 1567, all element mass fractions were in agreement with certified values and literature data. Some evidence of B loss from SRM 1568 was observed. These materials were judged to be suitable for continued use in QA programs. Findings showed that these matrixes exhibited stability of moisture, mass fraction, and weight basis for far longer (> or =15 years) than was indicated by the 5-year validity statement on the NIST Certificates of Analysis.

Animals↗
PubMed2004

Solid-phase microextraction: a powerful sample preparation tool prior to mass spectrometric analysis.

Sample preparation is an essential step in analysis, greatly influencing the reliability and accuracy of resulted the time and cost of analysis. Solid-Phase Microextraction (SPME) is a very simple and efficient, solventless sample preparation method, invented by Pawliszyn in 1989. SPME has been widely used in different fields of analytical chemistry since its first applications to environmental and food analysis and is ideally suited for coupling with mass spectrometry (MS). All steps of the conventional liquid-liquid extraction (LLE) such as extraction, concentration, (derivatization) and transfer to the chromatograph are integrated into one step and one device, considerably simplifying the sample preparation procedure. It uses a fused-silica fibre that is coated on the outside with an appropriate stationary phase. The analytes in the sample are directly extracted to the fibre coating. The SPME technique can be routinely used in combination with gas chromatography, high-performance liquid chromatography and capillary electrophoresis and places no restriction on MS. SPME reduces the time necessary for sample preparation, decreases purchase and disposal costs of solvents and can improve detection limits. The SPME technique is ideally suited for MS applications, combining a simple and efficient sample preparation with versatile and sensitive detection. This review summarizes analytical characteristics and variants of the SPME technique and its applications in combination with MS.

Animals↗