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MALDI-TOF mass spectrometry of oligomeric food polyphenols.

The structural heterogeneity of polyphenols from cranberries, grape seed extracts, sorghum and pomegranate was characterized by MALDI-TOF MS. Polyphenolics were isolated by liquid chromatography and subjected to MALDI-TOF MS using trans-3-indoleacrylic acid as the matrix. Spectrometric analysis gave information on degree of polymerization, monomeric substitution, and the nature of intermolecular bonds. Cranberry polyflavan-3-ols had variation in interflavan bonds (A- and B-types) and contained polyflavan-3-ols linked to anthocyanins through a CH3-CH bridge. Polygalloyl-polyflavan-3-ols in grape seed extract had large variation in the degree of galloyl substitution. Sorghum polyflavans had structural heterogeneity in glycosylation and hydroxylation. Pomegranate hydrolyzable tannins that correspond to previously described structures were detected, such as punicalagin, but others that correspond to oligomeric ellgitannins in which two to five core glucose units are cross-linked by dehydrodigalloyl and or valoneoyl units were also observed. Results demonstrate that large heterogeneity occurs in degree of polymerization, intermolecular bonds, pattern of hydroxylation, and substitution with monosaccharides and gallic acid.

Flavonoids↗

Effect of anorexic drugs on food intake and the micro-structure of eating in human subjects.

Human volunteer subjects of normal weight received oral doses of (+)amphetamine (10 mg) or (+/-)fenfluramine (30 mg and 60 mg) together with a placebo control according to a within-subjects design. The effects of these treatments were monitored by measuring food intake in a test meal, subjective ratings of hunger motivation and the micro-structure of eating behaviour abstracted from videotaped recordings of the test meal. Various measures of the rate of feeding were computed from these recordings. Amphetamine and fenfluramine (60 mg) showed generally similar effects on food intake and on the subjective experience of hunger, but displayed differing actions on the fine structure of eating. Amphetamine increased latency to initiation of eating and increased the rate of food ingestion, whilst fenfluramine slowed the local rate of eating and eliminated the characteristic decline in the rate of feeding across the course of a meal. These findings display certain resemblance to the results of animal experiments involving similar pharmacological manipulations and emphasise the importance of measuring rate of feeding in animal and human studies. The results of this study suggest that the micro-analysis of feeding behaviour not only provides a tool for understanding systems involved in the modulation of food consumption but also reveals information which may be helpful for the use of drugs in the treatment of obesity.

Adult↗

The use of structure-activity relationship analysis in the food contact notification program.

Food contact substances (FCS) include polymers, paper and paperboard, and substances used in their manufacture, that do not impart a technical effect on food. Moreover, FCSs are industrial chemicals generally consumed at dietary concentrations (DC) of less than 1mg/kg food (ppm), and more commonly at less than 0.05 ppm (50 ppb), in the daily diet. As such, many industrial chemicals have been analyzed for toxicological concern, some of which may share structural similarity with FCSs or their constituents, and the majority of these studies are available in the public domain. The DCs of these compounds lend themselves to using structure-activity relationship (SAR) analysis, as the available "expert systems" and use of analogs allows for prediction and management of potential carcinogens. This paper describes the newly implemented food contact notification (FCN) program, the program by which FDA reviews FCSs for safe use, the administrative review of FCSs, the SAR tools available to FDA, and qualitative and quantitative risk assessments using SAR analysis within the regulatory framework of reviewing the safety of FCSs.

Carcinogenicity Tests↗

Structural determination of unknown subsidiary colors in commercial food red Nos. 2 and 102.

Major subsidiary colors A (Sub A) and B (Sub B) in commercial Food Red No. 102, and colors C (Sub C) and D (Sub D) in commercial Food Red No.2 were isolated. These structures were characterized by physicochemical evidence. The structures of Sub A, B, and C are trisodium salt of 7-hydroxy-8-(6-sulfonaphthyl-2-azo)-1,3-naphthalenedisulfonic++ + acid, disodium salt of 4-amino-3-(4-sulfonaphthyl-1-azo)-1-naphthalenesulfonic acid and trisodium salt of 3-hydroxy-4-(6-sulfonaphthyl-2-azo)-2,7-naphthalenedisulfonic++ + acid, respectively. Sub D was identified as Sub B.

Amaranth Dye↗

Fine-scale genetic structure of life history stages in the food-deceptive orchid Orchis purpurea.

In natural plant populations, fine-scale spatial genetic structure can result from limited gene flow, selection pressures or historical events, but the role of each factor is in general hard to discern. One way to investigate the origination of spatial genetic structure within a plant population consists of comparing spatial genetic structure among different life history stages. In this study, spatial genetic structure of the food-deceptive orchid Orchis purpurea was determined across life history stages in two populations that were regenerating after many years of population decline. Based on demographic analyses (2001-2004), we distinguished between recruits and adult plants. For both sites, there was no difference in the proportion of polymorphic loci and expected heterozygosity between life history stages. However, spatial autocorrelation analyses showed that spatial genetic structure increased in magnitude with life history stage. Weak or no spatial genetic structure was observed for recruits, whereas adult plants showed a pattern that is consistent with that found in other species with a predominantly outcrossing mating system. The observed differences between seedlings and adults are probably a consequence of changes in management of the two study sites and associated demographic changes in both populations. Our results illustrate that recurrent population crashes and recovery may strongly affect genetic diversity and fine-scale spatial genetic structure of plant populations.

Flowers↗

Rat muscle structure and metabolism in relation to age and food intake.

Age changes in oxygen consumption and the structural composition of the lateral omohyoideus muscle were studied in adult male rats. The rate were either fed ad libitum (group A) or 60% of the ad libitum intake (group R). An age-related loss in muscle mass did not occur even at advanced ages in group A or group R rats. Muscle fiber diameter decreased with age in both groups but a concomitant increase in the number of fibers prevented a change in muscle mass. The muscles of group R rats contained the same number of fibers as those of group A rats at all ages. The muscles of group A rats showed a progressive loss in rate of resting oxygen consumption until 18 mo of age. A similar but less marked loss in oxygen consumption occurred in the muscles of group R rats. These results provide further evidence that life-prolonging food restriction modulates physiological changes associated with the aging process.

Aging↗

The structure and interactions of starch with food constituents.

For most starch-containing foods, the physical and functional properties can be traced to characteristic molecular species being present, their interactions with each other, and modifications caused by environmental conditions (moisture, temperature, shear) during processing and storage. In the present paper, the chemistry and physical chemistry of starch are discussed with an emphasis on how structure (molecular and supermolecular) and composition influence the functionality of this polysaccharide. New experimental findings brought forward on structure indicate that this polymeric carbohydrate is found in various metastable states, depending on the thermomechanical history of the product. Even more important to processing and quality attributes of starch products is the recognition that the dynamics of the supermolecular structure and interactions between starch and other food constituents are governed by the mobility of the amorphous phase of each particular system. In this respect, water, acting as a plasticizer, depresses the glass transition temperature (Tg) and thereby alters the kinetics of state transformations (e.g., gelatinization, retrogradation) and reactivity of starch. The effects of water on phase transition behavior of starch as well as the underlying molecular mechanisms to the phenomena of gelatinization, gelation, retrogradation, and starch-lipid interactions are reviewed herein. Finally, consideration is given to factors affecting the digestibility of starch from the viewpoint of processing-related changes in the susceptibility of starch to alpha-amylase.

Food Analysis↗

[Escherichia coli enterotoxins--their significance for food hygiene and recent findings on the structure and mode of action (review)].

Enterotoxin-forming Escherichia (E.) coli germs may be a cause of food poisoning. Any assessment of E. coli in various types of foodstuff together with an appraisal of its relevance to food hygiene will be of inadequate reliability unless virulence properties of germs are investigated, as well. No comprehensive evaluation can be made of quantitative occurrence of food poisoning caused by enterotoxigenic E. coli strains. Literature data are now being compiled on the occurrence of such strains in food items and on the incidence of intoxications. Reference is made in great detail to recent findings on structure and mode of action of heat-labile and heat-stable enterotoxins of E. coli.

Enterotoxins↗

Cleavage of hemoglobin by hookworm cathepsin D aspartic proteases and its potential contribution to host specificity.

Hookworms routinely reach the gut of nonpermissive hosts but fail to successfully feed, develop, and reproduce. To investigate the effects of host-parasite coevolution on the ability of hookworms to feed in nonpermissive hosts, we cloned and expressed aspartic proteases from canine and human hookworms. We show here that a cathepsin D-like protease from the canine hookworm Ancylosotoma caninum (Ac-APR-1) and the orthologous protease from the human hookworm Necator americanus (Na-APR-1) are expressed in the gut and probably exert their proteolytic activity extracellularly. Both proteases were detected immunologically and enzymatically in somatic extracts of adult worms. The two proteases were expressed in baculovirus, and both cleaved human and dog hemoglobin (Hb) in vitro. Each protease digested Hb from its permissive host between twofold (whole molecule) and sixfold (synthetic peptides) more efficiently than Hb from the nonpermissive host, despite the two proteases' having identical residues lining their active site clefts. Furthermore, both proteases cleaved Hb at numerous distinct sites and showed different substrate preferences. The findings suggest that the paradigm of matching the molecular structure of the food source within a host to the molecular structure of the catabolic proteases of the parasite is an important contributing factor for host-parasite compatibility and host species range.

Ancylostomatoidea↗

[Advances in research on biosynthesis of plant amylopectin].

Amylopectin, accounting for 70%-80% of storage starch, is one of the key components for quality of fruits and seeds in plant. Research on biosynthetic pathway of plant amylopectin holds great promise for modifying the structural composition of amylopectin and being used in food industry. The structure of plant amylopectin is summarized in this review and three types of amylopectin synthetase: starch branching enzyme (SBE), soluble starch synthase (SSS) and starch debranching enzyme (SDBE), which have become hotspots for research now, are expatiated in terms of genetics, enzymology and function. A model for the synthesis of amylopectin, "two-step branching and improper branch clearing model" is discussed. Problems in plant amylopectin biosynthesis and prospects for its application are also presented.

1,4-alpha-Glucan Branching Enzyme↗

Regulations on statements made for dietary supplements concerning the effect of the product on the structure or function of the body. Food and Drug Administration, HHS. Final rule.

The Food and Drug Administration (FDA) is issuing final regulations defining the types of statements that can be made concerning the effect of a dietary supplement on the structure or function of the body. The regulations also establish criteria for determining when a statement about a dietary supplement is a claim to diagnose, cure, mitigate, treat, or prevent disease. This action is intended to clarify the types of claims that may be made for dietary supplements without prior review by FDA and the types of claims that require prior authorization as health claims or prior approval as drug claims.

Body Composition↗

A prototype model structure for mixed microbial populations in homogeneous food products.

An important factor which has not been included in many models in the field of predictive microbiology is the influence of a background of microflora in a food product. It is however generally known that the growth of a microorganism as a pure culture can be substantially different from its growth in a mixed culture, due to microbial interactions. Because of the importance of these interactions and the lack of suitable modeling techniques in the field of predictive microbiology to describe them, the potential of models in other research fields-namely ecology-to deal with interactions is explored in previous work of the authors. However, a model structure for microbial growth in food products cannot simply be copied from those elaborated in ecology. The structure of a predictive growth model is indeed typical, primarily due to the explicit modeling of a lag phase. The current paper proposes a prototype model structure for growth of mixed microbial populations in homogeneous food products. The model is able to describe a lag phase and reduces to a classical predictive growth model in the special case of single-species growth.

Bacteria↗

Size-dependent interactions inhibit coexistence in intraguild predation systems with life-history omnivory.

Growth in body size during ontogeny often results in changes in diet, leading to life-history omnivory. In addition, growth is often dependent on food density. Using a physiologically structured population model, we investigated the effects of these two aspects of individual growth in a system consisting of two size-structured populations, an omnivorous top predator and an intermediate consumer. With a single shared resource for both populations, we found that life-history omnivory decreases the likelihood of coexistence between top predator and intermediate consumer in this intraguild predation (IGP) system. This result contrasts with previous unstructured models and stage-structured models without food-dependent development. Food-dependent development and size-dependent foraging abilities of the predator resulted in a positive feedback between foraging success on the shared resource at an early life stage and foraging success on the intermediate consumer later in life. By phenomenologically incorporating this feedback in an unstructured IGP model, we show that it also demotes coexistence in this simple setting, demonstrating the robustness of the negative effect of this feedback.

Animals↗

European food and nutrition policies in action. Finland's food and nutrition policy: progress, problems and recommendations.

Some progress has clearly been made in several aspects of Finland's food and nutrition policy: access to nutrition information and education, improvements in mass catering, increased availability of healthier food products, and pricing and quality requirements favourable to a healthy diet. Finnish eating patterns have improved in relation to some recommended foods and macronutrients. The structural changes in farm and food production are largely the result of new political and economic realities both in Finland and internationally, resulting in the Government focusing on fiscal efficiency, decentralization and a more competitive, consumer-oriented market. This new environment is creating pressures to reduce surplus animal fat production and to expand markets in new foods for Finns and other Europeans who, for reasons of demography, health or working or living arrangements, demand new and sometimes healthier foods. Within this context, some health leaders have been able to make and work for proposals that are consistent both with political and economic imperatives and with health needs. Although the populations health status is improving and in some respects is exemplary, diet-related death and illness rates and risk factors (such as serum cholesterol and obesity) are high and their decline, along with some healthy changes in eating patterns, has slowed since the mid-1980s (ironically, since the adoption of the nutrition policy). The more slowly improvements occur, the higher will be the social and economic costs. Major problems in policy implementation exist. Although much has been done in research and demonstration and in the development of national guidelines (in public catering and labeling, for example) there is an apparent lag in translating such soft technology into action and monitoring its implementation in order to develop corrective measures at the operational level. This problem may increase with decentralized budget control and a less regulated market, where listening to the consumer (whether an individual, retailer or caterer) may not necessarily result in healthier products are more accurate consumer information, especially as foreign products and media continue to attract Finnish young people. The lack of a leading strategic body that can authoritatively assess and anticipate problems in implementation, deal with them and coordinate and monitor the necessary action in fundamental to these issues. Rapid progress in economic and farm policy development and food enterprises can provide conditions supportive of health and nutrition goals if such interests are systematically taken into account and allowed to moderate potential negative changes. If it is to be effective, such accounting will require initiative, clarity of strategic purpose and organization by health and nutrition leaders.

Finland↗

Bacterial community structure in kimchi, a Korean fermented vegetable food, as revealed by 16S rRNA gene analysis.

Kimchi is a traditional Korean food fermented from a variety of vegetables. We elucidated the microbial community structure of five commercially produced kimchis made from Chinese cabbage by examining culture-independent 16S rRNA gene clone libraries. Most of the clones (347 out of 348) belonged to lactic acid bacteria and included several species of the genera Lactobacillus, Leuconostoc and Weissella. Weissella koreensis was found in all the samples and predominated in three of them (42.6-82%). Leuconostoc gelidum, Leuconostoc gasicomitatum and Lactobacillus sakei were common in the remaining kimchi clone libraries (>34%). The composition of bacterial phylotypes in kimchi varied between samples. Our approach revealed different community structures from those reported in previous culture-dependent studies based on phenotypic identification methods. The culture-independent method used here proved to be efficient and accurate and showed that the bacterial communities in kimchi differ from those in other fermented vegetable foods.

Base Sequence↗

Food webs: experts consuming families of experts.

Food webs of habitats as diverse as lakes or desert valleys are known to exhibit common "food-web patterns", but the detailed mechanisms generating these structures have remained unclear. By employing a stochastic, dynamical model, we show that many aspects of the structure of predatory food webs can be understood as the traces of an evolutionary history where newly evolving species avoid direct competition with their relatives. The tendency to avoid sharing natural enemies (apparent competition) with related species is considerably weaker. Thus, "experts consuming families of experts" can be identified as the main underlying food-web pattern. We report the results of a systematic, quantitative model validation showing that the model is surprisingly accurate.

Animals↗

Rheology of dairy foods that gel, stretch, and fracture.

Casein gels are found in hard and soft dairy foods such as cheese and yogurt, and their rheological properties can be analyzed with various instrumental techniques. Empirical tests of cheese have been used since cheese making began, and imitative tests have been conducted in laboratories since the 1930s. Texture profile analysis is now the most frequently used imitative test. Fundamental tests provide a better representation of cheese and yogurt rheology because of the systematic mathematical treatment involved. Uniaxial compression and stress and strain relaxation tests are among the fundamental tests performed on cheese, and viscosity data are often used to investigate the physical characteristics of yogurt. Small amplitude oscillatory shear measurements are applicable to both products. Food scientists can acquire a clearer picture of the structure of dairy foods by performing appropriate rheological studies of the casein matrix.

Caseins↗