Food utilization in relation to gut structure and function in wild and domestic birds and mammals.
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Animal Nutritional Physiological Phenomena↗
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Interaction between physical structure and amylose:amylopectin ratio of foods on postprandial glucose and insulin responses in healthy subjects.
OBJECTIVE: To study the effect of amylose content on postprandial glucose and insulin responses in healthy subjects by serving fixed amounts of simple starchy foods with a varying but strictly controlled water, fat and guar gum content. DESIGN: A blind, randomised, balanced cross-over study. SETTING: The kitchen of the Nutrition Research Unit in the Unilever Research Laboratorium. SUBJECTS: Apparently healthy employees of Unilever Research Laboratorium. INTERVENTIONS: Subjects consumed, after an overnight fast, either a drink (12 men), a pudding (6 men and 6 women), a roll without (5 men and 6 women) or a roll with guar gum (12 men) as breakfast and the same amount of the same food as mid-morning snack. Each subject consumed the experimental food prepared in four ways: either with high- or normal-amylose starch, and with or without added fat. At 30 and 90 min after consumption of the breakfast or the snack a blood sample was taken for determination of glucose and insulin. RESULTS: Raising the amount of amylose in starchy drinks and puddings, but not in rolls, lowered postprandial glucose and insulin responses. Fat addition to starchy drinks, puddings and rolls attenuated postprandial glucose responses, irrespective of the amount of amylose or guar gum present. Addition of guar gum to rolls reduced glucose and insulin responses. Glucose tolerance tended to be less after consumption of the experimental foods as mid-morning snack than after consumption as breakfast. CONCLUSION: The physico-chemical composition of foods does influence the effect of the amylose:amylopectin ratio in starchy foods on postprandial glucose and insulin responses.
Amylopectin↗
Progress in understanding the phylogeny of flagellates.
Heterotrophic free-living flagellates appear to provide the ancestry for all other eukaryote groups. Not only are the oldest surviving anaerobic eukaryotes flagellated protists, but also there appear to be survivors of a lineage of flagellate forms which could have been close to the sources of the main branches of eukaryote evolution. These 'stem' forms of flagellates developed more complex flagellation with anchoring fibres which became the main components of the cytoskeleton and supported the cytostome; by their phagotrophic activities these flagellates established symbiotic relationships, first with aerobic bacteria to form mitochondria, and later with various forms of prokaryotic and eukaryotic algal cells to form chloroplasts of a variety of types having different pigments, different structure and different food storage patterns. The specific patterns of flagellation, cytoskeleton, cytostome, secreted surface structures and cell aggregation into colonies enable groups of organisms to be recognised, whose most primitive survivors in almost all cases are heterotrophic flagellates. The current view of the phylogeny of eukaryotes suggests that heterotrophic flagellates have provided the origins of all major eukaryote groups, and that the phylogeny of these flagellates is the key to understanding the evolution of all eukaryotes. We anticipate that further rRNA analyses, supported by ultrastructural data, will confirm the central role played by these flagellates in eukaryote evolution.
Animals↗
NMR applications in complex food systems.
The rheological and functional properties of food components are related to their molecular structure, morphology, and atomic mobilities. NMR provides a powerful tool for elucidating chemical structures, molecular conformations, and interactions of components in food systems. Quantitative analysis of sugars, fats, and other principal compounds in complex food systems was achieved by high-resolution liquid NMR. In addition to information available from liquid experiments, solids NMR experiments can reveal differences and changes in crystal packing of structures in food model systems. Interpretation of experimental results is enhanced by molecular modeling of key food compounds. Models for fat crystallization are carried out to enhance understanding of the molecular structures involved in the fat crystallization process. Recently, MRI has also shown significant impact on food science and technology. Some examples of NMR applications are given in this presentation.
Crystallization↗
Evaluation of new anti-infective drugs for the treatment of selected infections of the skin and skin structure. Infectious Diseases Society of America and the Food and Drug Administration.
No method for classifying infections of the skin and skin structure is uniformly accepted. Therefore, each protocol for the evaluation of new anti-infective drugs must include definitions of the skin and skin-structure infections to be treated. Clinical findings may suggest the etiology. Cultures should be performed by the best available technique. Because the yield of pathogens from sites of skin and skin-structure infection is often low, monitoring of the clinical response to therapy is paramount. Randomized, double-blind, active-control comparative studies are needed, and maintenance of blinding is recommended, even with a change in the route of administration of the study and/or control drugs. The period of follow-up should be defined for each type of infection.
Anti-Infective Agents↗
Structural basis of the genotoxicity of nitrosatable phenols and derivatives present in smoked food products.
The CASE methodology for studying structure-activity relationships has been applied to investigating the basis of the genotoxicity of phenols and derivatives following exposure to nitrous acid. The structural features identified include availability of positions para or ortho to the hydroxyl groups, that one meta position must remain unoccupied and one ortho or para position must be unsubstituted as well. The analyses revealed that genotoxicity is dependent upon the ease of formation of the active phenyldiazonium intermediate and is influenced only secondarily by the nature of the genotoxicant or its ease of entry into the cell. With this data base, CASE predicts the genotoxicity, following nitrosation, of a number of agents, including serotonin, acetaminophen, and of some naturally-occurring pesticides present in edible plants.
Food Analysis↗
Effects of colony composition and food type on nutrient distribution in colonies of Monomorium orientale (Hymenoptera: formicidae).
Monomorium orientale Mayr (Hymenoptera: Formicidae) is a common structure- and food-infesting ant in Asia. There is only limited information on the biology and habits of this species, especially on the preferred foods and distribution of nutrients in colonies. We conducted a laboratory study on the distribution of carbohydrates, proteins, and lipids, which were represented by respective food sources, in M. orientale colonies. Three colony conditions were applied: normal, with a balanced ratio of castes, queenless (only workers and brood), and broodless (only queens and workers). Food sources were stained to track the flow of the respective food in the colonies. Results revealed that carbohydrates had rapid distribution, with > 60% of the colony indicated in 24 h, in all colony conditions. Queens in all colonies did not feed on protein. Protein showed a more delayed distribution in the brood in all colony conditions; < 10% of the colony fed on protein by 24 h. Only queens in broodless colonies showed signs of feeding on lipid, with < 10% indicated in 24 h. Workers in all colonies fed on lipid as soon as it was delivered, whereas the brood only began to reveal feeding response after 24 h.
Animal Nutritional Physiological Phenomena↗
Structural determination of unknown subsidiary colors in food yellow no. 5 (Sunset yellow FCF).
Major unknown subsidiary colors A (Sub A) and B (Sub B) in commercial Sunset Yellow FCF (Food Yellow No. 5 in Japan) have been isolated by preparative HPLC. Spectroscopic analyses of Sub A and Sub B revealed that their structures are trisodium salt of 6-hydroxy-7-(4-sulfophenyl)-5-(4-sulfophenylazo)-2-naphthale nesulfonic acid, and disodium salt of 3-hydroxy-4-(4-sulfophenylazo)-2-naphthalenesulfonic acid, respectively.
Azo Compounds↗
Estimation of radionuclide ingestion: the "PATHWAY" food-chain model.
This paper describes the structure of the dynamic food-chain model PATHWAY and its utility for estimating radionuclide ingestion after fallout deposition from nuclear testing in Nevada. Model input requirements are described and output examples are provided. The basic output of PATHWAY is the time-integrated radionuclide ingestion by humans per unit fallout deposition (Bq per Bq m-2). Output specific to sex, age, life-style (diet), location (agricultural practice), event (calendar date), and radionuclide may be generated. Uncertainties of model predictions, based on "Monte Carlo" simulations using parameter value distributions, are described. Results of a sensitivity analysis, based on a ranking of partial correlation coefficients, are reviewed to illustrate the relative importance of parameters and associated transport pathways. Output data for 131I and 137Cs in milk are compared with predictions from several well known food-chain models. Preliminary efforts to validate PATHWAY results with real data sets are described.
Adolescent↗
[Lactose--a potential dietary fiber. The regulation of its microecological effect in the intestinal tract. 1. Problems, state of knowledge and methods].
Food components of different chemical structure which attain the colon without being attacked by digestion and absorption during their transit through the small intestine are defined as dietary fibre. In the colon they serve as energy or nutrient source for the intestinal microflora or are excreted without change. Not only chemical structure is decisive when a food component has to be assigned to either nutrients or dietary fibre: Substances resisting small intestine digestion due to the lack of corresponding catabolizing enzymes in man are supposed to be "obligate" dietary fibre. "Potential" dietary fibre are nutrients which are only partially digested in the small intestine. Lactose--the main carbohydrate of milk--represents a typical potential dietary fibre. The present paper investigates the factors being responsible for both the degree of lactose utilization in the small intestine and its efficiency in the colon.
Animals↗
[Energy expenditures and the actual nutrition of workers in a synthetic leather plant].
A study was made of energy expenditures and factual nutrition of the workers engaged in synthetic leather manufacture. Antropometric measurements were also taken. Based on the study of daily energy expenditures, the calculations were made of the optimal requirements of the main substances and energy. The actual nutrition of the workers was found to provide the necessary caloricity covering energy expenditures. However, definite shortcomings were revealed in the structure of the foods consumed, namely insufficient intake of vegetable fats, the prevalence of simple sugars in the structure of carbohydrate component, insufficient intake of vitamins A, B1 and folacin. According to the antropometric measurements 30,4% of the examined workers were obese.
Adult↗
A conceptual model of the food and nutrition system.
The food system is a widely used concept, but few systematic frameworks model the full scope and structure of the food and nutrition system. Bibliographic searches, a modified Delphi technique, focus groups and interviews with experts on the topic were conducted to identify existing models of agriculture, food, nutrition, health and environmental systems. These models were examined, classified and synthesized into an integrated conceptual model of the food and nutrition system. Few existing models broadly described the system and most focused on one disciplinary perspective or one segment of the system. Four major types of models were identified: food chains, food cycles, food webs and food contexts. The integrated model developed here included three subsystems (producer, consumer, nutrition) and nine stages (production, processing, distribution, acquisition, preparation, consumption, digestion, transport, metabolism). The integrated model considers the processes and transformations that occur within the system and relationships between the system and other systems in the biophysical and social environments. The integrated conceptual model of the food and nutrition system presents food and nutrition activities as part of a larger context and identifies linkages among the many disciplines that deal with the food and nutrition system.
Agriculture↗
Mutational epitope analysis of Pru av 1 and Api g 1, the major allergens of cherry (Prunus avium) and celery (Apium graveolens): correlating IgE reactivity with three-dimensional structure.
Birch pollinosis is often accompanied by adverse reactions to food due to pollen-allergen specific IgE cross-reacting with homologous food allergens. The tertiary structure of Pru av 1, the major cherry (Prunus avium) allergen, for example, is nearly identical with Bet v 1, the major birch (Betula verrucosa) pollen allergen. In order to define cross-reactive IgE epitopes, we generated and analysed mutants of Pru av 1 and Api g 1.0101, the major celery (Apium graveolens) allergen, by immunoblotting, EAST (enzyme allergosorbent test), CD and NMR spectroscopy. The mutation of Glu45 to Trp45 in the P-loop region, a known IgE epitope of Bet v 1, significantly reduced IgE binding to Pru av 1 in a subgroup of cherry-allergic patients. The backbone conformation of Pru av 1 wild-type is conserved in the three-dimensional structure of Pru av 1 Trp45, demonstrating that the side chain of Glu45 is involved in a cross-reactive IgE epitope. Accordingly, for a subgroup of celery-allergic patients, IgE binding to the homologous celery allergen Api g 1.0101 was enhanced by the mutation of Lys44 to Glu. The almost complete loss of IgE reactivity to the Pru av 1 Pro112 mutant is due to disruption of its tertiary structure. Neither the mutation Ala112 nor deletion of the C-terminal residues 155-159 influenced IgE binding to Pru av 1. In conclusion, the structure of the P-loop partially explains the cross-reactivity pattern, and modulation of IgE-binding by site-directed mutagenesis is a promising approach to develop hypo-allergenic variants for patient-tailored specific immunotherapy.
Allergens↗
Review of methods used to estimate non-milk extrinsic sugars.
BACKGROUND: Those sugars in foods, which are potentially damaging to dental health, were classified by the Committee on Medical Aspects of Food Policy (COMA) as non-milk extrinsic sugars (NMES). The NMES include sugars outside the cellular structure of a food, excluding the sugars naturally present in milk and milk products. The NMES should contribute no more than 10% of energy intake (Department of Health, 1991). A number of studies have been published where NMES content of foods has been estimated. The purpose of this study was to carry out a comprehensive literature review using a methodical search strategy in order to identify the different methods that have been used for NMES estimation. METHODS: Databases searched were MEDLINE, EMBASE, Health-CD and Health Management Information Consortium (HMIC) (as sources of UK government and other official publications). RESULTS: In total, 32 publications were found in which NMES values were reported and five different methods to estimate NMES were identified. No published method provided sufficient information to clearly differentiate between methods and inadequate detail was given to support replication of any of the methods. Of these five methods, The Ministry of Agriculture, Fisheries and Food (MAFF) have published three different descriptions of methods of NMES estimation used in UK national dietary surveys published since 1989. However, one method has been described consistently in the National Diet and Nutrition surveys published since 1994. CONCLUSIONS: A single, uniform approach to the estimation of NMES for application in nutritional surveys is essential for cross-comparison between surveys. The results show that there is a clear need for one standardized approach for the estimation of NMES in foods.
Animals↗
Street food vending in Latin America.
Despite occasional attempts to repress it, street food vending in Latin America appears to be on the rise--encouraged by growing marginal urban populations, the unemployed status of innumerable potential street vendors, lengthening commutes for workers, public demand for cheap and culturally appropriate food near workplaces, and a shortage or absence of regular establishments serving such food. Besides placing a hidden burden on public services, the generally unregulated and quasi-clandestine street food industry tends to observe poor hygienic practices and to pose significant public health problems. Within this context, Latin America's cholera epidemics have drawn increasing attention to street food's potential for disease transmission and have created growing support for attempts to resolve these troubles. What appears needed at this point, rather than futile attempts at abolition, is a new and more positive approach wherein countries change their regulations so as to permit peaceful and constructive adaptation of street food vending to a new style of Latin American social life. This implies legal reorganization directed at structurally developing street food vending and permitting application of measures--especially provision and use of safe water--that will foster good hygiene and safe foods. It also implies creating programs to provide appropriate training for inspectors as well as health education for both vendors and consumers of street food; and it implies promoting and adopting improved methods for preparing and selling such food. There is no reason to suppose these measures will provide an immediate panacea for the street food vending problem; but there is good reason to think they can immensely improve the situation that exists today.
Food Handling↗
Structural determination of subsidiary colors in commercial Food Green No. 3 (fast green FCF, FD & C Green No. 3).
HPLC analysis revealed that eight subsidiary colors existed in commercial Food Green No. 3 (fast green FCF, FD & C Green No. 3). Among them, four subsidiary colors C, F, G, and H were isolated by using preparative HPLC and their structures were determined by MS and NMR. They were the disodium salt of 2-[[4-[N-ethyl-N-(3- sulfophenylmethyl)amino]phenyl][4-[N-ethyl-N-(4- sulfophenylmethyl)amino]phenyl]methylio]-4-hydroxybenzenesulfonic acid (abbreviated as m,p-G-3), the sodium salt of 2-[[(4-N-ethylamino)phenyl][4-[N-ethyl-N-(3- sulfophenylmethyl)amino]-phenyl]methylio]-4-hydroxybenzenesulfonic acid [abbreviated as HSBA-(EA) (m-EBASA)], the sodium salt of 2-[[(4-N-diethylamino)phenyl][4-[N-ethyl-N-(3- sulfophenylmethyl)amino]phenyl]-methylio]-4-hydroxybenzenesulfonic acid [abbreviated as HSBA-(di-EA) (m-EBASA)], and the sodium salt of 2-[[4-[N-ethyl-N-(phenylmethyl)amino]phenyl][4-[N-ethyl-N-(3- sulfophenylmethyl)-amino]phenyl]methylio]-4-hydroxybenzenesulfonic acid [abbreviated as HSBA-(EBA)(m-EBASA)], respectively. HSBA-(di-EA) (m-EBASA) was a subsidiary color newly found in commercial Food Green No. 3.
Chromatography, High Pressure Liquid↗
Food choice by older people: the use of semi-structured interviews with open and closed questions.
OBJECTIVE: To evaluate difficulty chewing, consequent food choice and impacts using both open and closed questions within a semi-structured interview format. DESIGN: A cross-sectional study using a semi-structured interview (SSI) with open and closed questions. SETTING: Independently living people in South-West London interviewed in their own homes. SUBJECTS: A group of 54, edentate people (mean age 82, R = 60-93 years) were studied. RESULTS: Most subjects (69%) expressed difficulty eating at least one type of food, half were unwilling to eat the foods they found difficult, others were conscious of cooking longer or cutting smaller in order to manage these foods, although no one accepted that they overcooked food. There were dramatic differences in the number of subjects expressing difficulty to chew various foods when responding to open and closed questions. Roast beef proved a good discriminator in this group of predominantly English subjects. The importance of the questioning process was also shown by the discrepancy of responses between variously prepared apples and the inability of any subjects to bite an unpeeled apple. CONCLUSIONS: For sensitive appraisal of food choice it is obviously essential to assess relevant foods, for the culture of the group being studied. Open questions provide a way of exploring which are the appropriate foods and food preparation as criteria to assess perceived chewing ability and treatment benefit. The semi-structured interview method is particularly valuable for the study of older people. Closed questions provide different information which is also necessary to secure recall by older people.
Aged↗
Chemical modifications and genetic engineering of food proteins.
Relationships of structure to function of proteins can be studied using chemical modifications of amino-acid side chains and, more recently, recombinant deoxyribonucleic acid techniques to alter primary sequences. A wide array of chemical modifications are available to the food chemist for manipulating the functionality of food proteins. The esterification of side-chain carboxyl groups in proteins to yield polycationic polymers is emphasized in this review as an example of changing the functionality of a protein via chemical derivatization. However, chemical modifications of proteins generally suffer from a lack of control in the extent of derivatization attainable, oftentimes yielding polydisperse products. Recent advances in recombinant deoxyribonucleic acid technology offer the opportunity to relate systematically well-defined alterations in the primary sequence to changes in protein functionality. Using oligonucleotide-directed mutagenesis, one can now use synthetic oligodeoxynucleotides to prepare semisynthetic genes coding for specific changes in the primary sequence of proteins. Incorporation of the altered genes into an appropriate host can lead to the production of the modified protein for structure-function relationship studies. These recombinant deoxyribonucleic acid techniques may eventually provide the means to engineer proteins and enzymes.
Circular Dichroism↗