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Antioxidant system loss after slaughtering, reactive species production, cell disruption, contact with oxygen and light, heme and nonheme iron, and irradiation starts up mainly by 2 related oxidative processes: lipid peroxidation and protein oxidation. Products generated in these processes are responsible for meat quality loss, and some of them are suspected to be toxic to humans. This review article is focused on reactive species implicated in oxidative processes in meat, on lipid peroxidation mechanisms, heme protein, and nonheme protein oxidation, and on some toxic oxidation and digestion products. Nonenzymatic fatty acid peroxidation is exemplified by an arachidonic acyl group, and the initiation of chain reaction can be described by 3 pathways: singlet oxygen, hydroxyl radical from the Fenton reaction, and perferrylmyoglobin. Enzymatic oxidation of fatty acids is exemplified using linoleic acid, and the main characteristics of lipoxygenase are also presented. Heme protein oxidation is described in an interrelation with lipid peroxidation and the significance for food quality is shown. For protein oxidation, 3 different mechanism types are described: oxidation of amino acid residues, oxidation of protein backbone, and reactions of proteins with carbonyl compounds from lipid peroxidation. The effects of oxidative damage on protein properties and bioavailability are also shown. At the end of each oxidative process, the postprandial toxicity induced by oxidation products and the dietary degradation products are presented. Also discussed are reports by some researchers who suggest that dietary lipid and protein oxidation products and heme iron from red meat are in part cytotoxic and/or genotoxic. [ABSTRACT FROM AUTHOR]

The soybean [ Glycine max (L.) Merr.] is grown worldwide for its high protein and oil contents. Characterization of soybean seed components lends itself to understanding how soybean production can meet the needs of a growing world population. For this article, literature was reviewed and condensed to create a well-rounded picture of the current understanding of structural, functional, and nutritional properties of soybean components. Natural variation in soybean protein, lipid, and carbohydrate components, as well as the minor constituents phytic acid and isoflavones, are mentioned. Environment- or genetic-induced shifts in natural variation are described with respect to nutrition and functional improvements in soybean. [ABSTRACT FROM AUTHOR]

Partition coefficients that are used to predict concentrations of hydrophobic organic chemicals in biota (e.g., the bioconcentration factor) often assume that the sorptive capacity of an organism or tissue is adequately represented by its lipid content. In lean organisms and tissues, however, theory suggests that partitioning may be strongly influenced by the sorptive capacity of nonlipid materials, such as protein. Little is known about the sorptive capacity of proteins for hydrophobic organic chemicals, and methods to include proteins in bioaccumulation models do not exist. Here, we present a compilation and meta-analysis of published data to estimate the relative sorptive capacities of animal proteins and lipids for neutral organic chemicals. We found that the estimated sorptive capacity of protein in solid animal tissues ranged from around 1 to 10% that of lipid for compounds with a log octanol/water partition coefficient (KOW) of greater than two. The sorptive capacity of blood protein (albumin) appeared to be substantially higher than this, especially for low-KOW chemicals. For modeling purposes, we recommend estimating the sorptive capacity of animal protein as 5% that of lipid. According to this estimate, the sorptive capacity of an animal or tissue will be dominated by the contribution from protein if the lipid content makes up less than 5% of the dry-weight organic content. In such situations, a consideration of the sorptive capacity of nonlipid constituents, such as protein, will permit more accurate predictions of chemical accumulation and distribution. [ABSTRACT FROM AUTHOR]

Extrusion cooking, as a multi-step, multi-functional and thermal/mechanical process, has permitted a large number of food applications. Effects of extrusion cooking on nutritional quality are ambiguous. Beneficial effects include destruction of antinutritional factors, gelatinisation of starch, increased soluble dietary fibre and reduction of lipid oxidation. On the other hand, Maillard reactions between protein and sugars reduce the nutritional value of the protein, depending on the raw material types, their composition and process conditions. Heat-labile vitamins may be lost to varying extents. Changes in proteins and amino acid profile, carbohydrates, dietary fibre, vitamins, mineral content and some non-nutrient healthful components of food may be either beneficial or deleterious. The present paper reviews the mechanisms underlying these changes, as well as the influence of process variables and feed characteristics. Mild extrusion conditions (high moisture content, low residence time, low temperature) improve the nutritional quality, while high extrusion temperatures (⩾200 °C), low moisture contents (<15%) and/or improper formulation (e.g. presence of high-reactive sugars) can impair nutritional quality adversely. To obtain a nutritionally balanced extruded product, careful control of process parameters is essential. [ABSTRACT FROM AUTHOR]

The chemical composition of organisms in relation to their environmental resource availability is an area of intense research activity. We studied the changes in cell composition of the cyanobacterium Phormidium autumnale in response to prolonged darkness. Cells allocated their internal resources in a homeostatic manner, oxidizing all the three major cellular constituents in a proportional way. This resulted in constant C/N and carbohydrates, lipids and proteins ratios that remained unaltered throughout the whole incubation period. We propose the maintenance of balanced cell composition (homeostasis) as an evolutionary strategy related to environmental transitory changes. [ABSTRACT FROM AUTHOR]

The growth characteristics, biochemical composition and ultrastructure of a novel starchless mutant of Chlorella pyrenoidosa, designated as STL-PI, are compared to the same characteristics of its parental strain, C. pyrenoidosa 82T. The STL-PI mutant had a 22 ± 5% higher growth rate, and 24.5 ± 4.2% more protein than the parental strain, 82T. Furthermore, the STL-PI mutant accumulated 20.4% more polyunsaturated fatty acids and 18% less saturated fatty acids than the parental 82T. When the parental 82T was cultured in a nitrogen-free media, their starch content increased from 6.8 ± 2.8% to 22.5 ± 3.1%. In contrast, the STL-PI mutant produced no starch, regardless of the growth conditions. Instead, the mutant cells responded to nitrogen limitation by further increasing their lipid content from 25.2 ± 1.2% to 38.0 ± 2.3% per dry weight. Transmission electron micrography revealed that nitrogen limitation typically stimulates the formation of starch granules in the chloroplast of 82T cells. Yet no starch granules were observed in the STL-PI cells. Instead, only the formation of large lipid globules was observed in the mutant cells. These results demonstrate that the starchless mutant STL-P1 possesses novel physiological and phytochemical properties distinct from the 82T cells: their cells were deficient in starch synthesis and showed higher growth rates and productivity than 82T cells. [ABSTRACT FROM AUTHOR]

We collected 341 northern pintails (Anas acuta) along the lower Texas coast, USA, to investigate dynamics of carcass and digestive tract components during winter to help assess the ability of this region to support wintering pintail populations. Pintails relied more on endogenous lipid and protein reserves during winter of a dry year than a normal to wet year. Carcass fat remained relatively stable during the wet winter; however, pintails catabolized approximately 65% of their lipid reserves between arrival in October and departure at the end of February during the dry winter. Somatic protein mass also declined over both winters as pintails catabolized up to 20% of their muscle mass. Gizzard atrophy explained most of the changes in somatic protein during the wet winter, whereas catabolism of breast muscle also contributed to changes in protein mass during the dry winter. Ingesta-free digestive tract mass was greatest in early December, and then declined abruptly through February during both winters. Pintails departed the lower Texas coast in late February approximately 20% lighter in body mass than when they arrived in autumn. Mid-continent pintails may frequently opt to winter in southerly latitudes where they can maintain minimal endogenous reserves due to the moderate climate, limited human disturbance, and relatively dependable, but often lower-quality food resources. However, potential consequences of pintails initiating spring migration with reduced energy reserves include greater reliance on spring staging and breeding areas to meet their nutrient requirements for migration and reproduction, later arrival on breeding grounds, and reduced survival and reproductive success. Nutrient reserve dynamics of wintering, mid-continent pintails support the need for enhanced conservation of productive spring staging and breeding habitats for this population. It also provides additional concern over the loss of productive wintering sites along the western Guff Coast. [ABSTRACT FROM AUTHOR]

The content (% wet mass) in water, ash, lipid, crude protein, DNA and RNA of different tissues was determined during sexual maturation of bonitos Sarda sarda from the Aegean Sea. A total of 220 specimens were collected in the following stages of sexual maturity: immature, resting, developing, mature, spawning and spent. Highest lipid levels in the white muscle, red muscle and liver were measured in immature specimens, while lowest levels were found in spawning bonitos. The gradual percentage of lipid reduction from immature to spawning bonitos was relatively higher in the liver (females 71·2% and males 64·4%) than in the white (females 59·2% and males 53·5%) and red (females 62·1% and males 51·7%) muscle. Lipid levels in the gonads increased gradually from the immature to spawning stage. The decrease of lipid in the somatic tissues was more intense in females than in males, and gonadal lipid content was higher in females than in males. There was a strong reverse correlation between water and lipid percentage in all tissues. Protein content decreased significantly only in spawning bonitos. The percentage of protein reduction from immature to spawning stage was relatively higher in males than in females in both white (females 3·4% and males 4·6%) and red (females 4·6% and males 5·1%) muscles. Protein content in the liver was significantly lower than in the other tissues, being highest in mature females. Gonadal protein content in females increased with maturation and decreased after spawning. The content in ash exhibited considerable stability. The RNA:DNA ratio exhibited a similar pattern of variation in both muscles. The RNA:DNA ratio increased during gonadal development gradually from the developing to spent stage. It was concluded that in S. sarda during gonadal development, there was an increase in gonadal lipid accompanied by a decrease in somatic tissue lipid reserves. Thus, reproductive inactive bonitos have more lipid in their edible part and a higher nutritional value than active ones. [ABSTRACT FROM AUTHOR]

Disposal of organic waste materials from the meat- and vegetable-processing industries historically has been undertaken by dumping, drying followed by combustion, or biological oxidation. As a result of higher intensity processing rates and increasingly stringent legislation, these are no longer economical. Hydrothermal oxidation, also referred to as "wet" oxidation, has been used to lower the chemical and biological oxygen demand of waste samples from the above two industries. The starch-based wastes were readily oxidized without a catalyst. For the lipid and protein-based wastes, the use of copper calcium silicate and nitrate catalysts provided a significant reduction in oxygen demand at 230°C. [ABSTRACT FROM AUTHOR]

Background/purpose: The aging process has been studied with fervor recently, given our shifting demographics. As age's effects are so manifest in the skin's appearance, structure, mechanics, and barrier function, it is not surprising that much effort has been made in research to better understand them. Quantitative measurements permitted by bioengineering have allowed us to objectively and precisely study aging skin. These overviews piece together the immense amounts of information that have emerged from recent technological advances in dermatological research in order to develop a unified understanding of the quantitative effects of age on skin. Methods: We performed a literature search on age-related changes in protein, glycosaminoglycan (GAG), water, and lipid content and structure, searching Pub-med, Em-Base, Science Citation Index, and the UCSF dermatological library's collection of books on the topic of aging skin. Results: Collagen becomes sparser and less soluble in intrinsically aged skin, but is thickened and more soluble in extrinsically aged areas. Elastin is degraded slowly and accumulates damage with intrinsic aging; also, increased synthesis of abnormally structured elastin occurs in photoexposed areas. This leads to an age-related accumulation of aberrant elastoic material, clumped in the papillary dermis. Generally, age leads to increased folding and decreased interaction of proteins with water. Also, despite increased GAGs in aged skin, these are abnormally deposited on the elastoic material and cannot interact properly with water. Hence, in aged skin, water is found in the tetrahedron form, bound to itself rather than other molecules. Lipid content appears to decrease with age, although the proportion of different lipid classes seems to remain fairly constant. Conclusion: Much work remains to be carried out to reach a consensus on the effects of age on skin structure and function. Future studies would be benefited by increased standardization of skin sites tested, methodology, and increased sample sizes. [ABSTRACT FROM AUTHOR]

The nutritional status of Atlantic salmon Salmo salar parr was assessed by examining how proximate body composition and energy content (kJ g&sup-1;) were associated with the habitat rearing origin of parr utilizing fluvial or lacustrine areas. Comparisons were made among sampling sites within the two habitats, as well as between the two major habitat types applying both fixed effect and random effect models. Mean protein concentration varied from 13.87 to 15.67% among fluvial sites, and from 14.96 to 16.38% among lacustrine sampling locations. Mean fat concentration ranged from 1.71 to 3.32% and from 2.22 to 4.29% among fluvial and lacustrine locations, respectively, with energy concentration, on average, c. 11% higher in lacustrine parr. Interpretation of results of comparisons between habitats was dependent upon the statistical model used. Benefits associated with lacustrine rearing, such as greater body size and nutritional status, have implications for overwintering survival in fresh water as well as subsequent survival during initial sea entrance as smolts. [ABSTRACT FROM AUTHOR]

From 5% w/v whey protein isolate (WPI), whey protein/lipid emulsion edible films were produced that were sorbitol- or glycerol-plasticized, containing butterfat (0.2% w/v) or candelilla wax (0.8% w/v). Thermal properties of the films determined by Differential Scanning Calorimetry (DSC) showed onset temperatures (To) of 126 to 127 °C for sorbitol- and 108 to 122 °C for glycerol-plasticized films. To values were used as the basis for heat sealing temperatures. Temperature (110, 120, 130 °C], pressure (296, 445 kPa), and dwell time (1, 3 s) affected seal strength. Optimum heat sealing temperature was 130 °C for sorbitol- and 110 °C for glycerol-plasticized films. All films were heat sealable with an impulse heat-sealer. Electron Spectroscopy for Chemical Analysis (ESCA) of the surfaces of both sealed and unsealed films showed increase in hydrogen and covalent bonds involving C-O-H and N-C, which may be the main forces responsible for the sealed joint formation of the films. [ABSTRACT FROM AUTHOR]

Vietnamese edible marine macro-algae (seaweed) are of interest because of their value in nutrition and medicine. Vietnamese living in the coastal have traditionally utilized seaweeds species as food supplement and herbal medicine. They consumed seaweed as food in various forms: raw as salad and vegetable, pickle with sauce or with vinegar, relish or sweetened jellies and also cooked for vegetable soup. As herbal medicine, seaweed is usually used for traditional comestics, treatments for cough, asthma, hemorrhoid, boils, goitres, stomach ailments, urinary diseases, reduce the incidence of tumors, ulcers and headaches. Although Vietnam has an abundance of algae floral with total number of species is estimated to be nearly 1000 spp. in which there are 638 species of marine algae identified. However, there have been no intense study regarding to changes in marine algal chemistry. The fifteen species of edible seaweeds studied in this paper include green, brown and red algae. The proximate compositions as ash, protein, lipid, carbohydrate, fatty acids, vitamines, pigments, macro and micro-elements were compared among different species examined and the genetic relationships among them by analyzing the species-specific differences in nucleotide sequences of ITS-1 region of the ribosomal DNA was identified. [ABSTRACT FROM AUTHOR]

Amaranth protein–lipid (PL) and protein (P) films were elaborated and compared with amaranth flour films in order to determine the contribution of the interactions between the biopolymer (starch and protein) and the lipids to the film properties. The films were made by the casting method, using the same glycerol concentration (0.9 g glycerol/100 g solution). A separation of the lipid fraction in the PL films and a polymorphic transformation of the corresponding fatty acids were observed by differential scanning calorimetry (DSC) and verified by an analysis of the microstructure by scanning electron microscopy (SEM). The flour films showed no separation of the lipid fraction, evidence that the lipids were strongly associated with the proteins and homogenously distributed throughout the starch network, contributing to the good mechanical properties when compared to the PL films and to the excellent barrier properties when compared to both the PL and P films. The protein-protein interactions also contributed to the mechanical properties of the flour films. The presence of proteins and lipids in the flour films had an important effect on film solubility, and also on the color and opacity of the films. This study showed that the flour film properties depended on the interactions formed by their polymers (starches and proteins) and by the lipid, on the distribution of these interactions within the film matrix and on the concentrations of each component in the film. [ABSTRACT FROM AUTHOR]