Changes in fatty acid composition in muscle of three farmed carp fish species (Labeo rohita,Cirrhinus mrigala,Catla catla) raised under the same conditions

This study was carried out to determine the proximate composition, fatty acid profile and biometric data for farm fish species Labeo rohita, Cirrhinus mrigala, Catla catla raised under identical conditions. The analysed fish species were found as source of high polyunsaturated fatty acids with low fat high protein. Fat content of the fish fillets was in range 2.57–3.11 g/100 g. Whereas fat content for feed was 14.90 g/100 g. The protein level for the three fish ranged from 20.00–23.57 g/100 g and in feed it was estimated in the range of 67.70 g/100 g. The palmitic acid and stearic acid were the main saturated fatty acids (SFA), oleic acid was the predominant MUFA while the docosahexanoic acid and eicopentanoic acid were the major PUFA. The percentage of DHA exceeded that of EPA in all fish species analysed. The n−3/n−6 ratio ranged from 1.69–1.91. PUFA/SFA ratio was much higher in L. rohita (1.40) due to abundance of n−3 PUFA, particularly DHA.     

The histology of grain caryopses for nutrient location: a comparative study of six cereals

In this study, we compare the histological localisation of phenols and β‐glucan in six cereal cross sections. The concentrations of β‐glucan and total phenols in whole grain flour (WGF) were also investigated to provide their nutrient content in grams. Cross sections of durum, soft, einkorn and emmer wheat, oats and barley were stained with Azan Trichrome (ATH) and periodic acid–Schiff (PAS) to characterise the morphology and cytohistology of the living cells in the aleurone, subaleurone and germ, as well as the a‐nucleated cells in the starchy endosperm. Phenol localisation in the outer layers was performed by fluorescence microscopy due to the presence of ferulic acid. β‐Glucan, examined with Calcofluor White staining, was found to be located primarily in the subaleurone layer and starchy endosperm of oats and barley. Our findings shed light on why WGF nutritional value is markedly reduced when the bran is removed through milling.     

Postmortem changes in bovine troponin T isoforms on two-dimensional electrophoretic gel analyzed using mass spectrometry and western blotting: The limited fragmentation into basic polypeptides

To comprehend postmortem changes in troponin T (TnT), whole beef proteins were developed on a two-dimensional electrophoretic gel. Multiple TnT-related spots were identified by both western blotting and MALDI-TOF MS utilizing bovine TnT isoform mRNA sequences. More than 10 TnT fast-type isoform spots (pI 5.7-9.6<) and the two slow-type isoform spots (pI 5.6-5.7) were observed at slaughter. All the isoforms were degraded exclusively into basic spots (pI 9.6<) at day 14 postmortem. Some TnT-related phosphorylated spots present at slaughter had disappeared by day 14, suggesting that the phosphorylated N-terminal region was cut off during beef aging. The intact isoforms and the fragments were identified by the MS with sequence coverage of 20.8-62.7%, and two of the fragments included the cutting site peptide of a conventional 30kDa or of a slow TnT-derived fragment. These results revealed that all of the TnT isoforms are cut exclusively in the glutamic acid-rich amino-terminal region during postmortem aging.     

The significance of cooling rate on water dynamics in porcine muscle from heterozygote carriers and non-carriers of the halothane gene-a low-field NMR relaxation study

The post mortem changes in the chemical/physical state distribution of water were followed in pig muscle (M. longissimus dorsi) from heterozygote (n=12) and non-carriers (n=12) of the halothane gene exposed to two different cooling profiles using continuous low-field NMR relaxation measurements. T₂ relaxation data were analyzed using distributed exponential fitting analysis. Independent of genotype post mortem changes were observed in the two water populations characterizing water within the myofibrillar space (T₂₁) and the extra-myofibrillar space (T₂₂), respectively, as a function of chilling regime. The effect was most pronounced in samples from heterozygote carriers of the halothane gene. The obtained results strongly suggest that improved water-holding capacity of muscles upon fast chilling can be ascribed to a reduced accumulation of extra-myofibrillar water in the meat post mortem, and it is hypothesized that differences in the accumulation of extra-myofibrillar water post mortem can be ascribed largely to the time at which disruption of cell membrane integrity takes place.     

The effect of salt and fibre direction on water dynamics,distribution and mobility in pork muscle: A low field NMR study

The effect of salt concentration and fibre orientation on water within the meat matrix was investigated by low-field nuclear magnetic resonance (LF-NMR), water-binding capacity (WBC), diffusion studies and histological analysis. Pork M. longissimus thoracis et lumborum samples were cured with 5.7, 15.3 or 26.3% w/w NaCl at a parallel or perpendicular fibre direction. NMR transverse (T₂) relaxation identified three water components (T_2b, T₂₁ and T₂₂) which all exhibited characteristics correlated to WBC. Results indicated that T_2b increases with increasing NaCl concentration. Increasing intra-myofibrillar water and decreasing extra-myofibrillar water resulted in the highest WBC. Water diffused more quickly into the extra-myofibrillar space in samples cured at a parallel fibre direction. This water remained loosely bound in samples cured with the saturated solution (26.3% w/w NaCl) leading to decreased WBC. This study provides further information on water binding within the meat matrix by applying the results of LF-NMR to traditional water-binding theories.     

Systemic concentrations of hormones during the development of follicular waves in mares and women: a comparative study

Changes in systemic concentrations of FSH, LH, oestradiol and progesterone during the ovulatory follicular wave were compared between 30 mares and 30 women. Based on a previous study, the emergence of the future ovulatory follicle was defined as occurring at 13.0 mm in mares and 6.0 mm in women, and deviation in diameter between the two largest follicles was expected to begin at 22.7 mm in mares and 10.3 mm in women. Mean FSH concentrations were high in mares during the luteal phase, resulting from statistically identified FSH surges occurring in individuals on different days and in different numbers (mean, 1.5 +/- 0.2 surges/mare); the internadir interval was 3.9 +/- 0.3 days. In contrast, mean FSH in women was low during the luteal phase and increased to a prolonged elevation during the follicular phase. The prolonged elevation was apparent in each individual (internadir interval, 15.2 +/- 0.4 days). Changes in LH or oestradiol concentrations encompassing deviation were not detected in mares, but both hormones increased slightly but significantly between emergence and deviation in women. The hypothesis that a greater number of growing follicles causes a greater predeviation decrease in FSH was supported for mares (r, -0.39; P< 0.04), but a similar negative correlation (r, -0.36) was not significant in women. The hypothesis that the increase in oestradiol during the luteal phase in women was at least partly attributable to luteal-phase anovulatory follicular waves was not supported. Normalization of FSH concentrations to the day of emergence showed maximum value on the day of emergence with a significant increase and decrease on each side of emergence in both species. The day of expected deviation occurred 3 days after emergence during the decline in FSH in both species. These results indicated that the previously reported striking similarities in emergence and deviation between mares and women during the ovulatory follicular wave are associated with species similarities in the temporal relationships between follicle events and FSH concentration changes. Thus, mares may be useful research models for studying the role and mechanism of the action of FSH in emergence and deviation during the ovulatory follicular wave in women.     

Water retention properties and solubility of the myofibrillar proteins: Interrelationships and possible value as indicators of the gel strength in cod surimi by a multivariate data analysis

The quality of surimi made from fish aged on ice for up to 14 days was evaluated by compression test on a model product. Water holding capacity (WHC) and pH in the fish mince, and protein content, pH, salt solubility of the myofibrillar proteins and hydration index of the insoluble proteins (HUP) in the surimi, were determined. Their interrelationships and utility as indicators of surimi quality were evaluated by a multivariate data analysis. The main tendencies of variation among the chemical parameters were examined by the use of principal component analysis. Correlations between the chemical parameters (X-variables) and the gel strength of surimis (Y-variable) were studied by the use of partial least squares regression. Age of the raw material and protein content of the surimi seemed to be the main determinants of the gel strength. Among the remaining variables only HIIP showed a potential value as indicator of the gel strength. WHC and HIIP seemed to reflect two different water retention properties of the proteins.     

Putative virulence properties of Aeromonas strains isolated from food, environmental and clinical sources in Italy: a comparative study

The distribution of virulence properties in 142 strains of Aeromonas isolated from diarrhoeic patients, food and surface water in Italy and identified by biochemical and molecular methods was investigated. The virulence properties studied were the presence of genes for the aerolysin (aerA), heat-stable cytotonic enterotoxin (ast), heat-labile cytotonic enterotoxin (alt), cytotoxic enterotoxin (act); and cytotoxicity for Vero cells and adhesion on Hep-2 cells. A. hydrophila and A. caviae were the species most commonly isolated from clinical and environmental samples (9/30; 30.0% and 5/27; 18.5%, respectively) while mesophilic A. salmonicida was most common in food samples (19/80; 23.7%). Out of 142 strains, 86 (60.6%) were positive for at least one of the virulence properties. All the toxin genes were present in 4/18 (22.3%) of clinical strains. Most of the food isolates (54/55; 98.2%) were cytotoxic and most of the environmental strains (12/13; 92.3%) were adhesive. The aerA gene was present in most toxigenic strains (72/86; 83.7%), irrespective of their origin. The growth temperature affected the expression of cytotoxicity and adhesivity. Aeromonas strains from food and surface water frequently had toxin gene patterns similar to those of clinical strains and expressed virulence properties at human body temperature. These findings indicate that aeromonads have the potential to cause human illness and confirm the role of food and water as vehicles for Aeromonas diseases.     

Structural modification of spindle pole bodies during meiosis II is essential for the normal formation of ascospores in Schizosaccharomyces pombe: Ultrastructural analysis of spo mutants

In order to characterize the morphological steps defined by sporulation (spo) genes during the formation of ascospores in the fission yeast Schizosaccharomyces pombe, we performed an electron microscopic study of the ultrastructure of the spindle pole body (SPB) and of the development of the forespore membrane during the second meiotic division (meiosis II) in sporulation-deficient (spo) mutants (spo4, spo5, spo14 and spo18). No difference was found in terms of the function and the structure of the SPB during the first meiotic division (meiosis I) between the four mutants and wild-type cells. However, during meiosis II, the spo4 and spo18 mutants underwent nuclear division but in neither case were the SPBs modified nor were forespore membranes formed. The SPBs of the spo18 mutant diminished in size after meiosis II and eventually disappeared after 18 h in sporulation medium. By contrast, the SPBs of the spo4 mutant remained unchanged even after an 18-h incubation. The outer plaques of SPBs of spo5 and spo14 mutants were sufficiently modified to allow them to initiate development of the forespore membrane, but the membrane had an abnormally expanded lumen and did not enclose the nuclei during meiosis II. The spo5 mutant produced anucleate spore-like bodies while the spo14 mutant formed unorganized structures with irregular peripheries which, presumably, contained spore-wall precursors, instead of anucleate spore-like bodies. We conclude that the modification of the SPB is essential for the formation of ascospores and at least two genes (spo5 and spo14) participate in the development of the forespore membrane. The defective phenotypes define discrete steps in the development of ascospores, which proceeds via steps defined by the mutant spo4, spo18, spo14 and spo5 genes respectively. Our observations provide further substantial evidence that the SPB plays a pivotal role in the normal development of ascospores in yeasts.     

Formation and reduction of acrylamide in Maillard reaction: a review based on the current state of knowledge

The recent report of elevated acrylamide levels in heat processing foods evoked an international health alarm. Acrylamide, an acknowledged potential genetic and reproductive toxin with mutagenic and carcinogenic properties in experimental mammalians, has been found in various heat processing foods. Many original contributions reported their findings on the formation mechanism and possible reduction methods of acrylamide. The aim of this review article is to summarize the state-of-the-art about the formation and reduction of acrylamide in the Maillard reaction. This research progress includes mechanistic studies on the correlation between the Maillard reaction and acrylamide, the formation mechanism of acrylamide, the main pathways of formation and impact factors on formation including cultivars, storage temperature, storage time, heat temperature, heat time, environmental pH, concentration of precursors, effects of food matrixes, type of oil, etc. Meanwhile, primary mechanisms on the reduction of acrylamide as well as reduction pathways including material and processing related ways and use of exogenous chemical additives are systematically reviewed. The mitigation studies on acrylamide are also summarized by the Confederation of the Food and Drink Industries of the EU (CIAA) "Toolbox" approach.     

Potato: a comparative study of the effect of cultivars and cultivation conditions and genetic modification on the physico-chemical properties of potato tubers in conjunction with multivariate analysis towards authenticity

Potato (Solanum tuberosum L.) is a highly nutritious, mild flavored, easy to blend food that has many possibilities for "building in" desired nutrients. Varietal and environmental differences are known to exist in the shape, size, and nutritional content of potatoes. Different populations opt for varying sensory properties in relation to their diets. Potatoes are a low energy food in comparison to cereals and legumes. The aim of this review was to present an update of the currently conducted studies both on the characterization of several potato varieties (physical, chemical, and sensory analysis) and by means of genetic modification. Towards this target, five comprehensive tables were compiled where all recent data (physicochemical properties) and GM varieties were presented in conjunction with multivariate analysis (chemometrics). The latter was shown to be effectively used towards authenticity purposes (identification of geographical origin, variety, GM).     

Furan formation from vitamin C in a starch-based model system: Influence of the reaction conditions

The generation of furan from vitamin C during thermal treatment of a starch-based model system, which simulated baby food, was studied. Results indicated that the amount of sample heated in the vial influenced the furan generation from ascorbic acid. Increasing the amount of heated sample from 5% to approximately 98% of the total vial volume, drastically reduced furan formation from 70 ppb to 16 ppb. Changes in ascorbic acid concentrations from 0.1 to 4.5 mg/g did not influence furan concentration nor did different ascorbic/dehydroascorbic acid molar ratios. Interestingly, waxy corn starch itself considerably enhanced furan generation from ascorbic acid. Under the same conditions, 13.2 ppb of furan was generated in starch-based samples, while in ascorbic acid buffered solutions only 0.4 ppb of furan was formed. Application of other matrices, in particular agar and hydrolysed starch, resulted in similar furan concentrations as for native starch, while in polyol solutions furan concentrations were comparable to those obtained for the buffered ascorbic acid solutions.     

A comparative study on the transport of L(-)malic acid and other short-chain carboxylic acids in the yeast Candida utilis: Evidence for a general organic acid permease

Cells of the yeast Candida utilis grown in medium with short-chain mono-, di- or tricarboxylic acids transported L(-)malic acid by two transport systems at pH 3·0. Results indicate that probably a proton symport for the ionized form of the acid and a facilitated diffusion for the undissociated form were present. Dicarboxylic acids such as succinic, fumaric, oxaloacetic and α-ketoglutaric acids were competitive inhibitors of the malic acid for the high-affinity system, suggesting that these acids used the same transport system. In turn, competitive inhibition uptake studies of labelled carboxylic acid in the low-affinity range indicated that this system was non-specific and able to accept not only carboxylic (mono-, di- or tri-) acids but also some amino acids. Additionally, under the same growth conditions, C. utilis produced two mediated transport systems for lactic acid: a proton symport for the anionic form which appeared to be a common monocarboxylate carrier and a facilitated diffusion system for the undissociated acid displaying a substrate specificity similar to that observed for the low-affinity dicarboxylic acid transport. The mediated carboxylic acid transport systems were inducible and subjected to repression by glucose. In glucose-grown cells the undissociated dicarboxylic acids entered the cells slowly by simple diffusion. Repressed glucose-grown cells were only able to produce both transport systems if an inducer, at low concentration (0·5%, w/v), was present during starvation in buffer. This process was inhibited by the presence of cycloheximide indicating that induction requires de novo protein synthesis. If a higher acid concentration was used, only the low-affinity transport system was detectable, showing that the high-affinity system was also repressed by high concentrations of the inducer.     

The effect of sugars on the diffusion of water in starch gels: a pulsed field gradient NMR study

The self-diffusion coefficient of water was measured in starch–sugar–water systems of various compositions. The starch was either waxy maize or potato starch and the sugar was either sucrose or xylose. The diffusion results obtained from sugar solutions (i.e. with a zero polymer concentration) suggested that a free water behaviour should only be expected after a bilayer coverage of the sugar molecule. The presence of sugars was found to decrease considerably the translational mobility of water in starch gels. This reduction was proportional to the sugar concentration in the system but showed little dependence on the type of sugar. An attempt was made to relate the self-diffusion coefficients of water in starch–sugar–water gels to those obtained for the individual binary systems (starch–water and sugar–water). A prediction based on the additive effects of sugar and starch only corresponded with experimental results in dilute systems.     

Determination of the mycotoxin fumonisin B1 in maize by reversed-phase thin-layer chromatography: a collaborative study

A simple and cost-effective method using thin-layer chromatography for the determination of the mycotoxin fumonisin B₁ in maize is described. The analytical method consisted of the extraction of ground maize by shaking with methanol/water (75:25) for 60 min and clean-up of the resultant extract by means of strong anion exchange solid-phase extraction. The purified residue, formed by evaporation of the elution solvent, was reacted with fluorescamine and the fumonisin B₁-derivative was separated by reversed-phase thin-layer chromatography using a developing solution of methanol/aqueous 4% potassium chloride (70:30). The derivatized FB₁ was readily visualized as a greenish-yellow spot under long wavelength ultraviolet light and quantified by visual comparison with a set of similarly derivatized standards in the range 20-300 ng FB₁ spotted on plate. Based on visual comparison, levels down to 0.5 mg kg^-1 were successfully estimated. The method was collaboratively studied in 14 laboratories using four duplicate maize meal samples (including a blank) and a spiked sample for determination of recovery. No significant difference was observed between mean FB₁ levels by high-performance liquid chromatography or thin-layer chromatography. Based on within-laboratory relative standard deviations of 27.1-41.7% and between-laboratory relative standard deviations of 35.0-63.3%, the method can be considered semiquantitative. The mean recovery achieved by participants at a spiking level of 2.00 mg kg^-1 was 74.5%.     

民国丝绸印花品种及工艺技术发展概述 ——以传世旗袍织物为中心的研究

民国是中国近代丝绸印花的发端时期,也是走向商业化、大众化、国际化的繁荣时代.文章从笔者收藏、拍摄的民国传世旗袍中,选择具有代表性的部分织物,对民国丝绸印染的品种分类、设计方法、技术发展等进行了考察、界定、研究.并对民国丝绸印染品种发展中的创新成果、借鉴途径,以及存在的不足进行了全面、系统的梳理,研究表明:民国丝绸印花创...     

无溶剂体系脂肪酶催化大豆油水解反应动力学——界面面积与反应初速度

对无溶剂体系中C.lipolytica脂肪酶催化大豆油水解反应过程中的油水界面面积与反应初速度进行了研究.对超声波反应器和振荡水浴两种不同的方式进行了比较,超声波较振荡水浴具有更好的分散作用,油滴粒径更小,界面面积更大;提高振荡速度和超声波强度,均可以增大界面面积;振荡水浴中,界面面积随油相体积分数的增加而减少;超声波反应器中,界面面积随油相体积分数的增加先增加后减少;反应初速度与界面面积呈线性相关,反应初速度随界面面积的增加而增大,当油相体积分数为0.7,超声波强度为1.64 W/cm~2时,反应初速度最大,为161 mol/(m~3·min).     

Dietary exposure to trace elements and health risk assessment in the region of Valencia,Spain: a total diet study

ABSTRACT

Dietary exposure of the Valencian region population to lead, cadmium, inorganic arsenic (iAs), chromium, copper, tin and methylmercury (meHg) was assessed in a total diet study carried out in the region of Valencia in 2010–11. A total of 8100 food samples were collected and analysed. Occurrence data were combined with consumption data to estimate dietary exposure in adults (> 15 years of age) and young children (6–15 years of age). The estimated intake was calculated by a probabilistic approach. Average intake levels (optimistic scenario) for lead, iAs, chromium and tin were 0.21, 0.08, 1.79 and 1.87 µg kg^?1 bw day^?1 respectively; for Cd and meHg average intake levels were 0.77 and 0.54 µg kg^–1 bw week^?1, respectively, and for Cu, 1.60 mg day^?1. In terms of risk characterisation, the results showed that 2.84% of the adult population may exceed the BMDL₁₀ (benchmark dose lower confidence limit) established for Pb, which is linked to renal effects; whereas 28.01% of the young children population may exceed the BMDL₀₁ related to neurodevelopment effects. In addition, 8.47% of the adult population and 12.32% of young children exceeded the meHg tolerable weekly intake (TWI).     

Enhanced accumulation of toxic compound in yeast cells having high glycolytic activity: a case study on the safety of genetically engineered yeast

The cellular level of methylglyoxal (MG), a highly toxic 2-oxoaldehyde, in Saccharomyces cerevisiae cells transformed with genes for some of the glycolytic enzymes was determined as an index of the safety of genetically engineered yeast and the level was compared with that in non-transformed control cells. the phosphoglucose isomerase (PGI), phosphofructokinase (PFK) and triosephosphate isomerase (TPI) activities significantly increased in the transformants and were approximately five-, three- and sevenfold higher, respectively, than those in the control. When these transformed cells were used for alcohol fermentation from glucose, they accumulated MG in cells at a level sufficient to induce mutagenicity. These results illustrate that careful thought should be given to the potential metabolic products and their safety when a genetically engineered yeast is applied to food-related fermentation processes.