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1.
Poult Sci ; 102(7): 102680, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37120871

RESUMO

This study aimed to determine the skin protective effect of egg yolk phosvitin phosphopeptides (PPPs). Phosvitin was separated from the egg yolk, and PPPs were produced using high-temperature and mild-pressure (HTMP) pretreatment and enzyme-sterilization hydrolysis combinations. The elastase and melanogenesis inhibitory activities and anti-inflammatory effects of egg yolk PPPs were determined. All PPPs significantly inhibited elastase activity, but the PPPs prepared with HTMP pretreatment and trypsin-sterilization (HTMP-T-S) combination suppressed the tyrosinase activity the most. PPPs (3 mg/mL) inhibited the α-melanocyte-stimulating hormone-induced melanin production in B16F10 melanoma cells by 31.18 to 38.58%. In addition, PPPs effectively inhibited nitric oxide (NO) production in the LPS (lipopolysaccharide)-stimulated RAW 264.7 macrophages, and the PPPs from HTMP-T-S exhibited the highest inhibitory activity. The protein expressions of pro-inflammatory enzymes, inducible nitric oxide synthase, and cyclooxygenase-2 were down-regulated by the PPPs from the HTMP-T-S. Therefore, PPPs could be used as an anti-melanogenic, anti-elastase, and anti-inflammatory agent for humans and skin care products.


Assuntos
Fosfopeptídeos , Fosvitina , Humanos , Animais , Elastase Pancreática , Temperatura , Hidrólise , Galinhas , Anti-Inflamatórios/farmacologia , Melaninas
2.
Pathogens ; 12(2)2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36839458

RESUMO

Outbreaks of human gastroenteritis have been linked to the consumption of contaminated domestic and imported seafood. This study investigated the microbiological quality of seafood obtained from retail stores on the Eastern Shore of Maryland. A total of 440 samples of domestic and imported frozen shrimp, catfish and tilapia samples were analyzed for aerobic plate count (APC), total coliforms, Escherichia coli and seafood-borne-pathogens (Vibrio parahaemolyticus, Vibrio vulnificus, Salmonella, Campylobacter jejuni). The prevalence of APC, coliforms and E. coli positive samples was 100%, 43% and 9.3%, respectively. Approximately 3.2%, 1.4%, 28.9% and 3.6% of the samples were positive for V. parahaemolyticus, V. vulnificus, Salmonella and Campylobacter jejuni, respectively. The MPN/g ranges were 150-1100 MPN/g for vibrios, 10-1100 MPN/g for Salmonella and 93-460 MPN/g for C. jejuni in seafood, respectively. Comparing bacterial prevalence by type or source of seafood, the only significant difference identified was Salmonella-positive imported tilapia (33.3%) versus domestic tilapia (19.4%). The quantitative data on pathogen levels in the present study provide additional information for quantitative risk assessment not available in previous surveys. The findings of this study suggest the association of potential food safety hazards with domestic and imported seafood and warrant further large-scale studies and risk assessment.

3.
Animals (Basel) ; 11(10)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34679860

RESUMO

This study was designed to evaluate the effects of dietary supplemental DL-methionine (MET) on live performance and meat yield for broilers raised to a common weight. A total of 1552 one-day old Ross 708, sexed broilers were randomly distributed to 32 pens resulting in eight treatments (TRT) of four replicates with 44 male or 53 female/pen. A randomized complete block with a 2 × 4 (sex × 4 MET levels 0, 0.5, 1, and 2 g/kg) factorial arrangement of TRT was used. A common weight of 2400 g was approached by day 46 (1 and 2 g MET/kg feed) and day 48 (0 and 0.5 g MET/kg feed). Supplementation of MET at 1, and 2 g/kg had a lower (p < 0.01) feed conversion ratio (FCR) at day 46/48 than broilers fed 0.5 g MET/kg. Broilers without supplemental MET had the worst (p < 0.01) feed conversion and average daily gain (ADG) at day 46/48. Birds fed 0 g MET/kg of feed had lower (p < 0.05) whole eviscerated carcass without giblets (WOG), yield than birds fed 2 g MET/kg of feed. Additionally, birds fed 0 g MET/kg of feed had lower (p < 0.05) breast fillet and tender percent yields than birds fed supplemental MET. Elimination of MET from organic broiler diets resulted in reduced ADG, breast fillet yield and feed efficiency of meat yield of broilers raised to day 46/48. Reduction in MET supplementation below current levels reduced the efficiency of meat production of organic broilers raised to day 46/48.

4.
J Agric Food Chem ; 67(51): 14086-14101, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31766846

RESUMO

The effect of high-temperature and mild-pressure (HTMP) pretreatment on the enzymatic hydrolysis of phosvitin and the structural characteristics of the phosphopeptides produced were analyzed using tandem mass spectrometry. The HTMP pretreatment hydrolyzed phosvitin at random sites and helped the subsequent enzyme hydrolysis of the peptides produced. With the HTMP pretreatment alone, 154 peptides were produced, while the use of trypsin, Protex 6L, and Multifect 14L in combination with the pretreatment produced 252, 280, and 164 peptides, respectively. The use of two enzyme combinations (trypsin + Protex 6L and trypsin + Multifect 14L) helped the hydrolysis further. The number of phosphopeptides produced increased when the modifications within the same amino acid sequences were considered. This study indicated that HTMP pretreatment was a breakthrough method to improve the enzymatic hydrolysis of phosvitin that enabled an easy production of phosvitin phosphopeptides for their subsequent functional characterizations.


Assuntos
Métodos Analíticos de Preparação de Amostras/métodos , Fosfopeptídeos/química , Fosvitina/química , Sequência de Aminoácidos , Animais , Biocatálise , Galinhas , Hidrólise , Peptídeos/química , Espectrometria de Massas em Tandem , Tripsina/química
5.
Asian-Australas J Anim Sci ; 32(9): 1475-1481, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30744332

RESUMO

Objective: The objective of the present study was to investigate pork quality from Hereford×Berkshire (HB) female and intact male pigs reared outdoors in an alternative production system. Methods: Berkshire purebred sows were artificially inseminated, once in the fall and again in the spring of the following year, with semen from Hereford boars and managed free of antibiotics in an outdoor hoop structure until the last month of pregnancy, after which they were moved to a pasture-based unit of 0.8 hectares with individual lots with a farrowing hut, shade, and water ad libitum. Piglets were weaned at 4 weeks of age and housed in a deep-bedded hoop structure, grouped by sex. Animals were harvested at market weight of 125 kg, approximately 200 days of age. Hot carcass weight was collected at the time of the harvest. After 24 hours of refrigeration, carcass characteristics were measured. Longissimus dorsi samples collected from the right side loin. Loins were cut into 2.54-cm thick chops and were used to measure marbling score, color score, drip loss, and ultimate pH. Sensory panel tests were conducted as well at North Carolina State University. For pork characteristics and sensory panel data, trial and sex were included in the statistical model as fixed effects. Hot carcass weight was included in the model as a covariate for backfat thickness. Results: Neither the subjective nor the objective color scores displayed any differences between the boars and the gilts. No difference was found for pH and marbling score between trials or sexes. Gilts had a thicker backfat measurement at the last lumbar and a narrower longissimus muscle area measurement when compared to the boars. The only difference in the sensory characteristics was found between the trials for texture and moisture scores. Conclusion: Consumers were not able to detect boar taint under the condition of this study, which is that the intact males were reared outdoors. Additional trials would be necessary; however, based on the results of the present study, outdoor rearing can be suggested as a solution to the issue of boar taint.

6.
Asian-Australas J Anim Sci ; 30(9): 1207-1214, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28728401

RESUMO

Since the industrialization of swine production in the late 1900s, swine farms in the United States, as well as in Europe, have largely become consolidated. Pig farms became larger in size but fewer in number, with 91% of market pigs being produced by large operations with 5,000 or more pigs on-site in the US, and only 3% of the total utilized agricultural land representing organic farming. Such change in the market made it difficult for small farmers to stay competitive, forcing them to find alternative ways to reduce the cost of production and increase profit using the outdoor production system. In contrast to the indoor confinement system, outdoor production system uses pasture-based units and/or deep-bedded hoop structures that promote animal welfare and environmental sustainability with a lower capital investment. In accord with the growing concern for animal and environmental welfare and food safety by the consumers, small farmers practicing an outdoor production system are seeing increased opportunities for marketing their products in the pork niche market. Unlike the general belief that the reproductive and growth performance measures of the outdoor sows and piglets are poorer in comparison with the animals reared indoors, studies showed that there was no significant difference in the performance measures, and some traits were even better in outdoor animals. Improved reproductive and production traits can increase the sustainability of outdoor farming. Present study reviewed the recent studies comparing the performance measures, meat quality and health of indoor and outdoor animals, as well as the efforts to improve the outdoor production system through changes in management such as hut types and breed of animals.

7.
J Agric Food Chem ; 65(31): 6708-6716, 2017 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-28700223

RESUMO

The objective of this study was to identify metabolites that could be associated with oxidative stability of aged bovine muscles. Three muscles (longissimus lumbrum (LL), semimembranosus (SM), and psoas major (PM)) from seven beef carcasses at 1 day postmortem were divided into three sections and assigned to three aging periods (9, 16, and 23 days). Although an increase in discoloration was found in all muscles with aging, LL was the most color/lipid oxidative stable, followed by SM and PM (P < 0.05). Lower myoglobin and nonheme iron contents were observed in LL compared to those in SM and PM (P < 0.05). The HPLC-ESI-MS-based metabolomics analysis identified metabolites that were significantly responsive to aging and/or muscle type, such as acyl carnitines, free amino acids, nucleotides, nucleosides, and glucuronides. The results from the current study suggest that color and oxidative stability could be associated with aging but are also muscle-specific. Further studies determining the exact role of the identified metabolites in the color and oxidative stability of beef muscles are warranted.


Assuntos
Lipídeos/química , Carne/análise , Músculo Esquelético/química , Aminoácidos/química , Animais , Bovinos , Cor , Manipulação de Alimentos , Metabolômica , Músculo Esquelético/metabolismo , Nucleotídeos/química , Oxirredução , Mudanças Depois da Morte , Fatores de Tempo
8.
J Food Sci ; 82(4): 873-881, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28231393

RESUMO

Tissue culture and mycorrhiza applications can provide disease-free seedlings and enhanced nutrient absorption, respectively, for organic farming. Ginger (Zingiber officinale Roscoe) is rich in phytochemicals and has various health-protective potentials. This study was aimed at determining effects of tissue culture and mycorrhiza applications alone or in combinations in organic farming on phytochemical contents (total phenolics and flavonoids [TP and TF, respectively], gingerol and shogaol homologues, phenolic acids, and carotenoids) and antioxidant capacities (DPPH [2,2-diphenyl-1-picrylhydrazyl] radical scavenging, oxygen radical absorbance (ORAC), and iron-chelating capacities [ICC]) in solvent-extractable (Free) and cell-wall-matrix-bound (Bound) fractions of ginger rhizome and Free fraction of the leaves in comparison with non-organics. Concentrations of the phytochemicals and antioxidant capacities, except for carotenoids and ICC, were significantly higher in organic ginger rhizomes and leaves than in non-organics regardless of the fractions and treatments (P < 0.05). Mycorrhiza application in organic farming significantly increased levels of TP, TF, gingerols, and ORAC in the Free fraction of the rhizome (P < 0.05). Furthermore, the combined application of tissue culture and mycorrhiza significantly increased concentrations of TF and gingerols and ORAC in the Free fraction of the rhizome (P < 0.05), suggesting their synergistic effects. Considerable amounts of phenolics were found in the Bound fractions of the rhizomes. Six-gingerol, ferulic acid, and lutein were predominant ones among gingerols, phenolic acids, and carotenoids, respectively, in ginger rhizomes. The results suggest that organic farming with mycorrhiza and tissue culture applications can increase concentrations of phytochemicals and antioxidant capacities in ginger rhizomes and leaves and therefore improve their health-protective potentials.


Assuntos
Antioxidantes/análise , Micorrizas , Compostos Fitoquímicos/análise , Folhas de Planta/microbiologia , Rizoma/microbiologia , Zingiber officinale/microbiologia , Catecóis/análise , Ácidos Cumáricos/análise , Álcoois Graxos/análise , Flavonoides/análise , Zingiber officinale/química , Hidroxibenzoatos/análise , Luteína/análise , Agricultura Orgânica , Fenóis/análise , Folhas de Planta/química , Rizoma/química
9.
Food Chem ; 159: 106-15, 2014 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-24767032

RESUMO

The impacts of parboiling and wet-cooking, alone and in combination, on the concentrations of lipophilic antioxidants (vitamin E and γ-oryzanol), soluble (including proanthocyanidins and anthocyanins) and cell wall-bound phenolics, and antioxidant capacities in whole grain rice from six cultivars having different bran colours were investigated. Parboiling rough and brown rice increased the concentrations of lipophilic antioxidants in whole grain rice but decreased the concentrations of total phenolics and antioxidant capacities found in the soluble fraction. After hydrothermal processing of purple bran rice, the retention of extractable anthocyanins was low, but was high for simple phenolics. For proanthocyanidins found in red bran rice, the extractable oligomers with a degree of polymerization (DP) less than 4, increased up to 6-fold; while for oligomers with DP⩾4 and polymers, there was a significant decrease that was positively correlated with the DP and the temperature of the processing methods. The presence of hulls helped to retain water-soluble antioxidants during parboiling.


Assuntos
Antioxidantes/análise , Oryza/química , Antocianinas/análise , Antioxidantes/farmacologia , Manipulação de Alimentos , Quelantes de Ferro/farmacologia , Fenóis/análise , Fenilpropionatos/análise , Extratos Vegetais/análise , Tocoferóis/análise , Vitamina E/análise
10.
Biomed Res Int ; 2014: 598612, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24696857

RESUMO

This study was conducted to determine the effects of dietary cholesterol (CHO) and cholesterol oxidation products (COPs) on the induction of pathological lesions in rabbit liver tissues. Liver lesions were induced only when the levels of CHO and COPs in the diet were very high. The amount of CHO measured in the liver increased when dietary CHO was increased; by comparison, dietary COPs affected liver CHO amounts to a lesser extent. The TBARS (thiobarbituric acid reactive substances) value measured for the liver samples also increased when dietary CHO and COP levels were elevated, and the TBARS value was more strongly affected by the amount of COPs in the diet than by the amount of CHO. At 6 and 12 weeks, COP levels were the highest in the group that received 1.2 g CHO + 0.8 g COPs, followed by the 0.5 g CHO + 0.5 g COPs and 1.6 g CHO + 0.4 g COPs groups; the control (0 g) group showed the lowest COP levels among all groups. In this study, we found that not only dietary CHO but also COPs were involved in hypercholesterolemia induced liver lesions when the amount of CHO and COPs was high.


Assuntos
Colesterol na Dieta/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/patologia , Animais , Ácidos Graxos/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Oxirredução/efeitos dos fármacos , Coelhos , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
11.
Int J Mol Sci ; 14(6): 12593-606, 2013 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-23774834

RESUMO

Two studies were conducted to determine the effects of dietary cholesterol (CHO) and cholesterol oxides (COPs) on the development of atherosclerosis and the changes in fatty acid and blood characteristics in rabbits. In the first study, forty male New Zealand white rabbits were divided into 5 groups and fed commercial rabbit chow with no added CHO or COPs, 1 g CHO, 0.9 g CHO + 0.1 g COPs, 0.8 g CHO + 0.2 g COPs, or 0.5 g CHO + 0.5 g COPs per kg diet. In the second study, 24 male New Zealand White rabbits were divided into 3 groups and fed a diet containing 2 g CHO, 1.6 g CHO + 0.4 g COPs, or 1.2 g CHO + 0.8 g COPs per kg diet. All diets induced atherosclerotic lesions in the rabbits' ascending thoracic aorta. The serum CHO and triglyceride levels (p < 0.05) increased significantly with the increased levels of CHO in the diets. Dietary CHO or COPs did not influence high-density lipoprotein CHO levels. The ratio of saturated fatty acid to unsaturated fatty acid increased as the level of dietary CHO and COPs increased.


Assuntos
Aterosclerose/sangue , Aterosclerose/patologia , Colesterol na Dieta/efeitos adversos , Colesterol/sangue , Óxidos/metabolismo , Animais , Aorta Torácica/patologia , Vasos Coronários/patologia , Membrana Eritrocítica/metabolismo , Ácidos Graxos/sangue , Lipoproteínas HDL/sangue , Lipoproteínas LDL , Masculino , Coelhos , Triglicerídeos/sangue
12.
J Food Sci ; 77(9): C1000-4, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22897432

RESUMO

Hydrocarbons, gas compounds, and off-odor volatiles were determined for irradiated (0 or 5 kGy) commercial sausages with different fat contents (16% and 29%) during a 60-d storage period at 4 °C. Total of 4 hydrocarbons (C14:1, C15:0, C16:2, and C17:1) were detected only in irradiated sausages: the amount of C16:2 was the highest, followed by C17:1, C14:1, and C15:0. The concentrations of hydrocarbons decreased significantly (P < 0.05) with storage, but were still detectable at the end of 60-d storage. Irradiated sausages produced significantly higher amounts of CO than the nonirradiated ones. CH(4) was detected only in irradiated sausages. Dimethyl disulfide was detected only in irradiated sausages and its concentration decreased significantly (P < 0.05) with storage. Fat content of sausages showed a significant effect on the production and retention of hydrocarbons, gas compounds, and sulfur volatiles in irradiated sausages during storage. Some hydrocarbons (C16:2, C17:1, C14:1, and C15:0), CH(4) , and dimethyl disulfide were only found in irradiated sausages indicating that these compounds can be used as potential markers for irradiated sausages.


Assuntos
Irradiação de Alimentos/métodos , Hidrocarbonetos/análise , Produtos da Carne/análise , Compostos Orgânicos Voláteis/análise , Animais , Temperatura Baixa , Dissulfetos/análise , Ácidos Graxos/análise , Armazenamento de Alimentos , Odorantes/análise , Suínos , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Perus
13.
J Food Sci ; 76(1): C117-26, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21535639

RESUMO

Rice bran, a byproduct of the rice milling process, contains most of the phytochemicals. This study aimed at determining the concentrations of lipophilic, solvent-extractable (free), and cell wall-bound (bound) phytochemicals and their antioxidant capacities from brans of white, light brown, brown, purple, and red colors, and broccoli and blueberry for comparison. The concentrations of lipophilic antioxidants of vitamin E (tocopherol and tocotrienols) and γ-oryzanols were 319.67 to 443.73 and 3861.93 to 5911.12 µg/g bran dry weight (DW), respectively, and were not associated with bran color. The total phenolic, total flavonoid, and antioxidant capacities of ORAC (oxygen radical absorbance capacity), DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, and iron-chelating in the free fraction were correlated with the intensity of bran color, while variations of these in the bound fraction were less than those in the free fraction among brans. Compounds in the bound fraction had higher antioxidant capacity of ORAC than DPPH, relative to those in the free fraction. The bound fraction of light-color brans contributed as much to its total ORAC as the free fraction. Total proanthocyanidin concentration was the highest in red rice bran, while total anthocyanin was highest in purple brans. The predominant anthocyanin was cyanidin-3-glucoside. Red and purple brans had several fold higher total phenolics and flavonoids as well as ORAC and DPPH, from both free and bound fractions, than freeze-dried blueberry and broccoli. These results indicate that rice brans are natural sources of hydrophilic and lipophilic phytochemicals for use in quality control of various food systems as well as for nutraceutical and functional food application.


Assuntos
Antioxidantes/análise , Fibras na Dieta/análise , Flavonoides/análise , Oryza/química , Fenóis/análise , Sementes/química , Antocianinas/análise , Antocianinas/química , Antocianinas/economia , Antioxidantes/química , Antioxidantes/economia , Parede Celular/química , Flavonoides/química , Flavonoides/economia , Aditivos Alimentares/análise , Aditivos Alimentares/química , Aditivos Alimentares/economia , Indústria de Processamento de Alimentos/economia , Sequestradores de Radicais Livres/análise , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/economia , Interações Hidrofóbicas e Hidrofílicas , Resíduos Industriais/análise , Resíduos Industriais/economia , Quelantes de Ferro/análise , Quelantes de Ferro/química , Quelantes de Ferro/economia , Fenóis/química , Fenóis/economia , Fenilpropionatos/análise , Fenilpropionatos/química , Fenilpropionatos/economia , Pigmentação , Polifenóis , Proantocianidinas/análise , Proantocianidinas/química , Proantocianidinas/economia , Solubilidade , Especificidade da Espécie , Vitamina E/análise , Vitamina E/química , Vitamina E/economia
14.
Food Chem ; 128(2): 299-307, 2011 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-25212135

RESUMO

The antioxidant effects of meat fractions from chicken breast and beef loin were compared. Five meat fractions - homogenate (H), precipitate (P), supernatant (S), high-molecular-weight (HMW) and low-molecular-weight (LMW) fractions - were prepared from chicken breast or beef loin. Each of the fractions were added to a phospholipid liposome model system containing catalysts (metmyoglobin, ferrous and ferric ion) or iron chelating agents to determine the effects of each fraction on the development of lipid oxidation during incubation at 37°C for 120min. All fractions from chicken breast showed stronger antioxidant effects against iron-catalyzed lipid oxidation than those from beef loin. Iron chelating capacity of water-soluble LMW and water-insoluble (P) fractions from both meats were responsible for their high antioxidant capacities. High concentration of myoglobin, which served as a source of various catalysts, was partially responsible for the high susceptibility of beef loin to lipid oxidation. Storage-stable ferric ion reducing capacity (FRC) was detected in all fractions from both meats, and was a rate-limiting factor for lipid oxidation in the presence of free ionic iron. Higher antioxidant capacity and lower myoglobin content in chicken breast were primarily responsible for its higher oxidative stability than beef loin. DTPA-unchelatable compounds, such as ferrylmyoglobin and/or hematin were the major catalysts for lipid oxidation in beef loin, but free ionic iron and storage-stable FRC also played important roles during prolonged storage.

15.
J Agric Food Chem ; 58(1): 600-5, 2010 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-19904983

RESUMO

Chicken breast and beef loin were ground, and no, NaCl, NaCl+myoglobin, NaCl+Fe(II), or NaCl+Fe(III) additions were made; patties were then prepared. Half of the patties were packaged in oxygen-permeable bags and stored at 4 degrees C for 10 days, and the other half were cooked in a 95 degrees C water bath to an internal temperature of 75 degrees C, packaged in oxygen-permeable zipper bags, and stored at 4 degrees C for 7 days. The oxidative stability of raw and cooked chicken breast and beef loin were determined during storage. Chicken breast was more resistant to various exogenous oxidative factors than beef loin: addition of NaCl did not increase TBARS values and nonheme content of raw chicken breast, but significantly increased those of raw beef loin patties during storage. Addition of NaCl+Mb did not affect lipid oxidation in raw chicken breast patties, but decreased the TBARS of beef loin during storage. Addition of NaCl+Fe(III) or NaCl+Fe(II) increased the TBARS values of both raw chicken breast and beef loin during storage, but the increase was greater in beef loin than in chicken breast. The TBARS values of all cooked chicken breast and beef loin increased during 7 days of storage, but the increases in cooked chicken patties were significantly smaller than those of cooked beef loin patties with the same treatments. Addition of NaCl and cooking caused severe degradation of myoglobin, leading to a significant increase in free ionic iron content in beef loin. It is suggested that free ionic iron is the major catalyst for lipid oxidation, and the low "storage-stable and heat-stable" ferric ion reducing capacity in chicken breast were responsible for the high oxidative stability for raw and cooked chicken breast compared with beef loin under prooxidants, cooking, and storage conditions.


Assuntos
Compostos Férricos/química , Compostos Ferrosos/química , Manipulação de Alimentos , Lipídeos/química , Carne/análise , Mioglobina/química , Cloreto de Sódio/química , Animais , Bovinos , Galinhas , Oxirredução
16.
J Agric Food Chem ; 54(25): 9535-43, 2006 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-17147443

RESUMO

The structural isomers formed by the homogeneous rhodium-catalyzed isomerization of several vegetable oils have been elucidated. A detailed study of the isomerization of the model compound methyl linoleate has been performed to correlate the distribution of conjugated isomers, the reaction kinetics, and the mechanism of the reaction. It has been shown that [RhCl(C8H8)2]2 is a highly efficient and selective isomerization catalyst for the production of highly conjugated vegetable oils with a high conjugated linoleic acid (CLA) content, which is highly desirable in the food industry. The combined fraction of the two major CLA isomers [(9Z,11E)-CLA and (10E,12Z)-CLA] in the overall CLA mixture is in the range from 76.2% to 93.4%. The high efficiency and selectivity of this isomerization method along with the straightforward purification process render this approach highly promising for the preparation of conjugated oils and CLA. Proposed improvements in catalyst recovery and reusability will only make this method more appealing to the food, paint, coating, and polymer industries in the future.


Assuntos
Óleos de Plantas/química , Ródio/química , Catálise , Cromatografia Gasosa , Isomerismo , Ácidos Linoleicos/química , Ácidos Linoleicos Conjugados/química , Espectroscopia de Ressonância Magnética , Polímeros/química
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