RESUMO
The aim of this study was to evaluate the influence of different packaging materials [standard foil: BOPP (biaxially oriented polypropylene)/PET (polyester)/PE (polyethylene) for upper layer, and APET (polyethylene terephthalate)/PE for bottom layer; foil 1: PP (polypropylene)/PET/PE/EVOH (ethylene-vinyl alcohol copolymer)/PE upper layer, and PP/PE/EVOH/PE bottom layer; foil 2: PP/PET/PE/EVOH/PE upper layer, and PA (polyamide)/EVOH/PE bottom layer; foil 3: PP/PET/PE upper layer, and PA/EVOH/PE bottom layer; foil 4: PP/PET/PE upper layer, and PA/PE bottom layer; foil 5: PP upper layer, and PP/PP bottom layer] on the quality of 3 different ripening rennet cheeses packed under different modified atmosphere (MAP) conditions as reflected in particular physicochemical, microbiological, and sensorial changes. The changes were monitored during a period of 90 d of storage at 2°C or 8°C. For Gouda cheese, CO2 content of the headspace of the packages was in the range 35% to 45%, whereas for Maasdamer and Sielski Klasyczny cheeses it was 55% to 65%. Three-way ANOVA showed that the foil type influenced the moisture content of Gouda cheese stored for 90 d at 2°C and for Sielski Klasyczny cheese at 8°C, whereas the moisture content was not dependent on MAP conditions during storage. Moreover, the foil type had a significant effect on free fatty acid changes for Gouda and Sielski Klasyczny cheeses stored at 2°C for 90 d. Sensory attributes changed significantly over storage time at 2°C for all studied cheeses as affected by foil type, whereas there was no effect of MAP conditions. In general, the cheeses packed in standard foil and foil 4 were characterized by the highest values of mean sensory attributes. Time was the most significant factor influencing most changes in physicochemical and sensory attributes of cheeses stored at 2°C and 8°C. The storage temperature did not affect the moisture of the samples during storage. In general, we found an increase in the pH value during storage regardless of storage temperature. It was possible to decrease the thickness of the packaging material from initial 103 and 250 µm (standard foil; lid and bottom, respectively) to 98 and 100 µm (foil 4) without affecting sensory attributes of the product.
Assuntos
Queijo , Animais , Queijo/análise , Polipropilenos , Embalagem de Alimentos , Embalagem de Medicamentos , ClimaRESUMO
Food business operators must include the results of shelf life testing in their HACCP plan. Ready-to-eat preservative-free meat products enriched with blood plasma are an unfathomable area of research in food safety. We tested modified atmosphere (80% N2 and 20% CO2) and vacuum packaged RTE preservative-free baked and smoked pork bars with dried blood plasma for Aerobic Plate Count, yeast and mould, lactic acid bacteria, Staphylococcus aureus, Enterobacteriaceae, Escherichia coli, and Campylobacter spp., and the presence of Listeria monocytogenes and Salmonella spp. during storage (temperatures from 4 to 34 °C) up to 35 days after production. The obtained data on the count of individual groups of microorganisms were subjected to analysis of variance (ANOVA) and statistically tested (Student's t-test with the Bonferroni correction); for temperatures at which there were statistically significant differences and high numerical variability, the trend of changes in bacterial counts were visualised using mathematical modelling. The results show that the optimal storage conditions are refrigerated temperatures (up to 8 °C) for two weeks. At higher temperatures, food spoilage occurred due to the growth of aerobic bacteria, lactic acid bacteria, yeast, and mould. The MAP packaging method was more conducive to spoilage of the bars, especially in temperatures over 8 °C.
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The aim of this study was to investigate the course of glycogenolysis, ATP breakdown and fragmentation of myofibrillar proteins in the semitendinosus muscle of a progeny of Limousin×Holstein-Friesian (LMx) and Charolaise×Holstein-Friesian (CHx) (bulls and steers) and to describe the changes in the above parameters over time and its relationship with beef texture. The hypothesis that beef from bulls and steers of different crossbreeds required the same ageing time to achieve satisfactory tenderness was also tested. Cattle crossbreeding did not affect the amount of muscle glycogen, and castration did not differentiate it until 3 h post-mortem. The interaction between crossbreeding and castration was found, and the highest shear force values were observed in CHx bulls, whereas the lowest was in CHx steers. Beef obtained from CHx was found to be more predestined to short ageing, and LMx required longer ageing to achieve good tenderness. The R-values more strongly influenced subsequent beef texture than pH values.
Assuntos
Músculo Esquelético/química , Carne Vermelha/análise , Resistência ao Cisalhamento , Trifosfato de Adenosina/metabolismo , Animais , Bovinos , Manipulação de Alimentos/métodos , Glicogênio/análise , Hibridização Genética , Concentração de Íons de Hidrogênio , Masculino , Proteínas Musculares/metabolismo , Miofibrilas/química , Orquiectomia/veterinária , Fatores de TempoRESUMO
Different harvesting and preservation methods of Virginia fanpetals herbage were evaluated, based on the chemical composition and digestible organic matter (OM) content (D-value) of silage fed to adult sheep, the intake and digestibility of silage, and the performance of young cattle. The following harvesting methods were compared: direct-cut harvesting with a precision-cut forage harvester (DC), harvesting after field wilting with a precision-cut forage harvester (WC) or a round baler (WRB). The silage was fed for 81 days to 24 Polish Holstein Friesian (HF) bulls, as the sole forage supplemented with 3.0 kg of concentrate/head/day. Harvesting methods affected the density (p < 0.001) and water-soluble carbohydrate (WSC) content (p = 0.047). Differences were found among the groups in the digestibility coefficients of OM (DC-73.7, WC-78.9, WRB-79.9%) (p = 0.007), and crude protein (CP) (69.8%, 77.1%, 78.5%, respectively) (p < 0.001). Dry matter intake (DMI) reached 8.38 kg (DC), 8.74 kg (WC) and 7.21 kg (WRB). Live weight gain (LWG) differed (p < 0.001) among groups (0.939, 1.033, 0.813 kg/day, respectively). The feed conversion ratio (FCR) tended to improve in WC (8.66 kg DMI/kg LWG) (p = 0.08). The highest-quality silage was produced in group WC, and it could be successfully fed to growing bulls as the sole forage.
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OBJECTIVE: The objective of this study was to determine the effects of age and gender (bull vs steer) on feeding behavior parameters in young beef cattle fed grass silage. METHODS: The study was conducted on 180 young beef cattle at 7 to 18 mo of age. The experimental materials comprised 90 bulls produced by commercial crossing of Polish Holstein-Friesian cows with Charolais, Limousin and Hereford bulls (30 animals of each breed) and 90 steers of the same genotypes. The animals had ad libitum access to grass silage; the concentrate was fed separately, in feed stations. They received 28 g dry matter of concentrate per kg of metabolic body weight per day. Bunk visit data and silage intake for all experimental animals were recorded individually using the Roughage Intake Control system (5 feed bunks per 15 animals). RESULTS: Age and gender (bull vs steer) exerted significant effects on the feeding behavior of young beef cattle. The frequency of bunk visits and meal frequency decreased, whereas the feeding rate of silage, and the average duration and size of a single meal increased with age (p<0.01). Bunk attendance and meal frequency were higher (p<0.01) in steers than in bulls (49.1 vs 37.4 visits/d, and 8.63 vs 7.99 meals/d, respectively). Daily feeding time was longer in steers than in bulls (102.3 vs 100.3 min/d, respectively), but the feeding rate of silage was lower in steers, and their meals were smaller in size and shorter in duration (p<0.01). Daily silage dry matter intake was higher (p<0.01) in bulls than in steers (4.62 vs 4.47 kg/d, respectively). CONCLUSION: The results of this study indicate that age and gender (bull vs steer) exerted significant effects on the feeding behavior of young beef cattle.
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The effect of high hydrostatic pressure (HHP) (450-550-650â¯MPa/5-10-15â¯min) on polyphenols profile of purée obtained from commercial tomato varieties (Maliniak, Cerise, Black Prince and Lima) was investigated. Individual polyphenols, total phenolic index (TPI) were quantified using a mass spectrometer (HPLC-MS/MS). Photochemiluminescence (PCLACW), cyclic voltammetry (CV) and ferric reducing antioxidant power (FRAP) assays were used to determine the antioxidant capacity of the hydrophilic extract. The results demonstrated that at certain processing conditions, HHP may enhance or decrease the nutritional quality of tomato purée. However, the tomato variety was a key factor influencing the polyphenols profile and the antioxidant capacity. A significant positive correlation was found among TPI, FRAP or CV parameters and the concentration of caffeic, ferulic, sinapic and p-coumaric acids, and epicatechin. On the other hand, significant positive correlation was observed among antioxidant capacity (PCLACW), TPC, rutin and naringenin concentration as well as chlorogenic and isochlorogenic acids.
Assuntos
Antioxidantes/análise , Manipulação de Alimentos/métodos , Fenóis/análise , Solanum lycopersicum/química , Antioxidantes/química , Catequina/análise , Cromatografia Líquida de Alta Pressão , Ácidos Cumáricos/análise , Medições Luminescentes , Valor Nutritivo , Fenóis/química , Polifenóis/análise , Pressão , Espectrometria de Massas em TandemRESUMO
The objective of this study was to determine the usefulness of live animal measurements in estimating the intramuscular fat (IMF) content of m. longissimus thoracis (MLT) in beef cattle. Live animal measurements were performed in young crossbred bulls (96) and steers (59), the offspring of Holstein-Friesian (HF) cows and beef bulls (Limousin, Hereford and Charolais), at the end of the fattening period. The content of intramuscular fat was determined in samples from MLT by chemical analyses. A prediction model was developed by stepwise regression. In the validation model, the values of R2=0.74, RMSE=0.37% were determined. The results indicate that selected biometric (chest width, chest girth) ultrasound measurements (thickness of subcutaneous rump and back fat) and selected blood parameters (triglycerides) can be used to predict IMF content with satisfactory precision and accuracy. The analyzed parameters could constitute a valuable tool in the process of selecting beef quality traits and determining the slaughter value of young beef cattle.