Browsing by Subject "modified atmosphere packaging"
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(2011)Polyphenolic compounds occurring naturally in knotwood of plants are known to have antimicrobial effects. The knots (i.e. the branch bases inside tree stems) and outer branches in pine trees contain a remarkably high concentration of phenolic stilbenes, while lignans are the major phenolic constituents of spruce knots. Large amount of these phenolic compounds can be extracted from wood knots at pulp and paper mills where their presence is undesirable. In Finland, marinating of broiler meat is done not only to increase or add value to the meat, but also to enhance the safety and shelf-life. These products are usually packed under a modified atmosphere for further protection against spoilage microorganisms. However, studies have revealed that addition of marinades to poultry products do not have an inhibitory effect on either some psychrotrophic anaerobic bacteria, such as Brochothrix thermosphacta or lactic acid bacteria associated with spoilage. Also, the activity of pathogenic Campylobacter jejuni is not affected by marinating. The objective of this study was to investigate the inhibitory and lethal activities of extracts from spruce (Picea spp.) and pine (Pinus spp.) knotwood and outer branches that are dissolved in ethanol against the spoilage microorganisms in modified atmosphere packaged marinated broiler products. Modified atmosphere packaged broiler products were separately inoculated with ‘normal’ marinades, marinades with 70% ethanol, marinades with a mixture of spruce and pine extracts dissolved in 70% ethanol or mixture of spruce and pine extracts in powder form. The bacterial colony forming units per gram obtained from each of the samples were analysed on de Man Rogosa and Sharpe agar at days 1, 6, 12 and 15. The results showed that there were significant differences in bacterial colony forming units per gram (P <0.05) between packages with ‘normal’ marinades and packages with extracts added to their marinades on the 12th and 15th day. It can be concluded that the addition of extracts from spruce and pine knotwood to marinades significantly retarded growth of spoilage microorganisms during the 15 day test period. However further research is warranted to characterise and establish the safety and suitability of the compound(s) in spruce and pine knotwood extracts that are responsible for inhibitory or lethal activity against the microbes that may be present in marinated poultry meat.
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(2021)Microbiological and sensory quality are the main attributes to estimate the shelf life of the broiler chicken meat. Both can be affected by MAP (modified atmosphere packaging). Even though there has been a lot of research on MAP, the same gas mixture might not work even for similar products. The first aim of this study was to determine the best possible gas mixture for the microbial and sensorial quality of the chicken fillets. Secondly, to find out if a pre-treatment affects the functionality of the MAP and if the packaging material influences gas stability. Three different kind of chicken breast fillets were used as samples: natural, slightly salted, and marinated. Each of the fillets were packed in five different gas mixtures (1–5) which were combinations of carbon dioxide (CO2) and nitrogen (N2). Samples were packed in two different packaging materials where one of them had a better gas barrier than the other. The samples were stored in cold room (5ºC) for 21 days. Microbiological measurements were carried out for four days and quality measurements for three days. Quality analyses measured the water holding capacity, pH, colour, smell, tenderness of the meat, packaging collapse and gas stability. According to our results we could not differentiate a gas mixture that would fit best for all differently pre-treated samples. Gas mixture (3) prolonged the shelf life only with natural fillets. Fillets packed to gas mixture (3) had lower pH, but higher drip and cooking losses. Higher CO2 content in the gas mixture was connected to greater packaging collapse. Gas mixtures (1), (4) and (5) maintained the quality characteristics best. Pre-treatment influenced the tenderness of the fillets, microbiological quality, and the gas composition. Packaging material had a slight effect on the gas composition but there was no significant difference at the end of the storage period.
Now showing items 1-2 of 2