Browsing by discipline "Biotechnology (EYT) (Food Biotechnology)"
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(2009)The present study was conducted to test the effect of an essential oil blend containing thymol and cinnamaldehyde on chicken pancreatic enzyme activities. Essential oils are oils from plant origin and have become an important alternative in animal nutrition after the European Union banned the use of antibiotics as growth promoters. Some previous studies have indicated that essential oils may stimulate the secretion of digestive enzymes, and thereby have a positive effect on the digestion and absorption of nutrients (Windisch et al. 2008). Pancreas samples originated from 20- and 28-day old Ross male chickens, that were fed with wheat soybean diets supplemented (or not) with the essential oil blend. Optimization of the colorimetric assays for detecting the enzyme activities in the supernatants of pancreatic homogenates was carried out. The ?-amylase, trypsin, chymotrypsin and lipase activities were expressed as U per mg of protein. The activity results were compared with previously collected digestibility and performance results. The addition of the essential oil blend at the applied concentrations to chicken diet did not have a significant effect on the activities of the chicken pancreatic enzymes. Overall, the enzyme activities did not show strong correlations to chicken performance or nutrient digestibilities. However, there were significant differences (P < 0.05) in the lipase and trypsin activities between the 20- and 28-day old chickens. It can be concluded that the studied essential oil blend did not stimulate pancreatic enzyme activities at the tested conditions. However, further studies are needed to explain the effect of the dietary supplement of essential oils on chicken digestion.
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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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