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1
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
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A comparison of human and electronic nose responses to flavour of various food products of different degree of lipids oxidation

100%
Mildner-Szkudlarz S., Zawirska-Wojtasiak R., Korczak J., Jelen H. H.
Polish Journal of Food and Nutrition Sciences
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2007
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tom 57
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nr 2
195-202
This paper investigates the effectiveness of electronic nose with subsequent principal component analysis (PCA) treatment of data for differentiation of food samples of varied odour quality caused by lipid oxidation. Samples were evaluated for off-flavours with an electronic nose and a sensory analysis and for Totox value. Volatile compounds of fresh samples and samples subjected to storage test at 60°C were isolated with a static headspace technique. The results suggest that the electronic nose could help to supplement the sensory analysis. Models based on partial least-squares analysis were able to predict the oxidized flavour attribute of samples, with correlation coefficients ranging from 0.66 to 0.99. Based on elaborated methods and data treatment with PCA it was possible to distinguish between different food samples and monitor the formation of off-flavours associated with lipid oxidation.
2
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Changes of lipid oxidation degress and their influence on protein nutritive value of frozen meat products

84%
Hes M., Korczak J., Gramza A.
Polish Journal of Food and Nutrition Sciences
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2007
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tom 57
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nr 3
323-328
The aim of the study was to determine the influence of oxidation degree on available lysine and methionine content and protein digestibility in meat products with added antioxidants (rosemary extracts, green tea extracts, BHT) stored under frozen conditions. Oxidation degree of lipid using peroxide value (PV), anisidine value (AV), thiobarbituric acid reactive substances (TBARS), and Totox coefficient was controlled and protein digestibility and content of available lysine and methionine were determined periodically. Results showed an increase in lipid oxidation during storage. The highest values for the applied measurement of oxidation were observed in the control sample without antioxidants. The added antioxidants slowed down lipid oxidation to a significant extent. In control samples, the content of available lysine and methionine was reduced by 53% and 75% respectively, whereas protein digestibility by 12.5% at the end of storage. Inhibition of lipid oxidation products formation by the addition of antioxidants, limited significantly lysine and methionine losses and reduction of protein digestibility. The application of antioxidants extended stability and protected biological protein value of the meat products examined.
3

Evaluation method of labelling of vegetable oils on the Olsztyn market

84%
Ambrosewicz M., Tanska M., Rotkiewicz D.
Polish Journal of Natural Sciences
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2012
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tom 27
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nr 1
The aim of the study was to evaluate the labelling of selected vegetable oils and the provision of required and up-to-date information about their quality. Eight vegetable oils, including 2 rapeseed oils and 6 mixtures, were used as the study material. Evaluation of labelling involved analysing information provided on oil labels in terms of its compliance with the requirements set out in Tłuszcze roślinne... PN-92/A-86932, particularly as to whether it was up-to-date and whether it complied with the quality determined in the analyses. The quality of oils was described by the degree of hydrolysis (acid value), degree of oxidation (peroxide number, anisidine number, diene and triene content) and fatty acid composition. Labelling of the analysed vegetable oils was found to be unsatisfactory since not all the required information was provided; for example, there was no information about the preservation or flavouring of the oils, only sporadically was any information provided on vitamin content (1 out of 8 oils) and other information was missing. Labelling was also unsatisfactory in terms of the accuracy of information because it did not provide data about the ratio of omega-6 and omega-3 acids or about how long an oil had been stored - which is associated with the content of fat oxidation products. It was established in analyses of oil quality that the acid value and the peroxide number did not exceed the minimum adopted for refined oils Oleje i tłuszcze... PN-A-86908:2000) and that the values of anisidine number in 3 oils were close to, or exceeded, the value mentioned in the standard. The percentage of saturated fatty acids complied with the producers' claims, whereas the percentage of monounsaturated fatty acids was below standard for one oil and the percentage of polyunsaturated fatty acids was below standard for two oils.
4

Biochemical indices in blood and tissues of turkeys fed feed mixtures containing fat of different oxidation degree

84%
Koncicki A., Krasnodebska-Depta A., Zdunczyk Z., Jankowski J., Wroblewska M., Falkowska A.
Polish Journal of Veterinary Sciences
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2000
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tom 03
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nr 2
Four groups of turkeys were fed mixtures containing fat of different peroxide values, 5, 50, 100 and 150 mEq O2/kg, respectively, for four months; the fat content over successive months was 2, 3, 4 and 5%. Every month blood samples were collected from 12 birds randomly selected from each group. Moreover, six turkeys from each group were slaughtered to collect samples of the liver, breast muscles and intestines (duodenum). The study revealed, that oxidised fat added to feed mixture reduced considerably the uric acid serum level and vitamin E content in the the liver. There was no indication, that peroxide values of fat in diet had any influence on the serum content of glucose, triglycerides, cholesterol, calcium and phosphorus or on the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), alkaline phosphatase (AP), lactate dehydrogenase (LDH) and creatine kinase (CK). Oxidised fat in diet, cansed a decrease of ALT and LDH activity in the turkey liver and an increase of LDH and CK activity in breast muscles. The results obtained in this study suggest that the diets applied did not cause significant disorders in the organism homeostasis, which might indicate that the adaptation mechanism of turkeys is activated after the diets had been followed for a long time.
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