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1

Effect of modified atmosphere packaging on the course of physical and chemical changes in chilled muscle tissue of silver carp (Hypophthalmichthys molitrix, V.)

100%

Jezek F. , Buchtova H.

Polish Journal of Veterinary Sciences

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2012

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tom 15

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nr 3

EN

The effect of two types of modified atmosphere (MA1: 69% N2, 25% CO2, 5%O2, 1% CO; MA2: 70% N2, 30% CO2) on changes in physical and chemical parameters (pH, aw - water activity, TVBN - total volatile basic nitrogen, TMA - trimethylamine, FFA - free fatty acids, PV - peroxide value, TBA - thiobarbituric acid) in muscle tissues of the silver carp was monitored in the study. The samples were stored at temperatures +2 ± 2oC for 18 days. Changes in gas volumes (CO2 and O2) in MAs were also monitored. CO2 levels increased in MA1 but decreased in MA2. At the end of 18 days of storage, a significantly (P < 0.01) lower water activity (aw) levels were found in samples packaged under MA1, in contrast to samples packaged under MA2 where water activity values showed considerable fluctuation. Variations in pH values in the two types of MA showed similar trends. Sample pH gradually decreased until day 9 of storage. On day 11, muscle tissue pH increased markedly and then began to decrease again. The overall decrease in pH values was more profound in samples packaged under MA1. TVBN and TMA levels in samples packaged under the two types of MAs remained almost identical until day 9 of the experiment. Later, however, significantly (P < 0.01) higher levels of both parameters were found in muscle tissues packaged under MA1. FFA concentrations in silver carp samples in MA1 were significantly lower (P < 0.01) throughout the experiment. The PV increased significantly in both muscle samples tested. Greater fluctuations in this parameter’s values throughout the experiment were observed in samples packaged under MA2. Faster rates of oxidation (P < 0.01) were found in samples packaged under MA1 starting on day 9. Maximum TBA values in MA1 and MA2 were observed on days 14 and 18 of the experiment, respectively. From the course of proteolytic and oxidative changes point of view, the more appropriate combination of gases for silver carp storage seems to be the mixture of 70% N2 and 30% CO2 (MA2), which allows for muscle storage of up to 9 days. We recommend TVBN as a suitable indicator of freshness, and TBA assay as a suitable indicator of the extent of oxidative processes.

2

Quality indicators of roe deer (Capreolus capreolus L.) venison in relation to sex

80%

Dominik P. , Salakova A. , Buchtova H. , Steinhauser L.

Polish Journal of Food and Nutrition Sciences

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2012

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tom 62

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nr 3

EN

Quality of roe deer venison was evaluated based on chemical composition, technological parameters, pH values and colour. Loin (M. longissimus dorsi) and leg (M. gluteus medius) samples were taken from 14 males and 11 females of roe deer (Capreolus capreolus L.). Highly signifi cant differences between samples from the two parts of body were found only in pH (120 h post mortem). Highly signifi cant differences between sexes were found in colour values of L* in leg samples at 72 h and loin samples at 120 h, and of a* in loin samples at 72 h. The content of haem pigments ranged from 2.56 to 3.84 mg/g, highly signifi cant differences were found in leg samples. Dry matter content was higher in male venison compared with female venison. Highly signifi cant differences between sexes were found in loin fat content (p<0.05) and in total collagen content (p<0.01) in leg muscles. The fat content, total and pure proteins and collagen content were higher for males. In both sexes, statistically signifi cantly higher drip loss was found in loin tissues, while cooking loss was higher in leg samples. With respect to sex differences, drip loss of both muscle types was higher in male roe deers, while cooking loss was higher only in loin muscle of females. In our experiment, hardness in excess of 40.00 N was found out in roe deer venison. The highest maximum hardness was found in male leg.

3

Selenium from Se-enriched lactic acid bacteria as a new Se source for growing-finishing pigs

61%

Svoboda M. , Salakova A. , Fajt Z. , Ficek R. , Buchtova H. , Drabek J.

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nr 3

EN

The goal of the trial was to determine the efficacy of Se from Se-enriched lactic acid bacteria in accumulation of Se in the muscle tissue and to evaluate its effect on meat quality in finisher pigs. In group I (n = 12) the feed was supplemented with inorganic sodium selenite, in group II (n = 12) with Se from Se-lactic acid bacteria, in group III (n = 12) with Se from Se-enriched yeast and pigs in group IV (n = 11) were fed non-supplemented basal diet. The experimental feed mixtures were supplemented with 0.3 mg Se per kg and were fed for a period of 3 month before slaughter. The use of Se from Se-enriched lactic acid bacteria resulted in comparable accumulation of Se in the muscle tissue as with sodium selenite, and in lower accumulation in comparison with Se from Se-enriched yeast. We did not find any differences in parameters of meat quality among experimental groups. It is concluded that Se from Se-enriched lactic acid bacteria has a comparable accumulation in the muscle tissue as sodium selenite and it does not negatively influence the meat quality.