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Extending of shelf life of chilled fish products
PFLUG, Róbert
This diploma thesis was focused on the possibilities of extending the shelf-life of fish products by dipping containing seven commercial additives. ANTIBAK, MIC STAB, Bakont, SEA-F75, Misocarine LR, SAFE A Plus and AMX liquid. The effectiveness of these substances on the extending of shelf-life was evaluated on the basis of tests of TVC (total viable count), level of fat and protein oxidation, determination of nutritional parameters of muscle, and finaly sensory analysis. Experimental species were 2 important commodities for the Czech aquaculture rainbow trout (Oncorhynchus mykiss) and common carp (Cyprinus carpio). The project was divided into 6 sub-stages. During testing was the initial number of aditives (7) limited by stepwise selection for 2 preparations. Namely Bakont and AMX liquid, which were tested further on trout (filet with skin and scales) and carp (filets with skin without scales) chilled bulk and chilled packaged under vakuum. For trout was studied antimicrobial effect of dipping on eviscerated fish with the head with- or without gills. Treated trout fillets in bulk and vakuum-packed showed significantly less abundance of muscle mikroflora. In the case of carp fillets chilled bulk we can not say that the bath had influence on the CMP in meat. However, the combination of dipping and vakuum packaging was singnificantly different between the control and product Bakont. AMX liquid was not applied in this case in sufficient dose or in sufficient time to carp muscle. A positive finding is that the application of the aditives to the product "eviscerated trout with head" it does not matter, whether the gills are left in fish or not. However, in all cases the analysis of the presence of pathogens Escherichia coli, Salmonella spp. or Listeria monocytogenes were negative. From the results of sensory analysis can be concluded, that the substances contained in aditives are not reflected in the sensory properties of tested fish.
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Impact of alternative feed on growth, yield and sensory evaluation of flesh of salmonids.
PFLUG, Róbert
The bachelor thesis evaluates the impact of alternative feed on growth, yield and sensory evaluation of flesh of salmonids. The technology "finishing feeding" and its impact on these indicators was evaluated by a feeding test conducted in trout farm in Annin (Klatovské rybářství a.s.). The experimental species was brook trout (Salvelinus fontinalis L.) with average weight of 156 ? 4,91 g. The test was carried out for 135 days and there were 2 diets. Diet A (rapeseed oil, RO) or B (fish oil, FO) or their combination (45RO:90FO; 90RO:45FO). Each treatment was carried out in duplicate. After 45, 90 days and at the end of the test, evaluation of production characteristics, yield and sensory evulation of fish muscle was carried out. Fish oil replacement by rapeseed oil had no effects on fish survival, growth, feed conversion and yield. After 45 days (first sensory evoluation), flesh of fish fed diet with rapeseed oil was better senzory evaluated than fish fed fish oil diet. However, the later sensory evaluation didn?t show any statistical differences among the treatments.
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