Evaluation and comparison of durability of polycyclic aromatic hydrocarbon compounds (PAHs) and its relation to the lipid content in smoked fishes, Silver carp (Hypophthalmichthys molitrix), Rutilus frisii kutum and Herring (Alosa caspia)

Cold smoking method is one of the commonest ways for fish smoking. It is done by the smoke that is the result of burning hard and soft woods is smoking rooms. Smoke includes a number of chemical constructs and its main part is poly aromatic hydrocarbons. More than one hundred kinds of these constructs are recognized in smoke that is produced from saturated hydrocarbons resulted from the solution of the woods Ligno cellulose in high temperature and lack of oxygen conditions. The high poisoning potentials and carcinogenic features sixteen constructs among them are proved and observed on humans. In this research, the PAH compounds were identified and observed in a three month period after smoking and during storing among three types of smoked fishes Silver carp and Caspian sea Sefid and herring. They are the most produced and consumed smoked fish in Iran. To find the relationship between the concentrations of PAH constructs and the amount of lipid in fish, first, the amount of lipid were determined separately in the skin and flesh of 30 samples of each type. The method used was Bligh and Dyer (1959). PAH compounds derivation were made for all skin and flesh samples smoked fish using organic solvents with Soxeleh and the derived samples were injected to gas chromatography (GC) by Hamilton injectors for determining their components quality and their quantity. The height of the used column was 25 meters and its diameter was 0.32 mm with the silica filler, nitrogen gas as carrier and flame ionization detector (FID) that are special for these constructs. For data analysis, Statistical tests were used by computer soft ware identified that the difference in the amount of lipid within the flesh and skin of each species and also among each other is significant. The largest amount was in Herrings flesh and skin, 18.74% in skin and 14.47% in flesh. The least amount in the skin 4.19% and the flesh 3.10% of Sefid. The amount in Silver carp was 13.28%in skin and 8.16% in flesh. The examination of the PAH compounds in smoked fish showed that is carcinogenic compounds; exist in these in these fish with different quantities in each. It seems that its amount is directly related to the amount of their lipid. The amount is different in flesh and skin. One of the most important reasons is the direct content of smoke and the concentration of lipid in tissues of all three types. The maintenance of the smoked fish for three months showed that most of PAH compounds were solved and their density decreased. The changes in density within time in different in each type and in flesh and skin. The amount of their receiving in human through the consumption of the smoked fish depends on the resulted density, the way and the amount of consumption and now we can determine and execute standards for the maximum dosage per day and per month regarding effective factors.

Evaluation of Several Commercial Algicides for Control of Odor-producing Cyanobacteria

The production of certain odorous metabolites is an undesirable attribute of cyanobacteria (blue-green algae) growth in aquaculture ponds [e.g., channel catfish(Ictalurus punctatus)] and in drinking water reservoirs. The most common odorous compounds encountered in catfish aquaculture are geosmin (trans-1,10-dimethyltrans-9-decalol) and 2-methylisoborneol(exo-1,2,7,7-tetramethylbicyclo[2.2.1]heptan-2-ol). These compounds are also frequently encountered worldwide in reservoirs and aqueducts used for municipal drinking water systems(Schrader et al. 2002). In this study, several algicides were evaluated using a rapid bioassay to determine their effectiveness in controlling the MIB-producing cyanobacterium Oscillatoria perornata from a west Mississippi catfish pond and the MIBproducing Pseudanabaena sp. (strain LW397) from Lake Whitehurst, Virginia, used as a city water supply reservoir. The cyanobacterium Oscillatoria agardhii , not a MIB-producer, and the green alga Selenastrum capricornutum , found in catfish ponds in the southeastern United States, were included in the bioassay to help determine potential broad-spectrum toxicity of the commercial products. (PDF has 3 pages.)

Evaluation of biochemical characteristics of a traditional salt fermented fish product of northeast India with special reference to its flavour components

'Lona ilish', is a traditional salt fermented fish product, widely consumed and very popular in north-east part of India and Bangladesh. It is prepared exclusively from a high fat fish, Hilsa (Tenualosa) ilisha. 'Lona ilish' was prepared in the laboratory following traditional process. After 150 days of fermentation, a better quality 'lona ilish' was obtained. Biochemical characteristics of market sample was estimated and compared with the laboratory prepared one. A variation in biochemical composition was observed. Sensory quality of the final product of laboratory prepared 'lona ilish' was compared with the market sample and found that the laboratory prepared product scored better than the market sample. The moisture (49.89%) and salt (15.48%) of the final product was found to be satisfactory for stability of the 'lona ilish' at ambient temperature. Analysis of volatile compounds of 'lona ilish' was done using GC-MS. It was concluded that, aldehydes, ketones and esters may possibly contribute characteristic aromas to the overall flavour of the salt fermented hilsa.

Methods of sensory evaluation of quality and application of statistical methods in sensory evaluation problems with special reference to fishery products

The quality of raw and processed fishery products depend on several factors like physiological conditions at the time of capture, morphological differences, rigor mortis, species, rate of icing and subsequent storage conditions. Sensory evaluation is still the most reliable method for evaluation of the freshness of raw processed fishery products. Sophisticated methods like Intelectron fish tester, cell fragility technique and chemical and bacteriological methods like estimation of trimethylamine, hypoxanthine, carbonyl compounds, volatile acid and total bacterial count have no doubt been developed for accessing the spoilage in fish products.