Publication Date:
2021-05-19
Description:
Sampling for this study was carried out at the freshwater crayfish fishing season (May to December ) from the selected packs made from one of the harvesting centers at the first day ( harvesting and packing ) until the seventh day ( the export time ) using registered number to determine the handling effect ( live ) and changes in chemical and microbial indices in tail fillet stored at -18 ° C at days 1 and every 15 days considering 1 treatment and 3 replicates. The comparison of results mean (±SE) of the effects of handling on tested indices showed a significant reduction of protein percentage (dry weight) of tail filet at day 7 (13/85 ± 0/07) comparing with fishing day (16/1 ± 0/05) ( (p 〈 0.05). So that by increasing the handling and storage period, the amount of protein (dry weight) was reduced. Comparison of carbohydrate percent (dry weight) during handling showed a significant difference between the first day (2/8 ± 0/009) with the seventh day (0/9 ± 0/005 (p 〈0.05). Percent of moisture showed a significant increase during handling between day 1 (79/2 ± 0/24) and 7 (84 ± 0.41) (p 〈 0.05). Mean chemical composition of haemolymph showed a significant reduction in triglycerides (milligrams per deciliter) at fishing day (14/3 ± 0/16) and day 7 (11/7 ± 0/13) (p 〈 0.05). Comparison the means of saturated and unsaturated fatty acid profiles and the ratio of DHA / EPA did not show significant differences (p〉0.05). Comparison of the mean (±SE) of total bacterial count (log CFU / g) and psychrophilic bacteria at different periods of tail fillet storage at - 18 °C showed significant differences at day1 ( 3.48 ± 0.00 and 1.0± 0.00) compared to day 180 ( 6.86± 0.85 and 6.75± 0.25) , respectively(p〉0.05) .Comparison of Mean (±SE) of chemical indices for first day with day 180 were thiobarbituric acid ( mg malondialdehyde /kg ) (0.19/0 ± 0/07) and (1/45 ± 0/25), peroxide ( meq oxygen/ kg fat ) (0/81 ± 0/21) and (2/2 ± 0/3), total volatile basic nitrogen ( mg per 100 g fillet ) (13/21 ± 1/01) and (26/6 ± 1 / 40) and acidity (6/26 ± 0/08) and (6/55 ± 0/05), respectively which showed significant differences with each other (p 〈 0.05). Therefore, cited to the results of microbiological and chemical parameters, maximum shelf life longetivity of freshwater crayfish tail fillets packaged in the air is recommended as 5 months after freezing at – 18 °C.
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Chemical
;
Microbial
;
Microbiological
;
Handling
;
A.leptodactylus
;
Quality
;
Freezing
;
Fillet
;
Spoilage
;
Survey
;
Fresh water
;
Crayfish
;
Astacus leptodactylus
;
Protein
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
46pp.
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