A Study on the quality of Persian Sturgeon (Acipenser persicus( pressed caviar in tube packaging

The Persian sturgeon (Acipenser persicus) is a species of fish in the family Acipenseridae. It is found in the Caspian Sea. Globally, sturgeon fisheries are of great economical value, primarily as a source for caviar, but also for the flesh, and several species of sturgeon are harvested for their roes. Caviar is composed of different types including pressed caviar. It is composed of damaged or fragile eggs and can be a combination of several different roes. Besides wild species, in some countries such as Iran sturgeons are sustainably farmed to produce caviar. In the present study, farmed Persian sturgeon packing pressed caviar was evaluated by tube packaging through assessing its quality and shelf life under cold storage. An unpublished report on pressed caviar packaging in tubes was not found in other countries, but in Iran, the present study is the only study performed on pressed caviar packaging in tubes.

Four treatments were considered including caviar packed in laminated tubes with an aluminum coating (Treatment 1), without coating (Treatment 2), metal tubes of aluminum type (Treatment 3), and metal cans made of stainless steel sheets (Treatment 4 and control). Treatments were packed in the amount of 50 g and stored at - 3 ° C for 7 months. Microbiological tests include the total bacterial counts, Staphylococcus bacteria, Clostridium, coliform, Escherichia coli, Psychrophilic and mold and yeast, chemical tests such as peroxide, thiobarbituric acid, free fatty acid, and total volatile nitrogen bases, physical (pH), and sensory tests including texture, odor, color, taste, salinity, and overall acceptance were performed to evaluate the quality of experimental and control treatments.

Psychrophilic, yeasts and molds, Clostridium, Coliform, and Escherichia coli were not observed in experimental and control samples. Total bacterial counts, Staphylococcus, peroxide value and physical properties (e.g. pH) were in acceptable limits in both experimental and control samples. Protein, fat, moisture, ash, and pH were %29.81, 18.00, 48.96, 3.24, and 6.98 – 7.42 in these samples. TVB-N and pH showed significant differences in treatments 3 and 4 as compared with the other treatments which were higher than the standard level. Sensory properties and overall acceptance (1.14) and free fatty acids (3.17 %) were significantly different in treatment 3 as compared with the other treatments and control (4.47 and 2.15 %) (it was not in the allowable range). Changes of pH (6.98), peroxide (0.76 meq/kg oil), TVB-N (17.64 mg/100g), free fatty acids (2.13%), total bacterial counts and Staphylococcus (1.85 and 1.11 logCFU/g), and overall acceptance (4.70) were better in treatment 2. The quality superiority of these samples was confirmed. Treatments 3 and 4 for six months, while other experimental treatments were of good quality until the end of the storage period in the cold room.

Since the chemical, microbial and sensory quality in treatment 2 was better than other treatments, so aluminum-coated laminate tubes recommended for packing of pressed caviar.