Extension the Shelf-Life of Fresh Golden Rainbow Trout via Ultra-Fast Air or Cryogenic Carbon Dioxide Super Chilling

Abstract

The objective of this study was to evaluate the possibilities of ultra-fast air or cryogenic super chilling by dry ice (carbon dioxide) for prolongation the shelf life of fresh golden albino of rainbow trout (Oncorhynchus mykiss), and to evaluate its effect on the fish quality comparing with flake ice chilling. The gutted fish 2 h post mortem was packed in transparent plastic polyvinyl dichloride bags with zipper. The first (control) sample was stored chilled at 0°C to 4°C. The second group was cryogenic super chilled by dry ice (CO2) at -78°C with steam flow 0.5 m/s. The third group was ultra-fast super chilled with air at -20°C with air flow 3 m/s and stored at 2°C to 3°C. All samples were examined on 0, 7th, 14th and 21st day of storage. On 21st d of storage comparison between supper chilled samples and flake ice chilled control indicated lower as follows: pH with 18.2%, TVB-N with 24.1%, FFA 9.5 times, POV about 2.5 times, TBARS and FAN approximately 2 times. The 10.40 mg cadaverine/ kg in cryogenic dry CO2 super chilled golden rainbow trout was only determined. Sensory data show a continued acceptability of fish to 14 days for super chilled (to 21st d) than in flake ice chilled (only to 7th d). Microbiological shelf life was determined as 16-18 days and 10-12 days, respectively. The conclusion was made that the ultra-fast air flow super chilling retains better sensory qualities of golden rainbow trout while super chilling with dry carbon dioxide.The objective of this study was to evaluate the possibilities of ultra-fast air or cryogenic super chilling by dry ice (carbon dioxide) for prolongation the shelf life of fresh golden albino of rainbow trout (Oncorhynchus mykiss), and to evaluate its effect on the fish quality comparing with flake ice chilling. The gutted fish 2 h post mortem was packed in transparent plastic polyvinyl dichloride bags with zipper. The first (control) sample was stored chilled at 0°C to 4°C. The second group was cryogenic super chilled by dry ice (CO2) at -78°C with steam flow 0.5 m/s. The third group was ultra-fast super chilled with air at -20°C with air flow 3 m/s and stored at 2°C to 3°C. All samples were examined on 0, 7th, 14th and 21st day of storage. On 21st d of storage comparison between supper chilled samples and flake ice chilled control indicated lower as follows: pH with 18.2%, TVB-N with 24.1%, FFA 9.5 times, POV about 2.5 times, TBARS and FAN approximately 2 times. The 10.40 mg cadaverine/ kg in cryogenic dry CO2 super chilled golden rainbow trout was only determined. Sensory data show a continued acceptability of fish to 14 days for super chilled (to 21st d) than in flake ice chilled (only to 7th d). Microbiological shelf life was determined as 16-18 days and 10-12 days, respectively. The conclusion was made that the ultra-fast air flow super chilling retains better sensory qualities of golden rainbow trout while super chilling with dry carbon dioxide.