Effect of Gamma Irradiation on the Sensory Quality and Amino Acid Yield of Antarctic Krill De-oiled by Supercritical CO2

Abstract

Research has demonstrated the advantages of radiation treatment in preserving and enhancing the microbial quality of seafood. Additionally, previous studies have illustrated the sensitivity of amino acids to radiation. Consequently, our study aimed to examine the impacts of gamma irradiation on the nutritional, bacteriological, and sensory state of krill. Applied doses consisted of 0 (control), 1, 5, and 10 KGy. Processed samples were initially de-oiled using supercritical CO2 to enhance the efficacy of hydrolysis through sub-critical water. The experiment was conducted within a temperature series of 200 to 280°C, with a material-to-water ratio of 1:50 for hydrolysis, and for less than 5 minutes of reaction time to minimize amino acid decomposition. The study examined the sensory and bacteriological quality of irradiation-treated krill compared to untreated samples. The hydrolysate of all treated samples yielded the highest amount of amino acids at 280ºC. The total concentration of amino acids was similar in both treated and untreated samples. Sensory evaluation showed no differences among all samples directly after irradiation. After 50 days of storage at 5°C, the sensory quality of irradiated krill was satisfactory; nevertheless, the quality of untreated krill deteriorated. The thiobarbituric acid values remained unchanged, regardless of the dose of irradiation and duration of storage.