초임계 이산화탄소 처리가 동결 건조된 소간의 이화학적 특성 및 미생물 저감화에 미치는 영향

Abstract

Supercritical carbon dioxide (SC-CO2) treatment has been becoming an important method for substituting the use of organic solvents for samples extraction prior to analysis due to its low toxicity, ease of handling, low cost of disposal etc. Freeze-dried bovine liver was treated with SC-CO2 under different pressures (200, 300, and 450 bar) in order to investigate effects on physicochemical properties and reduction of microbial load. The yield of lipid extraction from bovine liver by SC-CO2 treatment increased with increasing pressure, with values of 84, 86, and 90% in response to 200, 300, and 450 bar, respectively. Results of high performance liquid chromatography analysis showed that vitamin A and coenzyme Q10 (CoQ10), which is soluble in lipid, were almost removed from bovine liver by SC-CO2 treatment. Saturated fatty acids ratio of bovine liver decreased with increasing pressure, whereas polyunsaturated fatty acids increased with increasing pressure. Total content of amino acids in bovine liver treated by SC-CO2 was less than that of the control sample without treatment. The number of aerobic bacteria in bovine liver, which was stored at 5°C for 5 days and freeze-dried, decreased from 6.2 to 4.2 log CFU/g by SC-CO2 treatment at 100 bar for 3 h. Interestingly, coliform bacteria were not found in the bovine liver sample by SC-CO2 at 100 bar for 3 h under all storage conditions. This indicates that SC-CO2 treatment can effectively reduce coliform bacteria in the food matrix even at low moisture. In conclusion, freeze-dried bovine liver by proper SC-CO2 treatment may be used as a potential high protein source, with increasing microbial safety and stability of lipid oxidation. ? 2015, Korean Society of Food Science and Nutrition. All rights reserved.