| Popis: |
Raw cream was standardized to 10% fat and processed by ultra-high-temperature (UHT) steam injection at 149°C for 20 s, 149°C for 3.4 s, 138°C for 20 s, and 143°C for 7 s, then aseptically packaged by a Tetra Pak AB3-250 filler. Packages were stored for 12 months at 24°C and analyzed at 0, 1, 3, 6, and 12 months. Fat-soluble carbonyls were extracted from the UHT cream with carbonyl-free hexanes and converted to their 2,4-dinitrophenyl-hydrazone derivatives. Alkanal hydrazones were separated by column chromatography into pure fractions. Spectrophotometry and gas chromatography were used to identify the alkanals. Butanal, hexanal, heptanal, nonanal, and decanal were identified and found to decrease in concentration during storage. |
