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Frozen Foods Treated by Pressure Shift Freezing: Proteins and Enzymes
Author(s) -
Préstamo Guadalupe,
Palomares Lourdes,
Sanz Pedro
Publication year - 2005
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.2005.tb09059.x
Subject(s) - point of delivery , peroxidase , chemistry , molecular mass , gel electrophoresis , sodium dodecyl sulfate , enzyme , polyacrylamide gel electrophoresis , chromatography , isozyme , sodium , electrophoresis , biochemistry , food science , botany , biology , organic chemistry
This work was focused on the changes that potatoes undergo after pressure shift freezing (PSF) treatment on protein content, peroxidase (POD), and polyphenoloxidase (PPO) enzymes. The samples were subjected to different conditions of P/T (210 MPa at −20°C; 180 MPa at −16°C; 150 MPa at −12°C; and 120 MPa at −8°C). Results showed that none of these conditions were enough to inactivate the POD and PPO enzymes. The POD was more resistant than PPO. Three isoenzymes of POD (61, 51, and 46 kDa) were detected. The protein content decreased about 50% after the PSF treatment at 210 MPa, −20°C; however, sodium dodecyl sulfate‐polyacrylamide gel electrophoresis revealed 2 bands of about 21 kDa quite resistant to the treatment. On the contrary, mass spectrometry revealed among the resistant proteins, 2 fragments of pH 8.5 and about 20 kDa were more sensitive to 150 MPa, −12°C. The 2 fragments matched to a Solanum tuberosum proteinase inhibitor II protein