Polyphenoloxidase (PPO), protease activities, melanosis and exudate loss of pre-cooked Pacific white shrimp (Litopenaeus vannamei) subjected to multiple freeze-thaw cycles (1, 3 and 5 cycles) using different thawing methods were studied. PPO and protease activities increased as freeze-thaw cycles increased (p < 0.05). Thawing using running tap water resulted in the higher increases in both PPO ...

Changes in physico-chemical properties and m enzymatic activities of some muscle proteins by freeze-thawing or freeze-drying were measured for the purpose of clarifying the mechanism of protein denaturation by freeze-thawing and freezedrying. The results showed following: Freeze-thawing unfolded the conformation of the rod-like proteins and decreased their enzymatic activities. The two effects ...

The effect of freeze-thawing on the size of egg yolk phosphatidylcholine (EggPC) vesicles in the presence of 0-40 mol% distearoylphosphatidylethanolamine-polyethylene glycol 2000 (DSPE-PEG) was studied. Mean diameters of the vesicles fell into a range of 80-150 nm after 10 times freeze-thawing in spite of their original size. In the process of freeze-thawing, two opponent events, one is fission...

The influence of the freeze-thawing process on the size and lamellarity of multilamellar PEG-lipid liposomes prepared from a mixture of egg yolk phosphatidilcholine (EggPC) and distearoyl phosphatidylethanolamine polyethyleneglycol (DSPE-PEG) 2000 was investigated. Trapped volume measurement, quasielastic light scattering (QELS) and freeze-fracture electron microscopy were used to estimate the ...

We assessed the damage to onion tissue due to freeze-thawing as the water permeability determined by using PFG-NMR and light microscopy. The water diffusion in fresh onion tissue was restricted due to cellular barriers, and the estimated water permeability was 6.99 x 10(-6)m/s. The water diffusion became considerably less restricted after freeze-thawing; the convergent value for the restricted ...

background: freezing is a common way and one of the best methods of seafood preservation for long periods of time; however, the freeze thawing process may influence the quality of food. objectives: oxidation and denaturation of proteins, sublimation and recrystallization of ice crystals can cause changes in the quality of the frozen products. this study was aimed to evaluate the effect of three...

BACKGROUND: Freezing is a common way and one of the best methods of seafood preservation for long periods of time; however, the freeze thawing process may influence the quality of food. OBJECTIVES: Oxidation and denaturation of proteins, sublimation and recrystallization of ice crystals can cause changes in the quality of the frozen products. This study was aimed to evaluate the effect of three...

OBJECTIVE We investigated the effects of freeze-thawing on the properties of articular cartilage. DESIGN The reproducibility of repeated biomechanical assay of the same osteochondral sample was first verified with 11 patellar plugs from 3 animals. Then, 4 osteochondral samples from 15 bovine patellae were divided into 4 groups. The reference samples were immersed in phosphate-buffered saline ...

BACKGROUND Mild solubilization of inclusion bodies has attracted attention in recent days, with an objective to preserve the existing native-like secondary structure of proteins, reduce protein aggregation during refolding and recovering high amount of bioactive proteins from inclusion bodies. RESULTS Here we presented an efficient method for mild solubilization of inclusion bodies by using a...

OBJECTIVE To evaluate cryodamage on human sperm motility, cryosurvival rate, and sperm chromatin assessed by acridine orange staining method (AO test) after a six-month freeze-thawing process using liquid nitrogen vapor. STUDY DESIGN Experimental study. MATERIAL AND METHOD Twenty normal semen samples were obtained from the male partner of infertile couples attending the infertility unit, Si...