ABSTRACT
The authors discuss the effects of the electrophysical (IR- and SHF-heating) and conventional methods for frying low-calorie semi-finished minced meat (chops with methyl cellulose addition) intended for treatment and prophylactic nutrition of schoolchildren on the biological value of proteins: the amino acid score, the protein qualitative index, the coefficient of the amino acid score difference, and the coefficient of the efficacy of lysine and protein availability. It has been established that the electrophysical methods of heating, especially the frying of the products by means of IR-radiation favour an improvement of a number of the parameters as compared to the conventional way of frying.
Subject(s)
Dietary Proteins/analysis , Hot Temperature , Infant Food/analysis , Meat Products/analysis , Animals , Body Weight , Energy Intake , Humans , Infant , Lysine/analysis , Meat , RatsABSTRACT
Using electrophoresis and ultracentrifugation, a homogeneous proteinase was isolated from protofradine, a protease Act. fradiae 119 preparation. The purification procedure included filtration on DEAE-cellulose, gel filtration through Arcylex P-10, CM-chromatography and desalting on Sephadex G-15. The proteinase under study is an endopeptidase which hydrolyzes low molecular weight synthetic trypsin substrates as well as casein and denaturated collagen. Diisopropylfluorophosphate and soya bean trypsin inhibitor completely inhibit the proteinase activity, whereas pCMB and EDTA have no such effect. The stability maximum is observed at pH of 2.5-3.5, the action maximum at pH 8.7-9.5. The amino acid composition of the enzyme is similar to that of trypsin from Str. griseus. The molecular weights of the proteinase as determined by gel filtration and sedimentation equilibrium method are equal to 25400 and 26500, respectively. The isoelectric point lies at 5.3. The data obtained suggest that the proteinase can be attributed to the family of trypsin proteinases.
