Kiaulienos cheminių, fizinių ir technologinių savybių kitimas giluminio užšaldymo ir laikymo metu

Abstract

Introduction. At low temperature the preservation of foodstuffs is one of the best ways of their storage and therefore this method is widely used in meat industry. The low temperature suppresses the activity of microorganisms and tissue ferments. Therefore the meat preserved by freezing keeps for a long time its initial properties and there are only minimal changes of food value and taste. At low temperature the activity of ferments slows down but does not stop. Work object. The work object is the determination of the change of physical-chemical properties of meat during freezing and keeping in - 180 C and - 860 C temperature. Work methodics. The research as fulfilled at the laboratory of the evaluation of the cattle meat properties and the meat quality. For the rersearch taken 14 Lithuanian white pig meat samples the mean weight of which was 500 g. were taken. They were put into special freezing bags and were frozen at temperature -180 C, and -860 C. Before freezing it the physical-chemical properties of the meat were determined. Two examples from each meat samples were researched. The determination of the physical-chemical properties of the meat was fulfilled every month. Also were was taken 6 Lithuanian white pig meat samples the mean weight of which was 500 g. Before freezing it the physical-chemical properties of the meat were determined. After that was made green tea extract, 500 ml. Water ant 50 g tea. All extract was inject in to the meat samples. They were put into special freezing bags and were frozen at temperature -180 C . During the test it was researched: the cooking losses were determined by boiling the meat in the circulating water bath for 30 min. The changes of weight of the meat sample were determined by weighing the meat samples before and after boiling. The meat mildness was determined according to the Warner-Bratzler method. The meat abondance of water was determined as the diminuation of the sample weight during 24 h holding the sample hung in a special bag with the net air temperature +40 C. The water binding capacity was determined according to the Grau and Hamm method. The ash was determined by burning the organic matter of meat at temperatre 600 to 8000 C. The colour was determined according to the CIE-LAB method by measuring meat lightness (L*), colour intensity (b*) and colour tone (a*). The quantity of dry matters as determined by drying the samples to the constant mass and weighing with the automatic scales for dry matters. With the pH-meter pH was mesured. The quantity of fat was determined according to the Socslet method. Results discussion. From table Nr. 3 we see that after two month freezing dry matter was lower then not frozen meat 0.650 % (p<0.01) . After five months freezing meat drip loss was 3.87 % lower (p<0.001), comparison with two months freezing drip loss and with do not freezing 1.9 % lower (p<0.001). Not frozen meat water binding capacity after one month freezing was 8.22 (<0.001). From table Nr. 4 we see that not frozen meat drip loss after one month freezing was biggest 3.56 %(p<0.001). After five freezing months meat drip loss was lower 3.06 % (p<0.001) comparison with two months freezing drip loss. Comparison with not frozen meat drip loss after five months freezing drip loss was 0.48 % (p<0.001). After two months freezing softness comparison with one freezing month and not frozen meat softness was higher 0.67 kg/ and 1.05 kg/ (p<0.001).