ABSTRACT
Effects of vacuum packaging and frozen storage were studied on the formation of free fatty acids (FFAs), volatile compounds and microbial counts of Motal cheese samples stored for a period of 180 days. The FFA concentration of Motal cheese samples increased throughout the storage period of 180 days. However, the FFA contents of samples stored at -18 °C showed considerably lower values than those of the samples stored at 4 °C. Palmitic (C16:0) and oleic (C18:1) acids were the most abundant FFAs in all the treatments. The volatile compounds detected by headspace solid-phase microextraction (HS-SPME) profile of Motal cheese consisted of 16 esters, 10 acids, 6 ketones, 4 alcohols, 3 aldehydes, styrene, p-cresol and m-cresol. Results showed that storage at -18 °C can limit the excessive volatile compound formation. Samples stored at 4°C with vacuum packaging showed comparatively high concentration of esters, ketones and alcohols. Samples stored without vacuum packaging at 4°C showed 2-nonanone as the most abundant volatile compound toward the end of storage period. Storage at 4°C under vacuum packaging decreased the mold-yeast counts of samples. Frozen storage could be a suitable method for storing the Motal cheese.
Subject(s)
Cheese/analysis , Fatty Acids, Nonesterified/analysis , Food Handling , Food Packaging , Frozen Foods/analysis , Animals , Cattle , Cheese/microbiology , Cold Temperature/adverse effects , Colony Count, Microbial , Food Preservation/methods , Frozen Foods/microbiology , Fungi/growth & development , Ketones/analysis , Microbial Viability , Principal Component Analysis , Refrigeration , Sheep, Domestic , Time Factors , Turkey , Vacuum , Volatile Organic Compounds/analysisABSTRACT
The effects of packaging methods (nonvacuum and vacuum) on biogenic amines (cadaverine, putrescine, tyramine, tryptamine, phenylethylamine, and histamine) and organic acids (citric, lactic, formic, acetic, propionic, and butyric) during storage for 180 d at 4°C were investigated in Kashar cheese. Dry matter, titratable acidity, total nitrogen, water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, phosphotungstic acid-soluble nitrogen, free amino group (proteolysis), pH, fat, and acid degree value were also determined. Storage period had a significant effect on all of the biogenic amines. When compared with vacuum packaging, nonvacuum packaging resulted in no large differences among the amounts of biogenic amines. Vacuum-packaged cheeses had more lactic, formic, acetic, and butyric acids than did cheeses packaged without vacuum. Water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, phosphotungstic acid-soluble nitrogen, proteolysis, pH, and acid degree values of the cheese samples increased continuously until the end of the ripening in all the samples. No significant change was observed in total nitrogen, dry matter, or fat content within the ripening period, whereas titratable acidity values changed significantly in vacuum-packaged cheese and decreased slightly in the non-vacuum-packaged cheeses. The results of this study showed that storage period and packaging method had significant effects on the quality of Kashar cheese.
Subject(s)
Biogenic Amines/analysis , Carboxylic Acids/analysis , Cheese/analysis , Food Packaging/methods , Food Preservation , Time Factors , VacuumABSTRACT
The effects of storage temperature (+4 degrees C and -18 degrees C) and packaging method (nonvacuum and vacuum) on biogenic amines in Motal cheese during storage periods were investigated. In addition, dry matter, titratable acidity, total nitrogen, water-soluble nitrogen, trichloroacetic acid-soluble nitrogen, phosphotungstic acid-soluble nitrogen, free amino group (proteolysis), electrophoretic patterns of casein, and amounts of lactic acid bacteria and coliforms were determined. Storage period had a significant effect on all of the biogenic amines. When compared with vacuum packaging, normal packaging had higher amounts of putrescine, cadaverine, histamine, and tyramine. Coliforms were not found at detectable levels (<100cfu/g) in all cheese samples. Results of urea-PAGE analysis of cheese samples were in good agreement with biogenic amine results and other proteolysis parameters.
Subject(s)
Cheese/standards , Food Handling/methods , Biogenic Amines/analysis , Cheese/analysis , Cheese/microbiology , Food Packaging/methods , TemperatureABSTRACT
We aimed to investigate changes in serum concentrations of the cytokines interleukin (IL)-2 and interferon (IFN)-gamma during the clinical course of active tuberculosis, to establish the presence of cellular immunity before and after treatment. Blood samples were taken from 18 patients with active tuberculosis before and 2 months after therapy; IL-2 and IFN-gamma concentrations were evaluated. The mean serum IL-2 concentration before therapy was 164.5 pg/ml (range 12-980 pg/ml) and the concentration 2 months after therapy was 92.11 pg/ml (range 1-490 pg/ml). The mean serum IFN-gamma concentrations were 10.83 pg/ml (range 1-22.2 pg/ml) and 4.64 pg/ml (range 1-28.5 pg/ml), respectively. The decrease in concentrations of both cytokines after therapy was statistically significant. Further studies investigating the benefits of adding cytokines to drug treatment for tuberculosis are needed.
