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Ultra-high Temperature (ultra-high + temperature)
Selected AbstractsEffect of somatic cell counts on lipolysis, proteolysis and apparent viscosity of UHT milk during storageINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 4 2008ANDREZZA M FERNANDES In this work, lipolysis, proteolysis and viscosity of ultra-high temperature (UHT) milk containing different somatic cell counts (SCC) were investigated. UHT milks were analysed on days 8, 30, 60, 90 and 120 of storage. Lipolysis as measured by free fatty acids increase, casein degradation and viscosity of UHT milk were not affected by SCC but increased during storage. A negative relationship was observed between SCC and casein as a percentage of true protein on the 120th day of storage, hence indicating that high SCC increases the proteolysis of UHT milk by the end of its shelf life. [source] Effect of Ultra-high Temperature Treatment on the Enzymatic Cross-linking of Micellar Casein and Sodium Caseinate by TransglutaminaseJOURNAL OF FOOD SCIENCE, Issue 8 2004M.P. Bönisch ABSTRACT: It was found that ultra-high temperature (UHT) treatment of sodium caseinate and native whey protein-depleted micellar casein drastically increases the protein polymerization effect of an enzymatic treatment by microbial transglutaminase (TG). As a result the concentration of the isopeptide ,-(,-glutamyl)lysine was increased significantly in UHT-treated micellar casein solutions after TG incubation compared with the unheated casein solution. Sodium caseinate was more susceptible to the cross-linking reaction as compared with the native casein micelles. The results demonstrate that the protein structure significantly affects the TG cross-linking reaction. The effect of an UHT treatment was considered to be related to a better TG accessibility due to a more open casein micelle structure and to the inactivation of a TG inhibitor substance. The results demonstrate that an unidentified component in the natural milk serum inhibits the TG reaction. The thermal inactivation of a TG inhibitor is the dominant effect explaining the improved cross-linking of UHT-treated casein micelles as well as sodium caseinate. [source] Comparison of Texture of Yogurt Made from Conventionally Treated Milk and UHT Milk Fortified with Low-heat Skim Milk PowderJOURNAL OF FOOD SCIENCE, Issue 6 2004W. Krasaekoopt ABSTRACT: The textures of yogurt made from ultra-high temperature (UHT) treated and conventionally treated milks at high total solids were investigated. The yogurt premixes, fortified with low-heat skim milk powder to 16%, 18%, and 20% total solids, were UHT processed at 143°C for 6 s and heated at 85°C for 30 min using the conventional method. The onset of gelation was delayed in the UHT-processed milk compared with conventionally heated milk. During fermentation, the viscosity of yogurt made from UHT-treated milk at 20% total solids was close to that of yogurt made from conventionally treated milk with 16% total solids. However, after storage for , 1 d, the yogurt made from UHT-treated milk had lower viscosity and gel strength than the yogurt made from conventionally treated milk. The solids level had no influence on yogurt culture growth. [source] Inactivation of Campylobacter jejuni by high hydrostatic pressureLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2004E.B. Solomon Abstract Aims:, To investigate the response of Campylobacter jejuni ATCC 35919 and 35921 to high pressure processing (HPP) while suspended in microbiological media and various food systems. Methods and Results:,Campylobacter jejuni 35919 and 35921 were subjected to 10-min pressure treatments between 100 and 400 MPa at 25°C suspended in Bolton broth, phosphate buffer (0·2 m, pH 7·3), ultra-high temperature (UHT) whole milk, UHT skim milk, soya milk and chicken pureé. The survivability of C. jejuni was further investigated by inoculated pack studies. HPP at 300,325 MPa for 10 min at 25°C was sufficient to reduce viable numbers of both strains to below detectable levels when cells were pressurized in Bolton broth or phosphate buffer. All food products examined offered a protective effect in that an additional 50,75 MPa was required to achieve similar levels of inactivation when compared with broth and buffer. Inoculated pack studies showed that the survivability of C. jejuni following pressurization improved with decreasing post-treatment storage temperature. Significance and Impact of the Study:, These data demonstrated that HPP at levels of ,400 MPa, can inactivate C. jejuni in both model and food systems. [source] Stability and activity of specific antibodies against Streptococcus mutans and Streptococcus sobrinus in bovine milk fermented with Lactobacillus rhamnosus strain GG or treated at ultra-high temperatureMOLECULAR ORAL MICROBIOLOGY, Issue 1 2002H. Wei Passive local immunization against dental caries is a promising approach to its prevention, as clinical evidence of active oral or nasal immunization is still limited and controversial. By means of systemic immunization of pregnant cows with a multivalent vaccine, high titres of IgG antibodies against human cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus, were produced in bovine colostrum. The purified immune product (IP) of this preparation has a number of anticariogenic properties, such as inhibition of streptococcal adherence to saliva-coated hydroxyapatite and inhibition of glucosyltransferase enzymes. This study investigated whether IP antibodies remained active and functional when added to ultra-high temperature (UHT)-treated milk or to Lactobacillus rhamnosus GG (LGG)-fermented milk stored for an extended time. LGG was chosen because of its widely known health benefits in humans and animals. A commercial UHT toddler's milk was supplemented with IP and stored for 2 months at 5, 21 and 30°C. The antistreptococcal titres in UHT milk did not decline at any temperature during storage, and UHT-IP inhibited the adherence of S. mutans for up to 2 months. This was not the case with UHT toddler's milk without IgG antibodies. Milk was fermented with live LGG cells in the presence or absence of 5% IP. The antistrept?ococcal titres declined to about 30% of the original titres after storage. Fresh milk alone slightly enhanced streptococcal adhesion but fresh milk with IP inhibited the adherence of S. mutans by over 50%. LGG-positive fermented milk without antibodies also inhibited (P < 0.05) the adhesion by about 40%. In both LGG-fermented and UHT immune milk, the activity of antibodies against cariogenic streptococci was maintained during the expected shelf-life of these products. From the anticariogenic point of view it may be beneficial to add bovine-specific antibodies against mutans streptococci to probiotic LGG-containing milk products. [source] | ||||||||||