The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Devin G Peterson - One of the best experts on this subject based on the ideXlab platform.
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control of maillard type off flavor development in ultrahigh temperature Processed bovine Milk by phenolic chemistry
Journal of Agricultural and Food Chemistry, 2014Co-Authors: Smaro Kokkinidou, Devin G PetersonAbstract:The application of phenolic compounds to suppress Maillard chemistry and off-flavor development in ultrahigh-termperature (UHT)-Processed Milk during processing and storage was investigated. Five p...
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inhibition of key aroma compound generated during ultrahigh temperature processing of bovine Milk via epicatechin addition
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Paula M Colahansederstrom, Devin G PetersonAbstract:The ability of epicatechin (EC) to inhibit the thermal development of aroma compounds (i.e., Maillard reaction products) formed during ultrahigh-temperature (UHT) processing of bovine Milk was evaluated. Volatile extracts were prepared for two UHT-Processed Milk samples made from (1) raw Milk and (2) raw Milk containing 0.1% EC by solvent-assisted flavor evaporation (SAFE) and subsequently analyzed by aroma extract dilution analysis (AEDA). Sensory evaluation was also conducted by a trained panel on the intensity of cooked flavor and bitterness in four UHT-Processed Milk samples (0.00, 0.01, 0.10, and 0.20% EC added prior to processing), as well as a commercial pasteurized Milk sample for comparison. AEDA indicated that addition of EC to raw fluid Milk prior to UHT processing reduced the overall thermal formation of key aroma-active compounds in comparison to the traditional UHT Milk sample. The largest changes in FD values were reported for methional, furfural, 2-isopropyl-3-methoxypyrazine, 2-acetyl-1-p...
Monika Pischetsrieder - One of the best experts on this subject based on the ideXlab platform.
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Modified Peptides as Indicators for Thermal and Nonthermal Reactions in Processed Milk
Journal of agricultural and food chemistry, 2014Co-Authors: Jasmin Meltretter, Johannes Wüst, Monika PischetsriederAbstract:Site-specific relative quantification of β-lactoglobulin modifications in heated Milk and dairy products was performed to determine their thermal and nonthermal origins and to evaluate marker candidates for Milk processing. Therefore, formation kinetics of 19 different structures at 26 binding sites were analyzed by ultrahigh-performance liquid chromatography–tandem mass spectrometry with multiple reaction monitoring (UHPLC-MS/MS/MRM) after specific protein hydrolysis. The results indicate that (i) site-specific analysis of lactulosyllysine may be a more sensitive marker for mild heat treatment than its overall content; (ii) Ne-carboxymethyllysine, N-terminal ketoamide, and asparagine deamidation are of thermal origin and may be good markers for rather intensive heat treatment, whereas Ne-carboxyethyllysine reflects thermal and nonthermal processes; (iii) the relevance of methylglyoxal-derived arginine modifications is low compared to that of other modifications; (iv) oxidation of methionine and cysteine ...
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Distribution of protein oxidation products in the proteome of thermally Processed Milk.
Journal of agricultural and food chemistry, 2012Co-Authors: Bianca Meyer, Florian Baum, Gregor Vollmer, Monika PischetsriederAbstract:During thermal Milk processing, severe oxidation can occur, which alters the technological and physiological properties of the Milk proteins. Due to differences in composition and physicochemical properties, it can be expected that the particular Milk proteins are differently affected by oxidative damage. Therefore, the protein-specific distribution of oxidation products in the heated Milk proteome was investigated. Raw and heated Milk samples were separated by one-dimensional gel electrophoresis. Protein oxidation was visualized by Western blot after derivatization of protein carbonyls with 2,4-dinitrophenylhydrazine. Thus, α-lactalbumin displayed enhanced oxidation compared to β-lactoglobulin, despite its lower concentration in Milk. Highly selective oxidation was detected for a previously unassigned minor Milk protein. The protein was identified by its peptide mass fingerprint as a variant of αS1-casein (αS1-casein*). Similar oxidation patterns were observed in several commercial Milk products.
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Detection of Maillard products of lactose in heated or Processed Milk by HPLC/DAD
Zeitschrift f�r Lebensmitteluntersuchung und -Forschung A, 1999Co-Authors: Monika Pischetsrieder, Ursula Groß, Christiane SchoetterAbstract:Two HPLC methods with diode array detection were used to separate Maillard products from Milk components. The Maillard products 4-(β-d-galactopyranosyloxy)-2-hydroxy-2-methyl-2H-pyran-3(6H)-one (2), 1-[3-(β-d-galactopyranosyloxy)-2-furanyl]-1-ethanone (4), 4-(β-d-galactopyranosyloxy)-5-(hydroxymethyl)-2-methyl-3(2H)-furanone (5), isomaltol (7), maltol (9), 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (6), and 5-hydroxymethyl-2-furfuraldehyde (8) were determined using a water-methanol gradient. Furthermore, 4,5-dihydroxy-2-(β-d-galactopyranosyloxy)-5-methyl-2-cyclopenten-1-one (3) was separated from the Milk components by applying the interaction reagent octylamine. Several heated or Processed Milk samples were analyzed, and formation of the Maillard products was determined and quantified. Thus it was found that 2 and 3 are early products of the Maillard reaction in Milk, whereas after prolonged heating 4, 5, and particularly 9 and 6 become more important. Compounds 7 and 8 were not detected, even if the samples were heated under stringent conditions.
Donald J. Mcmahon - One of the best experts on this subject based on the ideXlab platform.
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Microstructure of indirectly and directly heated ultra-high-temperature (UHT) Processed Milk examined using transmission electron microscopy and immunogold labelling
LWT - Food Science and Technology, 1999Co-Authors: G. W. Hillbrick, Donald J. Mcmahon, W. R. McmanusAbstract:A layer of cream (or fat) that forms on ultra-high-temperature Processed Milk during storage can make it unacceptable to the consumer. Milk homogenized after ultra-high-temperature treatment is apparently more susceptible to forming a cream layer than Milk homogenized before the heat treatment. However, this study shows that Milk homogenized after indirect ultra-high-temperature treatment has both a microstructure, as determined by transmission electron microscopy and immunogold labelling, and a cream layer thickness similar to that of Milk homogenized before indirect ultra-high-temperature treatment, suggesting that it is feasible to homogenize Milk before ultra-high-temperature treatment. Also, directly heated Milk had a microstructure similar to that of indirectly heated Milk. The locations of the caseins (κ-casein, αS1-casein and β-casein) and whey proteins (β-lactoglobulin and α-lactalbumin) were localized with the immunolabelling procedure. β-Lactoglobulin and κ-casein were found to be important proteins in forming the fat globule membrane of homogenized ultra-high-temperature Processed Milk and were localized on the fat globule membrane. The micrographs confirm that κ-casein dissociates from casein micelles on heating.
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Aseptic Rennet Coagulation of Ultra-High Temperature Processed Milk Concentrates
Journal of Dairy Science, 1996Co-Authors: Mark Smith, Donald J. McmahonAbstract:Abstract Milk was concentrated by pressure-driven filtration (UF or reverse osmosis) to 9.5, 15, 18, or 20% TS and then sterilized by UHT processing to 140°C for 4 s using plate heat exchangers. Following sterilization, samples were aseptically inoculated with rennet to coagulate the Milk, which was then stored at room temperature (22°C). We investigated the influence of TS, Milk fat, extent of heat treatment, rennet dosage, storage temperature, and storage time on gel strength and syneresis as indicators of suitability for manufacturing a shelf-stable dairy dessert. As the TS content of the UF Milk concentrate increased, gel strength also increased, and the optimum was obtained when Milk was concentrated by UF to 18% TS. A small amount of added fat increased gel strength, but an increase in fat content from 1.5 to 3.5% decreased gel strength. Gel strength and syneresis increased as the rennet dosage was increased, and the optimum was in the range of 0.005 to 0.035 RU (rennet units)/ml of Milk concentrate. Storage of the renneted UHT concentrates at 21°C yielded firmer gels and more syneresis than did storage at 4°C. Products stored for longer periods were also firmer, although syneresis increased during storage. Increasing the extent of whey protein denaturation by heating the concentrates to 81°C for 30 min before UHT processing helped reduce syneresis of the gel during storage.
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DAIRY FOODS Aseptic: Rennet Coagulation of Ultra-High Temperature Processed Milk Concentrates'
1996Co-Authors: Mark Smith, Donald J. McmahonAbstract:Milk wals concentrated by pressure-driven filtration (UF or reverse osmosis) to 9.5, 15, 18, or 20% TS and then sterilized by UHT processing to 140°C for 4 s using plate heat exchangers. Following sterilization, samples were aseptically inoculated with rennet to coagulate the Milk, which was then stored at room temperature (2 2 "C 1. We investigated the influence of TS, Milk fat, extent of heat treatment, rennet dosage, storage temperature, and storage time on gel strength and syneresis as indicators of suitability for manufacturing a shelf-stable dairy dessert. As the TS content of the UF Milk concentrate increased, gel strength also increased, and the optimum was obtained when Milk was concentrated by UF to 18% TS. A small amount of added fat increased gel strength, but an increase in fat content from 1.5 to 3.5% decreased gel strength. Gel strength and syneresis increased as the rennet dosage was increased, and the optimum was in the range of 0.005 to 0.035 RU (rennet units)/ml of Milk concentrate. Storage of the renneted 'UHT concentrates at 21°C yielded firmer gels and more syneresis than did storage at 4°C. Products stored for longer periods were also firmer, although qmeresis increased during storage. Increasing the extent of whey protein denaturation by heating the concentrates to 81°C for 30 min before UHT processing helped reduce syneresis of the gel during storage.
W. R. Mcmanus - One of the best experts on this subject based on the ideXlab platform.
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Microstructure of indirectly and directly heated ultra-high-temperature (UHT) Processed Milk examined using transmission electron microscopy and immunogold labelling
LWT - Food Science and Technology, 1999Co-Authors: G. W. Hillbrick, Donald J. Mcmahon, W. R. McmanusAbstract:A layer of cream (or fat) that forms on ultra-high-temperature Processed Milk during storage can make it unacceptable to the consumer. Milk homogenized after ultra-high-temperature treatment is apparently more susceptible to forming a cream layer than Milk homogenized before the heat treatment. However, this study shows that Milk homogenized after indirect ultra-high-temperature treatment has both a microstructure, as determined by transmission electron microscopy and immunogold labelling, and a cream layer thickness similar to that of Milk homogenized before indirect ultra-high-temperature treatment, suggesting that it is feasible to homogenize Milk before ultra-high-temperature treatment. Also, directly heated Milk had a microstructure similar to that of indirectly heated Milk. The locations of the caseins (κ-casein, αS1-casein and β-casein) and whey proteins (β-lactoglobulin and α-lactalbumin) were localized with the immunolabelling procedure. β-Lactoglobulin and κ-casein were found to be important proteins in forming the fat globule membrane of homogenized ultra-high-temperature Processed Milk and were localized on the fat globule membrane. The micrographs confirm that κ-casein dissociates from casein micelles on heating.
A R Hill - One of the best experts on this subject based on the ideXlab platform.
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rennet coagulation and cheesemaking properties of thermally Processed Milk overview and recent developments
Journal of Agricultural and Food Chemistry, 2015Co-Authors: Prashanti Kethireddipalli, A R HillAbstract:Thermally induced changes in Milk proteins and minerals, particularly interactions among caseins and denatured whey proteins, influence important properties of dairy products in both positive and negative ways. Whereas the extensive protein connectivity and increased water-holding capacity resulting from such heat-induced protein modification account for the much desired firmness of acid gels of yogurt, thermal processing, on the other hand, severely impairs clotting and adversely affects the cheesemaking properties of rennet-coagulated cheeses. In technological terms, the principal ongoing challenge in the cheese industry is to take advantage of the water-holding capacity of thermally aggregated whey proteins without compromising the rennetability of cheese Milk or the textural and functional attributes of cheese. Including some recent data from the authors’ laboratory, this paper will discuss important aspects and current literature on the use of thermally Processed Milk in the production of rennet-coag...
