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Todor Vasiljevic - One of the best experts on this subject based on the ideXlab platform.
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Predicting sediment formation in ultra high temperature-treated whole and skim milk using attenuated total reflectance-Fourier transform infrared spectroscopy
International Dairy Journal, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Establishing Accelerated Shelf-Life testing using Fourier transform infrared spectroscopy (FTIR) as a tool for prediction of stability requires pre-assessment of correlations between spectral changes and instability development during storage at room temperature. Comparison of results with those at elevated temperatures would establish appropriateness of Accelerated Shelf-Life testing. UHT skim milk (SM) and UHT whole milk (WM) were stored at 20 °C for 9 months to investigate the feasibility of identifying spectral markers to predict sedimentation (a measure of instability). Marker variables corresponding to changes in structure and interactions of lipids, proteins and carbohydrates successfully predicted sedimentation in SM (R2 = 0.92) and WM (R2 = 0.60). Low predictability in WM may be due to influence of fat. These markers were similar to those observed during Accelerated Shelf-Life testing, hence affirming its application with further work required to develop a model able to forecast sedimentation and other instabilities in UHT milk.
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Predicting sediment formation in ultra high temperature-treated whole and skim milk using attenuated total reflectance-Fourier transform infrared spectroscopy
International Dairy Journal, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Establishing Accelerated Shelf-Life testing using Fourier transform infrared spectroscopy (FTIR) as a tool for prediction of stability requires pre-assessment of correlations between spectral changes and instability development during storage at room temperature. Comparison of results with those at elevated temperatures would establish appropriateness of Accelerated Shelf-Life testing. UHT skim milk (SM) and UHT whole milk (WM) were stored at 20 °C for 9 months to investigate the feasibility of identifying spectral markers to predict sedimentation (a measure of instability). Marker variables corresponding to changes in structure and interactions of lipids, proteins and carbohydrates successfully predicted sedimentation in SM (R2 = 0.92) and WM (R2 = 0.60). Low predictability in WM may be due to influence of fat. These markers were similar to those observed during Accelerated Shelf-Life testing, hence affirming its application with further work required to develop a model able to forecast sedimentation and other instabilities in UHT milk.
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electrophoretic characterization of protein interactions suggesting limited feasibility of Accelerated Shelf Life testing of ultra high temperature milk
Journal of Dairy Science, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Accelerated Shelf-Life testing is applied to a variety of products to estimate keeping quality over a short period of time. The industry has not been successful in applying this approach to ultra-high temperature (UHT) milk because of chemical and physical changes in the milk proteins that take place during processing and storage. We investigated these protein changes, applying Accelerated Shelf-Life principles to UHT milk samples with different fat levels and using native- and sodium dodecyl sulfate-PAGE. Samples of UHT skim and whole milk were stored at 20, 30, 40, and 50°C for 28 d. Irrespective of fat content, UHT treatment had a similar effect on the electrophoretic patterns of milk proteins. At the start of testing, proteins were bonded mainly through disulfide and noncovalent interactions. However, storage at and above 30°C enhanced protein aggregation via covalent interactions. The extent of aggregation appeared to be influenced by fat content; whole milk contained more fat than skim milk, implying aggregation via melted or oxidized fat, or both. Based on reduction in loss in absolute quantity of individual proteins, covalent crosslinking in whole milk was facilitated mainly by products of lipid oxidation and increased access to caseins for crosslinking reactions. Maillard and dehydroalanine products were the main contributors involved in protein changes in skim milk. Protein crosslinking appeared to follow a different pathway at higher temperatures (≥40°C) than at lower temperatures, making it very difficult to extrapolate these changes to protein interactions at lower temperatures.
Manpreet Kaur Grewal - One of the best experts on this subject based on the ideXlab platform.
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Predicting sediment formation in ultra high temperature-treated whole and skim milk using attenuated total reflectance-Fourier transform infrared spectroscopy
International Dairy Journal, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Establishing Accelerated Shelf-Life testing using Fourier transform infrared spectroscopy (FTIR) as a tool for prediction of stability requires pre-assessment of correlations between spectral changes and instability development during storage at room temperature. Comparison of results with those at elevated temperatures would establish appropriateness of Accelerated Shelf-Life testing. UHT skim milk (SM) and UHT whole milk (WM) were stored at 20 °C for 9 months to investigate the feasibility of identifying spectral markers to predict sedimentation (a measure of instability). Marker variables corresponding to changes in structure and interactions of lipids, proteins and carbohydrates successfully predicted sedimentation in SM (R2 = 0.92) and WM (R2 = 0.60). Low predictability in WM may be due to influence of fat. These markers were similar to those observed during Accelerated Shelf-Life testing, hence affirming its application with further work required to develop a model able to forecast sedimentation and other instabilities in UHT milk.
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Predicting sediment formation in ultra high temperature-treated whole and skim milk using attenuated total reflectance-Fourier transform infrared spectroscopy
International Dairy Journal, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Establishing Accelerated Shelf-Life testing using Fourier transform infrared spectroscopy (FTIR) as a tool for prediction of stability requires pre-assessment of correlations between spectral changes and instability development during storage at room temperature. Comparison of results with those at elevated temperatures would establish appropriateness of Accelerated Shelf-Life testing. UHT skim milk (SM) and UHT whole milk (WM) were stored at 20 °C for 9 months to investigate the feasibility of identifying spectral markers to predict sedimentation (a measure of instability). Marker variables corresponding to changes in structure and interactions of lipids, proteins and carbohydrates successfully predicted sedimentation in SM (R2 = 0.92) and WM (R2 = 0.60). Low predictability in WM may be due to influence of fat. These markers were similar to those observed during Accelerated Shelf-Life testing, hence affirming its application with further work required to develop a model able to forecast sedimentation and other instabilities in UHT milk.
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electrophoretic characterization of protein interactions suggesting limited feasibility of Accelerated Shelf Life testing of ultra high temperature milk
Journal of Dairy Science, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Accelerated Shelf-Life testing is applied to a variety of products to estimate keeping quality over a short period of time. The industry has not been successful in applying this approach to ultra-high temperature (UHT) milk because of chemical and physical changes in the milk proteins that take place during processing and storage. We investigated these protein changes, applying Accelerated Shelf-Life principles to UHT milk samples with different fat levels and using native- and sodium dodecyl sulfate-PAGE. Samples of UHT skim and whole milk were stored at 20, 30, 40, and 50°C for 28 d. Irrespective of fat content, UHT treatment had a similar effect on the electrophoretic patterns of milk proteins. At the start of testing, proteins were bonded mainly through disulfide and noncovalent interactions. However, storage at and above 30°C enhanced protein aggregation via covalent interactions. The extent of aggregation appeared to be influenced by fat content; whole milk contained more fat than skim milk, implying aggregation via melted or oxidized fat, or both. Based on reduction in loss in absolute quantity of individual proteins, covalent crosslinking in whole milk was facilitated mainly by products of lipid oxidation and increased access to caseins for crosslinking reactions. Maillard and dehydroalanine products were the main contributors involved in protein changes in skim milk. Protein crosslinking appeared to follow a different pathway at higher temperatures (≥40°C) than at lower temperatures, making it very difficult to extrapolate these changes to protein interactions at lower temperatures.
Petros S Taoukis - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Shelf Life of flavored dehydrated products using Accelerated Shelf Life testing and the Weibull Hazard sensory analysis
Developments in Food Science, 1998Co-Authors: M. Bili, Petros S TaoukisAbstract:The Shelf Life of foods is a function of their composition, processing, packaging and environmental factors, most notably temperature. For dehydrated foods, end of Shelf Life is usually signaled by an unacceptable loss of sensory attributes. Since the time to reach this level of unacceptability, under normal storage conditions, is targeted to be 12 to 24 months, techniques of Accelerated Shelf Life Testing (ASLT) are employed to determine the Shelf Life of such products within a reasonable length of time. Use of Weibull Hazard Analysis facilitates the effective application of ASLT with sensory evaluation by allowing the use of a practical panel size and easy quantitation of the results. These can be used to model the Shelf Life behavior and to extrapolate from Accelerated to normal conditions. The degradation of the intense sweetener aspartame was studied in a gelatin-based dessert with a fruity flavor. Tests were conducted at 45, 50 and 60°C and the end of Shelf Life, expressed as unacceptably low level of sweetness, was determined by sensory evaluation as 70.4, 51.9 and 24.3 days respectively. An activation energy of degradation of aspartame, EA, was calculated as 15.1 kcal/mol, from which a Shelf Life for the product stored at 20°C of 554 days was estimated. Sensory results correlated very well with HPLC measurements of the aspartame degradation giving practically the same EA, and showing that end of Shelf Life coincided in all cases with 60% remaining aspartame. © 1998 Elsevier B.V. All rights reserved.
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evaluation of Shelf Life of flavored dehydrated products using Accelerated Shelf Life testing and the weibull hazard sensory analysis
Developments in food science, 1998Co-Authors: M. Bili, Petros S TaoukisAbstract:Abstract The Shelf Life of foods is a function of their composition, processing, packaging and environmental factors, most notably temperature. For dehydrated foods, end of Shelf Life is usually signaled by an unacceptable loss of sensory attributes. Since the time to reach this level of unacceptability, under normal storage conditions, is targeted to be 12 to 24 months, techniques of Accelerated Shelf Life Testing (ASLT) are employed to determine the Shelf Life of such products within a reasonable length of time. Use of Weibull Hazard Analysis facilitates the effective application of ASLT with sensory evaluation by allowing the use of a practical panel size and easy quantitation of the results. These can be used to model the Shelf Life behavior and to extrapolate from Accelerated to normal conditions. The degradation of the intense sweetener aspartame was studied in a gelatin-based dessert with a fruity flavor. Tests were conducted at 45, 50 and 60°C and the end of Shelf Life, expressed as unacceptably low level of sweetness, was determined by sensory evaluation as 70.4, 51.9 and 24.3 days respectively. An activation energy of degradation of aspartame, E A , was calculated as 15.1 kcal/mol, from which a Shelf Life for the product stored at 20°C of 554 days was estimated. Sensory results correlated very well with HPLC measurements of the aspartame degradation giving practically the same E A , and showing that end of Shelf Life coincided in all cases with 60% remaining aspartame.
Vasso Apostolopoulos - One of the best experts on this subject based on the ideXlab platform.
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Predicting sediment formation in ultra high temperature-treated whole and skim milk using attenuated total reflectance-Fourier transform infrared spectroscopy
International Dairy Journal, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Establishing Accelerated Shelf-Life testing using Fourier transform infrared spectroscopy (FTIR) as a tool for prediction of stability requires pre-assessment of correlations between spectral changes and instability development during storage at room temperature. Comparison of results with those at elevated temperatures would establish appropriateness of Accelerated Shelf-Life testing. UHT skim milk (SM) and UHT whole milk (WM) were stored at 20 °C for 9 months to investigate the feasibility of identifying spectral markers to predict sedimentation (a measure of instability). Marker variables corresponding to changes in structure and interactions of lipids, proteins and carbohydrates successfully predicted sedimentation in SM (R2 = 0.92) and WM (R2 = 0.60). Low predictability in WM may be due to influence of fat. These markers were similar to those observed during Accelerated Shelf-Life testing, hence affirming its application with further work required to develop a model able to forecast sedimentation and other instabilities in UHT milk.
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Predicting sediment formation in ultra high temperature-treated whole and skim milk using attenuated total reflectance-Fourier transform infrared spectroscopy
International Dairy Journal, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Establishing Accelerated Shelf-Life testing using Fourier transform infrared spectroscopy (FTIR) as a tool for prediction of stability requires pre-assessment of correlations between spectral changes and instability development during storage at room temperature. Comparison of results with those at elevated temperatures would establish appropriateness of Accelerated Shelf-Life testing. UHT skim milk (SM) and UHT whole milk (WM) were stored at 20 °C for 9 months to investigate the feasibility of identifying spectral markers to predict sedimentation (a measure of instability). Marker variables corresponding to changes in structure and interactions of lipids, proteins and carbohydrates successfully predicted sedimentation in SM (R2 = 0.92) and WM (R2 = 0.60). Low predictability in WM may be due to influence of fat. These markers were similar to those observed during Accelerated Shelf-Life testing, hence affirming its application with further work required to develop a model able to forecast sedimentation and other instabilities in UHT milk.
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electrophoretic characterization of protein interactions suggesting limited feasibility of Accelerated Shelf Life testing of ultra high temperature milk
Journal of Dairy Science, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Accelerated Shelf-Life testing is applied to a variety of products to estimate keeping quality over a short period of time. The industry has not been successful in applying this approach to ultra-high temperature (UHT) milk because of chemical and physical changes in the milk proteins that take place during processing and storage. We investigated these protein changes, applying Accelerated Shelf-Life principles to UHT milk samples with different fat levels and using native- and sodium dodecyl sulfate-PAGE. Samples of UHT skim and whole milk were stored at 20, 30, 40, and 50°C for 28 d. Irrespective of fat content, UHT treatment had a similar effect on the electrophoretic patterns of milk proteins. At the start of testing, proteins were bonded mainly through disulfide and noncovalent interactions. However, storage at and above 30°C enhanced protein aggregation via covalent interactions. The extent of aggregation appeared to be influenced by fat content; whole milk contained more fat than skim milk, implying aggregation via melted or oxidized fat, or both. Based on reduction in loss in absolute quantity of individual proteins, covalent crosslinking in whole milk was facilitated mainly by products of lipid oxidation and increased access to caseins for crosslinking reactions. Maillard and dehydroalanine products were the main contributors involved in protein changes in skim milk. Protein crosslinking appeared to follow a different pathway at higher temperatures (≥40°C) than at lower temperatures, making it very difficult to extrapolate these changes to protein interactions at lower temperatures.
Osaana Donkor - One of the best experts on this subject based on the ideXlab platform.
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Predicting sediment formation in ultra high temperature-treated whole and skim milk using attenuated total reflectance-Fourier transform infrared spectroscopy
International Dairy Journal, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Establishing Accelerated Shelf-Life testing using Fourier transform infrared spectroscopy (FTIR) as a tool for prediction of stability requires pre-assessment of correlations between spectral changes and instability development during storage at room temperature. Comparison of results with those at elevated temperatures would establish appropriateness of Accelerated Shelf-Life testing. UHT skim milk (SM) and UHT whole milk (WM) were stored at 20 °C for 9 months to investigate the feasibility of identifying spectral markers to predict sedimentation (a measure of instability). Marker variables corresponding to changes in structure and interactions of lipids, proteins and carbohydrates successfully predicted sedimentation in SM (R2 = 0.92) and WM (R2 = 0.60). Low predictability in WM may be due to influence of fat. These markers were similar to those observed during Accelerated Shelf-Life testing, hence affirming its application with further work required to develop a model able to forecast sedimentation and other instabilities in UHT milk.
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Predicting sediment formation in ultra high temperature-treated whole and skim milk using attenuated total reflectance-Fourier transform infrared spectroscopy
International Dairy Journal, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Establishing Accelerated Shelf-Life testing using Fourier transform infrared spectroscopy (FTIR) as a tool for prediction of stability requires pre-assessment of correlations between spectral changes and instability development during storage at room temperature. Comparison of results with those at elevated temperatures would establish appropriateness of Accelerated Shelf-Life testing. UHT skim milk (SM) and UHT whole milk (WM) were stored at 20 °C for 9 months to investigate the feasibility of identifying spectral markers to predict sedimentation (a measure of instability). Marker variables corresponding to changes in structure and interactions of lipids, proteins and carbohydrates successfully predicted sedimentation in SM (R2 = 0.92) and WM (R2 = 0.60). Low predictability in WM may be due to influence of fat. These markers were similar to those observed during Accelerated Shelf-Life testing, hence affirming its application with further work required to develop a model able to forecast sedimentation and other instabilities in UHT milk.
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electrophoretic characterization of protein interactions suggesting limited feasibility of Accelerated Shelf Life testing of ultra high temperature milk
Journal of Dairy Science, 2017Co-Authors: Manpreet Kaur Grewal, Jayani Chandrapala, Osaana Donkor, Vasso Apostolopoulos, Todor VasiljevicAbstract:Accelerated Shelf-Life testing is applied to a variety of products to estimate keeping quality over a short period of time. The industry has not been successful in applying this approach to ultra-high temperature (UHT) milk because of chemical and physical changes in the milk proteins that take place during processing and storage. We investigated these protein changes, applying Accelerated Shelf-Life principles to UHT milk samples with different fat levels and using native- and sodium dodecyl sulfate-PAGE. Samples of UHT skim and whole milk were stored at 20, 30, 40, and 50°C for 28 d. Irrespective of fat content, UHT treatment had a similar effect on the electrophoretic patterns of milk proteins. At the start of testing, proteins were bonded mainly through disulfide and noncovalent interactions. However, storage at and above 30°C enhanced protein aggregation via covalent interactions. The extent of aggregation appeared to be influenced by fat content; whole milk contained more fat than skim milk, implying aggregation via melted or oxidized fat, or both. Based on reduction in loss in absolute quantity of individual proteins, covalent crosslinking in whole milk was facilitated mainly by products of lipid oxidation and increased access to caseins for crosslinking reactions. Maillard and dehydroalanine products were the main contributors involved in protein changes in skim milk. Protein crosslinking appeared to follow a different pathway at higher temperatures (≥40°C) than at lower temperatures, making it very difficult to extrapolate these changes to protein interactions at lower temperatures.
