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Marena Manley - One of the best experts on this subject based on the ideXlab platform.
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enhancing aspalathin stability in rooibos aspalathus linearis ready to drink Iced Teas during storage the role of nano emulsification and beverage ingredients citric and ascorbic acids
Journal of the Science of Food and Agriculture, 2012Co-Authors: Dalene De Beer, Melvi Viljoen, Elizabeth Joubert, Marena ManleyAbstract:BACKGROUND: The effects of citric and ascorbic acids on the stability of aspalathin in rooibos (Aspalathus linearis) ready-to-drink (RTD) formulations containing fermented rooibos extract (FR), aspalathin-enriched green rooibos extract (GR) and aspalathin-enriched green rooibos extract ascorbic acid solubilisate (GR-solubilisate) were investigated during storage (12 weeks at 25 °C). RESULTS: Storage of Iced Tea formulations containing FR and GR extracts reduced their flavonoid content. The aspalathin content of FR Iced Tea without citric or ascorbic acid was reduced to undetectable levels by week 8 of storage. Addition of citric acid resulted in improved stability of aspalathin, but ascorbic acid did not impart additional stability. Iso-orientin and orientin were less affected than aspalathin, presumably owing to partial conversion of aspalathin to these flavones. Similar results were obtained for GR Iced Tea formulations. Improved stability of aspalathin was noted in Iced Tea containing GR-solubilisate with or without citric acid. Lower pH was shown to favour stability, especially for fermented rooibos Iced Teas. CONCLUSION: Citric and ascorbic acids contribute to the stability of rooibos flavonoids during storage. Differences in stability between formulations are not due to pH differences but may be related to the matrix. Copyright © 2011 Society of Chemical Industry
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use of green rooibos aspalathus linearis extract and water soluble nanomicelles of green rooibos extract encapsulated with ascorbic acid for enhanced aspalathin content in ready to drink Iced Teas
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Elizabeth Joubert, Melvi Viljoen, Dalene De Beer, Christiaan J Malherbe, Jacobus D Brand, Marena ManleyAbstract:Heat-induced changes in aspalathin, iso-orientin, and orientin content of ready-to-drink (RTD) green rooibos Iced Tea formulations were investigated. An organic-solvent-based aspalathin-enriched extract prepared from green rooibos was used "as-is" or encapsulated with ascorbic acid in a water-soluble nanomicelle-based carrier system. The common Iced Tea ingredients, ascorbic acid, and/or citric acid were added to the Iced Tea containing green rooibos extract. Only citric acid was added to the Iced Tea containing the nanomicelles. Heat treatments consisted of pasteurization (93 °C/5 min and 93 °C/30 min), normal-temperature sterilization (NTS; 121 °C/15 min), and high-temperature sterilization (HTS; 135 °C/4 min). Pasteurization had little or no effect on the flavonoid content. NTS and HTS induced significant losses in the flavonoids. The addition of citric and ascorbic acids improved the stability of the flavonoids, but encapsulation of green rooibos extract with ascorbic acid in nanomicelles did not offer additional stability. The only benefit of using the water-soluble nanomicelles was the improved clarity of the RTD product. Iso-orientin and orientin contents were substantially less affected than aspalathin by the heat treatments, partially because of conversion of aspalathin to these flavones, which countered losses. 5-Hydroxymethylfurfural (HMF), a known dehydration product of hexoses under mild acidic conditions and also a degradation product of ascorbic acid, was observed in formulations containing citric and/or ascorbic acids.
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effect of heat on aspalathin iso orientin and orientin contents and color of fermented rooibos aspalathus linearis Iced Tea
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Elizabeth Joubert, Melvi Viljoen, Dalene De Beer, Marena ManleyAbstract:The phenolic quality of commercial South African fermented rooibos Iced Teas in terms of aspalathin, iso-orientin, and orientin contents in comparison to a "cup of Tea" was shown to be inferior. The role of the different manufacturing stages of powdered extract used in Iced Tea formulation and, more specifically, the impact of pasteurization and sterilization on the color and phenolic content of the beverage, were assessed as potential causes of its inferior phenolic quality. Aspalathin and its corresponding flavones, iso-orientin and orientin, were found to be present at all stages of the powdered extract production process. Spray-drying did not significantly (P ≥ 0.05) alter the aspalathin, iso-orientin, or orientin content of concentrates. Simulated normal-temperature sterilization (NTS at 121 °C/15 min) and high-temperature sterilization (HTS at 135 °C/4 min), but not necessarily pasteurization (93 °C/30 min), significantly (P < 0.05) reduced the aspalathin, iso-orientin, and orientin contents of different Iced Tea formulations. Heat-induced losses of iso-orientin and orientin were lower than those for aspalathin. Conversion of aspalathin to the flavones is implicated. The addition of ascorbic acid and/or citric acid to the base Iced Tea formulation containing only rooibos extract and sugar proved to be beneficial, especially for the retention of aspalathin. Browning, that is, absorbance at 420 nm, was significantly (P < 0.05) increased in the base formulation. In the case of the formulations also containing ascorbic acid and/or citric acid, absorbance remained unchanged or decreased when subjected to NTS and HTS treatments. This was attributed to removal of brown polymers from solution as the pH values of these formulations were lower than that of the base formulation.
Elizabeth Joubert - One of the best experts on this subject based on the ideXlab platform.
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enhancing aspalathin stability in rooibos aspalathus linearis ready to drink Iced Teas during storage the role of nano emulsification and beverage ingredients citric and ascorbic acids
Journal of the Science of Food and Agriculture, 2012Co-Authors: Dalene De Beer, Melvi Viljoen, Elizabeth Joubert, Marena ManleyAbstract:BACKGROUND: The effects of citric and ascorbic acids on the stability of aspalathin in rooibos (Aspalathus linearis) ready-to-drink (RTD) formulations containing fermented rooibos extract (FR), aspalathin-enriched green rooibos extract (GR) and aspalathin-enriched green rooibos extract ascorbic acid solubilisate (GR-solubilisate) were investigated during storage (12 weeks at 25 °C). RESULTS: Storage of Iced Tea formulations containing FR and GR extracts reduced their flavonoid content. The aspalathin content of FR Iced Tea without citric or ascorbic acid was reduced to undetectable levels by week 8 of storage. Addition of citric acid resulted in improved stability of aspalathin, but ascorbic acid did not impart additional stability. Iso-orientin and orientin were less affected than aspalathin, presumably owing to partial conversion of aspalathin to these flavones. Similar results were obtained for GR Iced Tea formulations. Improved stability of aspalathin was noted in Iced Tea containing GR-solubilisate with or without citric acid. Lower pH was shown to favour stability, especially for fermented rooibos Iced Teas. CONCLUSION: Citric and ascorbic acids contribute to the stability of rooibos flavonoids during storage. Differences in stability between formulations are not due to pH differences but may be related to the matrix. Copyright © 2011 Society of Chemical Industry
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use of green rooibos aspalathus linearis extract and water soluble nanomicelles of green rooibos extract encapsulated with ascorbic acid for enhanced aspalathin content in ready to drink Iced Teas
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Elizabeth Joubert, Melvi Viljoen, Dalene De Beer, Christiaan J Malherbe, Jacobus D Brand, Marena ManleyAbstract:Heat-induced changes in aspalathin, iso-orientin, and orientin content of ready-to-drink (RTD) green rooibos Iced Tea formulations were investigated. An organic-solvent-based aspalathin-enriched extract prepared from green rooibos was used "as-is" or encapsulated with ascorbic acid in a water-soluble nanomicelle-based carrier system. The common Iced Tea ingredients, ascorbic acid, and/or citric acid were added to the Iced Tea containing green rooibos extract. Only citric acid was added to the Iced Tea containing the nanomicelles. Heat treatments consisted of pasteurization (93 °C/5 min and 93 °C/30 min), normal-temperature sterilization (NTS; 121 °C/15 min), and high-temperature sterilization (HTS; 135 °C/4 min). Pasteurization had little or no effect on the flavonoid content. NTS and HTS induced significant losses in the flavonoids. The addition of citric and ascorbic acids improved the stability of the flavonoids, but encapsulation of green rooibos extract with ascorbic acid in nanomicelles did not offer additional stability. The only benefit of using the water-soluble nanomicelles was the improved clarity of the RTD product. Iso-orientin and orientin contents were substantially less affected than aspalathin by the heat treatments, partially because of conversion of aspalathin to these flavones, which countered losses. 5-Hydroxymethylfurfural (HMF), a known dehydration product of hexoses under mild acidic conditions and also a degradation product of ascorbic acid, was observed in formulations containing citric and/or ascorbic acids.
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effect of heat on aspalathin iso orientin and orientin contents and color of fermented rooibos aspalathus linearis Iced Tea
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Elizabeth Joubert, Melvi Viljoen, Dalene De Beer, Marena ManleyAbstract:The phenolic quality of commercial South African fermented rooibos Iced Teas in terms of aspalathin, iso-orientin, and orientin contents in comparison to a "cup of Tea" was shown to be inferior. The role of the different manufacturing stages of powdered extract used in Iced Tea formulation and, more specifically, the impact of pasteurization and sterilization on the color and phenolic content of the beverage, were assessed as potential causes of its inferior phenolic quality. Aspalathin and its corresponding flavones, iso-orientin and orientin, were found to be present at all stages of the powdered extract production process. Spray-drying did not significantly (P ≥ 0.05) alter the aspalathin, iso-orientin, or orientin content of concentrates. Simulated normal-temperature sterilization (NTS at 121 °C/15 min) and high-temperature sterilization (HTS at 135 °C/4 min), but not necessarily pasteurization (93 °C/30 min), significantly (P < 0.05) reduced the aspalathin, iso-orientin, and orientin contents of different Iced Tea formulations. Heat-induced losses of iso-orientin and orientin were lower than those for aspalathin. Conversion of aspalathin to the flavones is implicated. The addition of ascorbic acid and/or citric acid to the base Iced Tea formulation containing only rooibos extract and sugar proved to be beneficial, especially for the retention of aspalathin. Browning, that is, absorbance at 420 nm, was significantly (P < 0.05) increased in the base formulation. In the case of the formulations also containing ascorbic acid and/or citric acid, absorbance remained unchanged or decreased when subjected to NTS and HTS treatments. This was attributed to removal of brown polymers from solution as the pH values of these formulations were lower than that of the base formulation.
Dalene De Beer - One of the best experts on this subject based on the ideXlab platform.
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enhancing aspalathin stability in rooibos aspalathus linearis ready to drink Iced Teas during storage the role of nano emulsification and beverage ingredients citric and ascorbic acids
Journal of the Science of Food and Agriculture, 2012Co-Authors: Dalene De Beer, Melvi Viljoen, Elizabeth Joubert, Marena ManleyAbstract:BACKGROUND: The effects of citric and ascorbic acids on the stability of aspalathin in rooibos (Aspalathus linearis) ready-to-drink (RTD) formulations containing fermented rooibos extract (FR), aspalathin-enriched green rooibos extract (GR) and aspalathin-enriched green rooibos extract ascorbic acid solubilisate (GR-solubilisate) were investigated during storage (12 weeks at 25 °C). RESULTS: Storage of Iced Tea formulations containing FR and GR extracts reduced their flavonoid content. The aspalathin content of FR Iced Tea without citric or ascorbic acid was reduced to undetectable levels by week 8 of storage. Addition of citric acid resulted in improved stability of aspalathin, but ascorbic acid did not impart additional stability. Iso-orientin and orientin were less affected than aspalathin, presumably owing to partial conversion of aspalathin to these flavones. Similar results were obtained for GR Iced Tea formulations. Improved stability of aspalathin was noted in Iced Tea containing GR-solubilisate with or without citric acid. Lower pH was shown to favour stability, especially for fermented rooibos Iced Teas. CONCLUSION: Citric and ascorbic acids contribute to the stability of rooibos flavonoids during storage. Differences in stability between formulations are not due to pH differences but may be related to the matrix. Copyright © 2011 Society of Chemical Industry
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use of green rooibos aspalathus linearis extract and water soluble nanomicelles of green rooibos extract encapsulated with ascorbic acid for enhanced aspalathin content in ready to drink Iced Teas
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Elizabeth Joubert, Melvi Viljoen, Dalene De Beer, Christiaan J Malherbe, Jacobus D Brand, Marena ManleyAbstract:Heat-induced changes in aspalathin, iso-orientin, and orientin content of ready-to-drink (RTD) green rooibos Iced Tea formulations were investigated. An organic-solvent-based aspalathin-enriched extract prepared from green rooibos was used "as-is" or encapsulated with ascorbic acid in a water-soluble nanomicelle-based carrier system. The common Iced Tea ingredients, ascorbic acid, and/or citric acid were added to the Iced Tea containing green rooibos extract. Only citric acid was added to the Iced Tea containing the nanomicelles. Heat treatments consisted of pasteurization (93 °C/5 min and 93 °C/30 min), normal-temperature sterilization (NTS; 121 °C/15 min), and high-temperature sterilization (HTS; 135 °C/4 min). Pasteurization had little or no effect on the flavonoid content. NTS and HTS induced significant losses in the flavonoids. The addition of citric and ascorbic acids improved the stability of the flavonoids, but encapsulation of green rooibos extract with ascorbic acid in nanomicelles did not offer additional stability. The only benefit of using the water-soluble nanomicelles was the improved clarity of the RTD product. Iso-orientin and orientin contents were substantially less affected than aspalathin by the heat treatments, partially because of conversion of aspalathin to these flavones, which countered losses. 5-Hydroxymethylfurfural (HMF), a known dehydration product of hexoses under mild acidic conditions and also a degradation product of ascorbic acid, was observed in formulations containing citric and/or ascorbic acids.
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effect of heat on aspalathin iso orientin and orientin contents and color of fermented rooibos aspalathus linearis Iced Tea
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Elizabeth Joubert, Melvi Viljoen, Dalene De Beer, Marena ManleyAbstract:The phenolic quality of commercial South African fermented rooibos Iced Teas in terms of aspalathin, iso-orientin, and orientin contents in comparison to a "cup of Tea" was shown to be inferior. The role of the different manufacturing stages of powdered extract used in Iced Tea formulation and, more specifically, the impact of pasteurization and sterilization on the color and phenolic content of the beverage, were assessed as potential causes of its inferior phenolic quality. Aspalathin and its corresponding flavones, iso-orientin and orientin, were found to be present at all stages of the powdered extract production process. Spray-drying did not significantly (P ≥ 0.05) alter the aspalathin, iso-orientin, or orientin content of concentrates. Simulated normal-temperature sterilization (NTS at 121 °C/15 min) and high-temperature sterilization (HTS at 135 °C/4 min), but not necessarily pasteurization (93 °C/30 min), significantly (P < 0.05) reduced the aspalathin, iso-orientin, and orientin contents of different Iced Tea formulations. Heat-induced losses of iso-orientin and orientin were lower than those for aspalathin. Conversion of aspalathin to the flavones is implicated. The addition of ascorbic acid and/or citric acid to the base Iced Tea formulation containing only rooibos extract and sugar proved to be beneficial, especially for the retention of aspalathin. Browning, that is, absorbance at 420 nm, was significantly (P < 0.05) increased in the base formulation. In the case of the formulations also containing ascorbic acid and/or citric acid, absorbance remained unchanged or decreased when subjected to NTS and HTS treatments. This was attributed to removal of brown polymers from solution as the pH values of these formulations were lower than that of the base formulation.
Herbert L. Meiselman - One of the best experts on this subject based on the ideXlab platform.
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the effects of contextual variables on food acceptability a confirmatory study
Food Quality and Preference, 2007Co-Authors: Silvia C King, Annette W Hottenstein, Herbert L. Meiselman, Therese M Work, Valerie CronkAbstract:Abstract Consumer acceptance of food and beverage was measured in three different settings/locations: a central location test in a laboratory facility, a central location test at one unit of a national chain restaurant and a customer satisfaction survey at the same chain restaurant in multiple cities. Two main dishes (lasagna, cannelloni), salad, breadsticks and Iced Tea were served either as individual items or as part of a meal. Meal context and the consumer’s ability to choose had the strongest positive effects on acceptance ratings, while social interaction and enhanced environment had no noticeable effects on the acceptability scores. There were significant age and gender effects in the two restaurant settings, but not in the laboratory central location test. The results of this study confirm some of the results of King et al. (2004) [King, S., Weber, A., Meiselman H., & Lv, N. (2004). The effect of meal situation, social interaction, physical environment and choice on food acceptability. Food Quality and Preference, 15, 645–653] on the enhancing effects of context variables on product acceptance, and on how the relationship between context effect and consumer acceptance may not be consistent within and across meal components.
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the effect of meal situation social interaction physical environment and choice on food acceptability
Food Quality and Preference, 2004Co-Authors: Silvia C King, Annette J Weber, Herbert L. Meiselman, Nan LvAbstract:Abstract Consumer acceptance of food and beverage was measured after modifying four key factors or `context effects' in five consumer central location tests: its function as a meal component, social interaction during consumption, the physical environment in which the food is selected and consumed, and food choice. One of two flavor variations each of salad, pizza and Iced Tea were served. Acceptance ratings and self-reported food intake were obtained from consumers. In Tests 1–5, context effects were added sequentially, so that by Test 5 all context effects were present. Sixth test served as a comparison to `real life' and took place at a local restaurant. Our hypothesis was that product acceptability would increase with the addition of the various context effects. Meal context had the strongest positive effect on Tea; social context had a strong negative effect on pizza; environment had a weak but positive effect on pizza and Tea and a negative effect on salad; and choice had a positive effect on salad. These results suggest that context variables do affect product acceptance, but that the relationship between context effect and consumer acceptance may not be consistent within and across meal components.
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effects of social interaction physical environment and food choice freedom on consumption in a meal testing environment
Appetite, 2004Co-Authors: Annette J Weber, Silvia C King, Herbert L. MeiselmanAbstract:Abstract Consumption of pizza, salad and Iced Tea was assessed in four separate tests at a central location. Three aspects of context were added in successive tests—social interaction during consumption, the physical environment in which the food was consumed and choice among foods—so that the fourth test had all effects present. The proportion consumed averaged from 79 to 82% of the food presented and increased significantly in the presence of one or more of the context manipulations. Salad consumption was higher when there was a choice of dressings in an enhanced environment. Pizza and Tea consumption were higher in an enhanced restaurant-like environment. Social interaction alone has no detectable impact on food consumption. It is concluded that people eat more in enhanced contexts and careful consideration should be given to the environment in studies of food consumption.
Melvi Viljoen - One of the best experts on this subject based on the ideXlab platform.
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enhancing aspalathin stability in rooibos aspalathus linearis ready to drink Iced Teas during storage the role of nano emulsification and beverage ingredients citric and ascorbic acids
Journal of the Science of Food and Agriculture, 2012Co-Authors: Dalene De Beer, Melvi Viljoen, Elizabeth Joubert, Marena ManleyAbstract:BACKGROUND: The effects of citric and ascorbic acids on the stability of aspalathin in rooibos (Aspalathus linearis) ready-to-drink (RTD) formulations containing fermented rooibos extract (FR), aspalathin-enriched green rooibos extract (GR) and aspalathin-enriched green rooibos extract ascorbic acid solubilisate (GR-solubilisate) were investigated during storage (12 weeks at 25 °C). RESULTS: Storage of Iced Tea formulations containing FR and GR extracts reduced their flavonoid content. The aspalathin content of FR Iced Tea without citric or ascorbic acid was reduced to undetectable levels by week 8 of storage. Addition of citric acid resulted in improved stability of aspalathin, but ascorbic acid did not impart additional stability. Iso-orientin and orientin were less affected than aspalathin, presumably owing to partial conversion of aspalathin to these flavones. Similar results were obtained for GR Iced Tea formulations. Improved stability of aspalathin was noted in Iced Tea containing GR-solubilisate with or without citric acid. Lower pH was shown to favour stability, especially for fermented rooibos Iced Teas. CONCLUSION: Citric and ascorbic acids contribute to the stability of rooibos flavonoids during storage. Differences in stability between formulations are not due to pH differences but may be related to the matrix. Copyright © 2011 Society of Chemical Industry
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use of green rooibos aspalathus linearis extract and water soluble nanomicelles of green rooibos extract encapsulated with ascorbic acid for enhanced aspalathin content in ready to drink Iced Teas
Journal of Agricultural and Food Chemistry, 2010Co-Authors: Elizabeth Joubert, Melvi Viljoen, Dalene De Beer, Christiaan J Malherbe, Jacobus D Brand, Marena ManleyAbstract:Heat-induced changes in aspalathin, iso-orientin, and orientin content of ready-to-drink (RTD) green rooibos Iced Tea formulations were investigated. An organic-solvent-based aspalathin-enriched extract prepared from green rooibos was used "as-is" or encapsulated with ascorbic acid in a water-soluble nanomicelle-based carrier system. The common Iced Tea ingredients, ascorbic acid, and/or citric acid were added to the Iced Tea containing green rooibos extract. Only citric acid was added to the Iced Tea containing the nanomicelles. Heat treatments consisted of pasteurization (93 °C/5 min and 93 °C/30 min), normal-temperature sterilization (NTS; 121 °C/15 min), and high-temperature sterilization (HTS; 135 °C/4 min). Pasteurization had little or no effect on the flavonoid content. NTS and HTS induced significant losses in the flavonoids. The addition of citric and ascorbic acids improved the stability of the flavonoids, but encapsulation of green rooibos extract with ascorbic acid in nanomicelles did not offer additional stability. The only benefit of using the water-soluble nanomicelles was the improved clarity of the RTD product. Iso-orientin and orientin contents were substantially less affected than aspalathin by the heat treatments, partially because of conversion of aspalathin to these flavones, which countered losses. 5-Hydroxymethylfurfural (HMF), a known dehydration product of hexoses under mild acidic conditions and also a degradation product of ascorbic acid, was observed in formulations containing citric and/or ascorbic acids.
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effect of heat on aspalathin iso orientin and orientin contents and color of fermented rooibos aspalathus linearis Iced Tea
Journal of Agricultural and Food Chemistry, 2009Co-Authors: Elizabeth Joubert, Melvi Viljoen, Dalene De Beer, Marena ManleyAbstract:The phenolic quality of commercial South African fermented rooibos Iced Teas in terms of aspalathin, iso-orientin, and orientin contents in comparison to a "cup of Tea" was shown to be inferior. The role of the different manufacturing stages of powdered extract used in Iced Tea formulation and, more specifically, the impact of pasteurization and sterilization on the color and phenolic content of the beverage, were assessed as potential causes of its inferior phenolic quality. Aspalathin and its corresponding flavones, iso-orientin and orientin, were found to be present at all stages of the powdered extract production process. Spray-drying did not significantly (P ≥ 0.05) alter the aspalathin, iso-orientin, or orientin content of concentrates. Simulated normal-temperature sterilization (NTS at 121 °C/15 min) and high-temperature sterilization (HTS at 135 °C/4 min), but not necessarily pasteurization (93 °C/30 min), significantly (P < 0.05) reduced the aspalathin, iso-orientin, and orientin contents of different Iced Tea formulations. Heat-induced losses of iso-orientin and orientin were lower than those for aspalathin. Conversion of aspalathin to the flavones is implicated. The addition of ascorbic acid and/or citric acid to the base Iced Tea formulation containing only rooibos extract and sugar proved to be beneficial, especially for the retention of aspalathin. Browning, that is, absorbance at 420 nm, was significantly (P < 0.05) increased in the base formulation. In the case of the formulations also containing ascorbic acid and/or citric acid, absorbance remained unchanged or decreased when subjected to NTS and HTS treatments. This was attributed to removal of brown polymers from solution as the pH values of these formulations were lower than that of the base formulation.