The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Thudnatkorn Jiratanan - One of the best experts on this subject based on the ideXlab platform.
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antioxidant activity of processed table beets beta vulgaris var conditiva and Green Beans phaseolus vulgaris l
Journal of Agricultural and Food Chemistry, 2004Co-Authors: Thudnatkorn JiratananAbstract:It has been shown that thermal processing of tomatoes and sweet corn results in increased antioxidant activities despite the loss of vitamin C. Until now, it is unclear whether this positive effect of thermal processing occurs with all crop produce. Therefore, analysis of a root vegetable (beets) and of a legume (Green Beans) was undertaken to address this question. Antioxidant activity of beets processed under typical commercial processing conditions remained constant despite an 8% loss of vitamin C, a 60% loss of color, and 30% loss of dietary folate. There was a slight but significant 5% increase in phenolic content of processed beets. In contrast, vitamin C and dietary folate content of Green Beans remained constant, whereas a 32% reduction in phenolic compounds occurred after typical commercial processing conditions. The antioxidant activity of Green Beans was reduced by 20%. These findings along with previous works suggest that the effects of thermal processing vary with the respective produce crop ...
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antioxidant activity of processed table beets beta vulgaris var conditiva and Green Beans phaseolus vulgaris l
Journal of Agricultural and Food Chemistry, 2004Co-Authors: Thudnatkorn Jiratanan, Rui Hai LiuAbstract:It has been shown that thermal processing of tomatoes and sweet corn results in increased antioxidant activities despite the loss of vitamin C. Until now, it is unclear whether this positive effect of thermal processing occurs with all crop produce. Therefore, analysis of a root vegetable (beets) and of a legume (Green Beans) was undertaken to address this question. Antioxidant activity of beets processed under typical commercial processing conditions remained constant despite an 8% loss of vitamin C, a 60% loss of color, and 30% loss of dietary folate. There was a slight but significant 5% increase in phenolic content of processed beets. In contrast, vitamin C and dietary folate content of Green Beans remained constant, whereas a 32% reduction in phenolic compounds occurred after typical commercial processing conditions. The antioxidant activity of Green Beans was reduced by 20%. These findings along with previous works suggest that the effects of thermal processing vary with the respective produce crop type. It also reinforces the concept that optimal health benefits may be achieved when a wide variety of plant foods (fruits, vegetables and whole grains) and preparation methods are incorporated into the diet.
Rui Hai Liu - One of the best experts on this subject based on the ideXlab platform.
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antioxidant activity of processed table beets beta vulgaris var conditiva and Green Beans phaseolus vulgaris l
Journal of Agricultural and Food Chemistry, 2004Co-Authors: Thudnatkorn Jiratanan, Rui Hai LiuAbstract:It has been shown that thermal processing of tomatoes and sweet corn results in increased antioxidant activities despite the loss of vitamin C. Until now, it is unclear whether this positive effect of thermal processing occurs with all crop produce. Therefore, analysis of a root vegetable (beets) and of a legume (Green Beans) was undertaken to address this question. Antioxidant activity of beets processed under typical commercial processing conditions remained constant despite an 8% loss of vitamin C, a 60% loss of color, and 30% loss of dietary folate. There was a slight but significant 5% increase in phenolic content of processed beets. In contrast, vitamin C and dietary folate content of Green Beans remained constant, whereas a 32% reduction in phenolic compounds occurred after typical commercial processing conditions. The antioxidant activity of Green Beans was reduced by 20%. These findings along with previous works suggest that the effects of thermal processing vary with the respective produce crop type. It also reinforces the concept that optimal health benefits may be achieved when a wide variety of plant foods (fruits, vegetables and whole grains) and preparation methods are incorporated into the diet.
Cristina L. M. Silva - One of the best experts on this subject based on the ideXlab platform.
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Effect of ozone on the quality of fresh-cut Green Beans (Phaseolus vulgaris L.) and bell peppers (Capsicum annuum L.)
2005Co-Authors: Elisaberte M. C. Alexandre, Joana F. Fundo, Dora M. Santos, Teresa R. S. Brandão, Cristina L. M. SilvaAbstract:Ozone is recognized as a strong oxidant and potent disinfecting agent. Ozone has several applications in the food industry, such as food surface desinfection, sanitation of food plant equipment and reuse of wastewater. Ozone acts at cell level, oxidizing sulfhydryl groups and amino acids of enzymes, peptides and proteins to shorter peptides. Another proposed mechanism involves oxidation of polyunsaturated fatty acids to peroxides (Victorin, 1992). Several studies demonstrated that ozone treatments increase shelf life of fruits and vegetables (Rice et al., 1982). This fact may be explained by the antimicrobial effect of ozone and also by its potential action at enzymatic level. Enzyme activity is responsible for quality decay of foods. One of the most effective processes for enzyme inactivation is blanching, which has as the main disadvantage, the degradation of sensorial attributes of foods. Ozone may be used as an alternative non-thermal process. The objective of this work was to study the effect of ozone on the quality of fresh-cut Green Beans (Phaseolus vulgaris, L.) and Green and red bell peppers (Capsicum annuum, L.). The quality factors analysed were enzyme (peroxidase) activity, colour and texture for Green Beans, and colour, texture and pH for bell peppers. Experiments were carried out using pilot equipment. An ozone generator (SPO3, OZ5) was interconnected to a container (158 L) filled with tap water. Ozone was continuously incorporated in water at 15 oC and its content indirectly measured by potential difference. Green Beans and bell peppers were cut in small portions (2x1 cm for Green Beans; 4x10 cm for bell peppers). Samples were immersed in ozonated and non-ozonated water baths and removed after different times, till a maximum of 180 minutes. Data from both treatments were compared by analysis of variance. For Green Beans, results showed that ozone treatment did not affect the colour, but significantly influenced texture (firmness) and peroxidase inactivation (at 7% significance level). After 40 minutes enzyme activity was reduced approximately 20%. This inactivation was verified for the rest of the sampling times. Ozone treatment only affected the pH and texture (fracturability) of red bell peppers (at 1% significance level). The other quality factors were not significantly influenced by ozone.
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Green Beans (Phaseolus vulgaris, L.) quality loss upon thawing
Journal of Food Engineering, 2004Co-Authors: Rui C. Martins, Cristina L. M. SilvaAbstract:Abstract Frozen Green Beans ( Phaseolus vulgaris , L.) thawing is one of the operations that compromises significantly quality. The present research aims at studying the effects of thawing, at environmental and refrigeration temperatures, on the quality profile of a frozen Green Beans package. Quality losses were computationally evaluated, using a simulation system based on object-oriented technologies. Simulations show that sensory parameters, such as flavour and colour, are more sensitive to thawing at environmental temperatures, than nutritional parameters, such as vitamin C and starch contents. The study demonstrates that Green Beans quality retention is also influenced by packaging materials, with different degrees of thermal insulation, and environmental conditions, such as temperature and surface heat convection coefficients. Important conclusions are discussed on shelf-life limiting quality parameters during thawing and temperature abuses, as well as on thawing Green vegetables to maximise their quality profile. Results emphasise that the principle of high-temperature–short-times is not directly applicable to frozen Green Beans thawing. Furthermore, simulations lead to the conclusion that overall quality profile is maximised by thawing under refrigeration temperatures.
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Modelling colour and chlorophyll losses of frozen Green Beans (Phaseolus vulgaris, L.).
International Journal of Refrigeration, 2002Co-Authors: Rui C. Martins, Cristina L. M. SilvaAbstract:Abstract Colour changes and chlorophyll degradation of frozen Green Beans (Phaseolus vulgaris, L., variety bencanta) were studied during 250 days of storage at −7, −15 and −30 °C. Chlorophyll a and b losses and colour Hunter a and b co-ordinates and total colour difference (TCDH) changes were successfully described by first order and reversible first order models, respectively. The temperature effect was described by the Arrhenius law. Disagreement between the colour co-ordinates and chlorophyll content was obtained. Therefore, chlorophyll content is not a good colour index of frozen Green Beans. The results emphasise that colour is a more important parameter to assess frozen Green Beans visual quality.
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Texture losses of Green Beans along frozen storage
2000Co-Authors: Rui C. Martins, Cristina L. M. SilvaAbstract:The texture loss of frozen Green Beans ( Phaseolus vulgaris, L., variety Bencanta) was macroscopically evaluated by a puncture test, using the INSTRON (Universal Testing Machine, model 4500) with a 4,85 mm diameter plunger, along 250 days of isothermal storage at -7, -15 and -30°C. The force deformation curves were recorded for data analysis of: i) Energy the area below the force deformation curve, as a measurement of the resistance to compression by the plunger, ii) Stress at the failure point pressure at the failure point, as an index of firmness and iii) Stiffness -Stress / Strain, both at the failure point. The force deformation curves exhibit a decrease in the resistance to compression, with storage time at all studied temperatures. For longer periods of storage, the well-defined failure point, that is a characteristic of fresh Green Beans, decreases in Stress magnitude and increases in Strain, corresponding to the softening of Green Beans initia texture.The softening of the Green Beans tissues was assessed by the decrease in Energy, Stress and Stiffness along storage time and at the three studied temperatures. This texture loss has an exponential behaviour, with a residual value of texture that is maintained for a long period of storage. Thus, the softening process was modelled with a first reversible order kinetics. The kinetic parameters were estimated by nonlinear regression to all data, maximising the likelihood function and solving the normal equations by the Gauss-Newton algorithm. Although the high biological variability observed in the texture of Green Beans influence the precision of the estimated kinetic parameters, the temperature effec was well described by an Arrhenius behaviour. This research work lead to the conclusion that the softening of frozen stored Green Beans, is an irreversible degradation of texture, and is an important quality attribute, that can be macroscopically described.
Hans Steinhart - One of the best experts on this subject based on the ideXlab platform.
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Correlations of ingredients with sensory attributes in Green Beans and peas under different storage conditions
Food Chemistry, 2007Co-Authors: Matthias Berger, Torben Küchler, Andrea Maaßen, Mechthild Busch-stockfisch, Hans SteinhartAbstract:Abstract The total ascorbic acid contents and the antioxidant capacity in Green Beans and in peas were measured during deep-frozen storage and compared to storage at 4 °C and 20 °C. In Green Beans only, the flavonols quercetin and kaempferol were measured. The results were correlated with sensory attributes which were evaluated at the same storage stages. The total ascorbic acid content is a good parameter for the storage time of both vegetables and showed, for peas, a positive correlation with the attribute “sweet taste” and a negative correlation with the attribute “musty” odour. The total ascorbic acid content of Green Beans was positively correlated with a “squeaky” texture and negatively with a “musty” taste. The flavonol content and the antioxidant capacity were more stable during the storage process and showed less correlation with sensory attributes.
Rui C. Martins - One of the best experts on this subject based on the ideXlab platform.
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Green Beans (Phaseolus vulgaris, L.) quality loss upon thawing
Journal of Food Engineering, 2004Co-Authors: Rui C. Martins, Cristina L. M. SilvaAbstract:Abstract Frozen Green Beans ( Phaseolus vulgaris , L.) thawing is one of the operations that compromises significantly quality. The present research aims at studying the effects of thawing, at environmental and refrigeration temperatures, on the quality profile of a frozen Green Beans package. Quality losses were computationally evaluated, using a simulation system based on object-oriented technologies. Simulations show that sensory parameters, such as flavour and colour, are more sensitive to thawing at environmental temperatures, than nutritional parameters, such as vitamin C and starch contents. The study demonstrates that Green Beans quality retention is also influenced by packaging materials, with different degrees of thermal insulation, and environmental conditions, such as temperature and surface heat convection coefficients. Important conclusions are discussed on shelf-life limiting quality parameters during thawing and temperature abuses, as well as on thawing Green vegetables to maximise their quality profile. Results emphasise that the principle of high-temperature–short-times is not directly applicable to frozen Green Beans thawing. Furthermore, simulations lead to the conclusion that overall quality profile is maximised by thawing under refrigeration temperatures.
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Modelling colour and chlorophyll losses of frozen Green Beans (Phaseolus vulgaris, L.).
International Journal of Refrigeration, 2002Co-Authors: Rui C. Martins, Cristina L. M. SilvaAbstract:Abstract Colour changes and chlorophyll degradation of frozen Green Beans (Phaseolus vulgaris, L., variety bencanta) were studied during 250 days of storage at −7, −15 and −30 °C. Chlorophyll a and b losses and colour Hunter a and b co-ordinates and total colour difference (TCDH) changes were successfully described by first order and reversible first order models, respectively. The temperature effect was described by the Arrhenius law. Disagreement between the colour co-ordinates and chlorophyll content was obtained. Therefore, chlorophyll content is not a good colour index of frozen Green Beans. The results emphasise that colour is a more important parameter to assess frozen Green Beans visual quality.
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Texture losses of Green Beans along frozen storage
2000Co-Authors: Rui C. Martins, Cristina L. M. SilvaAbstract:The texture loss of frozen Green Beans ( Phaseolus vulgaris, L., variety Bencanta) was macroscopically evaluated by a puncture test, using the INSTRON (Universal Testing Machine, model 4500) with a 4,85 mm diameter plunger, along 250 days of isothermal storage at -7, -15 and -30°C. The force deformation curves were recorded for data analysis of: i) Energy the area below the force deformation curve, as a measurement of the resistance to compression by the plunger, ii) Stress at the failure point pressure at the failure point, as an index of firmness and iii) Stiffness -Stress / Strain, both at the failure point. The force deformation curves exhibit a decrease in the resistance to compression, with storage time at all studied temperatures. For longer periods of storage, the well-defined failure point, that is a characteristic of fresh Green Beans, decreases in Stress magnitude and increases in Strain, corresponding to the softening of Green Beans initia texture.The softening of the Green Beans tissues was assessed by the decrease in Energy, Stress and Stiffness along storage time and at the three studied temperatures. This texture loss has an exponential behaviour, with a residual value of texture that is maintained for a long period of storage. Thus, the softening process was modelled with a first reversible order kinetics. The kinetic parameters were estimated by nonlinear regression to all data, maximising the likelihood function and solving the normal equations by the Gauss-Newton algorithm. Although the high biological variability observed in the texture of Green Beans influence the precision of the estimated kinetic parameters, the temperature effec was well described by an Arrhenius behaviour. This research work lead to the conclusion that the softening of frozen stored Green Beans, is an irreversible degradation of texture, and is an important quality attribute, that can be macroscopically described.
