[Objective] To study the effects of microwave blanching treatment on POD activity and crispness in Capsicum frutescens L., and to compare the effects of microwave blanching method, normal blanching method, boiling wat...[Objective] To study the effects of microwave blanching treatment on POD activity and crispness in Capsicum frutescens L., and to compare the effects of microwave blanching method, normal blanching method, boiling water blanching and steam blanching. [Methods] In order to obtain the optimal condition for microwave blanching, response surface methodology was used to construct a quadratic regression model describing the effects of microwave power, microwave time and calcium lactate concentration on the POD activity in C. frutescens. [Results] The optimal technology was obtained based on central composite design： 525 W microwave power, 64.5 s microwave time, and 0.08% calcium lactate concentration. Under this condition, POD enzyme activity of C. frutescens was desactivated and crispness of C. frutescens was 68.77 N. [Conclusions] This research would provide references for the crispness protection and enzyme deactivation of C. frutescens.展开更多
The study evaluated the feasibility of using microwave enhanced hot air heating system for simultaneous dry blanching and dehydration of mushroom slices. The technology involves application of microwave energy at the ...The study evaluated the feasibility of using microwave enhanced hot air heating system for simultaneous dry blanching and dehydration of mushroom slices. The technology involves application of microwave energy at the beginning of dehydration process to inactivate enzymes as well as to remove a certain amount of moisture at the same time and then followed by hot air drying to complete the process. The study investigated effects of different processing parameters, i.e., microwave power level and exposure time on dehydration and quality characteristics of mushroom slices. Mushroom slices were pretreated with different microwave power levels of 240, 360 and 480 W for 1, 3 and 5 min before the hot air-drying. The optimum range of the microwave power level and pretreatment time was found to be 360 W, 3 min and 360 W, 1 min in obtaining the maximum and minimum levels of response parameters.展开更多
A Streetcar Named Desire is regarded as one of the most successful masterpieces of Tennessee Williams. An outstanding feature of the play is the wide use of symbolism. Symbols can be seen everywhere and even all the s...A Streetcar Named Desire is regarded as one of the most successful masterpieces of Tennessee Williams. An outstanding feature of the play is the wide use of symbolism. Symbols can be seen everywhere and even all the symbols in the play are con nected with the protagonist Blanche DuBois. Williams applies symbolism throughout the play to make Blanche's tragic fate more vivid to the readers. Her tragic fate lies in her clinging to illusion, thus she is bound to be abandoned by the harsh reality. There fore, the thesis attempts to give a comprehensive analysis of some specific symbols: symbols of illusion represented by the Chinese paper lantern and a paper moon, and symbol of reality represented by the light to further illustrate Blanche's tragically symbolic fate.展开更多
A Streetcar Named Desire, which has been widely accepted as the world-renowned work of Tennessee Williams, is a play with both of complexity and charm. After its publication, this play has attracted a lot of scholars ...A Streetcar Named Desire, which has been widely accepted as the world-renowned work of Tennessee Williams, is a play with both of complexity and charm. After its publication, this play has attracted a lot of scholars and critics to interpret and study on it from the different aspects of views. The present paper attempts to certificate that the main character Blanche, in this play, who is live in a social background with the highlights of the conflict between the American southern plantation culture and the northern industrial civilization, suffers from the consistent change of her living space, her original world continually encounters destruction and invasion. Therefore, she has to step into another world; and she has to survive among different world. In addition, through digging into and interpreting the character Blanche, it investigates that people are of suffering and pain when they were in the process of adjusting and adapting themselves from their original world to their present- living world, and all Blanche's roads lead to a tragic.展开更多
An estimated 20% of the world’s population is at risk for zinc (Zn) deficiency. Micronutrient deficiencies are most prevalent in Africa and remain a major problem facing poor populations, whose impact is worsened by ...An estimated 20% of the world’s population is at risk for zinc (Zn) deficiency. Micronutrient deficiencies are most prevalent in Africa and remain a major problem facing poor populations, whose impact is worsened by HIV/AIDS pandemic. Adequate zinc nutrition is essential for adequate growth, immunocompetence and neurobehavioral development. In Sub-Saharan Africa, Zn deficiency risk stands at 34.6% with 25.6% of its population having inadequate zinc intake. It is widespread in areas where diets lack diversity and it has been implicated as a contributing factor to stunting in approximately a third of children in low-income countries. In Kenya, it is a public health problem that about 50% of children under 6 years and 50% of women are affected. Zn deficiency rates are severe and pose severe consequences whose impact would translate into poor economic development and would set a vicious cycle effect that will take many generations to correct if left unchecked. It is important to examine zinc in the diet but its concentration in food varies depending partly on processing besides other factors. The objective of this study was to assess blanching as a food preparation method’s implication to Zn levels in vegetables. Blanching is a method where vegetables are dipped in boiling water for around two minutes and removed to avoid over cooking. Zn levels in slenderleaf sp. Indigenous vegetable commonly found in the Lake Victoria Basin region is not known. An experimental study was carried out to analyze zinc levels in raw and blanched slenderleaf sp. (Crotalaria ochroleuca & Crotalaria brevidens) vegetables. Results indicated that blanching reduces Zinc levels in slenderleaf vegetables, however, the reductions are not significant;the levels after blanching are still vital. It is, therefore, recommended to minimize blanching time in order to reduce loss of the vital nutrient in slenderleaf sp. vegetables.展开更多
The study was aimed to determine the antioxidant contents and the effect of different blanching times (5 min, 10 min, 15 min and 20 min) on antioxidant contents of three different selected fresh vegetables. Three diff...The study was aimed to determine the antioxidant contents and the effect of different blanching times (5 min, 10 min, 15 min and 20 min) on antioxidant contents of three different selected fresh vegetables. Three different types of vegeta- ble were used namely Amaranthus specie locally known as spinach, namely “tete”, (Celosia argentea), soko, (Solonum nodifiorum) and odu, (Telfeira occidentalis) were analyzed for their antioxidant contents. The analysis revealed that raw vegetables have the highest amount of antioxidant contents. Telferia occidentalis had the highest antioxidant content followed by Solonum nodifiorum. It was observed that blanching time had an adverse effect on the antioxidant contents of the blanched vegetables. The antioxidant contents of tete, soko and odu were significantly decreased (p < 0.05) after blanching.展开更多
Response surface methodology and central composite rotatable design （CCRD） for K = 3 were used to investigate the combined effect of blanching time （0-1 min）, processing time （10-30 min） and sodium metabisulphi...Response surface methodology and central composite rotatable design （CCRD） for K = 3 were used to investigate the combined effect of blanching time （0-1 min）, processing time （10-30 min） and sodium metabisulphite （Na2S205） salt concentration （0%-2%） on vitamin C content, hardness （texture）, microbial count and color intensity of green pepper （Capsicum sinensis） during canning. Blanching, processing time and sodium metabisulphite （Na2S205） salt concentration all had variable effects on the vitamin C, microbial quality and sensory characteristics of the canned green peppers. Significant （P 〈 0.05） interactions were noted between all the factors with high regression coefficients （78.7%-97.0%）. Increasing processing time caused significant decreases in vitamin C and microbial load of the product. However, salt concentration had only marginal and insignificant effect on the vitamin C content of the canned product. Sensory evaluation on the product showed that both the pre-processing conditions and of blanching and salt concentrations, and the processing time had varied effects on the color and hardness of the products. Hardness of the canned products generally decreased with increasing processing time and blanching time, while only minimal and insignificant effects were noted with blanching time. Increasing blanching time caused significant increasing retention of the dark green color of the peppers with only slight but insignificant increases noted with processing time, while increases in salt concentration consistently reduced the dark green color of the products. The optimum pre-processing and processing conditions that yielded products with high preference and consumer-acceptability were： blanching time of 0 min, processing time of 10 min and sodium metabisulphite concentration of 0.2%.展开更多
A Streetcar Named Desire unfolds the tragedy of a southern lady.The conflict betwixt southern Blanche and northern Stanley is the main contradiction in the play.In the end,Stanley drives Blanche crazy and sends her to...A Streetcar Named Desire unfolds the tragedy of a southern lady.The conflict betwixt southern Blanche and northern Stanley is the main contradiction in the play.In the end,Stanley drives Blanche crazy and sends her to an asylum.This paper attempts to analyze Blanche’s identity crisis from identity negotiation theory in cross-cultural communication,including identity security,identity inclusion,and identity predictability.Thereby it figures out that one who suffers hostile gazes from others in a strange environment,is unable to carry out an intimate and effective communication,which will eventually lead to a sense of loss and despair.This paper puts forward the methods to obtain identity recognition:be honest with others,be sure of oneself,and try one’s best to fit in the new environment,aiming to help people avoid identity crisis in interpersonal communication and establish a positive identity.展开更多
Thermal blanching is an essential operation for many fruits and vegetables processing.It not only contributes to the inactivation of polyphenol oxidase(PPO),peroxidase(POD),but also affects other quality attributes of...Thermal blanching is an essential operation for many fruits and vegetables processing.It not only contributes to the inactivation of polyphenol oxidase(PPO),peroxidase(POD),but also affects other quality attributes of products.Herein we review the current status of thermal blanching.Firstly,the purposes of blanching,which include inactivating enzymes,enhancing drying rate and product quality,removing pesticide residues and toxic constituents,expelling air in plant tissues,decreasing microbial load,are examined.Then,the reason to why indicators such as POD and PPO,ascorbic acid,color,and texture are frequently used to evaluate blanching process is summarized.After that,the principles,applications and limitations of current thermal blanching methods,which include conventional hot water blanching,steam blanching,microwave blanching,ohmic blanching,and infrared blanching are outlined.Finally,future trends are identified and discussed.展开更多
Blanching is an essential step before processing of agricultural products as it can inactivate enzymes that cause undesirable changes.In current work the effects of superheated steam impingement blanching(SSIB)time an...Blanching is an essential step before processing of agricultural products as it can inactivate enzymes that cause undesirable changes.In current work the effects of superheated steam impingement blanching(SSIB)time and temperature on drying characteristics and red pigments content of line pepper were investigated.Results showed that after a 3-min SSIB pretreatment at 110℃ the pepper epidermis covered with wax coat was damaged.In addition,the drying time was extensively decreased and the loss of red pigments of dried products was reduced.Results showed that the whole drying process took place in the falling rate period,which indicated that diffusion was the dominant physical mechanism governing moisture movement in the samples.Therefore,the second Fick’s law of diffusion was used to determine the effective moisture diffusivity(Deff)of line pepper,which increased from 1.193×10^-10 to 3.128×10^-10 m^2/s with increasing of the drying temperature and air velocity.The drying activation energy(Ea)of pretreated samples was 34.31 kJ/mol,which decreased by 3% compared with the non-pretreatment group.The findings of this work indicate that SSIB is very promising pretreatment technique as it not only enhances drying process but also improves bioactive substance preservation of red pepper.展开更多
基金Supported by the Key Project of Chongqing City(cstc2014yykfA0030)~~
文摘[Objective] To study the effects of microwave blanching treatment on POD activity and crispness in Capsicum frutescens L., and to compare the effects of microwave blanching method, normal blanching method, boiling water blanching and steam blanching. [Methods] In order to obtain the optimal condition for microwave blanching, response surface methodology was used to construct a quadratic regression model describing the effects of microwave power, microwave time and calcium lactate concentration on the POD activity in C. frutescens. [Results] The optimal technology was obtained based on central composite design： 525 W microwave power, 64.5 s microwave time, and 0.08% calcium lactate concentration. Under this condition, POD enzyme activity of C. frutescens was desactivated and crispness of C. frutescens was 68.77 N. [Conclusions] This research would provide references for the crispness protection and enzyme deactivation of C. frutescens.
文摘The study evaluated the feasibility of using microwave enhanced hot air heating system for simultaneous dry blanching and dehydration of mushroom slices. The technology involves application of microwave energy at the beginning of dehydration process to inactivate enzymes as well as to remove a certain amount of moisture at the same time and then followed by hot air drying to complete the process. The study investigated effects of different processing parameters, i.e., microwave power level and exposure time on dehydration and quality characteristics of mushroom slices. Mushroom slices were pretreated with different microwave power levels of 240, 360 and 480 W for 1, 3 and 5 min before the hot air-drying. The optimum range of the microwave power level and pretreatment time was found to be 360 W, 3 min and 360 W, 1 min in obtaining the maximum and minimum levels of response parameters.
文摘A Streetcar Named Desire is regarded as one of the most successful masterpieces of Tennessee Williams. An outstanding feature of the play is the wide use of symbolism. Symbols can be seen everywhere and even all the symbols in the play are con nected with the protagonist Blanche DuBois. Williams applies symbolism throughout the play to make Blanche's tragic fate more vivid to the readers. Her tragic fate lies in her clinging to illusion, thus she is bound to be abandoned by the harsh reality. There fore, the thesis attempts to give a comprehensive analysis of some specific symbols: symbols of illusion represented by the Chinese paper lantern and a paper moon, and symbol of reality represented by the light to further illustrate Blanche's tragically symbolic fate.
文摘A Streetcar Named Desire, which has been widely accepted as the world-renowned work of Tennessee Williams, is a play with both of complexity and charm. After its publication, this play has attracted a lot of scholars and critics to interpret and study on it from the different aspects of views. The present paper attempts to certificate that the main character Blanche, in this play, who is live in a social background with the highlights of the conflict between the American southern plantation culture and the northern industrial civilization, suffers from the consistent change of her living space, her original world continually encounters destruction and invasion. Therefore, she has to step into another world; and she has to survive among different world. In addition, through digging into and interpreting the character Blanche, it investigates that people are of suffering and pain when they were in the process of adjusting and adapting themselves from their original world to their present- living world, and all Blanche's roads lead to a tragic.
文摘An estimated 20% of the world’s population is at risk for zinc (Zn) deficiency. Micronutrient deficiencies are most prevalent in Africa and remain a major problem facing poor populations, whose impact is worsened by HIV/AIDS pandemic. Adequate zinc nutrition is essential for adequate growth, immunocompetence and neurobehavioral development. In Sub-Saharan Africa, Zn deficiency risk stands at 34.6% with 25.6% of its population having inadequate zinc intake. It is widespread in areas where diets lack diversity and it has been implicated as a contributing factor to stunting in approximately a third of children in low-income countries. In Kenya, it is a public health problem that about 50% of children under 6 years and 50% of women are affected. Zn deficiency rates are severe and pose severe consequences whose impact would translate into poor economic development and would set a vicious cycle effect that will take many generations to correct if left unchecked. It is important to examine zinc in the diet but its concentration in food varies depending partly on processing besides other factors. The objective of this study was to assess blanching as a food preparation method’s implication to Zn levels in vegetables. Blanching is a method where vegetables are dipped in boiling water for around two minutes and removed to avoid over cooking. Zn levels in slenderleaf sp. Indigenous vegetable commonly found in the Lake Victoria Basin region is not known. An experimental study was carried out to analyze zinc levels in raw and blanched slenderleaf sp. (Crotalaria ochroleuca & Crotalaria brevidens) vegetables. Results indicated that blanching reduces Zinc levels in slenderleaf vegetables, however, the reductions are not significant;the levels after blanching are still vital. It is, therefore, recommended to minimize blanching time in order to reduce loss of the vital nutrient in slenderleaf sp. vegetables.
文摘The study was aimed to determine the antioxidant contents and the effect of different blanching times (5 min, 10 min, 15 min and 20 min) on antioxidant contents of three different selected fresh vegetables. Three different types of vegeta- ble were used namely Amaranthus specie locally known as spinach, namely “tete”, (Celosia argentea), soko, (Solonum nodifiorum) and odu, (Telfeira occidentalis) were analyzed for their antioxidant contents. The analysis revealed that raw vegetables have the highest amount of antioxidant contents. Telferia occidentalis had the highest antioxidant content followed by Solonum nodifiorum. It was observed that blanching time had an adverse effect on the antioxidant contents of the blanched vegetables. The antioxidant contents of tete, soko and odu were significantly decreased (p < 0.05) after blanching.
文摘Response surface methodology and central composite rotatable design （CCRD） for K = 3 were used to investigate the combined effect of blanching time （0-1 min）, processing time （10-30 min） and sodium metabisulphite （Na2S205） salt concentration （0%-2%） on vitamin C content, hardness （texture）, microbial count and color intensity of green pepper （Capsicum sinensis） during canning. Blanching, processing time and sodium metabisulphite （Na2S205） salt concentration all had variable effects on the vitamin C, microbial quality and sensory characteristics of the canned green peppers. Significant （P 〈 0.05） interactions were noted between all the factors with high regression coefficients （78.7%-97.0%）. Increasing processing time caused significant decreases in vitamin C and microbial load of the product. However, salt concentration had only marginal and insignificant effect on the vitamin C content of the canned product. Sensory evaluation on the product showed that both the pre-processing conditions and of blanching and salt concentrations, and the processing time had varied effects on the color and hardness of the products. Hardness of the canned products generally decreased with increasing processing time and blanching time, while only minimal and insignificant effects were noted with blanching time. Increasing blanching time caused significant increasing retention of the dark green color of the peppers with only slight but insignificant increases noted with processing time, while increases in salt concentration consistently reduced the dark green color of the products. The optimum pre-processing and processing conditions that yielded products with high preference and consumer-acceptability were： blanching time of 0 min, processing time of 10 min and sodium metabisulphite concentration of 0.2%.
文摘A Streetcar Named Desire unfolds the tragedy of a southern lady.The conflict betwixt southern Blanche and northern Stanley is the main contradiction in the play.In the end,Stanley drives Blanche crazy and sends her to an asylum.This paper attempts to analyze Blanche’s identity crisis from identity negotiation theory in cross-cultural communication,including identity security,identity inclusion,and identity predictability.Thereby it figures out that one who suffers hostile gazes from others in a strange environment,is unable to carry out an intimate and effective communication,which will eventually lead to a sense of loss and despair.This paper puts forward the methods to obtain identity recognition:be honest with others,be sure of oneself,and try one’s best to fit in the new environment,aiming to help people avoid identity crisis in interpersonal communication and establish a positive identity.
文摘Thermal blanching is an essential operation for many fruits and vegetables processing.It not only contributes to the inactivation of polyphenol oxidase(PPO),peroxidase(POD),but also affects other quality attributes of products.Herein we review the current status of thermal blanching.Firstly,the purposes of blanching,which include inactivating enzymes,enhancing drying rate and product quality,removing pesticide residues and toxic constituents,expelling air in plant tissues,decreasing microbial load,are examined.Then,the reason to why indicators such as POD and PPO,ascorbic acid,color,and texture are frequently used to evaluate blanching process is summarized.After that,the principles,applications and limitations of current thermal blanching methods,which include conventional hot water blanching,steam blanching,microwave blanching,ohmic blanching,and infrared blanching are outlined.Finally,future trends are identified and discussed.
基金the National Natural Science Foundation of China(Grant No.31360399)for the financial support.
文摘Blanching is an essential step before processing of agricultural products as it can inactivate enzymes that cause undesirable changes.In current work the effects of superheated steam impingement blanching(SSIB)time and temperature on drying characteristics and red pigments content of line pepper were investigated.Results showed that after a 3-min SSIB pretreatment at 110℃ the pepper epidermis covered with wax coat was damaged.In addition,the drying time was extensively decreased and the loss of red pigments of dried products was reduced.Results showed that the whole drying process took place in the falling rate period,which indicated that diffusion was the dominant physical mechanism governing moisture movement in the samples.Therefore,the second Fick’s law of diffusion was used to determine the effective moisture diffusivity(Deff)of line pepper,which increased from 1.193×10^-10 to 3.128×10^-10 m^2/s with increasing of the drying temperature and air velocity.The drying activation energy(Ea)of pretreated samples was 34.31 kJ/mol,which decreased by 3% compared with the non-pretreatment group.The findings of this work indicate that SSIB is very promising pretreatment technique as it not only enhances drying process but also improves bioactive substance preservation of red pepper.
