[Objective] The paper was to evaluate effects of peracetic acid (PAA) combined with calcium treatments on storage quality of Ioquat fruits, so as to pro- vide practical techniques to solve the problems of postharves...[Objective] The paper was to evaluate effects of peracetic acid (PAA) combined with calcium treatments on storage quality of Ioquat fruits, so as to pro- vide practical techniques to solve the problems of postharvest rot and quality deteri- oration for Ioquat fruits. [Method] With Ioquat fruits of Qingzhong variety as materi- als, 0.2%, 0.4% and 0.8% PAA combined with 0.8% CaCI2 was used to soak Ioquat fruits for 4 min, 0.8% CaCl2 and water treatments were set as two controls; the fruits were dried and packaged by 0.02 mm PE bags, then stored under non-chilling low temperature of (7±1) ℃. The indicators related to storage quality of Ioquat fruits were randomly tested once every 3 d, and their variation situations were analyzed. [Result] Compared with two control treatments and 0.2% PAA, 0.8% PAA combined with calcium treatments, the treatment of 0.4% PAA combined with 0.8% CaCl2 could significantly inhibit rot index, weight loss rate, firmness and cell membrane permeability of Ioquat fruits during storage period, which could also effectively delay the reduction of titratable acid, vitamin C, soluble solid content and juice yield, and maintain respiration intensity of fruits at a low level; the appearance and flavor qual- ity of fruits were good after stored for 25 d. [Conclusion] 0.4% PAA combined with 0.8% CaCl2 treatment is an efficient, safe and economical practice technology in an- ti-corrosion and quality preservation for postharvest Ioquat fruits .展开更多
In this study, peaches of cv. 'Sui Yuan' with different maturities were treated with 0.05 mM sodium nitroprusside (SNP), a nitric oxide donor, for 5 min, at 28℃, and then stored at 0-1.5℃ for 30 days. Untreated ...In this study, peaches of cv. 'Sui Yuan' with different maturities were treated with 0.05 mM sodium nitroprusside (SNP), a nitric oxide donor, for 5 min, at 28℃, and then stored at 0-1.5℃ for 30 days. Untreated fruits stored under the same conditions were used as control fruits in the experiment. The browning level, activities of polyphenol oxidase (PPO), peroxydase (POD) and superoxide dismutase (SOD), and quality parameters (firmness, titratable acid, total soluble solids and total sugar) were analyzed. The results showed that the firmness of SNP-treated fruit at different stage of maturity were higher than that of the control fruit after storage for 30 days. However, no significant effect was found on total soluble solid content. The titratable acid content of low maturity fruit was higher in SNP-treated one than that of the control, but the titratable acid content of high maturity fruit treated by SNP was lower than that of the control on 10th and 30th day. In addition, the combination of SNP treatment and high maturity resulted in higher activities of SOD, lower activity of PPO and POD, lower browning level. Therefore, the combination of high maturity and SNP treatment might be a useful method to well maintain honey peach fruit quality during cold storage.展开更多
[Objective] The aim was to study the coupling effect of water and phosphate on economic traits of sugarcane. [Method] Taking sugarcane variety ROC22 as tested material,coupling effects of different levels of water sup...[Objective] The aim was to study the coupling effect of water and phosphate on economic traits of sugarcane. [Method] Taking sugarcane variety ROC22 as tested material,coupling effects of different levels of water supply quantity and different levels of phosphorus fertilizer on the yield and quality of sugarcane were studied. Among them,water supply quantity had 3 levels,that was,the water supply quantity per 10 days from the early tillering stage of sugarcane to the end of elongation was 199.5 m3/hm2 (A1),400.5 m3/hm2 (A2) and 600.0 m3/hm2 (A3),respectively; Phosphorus fertilizer as basic fertilizer had 4 levels:P2O5 0 kg/hm2 (B1),120 kg/hm2 (B2),240 kg/hm2 (B3) and 360 kg/hm2 (B4). [Result] Treatment A3B2 in water-fertilizer coupling was more suitable to improve economic traits of sugarcane. [Conclusion] The research results provide theoretical basis for the efficient utilization of water and phosphorus fertilizer in production of Guangxi sugarcane and the cultivation of high-yield and high-glucose sugarcane.展开更多
Stabilized ZnTiO4 was prepared by doping magnesium oxide through traditional solid state reaction. The experimental results indicate that zinc titanate crystals doped with magnesium oxide grow well and the decompositi...Stabilized ZnTiO4 was prepared by doping magnesium oxide through traditional solid state reaction. The experimental results indicate that zinc titanate crystals doped with magnesium oxide grow well and the decomposition into Zn2TiO4 and TiO2 is restrained through traditional solid state reaction, By adjusting molar ratio of MgO, better properties can be obtained The dielectric properties of the ceramics doped with 30% MgO( molar percentage) sintered at 1060℃ are as follows:the value of quality factor is greater than 20000(6.5 GHz ), the temperature coefficient of resonance frequency is about 2 ± 10^-6 /℃,the dielectric constant ranges from 180 to 22.Besides,it is proved that heat treatment can optimize microstructure and the value of quality factor, which increases from 23833.93 to 47584.00 after 2h of heat treatment at 1040℃.展开更多
The process characteristics of heat treatment of aluminum alloy auto body sheet and the working principle of air cushion furnace were introduced.The process position and irreplaceable role of air cushion furnace in th...The process characteristics of heat treatment of aluminum alloy auto body sheet and the working principle of air cushion furnace were introduced.The process position and irreplaceable role of air cushion furnace in the aluminum alloy auto body sheet production was pointed out after the difficulty and key points in the whole production process of auto body sheet were studied.Then the development process of air cushion furnace line of aluminum alloy sheet was reviewed,summarized and divided to two stages.Based on the research of air cushion furnace,the key technology of it was analyzed,then the key points on process,equipment and control models of air cushion furnace for aluminum alloy auto body sheet in future were put forward.With the rapid development of automotive industry,there will be certainly a new upsurge of research and application of air cushion furnace for heat treatment of aluminum alloy auto body sheet.展开更多
Adsorption is an important process in wastewater treatment,and conversion of waste materials to adsorbent offers a solution to high material cost related to the use of commercial activated carbon.This study investigat...Adsorption is an important process in wastewater treatment,and conversion of waste materials to adsorbent offers a solution to high material cost related to the use of commercial activated carbon.This study investigated the adsorption behaviour of Reactive Black 5(RB5)and methylene blue(MB)onto activated carbon produced from textile sludge(TSAC).The activated carbon was synthesized through chemical activation of precursor followed with carbonization at 650℃ under nitrogen flow.Effects of time(0–200 min),pH(2–10),temperature(25–60℃),initial dye concentration(0–200 mg·L^-1),and adsorbent dosage(0.01–0.15 g)on dye removal efficiency were investigated.Preliminary screening revealed that TSAC synthesized via H2SO4activation showed higher adsorption behaviour than TSAC activated by KCl and ZnCl2.The adsorption capacity of TSAC was found to be 11.98 mg·g^-1(RB5)and 13.27 mg·g^-1(MB),and is dependent on adsorption time and initial dye concentration.The adsorption data for both dyes were well fitted to Freundlich isotherm model which explains the heterogeneous nature of TSAC surface.The dye adsorption obeyed pseudo-second order kinetic model,thus chemisorption was the controlling step.This study reveals potential of textile sludge in removal of dyes from aqueous solution,and further studies are required to establish the applicability of the synthesized adsorbent for the treatment of waste water containing toxic dyes from textile industry.展开更多
As the key point in sex hormone analysis, sample pre-treatment technology has attracted scientists' attention all over the world, and the development trend of sample preparation forwarded to faster and more effici...As the key point in sex hormone analysis, sample pre-treatment technology has attracted scientists' attention all over the world, and the development trend of sample preparation forwarded to faster and more efficient technologies. Taking economic and environmental concerns into account, subcritical fluid extraction as a faster and more efficient method has stood out as a sample pre-treatment technology. This new extraction technology can overcome the shortcomings of supercritical fluid and achieve higher extraction efficiency at relatively low pressures and temperatures. In this experiment, a simple, sensitive and efficient method has been developed for the determination of diethylstilbestrol(DES) in fish tissue using subcritical 1,1,1,2-tetrafluoroethane(R134a) extraction in combination with gas chromatography-mass spectrometry(GC-MS). After extraction, freezing-lipid filtration was utilized to remove fatty co-extract. Further purification steps were performed with C_(18) and NH_2 solid phase extraction(SPE). Finally, the analyte was derived by heptafluorobutyric anhydride(HFBA), followed by GC-MS analysis. Response surface methodology(RSM) was employed to optimizing the extraction condition, and the optimized was as follows: extraction pressure, 4.3 MPa; extraction temperature, 26℃; amount of co-solvent volume, 4.7 m L. Under this condition, at a spiked level of 1, 5, 10 μg kg^(-1), the mean recovery of DES was more than 90% with relative standard deviations(RSDs) less than 10%. Finally, the developed method has been successfully used to analyzing the real samples.展开更多
Harvested fruits of mango (Mangifera indica) suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigat...Harvested fruits of mango (Mangifera indica) suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigate the effects of fungicide treatments and storage temperatures on fruit quality of two mango cultivars, Keirt and Palmer. Mango fruits were treated with 0.04% or 0.08% v/v Triadimefon at either 53 ℃ (hot) or at room temperature and then either stored under ambient conditions (27-29 ℃) or in a refrigerator at a temperature of 11-12 ℃. Fruits stored under ambient conditions developed external colour faster than those stored at a lower temperature. Brix values for fruits treated with Triadimefon decreased with time. Fruits stored at lower temperatures gave least Brix values as compared with those stored under ambient conditions. Percentage titratable acid (%TA) of fruits stored at low temperatures increased over time. Fruits stored at lower temperatures recorded lower pH compared with fruits stored under ambient conditions. Palmer fruits recorded higher %Brix to %TA ratio, indicating a higher sweetness level. The firmness of Palmer fruits kept at lower temperatures increased with time when compared with Keitt fruit. Fruits treated with hot water at 53 ℃ and/or stored at low temperatures (11-12 ℃) had lower levels of anthracnose infection than other treatments. Keitt fruits were more susceptible to anthracnose infection than Palmer fruits. Mango fruits should therefore be treated with hot water at 53 ℃ and then stored at low temperatures (11-12 ℃) in order to slow down the rate of ripening and to reduce anthracnose infection.展开更多
The focus of this paper is to investigate different control structures(single-loop PI control) for a dividing wall(Petlyuk) column for separating ethanol, n-propanol and n-butanol. Four control structures are studied....The focus of this paper is to investigate different control structures(single-loop PI control) for a dividing wall(Petlyuk) column for separating ethanol, n-propanol and n-butanol. Four control structures are studied. All the results are simulations based on Aspen Plus. Control structure 1(CS1) is stabilizing control structure with only temperature controllers. CS2, CS3 and CS4, containing also composition controllers, are introduced to reduce the steady state composition deviations. CS2 adds a distillate composition controller(CCDB) on top of CS1. CS3 is much more complicated with three temperature-composition cascade controllers and in addition a selector to the reboiler duty to control the maximum controller output of light impurity composition control in side stream and bottom impurity control in the prefractionator. CS4 adds another high selector to control the light impurity in the sidestream. Surprisingly, when considering the dynamic and even steady state performance of the proposed control structures, CS1 proves to be the best control structure to handle feed disturbances inserted into the three-product Petlyuk column.展开更多
The main aim of this study was to explore the effects of microwave pre-treatment on quality of kenaf seed oil by observing the changes in oil yield, oxidative stability, fatty acid components, tocopherols, antioxidant...The main aim of this study was to explore the effects of microwave pre-treatment on quality of kenaf seed oil by observing the changes in oil yield, oxidative stability, fatty acid components, tocopherols, antioxidant activities and color intensity of kenaf seed oil. Microwave pre-treatment on kenaf seeds did affect the quality of the extracted oils. Microwave pre-treatment increased the extracted oil yields significantly (P 〈 0.05). Moreover, the roasted oils showed a significant increase in oxidative stability, antioxidant stability and colour of kenaf seed oils. In terms of fatty acids composition, microwave roasting had greater effect on oleic acids (C18:1) and linoleic acids (C18:2), as roasting increased the oleic acid content but decreased linoleic acid. There was no significant difference in the palmitic acids (C16:0) and stearic acids (C18:0) (P 〉 0.05). A significant decrease (P 〈 0.05) in the iodine value of the oils was found. In conclusion, kenaf seed oil roasted for 2 min had better oil quality if compared to the unroasted oil, as microwave pre-treatment improved the oil yield, oxidative stability and antioxidant activities of kenaf seed oil.展开更多
In order to study the effects of chemical osmotic pretreatment on the characteristics and quality of blueberry under hot air drying,fresh blueberries were pretreated with 2.5 g/100 mL K2CO3+0.6 g/100 mL olive oil,and ...In order to study the effects of chemical osmotic pretreatment on the characteristics and quality of blueberry under hot air drying,fresh blueberries were pretreated with 2.5 g/100 mL K2CO3+0.6 g/100 mL olive oil,and 5.0 g/100 mL K2CO3+0.6 g/100 mL olive oil at(45±0.5)℃,respectively.The changes of water content,rehydration,hardness,microstructure,color difference,active ingredient anthocyanin,total phenol and DPPH radical scavenging capacity of dried blueberries in different treatment groups under hot air drying were compared and analyzed.The results showed that the dehydration rates of blueberries vary greatly according to the type of pretreatments when the samples were dried to the same water content with hot air.Specifically,the dehydration rate of dried blueberries pretreated by 5.0%K2CO3 solution was the highest,followed by 2.5%K2CO3 osmotic pretreatment and lastly the control group;the corresponding dehydration time was 10,14 and 20h,respectively.The physical qualities of dried blueberries,involving the browning degree,color difference,rehydration and microstructure,were significantly different between the chemical osmotic pretreatment group and the control group(P<0.05).The chemical osmotic pretreatment of K2CO3 solution increased the dehydration rate of the samples,shortened the drying time and maintained the quality of blueberries dried with hot air.There was no significant difference between the physical quality of dried blueberries pretreated by 2.5%and 5.0%K2CO3 solution(P>0.05),whereas there was significant difference in drying time and nutrient quality which is characterized by total phenols,anthocyanins,DPPH radical scavenging rate,soluble total sugar(P<0.05).Conclusion:5.0%K2CO3 osmotic pretreatment combining with hot air drying can improve the dehydration rate,shorten the drying time and maintain the physical and nutritional quality.展开更多
Heat treatments such as hot-water dipping (HWD), hot water rinsing and brushing (HWRB), and hot air treatment (HAT) have been applied on a wide range of horticultural crops to control postharvest decay and to ma...Heat treatments such as hot-water dipping (HWD), hot water rinsing and brushing (HWRB), and hot air treatment (HAT) have been applied on a wide range of horticultural crops to control postharvest decay and to maintain quality characteristics. In this study we compared the influence of hot-water dipping (HWD) for 2 rain at 50℃and hot air treatment (HAT) at 37 ℃ for 30 hours, on postharvest performance of kumquat (Fortunellajaponica Lour. Swingle, cv. Ovale) fruit. Decay development, transpiration rate (fruit weight loss), external appearance, and nutritive (sugars and organic acids) and functional properties (ascorbic acid, total phenolic compounds, and total antioxidant activity) were evaluated over 21 days' simulated shelf-life at 17 ℃. Untreated fruits were used as control. There was no visible damage to the fruit following HWD or HAT and after storage. However, while HWD and control fruit maintained their fresh appearance during the first 14 days of storage and were rated as fairly fresh after the 21 days, HAT fruits had lost their gloss and no longer appeared fresh. HWD did not affect fruit weight loss while HAT induced significant weight loss with respect to control. HAT did not significantly affect decay incidence after 14 days' storage but effectively reduced decay after 21 days'. HWD notably reduced decay development after 14 and 21 days of storage and proved significantly more effective than HAT. Neither HWD nor HAT significantly affected the nutritive and functional properties of fruit. Thus, present results indicate that while HWD can be applied on kumquats to control postharvest decay without impairing the quality traits, HAT conditions (treatment time and temperature) should be optimized, due to adverse effects to fruit quality.展开更多
Cucumeropsis mannii, an underutilized oil seed was processed into raw full fat and defatted seed flours and its chemical, functional properties and anti-nutritional factors were determined using standard techniques. T...Cucumeropsis mannii, an underutilized oil seed was processed into raw full fat and defatted seed flours and its chemical, functional properties and anti-nutritional factors were determined using standard techniques. The effects of sample concentration and pH on the foaming properties of the seed flours were determined. The results showed that the full fat and defatted seed flours contained the following in g/100 g sample; 5.0 and 5.1; 45.8 and 1.0; 39.4 and 78.7; 3.45 and 4.40; 1.50 and 3.05; 4.85 and 7.75 for moisture, crude fat, protein, ash, crude fibre and carbohydrate, respectively. The most abundant mineral elements in the seed flour (mg/100 g) are potassium (198.5), followed by nickel (30.0) and magnesium (28.4). The water absorption capacity, oil absorption capacity, foaming capacity and stability, least gelation concentration, emulsion capacity and bulk density are 55.5% and 125.0%; 128.8% and 184.0%; 10.5% and 17.0%; 3.0% and 1.5%; 16.0% and 10.0 g/mL; 85.0 and 115.0 mL/g; 0.42 and 0.25 g/mL, respectively. Defatting influenced the functional properties. The foaming capacity is dependent on sample concentration and pH. The protein solubility of the full fat and defatted seed flours was minimum between pH 3 and 4 and maximum at pH 11. The anti-nutritional composition of the seed flour revealed the following: tannic acid, 1.54 mg/100 g; phytin phosphorus, 0.70 rag/g; phytic acid, 2.48 mg/g; oxalate, 1.85 mg/g; alkaloids 1.97% and saponin 0.50%. The seed flours (full fat and defatted) have potential as nutrient supplement, thickeners and emulsifiers in food system.展开更多
Protein is a major component in muscles.Biochemical or chemical changes occur during processing of fresh meat and meat products,which positively or negatively affects meat quality attributes.In this review,we discusse...Protein is a major component in muscles.Biochemical or chemical changes occur during processing of fresh meat and meat products,which positively or negatively affects meat quality attributes.In this review,we discussed research progress in three aspects:(1)protein modification,degradation and meat quality of fresh meat,(2)protein changes and quality of meat products,and(3)protein digestion.It is emphasized that protein degradation is good for meat tenderization and the production of precursors for meat flavor and taste.However,protein oxidation has the beneficial and detrimental effects in different ways.Moderate oxidation should be acceptable in terms of meat eating quality and nutritional values,but heavy oxidation should be avoided.展开更多
基金Supported by Special Fund for Agro-scientific Research in the Public Interest "Tec-hnology Research and Experimental Demonstration of Loquat Industry"(201003073)~~
文摘[Objective] The paper was to evaluate effects of peracetic acid (PAA) combined with calcium treatments on storage quality of Ioquat fruits, so as to pro- vide practical techniques to solve the problems of postharvest rot and quality deteri- oration for Ioquat fruits. [Method] With Ioquat fruits of Qingzhong variety as materi- als, 0.2%, 0.4% and 0.8% PAA combined with 0.8% CaCI2 was used to soak Ioquat fruits for 4 min, 0.8% CaCl2 and water treatments were set as two controls; the fruits were dried and packaged by 0.02 mm PE bags, then stored under non-chilling low temperature of (7±1) ℃. The indicators related to storage quality of Ioquat fruits were randomly tested once every 3 d, and their variation situations were analyzed. [Result] Compared with two control treatments and 0.2% PAA, 0.8% PAA combined with calcium treatments, the treatment of 0.4% PAA combined with 0.8% CaCl2 could significantly inhibit rot index, weight loss rate, firmness and cell membrane permeability of Ioquat fruits during storage period, which could also effectively delay the reduction of titratable acid, vitamin C, soluble solid content and juice yield, and maintain respiration intensity of fruits at a low level; the appearance and flavor qual- ity of fruits were good after stored for 25 d. [Conclusion] 0.4% PAA combined with 0.8% CaCl2 treatment is an efficient, safe and economical practice technology in an- ti-corrosion and quality preservation for postharvest Ioquat fruits .
基金supported by National Key Technology R&D Program in the 11~(th) Five year Plan of China (2006BAD22B04)
文摘In this study, peaches of cv. 'Sui Yuan' with different maturities were treated with 0.05 mM sodium nitroprusside (SNP), a nitric oxide donor, for 5 min, at 28℃, and then stored at 0-1.5℃ for 30 days. Untreated fruits stored under the same conditions were used as control fruits in the experiment. The browning level, activities of polyphenol oxidase (PPO), peroxydase (POD) and superoxide dismutase (SOD), and quality parameters (firmness, titratable acid, total soluble solids and total sugar) were analyzed. The results showed that the firmness of SNP-treated fruit at different stage of maturity were higher than that of the control fruit after storage for 30 days. However, no significant effect was found on total soluble solid content. The titratable acid content of low maturity fruit was higher in SNP-treated one than that of the control, but the titratable acid content of high maturity fruit treated by SNP was lower than that of the control on 10th and 30th day. In addition, the combination of SNP treatment and high maturity resulted in higher activities of SOD, lower activity of PPO and POD, lower browning level. Therefore, the combination of high maturity and SNP treatment might be a useful method to well maintain honey peach fruit quality during cold storage.
基金Supported by National Science and Technology Project of China(2007BAD30B04)~~
文摘[Objective] The aim was to study the coupling effect of water and phosphate on economic traits of sugarcane. [Method] Taking sugarcane variety ROC22 as tested material,coupling effects of different levels of water supply quantity and different levels of phosphorus fertilizer on the yield and quality of sugarcane were studied. Among them,water supply quantity had 3 levels,that was,the water supply quantity per 10 days from the early tillering stage of sugarcane to the end of elongation was 199.5 m3/hm2 (A1),400.5 m3/hm2 (A2) and 600.0 m3/hm2 (A3),respectively; Phosphorus fertilizer as basic fertilizer had 4 levels:P2O5 0 kg/hm2 (B1),120 kg/hm2 (B2),240 kg/hm2 (B3) and 360 kg/hm2 (B4). [Result] Treatment A3B2 in water-fertilizer coupling was more suitable to improve economic traits of sugarcane. [Conclusion] The research results provide theoretical basis for the efficient utilization of water and phosphorus fertilizer in production of Guangxi sugarcane and the cultivation of high-yield and high-glucose sugarcane.
基金SUPPORTED BY NATIONAL NATURAL SCIENCE FOUNDATION OF CHINA( NO. 50172035).
文摘Stabilized ZnTiO4 was prepared by doping magnesium oxide through traditional solid state reaction. The experimental results indicate that zinc titanate crystals doped with magnesium oxide grow well and the decomposition into Zn2TiO4 and TiO2 is restrained through traditional solid state reaction, By adjusting molar ratio of MgO, better properties can be obtained The dielectric properties of the ceramics doped with 30% MgO( molar percentage) sintered at 1060℃ are as follows:the value of quality factor is greater than 20000(6.5 GHz ), the temperature coefficient of resonance frequency is about 2 ± 10^-6 /℃,the dielectric constant ranges from 180 to 22.Besides,it is proved that heat treatment can optimize microstructure and the value of quality factor, which increases from 23833.93 to 47584.00 after 2h of heat treatment at 1040℃.
文摘The process characteristics of heat treatment of aluminum alloy auto body sheet and the working principle of air cushion furnace were introduced.The process position and irreplaceable role of air cushion furnace in the aluminum alloy auto body sheet production was pointed out after the difficulty and key points in the whole production process of auto body sheet were studied.Then the development process of air cushion furnace line of aluminum alloy sheet was reviewed,summarized and divided to two stages.Based on the research of air cushion furnace,the key technology of it was analyzed,then the key points on process,equipment and control models of air cushion furnace for aluminum alloy auto body sheet in future were put forward.With the rapid development of automotive industry,there will be certainly a new upsurge of research and application of air cushion furnace for heat treatment of aluminum alloy auto body sheet.
基金the Ministry of Higher Education,Malaysia(MOHE)for the financial supports received under University Grant(08H05)and Fundamental Research Grant Scheme(4F872)Universiti Teknologi Malaysia for the GUP grant No.17H65the support to the main author,Wong Syie Luing,in the form of Post-Doctoral Fellowship Scheme for the project"Catalytic Cracking of Low Density Polyethylene Waste to Liquid Fuels in Fixed Bed Reactor"
文摘Adsorption is an important process in wastewater treatment,and conversion of waste materials to adsorbent offers a solution to high material cost related to the use of commercial activated carbon.This study investigated the adsorption behaviour of Reactive Black 5(RB5)and methylene blue(MB)onto activated carbon produced from textile sludge(TSAC).The activated carbon was synthesized through chemical activation of precursor followed with carbonization at 650℃ under nitrogen flow.Effects of time(0–200 min),pH(2–10),temperature(25–60℃),initial dye concentration(0–200 mg·L^-1),and adsorbent dosage(0.01–0.15 g)on dye removal efficiency were investigated.Preliminary screening revealed that TSAC synthesized via H2SO4activation showed higher adsorption behaviour than TSAC activated by KCl and ZnCl2.The adsorption capacity of TSAC was found to be 11.98 mg·g^-1(RB5)and 13.27 mg·g^-1(MB),and is dependent on adsorption time and initial dye concentration.The adsorption data for both dyes were well fitted to Freundlich isotherm model which explains the heterogeneous nature of TSAC surface.The dye adsorption obeyed pseudo-second order kinetic model,thus chemisorption was the controlling step.This study reveals potential of textile sludge in removal of dyes from aqueous solution,and further studies are required to establish the applicability of the synthesized adsorbent for the treatment of waste water containing toxic dyes from textile industry.
基金supported by the National Natural Science Foundation of China (31071541)a program for Changjiang Scholars and Innovative Research Team in University (IRT1188)
文摘As the key point in sex hormone analysis, sample pre-treatment technology has attracted scientists' attention all over the world, and the development trend of sample preparation forwarded to faster and more efficient technologies. Taking economic and environmental concerns into account, subcritical fluid extraction as a faster and more efficient method has stood out as a sample pre-treatment technology. This new extraction technology can overcome the shortcomings of supercritical fluid and achieve higher extraction efficiency at relatively low pressures and temperatures. In this experiment, a simple, sensitive and efficient method has been developed for the determination of diethylstilbestrol(DES) in fish tissue using subcritical 1,1,1,2-tetrafluoroethane(R134a) extraction in combination with gas chromatography-mass spectrometry(GC-MS). After extraction, freezing-lipid filtration was utilized to remove fatty co-extract. Further purification steps were performed with C_(18) and NH_2 solid phase extraction(SPE). Finally, the analyte was derived by heptafluorobutyric anhydride(HFBA), followed by GC-MS analysis. Response surface methodology(RSM) was employed to optimizing the extraction condition, and the optimized was as follows: extraction pressure, 4.3 MPa; extraction temperature, 26℃; amount of co-solvent volume, 4.7 m L. Under this condition, at a spiked level of 1, 5, 10 μg kg^(-1), the mean recovery of DES was more than 90% with relative standard deviations(RSDs) less than 10%. Finally, the developed method has been successfully used to analyzing the real samples.
文摘Harvested fruits of mango (Mangifera indica) suffer from both physiological and pathological deterioration in quality during storage which consequently affects their market value. A study was conducted to investigate the effects of fungicide treatments and storage temperatures on fruit quality of two mango cultivars, Keirt and Palmer. Mango fruits were treated with 0.04% or 0.08% v/v Triadimefon at either 53 ℃ (hot) or at room temperature and then either stored under ambient conditions (27-29 ℃) or in a refrigerator at a temperature of 11-12 ℃. Fruits stored under ambient conditions developed external colour faster than those stored at a lower temperature. Brix values for fruits treated with Triadimefon decreased with time. Fruits stored at lower temperatures gave least Brix values as compared with those stored under ambient conditions. Percentage titratable acid (%TA) of fruits stored at low temperatures increased over time. Fruits stored at lower temperatures recorded lower pH compared with fruits stored under ambient conditions. Palmer fruits recorded higher %Brix to %TA ratio, indicating a higher sweetness level. The firmness of Palmer fruits kept at lower temperatures increased with time when compared with Keitt fruit. Fruits treated with hot water at 53 ℃ and/or stored at low temperatures (11-12 ℃) had lower levels of anthracnose infection than other treatments. Keitt fruits were more susceptible to anthracnose infection than Palmer fruits. Mango fruits should therefore be treated with hot water at 53 ℃ and then stored at low temperatures (11-12 ℃) in order to slow down the rate of ripening and to reduce anthracnose infection.
基金Supported by the National Basic Research Program of China(973 Program:2012CB720500)the National Supporting Research Program of China(Grant2013BAA03B01)+2 种基金the National Natural Science Foundation of China(21176178)the China Scholarship Council(201506250011)the China Postdoctoral Science Foundation(2017M620587)
文摘The focus of this paper is to investigate different control structures(single-loop PI control) for a dividing wall(Petlyuk) column for separating ethanol, n-propanol and n-butanol. Four control structures are studied. All the results are simulations based on Aspen Plus. Control structure 1(CS1) is stabilizing control structure with only temperature controllers. CS2, CS3 and CS4, containing also composition controllers, are introduced to reduce the steady state composition deviations. CS2 adds a distillate composition controller(CCDB) on top of CS1. CS3 is much more complicated with three temperature-composition cascade controllers and in addition a selector to the reboiler duty to control the maximum controller output of light impurity composition control in side stream and bottom impurity control in the prefractionator. CS4 adds another high selector to control the light impurity in the sidestream. Surprisingly, when considering the dynamic and even steady state performance of the proposed control structures, CS1 proves to be the best control structure to handle feed disturbances inserted into the three-product Petlyuk column.
文摘The main aim of this study was to explore the effects of microwave pre-treatment on quality of kenaf seed oil by observing the changes in oil yield, oxidative stability, fatty acid components, tocopherols, antioxidant activities and color intensity of kenaf seed oil. Microwave pre-treatment on kenaf seeds did affect the quality of the extracted oils. Microwave pre-treatment increased the extracted oil yields significantly (P 〈 0.05). Moreover, the roasted oils showed a significant increase in oxidative stability, antioxidant stability and colour of kenaf seed oils. In terms of fatty acids composition, microwave roasting had greater effect on oleic acids (C18:1) and linoleic acids (C18:2), as roasting increased the oleic acid content but decreased linoleic acid. There was no significant difference in the palmitic acids (C16:0) and stearic acids (C18:0) (P 〉 0.05). A significant decrease (P 〈 0.05) in the iodine value of the oils was found. In conclusion, kenaf seed oil roasted for 2 min had better oil quality if compared to the unroasted oil, as microwave pre-treatment improved the oil yield, oxidative stability and antioxidant activities of kenaf seed oil.
基金Supported by Science and Technology Innovation Project in Hunan Academy of Agricultural Sciences(2017JC66)International Science and Technology Innovation Cooperation Base Construction Project in Hunan(2018WK4011)~~
文摘In order to study the effects of chemical osmotic pretreatment on the characteristics and quality of blueberry under hot air drying,fresh blueberries were pretreated with 2.5 g/100 mL K2CO3+0.6 g/100 mL olive oil,and 5.0 g/100 mL K2CO3+0.6 g/100 mL olive oil at(45±0.5)℃,respectively.The changes of water content,rehydration,hardness,microstructure,color difference,active ingredient anthocyanin,total phenol and DPPH radical scavenging capacity of dried blueberries in different treatment groups under hot air drying were compared and analyzed.The results showed that the dehydration rates of blueberries vary greatly according to the type of pretreatments when the samples were dried to the same water content with hot air.Specifically,the dehydration rate of dried blueberries pretreated by 5.0%K2CO3 solution was the highest,followed by 2.5%K2CO3 osmotic pretreatment and lastly the control group;the corresponding dehydration time was 10,14 and 20h,respectively.The physical qualities of dried blueberries,involving the browning degree,color difference,rehydration and microstructure,were significantly different between the chemical osmotic pretreatment group and the control group(P<0.05).The chemical osmotic pretreatment of K2CO3 solution increased the dehydration rate of the samples,shortened the drying time and maintained the quality of blueberries dried with hot air.There was no significant difference between the physical quality of dried blueberries pretreated by 2.5%and 5.0%K2CO3 solution(P>0.05),whereas there was significant difference in drying time and nutrient quality which is characterized by total phenols,anthocyanins,DPPH radical scavenging rate,soluble total sugar(P<0.05).Conclusion:5.0%K2CO3 osmotic pretreatment combining with hot air drying can improve the dehydration rate,shorten the drying time and maintain the physical and nutritional quality.
文摘Heat treatments such as hot-water dipping (HWD), hot water rinsing and brushing (HWRB), and hot air treatment (HAT) have been applied on a wide range of horticultural crops to control postharvest decay and to maintain quality characteristics. In this study we compared the influence of hot-water dipping (HWD) for 2 rain at 50℃and hot air treatment (HAT) at 37 ℃ for 30 hours, on postharvest performance of kumquat (Fortunellajaponica Lour. Swingle, cv. Ovale) fruit. Decay development, transpiration rate (fruit weight loss), external appearance, and nutritive (sugars and organic acids) and functional properties (ascorbic acid, total phenolic compounds, and total antioxidant activity) were evaluated over 21 days' simulated shelf-life at 17 ℃. Untreated fruits were used as control. There was no visible damage to the fruit following HWD or HAT and after storage. However, while HWD and control fruit maintained their fresh appearance during the first 14 days of storage and were rated as fairly fresh after the 21 days, HAT fruits had lost their gloss and no longer appeared fresh. HWD did not affect fruit weight loss while HAT induced significant weight loss with respect to control. HAT did not significantly affect decay incidence after 14 days' storage but effectively reduced decay after 21 days'. HWD notably reduced decay development after 14 and 21 days of storage and proved significantly more effective than HAT. Neither HWD nor HAT significantly affected the nutritive and functional properties of fruit. Thus, present results indicate that while HWD can be applied on kumquats to control postharvest decay without impairing the quality traits, HAT conditions (treatment time and temperature) should be optimized, due to adverse effects to fruit quality.
文摘Cucumeropsis mannii, an underutilized oil seed was processed into raw full fat and defatted seed flours and its chemical, functional properties and anti-nutritional factors were determined using standard techniques. The effects of sample concentration and pH on the foaming properties of the seed flours were determined. The results showed that the full fat and defatted seed flours contained the following in g/100 g sample; 5.0 and 5.1; 45.8 and 1.0; 39.4 and 78.7; 3.45 and 4.40; 1.50 and 3.05; 4.85 and 7.75 for moisture, crude fat, protein, ash, crude fibre and carbohydrate, respectively. The most abundant mineral elements in the seed flour (mg/100 g) are potassium (198.5), followed by nickel (30.0) and magnesium (28.4). The water absorption capacity, oil absorption capacity, foaming capacity and stability, least gelation concentration, emulsion capacity and bulk density are 55.5% and 125.0%; 128.8% and 184.0%; 10.5% and 17.0%; 3.0% and 1.5%; 16.0% and 10.0 g/mL; 85.0 and 115.0 mL/g; 0.42 and 0.25 g/mL, respectively. Defatting influenced the functional properties. The foaming capacity is dependent on sample concentration and pH. The protein solubility of the full fat and defatted seed flours was minimum between pH 3 and 4 and maximum at pH 11. The anti-nutritional composition of the seed flour revealed the following: tannic acid, 1.54 mg/100 g; phytin phosphorus, 0.70 rag/g; phytic acid, 2.48 mg/g; oxalate, 1.85 mg/g; alkaloids 1.97% and saponin 0.50%. The seed flours (full fat and defatted) have potential as nutrient supplement, thickeners and emulsifiers in food system.
基金supported by the National Natural Science Foundation of China(Grant No.31530054)
文摘Protein is a major component in muscles.Biochemical or chemical changes occur during processing of fresh meat and meat products,which positively or negatively affects meat quality attributes.In this review,we discussed research progress in three aspects:(1)protein modification,degradation and meat quality of fresh meat,(2)protein changes and quality of meat products,and(3)protein digestion.It is emphasized that protein degradation is good for meat tenderization and the production of precursors for meat flavor and taste.However,protein oxidation has the beneficial and detrimental effects in different ways.Moderate oxidation should be acceptable in terms of meat eating quality and nutritional values,but heavy oxidation should be avoided.