Starch/polylactic acid(PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other...Starch/polylactic acid(PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other properties of the composites were studied. The combination of results of TGA with SEM indicated that the interdependence between starch and PLA was increased gradually as the starch/PLA ratio reduced. DSC results showed that the glass transition temperature(Tg), melting temperature(Tm) and degree of crystallinity of PLA in composites were increased gradually, whereas the cold crystallization temperature(Tc) was gradually decreased as the starch/PLA ratio reduced. The rheological properties of composites were closely related with the interdependence of two-phase, with reducing starch/PLA proportion, the interdependence was increased, and then the strain for storage modulus was firstl reduced and then gradually increased. Frequency scanning showed that the storage modulus and complex viscosity were decreased with reducing starch content. As the starch/PLA ratio reduced, the matrix phase PLA was increased, so that the strength of composites was increased gradually, whereas water absorption rate was decreased gradually.展开更多
Ethylene glycol, glycerol, sorbitol, formamide, and urea were used as plasticizers for the preparation of thermoplastic starch(TPS) from corn starch. The properties of TPS were tested by analysis method. The results...Ethylene glycol, glycerol, sorbitol, formamide, and urea were used as plasticizers for the preparation of thermoplastic starch(TPS) from corn starch. The properties of TPS were tested by analysis method. The results showed that TPSs were more highly plasticized with amines than alcohols. For the same type of plasticizer, the degree of plasticization decreased as the molecular weight of plasticizer increased. The relationship between plasticization degree and TPS properties was characterized and described by mechanical properties and water absorption. The experimental results showed that when the degree of plasticization increased, the tensile strength decreased and the elongation at breakage and water absorption increased.展开更多
Objective:The influence of two experimental starches - ginger starch obtained from Zingiber officinale and banana starch from Musa sapientum - on the mechanical and disintegration properties of chloroquine tablets hav...Objective:The influence of two experimental starches - ginger starch obtained from Zingiber officinale and banana starch from Musa sapientum - on the mechanical and disintegration properties of chloroquine tablets have been studied in comparison with the influence of official corn starch.Methods:Chloroquine tablets were formulated using various concentarions of the starches as binding agent.The mechanical properties of the tablets were assessed in terms of crushing strength and friability and the crushing strength-friability ratio(CSFR) while drug release properties were evaluated based on disintegration and the time of tablets.Results:The ranking for crushing strength and CSFR was corn】banana】ginger starch while the ranking was reverse for friability.The disintegration time increased with packing fraction and starch concentration in the rank order of formulations containing corn】banana】ginger starch.The CSFR/DT values increased with concentration of starch binder indicating an improved balance between binding and disintegrant properties of the starches.Statistical analysis showed that there were significant(P【0.001) difference in the CSFR/DT for tablets containing the various starch binders.Conclusion:The mechanical and disintegration properties of the experimental starches compared favorably with those of corn starch and ginger starch could be more useful when faster tablet disintegration is desired.展开更多
Rheological properties of corn starch and sodium alginate blend solutions have been measured at different polymer ratios in the temperature range from 303 to 343 K bya R/S Brook field rheometer with аcoaxial cylinder...Rheological properties of corn starch and sodium alginate blend solutions have been measured at different polymer ratios in the temperature range from 303 to 343 K bya R/S Brook field rheometer with аcoaxial cylinder measuring unit. Dynamic viscosity of blends has been shown to decrease with shear rate increase and to increase with sodium alginate content increase. The influence of shear rate on activation energy of viscous flow depends on sodium alginate content and is different for below and over 5% (mass) content. Applicability of Ostwald-de-Waele, Herschel-Bulkley, Bingham and Casson models for the description of CS:SA blend solutions flow has been analyzed. Rheological properties of CS:SA blend solutions allow one to look at them as an alternative to starch solutions for edible films casting and production by dry method.展开更多
为改善鱿鱼鱼糜制品的凝胶特性,优化玉米变性淀粉(乙酰化二淀粉磷酸酯(acetylated distarch phosphate,ADSP))和非肌肉蛋白(蛋清蛋白(egg white protein,EWP)、大豆分离蛋白(soy protein isolate,SPI))的添加量,并分析玉米变性淀粉协同...为改善鱿鱼鱼糜制品的凝胶特性,优化玉米变性淀粉(乙酰化二淀粉磷酸酯(acetylated distarch phosphate,ADSP))和非肌肉蛋白(蛋清蛋白(egg white protein,EWP)、大豆分离蛋白(soy protein isolate,SPI))的添加量,并分析玉米变性淀粉协同非肌肉蛋白(ADSP-EWP-SPI,AES)对鱿鱼鱼糜制品的质构、分子间作用力、蛋白质二级结构、微观结构的影响,探究AES改善鱿鱼鱼糜制品凝胶品质的机理。结果表明:ADSP、EWP和SPI添加量分别为10%、7%和6%时,鱿鱼鱼糜制品的凝胶特性最好;与对照组相比,添加玉米变性淀粉和非肌肉蛋白后,鱿鱼鱼糜制品中蛋白质的无规卷曲和α-螺旋相对含量下降,β-折叠和β-转角相对含量增加,添加AES有利于热凝胶过程中β-折叠和β-转角结构的保留,促进蛋白质之间的疏水相互作用,形成更加致密的鱼糜凝胶网络结构,提高鱿鱼鱼糜制品的凝胶强度和持水性。相关性分析显示,鱿鱼鱼糜制品的凝胶强度和持水性、疏水相互作用、β-转角及不易流动水相对含量均呈极显著正相关(P<0.01),与自由水相对含量和无规卷曲相对含量呈极显著负相关(P<0.01)。因此,添加10%ADSP、7%EWP和6%SPI通过影响鱿鱼鱼糜制品中的蛋白质二级结构和水分分布,改善了鱿鱼鱼糜制品的凝胶品质。展开更多
基金Funded by the National Forestry Public Welfare Industry Major Projects of Scientific Research(No.201504502)National Natural Science Foundation of China(No.31200442)Supported by the Post Doctorate Research from the Ministry of Science and Technology of China(No.2014M550178)
文摘Starch/polylactic acid(PLA) composites were prepared by melt extrusion, with corn starch and PLA as raw materials, glycerol as the plasticizer. Effects of starch/PLA ratio on the interdependence of two-phase and other properties of the composites were studied. The combination of results of TGA with SEM indicated that the interdependence between starch and PLA was increased gradually as the starch/PLA ratio reduced. DSC results showed that the glass transition temperature(Tg), melting temperature(Tm) and degree of crystallinity of PLA in composites were increased gradually, whereas the cold crystallization temperature(Tc) was gradually decreased as the starch/PLA ratio reduced. The rheological properties of composites were closely related with the interdependence of two-phase, with reducing starch/PLA proportion, the interdependence was increased, and then the strain for storage modulus was firstl reduced and then gradually increased. Frequency scanning showed that the storage modulus and complex viscosity were decreased with reducing starch content. As the starch/PLA ratio reduced, the matrix phase PLA was increased, so that the strength of composites was increased gradually, whereas water absorption rate was decreased gradually.
基金Funded by the Fundamental Research Funds for the Central Universities(DL13CB13)the China Postdoctoral Science Foundation Funded Project(No.2014M550178)the National Natural Science Foundation of China(No.31200442)
文摘Ethylene glycol, glycerol, sorbitol, formamide, and urea were used as plasticizers for the preparation of thermoplastic starch(TPS) from corn starch. The properties of TPS were tested by analysis method. The results showed that TPSs were more highly plasticized with amines than alcohols. For the same type of plasticizer, the degree of plasticization decreased as the molecular weight of plasticizer increased. The relationship between plasticization degree and TPS properties was characterized and described by mechanical properties and water absorption. The experimental results showed that when the degree of plasticization increased, the tensile strength decreased and the elongation at breakage and water absorption increased.
基金supported by University of Ibadan Senate Research Grant to O.A.Odeku
文摘Objective:The influence of two experimental starches - ginger starch obtained from Zingiber officinale and banana starch from Musa sapientum - on the mechanical and disintegration properties of chloroquine tablets have been studied in comparison with the influence of official corn starch.Methods:Chloroquine tablets were formulated using various concentarions of the starches as binding agent.The mechanical properties of the tablets were assessed in terms of crushing strength and friability and the crushing strength-friability ratio(CSFR) while drug release properties were evaluated based on disintegration and the time of tablets.Results:The ranking for crushing strength and CSFR was corn】banana】ginger starch while the ranking was reverse for friability.The disintegration time increased with packing fraction and starch concentration in the rank order of formulations containing corn】banana】ginger starch.The CSFR/DT values increased with concentration of starch binder indicating an improved balance between binding and disintegrant properties of the starches.Statistical analysis showed that there were significant(P【0.001) difference in the CSFR/DT for tablets containing the various starch binders.Conclusion:The mechanical and disintegration properties of the experimental starches compared favorably with those of corn starch and ginger starch could be more useful when faster tablet disintegration is desired.
文摘Rheological properties of corn starch and sodium alginate blend solutions have been measured at different polymer ratios in the temperature range from 303 to 343 K bya R/S Brook field rheometer with аcoaxial cylinder measuring unit. Dynamic viscosity of blends has been shown to decrease with shear rate increase and to increase with sodium alginate content increase. The influence of shear rate on activation energy of viscous flow depends on sodium alginate content and is different for below and over 5% (mass) content. Applicability of Ostwald-de-Waele, Herschel-Bulkley, Bingham and Casson models for the description of CS:SA blend solutions flow has been analyzed. Rheological properties of CS:SA blend solutions allow one to look at them as an alternative to starch solutions for edible films casting and production by dry method.
文摘为改善鱿鱼鱼糜制品的凝胶特性,优化玉米变性淀粉(乙酰化二淀粉磷酸酯(acetylated distarch phosphate,ADSP))和非肌肉蛋白(蛋清蛋白(egg white protein,EWP)、大豆分离蛋白(soy protein isolate,SPI))的添加量,并分析玉米变性淀粉协同非肌肉蛋白(ADSP-EWP-SPI,AES)对鱿鱼鱼糜制品的质构、分子间作用力、蛋白质二级结构、微观结构的影响,探究AES改善鱿鱼鱼糜制品凝胶品质的机理。结果表明:ADSP、EWP和SPI添加量分别为10%、7%和6%时,鱿鱼鱼糜制品的凝胶特性最好;与对照组相比,添加玉米变性淀粉和非肌肉蛋白后,鱿鱼鱼糜制品中蛋白质的无规卷曲和α-螺旋相对含量下降,β-折叠和β-转角相对含量增加,添加AES有利于热凝胶过程中β-折叠和β-转角结构的保留,促进蛋白质之间的疏水相互作用,形成更加致密的鱼糜凝胶网络结构,提高鱿鱼鱼糜制品的凝胶强度和持水性。相关性分析显示,鱿鱼鱼糜制品的凝胶强度和持水性、疏水相互作用、β-转角及不易流动水相对含量均呈极显著正相关(P<0.01),与自由水相对含量和无规卷曲相对含量呈极显著负相关(P<0.01)。因此,添加10%ADSP、7%EWP和6%SPI通过影响鱿鱼鱼糜制品中的蛋白质二级结构和水分分布,改善了鱿鱼鱼糜制品的凝胶品质。