The heat intolerance and retrogradation behavior of native wheat starch(WS)are undesirable for starch-based gel foods,therefore the combinations of WS and hydrocolloids have attracted extensive attentions.The objectiv...The heat intolerance and retrogradation behavior of native wheat starch(WS)are undesirable for starch-based gel foods,therefore the combinations of WS and hydrocolloids have attracted extensive attentions.The objectives of this study were to investigate the effects of konjac glucomannan(KGM)with different degree of deacetylation(DD)on the pasting,rheological and retrogradation properties of WS.Results showed that deacetyl-konjac glucomannan(DKGM)increased the peak viscosity(PV),trough viscosity(TV)and final viscosity(FV),while decreased the breakdown(BD)values of WS,suggesting the enhancement of the viscosity and thermal stability of WS paste.The raised storage modulus(G′)of WS gels with DKGM1(DD,48.23%)demonstrated that the partial removal of acetyl groups from KGM chains effectively promoted the formation of gel network,accompanied by increased elasticity.After storing at 4℃ for 7 days,the hardness of gels increased up 369%,while supplement with DKGM significantly(p<0.05)decreased the hardness.These data demonstrated that DKGM delayed the process of starch retrogradation,which was further verified by LF-NMR analysis.Besides,the addition of DKGM reduced the retrogradation rate,relative crystallinity and the orderliness of WS-DKGM gels with the prolonging of storage at 4℃,all validating the hindrance of starch retrogradation by DKGM.Therefore,these data suggested that partial deacetylation of KGM could effectively improve the pasting,rheological characteristics and impede the retrogradation of WS.展开更多
This paper presents experimental results on the effect of alkalis such as NaOH, KOH and Ca（OH）2 on deacetylation of a konjac glucomannan （KGM） powder under mechano-chemical （MC） treatment, The results show that ...This paper presents experimental results on the effect of alkalis such as NaOH, KOH and Ca（OH）2 on deacetylation of a konjac glucomannan （KGM） powder under mechano-chemical （MC） treatment, The results show that the alkalinity of modifiers is a dominant factor for deacetylation of KGM, In addition, characteristics, such as swelling property, viscous stability and thermal behavior of the deacetylated KGM are analyzed展开更多
采用碱性溶剂对魔芋葡甘聚糖(Kon jac G lucom annan,KGM)进行了脱乙酰处理,采用原子力显微镜、圆二色谱表征了脱乙酰KGM的链结构的变化特点,并对其膜材料的性能进行了测试。结果表明KGM脱乙酰基后,从半柔性直链分子转化成为弹性微球状...采用碱性溶剂对魔芋葡甘聚糖(Kon jac G lucom annan,KGM)进行了脱乙酰处理,采用原子力显微镜、圆二色谱表征了脱乙酰KGM的链结构的变化特点,并对其膜材料的性能进行了测试。结果表明KGM脱乙酰基后,从半柔性直链分子转化成为弹性微球状,特性粘度大大降低,非对称性增加,表明有序结构的形成。上述结构的变化赋予材料性能的提高,KGM脱乙酰后显示了较强的力学性能,膜的拉伸强度、断裂伸长率分别提高了151%、19%,吸湿增重降低53%。展开更多
基金This study was supported by the National Key Research and Development Program of China during the 13th Five-Year Plan(2018YFD0400501)Key Research and development plan for Colleges and Universities in Henan Province(20A550013).
文摘The heat intolerance and retrogradation behavior of native wheat starch(WS)are undesirable for starch-based gel foods,therefore the combinations of WS and hydrocolloids have attracted extensive attentions.The objectives of this study were to investigate the effects of konjac glucomannan(KGM)with different degree of deacetylation(DD)on the pasting,rheological and retrogradation properties of WS.Results showed that deacetyl-konjac glucomannan(DKGM)increased the peak viscosity(PV),trough viscosity(TV)and final viscosity(FV),while decreased the breakdown(BD)values of WS,suggesting the enhancement of the viscosity and thermal stability of WS paste.The raised storage modulus(G′)of WS gels with DKGM1(DD,48.23%)demonstrated that the partial removal of acetyl groups from KGM chains effectively promoted the formation of gel network,accompanied by increased elasticity.After storing at 4℃ for 7 days,the hardness of gels increased up 369%,while supplement with DKGM significantly(p<0.05)decreased the hardness.These data demonstrated that DKGM delayed the process of starch retrogradation,which was further verified by LF-NMR analysis.Besides,the addition of DKGM reduced the retrogradation rate,relative crystallinity and the orderliness of WS-DKGM gels with the prolonging of storage at 4℃,all validating the hindrance of starch retrogradation by DKGM.Therefore,these data suggested that partial deacetylation of KGM could effectively improve the pasting,rheological characteristics and impede the retrogradation of WS.
文摘This paper presents experimental results on the effect of alkalis such as NaOH, KOH and Ca（OH）2 on deacetylation of a konjac glucomannan （KGM） powder under mechano-chemical （MC） treatment, The results show that the alkalinity of modifiers is a dominant factor for deacetylation of KGM, In addition, characteristics, such as swelling property, viscous stability and thermal behavior of the deacetylated KGM are analyzed
文摘采用碱性溶剂对魔芋葡甘聚糖(Kon jac G lucom annan,KGM)进行了脱乙酰处理,采用原子力显微镜、圆二色谱表征了脱乙酰KGM的链结构的变化特点,并对其膜材料的性能进行了测试。结果表明KGM脱乙酰基后,从半柔性直链分子转化成为弹性微球状,特性粘度大大降低,非对称性增加,表明有序结构的形成。上述结构的变化赋予材料性能的提高,KGM脱乙酰后显示了较强的力学性能,膜的拉伸强度、断裂伸长率分别提高了151%、19%,吸湿增重降低53%。
