酸法醇介质制备木薯淀粉糊精的工艺及特性研究

以木薯淀粉为原料制备木薯淀粉糊精。木薯淀粉在80～81℃温度下,以不同浓度盐酸(2%、3%、4%)、不同浓度的乙醇水解液介质(70%、80%、90%)、不同水解时间(1～5h)进行不同条件的水解。实验测定了水解过程中淀粉的水解程度、DE值、糊精粘度和颗粒微观结构的变化情况。结果表明:在相同乙醇浓度下,随着酸浓度增加,水解程度升高。酸解淀粉糊精的黏度与原淀粉相比数值下降。以2%、4%、6%盐酸处理制备的糊精粒子微观结构无明显变化。70%和80%乙醇介质中反应产物的DE值较相对应的90%乙醇介质中低,通过正交试验确定了水解适宜的工艺条件,酸解的最佳工艺条件为盐酸6%、乙醇浓度90%、时间3h。     

酸-乙醇介质制备木薯淀粉糊精的工艺及其优化

以木薯淀粉为原料制备木薯淀粉糊精。木薯淀粉在79～81℃温度下．以不同浓度盐酸（2％、4％、6％）、不同浓度的乙醇水解液介质（70％、80％、90％）和不同水解时间（2．5h、3h、3．5h）进行了不同条件的试验水解。测定了酸水解过程中淀粉的DE值，确定了它们酸水解适宜的工艺条件：盐酸6％、乙醇浓度90％、时间3h。     

酸法醇介质制备红薯淀粉糊精的工艺及特性研究

以红薯淀粉为原料制备红薯淀粉糊精。红薯淀粉在79～81℃温度下,以不同浓度盐酸(2%、3%、4%)、不同浓度的乙醇水解液介质(75%、85%、95%)、不同水解时间(1～5h)进行不同条件的水解。实验测定了水解过程中淀粉的水解程度、DE值、糊精黏度和颗粒微观结构的变化情况。结果表明:在相同乙醇浓度下,随着酸浓度增加,水解程度升高。酸解淀粉糊精的黏度与原淀粉相比数值下降。以2%、4%、6%盐酸处理制备的糊精粒子微观结构无明显变化。75%和85%乙醇介质中反应产物的DE值较相对应的95%乙醇介质中低,通过正交实验确定了水解适宜的工艺条件,酸解的最佳工艺条件为盐酸6%、乙醇浓度95%、时间3h。     

超声波对玉米淀粉分子结构影响

研究淀粉颗粒经超声波处理后,淀粉分子量分布变化、直链淀粉与支链淀粉组分变化。结果表明,随着超声波时间延长,淀粉水解率逐渐增加,支链淀粉分子量显著降低,直链淀粉含量升高,形成新的直链淀粉脂质复合物。     

用β-淀粉酶制备蜡质大米糊精及其性质研究

以蜡质大米淀粉为原料,经过β-淀粉酶处理得到不同水解程度的糊精,并对其理化性质进行了研究。研究表明,在实验设定的条件下,控制β-淀粉酶用量为65 U/g不变,处理时间为20 h时淀粉水解率达到最大为56.7%;扫描电镜测试显示,蜡质大米淀粉为多角形的小颗粒,经糊化-酶解后的样品颗粒形貌被破坏,随着水解程度的增加,碎片数量越多;经过β-淀粉酶的水解,淀粉-碘吸附曲线的最高吸收峰位置偏移,样品与碘的吸附能力均低于原淀粉,且随着水解程度增加吸附能力下降;随着水解程度的增加糊精的大分子部分逐渐减少,小分子部分增加;在同一温度下酶解后淀粉样品的溶解度高于原淀粉,膨胀度则相反,随着水解程度和温度的增加溶解度和膨胀度呈增加趋势;酶解后淀粉样品的透明度明显高于原淀粉,但随水解程度的增加透明度下降。     

变性木薯淀粉糊精的制备工艺及其性质研究

以木薯淀粉为原料,采用醇介质酸水解制备变性木薯淀粉糊精.通过正交试验确定了淀粉糊精的制备条件,并对此条件下得到的产品进行了性质研究.结果表明,该产品持水性比原淀粉大,吸湿性较强,感官及其理化特性符合麦芽糖标准,酸解淀粉糊精的粘度与原淀粉相比数值下降,酸处理制备的糊精粒子微观结构无明显变化.     

盐酸水解制备木薯微孔淀粉的研究

利用盐酸水解制备木薯微孔淀粉。研究盐酸浓度、反应时间、反应温度对微孔淀粉吸附性能的影响,并通过扫描电镜（SEM）、比表面积研究（BET）、热失重分析（TGA）等手段研究微孔淀粉的结构。结果表明：盐酸处理木薯淀粉后形成微孔,且木薯微孔淀粉的比表面积远远大于木薯淀粉的比表面积。盐酸水解木薯淀粉的最优化工艺为：4.0%HCl、反应温度45℃、反应时间为8h。     

酸法优化木薯微孔淀粉的工艺及性能研究

利用盐酸对木薯淀粉进行处理,通过L9（3^4）正交实验,研究盐酸质量分数、反应时间、反应温度和搅拌速度对微孔淀粉吸附性能的影响,并通过差示扫描量热分析（DSC）、X射线衍射分析（XRD）研究微孔淀粉的结构。结果表明：盐酸制备木薯微孔淀粉的最佳工艺条件是：盐酸质量分数2．0％,反应时间8h,反应温度40℃,搅拌速度为1500r／min。通过XRD、DSC分析发现：木薯微孔淀粉的结晶部分比例增加。     

双酶协同水解制备木薯微孔淀粉的结构研究

为木薯微孔淀粉的工业化生产提供依据,用双酶协同水解制备木薯微孔淀粉。通过扫描电镜(SEM)、比表面积(BET)、X射线衍射分析(XRD)、热重分析(TGA)等手段研究微孔淀粉的结构。研究表明,双酶协同水解处理木薯淀粉后形成微孔,且木薯微孔淀粉的比表面积远远大于木薯淀粉的比表面积。与原淀粉相比,木薯微孔淀粉的热稳定性降低,结晶部分所占的比例增加。     

木薯醋酸酯淀粉的制备与表征

用醋酸酐为酯化剂、甲苯-4-磺酸为催化剂在水溶剂体系中,对木薯淀粉进行酯化变性,制得木薯醋酸酯淀粉。通过单因素试验得到制备木薯醋酸酯淀粉的较佳工艺条件为:醋酸酐质量分数15%、催化剂质量分数1.5%、反应时间3h、反应温度45℃、浴比1∶3。傅里叶红外光谱分析证实淀粉酯化变性的发生;扫描电镜显示酯化反应不仅发生在淀粉表面,还发生在淀粉颗粒内部;X射线衍射表明酯化反应破坏淀粉的部分结晶结构,结晶度从37.79%下降到29.76%;差示扫描量热法表明淀粉酯化变性改善其熔融性能,熔融温度较原淀粉下降了22.3℃。     

Effect of Acid‐Methanol Treatment on the Physicochemical and Structural Characteristics of Cassava and Maize Starches

Physicochemical, structural and morphological characteristics of maize and cassava starches treated with 0.36% concentrated HCl in anhydrous methanol at 54ºC for 1–8 h were analyzed and compared. Average yield of modified starch was about 97% for both starches. The solubility of the acid‐methanol treated starches increased with temperature and after 3 h of treatment reached 93% for maize starch and 97% for cassava starch at 95ºC. After 8 h of treatment, the average size of the cassava starch granules decreased from 14.9 to 11.1 µm. The action of acid‐methanol on the maize starch was more subtle, reducing the granule average size from 11.8 to 11.3 µm. Scanning electron micrographs showed that the granule surfaces were rough and exfoliated after treatment suggesting exocorrosion that was more evident for cassava starch. From GPC, it was noted that amylose and amylopectin were partially degraded during treatment. Starch crystallinity gradually increased with duration of treatment. The amylose content decreased from 21.4 to 18.8% and from 26.3 to 23.0% and the intrinsic viscosity was reduced from 2.36 to 0.21 and from 1.85 to 0.04 for cassava and maize starches, respectively. The gelatinization temperatures increased whereas pasting viscosities decreased with reaction time, especially for cassava starch. These results suggested that the attack of acid‐methanol, which was more effective on cassava starch granules, occurred preferentially in the amorphous areas located in the granule periphery and composed of amylose and amylopectin.     

New insights into loss of swelling power and pasting profiles of acid hydrolyzed starch granules

The effect of acid hydrolysis on the swelling power of pea starch granules was studied by field emission SEM (FE‐SEM). The swelling power of the native starch granules (g water absorbed/g dry starch) was 13, and this decreased to less than 2 after 1 day of acid hydrolysis. The proportion of the starch that was soluble in hot water increased from 15% for native starch to 75% after 1 day of hydrolysis. The swelling power of the starch decreased further, and solubility increased, with more extended hydrolysis. The decrease in swelling power and increase in solubility were attributed mainly to the disruption of side chains of amylopectin. Observations with FE‐SEM indicated that starch granules were still able to melt and coalesce after 1 day of acid hydrolysis, but after 2 days solubilization of starch chains occurred predominantly rather than swelling when the granules were heated in excess water. The intactness of amylopectin is proposed to play a crucial role in the swelling power of starch granules and in the structure of granule ghosts.     

不同物理方法处理对碎米中淀粉特性的影响

采用挤压、微波、超声波三种物理方法对水分含量18%的碎米淀粉进行处理,研究分析碎米淀粉经物理方法处理前后的理化性质和结构变化。结果表明,碎米淀粉经微波和超声处理后酶解力增加,糊化黏度下降,而溶解度、膨胀力、糊化温度和直链淀粉含量变化不显著;两种淀粉颗粒表面棱角减少,淀粉颗粒晶型基本没有发生变化,淀粉结晶区降低。挤压后的碎米淀粉变化较大,颗粒形状为片状,凝沉性强,1.0 h后体积仅为3 mL,糊化温度明显降低至55.0 ℃,直链淀粉含量增长为30.75%,溶解度强,为0.59%,酶解力达到45%,X-射线主要衍射峰的强度降低。     

Physicochemical Changes in Cassava Starch and Flour Associated With Fermentation: Effect on Textural Properties

Physicochochemical changes in cassava starch and flour associated with fermentation were investigated and related to textural properties of its flour pastes. Cyanide and pH decreased, while crude protein, acidity, and apparent amylose content increased in the fermented products. Average starch granule diameter, solubility, and swelling power were depressed, while gelatinization enthalpy increased. Amylograph of starch showed increased peak visocity temperature, reduced peak, breakdown, and setback viscosities, while Texture Profile Analysis showed a decreased in hardness, cohesiveness, elasticity, and gumminess of the fermented flour paste. The altered textural properties were attributed to greater starch granule stability due to short amylose-like fragments formed by enzymatic hydrolysis of amylopectin.     

微波辐射对木薯淀粉性质影响

研究微波辐射前后木薯淀粉物化性质变化,采用微波对30%水分含量木薯淀粉进行处理,结果表明,微波处理增强对应X–射线衍射峰强度,降低膨胀度、溶解度和冻融稳定性;木薯淀粉经处理后糊化起始温度升高、粘度降低,但其粘度曲线不改变。以上数据表明,在淀粉颗粒内无定形区和结晶区直链淀粉与直链淀粉、直链淀粉与支链淀粉发生交互作用,微波处理使淀粉分子发生一定程度降解。     

菠萝蜜种子淀粉消化特性与糊性质的研究

以菠萝蜜种子为原料提取淀粉,研究淀粉的消化特性以及糊性质。结果表明:菠萝蜜种子淀粉具有较低的消化性,抗酶解能力强;通过扫描电镜观察,发现α-淀粉酶作用不同的淀粉,其酶解方式不同,对菠萝蜜种子淀粉是通过淀粉表面进行侵蚀的作用方式酶解,而对于玉米淀粉则通过淀粉颗粒通道酶解颗粒内部;淀粉糊属于假塑性流体,其抗剪切能力比玉米淀粉,木薯淀粉强,其凝沉性比玉米淀粉小,比木薯淀粉大。     

绿豆微孔淀粉酶法制备工艺优化研究

以水解率为指标,研究α-淀粉酶与糖化酶复合水解绿豆淀粉制备微孔淀粉工艺条件,通过单因素和正交试验确定酶解最佳工艺条件：α-淀粉酶：糖化酶=1：3,酶用量2．0%,时间20 h,温度42℃,pH4．2。经吸水、吸油率测试,对酶解前后绿豆淀粉进行性质分析表明,微孔淀粉吸水、吸油能力明显大于原淀粉。     

Physicochemical properties of waxy and normal corn starches treated in different anhydrous alcohols with hydrochloric acid

Corn starches (25 g, d. b.) were treated in anhydrous methanol, ethanol, 2-propanol or 1-butanol (100 ml) with 1 ml 36% hydrochloric acid at 45 °C for 1 h, the molecular weight and chain length distributions of starch were examined by high-performance size-exclusion chromatography (HPSEC), and the granule size, granular structure, λ_max, blue value, solubility and gelatinization thermal properties of starch were also examined. Results showed the recovery yields of the treated starch were higher than 96%, and the granule sizes of treated starches were slightly lower than their counterpart native starch. Starches after acid-alcohol treated showed internal fissures or cavities in some granules, and the number of granule with fissures or cavities increased with the increasing carbon number of alcohol. The weight average degree of polymerization and relative content of F1 fraction of starch after treated profoundly decreased, and the amylose and long chain of amylopectin of starch were preferentially degraded. The degradation extent of molecules after acid-alcohol treatment was found directly related to the alternation of internal structure of starch granule. The λ_max and blue value of both waxy and normal corn starches after treated also obviously decreased with the increasing carbon number of alcohol, while the solubility of starch profoundly increased after treated. The gelatinization onset temperature (T_o) of acid-alcohol treated waxy corn starch decreased with the increasing carbon number of alcohol, but the treated normal corn starches showed similar T_o values. Despite the alcohol used, the solubility of treated waxy corn starch linearly correlated (r²=0.983) with T/T_o value (T was the measuring temperature used for solubility determination). Whereas, normal corn starch treated in different alcohols showed distinct relations between T/T_o and solubility.     

Ordered structure and thermal property of acid-modified high-amylose rice starch

High-amylose cereal starch has a great benefit on human health. Acid modification is very helpful for application of high-amylose starch in food and non-food industries. In this study, the ordered structure of acid-modified high-amylose rice starch was investigated by GPC, HPAEC, ¹³C CP/MAS NMR and XRD. Acid preferentially degraded the amylose, then A chain and short B chain of amylopectin. Relative double helix content and crystallinity both initially increased sharply and then progressively with acid hydrolysis. The relative crystallinity of starches obtained from ¹³C CP/MAS NMR was higher than that from XRD. The onset gelatinisation temperature decreased, while the peak and conclusion temperatures increased with increasing hydrolysis time. The endothermic value initially increased and then decreased with acid hydrolysis. The swelling power decreased while solubility increased after acid hydrolysis. These results add to our understanding of the effect of acid hydrolysis on the high-amylose rice starch.     

In vitro digestibility and physicochemical properties of Arenga pinnata starch-chitosan following heat-moisture treatment

In vitro digestibility and physicochemical properties of chitosan (CS)-modified Arenga pinnata starch (APS) after heat-moisture treatment (HMT) were evaluated. HMT would limit the enzymatic hydrolysis of APS and the digestion rate of HMT-APS-CS was further reduced with the decrease of CS molecular weight. CS and HMT inhibited the solubility (SOL) and swelling power (SP) of APS, and the inhibition effect was more obvious with the decrease in CS molecular weight. Changes in the pasting properties of the CS-modified APS indicated that the initial structure of the APS granules was destroyed with the formation of a denser structure. The increase of the relative crystallinity and the aggregation of the APS granules were related to starch cross-linking confirmed by Fourier transform infrared. The interactions between CS and APS granules after HMT greatly altered granular morphology and internal structure of APS. Therefore, the improvements of SDS and RS of HMT-APS-CS were mainly related to CS covering the surface of the APS granules, granule aggregation and HMT-induced changes in the internal structure of the starch granule.