Preparation of water‐soluble starch oligomers from variable starch species in 1‐allyl‐3‐methylimidazolium chloride

Native wheat, barley, rice, maize, wx maize, and potato starch species were modified by depolymerization in 1‐allyl‐3‐methylimidazolium chloride ([AMIM]Cl) ionic liquid (IL) using oil bath or microwave heating. Reactions were catalyzed with p‐toluenesulfonic acid (p‐TsOH). Reaction times varied depending on the starch species and its concentration, the heating method, and volume of the reaction mixture. Depolymerization products were analyzed with HPLC‐ELSD. All starch species mostly degraded into water‐soluble 1500–2000 Da‐sized starch oligomers. Glucose and other short‐chained sugars did not precipitate along with starch oligomers due to their high solubility in IL. This property was utilized in the purification of commercial maltodextrins. Produced water‐soluble, low MW starch oligomers might be used, e.g., in bacterial cultivations as a glucose source.     

Binding of amino acids to hypochlorite‐oxidized potato starch

Novel starch derivatives were prepared by derivatization of oxidized potato starch with amino acids in aqueous suspension. Potato starch was oxidized using sodium hypochlorite and then reacted with amino acids under mildly alkaline conditions. By analysis of increased nitrogen content and by means of confocal laser scanning microscopy, efficient binding of positively charged amino acids to oxidized starch molecules was confirmed. A degree of substitution (DS) of up to 0.015 was obtained using oxidized starch (degree of oxidation (DO) of up to 1.0%) and positively charged amino acids (2–5%, dry starch basis) at reaction conditions of starch/water ratio of 1:2–2.5, pH 10, 40°C, 30–60 min. The DS was positively correlated with the DO of the starch. Derivatization of oxidized starch using amino acids generally enhanced the influence of oxidation on starch pasting characteristics, perhaps showing interesting functional properties and potential industrial application.     

Effects of fatty acid and emulsifier on the complex formation and in vitro digestibility of gelatinized potato starch

The effects of fatty acid, monoacylglycerol, and polyglycerol fatty acid ester with varying chain length in their acyl chains on the extent of complex formation (complex index) and in vitro enzymatic digestibility of gelatinized potato starch were investigated. The complex index increased with increase in the concentration of the ligands (fatty acid, monoacylglycerol, and polyglycerol fatty acid ester), with the plateau in the complex index value depending on the type of ligands. In comparison of complex index among fatty acid-samples, the complex index maximum increased as the chain length increased up to octanoic acid and then decreased. In comparison of complex index among fatty acid-, monoacylglycerol-, and polyglycerol fatty acid ester-samples at each acyl chain, the complex index maximum followed the order polyglycerol fatty acid ester > monoacylglycerol > fatty acid. Fatty acid, monoacylglycerol, and polyglycerol fatty acid ester with long acyl chains greatly reduced the enzymatic hydrolysis of starch. Polyglycerol fatty acid ester with palmitic acid chains was the strongest inhibitor of starch hydrolysis, suggesting that further complex formation may occur during the hydrolysis of gelatinized starch (enzyme-annealing).     

高取代度羧甲基小麦淀粉制备工艺的优化及表征

摘 要：以小麦淀粉为原料,以氯乙酸作为醚化剂,采用两次加碱法制备了高取代度的羧甲基小麦淀粉。以4.05g淀粉为基准,采用正交实验对反应条件进行了优化,得到的最佳工艺条件为：水用量6mL,无水乙醇用量60mL,氯乙酸与淀粉摩尔比1.4,氢氧化钠与氯乙酸摩尔比1.8,碱化用氢氧化钠百分比70%,碱化温度35～40℃,碱化时间0.5～1h,醚化温度50～55℃,醚化时间2～3h,在此条件下制得了取代度高达1.21的羧甲基小麦淀粉。     

Physicochemical properties of octenyl succinic anhydride‐modified potato starch with different degrees of substitution

BACKGROUND: Esterified starch is an important type of modified starch. In particular, octenyl succinic anhydride‐modified starch (OSA starch) is widely used in the food industry. However, there has been little research on the properties of products with different degrees of substitution (DS). Therefore the aim of this study was to analyse the physicochemical properties of products with different DS. RESULTS: OSA starch samples with different DS were prepared from potato starch. Two new peaks were observed in the Fourier transform infrared spectrum, one at 1724 cm^?1 due to C?O and one at 1572 cm^?1 due to RCOO? . Emulsifying capacity and emulsion stability improved with increasing DS. Rheological analysis showed the occurrence of the ‘shear‐thinning’ phenomenon, the viscosity of the sample with DS = 0.0211 being even lower than that of native starch. A decrease in syneresis rate from 88.3% (native starch) to 39.0% (DS = 0.0211) indicated that freeze–thaw stability was improved. CONCLUSION: The physicochemical properties of OSA potato starch were better than those of native potato starch. Freeze–thaw stability, emulsifying capacity and emulsion stability improved with increasing DS. Viscosity increased at lower DS but decreased at DS = 0.0211. Copyright © 2009 Society of Chemical Industry     

Gelatinization and pasting properties of rice starch modified with 2‐octen–1‐ylsuccinic anhydride

Rice starch was modified with various levels of 2‐octen‐1‐ylsuccinic anhydride (OSA). Treatments with OSA at 3, 5, and 10% resulted in starch derivatives with 0.016, 0.033, and 0.070 degrees of substitution (DS( respectively. Thermovisco properties of the derivatives were investigated by differential scanning calorimetry (DSC) and rapid visco analysis (RVA). Water content in the sample was found to have a significant effect on the characteristics of the DSC endotherm. Pasting properties of the OSA‐starch and the effect of pH and salt on the RVA profiles were also studied. In general, with increased OSA‐modification, the starch derivatives swelled and gelatinized at lower temperatures to achieve higher viscosities. Specifically, based on DSC analysis at 80% water, the peak temperature of gelatinization decreased from 68.5 to 63.2°C as the OSA modification increased in DS from 0 (intact starch) to 0.070. On the other hand, RVA results indicate that, for samples undergoing similar increase in OSA modification, the pasting temperature decreased from 88.7 to 51.5°C and the peak viscosity increased from 668 to 6822 cP.     

Effect of processing conditions on producing a reactive derivative from β‐cyclodextrin with itaconic acid

A reactive cyclodextrin was synthesised by reacting β‐cyclodextrin with itaconic acid to enable it to fix permanently onto cellulosic materials. Because synthesis is a complicated process that is greatly influenced by many factors, the response surface methodology was applied in this study to optimise production. To investigate the efficiency of the esterification reaction, the amount of carboxyl groups and the double bond content of the end product were measured and employed as the responses. The 3D response surface plots and the contour plots derived from the mathematical models were applied to evaluate the interactive effects of parameters affecting the reaction, such as itaconic acid and catalyst concentrations, material to liquor ratio, temperature and time of reaction. The amount of carboxyl groups and the double bond content of cyclodextrin itaconate (about 175 and 150 meq./100 g CDI, respectively) in the optimum conditions indicated that one to two itaconic acid molecules could react with cyclodextrin according to the esterification reaction. In addition, the presence of the new supplementary groups on cyclodextrin could effect on the aggregation behaviour of this new cyclodextrin derivative as demonstrated by dynamic light scattering and AFM.     

The effect of type II and type IV resistant starch on the hydrolysis of maize and wheat gelatinised starch catalysed by pancreatic α‐amylase

The effects of resistant starch on human metabolism are considered to be beneficial because they decrease postprandial glycaemia following ingestion of starch‐rich foods. Using type II and IV resistant starches, we found a direct competitive inhibitory effect on porcine pancreatic α‐amylase action above 0.25 g/100 g affecting catalytic efficiency when wheat and maize starches were used as substrates. Because resistant starches do not gelatinise and no modifications of gelatinisation parameters were observed, we concluded that the inhibitory action of these types of polymer seem to be a consequence of impaired diffusion of enzyme, substrate or products because of an increase in branches in the two types of resistant starches used. Thus, the effects of type II and type IV resistant starches in lowering postprandial glycaemia not only involve modification of gut physiology, but also include direct inhibition of the first stage in the biochemical degradation of starch.