Mechanistic insights into the supramolecular structure and physicochemical properties of twin-screw extruded high amylose corn starch with different amylose content by improved electron beam irradiation

The influence of improvement via electron beam (EB) of twin-screw extruded (TSE) high amylose corn starch on its multiscale structure and physicochemical properties was assessed. The granular integrity of TSE was lost and the crystal type changed. TSE increased amylose content, A-chain content, rapidly digestible starch content and slowly digestible starch content, but decreased crystallinity, molecular weight and resistant starch content. These structural changes made TSE samples more susceptible to subsequent EB-irradiation. The molecular weight and long chain of amylopectin in TSE-sample were decreased by EB-irradiation. Amylose content, crystallinity and short-range order were reduced by EB-irradiation. These structural alterations facilitated the enhancement of TSE properties. The TSE-EB sample had better solubility, anti-digestive properties, lower swelling power and apparent viscosity. The combination of TSE and EB is an effective method to improve starch's structure and properties and this modified starch could be implemented to tailor starch to the desired food applications.     

Effects of sodium dodecyl sulphate and sonication treatment on physicochemical properties of starch

Effects of sodium dodecyl sulphate (SDS) and sonication treatment on physicochemical properties of starch were studied on four types of starch, namely, corn, potato, mung bean, and sago. The SDS and sonication treatments caused a significant reduction of protein content for all the starches. The SDS treatment did not cause apparent damage on granular structure but sonication appeared to induce changes such as rough surface and fine fissures on starch granules. The combination of SDS and sonication increased amylose content for all starches. This could be attributed to the removal of surface protein by SDS and structural weakening by sonication which facilitated amylose leaching from swollen starch granule. The X-ray pattern for all starches remained unchanged after SDS treatment, suggesting no complexation of amylose–SDS had occurred. Combined SDS-sonication treatment increased swelling and solubility of corn, mung bean, and potato starch. The treated starches showed significant increase in peak viscosity with reduction in pasting temperature, except for potato starch. Results of the present study indicate the possibilities of exploring SDS and sonication treatments for starch modifications.     

Effect of Longer Heating Time on Depolymerization of Low Moisturized Starches

Low moisturized potato, sweet potato, corn and wheat starches were treated with a flow tester under heated and heated-sheared conditions. The starches depolymerized into lower molecule by longer heating time at 150°C. With an increase in heating time, the cold water solubility of starches increased and the degree of depolymerization progressed. Comparing heated treatment with longer heating time and heated-sheared treatment, 60—120min heating was necessary for heated specimens to obtain similar cold water solubility and degree of depolymerization of heated-sheared specimens. These results conducted that heated-sheared treatment strongly promoted the depolymerization of low moist starches under high temperature as compared with heated treatment only. From the results of λ_max of iodine-polysaccharide complex, there was almost same molecular state between heated for longer time and heated-sheared treatment. Both amylose and amylopectin depolymerized into lower molecule by both treatments.     

冻融处理对淀粉膜结构、热稳定性、机械性能及物理性质的影响

本实验分别以天然马铃薯淀粉（potato starch,PS）、改性马铃薯淀粉（包括羟丙基二淀粉磷酸酯（hydroxypropyl distarch phosphate,HDP）、醋酸淀粉（acetate starch,AS）和氧化淀粉（oxidized starch,OS））为基材,通过流延法制备可食用淀粉膜,考察冻融处理对膜物理性质、机械性能、阻隔性能、微观结构和热稳定性的影响。X射线衍射结果表明,马铃薯来源的淀粉颗粒具有典型的B型晶体结构,在成膜过程中淀粉结晶度降低,冻融处理后淀粉膜晶体峰强度明显减弱。扫描电子显微镜观察结果显示,冻融处理破坏了淀粉膜的微观结构,其中PS膜上出现明显裂纹,AS膜上出现蜂窝和层状结构,而HDP和OS淀粉膜具有更完整的形态。热重分析结果表明,随着温度的升高,淀粉膜的热重曲线出现4 个质量损失阶段,分别对应水分散失、甘油挥发、淀粉解聚及淀粉分解,而冻融处理对膜热稳定性影响较小。常温条件下,PS膜具有最佳的机械性能,其拉伸强度为2.29 MPa,断裂伸长率为68.82%。在3 个冻融循环后,淀粉膜的拉伸强度至少增加了2 倍,断裂伸长率普遍降低,而溶解度和水蒸气透过率仅有轻微变化。综合考虑不同淀粉膜微观结构、机械性能、水蒸气透过率及水溶性,HDP膜表现出更好的冻融稳定性,可应用于冷冻低水分食品的保藏。     

热处理改性淀粉的理化性质、结构和消化特性的研究进展（网络首发、推荐阅读）

热处理改性淀粉具有操作简单、污染少、产品安全性高的优点,是最常用的淀粉物理改性方法。主要总结了干热处理、湿热处理和韧化处理对淀粉理化性质、结构性质和消化性质的影响,也总结了添加亲水胶体辅助热处理和多种热处理方法联合处理对淀粉理化性质及消化性质的影响。研究发现热处理改性能够提高淀粉热稳定性和抗消化能力。热处理改性对淀粉性质的影响与热处理改性方式、淀粉种类和来源有关,其中湿热处理和韧化处理过程水分含量较高,能使淀粉的溶胀力和溶解度发生显著改变。三种热处理方法均能够改变淀粉相对结晶度,湿热处理还能改变淀粉的结晶晶型。除韧化处理外,干热处理和湿热处理均能改变淀粉颗粒结构。添加亲水胶体辅助热处理或热处理方法联合处理能增强热处理改性对淀粉理化性质和消化性质的影响。这为热处理改性淀粉的进一步研究及应用提供参考。     

Composition,structure and physicochemical properties of three coloured potato starches

Composition, structure and physicochemical properties of starch from red‐ and purple‐fleshed potatoes were investigated and compared to those of typical yellow‐fleshed potatoes. The starch from yellow has highest amylose (25.23%) content, following by purple (23.30%) and red (20.26%). The growth ring of the three starches differed, but granule morphology was largely similar. Each potato starch exhibited B‐type crystalline patterns, with crystallinity ranging from 20.33% to 22.25%. The molecular weights and z‐average radius of gyration exhibited significant difference among the three starch samples. The branch chain length distribution showed that purple potato starch had highest population of A chains and lowest population of B1 chains. Moreover, the pasting properties of the three samples differed remarkably. The purple (90.92%) and red (86.41%) potato starches presented extremely good light transmittance compared with the yellow potato starch (34.03%). Dynamic rheological analysis showed that all samples possessed a weak elastic gel‐like structure.     

流化床气流超微粉碎对马铃薯淀粉结构及性质的影响

为研究流化床气流超微粉碎对淀粉结构及性质的影响,以马铃薯淀粉为原料,采用激光粒度分析仪、扫描电子显微镜、光电子能谱仪、同步热分析仪、流变仪等多种仪器及分析手段,考察气流粉碎对马铃薯淀粉颗粒大小及形貌、表面基团、热稳定性、流变特性、溶解度、膨胀度及透明度等结构及性质的影响。结果表明:马铃薯原淀粉经气流粉碎微细化处理后,平均粒径（D₅₀）减小至13.59±0.04 μm;X射线光电子能谱（XPS）的谱图中没有出现新元素峰位,淀粉颗粒表面没有引入新元素;直链淀粉含量增加,支链淀粉分子链变短,溶解度、膨胀度和淀粉糊透明度增加;粘性阻力减小,表观粘度降低;淀粉分子氢键及分子链均发生断裂,凝沉性下降,该研究为马铃薯淀粉的深度加工与应用提供了理论依据及技术支撑。     

氧化和湿热处理对马铃薯淀粉功能特性的影响

对原料淀粉进行改性处理可以改善其功能特性,使其更好的在食品中应用。利用氧化和湿热处理的方法改性马铃薯淀粉,并通过对其微观结构、膨润能力和溶解度、糊化特性和凝胶强度的测定,对改性马铃薯淀粉样品的功能特性进行了评价。偏光显微镜和扫描电镜结果显示,氧化作用主要发生在马铃薯淀粉颗粒的非结晶区域。氧化和湿热处理均使马铃薯淀粉的糊化温度升高、粘度降低,且两种处理方法均提高了马铃薯淀粉的热稳定性。凝胶强度测定结果显示,0.2%氧化剂浓度处理的马铃薯淀粉凝胶强度显著提高(p<0.05)。     

微波对马铃薯淀粉性质的影响

研究微波辐射前后马铃薯淀粉物化性质的变化。采用微波对30%水分含量的马铃薯淀粉进行处理。结果表明:微波淀粉颗粒表面出现凹坑,降低了膨胀度和溶解度、冻溶稳定性。主要X-射线衍射峰的强度增大,晶型由B型转为A型,马铃薯淀粉经处理后糊化起始温度升高、粘度降低,粘度曲线由A型变为C型。试验表:在淀粉颗粒内无定形区和结晶区的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的降解。     

超声波处理对马铃薯全粉理化性质和消化特性的影响

以马铃薯全粉为原料,研究超声处理对马铃薯全粉理化性质和消化特性的影响。结果表明:超声处理使得马铃薯全粉的结晶度增大,晶体结构明显改变,溶解度、膨胀度、吸油性、崩解值、糊化温度和消化特性显著降低。随着超声波处理时间的延长,马铃薯全粉的结晶度、峰值黏度、谷值黏度和最终黏度先升高后降低。随着超声波处理时间的延长,快消化淀粉(RDS)含量降低,慢消化淀粉(SDS)和抗性淀粉(RS)含量升高。研究表明,超声处理显著影响马铃薯全粉的理化性质和消化特性(P0.05)。     

Granular Properties of Different Starch Phosphate Monoesters

Different starch types (corn, rice, and potato starch, corn amylose and corn amylopectin) were phosphorylated by reaction with a mixture of mono and disodium phosphate at different molar ratios (mol phosphate/mol anhydrous glucose) under heat and vacuum. The starch granules of the modified and the native starches were microscopically examined for their sizes and morphology. The correlation between the variation in granular size of the modified starches with the extent of phosphorylation and some other physicochemical properties was studied. The granular size was generally increased while the iodine absorption capacity was decreased by phosphorylation. There were strong correlations between the variation in the starch granular size in dependence on phosphorylation and the corresponding changes in some physicochemical parameter of starch, e.g. solubility, swelling and paste clarity. This relationship was most evident in the case of phosphorylated corn amylopectin. Starch granular size can be taken as a quick indicator of the physicochemical properties of the native and modified starches.     

Development of oxidised and heat-moisture treated potato starch film

This study investigated the effects of sodium hypochlorite oxidation and a heat-moisture treatment of potato starch on the physicochemical, pasting and textural properties of potato starches in addition to the water vapour permeability (WVP) and mechanical properties of potato starch films produced from these starches. The carbonyl contents, carboxyl contents, swelling power, solubility, pasting properties and gel texture of the native, oxidised and heat-moisture treated (HMT) starches were evaluated. The films made of native, oxidised and HMT starches were characterised by thickness, water solubility, colour, opacity, mechanical properties and WVP. The oxidised and HMT starches had lower viscosity and swelling power compared to the native starch. The films produced from oxidised potato starch had decreased solubility, elongation and WVP values in addition to increased tensile strength compared to the native starch films. The HMT starch increased the tensile strength and WVP of the starch films compared to the native starch.     

Effect of acid treatment on the physicochemical and structural characteristics of starches from different botanical sources

Starch and starch derivatives (maltodextrins) are used as encapsulating materials. Starch for use as encapsulating material could be subjected to mild acid treatment. However, the granule size and organization of starch components (AM and AP) play an important role in the acid treatment. The aim of this research was to produce modified starch that might be used as encapsulate material, applying moderate acid‐treatment with 3 N sulphuric acid in a ratio 1:5 w/v for 3 h at 60°C, in starches from different granule size, evaluating their morphological, physicochemical, and structural features. Acid treatment has an effect in the AM content and the outcome was higher in starch with larger granule size. Bimodal granule size distribution was found in acid‐treated rice and maize starches. Erosion and exo‐corrosion were observed in acid‐treated starches with SEM. The XRD pattern did not change with the acid treatment, the native and acid‐treated samples showed similar crystallinity values, except rice starch. The branching degree was higher for modified potato starch, showing higher branching points, modified starches had shorter chains with increased A‐chains, and decreased B3+ chains, and the effect was higher in cereal starches; modified starches had a higher degree of retrogradation and they did not show pasting properties. The internal organization given by the granule size is an important parameter in the acid treatment of starches as it affected their physicochemical and structural features, and in the end, their functionality as encapsulate agent.     

葡萄籽原花青素对不同淀粉理化性质影响的研究

以绿豆淀粉、小麦淀粉和土豆淀粉为原料,研究了葡萄籽原花青素的添加(1%、2%、3%、4%),对不同淀粉理化性质(溶解度、膨胀度、耐酶解淀粉含量、硬度和冻融稳定性)的影响。结果表明:葡萄籽原花青素的添加使三种淀粉的膨胀度均有所升高,硬度显著降低,耐酶解淀粉的含量明显增多。在添加量3%时,土豆淀粉的冻融稳定性显著提高。此外,原花青素的添加使绿豆淀粉的溶解度提高,土豆淀粉的溶解度降低,但对小麦淀粉的溶解度影响不显著。     

Comparative susceptibilities of sago,potato and corn starches to alkali treatment

The effects of steeping starch (sago, corn, and potato), in 0.025 M of sodium hydroxide for 0, 15, and 30 days at 30 °C, on its granular structure and other physicochemical properties were investigated. Changes in the morphology of starch granules indicated that the alkaline solution affected the granular structure of the starch. Pasting studies showed that the peak viscosity, breakdown, and setback of sago and potato starch decreased significantly, whereas that of corn starch increased significantly, when steeping time was prolonged. Swelling power increased significantly for treated potato and corn starches, but it decreased for sago starch. The amylose content of all alkali-treated starches also decreased significantly after treatment. Onset and peak temperatures of gelatinization (as analyzed with a differential scanning calorimeter) increased significantly, but the enthalpy decreased, for both gelatinization and retrogradation. The results showed that the physicochemical properties of starch of various botanical origins were affected to variable degrees when it was treated with alkaline solution.     

Influence of prior acid treatment on physicochemical and structural properties of acetylated sorghum starch

Influence of prior acid treatment on acetylation of starch isolated from an Indian sorghum cultivar was investigated. The starch was acid thinned (AT) using 0.1, 0.5, and 1 M HCl for 1.5 h and then acetylated (Ac) with acetic anhydride (8% w/w). The acid thinning and subsequent acetylation appeared to reduce the percentage acetylation as indicated by degree of substitution. Ac‐AT starches exhibited significantly different physicochemical, thermal, pasting, and gel textural properties from those of AT and Ac starches. Starches after dual modification showed higher solubility, lower AM content, gelatinization temperatures, retrogradation, peak viscosity, and gel hardness than native starch. Enthalpy and range of gelatinization were observed to be higher in dual modified starches than native starch. However, no significant changes in granule morphology or crystalline pattern of Ac‐AT starches were observed compared with native starch.     

Pasting,Thermal, Hydration,and Functional Properties of Annealed and Heat-Moisture Treated Starch of Sword Bean (Canavalia gladiata)

The effects of annealing (ANN) and heat-moisture treatments (HMT) on the physicochemical and functional properties of Sword bean starches were investigated. The pasting properties differ significantly among the starches, with peak viscosity ranging from 399.17 RVU to 438.33 RVU; however, all the starches exhibited ‘Type C’ class with restricted swelling. The HMT starches had the highest gelatinization temperature, while change in enthalpy of gelatinization, ΔH_gel of the native starch, was higher (13.82 J/g) than that of the modified starches (1.39–6.74 J/g). The solubility and swelling power of all the starches increased as the temperature increased. The oil and water absorption capacity of the starches ranges between 3.24–3.91 g/g and 2.42–3.35 g/g, respectively. HMT (at 25 and 30% moisture level) changes the X-ray diffraction pattern of the starch from Type ‘B’ to Type ‘C’. The Scanning electron micrograph results revealed the starch granules with smooth ellipsoids and indentation in their centre, hydrothermal modification showed little effect on the morphology and size of the granules. Hydrothermal modification improved the physicochemical and functional properties of the starch without destroying the granule of the starch.     

超高压处理对槟榔芋淀粉理化性质的影响

以槟榔芋淀粉为原料,采用超高压技术对淀粉进行改性处理,研究不同压力处理对其理化性质的影响.结果表明:随着压力的增大,槟榔芋淀粉的溶解度、膨胀度呈先减小后增大的趋势,但是均显著低于原淀粉;超高压处理可以显著增大槟榔芋淀粉的透光率;经200 MPa压力处理后,其冻融稳定性有明显改善.经300 MPa压力处理后,槟榔芋淀粉凝胶的硬度、咀嚼性和胶黏性都显著增加,但弹性和凝聚性变化不显著.RVA测定结果表明:淀粉糊的峰值黏度随处理压力的增大而显著增大;改性后槟榔芋淀粉的崩解值略高于原淀粉,而回生值变化不显著;200 MPa压力处理可降低槟榔芋淀粉的糊化温度.研究表明,一定程度的高压处理可以达到改善槟榔芋淀粉理化性质的目的.     

碾轧处理对乙酰化淀粉品质的影响及作用机理

为研究碾轧处理对乙酰化淀粉品质的影响及其作用机理,本文以甘薯淀粉为原料,研究不同碾轧处理时间(0、2、5、7、18 h)对乙酰化甘薯淀粉的品质、结构和理化性质的影响,采用机械力化学相关理论分析碾轧处理对乙酰化甘薯淀粉品质影响的作用机理。结果表明:碾轧处理2和7 h后,乙酰化甘薯淀粉的反应效率分别增加到74.45%和75.40%,其它品质(溶解度、膨胀力和峰值黏度)也显著提高。甘薯淀粉在碾轧处理2 h后,与原淀粉相比,结晶度降低且位于17.8 °处的衍射峰消失,T₂值增大,糊化焓和峰值黏度减小,热稳定性减弱;碾轧处理5 h后,溶解度、膨胀力和峰值黏度都减小,但淀粉的热稳定性增大;与处理2 h后相比,结晶度变大,T_2,2值消失;碾轧处理7~18 h后,结晶度、糊化焓和热稳定性显著降低,T_2,1值增大,碾轧处理18 h后淀粉分子晶体区域的双螺旋结构呈短程有序方式排列。这些变化表明碾轧处理可对甘薯淀粉颗粒产生显著的机械力化学效应。随着碾轧处理时间的增加,淀粉颗粒内部依次经历了受力、聚集和团聚阶段。机械力化学对淀粉颗粒作用的三个阶段具有不同的影响机制,为今后研究制备高品质变性淀粉先进装备奠定一定的理论基础。     

酶促合成肉豆蔻酸淀粉酯的性质及结构表征

为提高淀粉的反应活性,采用氢氧化钠尿素法对马铃薯原淀粉进行处理,以处理后的马铃薯淀粉和肉豆蔻酸为原料,Novozyme 435为催化剂,在无溶剂体系中制备了取代度为0.018~0.065的肉豆蔻酸淀粉酯,并对其部分理化性质进行研究。结果表明:与原淀粉相比,预处理淀粉溶解度和透明度显著增加(P0.05),其膨胀度、冻融稳定性、乳化性和乳化稳定性均显著降低(P0.05)。同时,肉豆蔻酸淀粉酯的性质与其取代度密切相关,与原淀粉相比,随着取代度的增加,酯化淀粉冻融稳定性、乳化性和乳化稳定性随之升高,而其溶解度、膨胀度和透明度随之下降。扫描电子显微镜(SEM)、傅里叶红外光谱分析(FTIR)、疏水性测定对预处理淀粉及不同取代度的肉豆蔻酸淀粉酯进行观察、测定、分析,结果表明,淀粉颗粒结构被破坏,酯化淀粉具有较好的疏水性,FTIR验证了预处理淀粉及酯化淀粉的生成。