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.     

Physicochemical properties of potato and cassava starches and their mutants in relation to their structural properties

Physicochemical properties [swelling power (SP), pasting behaviour and retrogradation] of five wild type (wt), five amylose free (amf), four high-amylose (ha) potato starches (ps) and one wt and amf cassava starch (cs) were investigated. While swelling of wtps occurred in two phases, amfps showed a very fast swelling and no gel of swollen granules was observed at higher temperatures (>90 °C). Haps underwent only restricted swelling. SP of cassava starches were lower than those of potato starches. Wtps leached mainly amylose (AM) during heating at low temperatures. Molecules of higher molecular weight (MW) leached out at higher temperatures. Longer amylopectin (AP) chains [degree of polymerisation (DP) > 18] inhibited swelling while short chains (DP < 14) favoured swelling. Starch pasting behaviour of 5.0 and 8.0% starch suspensions was studied using Rapid Visco Analyser (RVA). For 5.0% suspensions, increased levels of high-MW AP and decreased levels of AM molecules led to higher peak viscosity. Longer AP chains (DP > 18) depressed peak viscosity, while short chains (DP < 14) increased peak viscosity for both concentrations. At 8.0%, peak viscosity increased with starch granule size. After 1 day of storage of gelatinised starch suspensions, wtps and especially amfps showed only limited AP retrogradation. In contrast, the high enthalpies of retrograded AP (ΔH_retro) and peak and conclusion temperatures of retrogradation (T_p,retro and T_c,retro) of haps suggested partial cocrystallisation between AM and AP. Chains with DP 18–25 seemed to be more liable to AP retrogradation. Wtcs and amfcs did not retrograde at room temperature.     

大米淀粉结构与特性研究进展

大米淀粉是主要的谷物淀粉之一,具有一些独特的结构及物化特征。本文主要从淀粉颗粒结构、生长环结构、Blocklets小体、层状结构、结晶结构及链结构等多尺度结构层次和凝胶化、糊化、回生及消化等特性方面,对大米淀粉结构和物化特性进行了全面的综述,并阐述了大米淀粉不同层级结构对其特性的影响,同时介绍了大米淀粉的主要制备方法与组成成分及其对大米淀粉特性的影响,以期为大米淀粉的研究与开发提供借鉴。     

Physicochemical properties of starches obtained from Polish potato cultivars

Selected physicochemical, thermal, and rheological properties of starches isolated from new Polish potato varieties were determined. The starches contained 25.7–30.0 g/100 g d.m. of amylose and 59.5–90.2 mg/100 g d.m. of phosphorus. Gelatinization temperatures were 62.6–64.0, 68.9–69.9, and 73.6–77.0°C for T_O, T_P, and T_E, respectively, whilst enthalpy of gelatinization amounted to 11.1–15.3 J/g. The retrogradation degree of starch was from 52.90 to 78.53%. Pasting curves showed significant differences between the starches. Peak viscosity and final viscosity ranges were 2035–4458 and 1931–2985 mPa · s, respectively. Starch pastes exhibited non‐Newtonian, shear thinning, and thixotropic behavior. After cooling they demonstrated diversified viscoelastic properties, however, all of them were classified as weak gels. Significant linear correlations among selected rheological parameters and amylose and phosphorus content were found. Results of principal component analysis demonstrated an ability to differentiate the starches isolated from different potato varieties.     

Effect of heat-moisture treatment on the structure and physicochemical properties of legume starches

Native green arrow pea (GAP), eston lentil (EL), othello pinto bean (PB), black bean (BB) and express field pea (FP) starches were heat-treated at 100 °C for 16 h at a moisture content of 30%. The heat treatment did not change granule size and shape. The surfaces of GAP and EL were modified after heat treatment. Heat treatment decreased amylose leaching (GAP > FP˜EL > BB˜PB) and the swelling factor (EL ˜ FP > GAP > BB ˜ PB). The X-ray diffraction intensities increased in GAP starch, but decreased in the other starches (FP > BB > PB > EL). However, the X-ray pattern of all starches remained unchanged after heat treatment. Differential scanning calorimetry of the heat-treated samples showed a broadening of the gelatinization temperature range and a shifting of the endothermal transition towards a higher temperature (EL-EP>BB-PB). However, the gelatinization enthalpy (ΔH) of all starches remained unchanged. The susceptibility towards hydrolysis by porcine pancreatic -amylase increased on heat treatment (BB > EL > FP > PB > GAP). The action of -amylase on the starches decreased ΔH in EL and FP. However, ΔH decreased only marginally in PB and BB. Acid hydrolysis (2.2 N HCl) increased on heat treatment (BB>FP˜EL˜PB>GAP). The results showed that bonding forces within the amorphous regions of the granule, crystallite orientation and the granule surface (in GAP and EL) are altered during heat treatment, the magnitude of these changes being dependent upon the starch source.     

紫马铃薯淀粉的理化性质研究

紫马铃薯具有较高的营养价值,在食品工业中将有重要而广泛的应用前景。淀粉是紫马铃薯的主要成分,其理化性质对紫马铃薯制品有重要的影响。以\     

Physico-chemical properties of potato starches

Starches were isolated and characterised from 10 potato cultivars grown under the same conditions (with a commercial starch for reference). The chemical composition revealed some differences amongst the starches with protein ranging from 0.30% to 0.34%, amylose 25.2% to 29.1% and phosphorus 52.6–66.2 mg 100 g⁻¹. High performance size-exclusion chromatography (HPSEC) fractionation of isoamylase debranched amylopectin showed that the amylopectin molecules were less branched and consisted of more B1, but less A-chains, than cereal starches. Gelatinisation onset (T_o), peak (T_p) and conclusion (T_c) temperatures of the native potato starches ranged from 58.7 to 62.5 °C, 62.5 to 66.1 °C and 68.7 to 72.3 °C, respectively, whilst the gelatinisation enthalpies ranged from 15.1 to 18.4 J g⁻¹. The gelatinisation temperatures of the starches increased in common with the amounts of short and intermediate sized amylopectin chains. The ¹³C magic angle spinning nuclear magnetic resonance (¹³C CP-MAS NMR) and wide angle X-ray diffraction (XRD) data (30.6% ± 0.22% crystallinity on average) showed little variance amongst the samples. Particle sizing results, however, revealed more variance (20.6–30.9 μm mean diameter). Overall, these data reveal the subtleties of cultivar specific variation against a background of constant environmental conditions.     

Molecular structure and physicochemical properties of Hylon V and Hylon VII starches illuminated with linearly polarised visible light

Aqueous suspensions (30 g/100 g) of Hylon V and Hylon VII high amylose corn starches were illuminated with linearly polarized visible light for 5, 15, 25 and 50 h. For each native and illuminated starch sample, weight average molecular weight, M_w, and hydrodynamic radius, R_g, of starch polysaccharide molecules were measured by high pressure size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). Additionally, X-ray diffraction patterns, intrinsic viscosity, kinetic of alpha-amylolysis together with iodine binding properties and distribution of amylopectin structural units were established for each starch sample. Changes in molecular weight M_w of starch polysaccharide chains eluted under whole polysaccharide peaks and values of intrinsic viscosity of corresponding starch samples observed in the course of illumination indicated that illumination of both starches studied, with linearly polarized visible light (LPVL), induced first depolymerysation followed by repolymerisation reaction of starch polysaccharide chains. Illumination induced rearrangements of the molecular structure of polysaccharide chains of illuminated Hylon V and Hylon VII starches led to significant changes of their physicochemical properties as compared with native starches.     

豌豆淀粉与马铃薯淀粉、玉米淀粉理化性质比较

通过对豌豆淀粉、马铃薯淀粉和玉米淀粉的基本组成、颗粒形态、凝沉性、糊化特性、透明度及抗性淀粉含量的测定与比较表明:豌豆淀粉中直链淀粉和蛋白质的含量较高,但其颗粒直径小于马铃薯淀粉;与马铃薯淀粉和玉米淀粉相比,豌豆淀粉易于回生,但糊稳定性较好;豌豆淀粉糊的透明度低于马铃薯淀粉,但其淀粉组成中慢消化淀粉含量高于马铃薯淀粉和玉米淀粉。      

Effect of debranching and storage condition on crystallinity and functional properties of cassava and potato starches

Debranching starch by pullulanase is considered to improve the RS content of starch which is widely used to produce the starch‐based foods with high‐health benefit impacts. In this study, the cassava and potato starches were debranched by pullulanase, followed by an autoclave treatment and storage at −18°C, 4°C, or 25°C to investigate their crystallinity and functional properties. After debranching, the potato starch contained significantly higher CL (35.4 glucose units) than did the cassava starch (32.4 glucose units). The debranched cassava and potato starches after retrogradation at the storage temperatures had a typical B‐type crystalline structure although the native cassava and potato starches exhibited the different crystalline forms (A‐ and B‐type, respectively). The RS contents of the debranched cassava and potato starches significantly improved with higher RS content of the debranched potato starch than that of the debranched cassava starch at the same storage condition. The storage temperature significantly affected the RS formation of the debranched starches with the highest RS content at storage temperature of −18°C (35 and 48% for the debranched cassava and potato starches, respectively). The debranched starches had significantly lower viscosities and paste clarities but higher solubilities than did the native starches. As a result, the debranched cassava and potato starches can be considered for use not only in functional foods with enhanced health benefits but also in pharmaceutical and cosmetic industries.     

3种栗属坚果淀粉的结构及其理化特性

以我国南北方种植的3种栗属坚果(板栗、锥栗和日本栗)为原料提取淀粉,通过扫描电镜(SEM)、X射线衍射仪(XRD)、差示扫描量热仪(DSC)、快速黏度仪(RVA)等仪器和方法,研究14个品种淀粉的颗粒结构和理化特性的差异,并对其进行相关性分析。结果表明:栗属坚果的直链淀粉含量差异显著,淀粉颗粒形态较为复杂,颗粒表面光滑完整;淀粉均属于C型晶体,结晶度为20.43%～25.63%,淀粉的冻融稳定性好。不同品种淀粉的颗粒结构和理化特性之间存在多种相关性,说明直链淀粉含量和结晶结构影响淀粉的理化性质。     

盐对不同直链含量玉米淀粉理化特性及流变学特性的影响

分析了盐对不同直链含量玉米淀粉的理化特性及流变学特性的影响。结果表明,盐抑制了淀粉颗粒的膨胀,盐浓度越大,抑制作用越强。盐质量浓度为0 g/100 mL的蜡质淀粉和普通淀粉膨胀势在65℃到75℃迅速增加,2.0 g/100 mL时膨胀势在75℃到85℃迅速增加且幅度最小。蜡质淀粉和普通淀粉DSC图谱呈G峰和M2峰,高直链淀粉呈G峰。盐提高了凝胶化起始温度,蜡质淀粉从50.1℃增加到90.2℃,普通淀粉从56.6℃增加到99.6℃,高直链淀粉从98.8℃增加到105.7℃。盐也抑制了淀粉的糊化进程,盐浓度越大,糊化温度越高。普通淀粉的储存模量G',损耗模量G"和表观黏度η大于蜡质淀粉。普通淀粉和蜡质淀粉在低盐浓度(0.6g/100 mL)下的G'、G"和η值均大于高盐浓度(2.0 g/100 mL)。     

槟榔芋淀粉与其球磨酯化淀粉理化性质比较

以槟榔芋原淀粉为原料,采用球磨结合辛烯基琥珀酸(OSA)酯化方法制得复合改性淀粉,对其理化性质进行研究,并与原淀粉、酯化淀粉和球磨淀粉进行比较。结果表明:球磨淀粉的溶解度、膨润力和透明度均显著提高(P0.05),尤其是冷水溶解度,但其抗凝沉性、冻融稳定性和表观黏度却降低;酯化淀粉和复合改性淀粉的溶解度、膨润力、透明度、抗凝沉性、冻融稳定性和表观黏度均明显提高,由此可见槟榔芋原淀粉和球磨淀粉经OSA酯化改性后品质均得到明显改善,复合改性淀粉的表观黏度增加尤为明显,说明其具有更好的增稠性能。     

Amylopectin structure of heat–moisture treated starches

The effects of heat–moisture treatment (HMT; moisture content of 25%, at 100°C for 24 h) on starch chain distribution and unit chain distribution of amylopectin in normal rice, waxy rice, normal corn, waxy corn, normal potato, and waxy potato starches were investigated. After HMT, starch chain distribution (amylose and amylopectin responses) of waxy corn and potato starches were identical to those of untreated starches, whereas the chromatographic response of waxy rice starch showed a slight decrease, but with a slight increase in peak tailing. This result indicated that HMT had no (or very limited) effect on the degradation of amylopectins. Analysis of unit chain distribution of amylopectins revealed that waxy characteristics affected the molecular structure of amylopectin in untreated starches, i.e., the CL of normal‐type starches was greater than that of waxy‐type starches. After HMT, the CL and unit chain distribution of all starches were no different than those of untreated starches. The results implied that changes in the physico‐chemical properties of HMT starches would be due to other phenomena rather than the degradation of amylopectin molecular structure. However, the thermal degradation of amylopectin molecules of waxy starches could occur by HMT at higher treatment temperatures (120 and 140°C).     

紫薯渣淀粉理化性质的研究

以制得的紫薯淀粉为原料,研究了紫薯淀粉的化学组分、颗粒表面结构、结晶结构、凝胶质构、热力学性质和流变学特性,并与马铃薯淀粉、玉米淀粉和甘薯淀粉进行比较。结果显示：干基紫薯淀粉含量为98.78%,直链淀粉含量为19.74%;其淀粉颗粒平均粒径为17 μm,属中粒淀粉,晶型为C型;淀粉凝胶弹性和咀嚼性高,硬度适中,为3.095× 102 g,粘着性适中,为24.72 g.s;糊化温度范围为61.5 ℃到78.0 ℃,峰值温度为72.6 ℃;紫薯淀粉糊为有屈服应力的非牛顿型流体。     

超声波辅助韧化改性甘薯淀粉的结构及理化特性

为研究超声波辅助韧化对甘薯淀粉特性的影响,在其韧化处理不同阶段施加超声波,并对其表观直链淀粉含量、相对分子质量、支链淀粉链长分布、淀粉颗粒形态、结晶结构、糊化、流变、凝胶性质等理化特性进行表征。结果表明,在韧化处理中施加超声波对支链淀粉侧链分布和淀粉颗粒形态特征无显著影响;超声波辅助韧化在一定程度上改变了甘薯淀粉的结晶结构,韧化中间阶段施加超声波使其相对结晶度从31.98%减少至25.71%;与单独韧化相比,超声波辅助韧化使甘薯淀粉具有更高的回升值（1220 cp）和更低的崩解值（1594 cp）,同时使甘薯淀粉凝胶的G″与G′值升高,大幅提高了甘薯淀粉凝胶的弹性和黏性;超声波辅助韧化使甘薯淀粉的凝胶硬度、胶黏性和咀嚼性增加。     

支链聚合度对菠萝蜜种子淀粉理化特性的影响

从菠萝蜜种子淀粉(jackfruit seed starch,JFSS)分离直链淀粉和支链淀粉,将相同直链淀粉(50%)混合5种不同支链淀粉,制备具有不同支链聚合度的JFSS(M1′、M5′、M6′、M11′和BD′),探究支链聚合度对JFSS理化特性的影响。结果显示:M1′具有最低的支链聚合度(189 506),BD′具有最高的支链聚合度(431 481)。随着支链聚合度增加,5种JFSS样品的脱水收缩、凝胶化焓、峰值黏度、谷值黏度、崩解值、最终黏度、回生值、相对结晶度和吸光度比分别从72.87%、15.59J/g、4 755cP、3 548cP、1 207cP、5 751cP、2 203cP、33.22%、1.56(M1′)降低至66.79%、13.84J/g、2 717cP、1 971cP、746cP、3 158cP、1 187cP、27.94%、1.45(BD′)。然而转变温度和糊化温度分别从48.19,60.39,75.32,77.55℃(M1′)升高到52.39,64.54,78.47,81.60℃(BD′)。冻融稳定性、热特性、结晶结构、短程分子序列的结果表明,支链聚合度是影响淀粉理化特性的重要结构因素。     

白芸豆淀粉与小利马豆淀粉理化性质的比较研究

本实验以白芸豆和小利马豆为原料,采用碱法提取淀粉,对白芸豆淀粉和小利马豆淀粉的理化特性进行分析研究。结果表明,白芸豆和小利马豆的淀粉颗粒均呈表面光滑、无棱角及裂痕的特征,且2种淀粉的微晶结构均为A型;2种豆类淀粉的溶解度和膨胀度均随温度的升高而增加。小利马豆淀粉和白芸豆淀粉在冻融稳定性、透明度和成糊特性等方面存在显著差异,小利马豆淀粉的膨胀度、溶解度及淀粉糊的冻融稳定性和透明度更好,而白芸豆淀粉呈现起糊温度、峰值黏度、破损值和回生值较低的成糊特性,易成糊、抗剪切。