Structural characterizations and digestibility of debranched high-amylose maize starch complexed with lauric acid

Structural characterizations and digestibility of debranched high-amylose maize starch complexed with lauric acid (LA) were studied. The cooked starch was debranched by using pullulanase and then complexed. Light microscopy showed that the lipids complexed starches had irregularly-shaped particles with strong birefringence. Gel-permeation chromatograms revealed that amylopectin degraded to smaller molecules during increasing debranching time, and the debranch reaction was completed at 12 h. Debranching pretreatment and prolonged debranching time (from 2 h to 24 h) could improve the formation of starch lipids complex. X-ray diffraction pattern of the amylose–lipid complexes changed from V-type to a mixture of B- and V-type polymorphs and relative crystallinity increased as the debranching time increased from 0 to 24 h. In DSC thermograms, complexes from debranched starch displayed three separated endotherms: the melting of the free lauric acid, starch–lipid complexes and retrograded amylose, respectively. The melting temperature and enthalpy changes of starch–lipid complex were gradually enhanced with the increasing of debranching time. However, no significant enthalpy changes were observed from retrograded amylose during the starch–lipid complex formation. Rapidly digestible starch (RDS) content decreased and resistant starch (RS) content increased with the increasing of debranching time, while the highest slowly digestible starch (SDS) content was founded at less debranching time of 2 h. The crystalline structures with dense aggregation of helices from amylose-LA complex and retrograded amylose could be RS, while SDS mostly consisted of imperfect packing of helices between amylopectin residue and amylose or LA.     

Preparation and properties of RS III from waxy maize starch with pullulanase

Waxy maize starch was treated by pullulanase debranching and retrogradation at room temperature to produce resistant starch (RS). Physicochemical properties, crystalline structure and in-vitro digestibility of starch samples with different RS content were investigated. Compared with native starch, apparent amylose content of RS products increased. Based on Gel Permeation Chromatography (GPC) the Molecular Weight Distribution (MWD) of resistant starches significantly changed. Scanning Electron Microscopy (SEM) showed that upon pullulanase debranching and retrogradation treatment the granular structure of native starch was destroyed and all RS samples exhibited irregular shaped fragments. Crystal structure of samples changed from A–type to a mixture of B and V–type. The crystallinity of resistant starch also improved as compared with native starch. Moreover, samples with higher resistant starch showed higher relative crystallinity. Differential Scanning Calorimetry (DSC) determination showed that To、Tp、Tc and ΔH all increased which was in agreement with RS content. The resistance of waxy maize starch with Pullulanase treatment to α-amylase digestibility also increased, while the in-vitro digestibility of products decreased.     

玉米淀粉-脂质复合物对曲奇饼干体外消化和血糖生成指数的影响

目的 探究玉米淀粉-脂质复合物的结构和消化特性以及对曲奇饼干的体外消化特性与血糖生成指数的影响。方法 利用水热法制备了制备不同脂质(包括饱和脂肪酸与不饱和脂肪酸)与玉米直链淀粉的复合物, 通过傅里叶红外光谱仪(fourier transform infrared spectroscopy, FT-IR)与X-射线衍射(X-ray diffractometer, XRD)探究了淀粉分子短程和长程有序性。结果 研究表明, 淀粉-脂质复合物的形成使快消化淀粉含量显著降低, 慢消化淀粉和抗性淀粉含量显著增加。水热法制备中通过疏水相互作用得到的淀粉-脂质复合物利用氢键链接使其结构更加稳定, 体外消化速率呈降低趋势。其中玉米淀粉-卵磷脂复合物、玉米淀粉-硬脂酸复合物与玉米淀粉-肉豆蔻酸复合物为 V+B 型晶体结构, 玉米淀粉-大豆油复合物与玉米淀粉-玉米油复合物的晶型结构未发生改变。在五种淀粉-脂质复合物中, 玉米淀粉-卵磷脂复合物的水解率最低, 水解指数预估血糖指数分别为44.65%、64.22%, 所对应的曲奇饼干的水解指数与预估血糖指数也最低, 分别为51.68%、68.08%。结论 表明玉米淀粉-卵磷脂复合物适合作为新型淀粉-脂质复合物用于开发具有低血糖指数的饼干食品。     

Crystallinity and Pasting Properties of Freeze‐Thawed High Amylose Maize Starch

Native and defatted high amylose (about 70%) maize starch gels were freeze‐dried or repeatedly freeze‐thawed, and the effects of the treatments on the crystallinity, pasting viscosity, and resistance to digestive enzymes of the dried starch were examined. Both native and defatted starches showed a B‐type crystal structure in the X‐ray diffractogram, but the crystallinity was decreased by repeating the freeze‐thawing cycle. In the DSC thermogram, the freeze‐thawed starches exhibited two endothermic transitions in the temperature ranges of 90—110 °C and 130—160 °C, representing amyloselipid complexes and amylose‐amylose double helix crystals, respectively. By defatting, the melting enthalpy for the amylose double helices was increased, indicating that the residual lipids inhibited the amylose crystal formation. Ice crystals in the starch gel matrix became smaller and the ice cell membrane became thinner as freeze‐thawing was repeated. The freeze‐dried or freeze‐thawed starch powders swelled to a paste by heating in water as did typical granular starch, but the setback by cooling was significantly high due to the rapid retrogradation of leached amylose. By the treatments, the resistance of the starch to digestive enzymes was also raised. The defatted starches displayed greater paste viscosity and resistance to digestive enzymes than the native starches. But the overall viscosity was decreased as the number of freeze‐thawing cycles increased.     

原花青素抑制玉米淀粉回生作用的研究

目的研究原花青素(OPCs)对高直链玉米淀粉、普通玉米淀粉和高支链玉米淀粉回生的影响。方法采用差示扫描量热仪(DSC)、傅立叶红外光谱仪(FTIR)、核磁共振光谱仪(NMR)测定与分析原花青素与淀粉间的相互作用;同时测定原花青素对淀粉体外消化性的影响。结果结果表明,随着OPCs含量的增加,高直链玉米淀粉回生程度降低;当OPCs添加量为5%时,原花青素对普通玉米淀粉和高支链玉米淀粉回生抑制效果较好。高直链玉米淀粉中慢消化淀粉(SDS)含量随OPCs增加而增加,普通淀粉中SDS含量在添加5%OPCs时较高,而高支链玉米淀粉的快消化淀粉(RDS)含量在5%时较高;NMR结果表明OPCs分子与直链和支链淀粉之间均存在分子间相互作用。结论添加5%原花青素对三种玉米淀粉回生抑制效果较好;原花青素对直链和支链淀粉的结合方式和结合能力不同。     

Effect of hydroxypropyl β-cyclodextrin on physical properties and transition parameters of amylose–lipid complexes of native and acetylated starches

The effect of hydroxpropyl β-cyclodextrin (HPβ-CD) on physical properties and digestibility of wheat, potato, waxy maize and high-amylose maize starches before and after acetylation was studied. Effect of HPβ-CD on amylose–lipid complexes in native and acetylated potato starches synthesized using α-lysophosphatidylcholine was also studied. Acetylation increased swelling factor, amylose leaching, peak viscosity and susceptibility to α-amylase hydrolysis, but decreased gelatinization temperature and enthalpy and gel hardness in all starches. HPβ-CD markedly increased swelling factor and amylose leaching in native and acetylated wheat starches but had little or no impact on other starches. Wheat starch gelatinization enthalpy decreased in the presence of HPβ-CD but gelatinization temperature of all the starches was slightly increased. HPβ-CD had no influence on enzymatic hydrolysis. Melting enthalpy of amylose–lipid complex in both native and acetylated wheat starches was decreased by HPβ-CD. Acetylation also decreased the melting enthalpy of amylose–lipid complex in wheat starch. Similar trend of thermal transitions was observed in the presence of HPβ-CD for the amylose–lipid complexes synthesized in potato starch. Acetylation reduces the complex formation ability of the amylose polymer. Similar to gelatinization, acetylation widened the melting temperature range of amylose–lipid complexes while shifting it to a lower temperature. Higher swelling and amylose leaching, and decreased gelatinization temperature and enthalpy resulting from acetylation of wheat starch is consistent with its influence on starch hydration. Similar effects resulting from the inclusion of HPβ-CD were consistent with the disruption of amylose–lipid complex by HPβ-CD which promotes granular hydration.     

Resistant Starch Content and Structural Changes in Maize (Zea mays) Tortillas During Storage

Storage of maize products such as tortillas may cause starch retrogradation and lead to resistant starch (RS) formation. This study was carried out to determine if storage of maize tortillas under refrigerated conditions enhanced RS content and/or modified RS structure. Improved Costeño variety maize grain was nixtamalized and processed into tortillas which were stored for five and ten days at 5°C. Total resistant starch (TRS) and retrograded resistant starch (RRS or RS3) contents were determined on raw and nixtamalized maize grain and tortillas stored for zero, five and ten days. Differential scanning calorimetry (DSC), X‐ray diffraction (XRD) and near‐infrared (NIR) spectroscopy were use to evaluate structural changes in retrograded resistant starch isolated from each sample type. Total starch content was 67 ± 1.5% for all samples, TRS ranged from 3.3% in the raw grain at 7.2% in tortillas stored for ten days, while RRS starch content ranged from 0% in the raw grain to 3.2% in tortillas stored for ten days. DSC showed endothermic transitions corresponding to amylopectin and amylose retrogradation, at 31.9 and 139.7°C in RRS from tortillas stored for five days, and at 47.9 and 146°C in RRS from tortillas stored for ten days. These values agreed with the higher total RS content recorded after prolonged storage. XRD revealed a starch crystallinity of 13.7% in tortillas stored for five days and 15.3% in those stored for ten days. NIR spectroscopy analysis showed evidence of structural changes in polymeric order that were more pronounced in RRS of tortillas stored for ten days, due to increase in crystalline region.     

High‐Amylose Starches to Bridge the “Fiber Gap”: Development,Structure, and Nutritional Functionality

Although high‐amylose starches are not a recent innovation, their popularity in recent years has been increasing due to their unique functional properties and enhanced nutritional values in food applications. While high‐amylose maize, barley, and potato are commercially available, high‐amylose variants of other main crops such as wheat and rice have once been developed more recently and will be available commercially in the near future. This review summarizes the development, structure, and nutritional functionality of high‐amylose starches developed and reported so far. The range of biotechnological strategies utilized are reviewed, as are the consequent effects on structural properties at different length scales, as well as sensory aspects of foods containing high‐amylose starch (HAS). This review identifies the molecular and microstructural features contributing to digestive enzyme resistance not only in native HAS but also in forms of relevance to food processing. During heat treatment, HAS tends to retain or form dense molecular structures that resist amylase degradation through the retention of the granular structure as well as helices (type‐2 resistant starch [RS]), reassociation of glucan chains (type‐3 RS), and formation of lipid–amylose complexes (type‐5 RS). The review also identifies opportunities for food manufacturers and consumers to incorporate HAS in food products and diets for better nutritional outcomes.     

促进玉米直链淀粉回生的甘薯淀粉晶种的筛选及表征

通过向四次回生的玉米直链淀粉中添加草酸侵蚀的四次回生的甘薯淀粉、甘薯直链和甘薯支链淀粉晶种(质量分数:1%),研究甘薯淀粉晶种对玉米直链淀粉回生的影响。结果表明,甘薯淀粉晶种明显促进了玉米直链淀粉回生长晶,其中甘薯直链淀粉晶种使得玉米直链淀粉回生率达到59.5%,比不添加晶种提高了19.3%。可见吸收光谱研究表明,甘薯淀粉晶种及长晶后的玉米直链淀粉均保持了双螺旋结构。X-射线研究表明草酸侵蚀后甘薯淀粉、甘薯直链淀粉、甘薯支链淀粉均为A+B型。将其分别添加到玉米直链淀粉中并长晶后的样品,结构均为B型。DSC研究表明,甘薯支链淀粉晶种具有最高的吸热焓,说明其晶体含量最高。三种晶种分别促进玉米直链淀粉长晶后的结构较为相似,晶体含量也较相近。该研究为提高淀粉的回生率、研究回生淀粉结晶结构提供良好的技术支持。     

Effects of Fatty Acid Addition on the Physicochemical Properties of Corn Starch

The effect of addition of six fatty acids (stearic, palmitic, myristic, oleic, palmitoleic, and myristoleic acid) on the gelatinization, glass transition, and retrogradation properties of corn starch as well as their complexing abilities with amylose were determined. Differential scanning calorimeter studies reflected that addition of fatty acids caused a 73–89% decrease in the gelatinization enthalpy compared to that of the native starch. Besides amylose-lipid formation, exotherm was determined at the same temperature range with the gelatinization endotherm. As a result, it was suggested that fatty acids complexed with amylose during gelatinization. Fatty acid addition significantly increased the glass transition temperature of starch gel. This was attributed to two reasons: the first is due to the physical cross-linking action of amylose–lipid complexes in starch-water system; the second may be due to the effect of uncomplexed fatty acids on water distribution in the gel structure as a result of their amphiphilic character. Thermal properties of amylose-lipid complexes were compared in order to determine the effect of fatty acid properties. It was found that the shorter chain length and unsaturation favored the complex formation but the complexes formed by longer and saturated fatty acids were more heat stable. Addition of fatty acids resulted in 73–90% and 47–71% reduction in the retrogradation enthalpy compared to native starch gels at 5°C and 21°C, respectively. The reduction in the retrogradation enthalpy was inversely related to the amylose-lipid complexing abilities of the fatty acids and it might be explained by the hindrance effect of uncomplexed fatty acids to the water distribution in the starch gel matrix.     

In vitro availability of starch in heat‐treated potatoes as related to genotype,weight and storage time

The objective of the study was to determine the influence of potato variety, weight and storage time after lifting on the glycaemic index (GI) and resistant starch (RS) content predicted from measurement of the rate and extent of in vitro starch hydrolysis, respectively. The potatoes were either boiled, or boiled and subjected to different heat‐cycling conditions selected to promote retrogradation of amylose or amylopectin, respectively. The hydrolysis indices (HI) and predicted GIs of all 19 potato products were high and fell within narrow ranges of 122–144 and 118–138, respectively. No correlation between average weight of the potato tuber and HI was found. Furthermore, there was no difference in HI between potatoes stored for 1–3 or 8–10 months, nor between varieties of new potato and winter potato. However, the HI was significantly lowered by temperature cycling at conditions known to promote retrogradation of amylopectin (6 °C, 48 h) compared with 6 °C for 24 h followed by 70 °C for 24 h. RS content was already substantial in boiled potatoes, 4.5 g 100 g^?1 (starch basis), and could be increased further by temperature cycling, the highest yield obtained, 9.8 g 100 g^?1 (starch basis), following heat treatment at 6 °C for 24 h followed by 70 °C for 24 h; that is at conditions known to favour amylose retrogradation. Copyright © 2004 Society of Chemical Industry     

Structural,thermal and viscoelastic characteristics of starches separated from normal,sugary and waxy maize

Starches separated from five types of maize (two normal, one sugary and two waxy) were investigated for physicochemical, thermal, amylopectin structure and viscoelastic properties. Kisan and Paras were normal maize while Parbhat and LM-6 were waxy maize type. Apparent amylose content of normal and sugary maize was 29.5–32.6 and 41.0%, respectively. Swelling power of normal, sugary and waxy maize starches was 11.6–15.2, 7.8 and 30.2–39.2 (g/g), respectively. X-ray diffraction of maize starches indicated typical A-pattern. Maize starch showed a single broad peak at 2θ=23.2° and a dual peak 2θ=17°–18.1, respectively. Waxy maize starches showed the presence of greater crystallinity than other starches while sugary maize starch showed the presence of lower crystallinity and a large amount of amylose–lipid complex. Intrinsic viscosity [η] of starches in 90% DMSO at 25 °C was 79.7–119.5 ml g⁻¹ for normal, 70.5 ml g⁻¹ for sugary and 107.2–118.1 ml g⁻¹ for waxy starches. Branch chain–length distribution of amylopectin revealed that the apparent amylose, long side chain- and short side chain-amylopectin proportion ranged between 0.0–41%, 13.4–31.5% and 41.5–66.8%, respectively, among the various maize starches. Maize sugary showed the highest apparent amylose content and the least amount of short- and long-side chains of amylopectin. LM-6 and Parbhat showed higher proportion of both long- and short-chain amylopectin as compared to other starches. Distribution of α-1, 4-chains of amylopectin (short-/long-chain) ranged between 2.1 and 3.4, the least for LM-6 and the highest for Paras starch. The transition temperatures (T_o–T_c) ranged between 60.5 and 76.1 °C for sugary, 63.5–76.3 °C for normal and 64.4–81.3 °C for waxy maize starch. The enthalpy of gelatinization (ΔH_gel) of sugary, normal and waxy maize starches was 2.47, 3.7–4.75 and 4.15–5.4 J/g, respectively. Normal and sugary maize starches showed higher G′ and G″ than waxy type starches. The change in the moduli during cooling and reheating of pastes cooked at different temperatures revealed low disintegration of granular structure in starch with higher amylose and amylose–lipid complex as well as low crystallinity. The changes in moduli during 10 h at 10 °C revealed highest retrogradation in maize sugary followed by Paras and Kisan starch.     

Effect of retrogradation,pancreatin digestion and amylose/amylopectin ratio on the fermentation of starch by Clostridium butyricum (NCIMB 7423)

Using three different maize starches (maize, waxy maize and high amylose maize, containing 25%, 1% and 52% amylose, respectively) the influence of amylose/amylopectin content and of retrogradation on fermentation by the porcine caecal anaerobe Clostridium butyricum was assessed. Small intestine digestion was simulated using pancreatin before the starches were exposed to bacterial fermentation. It was found that retrogradation appeared to alter the extent of the fermentation and hence the amount of short-chain fatty acids produced, while pancreatin digestion appeared to alter the way in which the organism fermented the starch and hence the acetate/butyrate ratio. The amylose/amylopectin ratio seemed to have more influence on the way the starch was fermented by the bacteria after the starch had been subjected to digestion with pancreatic enzymes, but had less influence when the starch had been retrograded. © 1998 SCI.     

直链淀粉晶种对淀粉回生的影响机制

由于淀粉回生影响因素复杂和研究手段局限,基于直链淀粉主导的短期回生阶段和支链淀粉主导的长期回生阶段关联性的回生共性机制未得到系统阐述。基于此,该研究制备短期回生的直链淀粉晶种,采用FTIR、¹³C CP/MAS NMR等手段,研究其诱导大米淀粉的长期回生过程与规律,揭示短期回生与长期回生关联性。结果表明,所制备的直链淀粉晶种粒度分布在200～450 nm,添加晶种导致淀粉短程有序度由0. 670最高提高至0. 887,双螺旋含量由14. 86%最高提高到了22. 80%。回生淀粉的短程有序度、双螺旋含量显著提高,表明所制备直链淀粉晶种显著促进淀粉长期回生过程,这种晶体协同增长效应,丰富了淀粉回生共性机制。     

In vitro starch digestibility,expected glycemic index,and thermal and pasting properties of flours from pea,lentil and chickpea cultivars

In vitro starch digestibility, expected glycemic index (eGI), and thermal and pasting properties of flours from pea, lentil and chickpea grown in Canada under identical environmental conditions were investigated. The protein content and gelatinization transition temperatures of lentil flour were higher than those of pea and chickpea flours. Chickpea flour showed a lower amylose content (10.8–13.5%) but higher free lipid content (6.5–7.1%) and amylose–lipid complex melting enthalpy (0.7–0.8 J/g). Significant differences among cultivars within the same species were observed with respect to swelling power, gelatinization properties, pasting properties and in vitro starch digestibility, especially chickpea flour from desi (Myles) and kabuli type (FLIP 97-101C and 97-Indian2-11). Lentil flour was hydrolyzed more slowly and to a lesser extent than pea and chickpea flours. The amount of slowly digestible starch (SDS) in chickpea flour was the highest among the pulse flours, but the resistant starch (RS) content was the lowest. The eGI of lentil flour was the lowest among the pulse flours.     

Chemical composition and in vitro starch digestibility of corn tortillas with added amaranth flour

Background: Corn tortillas containing 20% (w/w) amaranth flour (AF) were kept in cold storage and analysed after various times for chemical composition and in vitro starch digestibility, including predicted glycemic index. Comparison was made with traditional nixtamalised corn flour (NCF) tortillas. Results: Lipid and protein contents were higher in mixed NCF/AF tortilla than in NCF tortilla. Available starch (AS) content was lower in NCF/AF tortilla and decreased during cold storage. However, this decrease was greater in NCF tortilla, suggesting slower starch retrogradation in NCF/AF tortilla. After 96 h of storage, total resistant starch (RS) content was higher in NCF tortilla than in NCF/AF tortilla. However, no differences were detected thereafter, indicating similar retrogradation after long storage times. Retrograded resistant starch contents indicated that only part of the total RS in tortilla is due to retrogradation, which agrees with the tendency recorded for AS and RS in both types of tortilla. α‐Amylolysis rates were similar in NCF/AF and NCF tortillas, decreasing with storage. The predicted glycemic index was always higher in NCF/AF tortilla, a pattern that might be due to the waxy‐type starch present in AF. Conclusion: NCF/AF tortilla might be suitable as a product with higher protein content and higher glycemic index than conventional NCF tortilla. Copyright © 2007 Society of Chemical Industry     

低温挤压法制备玉米淀粉-GMS复合物及其回生性质研究

为解决玉米淀粉易于回生的难题,试验探讨了挤压蒸煮制备玉米淀粉酯复合物的结构和回生机理。试验结果表明:玉米淀粉-GMS复合物的回生凝胶焓值和回生凝胶温度低于原玉米淀粉的回生凝胶焓值和回生凝胶温度。X射线衍射分析原玉米淀粉属于A型衍射图,经挤压蒸煮处理制备的玉米淀粉-GMS复合物属弱V型结晶结构。FT-IR光谱的分析可知,玉米淀粉-GMS复合物的进程结晶度降低,在1735 cm~(-1)处有吸收峰,玉米淀粉与分子蒸馏单甘酯(GMS)发生酯交换反应生成了玉米淀粉-GMS复合物,分子蒸馏单甘酯能有效抑制玉米淀粉回生。随分子蒸馏单甘酯添加量的增加,分子蒸馏单甘酯对玉米淀粉回生的抑制作用增加显著。在食品工业生产中,玉米淀粉-GMS复合物是非常有应用价值抗回生的高质量淀粉基产品。     

In vitro starch digestibility changes during storage of maize flour tortillas

Nixtamalized maize flours elaborated by four factories in Mexico were used for tortilla preparation. Samples were stored at 4 degrees C for up to 72 h and their in vitro starch digestibility features were evaluated. Moisture content was different between flour and tortilla but no evident relation could be established. Protein and lipid levels were lower in tortillas than in flour but ash content was not different in both samples. A decrease in available starch content was observed upon 48 h cold storage (4 degrees C), changes that were concomitant with increased total resistant starch (RS) levels. These changes were due mainly to retrogradation, as suggested by the increased retrograded resistant starch (RRS) levels recorded in stored tortillas; in some samples, RRS represented up to 100% of total RS. The digestion (alpha-amylolysis) rate (DR) of freshly prepared tortillas differed for the various samples. Although the amylolysis patterns for fresh and 72 h-stored tortillas were similar, lower DR values were shown for the stored materials. The differences found among the various tortilla samples may be due to variations in processing conditions during commercial maize flour preparation, and to the use of different maize varieties.     

Retrogradation of Potato Starch as Studied by Fourier Transform Infrared Spectroscopy

Retrogradation kinetics for a potato starch-water system (10% w/w gel) was monitored by Fourier Transform Infrared spectroscopy and compared with waxy maize starch. The spectra showed the C-C and C-O stretching region (1300-800 cm⁻¹) to be sensitive to the retrogradation process. A multi-stage process was observed during the retrogradation of potato starch and characterized as the formation of short- and long-range order. The first stage was characterized as the formation of helices and the fast formation of crystalline amylose regions. The second stage was described as the induction time for amylopectin helix aggregation. Stage three was described as the helix-helix aggregation and the crystallization of amylopectin. The overall-first order calculated rate constant of potato starch was (9.6±1.4) 10⁻ 3h⁻¹. The calculated rate constant were in agreement with the known difference in retrogradation kinetics of waxy maize and potato starch. The effects were explained by the differences in retrogradation rate of amylopectin and amylose. Potato starch consists of amylose as well as amylopectin. Whereas amylose crystallization occurs within a few hours, amylopectin crystallization is slow and takes a few weeks.     

4种杂豆淀粉结构特征和理化特性比较

以4种我国广泛种植的杂豆为原料，采用湿磨法提取豇豆淀粉、扁豆淀粉、豌豆淀粉、红芸豆淀粉，并对4种杂豆淀粉的结构特征和理化特性进行比较。结果表明：杂豆淀粉的红外光谱均呈现典型的淀粉类多糖结构特征，颗粒完整光滑，主要呈现肾型和椭圆形。样品的平均流体力学半径大小顺序为豇豆淀粉>豌豆淀粉>扁豆淀粉>红芸豆淀粉，扁豆淀粉为CC-型晶体，其余为C_A-型晶体，样品间的相对结晶度差异较大(27.6%～38.5%)。4种杂豆淀粉的糊化特性差异显著，糊化温度均较高(75.3～82.8℃)，不易糊化。豇豆淀粉直链淀粉含量最低(26.3%)，其热糊稳定性优于其他杂豆淀粉，具有不易老化的特性。红芸豆淀粉的直链淀粉含量最高(31.5%)，回生值最高(3 182.3 mPa·s)，最易发生老化行为。综上，4种杂豆淀粉的颗粒形貌相似，均为C-型晶体，分子结构和糊化特性差异较大，凝沉特性相近。