Starch Crystals Research Articles

Structural and physicochemical properties of rice starch from a variety with high resistant starch and low amylose content.

Research on the physicochemical properties of rice-derived endo-sperm high resistant starch (RS) with low amylose content (AC) is limited. In this study, we evaluated the physicochemical characteristics of such a starch variety and revealed that the starch granules exhibit a smoother, more refined surface with distinct edges, increased compactness, higher order of surface, and fewer cavities compared to those of a low RS rice variety. The starch crystal was classified as an A-type, which may be connected to the high amylose-lipid complex content. The branched internal long chains (B2 + B3) were abundant, allowing for easy entanglement with other molecular chains and a compact structure. Differential scanning calorimetry revealed the need for high temperature and energy to disrupt the double helix structure within the crystallization region of starch. Furthermore, starch viscosity analysis revealed a high cold paste viscosity, consistency, and setback value, with recrystallization yielding a stable structure, increased viscosity, and enhanced hydrolysis resistance to enzymes.

Effect of atmospheric pressure plasma jet on the structure and physicochemical properties of wheat starch.

The effect of atmospheric pressure plasma jet (APPJ) with different discharge power (0, 400, 600, and 800 W) on the structure and physicochemical properties of wheat starch were evaluated in this study. After APPJ treatments, significant declines in peak viscosity, breakdown viscosity, and final viscosity of wheat starch pasting parameters were observed with increase of plasma treatment power. Being treated with discharge power of 800 W, the PV and BD value of wheat starch paste significantly dropped to 2,578 and 331 cP, respectively. Apparently, APPJ could raise the solubility of wheat starch, while reduce the swelling capacity, and also lower the G' and G″ value of wheat starch gel. Roughness and apparent scratch was observed on the surface of the treated wheat starch granules. Although APPJ treatment did not alter wheat starch's crystallization type, it abated the relative crystallinity. APPJ treatment might be useful in producing modified wheat starch with lower viscosity and higher solubility.

Preparation of gelatin-starch shell-yolk microspheres by water-in-water emulsion method: Effects of starch crystal type and cross-linking

In this study, gelatin-starch shell-yolk microspheres were prepared by water-in-water emulsion method using three different crystal types of plant rhizome starches. The microspheres were then cross-linked using chemical and natural cross-linking agents. The effects of starch crystal type and cross-linking on microsphere quality were investigated. The morphology of microspheres was spherical or nearly spherical and possessed a smooth surface. Uncross-linked microspheres had a high swelling capacity of up to about 750%. After cross-linking, the swelling of the microspheres was inhibited, and a denser structure was formed. The loading capacity of microspheres was related to their swelling capacity. The results of DSC showed that the gelatin shell of the microspheres retarded the internal starch pasting, and the thermal stability of the microspheres could be enhanced by cross-linking. Cross-linking similarly increased the resistance of the microspheres to amylase hydrolysis by about 10%. Therefore, microspheres should be cross-linked after adequate encapsulation of the cargo to obtain both high encapsulation efficiency and high stability. In addition, the microspheres prepared from three different crystal types of starch were coincidentally B + V mixed type. These results are instructive for the future utilization of such microspheres for encapsulating bioactive.

Preparation of Multi‐Grain Flour with High Content of Resistant Starch and the Mechanism Underlying the Improved Digestion Resistance

AbstractTo acquire the optimum treatment strategy that leads to the highest yield of resistant starch (RS) in multigrain flour (MF), wheat flour, whole oat flour, and whole buckwheat flour are used to prepare antidigestive MF by using pullulanase debranching combining heat–moisture treatment (P‐HMT). Based on the single factor tests and response surface analysis, the optimum conditions for the treatment of MF are determined as follows: pullulanase 62.6 U g−1, autoclaving 21.3 min, HMT at 100 °C, and 30.4% water content for 6.0 h. Under these conditions, the yield of RS in the flour reaches 77.42%. P‐HMT causes protein denaturation, starch gelatinization, and flour clumps in MF, facilitating starch recrystallization and interactions among short‐chain starch, monomeric proteins, and lipids. All these findings are further confirmed by the conversion of starch crystal from A‐type to B+V‐type, the improvement of starch short‐range molecular order, and the presence of more binary/ternary complexes in treated flour. In brief, the starch digestion resistance improvement in the treated flour is attributed to the recrystallization of short‐chain starch and interactions between starch and protein/lipid.

A multihole nozzle controls recrystallization of high-moisture extruded maize starches: Effect of cooling die temperature

Hot extrusion is utilized for starch modification due to its high mechanical input and product output. Amylose recrystallization commences and primarily depends on intermolecular interactions after conventional extrusion. Hence, the design of a new component based on the existed extrusion system was aimed at facilitating molecular aggregation, potentially accelerating starch recrystallization. In this study, a nozzle sheet comprising 89 holes was integrated into the cooling die. The impact of the multihole nozzle on the structure and in vitro digestibility of extruded maize starches after retrogradation was examined at varying cooling die temperatures. The results showed that the nozzle-assembled extrusion system operated effectively without additional mechanical or yield losses. At 50 °C, the crystallinity of nozzle-produced starch was approximately 70 % higher than that of conventionally extruded starch, predominantly owing to the B-type allomorph of the amylose double helix. Recrystallized amylopectin was also found in these nozzle-produced starches, indicating that multihole nozzle-induced uniaxial elongational flow resulted in the rapid starch crystallization. The increased formation of recrystallized amylose led to improved molecular order in starch structures while reducing their digestibility. These findings revealed a new approach to improve starch crystallinity by incorporating a nozzle sheet in the extrusion process.

Large flour aggregates containing ordered B + V starch crystals significantly improved the digestion resistance of starch in pretreated multigrain flour

The starch digestibility of flour is influenced by both physicochemical treatment and flour particle size, but the interactive effect of these two factors is still unclear. In this study, the effect of pullulanase debranching, combined with heat-moisture treatment (P-HMT), on starch digestibility of multi-grain flours (including oat, buckwheat and wheat) differing in particle size was investigated. The results showed that the larger-size flour always resulted in a higher resistant starch (RS) content either in natural or treated multi-grain flour (NMF or PHF). P-HMT doubled the RS content in NMFs and the large-size PHF yielded the highest RS content (78.43 %). In NMFs, the cell wall integrity and flour particle size were positively related to starch anti-digestibility. P-HMT caused the destruction of cell walls and starch granules, as well as the formation of rigid flour aggregates with B + V starch crystallite. The largest flour aggregates with the most ordered B + V starch were found in large-size PHF, which contributed to its highest RS yield, while the medium- and small-size PHFs with smaller aggregates were sensitive to P-HMT, resulting in the lower ordered starch but stronger interactions between starch and free lipid or monomeric proteins, eventually leading to their lower RS but higher SDS yield.

Use of flours from traditional pan and salt‐bed‐roasted Kodo grains in the production of breakfast cereal: Spatial, morphological, techno‐functional, structural, and rheological analyses

AbstractKodo millet, possesses the goodness of iron and low glycemic index, notably, its starch has inadequate application owing to retrogradation and low amylose content. Dry‐roasting seems worthy as an inexpensive pretreatment process to preserve desirable textural characteristics of whole cereal grains with peculiarity of moisture levels below 20% for a very short time. The aim of this work was to analyze indepth studies to explain morphological, techno‐functional, structural, and rheological transformation of Kodo starch components generated during roasting of conditioned whole kernels at 15% and 20% initial moisture content (IM). The micrographs displayed a honeycomb‐like structure in all roasted flours. The X‐ray diffraction intensity decreased and showed partial rupture to A‐type orthorhombic crystals of Kodo starch after roasting, while lamellar growth across the multilayer matrix was also generated (23° and 37.35°). The fusion of the starch granules with endosperm's macromolecules observed plausible techno‐functional, and rheological properties, emphasized as non‐nutritional properties substantially improved sensory attributes of food as an additive. Roasted flour at higher IM thus made it easier to integrate into instant ready‐to‐eat breakfast cereals of improved amylose content (23.69%–29.31%) with lowered water activity (.4671–.5170) of varied skin strength (196.17–1894.41 g), elasticity (4.03–10.21 mm), and cell size (164.03–1059.10 μm) detected from puncture‐test force measurement. The infrared absorbance band illustrated loss of peak at 1047 cm−1 and endosperm's expansion (195.34%–309.30%) lowered kernel hardness (42.3–17.78 N) indicated structural loss upon roasting, may significantly reduce milling cost, and provide a commercially pretreated readied kernel or flour for industrial applications.Practical applicationsKodo millet, of the Poaceae family thrives well in abiotic stress and scanty rainfall exhibit meager application owing to low amylose content. Applying preprocessing traditional roasting techniques upon moistened kernel, get popped cereal. Milling of such cereal retards subcellular loss, indicating increased amylose, water, and oil absorption with avid aroma. This is critical in the preparation of cost‐effective dietary formulations for children and geriatrics, thus making it easier for integration into ready‐to‐eat wholesome breakfast cereals.

Effects of Wheat Oligopeptide on the Baking and Retrogradation Properties of Bread Rolls: Evaluation of Crumb Hardness, Moisture Content, and Starch Crystallization

Delaying the deterioration of bakery goods is necessary in the food industry. The objective of this study was to determine the effects of wheat oligopeptide (WOP) on the qualities of bread rolls. The effects of WOP on the baking properties, moisture content, and starch crystallization of rolls during the storage process were investigated in this study. The results showed that WOP effectively improved the degree of gluten cross-linking, thereby improving the specific volume and the internal structure of rolls. The FTIR and XRD results showed that the addition of WOP hindered the formation of the starch double helix structure and decreased its relative crystallinity. The DSC results revealed a decrease in the enthalpy change (ΔH) from 0.812 to 0.608 J/g after 7 days of storage with 1.0% WOP addition, further indicating that WOP reduced the availability of water for crystal lattice formation and hindered the rearrangement of starch molecules. The addition of WOP also improved the microstructure of the rolls that were observed using SEM analysis. In summary, WOP is expected to be an effective natural additive to inhibit starch staling and provide new insights into starchy food products.

Characterization of the starch molecular structure of wheat varying in the content of resistant starch

Resistant starch (RS) is the total amount of starch that is incompletely or not digested and absorbed in the small intestine. It plays a role similar to dietary fibre with beneficial effects for human health. In this study, the RS content of 129 wheat accessions was determined, and the relationship between the several starch physical properties and resistant starch content were analyzed. By comparing the total starch content, amylose starch content, starch chain length distribution, starch crystallization type, starch branching degree, and starch granule morphology between the high RS and low RS content wheat accessions, it was found that the amylose content and RS content were significantly positively correlated. However, in the range of chain length fb 3 (DP ≥ 37), there was a significant negative correlation between amylopectin content and RS content. The surface of starch granules became increasingly smooth as the content of RS increased.

Optimizing techno-functionality of germinated whole wheat flour steamed bread via glucose oxidase (Gox) and pentosanase (Pn) enzyme innovation

Germination, a powerful biofortification technique, holds immense potential in bolstering the micronutrient profile of essential staple grains, thereby paving the way for optimal nutritional enhancement. The primary goal of this study was to improve the technological functionality of germinated wheat flour by incorporating pentosanase (Pn) and glucose oxidase (Gox) enzymes, with particular emphasis on the evolutionary changes in its components. The inclusion of Gox did not produce any substantial impact on the volumetric characteristics of the steamed bread. The incorporation of Pn and Gox has been seen to enhance the overall excellence of steamed bread by optimizing loaf volume and textural characteristics while also improving the thermal stability of the dough. The existence of two endothermic peaks could be attributed to bound water or alterations in the granules within the starch crystallization region. Adding Pn and Gox reduced and increased the formation and stability time of the dough, respectively. A certain ratio was employed to assess alternations in the crystallinity of starch granules over a limited range. After steaming, a significant decrease in IR1047/1022 was observed, indicating that the elevated temperature partially disrupted the internal starch crystal structure, leading to a gelatinization reaction with water. The ratio of tensile resistance (R) and elongation (E) of dough increased significantly compared to the control. The results obtained from this study indicate that the simultaneous inclusion of enzymes (Pn + Gox) holds significant promise for expanding the technological functionality of germinated wheat flour dough and improving the quality attributes of steamed bread.

Effect of Lignin Concentration on Crystallinity of TPS/Lignin Biocomposite

Several alternatives have been considered to minimize the environmental impact caused by conventional polymers. The integration of lignin into the starch matrix is one extensively used substitute. The purpose of this study is to ascertain how much lignin influences how crystallin the palm starch biocomposite is. In a twin-screw extruder, palm starch, glycerol, stearic acid, and lignin are extruded. The properties of the palm starch crystals were examined using XRD. According to the results of X-ray diffraction (XRD), palm starch has a type C crystal structure. Palm starch, TPS, and TPSL have percentages of crystallinity of 57.6%, 51.9%, 55.7%, 56.3%, 60.1%, 63.4%, and 66.4%, respectively. The addition of lignin to the starch matrix can increase along with the increase in lignin content.

Structure changes of ethanol–water modified oat flour and the influence on the processing qualities of oat noodles

The oat dough lacks viscoelasticity and hinders its utilization in noodles. In this study, oat flour was modified by ethanol–water treatment, the changes in starch structure and properties during modification, and the influence of modified oat flour on the processing qualities of noodles containing 50% oat flour was investigated. The granular cold–water swelling starch (GCWS) was prepared during the modification, and the A–type starch crystal transformed to the V–type. No endothermic peaks were observed in the DSC thermograms. Modified oat flour has an advantage over oat flour in that it has higher cold water viscosity. As the modified oat flour content rose from 0% to 10%, the tensile strength of dough sheet increased from 345.57 g to 367.19 g, the transverse relaxation time (T2) of water molecules increased. Water absorption of cooked oat noodles rose from 125.18% to 129.32%, with a reduction in cooking loss from 10.12% to 8.97%. The shear force, which indicates the hardness of cooked oat noodles, showed a decline of from 210.83 g to 190.02 g. The mentioned results indicated the ethanol–water treatment prepared GCWS, and that improves the processing quality of dough sheets via the increase of its tensile strength.

Effects of postponing nitrogen topdressing on starch structural properties of superior and inferior grains in hybrid indica rice cultivars with different taste values.

Nitrogen (N) fertilizer management, especially postponing N topdressing can affect rice eating quality by regulating starch quality of superior and inferior grains, but the details are unclear. This study aimed to evaluate the effects of N topdressing on starch structure and properties of superior and inferior grains in hybrid indica rice with different tastes and to clarify the relationship between starch structure, properties, and taste quality. Two hybrid indica rice varieties, namely the low-taste Fyou 498 and high-taste Shuangyou 573, were used as experimental materials. Based on 150 kg·N hm-2, three N fertilizer treatments were established: zero N (N0), local farmer practice (basal fertilizer: tillering fertilizer: panicle fertilizer=7:3:0) (N1), postponing N topdressing (basal fertilizer: tillering fertilizer: panicle fertilizer=3:1:6) (N2). The starch granules of superior grains were more complete, and the decrease in small granules content and the stability of starch crystals were a certain extent less than those of inferior grains. Compared with N1, under N2, low-taste and high-taste varieties large starch granules content were significantly reduced by 6.89%, 0.74% in superior grains and 4.26%, 2.71% in inferior grains, the (B2 + B3) chains was significantly reduced by 1.61%, 0.98% in superior grains, and 1.18%, 0.97% in inferior grains, both reduced the relative crystallinity and 1045/1022 cm-1, thereby decreasing the stability of the starch crystalline region and the orderliness of starch granules. N2 treatment reduced the ΔHgel of two varieties. These changes ultimately contributed to the enhancement of the taste values in superior and inferior grains in both varieties, especially the inferior grains. Correlation analysis showed that the average starch volume diameter (D[4,3]) and relative crystallinity were significantly positively correlated with the taste value of superior and inferior sgrains, suggesting their potential use as an evaluation index for the simultaneous enhancement of the taste value of rice with superior and inferior grains. Based on 150 kg·N hm-2, postponing N topdressing (basal fertilizer: tillering fertilizer: panicle fertilizer=3:1:6) promotes the enhancement of the overall taste value and provides theoretical information for the production of rice with high quality.

Effect of fish skin gelatin on characteristics and staling properties of bread made from pre-baked frozen dough

Using hydrocolloids as an additive in different foods is becoming increasingly common, especially in wheat-based products, to improve their quality. This paper investigated the effect of fish skin gelatin on the quality of the bread made from pre-baked frozen dough and its staling properties during storage. The results showed that the addition of fish skin gelatin (0.0%, 0.5%, 1.0% and 1.5% on flour) significantly reduced the hardness and the baking loss of bread and increased the specific volume of bread (P < 0.05). When 0.5% fish skin gelatin was added, the hardness of bread was reduced by 28.07%, and the specific volume increased from 2.99 cm3/g to 3.44 cm3/g. During the 7 days of storage, compared to the control group, bread and starch samples containing 0.5% gelatin had the lowest enthalpy of retrogradation at 1.90 J/g and 1.74 J/g, followed by 1.0% and 1.5% gelatin samples, indicating that gelatin can restrain the diffusion of water, and further limit water migration and vaporization. The relative crystallinity of bread and starch decreased by 17.50% and 38.45%, respectively, which demonstrated the mitigating effect of starch crystallization. The decline in absorbance ratio of FT-IR at R1047/1022 and R1022/995 also confirmed that the addition of gelatin could delay starch retrogradation. These results indicated that fish skin gelatins have potential applications in delaying starch retrogradation and extending the bread shelf-life.

Starch ordered structures control starch reassembly behaviors during heat–moisture treatment for modulating its digestibility

This study investigated the effect of starch crystallinity on starch reassembly behaviors during the heat–moisture treatment (HMT) using starches with A-type crystal content of 0.00%–19.03%. The results showed that HMT reduced the native starch crystal content from 19.03% to 15.02% and increased starch thermostability, leading to a decrease in rapidly digestible starch (RDS) content from 86.91% to 76.71%. Moreover, starches containing a crystal content of 2.51%–8.11% exhibited significant reassembly during the HMT, and the resulting modified starches had more crystals and less RDS of 63.43%–69.31%. Interestingly, starches lacked A-type crystals but had some helical structures exhibiting A-type crystalline structures and lower digestibility after HMT. These findings verified that starch could significantly reassemble to form crystalline structures during the HMT. Controlling the crystal content of starch granules, particularly between 2.51% and 8.11%, was a promising approach for promoting starch reassembly during HMT and reducing starch digestibility.

Технологические свойства теста из смеси ржаной и пшеничной муки с продуктами переработки облепихи

Processed fruit and berry raw materials often become part of bakery formulations. They increase the nutritional value of the finished product and change the rheological properties of the dough. Processed sea buckthorn (Hippophaё rhamnoides L.) maintains natural biochemical properties, which makes it a valuable food ingredient. The research objective was to conduct a comprehensive study of the technological properties of dough made of rye and wheat flour with sea buckthorn meal and dry sea buckthorn extract.&#x0D; The research involved sea buckthorn extract and meal mixed with wheat and rye flour, as well as dough and bread from the experimental flour mixes. The experimental part included standard methods used in the bakery industry.&#x0D; The sea buckthorn meal and extract contained protein (10.3 and 4.3%), crude fiber (8.7 and 0.3%), pectin (5.27 and 0.11%), and ascorbic acid (21.63 and 53.68 mg/100 g). They were highly acidic: 4.9 and 3.0%, respectively. As a result, protein substances and dietary fibers took a longer time to swell. The high acidity also inhibited α-amylase, which improved the rheological properties but increased the dough development time and stability. The sea buckthorn products had a positive effect on the starch crystallization processes and reduced the storage-related starch degradation. The sensory evaluation of the bread described its shape as regular, with fluffy crumb and pleasant sea buckthorn flavor. &#x0D; Thus, sea buckthorn meal and extract proved excellent technological acidifiers and regulators of amylolytic activity. The additives made it possible to reduce the amount of liquid rye sourdough from 30 to 15% and the fermentation time because the dough acidity reached 7.5–8.0 degrees.

Debranching facilitates malate esterification of waxy maize starch and decreases the digestibility

In this study, the debranching followed by malate esterification was employed to prepare malate debranched waxy maize starch (MA-DBS) with a high degree of substitution (DS) and low digestibility using malate waxy maize starch (MA-WMS) as the control. The optimal esterification conditions were obtained using an orthogonal experiment. Under this condition, the DS of MA-DBS (0.866) was much higher than that of MA-WMS (0.523). A new absorption peak was generated at 1757 cm−1 in the infrared spectra, indicating the occurrence of malate esterification. Compared with MA-WMS, MA-DBS had more particle aggregation, resulting in an increase in the average particle size from scanning electron microscopy and particle size analysis. The X-ray diffraction results showed that the relative crystallinity decreased after malate esterification, in which the crystalline structure of MA-DBS almost disappeared, which was consistent with the decrease of decomposition temperature by thermogravimetric analysis and the disappearance of the endothermic peak by differential scanning calorimeter. In vitro digestibility tests showed an order: WMS > DBS > MA-WMS > MA-DBS. The MA-DBS showed the highest content of resistant starch (RS) of 95.77 % and the lowest estimated glycemic index of 42.27. In a word, pullulanase debranching could produce more short amylose, promoting malate esterification and improving the DS. The presence of more malate groups inhibited the formation of starch crystals, increased particle aggregation, and enhanced resistance to enzymolysis. The present study provides a novel protocol for producing modified starch with higher RS content, which has potential application in functional foods with a low glycemic index.

Microstructural, physicochemical properties and starch digestibility of brown rice flour treated with extrusion and heat moisture

Effects of heat moisture treatment (HMT), extrusion treatment (ET), and the combination treatment (HMT-ET) on microstructural, physicochemical properties, and starch digestibility of brown rice flour (BRF) were investigated. With a rise in resistant starch (RS), melting temperature, and a decrease in swelling capacity (SC), peak viscosity, and apparent amylose content (AAC), the HMT-ET BRF showed a significant lower expected glycemic index (eGI) than HMT and ET. XRD and FTIR results showed ET, HMT-ET caused the transition of starch crystals from amorphous to crystalline region, suggesting the formation of the starch-lipid complex. The analysis of DSC and RVA proved HMT-ET flours induced starch gelatinization and inhibited the starch retrogradation of BRF compared with the other three flours. Correlation analysis suggested that the combined effect of HMT and ET was response for the changes in physicochemical properties and reduction of in vitro starch digestibility. Overall, the BRF after HMT-ET with improved physicochemical properties and starch digestibility could be better utilized as a good substitute for carbohydrate sources.

Acylated pectin/gelatin-based films incorporated with alkylated starch crystals: Characterization, antioxidant and antibacterial activities, and coating preservation effects on golden pomfret

Pectin and starch crystals were modified by ethyl gallate and octadecyl-trimethoxysilane, respectively, followed by using acylated pectin (AP) and alkylated starch crystals (ASCs) as bioactive reagents and hydrophobic enhancers to improve the physiochemical properties of gelatin-based films and evaluate their coating preservation effects on golden pomfret. The properties of AP and ASC were investigated by Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), proton-nuclear magnetic resonance (1H NMR) and X-ray diffraction (XRD). The ethyl-gallate-modified pectin/gelatin (AP/G) containing 3 % ASC (AP/G/ASC-3 %) was shown to have the maximum tensile strength and Young's modulus of all the tested composite films. The AP/G containing 10 % ASC exhibited a water contact angle higher than 94°, coupled with a significant improvement in UV-shielding efficiency. FTIR and SEM analysis of the AP/G/ASC-3 % film indicated that the molecular interactions in the composite film components were noncovalent linkages, including hydrogen bonds, hydrophobic interactions, and electrostatic interactions, contributing to homogeneous and smooth microstructures. Additionally, the solutions of AP/G and AP/G/ASC composite films presented obvious antioxidant and antibacterial activities against Escherichia coli and Staphylococcus aureus. Furthermore, the AP/G and AP/G/ASC active coatings could effectively inhibit lipid oxidation and improve the textural acceptability of golden pomfret (Trachinotus blochii) fillets during 4 °C storage.

The relationship between the fine structure of amylopectin and the type of crystalline allomorph of starch granules in rice endosperm

AbstractBackground and ObjectivesIt is known that any wild‐type varieties of cereals so far examined have A‐type starch crystals in their endosperm whereas their starch branching enzyme 2b (be2b) mutants that are usually referred to as amylose‐extender (ae) mutants produce B‐type starch crystals. The present study aimed to examine the structural features of amylopectin which are responsible for the A‐type or B‐type crystalline allomorphs of starch granules by using starches in wild‐type japonica and indica rice varieties and their be2b (ae) mutants.FindingsThe average length of chains of A‐type amylopectin was markedly shorter than that of B‐type amylopectin. It was also thought that A‐type amylopectin had two types of branches, namely the first branches were formed mainly by BEI in the basal region of the cluster and the second branches were synthesized specifically by BEIIb inside the cluster. These differences caused the average length of double helices formed by cluster constituent chains to be shorter in wild‐types than that in their be2b mutants, and these differences changed the crystalline allomorph of starch granules to B‐type in the mutants from A‐type in their wild‐types, as examined by wide angle X‐ray diffraction and sum frequency generation spectroscopy.ConclusionsCombined with these observations and calculations of chain‐length of hypothetical A chains in four types of amylopectin molecules, it was concluded that both the average length of external segments of cluster chains and the formation of the second branches inside the cluster greatly affect the crystal types of starch granules.Significance and NoveltyThe novel findings in the present study can provide new insights into the structural features of amylopectin which determine the A‐type or B‐type crystalline allomorph of starch granules of cereals.