Amylopectin Branch Research Articles

Amorphous packing of amylose and elongated branches linked to the enzymatic resistance of high-amylose wheat starch granules

To elucidate starch structural features underlying resistant starch formation, wheat starch granules with three (A-, B- and C- type) crystalline polymorphisms and a range of amylose contents were digested in vitro. The changes in multi-level structure of digestion residues were compared. In the residues of A- and C-type starches, the molecular fine structure (distributions of chain length and whole molecular size), as analyzed by size exclusion chromatography (SEC), remained similar during digestion. In contrast, B-type high amylose wheat starch (HAWS) showed distinct changes in multi-level structures of digestion-resistant fractions: (1) the peak of longer amylopectin branches shifted to a lower degree of polymerization (40 DP); (2) production of α-limit dextrin (~2 nm hydrodynamic radius) in the residues; (3) a small increase of double helix content during digestion, in contrast to 6 % reduction for the A-type starch; (4) a decrease (6 °C lower) in the melting temperature of amylose-lipid complexes. The comparison suggests that elongated branches in B-type starch contribute to the formation of resistant fraction (including α-limit dextrin) against α-amylase. The amorphous packing of starch polymers with elongated branches together with the absence of surface pores and channels is proposed to be the basis for the enzymatic resistance of granular HAWS.

Improving Agricultural Traits While Maintaining High Resistant Starch Content in Rice

BackgroundResistant starch (RS) is beneficial for human health. Loss of starch branching enzyme IIb (BEIIb) increases the proportion of amylopectin long chains, which greatly elevates the RS content. Although high RS content cereals are desired, an increase in RS content is often accompanied by a decrease in seed weight. To further increase the RS content, genes encoding active-type starch synthase (SS) IIa, which elongates amylopectin branches, and high expression-type granule-bound SSI (GBSSI), which synthesizes amylose, were introduced into the be2b mutant rice. This attempt increased the RS content, but further improvement of agricultural traits was required because of a mixture of indica and japonica rice phonotype, such as different grain sizes, flowering times, and seed shattering traits. In the present study, the high RS lines were backcrossed with an elite rice cultivar, and the starch properties of the resultant high-yielding RS lines were analyzed.ResultsThe seed weight of high RS lines was greatly improved after backcrossing, increasing up to 190% compared with the seed weight before backcrossing. Amylopectin structure, gelatinization temperature, and RS content of high RS lines showed almost no change after backcrossing. High RS lines contained longer amylopectin branch chains than the wild type, and lines with active-type SSIIa contained a higher proportion of long amylopectin chains compared with the lines with less active-SSIIa, and thus showed higher gelatinization temperature. Although the RS content of rice varied with the cooking method, those of high RS lines remained high after backcrossing. The RS contents of cooked rice of high RS lines were high (27–35%), whereas that of the elite parental rice was considerably low (< 0.7%). The RS contents of lines with active-type SSIIa and high-level GBSSI expression in be2b or be2b ss3a background were higher than those of lines with less-active SSIIa.ConclusionsThe present study revealed that backcrossing high RS rice lines with elite rice cultivars could increase the seed weight, without compromising the RS content. It is likely that backcrossing introduced loci enhancing seed length and width as well as loci promoting early flowering for ensuring an optimum temperature during RS biosynthesis.

Modification of granular waxy, normal and high-amylose maize starches by maltogenic α-amylase to improve functionality

Maltogenic α-amylase (MGA) was used to modify granular waxy (WMS), normal (NMS), and high-amylose maize (HAMS) starches for improved functional attributes. MGA treatment for 24 h shortened the amylopectin branch chains of WMS and NMS, which considerably retarded their retrogradation during cold storage. Due to the effective degradation at both granular and molecular levels, MGA modification markedly diminished the pasting viscosities of WMS and NMS. The MGA treatment increased the resistant starch (RS) content of cooked NMS from 2.6% to 7.3%, resulting from the formation of retrograded amylose in MGA-modified NMS during incubation at 37 °C in the Englyst Assay. Different from the effective hydrolysis on WMS and NMS using an “inside-out” pattern, MGA hydrolyzed HAMS to a very low degree through “surface pitting”, thus showing limited influence on its functionality. The reported novel findings will be meaningful for utilizing MGA to develop “clean-label” starch ingredients with enhanced functional properties.

Differences in the functional properties and starch structures of early/late season rice between the early and late seasons

In the double rice cropping system, early/late season rice cultivars can be grown in both early and late seasons. However, the functional properties and starch structures of early/late-season rice between the early and late seasons are still unclear. Here, we conducted a field experiment with two typical early/late season rice cultivars. Compared to early rice, late rice had higher hardness and stickiness and lower peak viscosity, breakdown, and pasting temperature. The higher hardness, lower peak viscosity and breakdown of late rice were dominated by its higher amylose content (i.e., the proportion of amylose chains, DP 100–10000). The lower crystallinity and ratio of 1045/1022 cm−1 of late rice was due to its long and very long amylopectin branch chains (DP 25–70), resulting in a lower pasting temperature. We considered that the higher stickiness of late rice was due to a higher proportion of short and medium amylopectin branch chains (DP 6–24). Furthermore, the setback (short-term retrogradation) showed a significant difference between cultivars, which might be related to the difference in long amylopectin branch chains (DP 37–70) and their intermolecular interactions with amylose molecules. These findings are expected to provide important information for improving rice palatability and developing the rice industry of early/late season rice in the double rice cropping system.

Application of Exogenous 6‐benzyladenine at the Silking‐Stage Improves the Starch Quality of Waxy Maize Suffering from Post‐Silking Drought Stress

AbstractThe application of exogenous 6‐benzyladenine (6‐BA) can mitigate plant responses to drought stress. The effects of spraying exogenous 6‐BA at the silking‐stage on the waxy maize starch physicochemical properties under post‐silking well‐watered and drought conditions are studied using Jingkenuo2000 (JKN2000) and Yunuo7 (YN7) as materials. The starch granule size in response to drought is enlarged in JKN2000 but reduced in YN7. However, 6‐BA application enlarges the starch granule size of both hybrids under drought conditions. Under both water conditions, 6‐BA application increases the proportion of high‒molecular weight amylopectin branch chains in both hybrids. The amylopectin chain‐length and relative crystallinity in response to 6‐BA application are dependent on hybrid and water condition. The pasting viscosities of both hybrids are improved by 6‐BA application under well‐watered conditions. However, the peak viscosity under drought is improved in JKN2000 and unaffected in YN7 by 6‐BA application. Under drought, 6‐BA application does notaffect the gelatinization characteristics but decreases the retrogradation enthalpy and percentage of both hybrids. In conclusion, exogenous 6‐BA application at the silking‐stage can improve the pasting viscosities under well‐watered conditions and reduce the retrogradation percentage under drought conditions, thereby alleviating the negative influence of post‐silking drought in waxy maize production.

Effects of warming on starch structure, rice flour pasting property, and cooked rice texture in a double rice cropping system

AbstractBackground and objectivesClimate warming has significant effects on rice quality. However, the effects of warming on starch structure, rice flour pasting properties, and cooked rice texture are unclear in double rice cropping systems. Therefore, a free‐air temperature increase experiment was conducted with two indica rice cultivars. The objectives of this study were to explore the changes in rice flour pasting properties and cooked rice texture under warming conditions and their relationships with starch structures.FindingsUnder warming conditions, rice starch had a lower amylose content (Peak 3) and proportion of long amylopectin branch chains (B3 chains) but a higher proportion of short amylopectin branch chains (A chains and B1 chains), amylopectin branching degree, relative crystallinity, ratio of 1045/1022 cm−1, and swelling power. Compared to the control treatment, warming significantly increased the peak viscosity, breakdown, and pasting temperature but decreased the setback of rice flour. Moreover, the hardness of cooked rice was significantly decreased, while its stickiness was significantly increased under warming conditions.ConclusionsThe changes in starch molecular structures resulted in lower hardness and setback but a higher stickiness, peak viscosity, breakdown, and pasting temperature of cooked rice or rice flour, which means better eating quality and worse cooking quality of double‐cropped indica rice under climate warming conditions.Significance and noveltyThese findings are expected to provide important information for improving rice cooking and eating quality and developing the rice industry under future climate warming conditions.

Investigation of physico-chemical properties of native and gamma irradiated starches

Starch is one of the most abundantly found carbohydrates in cereals, roots, legumes and fruits located in amyloplasts of plants. Native starch comprises of amylose, a linear α-glucan with α-1,4-linkage and amylopectin, a branched polysaccharide with both α-1,4-linkage and α-1,6-linkage. In food industries, the native starch is modified to manufacture the desired quality of starchy foods by means of physical, chemical, and enzymatic modification techniques. Gamma irradiation technique is one among the physical modifications of starch which is extensively used for the modification of native starch as it is rapid, less toxic and cost-effective technique. When starch is radiated with gamma rays, it is observed to produce free radicals owing to cleavage of amylopectin branches and exhibit variation in their physicochemical properties. In this study, commercially available corn, rice, and potato starch were irradiated with 10 kGy dose of gamma radiation and changes in their physicochemical properties were investigated. Native and irradiated starch was subjected to enzymatic hydrolysis with bacterial α-amylase (150 U/mL). The highest starch hydrolysis was observed for irradiated rice starch (17.03%). Amylose content of irradiated starch decreased by 3–4 %. The optical microscopic images showed the surface erosions of the irradiated starch and differential scanning calorimeter (DSC) revealed the thermal transition temperatures. Overall, starch hydrolysis and amylose content showed inverse correlation between them. Further studies regarding the effect of storage on gamma irradiated starch can help to gain new insights into the usage of modified starches in the manufacture of processed foods.

Yield, Grain Quality, and Starch Physicochemical Properties of 2 Elite Thai Rice Cultivars Grown under Varying Production Systems and Soil Characteristics.

Rice production systems and soil characteristics play a crucial role in determining its yield and grain quality. Two elite Thai rice cultivars, namely, KDML105 and RD6, were cultivated in two production systems with distinct soil characteristics, including net-house pot production and open-field production. Under open-field system, KDML105 and RD6 had greater panicle number, total grain weight, 100-grain weight, grain size, and dimension than those grown in the net-house. The amounts of reducing sugar and long amylopectin branch chains (DP 25–36) of the RD6 grains along with the amounts of long branch chains (DP 25–36 and DP ≥ 37), C-type starch granules, and average chain length of the KDML105 were substantially enhanced by the open-field cultivation. Contrastingly, the relative crystallinity of RD6 starch and the amounts of short branch chains (DP 6–12 and DP 13–24), B- and A-type granules, and median granule size of KDML105 starch were significantly suppressed. Consequently, the open-field-grown RD6 starch displayed significant changes in its gelatinization and retrogradation properties, whereas, certain retrogradation parameters and peak viscosity (PV) of KDML105 starches were differentially affected by the distinct cultivating conditions. This study demonstrated the influences of production systems and soil characteristics on the physicochemical properties of rice starches.

Effect of twin-xuscrew extrusion combined with cold plasma on multi-scale structure, physicochemical properties, and digestibility of potato starches

The influence of twin-screw extrusion (TSE), cold plasma (CP, 1, 5, and 9 min), and their combination (TSE-CP) treatment on the structural, physicochemical, rheological, solubility, and in vitro digestive properties of potato starches were studied. The results showed that CP slightly changed the starch granules morphology, maintained the growth ring and crystalline structure, promoted depolymerization of the amylopectin branch chain, and increased crystallinity and the ΔH value. It is worth noting that the resistant starch content increased from 84.80 to 86.46% in the short time CP modified potato starch. Meanwhile, TSE and TSE-CP treatments influenced surface morphology, growth ring of potato starch significantly. However, the dually modified potato starch using combined TSE and CP treatments promoted depolymerization of longer chains, increased the proportion of shorter chains and solubility, and improved the degree of hydrolysis. Furthermore, the single and dual treatments did not change the FT-IR spectra pattern. This study suggests that the combination between TSE and CP had more profound modification than the single treatment. The TSE combined with CP is an eco-friendly, thermal, and non-thermal combination technology, which can improve the multi-scale structure of starch and enhance physicochemical properties. Also, the dual treatment can be used to produce modified starch for industrial applications.

Modification of structural and physicochemical properties of cowpea (Vigna unguiculata) starch by hydrothermal and ultrasound treatments

Cowpea (Vigna unguiculata) starch was physically modified by heat moisture treatment (HMT) or HMT followed by ultrasound treatment (UST). The modifications of starch crystallinity, morphology and digestibility as well as thermal, and pasting characteristics were evaluated. HMT was performed at 20% moisture content, for 2, 5 and 12 h at 100 °C (HMT2, HMT5, HMT12). UST was performed at 80% amplitude (20 kHz) for 30 min (2 s on-2 s off). The granule shape and XRD patterns were not modified by any of the applied treatments. 1H NMR revealed that HMT and HMT-UST caused a decrease of amylopectin branching degree. Thermal stability increased more in heat-moisture-treated-starch, while gelatinization enthalpy was not affected by the treatments applied. The resistant starch content increased up to 11% with HMT, whereas an increase in slow digestible starch (SDS) (+30%) was observed in HMT2-UST and HMT5-UST. The decrease in pasting viscosity of treated starch samples increased incrementally with heating time. The results demonstrate that HMT and HMT-UST expand the opportunities and potential of using modified cowpea starches as ingredients in several food applications.

Preparing potato starch nanocrystals assisted by dielectric barrier discharge plasma and its multiscale structure, physicochemical and rheological properties

Non-thermal plasma has increasingly been used for surface modification of various materials as a novel green technology. In this study, we prepared potato starch nanocrystals (SNCs) assisted by dielectric barrier discharge plasma technology and investigated its multiscale structure, physicochemical properties and rheology. Plasma treatment did not change the morphology and crystalline pattern of SNCs but reduced the crystallinity. The amylose content, swelling power, gelatinization temperature, and apparent viscosity of SNCs decreased after the plasma process by depolymerizing the amylopectin branch chains and degrading SNCs molecules. Besides, plasma increased the rapidly digestible starch and resistant starch content. Changes in rheological properties of plasma treated SNCs suggested that the plasma process increased the flowing capacity. The effective structural and functional changes of plasma treated SNCs confirm that plasma technology has great potential for modification of SNCs.

Modification of multi-scale structure, physicochemical properties, and digestibility of rice starch via microwave and cold plasma treatments

The effects of microwave (MW) treatments for 30 and 90 s or cold plasma (CP) treatments for 2, 6, and 10 min on structural, physicochemical, and digestive properties of rice starch were investigated and compared with the effects of combined MW and CP treatments. Dual modification of starch using combined MW and CP treatments significantly changed starch granules' morphology, and starch showed lower crystallinity, swelling power, and peak viscosity than rice starch with a single modification. However, no significant changes were found in rice starch's crystalline structure and FT-IR spectra pattern after single or combined treatments. Effects of these treatments on the amylopectin branch chain length distribution and molecular weight of rice starch varied considerably depending on treatment type and treatment duration. Moreover, the dually modified rice starch contained more great content of resistant starch. Thus, the synergistic effects between MW and CP had more profound modification than the single treatment. Also, the dual treatment can be used to produce modified starch for industrial applications.

Structural characteristics and physicochemical properties of starches from winter squash (Cucurbita maxima Duch.) and pumpkin (Cucurbita moschata Duch. ex Poir.)

Winter squash (Cucurbita maxima Duch.) and pumpkin (Cucurbita moschata Duch. ex Poir.) are widely consumed in the world. Empirical evidences showed that their cooked texture was related to the starch content and probably starch properties. In this study, starches were extracted from 2 winter squash cultivars (Yinli and Heili) and 1 pumpkin cultivar (Miben) popularly cultivated in China. The mature fruits of three cultivars contained 1.05–6.47% (fresh weight) starch with different granule sizes (d (0.5) 9.51–15.18 μm). Starches from winter squash and pumpkin had polyhedral and spherical shape granules with amylose content varied from 21.35% to 30.17%. All starches exhibited B-type crystalline structure. The relative crystallinity ranged from 26.15% to 31.31%, and the IR absorbance ratios of 1022/995 cm−1 and 1045/1022 cm−1 ranged from 0.759 to 0.806 and from 0.565 to 0.607, respectively, among 3 cultivars. SAXS pattern indicated 9.59–9.80 nm DBragg for these starches. The Mw was highest (5.03 × 107 g/mol) in Miben starch but lowest (3.64 × 107 g/mol) in Heili starch. All starches had identical amylopectin branch chain distributions but varied in average chain length and fb1 and fb2 chains. The gelatinization temperature (To, Tp, Tc) and enthalpy change (ΔH) were lowest in Heili starch and highest in Miben starch. The peak, trough, final and setback viscosities varied from 4468 to 6266 cP, 3116 to 4259.5 cP, 4075 to 6073 cP, and 787 to 1813 cP, respectively. All starch granules showed strong resistance to enzymatic hydrolysis. Yinli and Miben starches had higher RS content in starch pastes and retrograded gels than Heili starch.

Effects of treatment methods on the formation of resistant starch in purple sweet potato

In order to determine the mechanisms underlying resistant starch formation, three treatments were used to prepare resistant starch from purple sweet potato. The resistant starch yield, amylose content, chain length distribution, thermal properties, and crystal structure were determined, and the results were compared with those of unmodified starch. Autoclaving, pullulanase, and pullulanase-autoclaving treatments significantly increased the resistant starch yield, amylose content, shorter amylopectin branch content, and gelatinisation temperatures of native purple sweet potato starch. Resistant starch prepared via pullulanase-autoclaving combination treatment exhibited the highest gelatinisation enthalpy value and the greatest degree of overall thermal stability. X-ray diffraction patterns and Fourier-transform infrared spectra analysis demonstrated that all three treatments transformed the starch crystalline structure from C-type to B-type, and no new groups were generated during the modification process; all the processes were only physical modifications.

Active-type starch synthase (SS) IIa from indica rice partially complements the sugary-1 phenotype in japonica rice endosperm.

Introduction of higher SSIIa activity to mild-type isa1 mutant by crossing results in restoration of crystallinity, starch granule structure, and production of plump seeds. Isoamylase 1 (ISA1) removes improper α-1, 6 glycosidic branches of amylopectin generated by starch branching enzymes and is essential for the formation of proper amylopectin structure. Rice isa1 (sug-1) mutants in japonica cultivar with less-active starch synthase IIa (SSIIa) and low granule-bound SSI (GBSSI) expression display wrinkled seed phenotype by accumulating water-soluble phytoglycogen instead of insoluble amylopectin. Expression of active SSIIa in transgenic rice produced with a severe-type isa1 mutant accumulated some insoluble glucan with weak B-type crystallinity at the periphery of seeds but their seeds remained wrinkled. To see whether introduction of high levels of SSIIa and/or GBSSI can restore the grain filling of the mild-type sug-1 mutant (EM653), new rice lines (SS2a gbss1L isa1, ss2aL GBSS1 isa1, and SS2a GBSS1 isa1) were generated by crossing japonica isa1 mutant (ss2aL gbss1L isa1) with wild type indica rice (SS2a GBSS1 ISA1). The results showed that SS2a gbss1L isa1 and SS2a GBSS1 isa1 lines generated chalky plump seeds accumulating insoluble amylopectin-like glucans with an increase in DP 13-35, while ss2aL GBSS1 isa1 generated wrinkly seeds and accumulated soluble glucans enriched with DP < 13. Scanning electron microscopic observation of cross-section of the seeds showed that SS2a gbss1L isa1 and SS2a GBSS1 isa1 produced wild type-like polygonal starch granules. These starches showed the A-type crystallinity comparable to the wild type, while the japonica isa1 mutant and the transgenic rice do not show any or little crystallinity, respectively. These results indicate that introduction of higher SSIIa activity can mostly complements the mild-type sug-1 phenotype.

Microcalorimetric investigation of amylopectin branching and the content of amylose in potato starches

Hydroxyethylated starches are of particular interest for applications in infusion therapy because of their high volemic effect. The duration of this effect depends on the circulation time of the drug in the blood, i.e., the volume of circulating blood increases with an increase in the concentration, molecular weight and degree of polymer substitution. It is known that hydroxyethylated starches have a wide range of molecular weight and degree of substitution. This allows their solutions to circulate for a long time (up to 10 hours) in the bloodstream without leakage of the active substance into the interstitium of vital organs. The dependence of the melting point of the crystalline starch lamella on the number of glucose residues can be described using the modified Fox - Loshaek ratio, which takes into account the degree of branching of amylopectin molecules and the content of amylose in starch. We proposed an analytical expression for the evaluation of the degree of branching of amylopectin from potato starch based on microcalorimetric data. The proposed methodology allows the genotypes of potatoes with the highest degree of amylopectin branching and a minimum quantity of amylose in starch to be selected. Starches of such potato varieties can be used in the blood plasma substitutes production - hydroxyethylated starches that have good pharmacodynamic properties. Within the developed approach, it is possible to determine the effect of the degree of substitution on the thermodynamic properties of the studied starches through a change in the melting temperature of the lamella, Tm, hence estimating the main pharmacodynamic parameters of substituted starches.

Structure and Properties of Starch in Rice Double Mutants Lacking Starch Synthase (SS) IIa and Starch Branching Enzyme (BE) IIb.

Starch biosynthetic enzymes form multi-protein complexes consisting of starch synthase (SS) I, SSIIa, and starch branching enzyme (BE) IIb, which synthesize amylopectin clusters. This study analyzed the starch properties in two double mutant rice lines lacking SSIIa and BEIIb, one of which expressed an inactive BEIIb protein. The ss2a be2b lines showed similar or greater seed weight than the be2b lines, and plant growth was not affected. The ss2a line showed increased short amylopectin chains resulting in a lower gelatinization temperature. Starch granule morphology and A-type crystallinity were similar between the ss2a line and the wild type, except for a mild chalky seed phenotype in the ss2a line. However, the starch phenotype of the ss2a be2b lines, which was similar to that of be2b but not ss2a, was characterized by increased long amylopectin chains, abnormal starch granules, and B-type crystallinity. The similarity in phenotype between the ss2a be2b and be2b lines may be attributed to the inability of the be2b mutants to generate short amylopectin branches, which serve as primers for SSIIa. Therefore, the presence or absence of SSIIa hardly affected the amylopectin structure under the be2b background. The amylose content was significantly higher in the ss2a be2b lines than in the be2b lines. Starch crystallinity was greater in ss2a be2b lines than in be2b lines, despite the fact that starch crystallinity is generally negatively correlated with amylose content. This suggests that the formation of a double helix between long amylopectin chains and amylose affects starch crystallinity in the ss2a be2b mutants.

Effects of superheated steam on starch structure and physicochemical properties of buckwheat flour during storage

This study showed that superheated steam (SS) processing could inhibit the changes in physicochemical properties of buckwheat during storage by altering the molecular structure of starch. The relationship between the molecular structure of starch (granular morphology, chain-length distribution, molecular weight, and long- and short-range structures) and the physicochemical properties (swelling power, water solubility, thermal properties and pasting properties) of flour and starch were investigated. The results showed that the water solubility, onset temperature (To), gelatinization enthalpy (ΔH), and pasting viscosity (peak, trough, and final) of untreated buckwheat flour decreased during storage, while the gelatinization temperature range (Tc–To) increased significantly (P < 0.05). SS processing restricted these changes in the physicochemical properties based on the results of the less reduction in relative crystallinity and 1047/1022 cm−1 ratio of starch. Furthermore, SS processing increased the mobility and reassembly of starch chains, narrowed the amylopectin branch chain-length distribution, reduced the heterogeneous molecular weight distribution, and increased the thermal stability of starch. Consequently, fewer changes were evident in the ΔH and breakdown value of the buckwheat flour during storage. Pearson's correlation analysis verified the relationship between the physicochemical properties of the buckwheat flour and the SS-induced changes in the starch molecular structure.

A current review of structure, functional properties, and industrial applications of pulse starches for value-added utilization.

Pulse crops have received growing attention from the agri-food sector because they can provide advantageous health benefits and offer a promising source of starch and protein. Pea, lentil, and faba bean are the three leading pulse crops utilized for extracting protein concentrate/isolate in food industry, which simultaneously generates a rising volume of pulse starch as a co-product. Pulse starch can be fractionated from seeds using dry and wet methods. Compared with most commercial starches, pea, lentil, and faba bean starches have relatively high amylose contents, longer amylopectin branch chains, and characteristic C-type polymorphic arrangement in the granules. The described molecular and granular structures of the pulse starches impart unique functional attributes, including high final viscosity during pasting, strong gelling property, and relatively low digestibility in a granular form. Starch isolated from wrinkled pea-a high-amylose mutant of this pulse crop-possesses an even higher amylose content and longer branch chains of amylopectin than smooth pea, lentil, and faba bean starches, which make the physicochemical properties and digestibility of the former distinctively different from those of common pulse starches. The special functional properties of pulse starches promote their applications in food, feed, bioplastic and other industrial products, which can be further expanded by modifying them through chemical, physical and/or enzymatic approaches. Future research directions to increase the fractionation efficiency, improve the physicochemical properties, and enhance the industrial utilization of pulse starches have also been proposed. The comprehensive information covered in this review will be beneficial for the pulse industry to develop effective strategies to generate value from pulse starch.

Characterization of gluten-free rice bread prepared using a combination of potato tuber and ramie leaf enzymes.

A combination of freeze-dried powder of disproportionating enzyme (D-enzyme)-containing potato tuber and β-amylase-containing ramie leaf was used to improve the gluten-free (GF) bread, and its physicochemical properties were characterized. The presence of D-enzyme and β amylase in the potato tuber and ramie leaf was confirmed. Sixty five percent of partially gelatinized rice flour and 20% corn starch was combined with 10% freeze-dried potato tuber and 1% ramie leaf powder, and baked. The specific volume increased by 23% compared to the control with improved internal characteristics. Texture profile analysis revealed that retrogradation of the bread was retarded when stored for 90h at 4°C. The bread crumb amylose content was reduced from 14 to 9% and amylopectin branch chain-length distribution was rearranged, whereby the proportions of the branch chains with Degree of polymerization (DP) < 9 and DP > 19 decreased. The results suggest that D-enzyme and β-amylase cooperatively altered amylose/amylopectin ratio and amylopectin structure.