Increase In Amylose Content Research Articles

Preparation and characterization of non-crystalline granular starch with low processing viscosity

Non-crystalline granular starch (NCGS) has advantages in the deep processing of starch owing to its unique structure and function. In this study, NCGS was successfully prepared at a baking temperature of 210 °C, and the morphology, structure, pasting properties, and rheological properties of the NCGS were systematically studied. Compared with native starch, NCGS showed a lower processing viscosity and rapid reduction in the peak viscosity from 3795 to 147 cP. Furthermore, NCGS exhibited impaired short- and long-range ordered structures, as indicated by the lower ratio of absorbance at 1047/1015 cm−1 and decreased crystallinity compared to native starch. Additionally, amylose and amylopectin with long and medium chains in NCGS were degraded into short chains, resulting in an increase in amylose content and branch density. The analysis of the physicochemical properties of NCGS, especially the low processing viscosity, is of great importance for the industrial application of starch, particularly in terms of improving the yield, saving energy, and reducing environmental pollution.

Effect of Genetic Modification of Maize Plant on Pharmaceutically Important Properties of Its Starch

Genetic engineering of maize plants for improved yield, drought and pest resistance has received considerable attention in agricultural research. The aim of this work is to determine the effect of genetic modification of maize plant on some pharmaceutically relevant fundamental properties of its isolated starches. Properties of starches isolated from PVA 39 and IWD 15 maize genotypes were compared with starch from unmodified maize grains. Morphology studied by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) were evaluated. Swelling capacity, amylose content, pasting behaviour of the starches were also determined. SEM revealed that all the starches are largely irregular and polygonal with few round shaped granules. FTIR showed identical peaks in all the starch samples and DSC revealed higher enthalpies of starch gelatinisation from the modified grains. Modification also increased amylose content, swelling capacity and viscosity of the starches. Genetic modification increased amylose content which positively affected pharmaceutically important properties like moisture sorption and viscosity, thus, increasing their value in formulations especially as binders.

Starch synthases SSIIa and GBSSI control starch structure but do not determine starch granule morphology in the absence of SSIIIa and SSIVb.

High levels of two major starch synthases, SSIIa and GBSSI, in ss3a ss4b double mutant rice alter the starch structure but fail to recover the polygonal starch granule morphology. The endosperm starch granule is polygonal in wild-type rice but spherical in double mutant japonica rice lacking genes encoding two of the five major Starch synthase (SS) isozymesexpressed in endosperm, SSIIIa and SSIVb. Japonica rice naturally has low levels of SSIIa and Granule-bound SSI (GBSSI). Therefore, introduction of active SSIIa allele and/or high-expressing GBSSI allele from indica rice into the japonica rice mutant lacking SS isozymes can help elucidate the compensatory roles of SS isozymes in starch biosynthesis. In this study, we crossed the ss3a ss4a double mutant japonica rice with the indica rice to generate three new rice lines with high and/or low SSIIa and GBSSI levels, and examined their starch structure, physicochemical properties, and levels of other starch biosynthetic enzymes. Lines with high SSIIa levels showed more SSI and SSIIa bound to starch granule, reduced levels of short amylopectin chains (7 ≤ DP ≤ 12), increased levels of amylopectin chains with DP > 13, and consequently higher gelatinization temperature. Lines with high GBSSI levels showed an increase in amylose content. The ADP-glucose content of the crude extract was high in lines with low or high SSIIa and low GBSSI levels, but was low in lines with high GBSSI. Addition of high SSIIa and GBSSI altered the starch structure and physicochemical properties but did not affect the starch granule morphology, confirming that SSIIIa and SSIVb are key enzymes affecting starch granule morphology in rice. The relationship among SS isozymes and its effect on the amount of substrate (ADP-glucose) is discussed.

Impact of long-term storage on multi-scale structures and physicochemical properties of starch isolated from rice grains

Rice short-term (less than 12 months) storage significantly affected starch structures and physicochemical properties, and in turn, influenced rice functionalities. However, effects of rice long-term (more than 12 months) storage on starch structures and functionalities have been not resolved yet. This study revealed the changes in structures and physicochemical properties of starch during rice long-term storage (12–36 months). Rice storage resulted in degradation of starch molecules, which increased amylose content and reduced the content of long branch-chains of amylopectin, double helices, short-range ordered structures, crystalline structures, and lamellar ordering degree along with apparent erosion of starch granules. Those structural changes significantly increased starch thermostability, favored starch short-term reassociation, and promoted starch enzymatic digestion. Comparing with the short-term storage (1 year of storage), the long-term storage (2 or 3 years of storage) yielded a more serious degradation on starch multi-scale structures, and in turn, resulted in a higher thermostability, and better-defined gel structures and higher starch digestion extent after cooking and cooling. Compared with the short-term aged rice, the long-term aged rice is a better candidate to prepare rice-based gel-like foods such as noodles. This study provided a promising pathway to control structures and physicochemical properties of rice starch and even rice-based foods via simply controlling rice-storage time.

Physicochemical and volatile characteristics present in different grain layers of various rice cultivars

Five rice cultivars were applied for investigating effect of milling degree on rice physicochemical properties. The first layer had the lowest peak viscosity, followed by the second and third layers, indicating the effect of non-starchy components on starch gelatinization behaviors. Consistently, more content of non-starch components in the first layer led to an enhanced gelatinization temperature. Rheological study demonstrated the G’ and G” were successively increased as the layer moved inward, indicating a stronger gel network due to the increased amylose content and crystallinity in the corresponding layer. This is the first study to reveal the second layer has the highest digestibility, suggesting both non-starch components and starch structure control starch digestion. Furthermore, analysis of volatile compounds found alcohols and ketones concentrated in the first layer, whilst compounds including (E,E)-2,4-decadienal, 3-octanone and 3-nonen-2-one only existed in the second layer, serving as an indicator for managing the rice quality during milling.

Characterization and digestogram modeling of modified elephant foot yam (Amorphophallus paeoniifolius) starch using ultrasonic pretreated autoclaving

AbstractNative elephant foot yam starch (EFYS) is highly digestible, and it is not recommendable for consumption by diabetic and obese people. To address this problem, the current study focuses on the amendments in various properties (such as functional properties, whiteness index, amylose content, morphology, and digestion) of EFYS using ultrasonication (US) and US pretreated autoclave (AL) modification with varied time viz. 15, 30, and 45 min. Both the treatments enhanced the water absorption, swelling power, and solubility of EFYS. US‐assisted AL treatment was responsible for increasing the resistant starch (RS) fraction and the highest increment was observed in US‐AL45 EFYS (39.13 ± 1.19 %) as compared to the native counterpart (30.65 ± 1.06 %). Molecular aggregations were observed in all US‐AL EFYS, whereas US treatment broke the agglomerations and increased the intergranular spaces. FTIR analysis revealed the highest increase in ordered to amorphous starch (1047/1022 cm−1) in US‐AL45 EFYS followed by native and others modified EFYS. The highest increase in amylose content was notable in US‐AL45 (10.02 ± 0.08 %) as compared to other native and others treated EFYS. To understand the kinetic behavior of the native and modified EFYS, first‐order kinetics, Michaelis–Menten, Paolucci Jeanjean, Logistic, and Weibull models were applied. The digestogram models highlighted the highest digestibility in native EFYS, preceded by US, US‐AL 15, US‐AL 30, and US‐AL 45 EFYS. US‐AL 45 EFYS showed the highest change in all the functional properties as compared to native and other modified EFYS.Practical applicationsOwing to the prevalent lifestyle diseases, a continuous evolution in nutritional behaviors has emerged. Although starch imparts consistency and quality to the commercial food products, its high digestibility results in harmful effects to diabetic and obese patients. Elephant foot yam is considered as a unique source of starch and its modification leads to a decrease in enzyme hydrolysis while making it health beneficial. Ultrasonic pretreated autoclaving is one such potential physical modification treatment which can facilitate toward decrease in enzyme digestibility of elephant foot yam starch (EFYS), yet enhancing its swelling properties that in turn leads to the growth of functional food processing industry. The findings of the study highlight the enzyme digestogram modeling of US and US‐AL modified EFYS in order to shed light on the mechanism that regulates them.

Ultrasound‐Assisted Extraction of Lychee (Litchi chinensis Sonn.) Seed Starch: Physicochemical and Functional Properties

AbstractHigh‐power ultrasound (HPU) is a non‐thermal processing method that has been researched and used in the last years. The application of ultrasound can modify and improve some technologically important compounds such as starch. This research aimed to examine the effect of ultrasound treatment on yield, physicochemical, and functional properties of lychee seed starch (LS). HPU experimental conditions used were sonication time (5 and 20 min) and amplitude (40% and 70% ). Starch yield significantly increased with increasing ultrasound amplitude and time. The ultrasound did not change the morphology and shape of the granules but caused cracks in their surface. Surface damage induced an increase in amylose content, relative crystallinity, enthalpy of gelatinization, swelling power, solubility index, and acid hydrolysis of the starch. These results indicate that ultrasound mainly affected the amorphous starch region. The morphology, size, color, rheological and thermal characteristics, crystal structure, and structural order features of the untreated and ultrasound‐treated LSs were compared. A principal component analysis was carried out to assess the effect of the ultrasound treatment on LS characteristics.

Functional and digestibility properties of sago (Metroxylon sagu) starch modified by microwave heat treatment

Sago starch is an underutilized starch due to its low functionality in the formulation of food products. Starch modification can enhance the functionality and functional food properties such as solubility and resistant starch content, respectively. The sago starch was treated by microwave heat treatment with two different pre-treatment which were washing (WMHT) or cold-soaking (SMHT). The modified starches exhibit better solubility in water (95 °C), oil and water binding capacity, and resistant starch (RS) content of cooked samples compared to its native. Additionally, an increase in amylose content and degree of double helix together with morphological changes on the starch granules (WMHT) were also observed. In conclusion, the changes in granules morphology and availability of amylose content by the treatments had influenced the improved some of the starch functionality and RS content. Further study is required to determine the potential of the modified starch as a low glycaemic food ingredient.

Characterization of molecular, physicochemical, and morphological properties of starch isolated from germinated highland barley

Germination is a non-chemical and simple approach usually used to improve the bio-availability of crucial nutrients. In this study, the effect of germination on molecular, physicochemical, morphological properties of highland barley starch was investigated. The results of this study revealed that germination for 72 h (GB72) significantly increased amylose content and gelatinization temperatures (To and Tc) to 26.3%, 59.79 °C, and 68.19 °C as compared to 22.81%, 57.56 °C, and 67.05 °C in native barley starch (NB), respectively, and a significant decrease in total starch contents was noticed (31.67%) in GB72 as compared to 45.70% in NB. After germination, the FT-IR intensity ratio of 995/1022 and 1047/1022 bands, pasting temperatures, particle size, and swelling capacity were also decreased. Moreover, average molecular-weight, relative crystallinity, gelatinization temperature ranges, and enthalpy of gelatinization were decreased as compared to NB starch, and the decrease was more obvious in GB72 starches (0.49 × 108 g/mol, 17.64%, 8.40 °C, and 6.41J/g), respectively. This study indicates the effectiveness of germination for the modification of highland barley starch and its potential to enhance starch-based products.

Effect of molecular structure on phase transition behavior of rice starch with different amylose contents

Phase transition behaviors in starch-water system and molecular structures of rice starches isolated from four Korean cultivars with different amylose contents were investigated and the importance of structural features affecting starch phase transitions was also explored. The Dodam starch with the highest average chain length of amylopectin (26.1), the highest proportion (24.3 %) of long chains (DP ≥ 37), and the lowest proportion (17.5 %) of short chains (DP 6-12) displayed the highest gelatinization and retrogradation temperatures. Enthalpies of ice freezing and melting, and glass transition temperature (Tg′) of rice starches increased with increasing amylose content and decreasing proportion of short amylopectin chains because these structural features are related to a higher thermal stability of the starches. Ice melting temperature was also influenced by amylopectin chain structures. The results suggest that the phase transition behaviors of rice starches were highly influenced by their amylose content and amylopectin chain length distribution.

Structural, pasting and sensory properties of rice from main and ratoon crops

ABSTRACT Ratooning was a practical approach to increase the grain yield of rice. In this research, main and ratoon crop rice were compared in quality attributes, including composition, starch morphology, starch crystalline structure, protein components, pasting property, texture, and sensory attributes of cooked rice. As compared to main crop rice, ratoon crop rice showed an increase in amylose content and a decrease in protein content. Both main and ratoon crop rice starches exhibited similar polyhedral shape and A-type crystalline structure, but the ratoon crop rice had a lower relative crystallinity. Globulin content of ratoon crop rice protein was higher than that of main crop rice protein. As compared to main crop rice flour, ratoon crop rice flour showed a decrease in pasting temperature, peak viscosity, and breakdown viscosity but an increase in final viscosity and setback viscosity. After cooking, ratoon crop rice had higher hardness, cohesiveness, gumminess, and resilience than main crop rice. In sensory evaluation conducted with trained panelists, ratoon crop rice scored higher than main crop rice in overall acceptance.

Physicochemical and rheological properties and in vitro digestibility of heat moisture treated and annealed starch of sohphlang (Flemingia vestita) tuber

The effect of heat moisture treatment (HMT) and annealing (ANN) on physicochemical and rheological properties and in vitro digestibility of starch extracted from sohphlang (Flemingia vestita) was studied. Modification by HMT and ANN increased amylose content and water absorption capacity. For all modified samples, solubility, swelling power and amylose leaching progressively increased with increasing temperature (50–90 °C). Modified starches exhibited higher contents of SDS and RS and lower content of RDS as compared to native starch for both cooked and uncooked samples. The rheological properties of starch pastes were investigated by the power law model. The starch paste samples exhibited shear thinning characteristics and phase angle was closer to 0°. HMT-30 and ANN-80 exhibited greater impact on in vitro digestibility and rheological behaviour among the HMT and ANN starches, respectively. Thus, ANN and HMT could be used for modification of sohphlang starch making them suitable for application in food systems like pasta and noodles.

Insights into the structural characteristics and in vitro starch digestibility on steamed rice bread as affected by the addition of okara

Starch structure and digestibility strongly depends on food composition during rice bread processing. This study investigates the effect of okara (0%, 7%, 14%, 21%) on the texture, in vitro starch digestibility, and multiscale structure (i.e. granule, crystallites, and short-range order) of steamed rice bread (SRB). Texture profile analysis results demonstrated that okara increased the elasticity and viscidity and reduced the hardness, cohesiveness, and chewiness of SRB. The addition of okara increased amylose content, slowly digestible starch (SDS), and resistant starch (RS) of SRB significantly, thereby reducing the predicted glycemic index (pGI) from 79.14 to 74.17–68.91. Meanwhile, SEM results showed that addition of 7% okara promoted the formation of the porous space starch–gel network structure in the SRB while 21% okara produced rougher surfaces and increased bread matrix density. XRD and FTIR revealed that suitable amounts of okara (<14%) assisted in starch arrangement while others (21%) reduced the ordered crystallization of starch. Results showed that the enhanced intermolecular hydrogen bonding between okara and water enhanced the viscosity and gas retention of SRB, thereby enabling the starch to retain more gas and form a loose starch gel structure spatial network. Furthermore, the addition of okara changed the multiscale structural and amylose contents when the SDS and RS contents are high and the pGI is low. As a result, the action sites of amylase can be shielded effectively to restrict the interaction of amylase with starch. Thus, this research suggests a potential approach in which rice complexed with okara can modify the texture and starch digestibility of SRB.

Polyurethane prepolymer-modified high-content starch-PBAT films

We report a modified starch-poly(butylene adipate co-terephthalate) (PBAT) film (MSPF) prepared by extrusion blowing. Polyurethane prepolymer (PUP), was modified to the starch to enhance the compatibility. Different contents of amylose was blended with PBAT for improving mechanical strength and oxygen-barrier properties of MSPF. The microstructures, crystallinity, mechanical properties, oxygen-barrier capacity of MSPF were thoroughly evaluated. The result showed that MSPF with high starch content and excellent performances was successfully prepared with the synergy of PUP modification, amylose introduction and extrusion blowing. The crystallinity, hydrophobicity, oxygen-barrier properties and mechanical properties of MSPF increased with the increasing amylose content. The maximum tensile strength and elongation at break of MSPF reached 10.6 MPa and 805.6 %, respectively, even at the high starch content of 50 %. The result demonstrated that MSPF having excellent mechanical properties and oxygen-barrier properties could be use in the biodegradable field such as packaging materials, agricultural films and garbage bags.

13C CP/MAS NMR Can Discriminate Genetic Backgrounds of Rice Starch

Solid-state cross-polarization magic-angle spinning carbon-13 nuclear magnetic resonance (13C CP/MAS NMR) spectroscopy is used to analyze starch derived from plants including wheat, maize, and potato, but few reports have described its application to rice starch. Here, we combined 13C CP/MAS NMR with deconvolution and subtraction methods to analyze rice lines including mutants that are deficient in at least one enzyme involved in amylose and/or amylopectin biosynthesis. We found that differences in the content of ordered structures between rice lines could be evaluated using C1 signal deconvolution and subtraction. The content of the V-type ordered structure increased with increasing amylose content. Furthermore, starch derived from a starch synthase (SS) IIIa/starch branching enzyme (BE) IIb-deficient mutant formed B- and V-type ordered structures and significantly more nonordered structures than the other rice lines. These data indicate that 13C CP/MAS NMR analysis is useful for discriminating the genetic backgrounds of starch derived from different rice cultivars.

Effect of starch microstructure on microwave-assisted esterification

Dry modification of starch, especially by microwave-assisted heating, has attracted increasing attention due to its various advantages, including energy saving, high conversion, rapidity, and avoidance of volatile organic solvents in organic synthesis. This work focuses on two fundamental issues: 1) effect of starch microstructure on dry modification; 2) effect of acid anhydride in solid and liquid states on the dry reaction, since their interfaces with solid starch are significantly different. Cornstarches with different amylose/amylopectin ratios were used to demonstrate the effect of starch microstructure, while two acid anhydrides, maleic (solid) and acetic (liquid) anhydrides, were used to study the reaction mechanisms. FTIR, SEM, XRD, and DSC were used to study the performance of modified starches and the mechanisms. It was found that the degree of substitution (DS) of starches modified by maleic anhydride generally increased with increasing amylose content since amylose contains more hydroxyl groups, resulting in higher sensitivity to microwaves. On the other hand, the DS of starches modified by acetic anhydride increased with increasing amylopectin content, since liquid acetic acid can diffuse into high-amylopectin starch granules. The higher amylopectin starches, waxy and maize, showed higher RC(%) and ∆H(%) than that of higher amylose starches G50 and G80.

쌀 품종 및 옥수수 배합비율에 따른 팽화스낵의 품질 특성

In order to increase the usability of rice, this study was investigated the quality characteristics of extruded rice snacks based on the rice cultivar (‘Aromi’, ‘Hanahreum’, ‘Jasmin 85’ and ‘Bukkyeong 2012’) and ratio of corn flour (0, 30, 50, 70 and 100% w/w) to rice flour. The moisture content and bulk density decreased as the amylose content decreased, whereas the porosity and expansion ratio tended to decrease with increasing amylose content. The strength and hardness increased significantly with the amylose content. The water solubility index and water absorption index decreased and increased, respectively, as the amylose content increased. The moisture content and the L value increased significantly as the proportion of rice flour was increased, whereas the b value decreased significantly. The bulk density increased with increasing rice flour content. The porosity, expansion ratio and specific length tended to increase as the amount of rice flour was increased. The strength and hardness were the lowest in extruded snacks made with 70% of rice flour. The water solubility index and water absorption index increased significantly with increasing rice flour content. Therefore, the best quality characteristics were observed in extruded snacks made with the Aromi, and the optimal proportion of rice flour was 70%.

Effects of heat, drought and their combined effects on morphological structure and physicochemical properties of rice (Oryza sativa L.) starch

High temperature (HT) and drought stress (WS) severely affect rice quality by altering the starch structure in rice. The morphological and physicochemical properties of starches isolated from two rice varieties grown under three stress treatment (HT, WS and WS + HT) during the grain filling stage were investigated. The results showed that WS increased amylose content (AC%) and the proportion of large starch granules (LSG) and made the surface of the starch granule smooth and flat. As a result, a lower relative crystallinity, surface order, swelling power, setback viscosity and gelatinization enthalpy were caused. HT decreased AC% and milled rice rate, but increased chalky rice rate, the number of LSG and the large air space and pits on the surface of the starch granules. As a result, a higher relative crystallinity, surface order, swelling power, setback viscosity and gelatinization enthalpy were caused. Similar results were observed under the treatment of WS + HT, indicating that there is a mild antagonistic effect on rice starch when the HT and WS occur simultaneously.

Amylose content and specific fine structures affect lamellar structure and digestibility of maize starches

The molecular and lamellar structures and in vitro digestibility of high amylose maize starch granules were investigated. Size-exclusion chromatography (SEC) analysis of hydrodynamic radius (Rh) and relative contents (RC) of different amylose and amylopectin pools revealed that increased amylose content resulted in the decrease of RC of short amylopectin chains (AP1, DP < 36), and the increase of Rh and RC of long amylopectin chains (AP2, DP > 36). Fluorophore-assisted carbohydrate electrophoresis (FACE) analysis showed the average chain lengths of defined structures of fa, fb1, and fb3, and the content of fb3 were increased with the amylose content and at AC content of 43%, the chain lengths decreased with the amylose content. The relative contents of fa and fb1and the degree of branching had the converse trends. Hence, HA-2, having an AC content of 43%, was the tipping point for these structural changes. Small angle X-ray scattering (SAXS) and its normalized 1D correlation function and SAXS scattering curve parametric fitting showed that the crystalline lamellar thickness was negatively correlated with proportion of short amylose chains (AM1, 100 <DP ≤ 150). The Bragg lamellar repeat distance was positively correlated to Rh of the intermediate amylose chains (AM2, 150< DP ≤ 800). The amorphous lamellae thickness was positively correlated with the Rh of long amylose chains (AM3, 800 <DP ≤ 40,000). The positive correlation between Rh of AM2 on the Gaussian peak area and the scattering invariant suggests AM2 chains stabilize the lamellar structure. Both the digestion rate of the digestible starch as well as the resistant starch content were positively correlated with amylose content. Pearson correlation analysis demonstrated that longer amylopectin chains and lower content of AP1 chains were positively correlated with the digestion rate.

Microstructure and physicochemical characteristics of modified taro starch after annealing, autoclaving-cooling and heat moisture treatment

This study investigated the effects of annealing, autoclaving-cooling and heat moisture treatment on the microstructure and physicochemical characteristics of taro starch. The taro starch was treated by the annealing process (24 hrs, 50oC), the heat moisture treatment (HMT) (moisture 25%, 3 hrs, 110oC), and the autoclaving (15 mins, 121oC) - cooling (24 hrs, 4oC) with 1 and 2 cycles. The results show that the autoclaving-cooling 2 cycles (AC-2C) changed the microstructure of taro starch into a very compact and dense structure because of formed double helix bound that cannot be hydrolyzed by pancreatic enzymes so it can be converted became resistant starch as the prebiotic source. Pasting properties analysis showed that AC-2C improved shear stress resistance, heat resistance and low retrogradation modified taro starch (MTS). The AC-2C treatment increased water binding capacity (73.84%), solubility (44.58%), and swelling power (16.71%) of MTS. The water-binding capacity had a positive correlation with solubility and swelling power. The AC-2C treatment increased amylose content (27.40%) and decreased reducing sugar level (6.36%) of MTS, so it can encourage the formation of resistant starch to improve the prebiotic properties of taro starch. Modified taro starch AC-2C is the best compared to HMT and annealing based on microstructure and physicochemical characteristics.