Varying Amylose Content Research Articles

Mechanism of maltogenic α-amylase modification on barley granular starches spanning the full range of amylose

Amylopectin (AP)-only (APBS), normal (NBS), and amylose (AM) only (AOBS) barley starches were selected here to investigate catalysis pattern of maltogenic α-amylase (MA) on hydrolyzing AP and AM granular starches. MA shortened starch side chains with degree of polymerization (DP) 11–30. MA-treated APBS exhibited porous granular structures and dramatically increased degree of branching (DB, 17–20 %), and reduced ordered degrees, suggesting high hydrolysis and transglycosylation activities of MA. MA-treated NBS showed less pronounced porous structures and slightly increased DB (2–4 %), indicating high hydrolysis but low transglycosylation activities. AOBS displayed minimal changes in DB (0.2–0.3 %) and starch structures, implying low hydrolysis and transglycosylation activities. Therefore, MA preferred to attack the AP molecules with abundant glucan substrates with DP 11–30, while AM restricted MA activity likely by creating ineffective binding sites and undergoing rapid reorganization. These findings deepened the understanding of the mechanisms of MA in modifying granular starches with varying AM content.

Suitability of early indica rice for the preparation of rice noodles by its starch properties analysis

The research was conducted to explore the affiliation between the physicochemical properties of rice noodles and rice starch of early indica rice samples of varying amylose content. 3 various types of rice samples were analyzed to uncover how amylose content influences rice noodles' quality. Findings revealed that primarily sensory scores differ in palatability, while textural disparity lies in hardness and chewiness. The higher hardness and chewiness values were correlated with higher sensory scores. Rice with lower amylose content demonstrates elevated solubility, swelling power, and crystallinity along with poor retrogradation resulting in inferior-quality noodles. Sensory scores and textural properties were proved to be associated with the distribution of branched starch molecule chain lengths. Noodles of higher sensory scores had more stable gel structure and improved elasticity. These findings underscore the critical role of amylose content and starch molecular structure in determining the suitability of early indica rice for noodle preparation.

Structural and physicochemical characteristics of starches from sorghum varieties with varying amylose content.

Six sorghum varieties containing different amylose were selected to investigate the structural and physicochemical characteristics of starches and endosperm texture of grains. The results showed that the outer layer endosperm of sorghum grain changed from waxy to corneous, and its starch granules were more compactly packed and exhibited the spindle-shaped holes with the increase of amylose content. Higher amylose starch granules exhibited fewer and smaller micropores on the surface and were more likely to deform and agglomerate into larger amorphous particles after heated. Amylose content of sorghum starches was negatively correlated to granule size, relative crystallinity, and the proportion of the long branch chains (DP = 25-36 and > 36), whereas positively correlated to the proportion of the short branch chains (DP = 6-12 and 13-24). Amylose content had negative correlations with T o , T p , ΔH, PV, and SDS (p < .05), positive corrections with FV, SB, and RDS (p < .05), and no correlations with T c , HPV, BD, and RS. It could be concluded that amylose content affected the endosperm texture of sorghum grain and had strong correlations with structural and physicochemical properties of sorghum starch. These findings may help identify uses for these sorghum varieties in baijiu production.

Green, tough, and heat-resistant: A GDL-induced strategy for starch-alginate hydrogels

Hydrogels fabricated by non-covalent interaction garnered significant attention for their eco-friendly and robust mechanical attributes, and are often used in food, medicine and other fields. Although starch-alginate hydrogels exhibit high adhesion and are environmentally sustainable, their applications are limited due to their low elasticity and hardness. Addressing this challenge, we introduce a solvent-induced strategy using glucolactone (GDL) to fabricate hydrogels with enhanced strength and thermal resilience. Utilizing corn starch with varying amylose contents, sodium alginate and calcium carbonate to prepare a double network structure. This GDL-induced hydrogel outperforms most previous starch-based hydrogels in mechanical robustness and thermal stability. Typical starch-alginate hydrogel had a homogeneous network structure and exhibited a high tensile stress of 407.57 KPa, and a high enthalpy value of 1857.67 J/g. This investigation furnishes a facile yet effective method for the synthesis of hydrogels with superior mechanical and thermal properties, thereby broadening the design landscape for starch-based hydrogels.

Impact of soluble soybean polysaccharide on the gelatinization and retrogradation of corn starches with different amylose content

Polysaccharides have a significant impact on the physicochemical properties of starch, and the objective of this study was to examine the effect of incorporating soluble soybean polysaccharide (SSPS) on the gelatinization and retrogradation of corn starches (CS) with varying amylose content. In contrast to high-amylose corn starch (HACS), the degree of gelatinization of waxy corn starch (WCS) and normal corn starch (NCS) decreased with the addition of SSPS. The inclusion of SSPS resulted in reduced swelling power in all CS, and led to a decrease in gel hardness of the starches. The intermolecular forces between SSPS and CS were primarily hydrogen bonding, and a gel network structure was formed, thereby retarding the short-term and long-term retrogradation of CS. Scanning electron microscopy results revealed that the addition of SSPS in starches led to a loose network structure with larger poles and a reduced ordered structure after retrogradation, as observed from the cross-section of formed gels. These findings suggested that SSPS has great potential for applications in starchy foods, as it can effectively retard both gelatinization and retrogradation of starches.

Pasting Characteristics and In Vitro and In Vivo Digestibility of Low‐, Medium‐, and High‐Amylose Types of Mung Bean Flour after Heat‐Moisture Treatment

AbstractMung bean (Vigna radiata L.) flour varieties of varying amylose content are heat‐moisture treated at 100 °C for 6 h, and changes in their pasting properties and digestibility are investigated. Amylose content of the low‐amylose (LAM MB), medium‐amylose (MAM MB), and high‐amylose mung bean flour (HAM MB) is 16.1%, 23.2%, and 31.7%, respectively. Mung bean flour after heat‐moisture treatment (HMT) shows significantly reduced peak and breakdown viscosities and swelling power compared to those in native flours. However, pasting temperature, final and setback viscosities, and solubility of the mung bean flour significantly increase after HMT. The treated mung bean flour also contains higher amounts of resistant starch (RS, 19.6%–30.6%) than that in the corresponding untreated flour (14.9%–17.5%). Consequently, mung bean flour subjected to HMT induces a lower blood glucose response in mice and exhibits lower glycemic index (GI) values than that of untreated flour. Among all mung flour types subjected to HMT, the HAM MB exhibits the highest viscosity, solubility, and swelling power and has the highest RS content (30.64%), and the lowest blood glucose response and GI value. Thus, mung bean flour after HMT with desirable properties and digestibility can be used in the production of low‐carbohydrate foods.

Artificial intelligence classification and amylose content prediction of rice flour varieties from their pasting features

The pasting features of eight varieties of rice flour with varying amylose content were characterized and then subjected to machine learning analysis in order to classify the rice varieties and predict their amylose content. The waxy rice flour with the least amylose showed a peak viscosity in the early stage of heating, and the high amylose rice flours had the highest final viscosity. Principal component analysis showed that 87.2% of the total variability was explained by the two principal components, which were mainly related to peak temperature and final viscosity. When the pasting features were used as a machine learning dataset for classification, the support vector machine classifier was the most effective in correctly classifying the rice flour varieties by showing a high accuracy and F1-score, followed by the decision tree and stochastic gradient descent. In addition, the integration of pasting features with machine learning analysis showed the potential to predict the amylose content of rice flours. These prediction performances were confirmed by validating the models with independent datasets.

The interaction and physicochemical properties of the starch-polyphenol complex: Polymeric proanthocyanidins and maize starch with different amylose/amylopectin ratios

This study investigated the impact of polymeric proanthocyanidins (PPC) on the physicochemical characteristics of maize starch with varying amylose content, and their potential interaction mechanism. PPC with a lower content (1 %) reduced the viscoelasticity of the high amylose maize starch (HAM) system, inhibited amylose rearrangement, and enhanced its fluidity. However, excessive PPC restrained the interaction between PPC and amylose. In contrast to HAM, PPC improved the gelation ability of waxy maize starch (WAM) as PPC concentration was raised. PPC suppressed the recrystallization of starch during storage, and PPC had a superior inhibition influence on the retrogradation of WAM in comparison to HAM. This indicated that amylopectin was more likely to interact with PPC than amylose. Hydrogen bonds were the main driving force between PPC and starch chains, which was clarified by Fourier transform-infrared, nuclear magnetic resonance, X-ray diffraction, iodine bonding reaction, and dynamic light scattering data. Additionally, the mechanism of interaction between PPC and the two starch components may be similar, and variance in physicochemical attributes can be primarily credited to the percentage of amylose to amylopectin in starch.

Quality Characteristics of Rice-Based Ice Creams with Different Amylose Contents

Ice cream consumption has increased over the years. In this study, we investigated the potential of using rice varieties with varying amylose contents for ice cream production. We analyzed the physical and chemical properties and sensory quality characteristics (appearance, taste, texture, chewiness, aroma, and rice flavor) of rice-based ice cream made from five varieties with low and high amylose levels. To make the ice cream, we ground rice into a fine powder and combined it with skim milk powder, butter, sugar, glycerin esters of fatty acids, locust bean gum, and water to form a gelatinized mixture. This mixture was then aged, frozen, and hardened. The ice cream's key quality characteristics, such as viscosity (2170-25,030 cP), hardness (4.27-49.55 N cm-2), and overrun (17.95-46.99%), showed a wide range. Ice cream made from Saemimyeon (high amylose content rice variety) exhibited the highest hardness value (49.55 N cm-2) among the varieties tested, but had relatively low viscosity (4030 cP), overrun (17.95%), and drip-through (0.75 g/min) values. These findings suggest that rice varieties with different amylose contents are suitable for making ice cream and have the potential to expand the rice processing market and increase its value.

Effects of the addition of starches with different amylose contents on kimchi microbiota and metabolites

Starch paste, one of the ingredients used in kimchi, facilitates fermentation by acting as a nutrient source for microorganisms during the fermentation process. Changes in microbial communities and metabolites were investigated to understand the effects of starch with varying amylose contents on kimchi fermentation. Although adding starch paste changed the microbial profile of kimchi, there was no significant difference in the amylose content. In the starch paste-added kimchi, Leuconostoc, which is mainly involved in kimchi fermentation, was found to be relatively more abundant than in kimchi without starch. Furthermore, sugars such as glucose and mannitol had increased, but citric acid and tryptophan had decreased in the starch paste-supplemented kimchi. This indicates that adding starch paste can directly contribute to the taste of kimchi. Leuconostoc showed a negative correlation with many metabolites, except spermidine, suggesting that metabolite consumption was driven by Leuconostoc. Except for tryptophan metabolism, most of the metabolisms affected by the addition of starch were related to sugar metabolism. This study provides basic information for understanding the effect of starch, an essential ingredient in kimchi manufacturing, on the microorganisms and metabolites in kimchi.

Understanding the multi-scale structure and physicochemical properties of millet starch with varied amylose content

The multi-scale structure and physicochemical properties of starch from five indigenous millet varieties were investigated and their correlations were revealed. Results showed that apparent amylose content (AAC) ranged from 12.3% to 27.4%, and as the amylose increasing, the ordered degree of starch double-helical, ordered molecular structure and crystalline structures displayed a declined trend. All millet starches showed polygonal, spherical or irregular shapes varied with size, but XIN-3 starch granules (highest AAC) presented higher granule rigidity, compactness and bulk intensity. Specifically, the ordered molecular structure (e.g., higher double-helix content, short-range ordered degree and relative crystallinity) of millet starch with low amylose limited the swelling degree of starch granules and in turn decreased the characteristic viscosity. However, rapidly digestible starch (RDS) was significantly negatively correlated with AAC and ordered molecular structure. The information obtained in this study would be significant in the rational utilization of these millet starches in food industry fields.

Type‐2 Diabetes and Identification of Major Genetic Determinants of Glycemic Index in Rice – A Review

AbstractRice consumers of different parts of the world always face the risk of diabetes and related health complications. Dietary intervention is the best adapted measure to maintain blood glucose levels and manage the diseases in rice consuming populations. The glycemic index of rice varieties is negatively correlated to the amylose content. Research studies have proven that the consumption of rice varieties with low glycemic index has beneficial effects in controlling diabetes. The genetic basis for the diversity observed for amylose content in different rice varieties is well elucidated. Waxy gene (Wx) is known to encode Granule–Bound Starch Synthase I (GBSS I) enzyme, which determines the amylose content in rice. Different allelic variations of Wx gene exist, which can be correlated to varying amylose content in rice. The PCR‐based markers for detecting single nucleotide polymorphism mutation at Wx locus provides a cost‐effective alternative to genotype rice varieties. This review outlines the anti‐diabetic properties of rice and strategies to identify rice varieties with a low glycemic index at the molecular level. The molecular basis of the glycemic index allows breeders to successfully identify rice germplasms with low glycemic index and engineer rice varieties with high grain yield and low glycemic index.

Investigation of structural and physico-chemical properties of rice starch with varied amylose content: A combined microscopy, spectroscopy, and thermal study

Starch from a given botanical source can vary considerably in terms of physicochemical properties in its native and hydrolyzed forms. The current study investigated the structural and functional characteristics of starch from ten indigenous rice varieties endemic to Northeast India. In vitro enzymatic hydrolysis was used to reveal the dextrose equivalent profile of each type of starch. Gezep Sali and Betguti Sali respectively exhibited the highest and lowest starch hydrolysis. Among the ten rice varieties, amylose content varied between 7.50 and 28.58%. Optical and scanning electron microscopy (SEM) revealed the polyhedral shape of the native starch granules and deformation of the shape upon enzymatic hydrolysis. Second harmonic generation (SHG) microscopy and X-ray diffraction (XRD) analysis confirmed the presence of and variations in starch crystallinity. XRD revealed spectral peaks characteristic of A-type starch crystals in the native form. The elevated intensity of XRD peaks in hydrolyzed starch granules confirmed the occurrence of amylose hydrolysis rather than hydrolysis in amylopectin regions. Fourier transform infrared (FTIR) spectra revealed the common stretching and bending of bonds in all native starches; however, changes were observed in the fingerprint region (1080, 1000, 926 cm−1) of hydrolyzed starch granules, which indicates the amylolysis of the amylose region and disturbances in the ordered arrangement in the crystalline part. Differential scanning calorimeter (DSC) endotherms revealed the highest and lowest gelatinization peak temperatures in Harfoni (78 °C) and Tulosi Sali (41 °C) rice cultivars, respectively. The findings in this study can help to optimize the usage of rice starch in food and non-food industries. Furthermore, understanding the control points of starch digestion and genetically tailoring rice grains with different digestibility could be beneficial for nutraceutical applications.

Varying amylose contents affect the structural and physicochemical characteristics of starch in mung bean

ABSTRACT Mung bean starches are widely used for producing transparent, good-quality noodles in the food industry. This study isolated starches from eight mung bean varieties and investigated how the amylose contents (19.1–32.9%) of the beans affected the structures, physicochemical properties, and resistant starch (RS) fractions of these starches. The starches were classified into three groups according to their amylose content: low-amylose starches with <25% amylose content (TN182, DXVN7, and DX208 varieties), intermediate-amylose starches with 25%-30% amylose contents (DX14, KPS1, and V123 varieties), and high-amylose starches with >30% amylose contents (T135 and DX044 varieties). The amylose content of mung bean starches negatively correlated with the average degree of polymerization () of the starch, whereas the mung bean variety dictated the average chain length (, degree of order, and short-range molecular order of the starch. All mung bean starches were found to have an A-type crystalline structure with a relative crystallinity of 25.8–34.7%. The starches with higher amylose contents exhibited higher peaks, final viscosities, and setbacks than the other starches. The contents of the RS fraction were in the range of 3.6–13.0%; the starches of the DX14, T135, and DX044 varieties had higher contents of the RS fractions (9.0%, 9.9%, and 13.0%, respectively) than the starches from the other mung bean varieties. Abbreviations: MB1, starch isolated from TN182 variety; MB2, starch isolated from DXVN7 variety; MB3, starch isolated from DX208 variety; MB4, starch isolated from DX14 variety; MB5, starch isolated from KPS1 variety; MB6, starch isolated from V123 variety; MB7, starch isolated from T135 variety; MB8, starch isolated from DX044 variety.

Influence of an O/W emulsion on the gelatinization, retrogradation and digestibility of rice starch with varying amylose contents

The present study aimed to explore the effects of oil-in-water emulsion on the gelatinization, retrogradation, and digestibility of indica rice starch (IRS), japonica rice starch (JRS), and glutinous rice starch (GRS). With the emulsion, the three types of starch granules exhibited limited swelling and increased gelatinization enthalpy during heating, and changed the peak viscosity and final storage modulus of starch gelatinization. After being refrigerated at 4 °C, the emulsion changed the firmness of starch gel, reduced the water migration, and increased the water-holding capacity of the three starch gels. X-ray diffraction and scanning electron microscopy revealed that the emulsion could delay the retrogradation of the three types of starches, and the inhibitory effect was related to the content of amylose. The results of in vitro digestion showed that the emulsion significantly increased the slowly digestible starch and resistant starch contents in the three types of starch. These findings indicated that the emulsion could inhibit the gelatinization and retrogradation properties, as well as delay the digestion of different types of starch, providing a theoretical basis for expanding the application of the emulsion in starch foods.

Interactions between caffeic acid and corn starch with varying amylose content and their effects on starch digestion

This study aimed to evaluate the physical-chemical interaction between caffeic acid (CA) and gelatinized corn starch with varying amylose and its potential effect on starch digestion. Iodine binding reaction indicated that the absorbance of starch-iodine complex was lower than that in the starch-CA sample. Furthermore, the decrease of absorbance in high amylose corn starch was the most obvious. The affinity constant for CA obtained by isothermal titration calorimetry analysis increased with the amylose content. In the 1H NMR analysis, the peaks of starch hydroxyl groups at 5.4 and 5.5 ppm became broader after the addition of CA, demonstrating that CA interacted with the selected starches via the hydroxyl groups to form hydrogen bonds. In vitro digestibility studies revealed that the interaction between CA and starch had different effects on starch with different amylose content. Moreover, it was revealed that 2% of CA promoted the hydrolytic process, but a drastic reduction of the hydrolytic process occurred upon increasing the CA to 10% for CS. These results suggested that amylose content and certain interactions with CA was a potential reason affecting the mode of interaction, thus altering the digestion.

PSVI-32 The effects of varying amylose levels in different diets on digestibility and glycemic response in canines

Abstract This study was conducted to compare the digestibility of pulse-based diets to grain-based diets based on varying levels of amylose and study how changes in digestibility impacts glycemic response in dogs. To establish glycemic response, six diets were formulated at an inclusion level of 20% available starch with varying amylose content. A grain-based diet was formulated using rice, while pulse-based diets consisted of smooth pea, wrinkled pea (4140–4 and Amigold varieties), faba bean, or lentil. Beagles (n = 8, 4 females, 4 males) were fed the 6 different test diets for 7 days in a randomized, cross-over, blinded design. At the end of each feeding period, fecal samples were collected and beagles were fasted overnight and subjected to a glycemic test (1g/kg of diet or glucose fed). Data collected were statistically analyzed using SigmaPlot 12.0 and significance was declared at P ≤ 0.05. Amylose levels of diets varied from 4.64% to 14.82% on a dry basis. The rice-based diet had the lowest amylose content, while the wrinkled pea (Amigold variety) diet had the highest amylose content. Following the collection of glycemic response and fecal data, repeated-measures, 1-way ANOVA’s were conducted. There were significant differences observed between diets based on peak glucose levels (mmol/L, P = 0.01). The rice diet had the highest peak in glucose, while the lentil-based diet had the lowest glucose peak. Significant differences were also seen between diets based on their digestibility (P &amp;lt; 0.001). Rice, lentil, faba bean and smooth pea-based diets had the highest levels of digestibility, while wrinkled pea varieties had decreased digestibility. Furthermore, varying amylose found in diets can be viewed as an impacting factor on glycemic response and digestibility. Incorporating pulses with higher amounts of amylose could be utilized in dog diets to promote a low glycemic response through decreased rates of digestibility.

Physicochemical properties and in vitro digestibility of mung-bean starches varying amylose contents under citric acid and hydrothermal treatments

In this study, starches of three mung bean cultivars (Vigna radiata) having different amylose contents were isolated and modified using a combination of citric acid and heat-moisture treatment (CA-HMT) or a combination of citric acid and annealing treatment (CA-ANN). Physicochemical properties and in vitro digestibility of native and treated mung bean starches were investigated. Resistant starch (RS) contents of the high-amylose, medium-amylose and low-amylose starches treated with CA-ANN were 41.1%, 35.7% and 27.1%, respectively, being higher than those treated with CA-HMT or native starches in the same variety. The CA-ANN did not affect the morphology and crystallinity of the starches. However, the starches treated by the CA-HMT were partly gelatinized and had higher degree of relative crystallinity as compared to the native starches. The DP¯s, swelling power, and viscosity of the treated starches were significantly lower than those of the native starches. The high-amylose mung bean starch was greatly affected by the treatments rather than medium- or low-amylose mung bean starch.

Effect of parboiling methods on the physicochemical characteristics and glycemic index of rice varieties

The effect of open steaming (HS) and pressure (PP) parboiling on the physicochemical characteristics and glycemic index (GI) of five different Indian rice varieties with varying amylose contents was investigated. Results showed that the severity of processing had a significant effect on the physicochemical properties of rice. PP resulted in reduced whiteness (18.83 ± 0.66 to 26.03 ± 1.27%), increased transparency (1.64 ± 0.05 to 2.05 ± 0.08%), hardness (6.66 ± 0.63 to 7.82 ± 1.19 kg) and equilibrium moisture content (117.59 ± 11.37 to 183.69 ± 39.46%db). PP rice also showed higher cooking time (40.28 ± 0.35 to 59.31 ± 0.69 min), water absorption ratio (4.52 ± 0.06 to 5.23 ± 0.04), and sedimentation volume than HS and non-parboiled counterparts. An increase in parboiling temperature significantly affected the pasting profiles of rice flour. Among the treated samples, the degree of gelatinization was higher for PP rice (70.80 ± 6.83 – 85.24 ± 1.48%). Alkali spreading value explained the lower gelatinization temperature for parboiled rice as compared with the non-parboiled counterpart. Higher amylose content of rice was associated with lower GI values and parboiled rice had a significantly lesser GI. The findings of this study provide insights on rice parboiling methods, particularly for the diabetic population.

Fecal microbiota responses to rice RS3 are specific to amylose molecular structure

Resistant starch type 3 (RS3) benefits colon health, but the molecular structural reasons for this effect are unclear. Five rice starches with varied amylose content (19.1 %–40.6 %) were used to investigate their effect on gut microbiota. Size-exclusion chromatography and fluorophore-assisted carbohydrate electrophoresis were used to characterize whole starch molecular size distributions and chain length distributions. It was found that RS3 with more chains of degree of polymerization (DP) 36–100 and smaller molecular size can promote the relative abundance of some classes of gut bacteria, while other classes were promoted by RS3 with fewer chains of DP 36–100 and larger molecular size. X-ray diffraction and scanning electron microscopy showed that crystallinity types B or C and differences in physical surface affected the microbiota. This study shows that RS3s with different fine structures are utilized differently by gut microbiota, which may be applied to develop functional foods for gut health.