Rate Of Starch Hydrolysis Research Articles

Effect of different processes on composition, properties and in vitro starch digestibility of grass pea flour

The objective of this study was to determine the effect of processes of seed disintegration and cooking and their order on digestibility of starch of grass pea seeds. Analyses were carried out in flour made of cooked grass pea seeds (CSF) and in flour made of raw ground seeds and subjected to identical treatments (CF). In addition, physicochemical properties of flour were determined to identify factors which affected starch digestibility. In CSF, analyses demonstrated decreased temperatures and enthalpy of transition and an increased range of transition temperatures. However, enthalpy value was still relatively high, probably as a result of starch retrogradation during drying. Compared to CF, the rate of starch hydrolysis in CSF was significantly lower and, as a consequence, the predicted glycemic index (pGI) was also significantly lower. The rate of CF starch hydrolysis and a high value of its pGI point to a highly significant effect of seeds disintegration before cooking, which resulted in complete gelatinization of starch during cooking. In contrast, incomplete gelatinization of starch during cooking and retrogradation of gelatinized starch during drying were observed in CSF. These changes caused slower starch hydrolysis, lower pGI, and significantly higher content of resistant starch in these flours compared to CF. Results obtained in study demonstrate that flour from cooked grass pea seeds may be used in food products to decrease their GI and to enrich them in resistant starch.

α-Amylase@Ferria: Magnetic Nanocomposites with Enhanced Thermal Stability for Starch Hydrolysis.

The present study is devoted to the development of a new class recyclable magnetic catalytic nanocomposites for starch hydrolysis. α-Amylase was entrapped within a magnetite-derived xerogel matrix in a course of a room-temperature sol-gel transition, leading to enzyme immobilization within the pores of a rigid magnetic matrix. For hybrid organo-inorganic composites with enzyme mass fractions less than 10 wt %, no enzyme leaching was observed. At 80 °C, the amylase@ferria composite demonstrates catalytic activity on the level of 10 units/mg and the starch hydrolysis rate comparable to free enzyme, while at 90 °C, the activity of amylase@ferria is at least twice higher than that of free amylase as a result of higher thermal stability of the composite. Entrapped amylase showed excellent stability and lost only 9% of its activity after 21 days of storage in a buffer solution, while free enzyme was totally inactivated after 17 days. The material can be used as either a magnetically separable reusable catalyst or a catalytic ceramic coating with at least 10 cycles of use.

The relationship between enzyme hydrolysis and the components of rice starches with the same genetic background and amylopectin structure but different amylose contents

The relationship between starch components and hydrolysis previously focused on starches with different amylose contents (ACs) and amylopectin structures. In this study, starches were isolated from six rice seeds with the same genetic background but different activities of granule-bound starch synthase I. The starch components and enzyme hydrolysis were measured and analysed to reveal their relationships. The results showed that the six rice starches had the same amylopectin structure but different ACs ranging from approximately 1%–15%. The starch component parameters measured by different methods were significantly correlated with each other. The hydrolysis parameters of starch by both α-amylase and amyloglucosidase were analysed using three methods including a non-linear fit to the degree of hydrolysis, a first-order kinetics fit to the degree of hydrolysis, and a first-order kinetics fit to the hydrolysis rate, and they had significant correlation each other. Waxy starch had a fast hydrolysis rate and showed a single hydrolysis phase during early hydrolysis, while starch with a high AC had a bi-phasic hydrolysis process. Starch component parameters including the maximum absorption wavelength, iodine blue, AC, and low molecular weight fraction were significantly negatively correlated to the hydrolysis rate of starch. The above results indicated that starches with different ratios of amylose to amylopectin but the same amylopectin structure had significantly different hydrolysis properties. This study could provide some information for rice quality breeding and starch applications through changing the activity of granule-bound starch synthase I.

Modification of the digestibility of extruded rice starch by enzyme treatment (β-amylolysis): An in vitro study

The rate and extent of starch hydrolysis in the digestive tract impacts blood glucose levels, which may influence an individual's susceptibility to diabetes and obesity. Strategies for decreasing starch digestibility are therefore useful for developing healthier foods. β-amylase is an exo-hydrolase that specifically cleaves α-1,4 glycosidic linkages of gelatinized starches. In this study, starch granules were disrupted by extrusion under different feed moisture conditions, and then subjected to β-amylolysis. The degree of starch gelatinization increased with increasing feed moisture content during extrusion, leading to faster β-amylolysis. The hydrolysis of in vitro starch digestion study was reduced for extruded samples treated with β-amylase, which was attributed to an increase in resistant starch (RS) after β-amylase treatment. Indeed, X-ray diffraction (XRD) indicated that the crystalline structure in the extruded starch was either partially or fully lost after β-amylase treatment. Similarly, Fourier transform infrared (FTIR) analysis indicated there was a higher level of amorphous regions in the starch after β-amylase treatment. Overall, our results suggest that enzymatic treatment of extruded starch with β-amylolysis reduces the ratio of crystalline-to-amorphous regions, which increases the level of resistant starch, thereby slowing down digestion. These results have important implications for the development of healthier starch-based foods.

Modulation of Carbohydrate Digestibility of North Indian Parotta Using Protein and Dietary Fiber Based Functional Ingredients

Diet is the cornerstone in the management of hyperglycemia. Indian diets are predominantly cereal based providing a higher proportion of carbohydrate. Hence whole wheat flour (staple cereal) is substituted with a blend of 20–30% of chickpea flour, psyllium husk, fenugreek seed powder (CPF) for increasing the protein and dietary fiber contents. The effects of CPF on the rheological characteristics of whole wheat flour; physico‐chemical, sensory characteristics, and carbohydrate digestive profile of north Indian parotta (NIP) are studied. The results show an increase in the farinograph water absorption; extensograph resistance to extension; amylograph pasting temperature, peak viscosity, and a decrease in the extensograph extensibility. The overall quality score of NIP increases from 50 to 54, from a maximum score of 60 with an addition of 25% CPF of and decreased to 40 for 30% CPF content. Hence NIP with 25% CPF is selected for determinations of protein, dietary fiber, carbohydrate digestibility, kinetics of starch digestion in comparison with control NIP. The NIP with 25% CPF shows higher protein, dietary fiber, slowly available glucose, resistant starch, and lower rapidly available glucose than the control NIP. The differences in the digestibility profile are found to be statistically significant. The rate of starch hydrolysis and kinetics further confirmed the reduced glucose release of the NIP with 25% CPF. The predicted glycemic index of the NIP with 25% CPF is found to be “low.”

Combi-metal organic framework (Combi-MOF) of α-amylase and glucoamylase for one pot starch hydrolysis

The multi-enzyme biocatalyst allows to run in vitro multi-step cascade reactions in single pot. An efficient combi-metal organic frameworks (combi-MOF) of α-amylase and glucoamylase for one pot starch hydrolysis was constructed by mixing zinc acetate and 2‑methylimmidazole with enzyme mixture in one pot under biocompatible conditions. The prepared combi-MOF was characterized and analyzed by powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Thermo-stability was evaluated for combi-MOF in the range of 55 to 75°C which showed three folds improved stability in terms of half-life. In kinetic parameter studies, rate of starch hydrolysis (Vmax) of combi-MOF was found to be enhanced after co-immobilization. Further, combi-MOF was recycled in batch mode which retained up to 52% residual activity after five successive cycles of reuse. In addition to that, combi-MOF exhibited extraordinary storage stability till 24days. At the end, starch hydrolytic activity of combi-MOF was tested for different sources of starch (corn, rice, wheat and potato) which exhibited higher rate of hydrolysis than mixture of free enzymes due to spatially co-localized multi-enzymatic systems.

Impact of Heat Moisture Treatment and Hydration Level of Flours on the Functional and Nutritional Value-Added Wheat-Barley Blended Breads

The impact of heat moisture treatment (HMT) of flours on the techno-functional and nutritional patterns of binary flour bread matrices (wheat/barley, WT/CB, 60:40, w/w) was investigated in untreated (−) and HMT (+) samples made at 160 and 170 dough yield (DY) levels. Assessment was performed by determining viscoelastic (stress relaxation test) and mechanical (double compression test) behaviours, volume (seed displacement), colour (Photoshop system), crumb grain (digital image analysis), starch digestibility (enzyme hydrolysis) and staling kinetics (Avrami equation), bioaccessible polyphenol content (digestive enzymatic mild extraction) and anti-radical activity (DPPH●). A superior functional profile was provided by HMT of CB flour in the blend WT−CB+ when hydrated at DY 170 compared to the untreated control WT−CB−. The sample exhibited a similar specific volume, more cohesive, springier, more resilient crumb, with similar rate and extent of crumb firming on ageing, and similar colour pattern but finer and more uniformly sized cell structure, and deserved similar sensory ratings as the control WT−CB− concerning cell uniformity, smoothness and typical smell and taste. Digestible starch kinetic curves of blended breads pointed out samples WT−CB+ and WT+CB+ as matrices expliciting a lower degree and slower rate of starch hydrolysis when mixed at low and high DY, respectively. A similar anti-radical activity for composite bread matrices was evidenced regardless of either HMT or DY.

Winter-hardiness assessment in groundcovering roses by histochemistry

The paper presents the results of the seasonal dynamics of starch and lipids study in annual shoots of rose species and cultivars growing in the urbanized medium of a Siberian megapolis under continental climate conditions. The prospects of prediction the winter hardiness of roses by the rate of starch hydrolysis and lipids storage in pre-winter period are shown. During this period, starch is observed in medullary rays, perimedullary region and pith (centripetal tendency), while primary cortex, phloem and cambium are rich in lipids (centrifugal tendency).

Effects of explosion puffing on the nutritional composition and digestibility of grains

ABSTRACTThe objective of this study was to investigate the effects of explosion puffing on the nutritional composition, physical properties, and digestibility of grains including millet, barley, black rice, rice, glutinous rice, and wheat. Explosion puffing of grains resulted in the nutritional composition with higher total sugar content and lower moisture, starch and fat contents. Although the protein content scarcely changed comparing with the untreated grains, the solubility declined significantly. Moreover, explosion puffing could significantly improve the physical properties including the water absorption index, water solubility index and gelatinization degree. The in vitro digestion experiment was employed to investigate the influences of explosion puffing on the starch hydrolysis rate and free amino acid content, and it was indicated that the digestibility of the starch and protein in grains was highly improved. The results demonstrated that explosion puffing is a suitable technique to improve the physical properties and digestibility of grains, which provided the theoretic foundation for the use of explosion puffing technology in coarse cereal processing.

In vitro examination of starch digestibility and changes in antioxidant activities of selected cooked pigmented rice

Abstract The impact of morphological characteristics of three different cultivars (red, black, and purple) of cooked pigmented Thai rice on changes in starch hydrolysis and antioxidant potential during simulated in vitro digestion was examined. Comparison with the respective homogenized cooked rice slurries, which were regarded as structure-less samples, demonstrated that the intact cooked grain samples tended to show a reduced rate of starch hydrolysis and fewer bioactive compounds during simulated digestion. However, the change of the ferric reducing antioxidant power (FRAP) value for the Kum Luempua (purple waxy) variety cooked by steaming showed a different trend between the intact grain and homogenized slurry, although the changes in 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging activity for the intact grain were mostly similar to those of its slurry. The results of this study indicated that the morphological grain attributes of cooked pigmented rice were related to not only starch digestibility, which was associated with changes in the glucose index value, but also with changes in antioxidant activity in the mucosal layer of the gut tract.

Low frequency ultrasonic-assisted hydrolysis of starch in the presence of α-amylase

Hydrolysis of starch is an important process in the food industry and in the production of bioethanol or smaller carbohydrate molecules that can be used as starting blocks for chemical synthesis. Such hydrolysis can be enhanced by lowering the pH, heating the reaction mixture or catalyzing the reaction with enzymes. This study reports the effect of sonication on the reaction rate of starch hydrolysis at different temperatures, in the presence or absence of alpha-amylase. Starch Azure, a commercially available potato starch covalently linked with Remazol Brilliant Blue, has been chosen since its hydrolysis releases a blue dye, which concentration can be monitored by UV Vis spectroscopy. Ultrasounds, regardless of experimental conditions, provide the highest reaction rate for such hydrolysis.

Effects of palm oil on structural and in vitro digestion properties of cooked rice starches

The glycemic potency of rice depends upon the rate and extent of starch hydrolysis by pancreatic amylase and intestinal alpha-glucosidases. However, complexation of starch molecules with lipids is known to reduce the enzymic hydrolysis. In this study, we elucidated the varietal effect of rice starches on the formation of amylose-lipid complex, after cooking with palm oil, a common cooking oil. The amount of complexed lipid followed the order of black (2.5%), brown (2.5%), white (1.5%) and waxy (0.5%) rice starches. After heating with palm oil, the relative crystallinity of all the rice starches were destroyed whilst a V-type peak at 20° 2θ was increased, indicating the formation of amylose-lipid complex. This is also suggested from the DSC data where the melting enthalpy increased significantly after cooking in palm oil for all rice samples. The formation of amylose-lipid complex reduced the in vitro starch digestibility, enhancing the resistance starch content whilst decreasing the rapid and slow digestion fractions of non-waxy varieties. The rate and extent of in vitro starch hydrolysis seems to be dependent on the presence or absence of amylose fraction. With the mechanistic details, the present study suggests the applicability of palm oil addition during the rice cooking to enhance its nutritional functionality.

Use of fermented milling by-products as functional ingredient to develop a low-glycaemic index bread

Selected Lactobacillus plantarum DSM 32248 and Lactobacillus rossiae DSM 32249, isolated and identified from wheat germ, were used to ferment a milling by-products mixture. Lactic acid bacteria metabolisms improved the functional properties of wheat bran and germ, which are considered important sources of functional compounds. Wheat breads were manufactured using 15% (w/w) of fermented (and unfermented) milling by-products, and compared to baker’s yeast wheat bread manufactured without the addition of milling by-products. The use of the fermented ingredient improved the biochemical, functional, nutritional, textural, and sensory features of wheat bread, showing better performances compared to the solely use of wheat flour. Protein digestibility, nutritional indexes, and the rate of starch hydrolysis markedly improved using fermented milling by-products as ingredient. Enriched bread was also characterized by high content of dietary fibre and low glycaemic index determined in vivo.This study exploited the potential of fermented milling by products as functional ingredient. According to the Regulations the bread made under this study conditions can be defined as “high fibre content” and “low glycaemic index”. A number of advantages encouraged the manufacture of novel and healthy and functional leavened baked goods.

Comparative Study of Starch Characteristics, In-Vitro Starch Digestibility and Glycemic Index of Some Starchy Foods Consumed in Nigeria

<p><em>The study investigated the carbohydrate characteristics and in-vitro starch digestibility of some starchy food consumed in Nigeria. Ten foods samples (cassava, yam, red and white sorghum, rice, plantain, banana, semovita, noodles and bread) were selected. The content of starch, amylose and sugar were determined by colorimetric method, in vitro rate of starch hydrolysis was evaluated by multi-enzyme digestion method over a period of two hours, the glucose released was estimated by colorimetric method and was compared to the reference food (bread). The result showed that the percentage moisture content and total starch ranged from 9.8 to 15.3% and 236 to 248 mg/g, while amylose, Rapidly Digestible Starch (RDS) and Resistance Starch (RS) ranged from 8.41 to 19.2%, 30.8 to 51% and 7.8 to 37.4%, respectively. The in-vitro digestibility study indicated that the equilibrium Concentration (C?), Kinetic constant (K ), Hydrolysis Index (HI) and Glycemic Index (GI) ranged from 34 to 64.9, and 0.02 to 0.07, 56.6 to 104 and 71 to 96.8, respectively. Positive correlations (P < 0.05) exist between RDS and GI (r = 0.700) and RS and amylose (r = 0.899) The study revealed that, structure of dietary carbohydrate could greatly influenced the Glycemic Index, plantain and noodles with low RDS and low hydrolysis constant may be beneficial in management of diabetes whereas sorghum, semovita, cassava and bread with high RDS, and high GI should be taken sparingly or combined with high protein and low glycemic load foods.</em></p>

The UV aging properties of maleic anhydride esterified starch/polylactic acid composites

Esterified starch/polylactic acid (ES/PLA) blending composite was prepared by melting extrusion with maleic anhydride esterified starch and PLA as the raw materials. The composite was accelerated aging by using UV aging box, and its properties were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and mechanical testing machine. FT-IR and SEM results show that the infrared absorption peak intensities of C-O, C-H, and C=O in aged samples decrease gradually with increasing aging time. The damage degree of surface and internal of aged samples increases gradually. XRD analysis results show that after aging treatment, the crystalline diffraction peak of thermoplastic esterified starch at 2θ = 21° disappears and the diffraction peaks of PLA at 2θ = 16.5° appear, indicating that the hydrolysis rate of esterified starch is greater than that of PLA. The crystallinity of PLA in aged sample shows an increasing trend at first followed by a decreasing one along with the increasing time of aging treatment, suggesting that the hydrolysis of amorphous regions of PLA is more preferential than its crystalline regions. Because of the influence of crystal structure and the change of composition structure, the initial decomposition temperature of aging test specimen gradually increases with the extension of aging time. The maximum decomposition rate temperature and residual mass increases at first, and then decrease after the aging time extending to 1 600 h. As the aging time increases, the damage degree of combination interface between esterification starch and PLA is exacerbated, resulting in the tensile strength and bending strength of aged specimen decreasing gradually.

Characterization of acid hydrolysis of granular potato starch under induced electric field

Compared to traditional heating methods by static immersion or stirring, induced electric field (IEF) treatment can significantly increase hydrolysis rate of potato starch. The aim of this study was to examine the characterization of acid hydrolysis of granular potato starch under IEF. Potato starch was hydrolyzed using 0.15 mol/L HCl combined with IEF (IEF-HCl) at an excitation voltage of 75 V from 4 h to 120 h. The changes in granular, crystal, and molecular structure of starch granules during IEF-HCl hydrolysis were investigated. Scanning electron microscope analysis showed the outer surface of potato starch was firstly attacked by free ions and then the inner structures was completely disrupted and broken into pieces. X-ray diffraction studies indicated that the crystallinity decreased from 38.92% to 34.9% after 4-h hydrolysis, and then gradually increased to 41.88% as hydrolysis time increased to 96 h, but decreased thereafter. The weight-average molecular weight dramatically decreased from 104.7 × 106 Da to 9.291 × 106 Da in the first 24 h and then decreased gradually. These results suggested that there were three steps in the catalytic process of IEF-HCl hydrolysis. Initially, hydrogen ions destroyed the external crystalline shell of granules. Next, hydrogen ions attacked the loose amorphous region and dense crystalline part within starch granules simultaneously. Finally, the remaining crystalline region was hydrolyzed slowly.

Incorporation of dietary fibre-rich oyster mushroom (Pleurotus sajor-caju) powder improves postprandial glycaemic response by interfering with starch granule structure and starch digestibility of biscuit.

The purpose of this study was to determine the effects of Pleurotus sajor-caju (PSC) powder addition at 0, 4, 8 and 12% levels on the nutritional values, pasting properties, thermal characteristics, microstructure, in vitro starch digestibility, in vivo glycaemic index (GI) and sensorial properties of biscuits. Elevated incorporation levels of PSC powder increased the dietary fibre (DF) content and reduced the pasting viscosities and starch gelatinisation enthalpy value of biscuits. The addition of DF-rich PSC powder also interfered with the integrity of the starch granules by reducing the sizes and inducing the uneven spherical shapes of the starch granules, which, in turn, resulted in reduced starch susceptibility to digestive enzymes. The restriction starch hydrolysis rate markedly reduced the GI of biscuits. The incorporation of 8% PSC powder in biscuits (GI=49) could be an effective way of developing a nutritious and low-GI biscuit without jeopardizing its desirable sensorial properties.

Influence of fermented faba bean flour on the nutritional, technological and sensory quality of fortified pasta.

Faba bean has gained increasing attention from the food industry and the consumers mainly due to the quality of its protein fraction. Fermentation has been recently recognized as the most efficient tool for improving its nutritional and organoleptic properties. In this study, faba bean flour fermented with Lactobacillus plantarum DPPMAB24W was used to fortify semolina pasta. Pasta samples including different percentages of fermented faba bean flour were produced at the pilot-plant level and characterized using an integrated approach for chemical, nutritional, technological, and sensory features. At a substitution level of 30%, pasta had a more homogeneous texture and lower cooking loss compared to 50% addition. The impact of faba bean flour addition on pasta technological functionality, particularly of the protein fraction, was also assessed by scanning electron microscopy and textural profile analysis. Compared to traditional (semolina) pasta and pasta containing unfermented faba bean flour, the nutritional profile (in vitro protein digestibility and nutritional indexes - chemical score (CS), sequence of limiting essential amino acids, Essential Amino Acid Index (EAAI), Biological Value (BV), Protein Efficiency Ratio (PER), and Nutritional Index (NI)) and the resistant starch content of pasta containing 30% fermented faba bean flour markedly improved, while the starch hydrolysis rate decreased, without negatively affecting technological and sensory features. The use of fermentation technology appears to be a promising tool to enhance the quality of pasta and to promote the use of faba bean flour.

Effect of the glass transition temperature on alpha-amylase activity in a starch matrix

This study optimises a protocol for the estimation of α-amylase activity in a condensed starch matrix in the vicinity of the glass transition region. Enzymatic activity on the vitrified starch system was compared with that of a reference substrate, maltodextrin. The activity was assayed as the rate of release of reducing sugar using a dinitrosalicylic acid procedure. The condensed carbohydrate matrices served the dual purpose of acting as a substrate as well as producing a pronounced effect on the ability to enzymatic hydrolysis. Activation energies were estimated throughout the glass transition region of condensed carbohydrate preparations based on the concept of the spectroscopic shift factor. Results were used to demonstrate a considerable moderation by the mechanical glass transition temperature, beyond the expected linear effect of the temperature dependence, on the reaction rate of starch hydrolysis by α-amylase in comparison with the low-molecular weight chain of maltodextrin.

Effects of extrusion cooking and wheat bran substitution on the functional, nutritional, and rheological properties of cassava‐defatted toasted soy composite

Wheat bran was substituted with cassava‐defatted toasted soy composite at 0, 10, and 20% substitution levels followed by extrusion cooking and some nutritional, functional, and rheological properties of the extrudates were determined. There was a significant (p < 0.05) increase in starch digestibility of composites after extrusion cooking, but the substitution of wheat bran lowered the rate and extent of starch hydrolysis. Extrusion cooking led to a reduction in NSI and IVPD. Substitution of cassava‐defatted toasted soy composite with wheat bran reduced expansion and solubility index of extrudates. Extrusion cooking also promoted fiber fragmentation with a consequent increase in soluble dietary fiber and a decrease in insoluble dietary fiber content. All the composites exhibited a shear thinning behavior and the composite with 20% wheat bran had the highest viscosity. The result indicates that substitution of starch with wheat bran together with extrusion cooking can be applied to produce products with improved nutritional and functional properties.