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Physical properties of starch granules and susceptibility to enzymatic degradation
Abstract
Starch, the most abundant component of the diet, is characterized by its variety as well as the versatility of its derivatives in foods. This paper is an overview of the main physical characteristics of the native starch granule. Three different levels of organization are presented: macromolecular structure, crystalline organization and ultrastructure. Starch consists of amylose and amylopectin. Amylose is an essentially linear polymer composed of alpha-1,4-linked D-anhydroglucose units (AGU); amylopectin is a branched polymer clustering a large amount of short linear chains by the linkage of alpha-1,6-bonds, constituting about 5% of the total glycosidic bonds. In the native starch granules, a large number of the macromolecular chains are organized in crystalline structures. Three forms have been found, the A, B and C patterns. So far only A and B starch crystals have been modelled. There is a variation in the susceptibility of the starch granules to enzymatic digestion. This is explained by variation in the morphology of the granules and their crystalline organization.
... To take this into account, we could randomly pick the dihedral angles of the α − 1, 4 bonds using the Ramachandran plots of their energetically favourable regions. As a first trial, we could use that of maltose, that is well characterised [56]. We expect that, by introducing such disorder in the angles, chains will appear longer. ...
In humans, glycogen storage diseases result from metabolic inborn errors, and can lead to severe phenotypes and lethal conditions. Besides these rare diseases, glycogen is also associated to widely spread societal burdens such as diabetes. Glycogen is a branched glucose polymer synthesised and degraded by a complex set of enzymes. Over the past 50 years, the structure of glycogen has been intensively investigated. Yet, the interplay between the detailed three-dimensional glycogen structure and the related enzyme activity is only partially characterised and still to be fully understood. In this article, we develop a stochastic coarse-grained and spatially resolved model of branched polymer biosynthesis following a Gillespie algorithm. Our study largely focusses on the role of the branching enzyme, and first investigates the properties of the model with generic parameter values, before comparing it to in vivo experimental data in mice. It arises that the ratio of glycogen synthase over branching enzyme reaction rates drastically impacts the structure of the granule. We deeply investigate the mechanism of branching and parametrise it using distinct lengths. Not only do we consider various possible sets of values for these lengths, but also distinct rules to apply them. We show how combining various values for these lengths finely tunes glycogen macromolecular structure. Comparing the model with experimental data confirms that we can accurately reproduce glycogen chain length distributions in wild type mice. Additional granule properties obtained for this fit are also in good agreement with typically reported values in the experimental literature. Nonetheless, we find that the mechanism of branching must be more flexible than usually reported. Overall, our model provides a theoretical basis to quantify the effect that single enzymatic parameters, in particular of the branching enzyme, have on the chain length distribution. Our generic model and methods can be applied to any glycogen data set, and could in particular contribute to characterise the mechanisms responsible for glycogen storage disorders.
... Legumes produce relatively low glycemic responses in both healthy individuals and in diabetics [30,31]. The components present in legumes, particularly the soluble dietary fibre [32], and the nature of the starch [33] can influence the rate by which glucose is released from starch and consequently absorbed from the small intestine. This makes it suitable for use in controlling postprandial rise of blood glucose levels. ...
Some legumes are commonly used as commercial food crops in West Africa while others are lesser known, neglected or underutilized. This research work is aimed at the evaluation of the chemical compositions and possible utilization of the legume Lablab purpureus and Phaseolus lunatus samples to solve metabolic diseases. The evaluation of the chemical compositions and glycemic index (GI) of both seeds were carried out using standard methods. Phytochemical screening conducted on the seeds showed the presence of tannin, saponin, alkaloid and flavonoids in both samples. The results of antioxidant properties of the seeds showed that Phaseolu slunatus Original Research Article Adekunle et al.; Asian J. 55 and Lablab purpureushave Vitamin C (35.01 ± 0.02 and8.75± 0.03)mg/g, ferric reducing property (20.54 ± 0.02and 12.75 ± 0.03)mg/g, phenol (2.02 ± 0.02 and 2.05 ± 0.02)mg/g, flavonoids (3.47 ± 0.11 and3.22 ± 0.02) % andfree radical scavenging property (46.52 ±0.05 and 60.16 ±0.32)% respectively.The anti-nutrient results showed tannin (1.07 ± 0.01 and 1.22 ± 0.02)%, saponin (4.66 ± 0.05 and 5.15 5.15 ± 0.05)%, oxalate (3.20 ± 0.19 and 5.19 ± 0.19)mg/g, phytate(6.51 ± 0.01 and 2.64 ± 0.01) % for Lablab purpureus and Phaseoluslunatusseeds are respectively.The glycemic indices observed are (50.86 and 58.21)% forLablab purpureus and Phaseoluslunatusseeds respectively. The findings revealed that both seeds possessed good nutritional quality required in human diet together with adequate antioxidant properties plus low and medium glycemic indices that could help in fighting various cardiovascular diseases and prove them to be good sources of neutraceuticals required for a healthy living especially in diabetic patients.
The unique properties of resistant starch (RS) have made it applicable in the formulation of a broad range of functional foods. The physicochemical properties of RS play a crucial role in its applications. Recently, flow field-flow fractionation (FlFFF) has attracted increasing interest in the separation and characterization of different categories of RS. In this review, an overview of the theory behind FlFFF is introduced, and the controllable factors, including FlFFF channel design, sample separation conditions, and the choice of detector, are discussed in detail. Furthermore, the applications of FlFFF for the separation and characterization of RS at both the granule and molecule levels are critically reviewed. The aim of this review is to equip readers with a fundamental understanding of the theoretical principle of FlFFF and to highlight the potential for expanding the application of RS through the valuable insights gained from FlFFF coupled with multidetector analysis.
In most tropical countries, carbohydrate-based agricultural products occur in large quantities. Wider utilization of local starch crops will offer various economic and ecological advantages. Local starch crops can be a catalyst for rural industrial development and eventually open up new markets. The potential glucose yield from the typical Indonesian starches (edible canna, arrowroot, sago, and sweet potato) using lower dosage of cold-starch hydrolyzing enzyme preparation Stargen™ 002 was compared with that of corn and potato. The glucose equivalent yield reached 88.4 g/L and 86.3 g/L after 24 h of hydrolysis when 40% (w/v) raw sago and sweet potato starches were used, respectively, as compared to corn starch (89.6 g/L). While arrowroot and edible canna gave much lower amounts (53.3 g/L and 39.7 g/L, respectively). This study demonstrates that sago and sweet potato starches may provide interesting alternatives to corn starch in a cold hydrolysis conversion process of starch into glucose.
Approximately 35% of rapeseed meal (RSM) dry matter (DM) are carbohydrates, half of which are water-soluble carbohydrates. The cell wall of rapeseed meal contains arabinan, galactomannan, homogalacturonan, rhamnogalacturonan I, type II arabinogalactan, glucuronoxylan, XXGG-type and XXXG-type xyloglucan, and cellulose. Glycoside hydrolases including in the degradation of RSM carbohydrates are α-L-Arabinofuranosidases (EC 3.2.1.55), endo-α-1,5-L-arabinanases (EC 3.2.1.99), Endo-1,4-β-mannanase (EC 3.2.1.78), β-mannosidase (EC 3.2.1.25), α-galactosidase (EC 3.2.1.22), reducing-end-disaccharide-lyase (pectate disaccharide-lyase) (EC 4.2.2.9), (1 → 4)-6-O-methyl-α-D-galacturonan lyase (pectin lyase) (EC 4.2.2.10), (1 → 4)-α-D-galacturonan reducing-end-trisaccharide-lyase (pectate trisaccharide-lyase) (EC 4.2.2.22), α-1,4-D-galacturonan lyase (pectate lyase) (EC 4.2.2.2), (1 → 4)-α-D-galacturonan glycanohydrolase (endo-polygalacturonase) (EC 3.2.1.15), Rhamnogalacturonan hydrolase, Rhamnogalacturonan lyase (EC 4.2.2.23), Exo-β-1,3-galactanase (EC 3.2.1.145), endo-β-1,6-galactanase (EC 3.2.1.164), Endo-β-1,4-glucanase (EC 3.2.1.4), α-xylosidase (EC 3.2.1.177), β-glucosidase (EC 3.2.1.21) endo-β-1,4-glucanase (EC 3.2.1.4), exo-β-1,4-glucanase (EC 3.2.1.91), and β-glucosidase (EC 3.2.1.21). In conclusion, this review summarizes the chemical and nutritional compositions of RSM, and the microbial degradation of RSM cell wall carbohydrates which are important to allow to develop strategies to improve recalcitrant RSM carbohydrate degradation by the gut microbiota, and eventually to improve animal feed digestibility, feed efficiency, and animal performance.
In this work, a valorization of the starch stemming from downgraded potatoes was approached through the preparation of starch nanoparticles using different physical methods, namely liquid and supercritical carbon dioxide, high energy ball milling (HEBM), and ultrasonication on the one hand and enzymatic hydrolysis on the other hand. Starch nanoparticles are beneficial as a reinforcement in food packaging technology as they enhance the mechanical and water vapor resistance of polymers. Also, starch nanoparticles are appropriate for medical applications as carriers for the delivery of bioactive or therapeutic agents. The obtained materials were characterized using X-ray diffraction as well as scanning and transmission electron microscopies (SEM and TEM), whereas the hydrolysates were analyzed using size exclusion chromatography coupled with pulsed amperometric detection (SEC-PAD). The acquired results revealed that the physical modification methods led to moderate alterations of the potato starch granules’ size and crystallinity. However, enzymatic hydrolysis conducted using Pullulanase enzyme followed by nanoprecipitation of the hydrolysates allowed us to obtain very tiny starch nanoparticles sized between 20 and 50 nm, much smaller than the native starch granules, which have an average size of 10 μm. The effects of enzyme concentration, temperature, and reaction medium pH on the extent of hydrolysis in terms of the polymer carbohydrates’ fractions were investigated. The most promising results were obtained with a Pullulanase enzyme concentration of 160 npun/g of starch, at a temperature of 60 °C in a pH 4 phosphate buffer solution resulting in the production of hydrolysates containing starch polymers with low molecular weights corresponding mainly to P-10, P-5, and fractions with molecular weights lower than P-5 Pullulan standards.
Pulses provide economic and health benefits to people in many countries around the world; however, their adoption in western diets, particularly in processed and formulated foods, is limited. One strategy to increase the level of pulses in western diets is to improve pulse accessibility to the ready‐to‐eat (RTE) food market sector. Pulses have compositional and structural differences when compared to cereals and behave differently during processing. While there have been numerous studies on pulses processed using traditional processing methods, there are limited studies describing processing of pulses as a major ingredient in RTE forms such as flakes. To understand the full processing potential of pulses, systematic studies are required using commercial‐scale RTE pilot processing equipment coupled with fundamental property determination techniques to evaluate the effects of processing and pulse material on pulse flake attributes. In‐depth studies of pulse properties and their processability are likely to result in the production of high‐quality pulse‐based foods with superior health benefits. This review explores the current and potential opportunities for processing pulses with a focus on flake products. The roles of pulse type and major structure‐forming components such as fiber, carbohydrates, and proteins on end‐product quality of processed pulses are discussed.
Starch is the most abundant glycemic carbohydrate in the human diet. Consumption of starch‐rich food products that elicit high glycemic responses has been linked to the occurrence of noncommunicable diseases such as cardiovascular disease and diabetes mellitus type II. Understanding the structural features that govern starch digestibility is a prerequisite for developing strategies to mitigate any negative health implications it may have. Here, we review the aspects of the fine molecular structure that in native, gelatinized, and gelled/retrograded starch directly impact its digestibility and thus human health. We next provide an informed guidance for lowering its digestibility by using specific enzymes tailoring its molecular and three‐dimensional supramolecular structure. We finally discuss in vivo studies of the glycemic responses to enzymatically modified starches and relevant food applications. Overall, structure–digestibility relationships provide opportunities for targeted modification of starch during food production and improving the nutritional profile of starchy foods.
Beta (β)-glucan (BG) from cereal grains is associated with lowering post-prandial blood glucose but the precise mechanism is not well-elucidated. The main aim of this study was to understand the mechanism through which BG from barley affects post-prandial glycemic response. Waffles containing 0, 1, 2, and 3 g barley BG and the same amount of available carbohydrate (15 g) were fed to the TIM-1 dynamic gastrointestinal digestion system to study the effect of BG on starch hydrolysis. Intestinal acetone powder and Xenopus laevis oocytes were used to study BG's effect on mammalian intestinal α-glucosidase and glucose transporters. The presence of BG did not significantly affect the in vitro starch digestion profiles of waffles suggesting that BG does not affect α-amylase activity. Intestinal α-glucosidase and glucose transport activities were significantly (p < 0.0001) inhibited in the presence of barley BG. Interestingly, BG viscosity did not influence α-amylase, α-glucosidase, GLUT2, and SGLT1 activities. This study provides the first evidence for the mechanism by which BG from barley attenuates post-prandial glycemic response is via alteration of α-glucosidase, GLUT2, and SGLT1 activity, but not amylolysis of starch. The decrease in post-prandial blood glucose in the presence of BG is likely a consequence of the interaction between BG and membrane active proteins (brush border enzymes and glucose transporters) as opposed to the commonly held hypothesis that increased viscosity caused by BG inhibits starch digestion.
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