|Content:||660 assays per kit|
Short term stability: 2-8oC,
Long term stability: See individual component labels
|Stability:||> 2 years under recommended storage conditions|
|Linear Range:||4 to 100 μg of glucose per assay|
|Limit of Detection:||100 mg/L|
|Reaction Time (min):||~ 20 min|
|Application examples:||Wine, beer, fruit juices, soft drinks, milk, jam, dietetic foods, bakery products, candies, fruit and vegetables, tobacco, cosmetics, pharmaceuticals, feed, paper and other materials (e.g. biological cultures, samples, etc.).|
|Method recognition:||Widely used and accepted in clinical chemistry and food analysis|
The D-Glucose test kit contains high purity reagents for the measurement and analysis of D-glucose in cereal extracts and for use in combination with other Megazyme kits.
See more related mono/disaccharide assay kit products.
- All reagents stable for > 12 months after preparation
- Very competitive price (cost per test)
- Simple format
- Standard included
Diastatic power and maltose value: a method for the measurement of amylolytic enzymes in malt.
Charmier, L. M., McLoughlin, C. & McCleary, B. V. (2021). Journal of the Institute of Brewing, In Press.
A simple method for measurement of the amylolytic activity of malt has been developed and fully evaluated. The method, termed the Maltose Value (MV) is an extension of previously reported work. Here, the MV method has been studied in detail and all aspects of the assay (sample grinding and extraction, starch hydrolysis, maltose hydrolysis and determination as glucose) have been optimised. The method is highly correlated with other dextrinising power methods. The MV method involves extraction of malt in 0.5% sodium chloride at 30°C for 20 minutes followed by filtration; incubation of an aliquot of the undiluted filtrate with starch solution (pH 4.6) at 30°C for 15 min; termination of reaction with sodium hydroxide solution; dilution of sample in an appropriate buffer; hydrolysis of maltose with a specific α-glucosidase; glucose determination and activity calculation. Unlike all subsequent reducing sugar methods, the maltose value method measures a defined reaction product, maltose, with no requirement to use equations to relate analytical values back to Lintner units. The maltose value method is the first viable method in 130 years that could effectively replace the 1886 Lintner method.Hide Abstract
Measurement of available carbohydrates in cereal and cereal products, dairy products, vegetables, fruit and related food products and animal feeds: First Action 2020.07.
McCleary, B. V. & McLoughlin, C. (2021). Journal of AOAC International, qsab019.
Background: The level of available carbohydrates in our diet is directly linked to two major diseases; obesity and Type II diabetes. Despite this, to date there is no method available to allow direct and accurate measurement of available carbohydrates in human and animal foods. Objective: The aim of this research was to develop a method that would allow simple and accurate measurement of available carbohydrates, defined as non-resistant starch, maltodextrins, maltose, isomaltose, sucrose, lactose, glucose, fructose and galactose. Method: Non-resistant (digestible) starch is hydrolysed to glucose and maltose by pancreatic α-amylase and amyloglucosidase at pH 6.0 with shaking or stirring at 37°C for 4 h. Sucrose, lactose, maltose and isomaltose are completely hydrolyzed by specific enzymes to their constituent monosaccharides, which are then measured using pure enzymes in a single reaction cuvette. Results: A method has been developed that allows the accurate measurement of available carbohydrates in all cereal, vegetable, fruit, food, and feed products, including dairy products. Conclusions: A single-laboratory validation was performed on a wide range of food and feed products. The inter-day repeatability (%RSDr) was <3.58% (w/w) across a range of samples containing 44.1 to 88.9% available carbohydrates. The LOD and LOQ obtained were 0.054% (w/w) and 0.179% (w/w), respectively. The method is all inclusive, specific, robust and simple to use. Highlights: A unique method has been developed for the direct measurement of available carbohydrates, entailing separate measurement of glucose, fructose and galactose; information of value in determining the glycemic index of foods.Hide Abstract
Measurement of Starch: Critical evaluation of current methodology.
McCleary, B. V., Charmier, L. M. J. & McKie, V. A. (2018). Starch‐Stärke, 71(1-2), 1800146.
Most commonly used methods for the measurement of starch in food, feeds and ingredients employ the combined action of α‐amylase and amyloglucosidase to hydrolyse the starch to glucose, followed by glucose determination with a glucose oxidase/peroxidase reagent. Recently, a number of questions have been raised concerning possible complications in starch analytical methods. In this paper, each of these concerns, including starch hydrolysis, isomerisation of maltose to maltulose, effective hydrolysis of maltodextrins by amyloglucosidase, enzyme purity and hydrolysis of sucrose and β‐glucans have been studied in detailed. Results obtained for a range of starch containing samples using AOAC Methods 996.11 and 2014 .10 are compared and a new simpler format for starch measurement is introduced. With this method that employs a thermostable α-amylase (as distinct from a heat stable α-amylase) which is both stable and active at 100°C and pH 5.0, 10 samples can be analysed within 2 h, as compared to the 6 h required with AOAC Method 2014.10.Hide Abstract
Megazyme “advanced” wine test kits general characteristics and validation.
Charnock, S. J., McCleary, B. V., Daverede, C. & Gallant, P. (2006). Reveue des Oenologues, 120, 1-5.
Many of the enzymatic test kits are official methods of prestigious organisations such as the Association of Official Analytical Chemicals (AOAC) and the American Association of Cereal Chemists (AACC) in response to the interest from oenologists. Megazyme decided to use its long history of enzymatic bio-analysis to make a significant contribution to the wine industry, by the development of a range of advanced enzymatic test kits. This task has now been successfully completed through the strategic and comprehensive process of identifying limitations of existing enzymatic bio-analysis test kits where they occurred, and then using advanced techniques, such as molecular biology (photo 1), to rapidly overcome them. Novel test kits have also been developed for analytes of emerging interest to the oenologist, such as yeast available nitrogen (YAN; see pages 2-3 of issue 117 article), or where previously enzymes were simply either not available, or were too expensive to employ, such as for D-mannitol analysis.Hide Abstract
Grape and wine analysis: Oenologists to exploit advanced test kits.
Charnock, S. C. & McCleary, B. V. (2005). Revue des Enology, 117, 1-5.
It is without doubt that testing plays a pivotal role throughout the whole of the vinification process. To produce the best possible quality wine and to minimise process problems such as “stuck” fermentation or troublesome infections, it is now recognised that if possible testing should begin prior to harvesting of the grapes and continue through to bottling. Traditional methods of wine analysis are often expensive, time consuming, require either elaborate equipment or specialist expertise and frequently lack accuracy. However, enzymatic bio-analysis enables the accurate measurement of the vast majority of analytes of interest to the wine maker, using just one piece of apparatus, the spectrophotometer (see previous issue No. 116 for a detailed technical review). Grape juice and wine are amenable to enzymatic testing as being liquids they are homogenous, easy to manipulate, and can generally be analysed without any sample preparation.Hide Abstract
Digestibility and structure changes of rice starch following co-fermentation of yeast and Lactobacillus strains.
Tu, Y., Huang, S., Chi, C., Lu, P., Chen, L., Li, L., & Li, X. (2021). International Journal of Biological Macromolecules, 184, 530-537.
Rice is sometimes fermented with microorganisms to develop health-promoting foods, but the contribution of a short-term fermentation (a necessary step for fermented rice cake-preparation) to properties of rice starch is not resolved yet. The effects of microorganism fermentation with different amount of starter cultures on multi-scale structures and digestibility of rice starch were investigated. The amount of starter cultures significantly affected structures and digestibility of fermented starch. The fermentation with a lower amount of starter cultures induced starch degradation (corrosion of starch granules, reduction of lamellar orders and compactness, decrease in crystallinity, double helix, short ranger-ordered structures, and molar mass) and a slightly reassembly, which increased the content of slowly digestible starch (SDS). While, the fermentation produced more starch fractions with Mw between 0.60 × 107 g/mol and 1.50 × 107 g/mol as the amount of starter cultures increased, and these starch molecules tended to reassemble and form more ordered multi-scale structures including double helical and short range-ordered structures, starch lamellar orders and compactness, which elevated SDS content. The SDS content of fermented starchy foods could be improved via controlling starch reassembly and multi-scale ordered structures through modulating the amount of starter cultures during fermentation.Hide Abstract
Effect of granule size on the structure and digestibility of jackfruit seed starch.
Dong, S., Fang, G., Luo, Z. & Gao, Q. (2021). Food Hydrocolloids, 106964.
Jackfruit seed starch (JSS), maize starch (MS) and potato starch (PS) were fractionated and separated by glycerol-assisted centrifugal sedimentation based on their size. The digestibility and structure characteristics of the fractionated starch granules were analyzed. Different starch fractions exhibited different particle morphology. There was a significant increase in the resistant starch (RS) content and relative crystallinity (RC) of the fractionated starches with the increasing granule size. The different-sized fractions of JSS, MS and PS possessed similar crystalline type and the value of R1047/1022, respectively. However, the effect of granule size on the amylose content (AC) of the same starch type was mainly manifested difference in the large- and small-sized granules. Furthermore, for all the starch samples, JSS showed the smallest granules, the highest short-range ordered level and the value of RC. Compared with MS and PS, higher resistance to digestion was shown on JSS.Hide Abstract
Functional and nutritional properties of roasted semolina porridge with ghee and monoglyceride.
Oladiran, D. A. & Emmambux, N. M. (2021). Food Bioscience, 42, 101156.
The effect of addition of monoglyceride or ghee to semolina followed by pan roasting on functional and thermal properties of semolina porridge were investigated. The addition of lipids produced gels with softer textures. Roasted semolina and monoglyceride had significantly (p < 0.05) lower viscosity compared to roasted semolina with ghee and roasted semolina only. Addition of lipid lowered starch digestibility of semolina porridge. The x-ray pattern of roasted semolina only and roasted semolina with ghee or monoglyceride showed a combination of A and V-patterns with the V-pattern indicating the formation of amylose-lipid complex between starch and added/endogenous lipids. This was confirmed by DSC thermograms where dissociation peaks corresponding to type I and type II amylose-lipid complexes were observed. This result shows that modification of starch with lipids remains a plausible way of improving its functional and nutritional properties.Hide Abstract
In vitro fecal fermentation outcomes of starch-lipid complexes depend on starch assembles more than lipid type.
Zhou, Q., Fu, X., Dhital, S., Zhai, H., Huang, Q. & Zhang, B. (2021). Food Hydrocolloids, 120, 106941.
The human gut microbiota are mostly regulated and stabilized by available macro-nutrients (carbohydrates, proteins and lipids) excursed to colonic fermentation. Resistant starch (RS) has been shown to be metabolized to specific short-chain fatty acids (SCFAs) in the colon associated with proven health benefits. However, the in vitro fecal fermentation outcomes of starch-lipid complexes (i.e., type 5 RS) and its regulation mechanism on gut microbiota are least understood. In this study, debranched high-amylose maize starches complexed with saturated fatty acids (SFAs) were in-vitro fermented by human fecal inocula and evaluated for fermentation rate, beneficial metabolite profiles as well as changes in microbiota composition. The fermentation rate of all starch-lipid complexes tested was similar and slow throughout the whole fermentation process. At the end of fermentation, the propionate concentration was significantly different between starch-lipid complex samples prepared with various SFAs. No significant difference was observed at the first three fermentation time points for the butyrate concentration, with the final concentration range of 27-33 mM. Starch-lipid complexes significantly increased the relative abundance of some beneficial gut microbiota such as Roseburia and Prevotella, and showed a closer distance with high-amylose maize starch and debranched starch rather than SFAs from the principal component analysis. Furthermore, compared with starch-lipid complexes, lauric acid and myristic acid promoted the increase of some apparently harmful gut microbiota, including Bilophila, Fusobacterium and Dialister, while palmitic acid and stearic acid did not show similar phenomenon.Hide Abstract
Expected glycemic impact and probiotic stimulating effects of whole grain flours of buckwheat, quinoa, amaranth and chia.
Arslan-Tontul, S., Uslu, C. C., Mutlu, C. & Erbaş, M. (2021). Journal of Food Science and Technology, 1-8.
Chia, amaranth, quinoa and buckwheat grains have been widely used in food formulations because of their high and balanced nutritional properties. Since all grains are not equally nutritious, there is a requirement for comparing the health-related effects and processing performance of a variety of whole grains. The expected glycemic index (eGI) flours of chia was determined to be quite low, and flours except quinoa can be classified as low GI foods. The highest resistant starch (RS) content (4.76 g/100 g) was found in amaranth flour, and it was followed by buckwheat (1.27 g/100 g). The amaranth had the highest stimulation effect on the growth of probiotics and increased the count of L. acidophilus and B. bifidum as 4.57 and 2.26 log CFU/ml, respectively. Moreover, chia flour showed a positive effect on the growth of L. acidophilus whereas it negatively affected B. bifidum compared to the control. A significant correlation was detected between rapidly available glucose content and eGI. On the other hand, a significant relationship between RS and the growth rate of probiotics was reported.Hide Abstract
Mechanistic studies of starch retrogradation and its effects on starch gel properties.
Liu, X., Chao, C., Yu, J., Copeland, L. & Wang, S. (2021). Food Hydrocolloids, 106914.
The influence of residual short-range molecular order on the mechanism of starch retrogradation was examined by measuring functional properties of retrograding starch gels that were prepared by heating starch with different amounts of water at 100°C. Analyses using X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and laser confocal micro-Raman (LCM-Raman) spectroscopy showed that as short-range molecular range in the gelatinized starch decreased, so did long- and short-range molecular order, gel firmness, water mobility and susceptibility to in vitro enzymic digestion of the corresponding starch as it retrograded over time periods ranging from one to 21 days. The rate and extent of these changes were controlled by the amount of residual short-range molecular order in the starch after gelatinization, which in turn, was a function of the amount of water used for gelatinization. Starch gelatinized with 50-70% water formed had residual short-range molecular order and retrograded more quickly to form stronger gels, whereas starch gelatinized with 75 and 80% retained little structural order and retrograded more slowly, forming softer gels in which the starch crystallites were better-defined. Our study provides new insights into the mechanism of starch retrogradation and its effects on functional properties of retrograded starch gels, which is likely to be of interest for starch in foods and other applications.Hide Abstract
Investigation of starch functionality and digestibility in white wheat bread produced from a recipe containing added maltogenic amylase or amylomaltase.
Korompokis, K., Deleu, L. J., De Brier, N. & Delcour, J. A. (2021). Food Chemistry, 130203.
In the crumb of fresh white wheat bread, starch is fully gelatinized. Its molecular and three-dimensional structure are major factors limiting the rate of its digestion. The aim of this study was to in situ modify starch during bread making with starch-modifying enzymes (maltogenic amylase and amylomaltase) and to investigate the impact thereof on bread characteristics, starch retrogradation and digestibility. Maltogenic amylase treatment increased the relative content of short amylopectin chains (degree of polymerization ≤ 8). This resulted in lower starch retrogradation and crumb firmness upon storage, and reduced extent (up to 18%) of in vitro starch digestion for fresh and stored breads. Amylomaltase only modestly shortened amylose chains and had no measurable impact on amylopectin structure. Modification with this enzyme led to slower bread crumb firming but did not influence starch digestibility.Hide Abstract
Beta-Glucan From Barley Attenuates Post-prandial Glycemic Response by Inhibiting the Activities of Glucose Transporters but Not Intestinal Brush Border Enzymes and Amylolysis of Starch.
Malunga, L. N., Ames, N., Zhouyao, H., Blewett, H. & Thandapilly, S. J. (2021). Frontiers in Nutrition, 8, 628571.
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.Hide Abstract
Effect of whole quinoa flour substitution on the texture and in vitro starch digestibility of wheat bread.
Wang, X., Lao, X., Bao, Y., Guan, X. & Li, C. (2021). Food Hydrocolloids, 119, 106840.
Wheat breads are popular staples, while the ones with desirable textural attributes frequently have a high glycemic index value. The inclusion of different amount of whole quinoa flour (WQF) in wheat breads was investigated in this study, aiming to develop nutritionally fortified breads with both slower starch digestibility and desirable textural attributes. Results showed that although addition of WQF decreased the specific volume of wheat breads by affecting gluten network of dough, hardness and chewiness (the most important attributes affecting consumer acceptability) of those wheat breads were not significantly affected with an ≤ 20% of WQF substitution. On the other hand, addition of quinoa flour affected starch digestibility of breads. A 17% reduction of maximum starch digestion amount was reached by the addition of 40% WQF compared to wheat breads. By fitting starch digestograms to logarithm of slope (LOS) and combination of parallel and sequential (CPS) first-order kinetics model, it showed that two starch digestible fractions with distinct rate constants were existed in the bread system. Scanning electron microscope results showed that A type wheat starch granules were largely gelatinized, while B type wheat starch and quinoa starch granules were relatively intact and wrapped in the protein-sugar-oil film after baking. It could rationalize the occurrence of two different starch digestible fractions. This study suggests that increasing the ratio of B to A type wheat starch or addition of quinoa starch granules has potential to develop breads with both low glycemic index values and desirable textural attributes.Hide Abstract
Inhibition of in vitro enzymatic starch digestion by coffee extract.
Li, X., Cai, J., Yu, J., Wang, S., Copeland, L. & Wang, S. (2021). Food Chemistry, 358, 129837.
There is evidence that moderate coffee consumption is beneficial in the prevention of type 2 diabetes, however, the underlying mechanism is not understood. In this study, the effects of an extract of ground coffee on the in vitro enzymatic digestion of starch were investigated. The coffee extract decreased the rate and extent of starch digestion, with kinetic analysis showing that the extract reduced the binding affinity of the enzymes for the substrate and their catalytic turnover. Fluorescence quenching indicated that the coffee extract formed complexes with the digestive enzymes through a static quenching mechanism. Ultraviolet absorption and circular dichroism spectra of the digestive enzymes confirmed that the coffee extract decreased the proportion of β-sheet structures in the enzymes. Therefore, we conclude that compounds in the soluble coffee extract can interact with porcine pancreatic amylase and amyloglucosidase causing inhibition of the enzymes and decreasing in vitro starch digestion.Hide Abstract
Digestibility of resistant starch type 3 is affected by crystal type, molecular weight and molecular weight distribution.
Klostermann, C. E., Buwalda, P. L., Leemhuis, H., de Vos, P., Schols, H. A. & Bitter, J. H. (2021). Carbohydrate Polymers, 265, 118069.
Resistant starch type 3 (RS-3) holds great potential as a prebiotic by supporting gut microbiota following intestinal digestion. However the factors influencing the digestibility of RS-3 are largely unknown. This research aims to reveal how crystal type and molecular weight (distribution) of RS-3 influence its resistance. Narrow and polydisperse α-glucans of degree of polymerization (DP) 14-76, either obtained by enzymatic synthesis or debranching amylopectins from different sources, were crystallized in 12 different A- or B-type crystals and in vitro digested. Crystal type had the largest influence on resistance to digestion (A >>> B), followed by molecular weight (Mw) (high DP >> low DP) and Mw distribution (narrow disperse > polydisperse). B-type crystals escaping digestion changed in Mw and Mw distribution compared to that in the original B-type crystals, whereas A-type crystals were unchanged. This indicates that pancreatic α-amylase binds and acts differently to A- or B-type RS-3 crystals.Hide Abstract
Effect of amino acids composing rice protein on rice starch digestibility.
Lu, X., Chang, R., Lu, H., Ma, R., Qiu, L. & Tian, Y. (2021). LWT, 146, 111417.
During the digestion of rice, proteins are among the main rice components and are hydrolyzed into amino acids by enzymes. In this study, we evaluated the influence of free amino acids liberated from rice proteins during digestion on rice starch digestibility for exploring the starch digestion mechanisms in the presence of rice protein. The results showed that all the amino acids inhibited the activity of porcine pancreatic α-amylase. Moreover, glutamate (Glu) displayed a mixed-type suppression of porcine pancreatic α-amylase, with a half-inhibitory concentration of 11.67 mg/mL. Amino acids were complexed with rice starch through heat-moisture treatment and the slowly digestible starch content significantly increased from 29.6 to 41.3 g/100 g. The interaction between amino acids and starch increased the ordered and aggregated structure of rice starch. Therefore, the enzyme inhibition and starch structure changes induced by amino acids contributed to the mitigation of starch digestion. These findings will improve our understanding of the relationship between amino acids and starch digestion and provide a theoretical basis for preparing starch-based food with a low glycemic index.Hide Abstract
The influence of α-1, 4-glucan substrates on 4, 6-α-D-glucanotransferase reaction dynamics during isomalto/malto-polysaccharide synthesis.
Klostermann, C. E., van der Zaal, P. H., Schols, H. A., Buwalda, P. L. & Bitter, J. H. (2021). International Journal of Biological Macromolecules, 181, 762-768.
Starch-based isomalto/malto-polysaccharides (IMMPs) are soluble dietary fibres produced by the incubation of α-(1 → 4) linked glucans with the 4,6-α-glucanotransferase (GTFB) enzyme. In this study, we investigated the reaction dynamics of the GTFB enzyme by using isoamylase debranched starches as simplified linear substrates. Modification of α-glucans by GTFB was investigated over time and analysed with 1H NMR, HPSEC, HPAEC combined with glucose release measurements. We demonstrate that GTFB modification of linear substrates followed a substrate/acceptor model, in which α-(1 → 4) linked glucans DP ≥ 6 functioned as donor substrate, and α-(1 → 4) linked malto-oligomers DP < 6 functioned as acceptor. The presence of α-(1 → 4) linked malto-oligomers DP < 6 resulted in higher GTFB transferase activity, while their absence resulted in higher GTFB hydrolytic activity. The information obtained in this study provides a better insight into GTFB reaction dynamics and will be useful for α-glucan selection for the targeted synthesis of IMMPs in the future.Hide Abstract
Physicochemical properties of turanose and its potential applications as a sucrose substitute.
Han, D. J., Lee, B. H. & Yoo, S. H. (2021). Food Science and Biotechnology, 30(3), 433-441.
Among the structural isomers of sucrose, turanose has been considered as one of good candidates as novel sweetener due to its mild taste, low calorie, and anti-cariogenicity. Here, various physicochemical properties of turanose, such as solubility, temperature and pH stabilities, viscosity, non-enzymatic browning reaction, and dynamic vapor sorption, were investigated by comparing them to those of other commercial sugars. Turanose did not significantly hydrolyze through the simulated digestion tract overall but in the artificial small intestinal environment specifically, turanose degraded by only 18% when sucrose was hydrolyzed by 36% after 4 h. In addition, physicochemical properties of turanose confirmed that it had a potential to replace sucrose due to similar or better product qualities as a food ingredient than other types of sugars with similar chemical structure. Thus, our study suggests that turanose can be applied as a functional sweetener or bulking agent in food processing.Hide Abstract