10 mL - 3,000 Units/mL or
40 mL - 3,000 Units/mL or
100 mL - 3,000 Units/mL or
100 mL - 750 Units/mL (ANKOM)
|Stability:||> 4 years at 4oC|
|Synonyms:||alpha-amylase; 4-alpha-D-glucan glucanohydrolase|
|Expression:||Purified from Bacillus licheniformis|
|Specificity:||endo-hydrolysis of α-1,4-D-glucosidic linkages in starch.|
|Specific Activity:||~ 55 U/mg (40oC, pH 6.5 on Ceralpha reagent)|
|Unit Definition:||One Unit of α-amylase is the amount of enzyme required to release one µmole of p-nitrophenol from blocked p-nitrophenyl-maltoheptaoside per minute (in the presence of excess α-glucosidase) at pH 6.0 and 40oC.|
|Application examples:||For use in Megazyme Total Starch and Dietary Fiber methods.|
|Method recognition:||EBC Method 6.5|
High purity α-Amylase (Bacillus licheniformis) for use in research, biochemical enzyme assays and in vitro diagnostic analysis.
For use in Megazyme Total Starch and Dietary Fiber methods, suitable for use at pH 6.5 and above.
E-BLAAM-A-100mL specifically to be used with ANKOMTDF Dietary Fiber Analyzer.
Data booklets for each pack size are located in the Documents tab.
We offer other α-amylase in our list of Carbohydrate Active enZYme products.
Measurement of available carbohydrates, digestible, and resistant starch in food ingredients and products.
McCleary, B. V., McLoughlin, C., Charmier, L. M. J. & McGeough, P. (2019). Cereal Chemistry, 97(1), 114-137.
Background and objectives: The importance of selectively measuring available and unavailable carbohydrates in the human diet has been recognized for over 100 years. The levels of available carbohydrates in diets can be directly linked to major diseases of the Western world, namely Type II diabetes and obesity. Methodology for measurement of total carbohydrates by difference was introduced in the 1880s, and this forms the basis of carbohydrate determination in the United States. In the United Kingdom, a method to directly measure available carbohydrates was introduced in the 1920s to assist diabetic patients with food selection. The aim of the current work was to develop simple, specific, and reliable methods for available carbohydrates and digestible starch (and resistant starch). The major component of available carbohydrates in most foods is digestible starch. Findings: Simple methods for the measurement of rapidly digested starch, slowly digested starch, total digestible starch, resistant starch, and available carbohydrates have been developed, and the digestibility of phosphate cross‐linked starch has been studied in detail. The resistant starch procedure developed is an update of current procedures and incorporates incubation conditions with pancreatic α‐amylase (PAA) and amyloglucosidase (AMG) that parallel those used AOAC Method 2017.16 for total dietary fiber. Available carbohydrates are measured as glucose, fructose, and galactose, following complete and selective hydrolysis of digestible starch, maltodextrins, maltose, sucrose, and lactose to glucose, fructose, and galactose. Sucrose is hydrolyzed with a specific sucrase enzyme that has no action on fructo‐oligosaccharides (FOS). Conclusions: The currently described “available carbohydrates” method together with the total dietary fiber method (AOAC Method 2017.16) allows the measurement of all carbohydrates in food products, including digestible starch. Significance and novelty: This paper describes a simple and specific method for measurement of available carbohydrates in cereal, food, and feed products. This is the first method that provides the correct measurement of digestible starch and sucrose in the presence of FOS. Such methodology is essential for accurate labeling of food products, allowing consumers to make informed decisions in food selection.Hide Abstract
Measurement of α-amylase activity in white wheat flour, milled malt, and microbial enzyme preparations, using the ceralpha assay: Collaborative study.
McCleary, B. V., McNally, M., Monaghan, D. & Mugford, D. C. (2002). Journal of AOAC International, 85(5), 1096-1102.
This study was conducted to evaluate the method performance of a rapid procedure for the measurement of α-amylase activity in flours and microbial enzyme preparations. Samples were milled (if necessary) to pass a 0.5 mm sieve and then extracted with a buffer/salt solution, and the extracts were clarified and diluted. Aliquots of diluted extract (containing α-amylase) were incubated with substrate mixture under defined conditions of pH, temperature, and time. The substrate used was nonreducing end-blocked p-nitrophenyl maltoheptaoside (BPNPG7) in the presence of excess quantities of thermostable α-glucosidase. The blocking group in BPNPG7 prevents hydrolysis of this substrate by exo-acting enzymes such as amyloglucosidase, α-glucosidase, and β-amylase. When the substrate is cleaved by endo-acting α-amylase, the nitrophenyl oligosaccharide is immediately and completely hydrolyzed to p-nitrophenol and free glucose by the excess quantities of α-glucosidase present in the substrate mixture. The reaction is terminated, and the phenolate color developed by the addition of an alkaline solution is measured at 400 nm. Amylase activity is expressed in terms of Ceralpha units; 1 unit is defined as the amount of enzyme required to release 1 µmol p-nitrophenyl (in the presence of excess quantities of α-glucosidase) in 1 min at 40°C. In the present study, 15 laboratories analyzed 16 samples as blind duplicates. The analyzed samples were white wheat flour, white wheat flour to which fungal α-amylase had been added, milled malt, and fungal and bacterial enzyme preparations. Repeatability relative standard deviations ranged from 1.4 to 14.4%, and reproducibility relative standard deviations ranged from 5.0 to 16.7%.Hide Abstract
McCleary, B. V. & Monaghan, D. (2000). “Proceedings of the Second European Symposium on Enzymes in Grain Processing”, (M. Tenkanen, Ed.), VTT Information Service, pp. 31-38.
Over the past 8 years, we have been actively involved in the development of simple and reliable assay procedures, for the measurement of enzymes of interest to the cereals and related industries. In some instances, different procedures have been developed for the measurement of the same enzyme activity (e.g. α-amylase) in a range of different materials (e.g. malt, cereal grains and fungal preparations). The reasons for different procedures may depend on several factors, such as the need for sensitivity, ease of use, robustness of the substrate mixture, or the possibility for automation. In this presentation, we will present information on our most up-to-date procedures for the measurement of α-amylase, endo-protease, β-glucanase and β-xylanase, with special reference to the use of particular assay formats in particular applications.Hide Abstract
Gibson, T. S., Al Qalla, H. & McCleary, B. V. (1992). Journal of Cereal Science, 15(1), 15-27.
An improved enzymic method for the determination of starch damage in wheat flour has been developed and characterized. The proposed method is simple and reliable, and enables up to 20 samples to be measured in duplicate in 2 h. A single assay takes approximately 40 min. The assay protocol is in two phases. In the first, the flour sample is incubated with purified fungal alpha-amylase to liberate damaged starch granules as soluble oligosaccharides. After centrifugation, the oligosaccharides in the supernatant are hydrolysed by amyloglucosidase to glucose in phase 2. The glucose is then quantified with a glucose oxidase/peroxidase reagent. The proposed method therefore avoids potential errors associated with existing standard assays, which employ unpurified amylase preparations and non-specific reducing group methods to quantify the hydrolytic products. Despite the use of purified assay components, the proposed starch damage method did not exhibit an absolute end-point to the action of alpha-amylase in phase 1. This was due to a low rate of hydrolysis of undamaged granules, and is a feature of enzymic methods for starch damage determination. Other amylolytic enzymes, including beta-amylase, isoamylase and pullulanase, and combinations of these enzymes, were evaluated as alternatives to alpha-amylase in the proposed method. These enzymes, when used alone, gave no benefits over the use of alpha-amylase. When used in combination with alpha-amylase, there was a synergistic action on undamaged granules. A test kit based on the assay format described in this paper is the subject of an international interlaboratory evaluation.Hide Abstract
Sheehan, H. & McCleary, B. V. (1988). Biotechnology Techniques, 2(4), 289-292.
A procedure for the measurement of fungal and bacterial α-amylase in crude culture filtrates and commercial enzyme preparations is described. The procedure employs end-blocked (non-reducing end) p-nitrophenyl maltoheptaoside in the presence of amyloglucosidase and α-glucosidase, and is absolutely specific for α-amylase. The assay procedure is simple, reliable and accurate.Hide Abstract
Measurement of cereal α-Amylase: A new assay procedure.
McCleary, B. V. & Sheehan, H. (1987). Journal of Cereal Science, 6(3), 237-251.
A new procedure for the assay of cereal α-amylase has been developed. The substrate is a defined maltosaccharide with an α-linked nitrophenyl group at the reducing end of the chain, and a chemical blocking group at the non-reducing end. The substrate is completely resistant to attack by β-amylase, glucoamylase and α-glucosidase and thus forms the basis of a highly specific assay for α-amylase. The reaction mixture is composed of the substrate plus excess quantities of α-glucosidase and glucoamylase. Nitrophenyl-maltosaccharides released on action of α-amylase are instantaneously cleaved to glucose plus free p-nitrophenol by the glucoamylase and α-glucosidase, such that the rate of release of p-nitrophenol directly correlates with α-amylase activity. The assay procedure shows an excellent correlation with the Farrand, the Falling Number and the Phadebas α-amylase assay procedures.Hide Abstract
Effect of different fermentation condition on estimated glycemic Index, In Vitro starch digestibility, and textural and sensory properties of sourdough bread.
Demirkesen-Bicak, H., Arici, M., Yaman, M., Karasu, S. & Sagdic, O. (2021). Foods, 10(3), 514.
This study aimed to evaluate the influence of sourdough fermentation on the estimated glycemic index (eGI), in vitro starch digestibility, and textural and sensory properties of eight experimentally prepared sourdough breads. Wheat and whole wheat flour bread samples were produced under different fermentation conditions (25°C and 30°C) and fermentation methods (type-1 and type-2). In type-1 fermentation, sourdough was obtained via spontaneous fermentation. Indigenous strains (Lactobacillus brevis ELB99, Lactiplantibacillus plantarum ELB75, and Saccharomyces cerevisiae TGM55) were used for type-2 fermentation. Fermentation type and temperature significantly affected eGI, the hydrolysis index (HI), the starch fraction, and the textural properties of the samples (p < 0.05). The resistant starch (RS) content increased after fermentation, while rapidly digestible starch (RDS), HI, and eGI decreased. RS values were significantly higher in type-2 than in type-1 at the same temperature for both flour types (p < 0.05). At 25°C, RS values were higher in both fermentation types. In the white flour samples, eGI values were in the range of 60.8-78.94 and 62.10-78.94 for type-1 and type-2, respectively. The effect of fermentation type on eGI was insignificant (p < 0.05). In the whole flour samples, fermentation type and temperature significantly affected eGI (p < 0.05). The greatest eGI decreases were in whole wheat sourdough bread at 30°C using type-2 (29.74%). The 30°C and type-2 samples showed lower hardness and higher specific volume. This study suggests that fermentation type and temperature could affect the eGI and the textural and sensory properties of sourdough bread, and these factors should be considered during bread production. The findings also support the consumption of wheat and whole wheat breads produced by type-2 fermentation due to higher RS and slowly digestible starch (SDS) and lower RDS and eGI values.Hide Abstract
Changes in light spectra modify secondary compound concentrations and BVOC emissions of Norway spruce seedlings.
Kivimäenpää, M., Virjamo, V., Ghimire, R. P., Holopainen, J., Julkunen-Tiitto, R., Martz, F., Nissinen, K. & Riikonen, J. (2020). Canadian Journal of Forest Research, (ja).
Our objective was to study how changes in the light spectra affects growth, carbohydrate, chlorophyll, carotenoid, terpene, alkaloid and phenolic concentrations, and BVOC (biogenic volatile organic compound) emissions of Norway spruce (Picea abies) seedlings. This study was conducted during the growth of the third needle generation in plant growth chambers. Two light spectra with the main difference in proportion of blue light (400-500 nm) and equal photon flux densities were provided by LED (light-emitting diode) lamps: 1) control (white light + 12 % blue light) and 2) increased blue light (+B) (white light + 45% blue light). The +B treatment increased needle concentrations of total flavonoids and acetophenones. The major changes in the phenolic profile were an accumulation of astragalin derivatives and the aglycone of picein. +B decreased concentrations of the main alkaloid compound, epidihydropinidine, and it’s precursor, 2-methyl-6-propyl-1,6-piperideine, emission rates of limonene, myrcene and total monoterpenes, and concentrations of a few terpenoid compounds, mainly in stems. Growth, needle carbohydrates and pigments were not affected. The results suggest that supplemental blue light shifts carbon allocation between secondary metabolism routes, from alkaloid and terpenoid synthesis to flavonoid and acetophenone synthesis. The changes may affect herbivory and abiotic stress tolerance of Norway spruce.Hide Abstract
A chemical valorisation of melon peels towards functional food ingredients: Bioactives profile and antioxidant properties.
Gómez-García, R., Campos, D. A., Oliveira, A., Aguilar, C. N., Madureira, A. R. & Pintado, M. (2020). Food Chemistry, 335, 127579.
The goal of this work was to characterize the profile of bioactive compounds and the antioxidant activity of inodorus melon peels. Melon peels were divided into three fractions: a solid fraction with a higher content of carbohydrates (84.81%); a liquid fraction with a higher ash content (11.5%); and a pellet fraction with a higher protein content (34.90%). The structural carbohydrates study revealed a composition of cellulose (27.68%), hemicellulose (8.2%) and lignin (26.46%) in the solid fraction. The liquid fraction had the highest antioxidant activity based on results from DPPH, ABTS and ORAC assays. Flavones, hydroxybenzoic and hydroxycinnamic acids were the main phenolic classes found in all fractions. In addition, β-carotene, lutein, β-cryptoxanthin and violaxanthin had also been quantified. Melon fractions were rich in nutrients and bioactive substances and could be useful in the development of novel functional products, considering the growing market demand for safe and healthy food products.Hide Abstract
Cell wall architecture as well as chemical composition determines fermentation of wheat cell walls by a faecal inoculum.
Lu, S., Flanagan, B. M., Williams, B. A., Mikkelsen, D. & Gidley, M. J. (2020). Food Hydrocolloids, 107, 105858.
Grain cell walls are a common component of the human diet, and an important source of dietary fibre. They primarily consist of a cellulose matrix incorporating arabinoxylan (AX) and mixed linkage (1, 3)(1, 4)-β-glucan (MLG). In this study, cell walls isolated from wheat flour (WCW) were compared with a physical mixture (Mix) of the major WCW polysaccharides (AX, MLG and cellulose) in the proportions found in WCW. WCW, Mix and the individual polysaccharides were subjected to in vitro fermentation for 48 h with a porcine fecal inoculum. Each constituent in Mix was fermented to a similar extent as single-component substrates, indicated by the total amount of gas and short chain fatty acid (SCFA) produced. However, WCW showed a slower production of gas and SCFA and slower degradation of its non-cellulosic polysaccharides. This suggests that the architecture of WCW plays a critical role in determining the rate of fecal microbial fermentation.Hide Abstract
A comparison of the nutritional value of Einkorn, Emmer, Khorasan and modern wheat: whole grains, processed in bread, and population‐level intake implications.
Van Boxstael, F., Aerts, H., Linssen, S., Latré, J., Christiaens, A., Haesaert, G., Dierickx, I., Brusselle, J. & De Keyzer, W. (2020). Journal of the Science of Food and Agriculture, 100(11), 4108-4118.
Background: Interest in alternatives to the traditional wheat Triticum aestivum among farmers, millers, bakers, and consumers is increasing. The Altergrain project aimed to compare the Belgian‐soil cultivated Einkorn (1K), Emmer (EMM), Khorasan (KH), and modern wheat (MW) with respect to nutritional values of kernels, breads made from these cereals, and population‐level nutrient intake implications. Results: Ancient wheats 1K, EMM, and KH contain lower total carbohydrate content than MW. Further, ancient wheats are higher in both protein and crude ash content. Vitamin E levels in breads prepared using 1K and EMM were higher than those in MW, but those prepared from KH had lower vitamin E levels than MW. Breads prepared using ancient wheats have higher total phenol content (TPC) than those from MW. Baking caused a decrease in vitamin E and TPC in bread prepared from ancient wheat, the exception being the one prepared using KH, which had a higher TPC than MW. When replacing bread made from MW with those made from ancient grains, no differences were observed with respect to conformance with the Belgian Recommend Daily Requirements. Conclusions: Ancient wheats from Belgian soil are as nutritive as MWs even after being processed into bread. At the kernel level, nutritional differences are present, but only small differences are present in terms of nutritional intake when nutrition parameters are calculated for consumed bread.Hide Abstract
Cell Wall Compositional Analysis of Rice Culms.
Zhang, L., Zhang, B. & Zhou, Y. (2019). Bio-Protocol, 9(20), e3398.
The plant cell wall is a complicated network that is mainly constituted of polysaccharides, such as cellulose, hemicellulose and pectin. Many noncellulosic polysaccharides are further acetylated, which confers these polymers flexible physicochemical properties. Due to the significance of cell wall in plant growth and development, the analytic platform has been the focus for a long time. Here, we use internodes/culms, an important organ to provide mechanical support for rice plants, as an experimental sample to explore the method for cell wall composition analysis. The method includes preparation of cell wall residues, sequential extraction of polysaccharides, and measurement of cellulose. The procedure for acetate examination is also described. This method is applicable to determine the composition of individual cell wall polymers and the modifier acetates, and is suitable to identify cell wall relevant mutants based on the advantages in high throughput, precision and repeatability.Hide Abstract
Profiling Cell Wall Monosaccharides and Nucleotide‐Sugars from Plants.
Rautengarten, C., Heazlewood, J. L. & Ebert, B. (2019). Current protocols in Plant Biology, 4(2), e20092.
The cell wall is an intricate mesh largely composed of polysaccharides that vary in structure and abundance. Apart from cellulose biosynthesis, the assembly of matrix polysaccharides such as pectin and hemicellulose occur in the Golgi apparatus before being transported via vesicles to the cell wall. Matrix polysaccharides are biosynthesized from activated precursors or nucleotide sugars. The composition and assembly of the cell wall is an important aspect in plant development and plant biomass utilization. The application of anion‐exchange chromatography to determine the monosaccharide composition of the insoluble matrix polysaccharides enables a complete profile of all major sugars in the cell wall from a single run. While porous carbon graphite chromatography and tandem mass spectrometry delivers a sensitive and robust nucleotide sugar profile from plant extracts. Here we describe detailed methodology to quantify nucleotide sugars within the cell and profile the non‐cellulosic monosaccharide composition of the cell wall.Hide Abstract
Varietal differences in the effect of rice ageing on starch digestion.
Azizi, R., Capuano, E., Nasirpour, A., Pellegrini, N., Golmakani, M. T., Hosseini, S. M. H. & Farahnaky, A. (2019). Food Hydrocolloids, 95, 358-366.
The purpose of this study was to provide, for the first time, a comprehensive account of the potential effects of storage (37°C) on physicochemical properties and digestion behaviour of three highly consumed Iranian rice varieties (Hashemi, Domsiyah and Gohar). After ageing, the content of thiol groups was significantly reduced only in the case of Hashemi. The ageing process did not significantly change the rate and extent of starch digestion in Gohar and Domsiyah, but a clear reduction was observed in Hashemi. The results suggested that the changes in peptide subunit composition contribute to the potential efficiency of ageing for controlling rice digestion behaviour. This study suggests that varietal differences may play a major role in the effectiveness of ageing in modifying rice physicochemical properties and starch digestion dynamics. The results also indicated that starch digestibility didn't follow amylose content level and suggests the importance of other components on rice digestibility.Hide Abstract
Response of photosynthesis, growth and water relations of a savannah-adapted tree and grass grown across high to low CO2.
Quirk, J., Bellasio, C., Johnson, D. A. & Beerling, D. J. (2019). Annals of Botany, 124(1), 77-90.
Background and Aims: By the year 2100, atmospheric CO2 concentration ([CO2]a) could reach 800 ppm, having risen from ~200 ppm since the Neogene, beginning ~24 Myr ago. Changing [CO2]a affects plant carbon–water balance, with implications for growth, drought tolerance and vegetation shifts. The evolution of C4 photosynthesis improved plant hydraulic function under low [CO2]a and preluded the establishment of savannahs, characterized by rapid transitions between open C4-dominated grassland with scattered trees and closed forest. Understanding directional vegetation trends in response to environmental change will require modelling. But models are often parameterized with characteristics observed in plants under current climatic conditions, necessitating experimental quantification of the mechanistic underpinnings of plant acclimation to [CO2]a. Methods: We measured growth, photosynthesis and plant–water relations, within wetting–drying cycles, of a C3 tree (Vachellia karroo, an acacia) and a C4 grass (Eragrostis curvula) grown at 200, 400 or 800 ppm [CO2]a. We investigated the mechanistic linkages between trait responses to [CO2]a under moderate soil drying, and photosynthetic characteristics. Key results: For V. karroo, higher [CO2]a increased assimilation, foliar carbon:nitrogen, biomass and leaf starch, but decreased stomatal conductance and root starch. For Eragrostis, higher [CO2]a decreased C:N, did not affect assimilation, biomass or starch, and markedly decreased stomatal conductance. Together, this meant that C4 advantages in efficient water-use over the tree were maintained with rising [CO2]a. Conclusions: Acacia and Eragrostis acclimated differently to [CO2]a, with implications for their respective responses to water limitation and environmental change. Our findings question the carbon-centric focus on factors limiting assimilation with changing [CO2]a, how they are predicted and their role in determining productivity. We emphasize the continuing importance of water-conserving strategies in the assimilation response of savannah plants to rising [CO2]a.Hide Abstract
Butanol production from laccase-pretreated brewer’s spent grain.
Giacobbe, S., Piscitelli, A., Raganati, F., Lettera, V., Sannia, G., Marzocchella, A., & Pezzella, C. (2019). Biotechnology for Biofuels, 12(1), 1-8.
Background: Beer is the most popular alcoholic beverage worldwide. In the manufacture of beer, various by-products and residues are generated, and the most abundant (85% of total by-products) are spent grains. Thanks to its high (hemi)cellulose content (about 50% w/w dry weight), this secondary raw material is attractive for the production of second-generation biofuels as butanol through fermentation processes. Results: This study reports the ability of two laccase preparations from Pleurotus ostreatus to delignify and detoxify milled brewer’s spent grains (BSG). Up to 94% of phenols reduction was achieved. Moreover, thanks to the mild conditions of enzymatic pretreatment, the formation of other inhibitory compounds was avoided allowing to apply the sequential enzymatic pretreatment and hydrolysis process (no filtration and washing steps between the two phases). As expected, the high detoxification and delignification yields achieved by laccase pretreatment resulted in great saccharification. As a fact, no loss of carbohydrates was observed thanks to the novel sequential strategy, and thus the totality of polysaccharides was hydrolysed into fermentable sugars. The enzymatic hydrolysate was fermented to acetone-butanol-ethanol (ABE) by Clostridium acetobutilycum obtaining about 12.6 g/L ABE and 7.83 g/L butanol within 190 h. Conclusions: The applied sequential pretreatment and hydrolysis process resulted to be very effective for the milled BSG, allowing reduction of inhibitory compounds and lignin content with a consequent efficient saccharification. C. acetobutilycum was able to ferment the BSG hydrolysate with ABE yields similar to those obtained by using synthetic media. The proposed strategy reduces the amount of wastewater and the cost of the overall process. Based on the reported results, the potential production of butanol from the fermentation of BSG hydrolysate can be envisaged.Hide Abstract
Increasing atmospheric CO2 and canopy temperature induces anatomical and physiological changes in leaves of the C4 forage species Panicum maximum.
Habermann, E., San Martin, J. A. B., Contin, D. R., Bossan, V. P., Barboza, A., Braga, M. R., Groppo, M. & Martinez, C. A. (2019). PLoS One, 14(2), e0212506.
Changes in leaf anatomy and ultrastructure are associated with physiological performance in the context of plant adaptations to climate change. In this study, we investigated the isolated and combined effects of elevated atmospheric CO2 concentration ([CO2]) up to 600 μmol mol-1 (eC) and elevated temperature (eT) to 2°C more than the ambient canopy temperature on the ultrastructure, leaf anatomy, and physiology of Panicum maximum Jacq. grown under field conditions using combined free-air carbon dioxide enrichment (FACE) and temperature free-air controlled enhancement (T-FACE) systems. Plants grown under eC showed reduced stomatal density, stomatal index, stomatal conductance (gs), and leaf transpiration rate (E), increased soil-water content (SWC) conservation and adaxial epidermis thickness were also observed. The net photosynthesis rate (A) and intrinsic water-use efficiency (iWUE) were enhanced by 25% and 71%, respectively, with a concomitant increase in the size of starch grains in bundle sheath cells. Under air warming, we observed an increase in the thickness of the adaxial cuticle and a decrease in the leaf thickness, size of vascular bundles and bulliform cells, and starch content. Under eCeT, air warming offset the eC effects on SWC and E, and no interactions between [CO2] and temperature for leaf anatomy were observed. Elevated [CO2] exerted more effects on external characteristics, such as the epidermis anatomy and leaf gas exchange, while air warming affected mainly the leaf structure. We conclude that differential anatomical and physiological adjustments contributed to the acclimation of P. maximum growing under elevated [CO2] and air warming, improving the leaf biomass production under these conditions.Hide Abstract
In vitro fermentation of arabinoxylan from oat (Avena sativa L.) by Pekin duck intestinal microbiota.
Tian, D., Xu, X., Peng, Q., Wen, Z., Zhang, Y., Wei, C., Qiao, Y. & Shi, B. (2019). 3 Biotech, 9(2), 54.
Arabinoxylan (AX) is abundant in cereal grains used as feed for ducks. However, the duck intestinal microbes responsible for the degradation of AX are not fully understood. In this study, oat AX was degraded and utilized by different duck intestinal microbiota in vitro. Changes in short-chain fatty acids (SCFAs), branch-chain fatty acids, and the pH resulted from a 72-h AX fermentation in intestinal samples were measured. The addition of AX increased the concentration of isobutyric acid and decreased the concentrations of SCFAs. The pH values decreased significantly in the intestinal samples. Gut microbiota were assessed using high-throughput sequencing of the 16S ribosomal RNA gene, and the results indicated that AX stimulated the growth of Megamonas and Bifidobacterium species, with Megamonas exhibiting the greatest stimulation. Overall, the results suggest that oat AX is utilized by specific bacteria in duck intestines, providing the theoretical basis for the impacts of AX on animal health.Hide Abstract
Higher Chain Length Distribution in Debranched Type‐3 Resistant Starches (RS3) Increases TLR Signaling and Supports Dendritic Cell Cytokine Production.
Lépine, A. F., de Hilster, R. H., Leemhuis, H., Oudhuis, L., Buwalda, P. L. & de Vos, P. (2019). Molecular Nutrition & Food Research, 63(2), 1801007.
Scope: Resistant starches (RSs) are classically considered to elicit health benefits through fermentation. However, it is recently shown that RSs can also support health by direct immune interactions. Therefore, it has been hypothesized that the structural traits of RSs might impact the health benefits associated with their consumption. Methods and results: Effects of crystallinity, molecular weight, and chain length distribution of RSs are determined on immune Toll‐like receptors (TLRs), dendritic cells (DCs), and T‐cell cytokines production. To this end, four type‐3 RSs (RS3) are compared, namely Paselli WFR, JD150, debranched Etenia, and Amylose fraction V, which are extracted from potatoes and enzymatically modified. Dextrose equivalent seems to be the most important feature influencing immune signaling via activation of TLRs. TLR2 and TLR4 are most strongly stimulated. Especially Paselli WFR is a potent activator of multiple receptors. Moreover, the presence of amylose, even to residual levels, enhances DC and T‐cell cytokine responses. Paselli WFR and Amylose fraction V influence T‐cell polarization. Conclusions: It has been shown here that chain length and particularly dextrose equivalent are critical features for immune activation. This knowledge might lead to tailoring and design of immune‐active RS formulations.Hide Abstract
Rheological characterisation of cell walls from wheat flour and endosperm: Effects of diferulate crosslink hydrolysis.
Gartaula, G., Dhital, S., Deshmukh, O., Netzel, G. & Gidley, M. J. (2019). Food Hydrocolloids, 88, 265-271.
The crosslinking of arabinoxylan chains with ferulic acid dimers in wheat endosperm cell walls is hypothesised to limit the swelling and solubilisation of cell wall polysaccharides. In this study, we report the changes in the rheological and chemical properties of cell walls isolated from wheat flour and purified endosperm after treatments intended to cleave the dimers using enzyme (feruloyl esterase) and alkali (NaOH). Treatment with enzyme at the studied amount released less diferulic acid than alkali, and did not release 8-5′ dimers. All treatments markedly altered viscoelastic behaviour. Before enzyme or alkali treatment, cell walls behaved as structured soft solids with elastic modulus (G′) greater than loss modulus (G″) and limited frequency dependence. Both G′ and G″ decreased following enzyme or alkali treatments, and at higher frequencies, the resulting suspension changed behaviour from solid-like to more liquid-like, with G’’ > G′. The alteration of rheological properties and loss of ferulic acid and dimers correlated with the microscopic observation after enzyme/alkali treatment that cell walls lose their structural integrity, as well as releasing more polysaccharide into solution. These results suggest that the breakage of ferulic acid crosslinks can be used as a technique to alter the rheological behaviour of cell wall polysaccharides in wheat flour with consequences for both nutritional as well as processing functionality.Hide Abstract