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商品編號


E-AMGDF-100ML



品牌


Megazyme



公司


Megazyme



公司分類(lèi)


Enzymes



Size

100ML




商品信息

High purity Amyloglucosidase (
Aspergillus niger
) for use in research, biochemical enzyme assays and
in vitro
diagnostic analysis.

EC 3.2.1.3
CAZy Family: GH15
CAS:
9032-08-0

glucan 1,4-alpha-glucosidase; 4-alpha-D-glucan glucohydrolase ?

From
A. niger
. High purity.?Electrophoretically homogeneous.
St
ABI
lised liquid in 50% (v/v) glycerol.

For use in?
Megazyme
Total Starch and Dietary Fiber
?methods.

E-AMGDF-A-100ML specifically to be used with ANKOM
TDF
Dietary Fiber Analyzer.

Specific activity
:
~ 36?U/mg (40
o
C, pH 4.5 on soluble starch);
~ 200 U/mL (40
o
C, pH 4.5,
p
-nitrophenyl β-maltoside);
~ 3,260 U/mL (40
o
C, pH 4.5, soluble starch).

St
ABI
lity
:
> 4 years at 4
o
C.

Data booklets for each pack size are located in the Documentation tab.

View
Megazyme
’s latest Guide for Dietary Fiber Analysis.



Hydrolysis of α-D-glucans and α-D-gluco-oligosaccharides by
cladosporium resinae
glucoamylases.

McCleary, B. V. & Anderson, M. A. (1980).
Carbohydrate Research
, 86(1), 77-96.


Link to Article

Read Abstract

Culture filtrates of
Cladosporium resinae

ATCC
20495 contain a mixture of enzymes able to convert starch and pullulan efficiently into D-glucose. Culture conditions for optimal production of the pullulan-degr
ADI
ng activity have been established. The amylolytic enzyme preparation was fractionated by ion-exchange and molecular-sieve chromatography, and shown to contain α-D-glucosidase, α-amylase, and two glucoamylases. The glucoamylases have been purified to homogeneity and their substrate specificities investigated. One of the glucoamylases (termed P) re
ADI
ly hydrolyses the (1→6)-α-D linkages in pullulan, amylopectin, isomaltose, panose, and 6
3
-α-D-glucosylmaltotriose. Each of the glucoamylases cleaves the (1→6)-α-D linkage in panose much more re
ADI
ly than that in isomaltose.





Measurement of dietary fibre components: the importance of enzyme purity, activity and specificity.

McCleary, B. V. (2001), “
Advanced Dietary Fibre Technology
”, (B. V. McCleary and L. Prosky, Eds.), Blackwell Science, Oxford, U.K., pp. 89-105.


Link to Article

Read Abstract

Interest in dietary fibre is undergoing a dramatic revival, thanks in part to the introduction of new carbohydrates as dietary fibre components. Much emphasis is being placed on determining how much fibre is present in a food. Linking a particular amount of fibre to a specific health benefit is now an important area of research. The term 'dietary fibre' first appeared in 1953, and referred to hemicelluloses, celluloses and lignin (Theandere/tf/.1995). Trowell (1974) recommended this term as a replacement for the no longer acceptable term 'crude fibre'. Burkitt (1995) has likened the interest in dietary fibre to the growth of a river from its first trickle to a mighty torrent He observes that dietary fibre 'was first viewed as merely the less digest
IBL
e constituent of food which exerts a laxative action by irritating the gut', thus acquiring the designation 'roughage' - a term later replaced by 'crude fibre' and ultimately by 'dietary fibre'. Various definitions of dietary fibre have appeared over the years, partly due to the various concepts used in deriving the term (i.e. origin of material, resistance to digestion, fermentation in the colon, etc.), and partly to the difficulties associated with its measurement and labelling (Mongeau
et al
. 1999). The principal components of dietary fibre, as tr
ADI
tionally understood, are non-starch polysaccharides (which in plant fibre are principally hemicelluloses and celluloses), and the non-carbohydrate phenolic components, cutin, suberin and waxes, with which they are associated in nature. In 1976, the definition of dietary fibre was modified to include gums and some pectic substances, based on the resistance to digestion of these components in the upper intestinal tract. For the purposes of labelling, Englyst
et al
. (1987) proposed that dietary fibre be defined as 'non-starch polysaccharides (NSP) in the diet that are not digested by the endogenous secretions of the human digestive tract'. Methods were concurrently developed to specifically measure NSP (Englyst
et al
. 1994).





Dietary fiber and available carbohydrates.

McCleary, B. V. & Rossiter, P. C. (2007). “
Dietary Fiber: An International Perspective for Harmonization of Health Benefits and Energy Values
”, (Dennis T. Gordon and Toshinao Goda, Eds.), AACC International, Inc., pp. 31-59.


Link to Article

Read Abstract

Debate continues on the definition of dietary fiber (DF), methods for measurement of DF, and methods for measurement of the carbohydrates that are re
ADI
ly hydrolyzed and absorbed in the human small intestine. Hen
NEB
erg and Stahmann developed the 'Wende' proximate system for analysis of foods in 1860, and a set of values obtained using this method were published by Atwater and Bryant in 1900. This method is still in use in the USA for the measurement of total carbohydrate. In this procedure, total carbohydrate is measured by difference after deducting the moisture, protein, fat and ash from the total weight. Carbohydrate calculated in this way contains not only sugar and starch, but also the 'unavailable carbohydrate' of DF. However, there are a number of problems with this approach, as the 'by difference' figure includes a number of non-carbohydrate components such as lignin, organic acids, tannins, waxes and some Maillard products. In addition to this error, it combines all of the analytical errors from the other analyses (FAO 1997). A need for information on the carbohydrate composition of foods for diabetics prompted McCance and Lawrence (1929) to attempt to measure carbohydrate composition to gain results that would be of
BIOLOG
ical significance. They divided the carbohydrates in foods into two broad groups, 'available' and 'unavailable'. The available carbohydrates, that is, sugar plus starch, were defined as those that are digested and absorbed by man and are glucogenic. The unavailable carbohydrates were defined as those that are not digested by the endogenous secretions of the human digestive tract. In the mid 1920s, McCance obtained a grant of ?30 per year from the Medical Research Council to analyse raw and cooked fruits and vegetables for total "available carbohydrate"; values needed for calculating diabetic diets.





Measurement of amyloglucosidase using
P
-nitrophenyl β-maltoside as substrate.

McCleary, B. V., Bouhet, F. & Driguez, H. (1991).
Biotechnology Techniques
, 5(4), 255-258.


Link to Article

Read Abstract

An enzyme-linked assay for the measurement of amyloglucosidase in commercial enzyme mixtures and crude culture filtrates is described. A method for the synthesis of the substrate employed,
p
-nitrophenyl β-D-maltoside, is also described. The substrate is used in the presence of saturating levels of β-glucosidase. With a range of
Aspergillus
sp. culture filtrates, an excellent correlation was found for values obtained with this assay and a conventional assay employing maltose as substrate with measurement of released glucose.





Measuring dietary fibre.

McCleary, B. V. (1999).
The World of Ingredients
, 50-53.


Link to Article

Read Abstract

Interest in dietary fibre is undergoing a dramatic revival thanks in part to the introduction of new carbohydrates as dietary fibre components. Much emphasis is being placed on determining how much fibre is present in a food. Linking a particular amount of fibre to a specific health benefit is now an important area of research. Total Dietary Fibre. The term “dietary fibre” first appeared in 1953 and referred to hemicelluloses, celluloses and lignin (1). In 1974, Trowell (2) recommended this term as a replacement for the no longer acceptable term “crude fibre” Burkitt (3) has likened the interest in dietary fibre to the growth of a river from its first trickle to a mighty torrent. He observes that dietary fibre “was viewed as merely the less digest
IBL
e constituent of food which exerts a laxative action by irritating the gut “thus acquiring the designation “roughage” a term which was later replaced by “crude fibre” and ultimately by “dietary fibre” Various definitions of dietary fibre have appeared over the years, partly due the various concepts used in deriving the term (i.e. origin of material, resistance to digestion, fermentation in the colon etc.), and partly to the difficulties associated with its measurement and labelling (4). The principle components of dietary fibre, as tr
ADI
tionally understood, are non-starch polysaccharides, which in plant fibre are principally hemicelluloses and celluloses, and the non-carbohydrate phenolic components, cutin, suberin and waxes with which they are associated in Nature.





Enzyme purity and activity in fibre determinations.

McCleary, B. V. (1999).
Cereal Foods World
, 44(8), 590-596.


Link to Article

Read Abstract

Dietary fiber is mainly composed of plant cell wall polysaccharides such as cellulose, hemicellulose, and pectic substances, but it also includes lignin and other minor components (1). Basically, it covers the polysaccharides that are not hydrolyzed by the endogenous secretions of the human digestive tract (2,3). This definition has served as the target for those developing analytical procedures for the measurement of dietary fiber for quality control and regulatory considerations (4). Most procedures for the measurement of total dietary fiber (TDF), or specific polysaccharide components, either involve some enzyme treatment steps or are mainly enzyme-based. In the development of TDF procedures such as the Prosky method (AOAC International 985.29, AACC 32—05) (5), the Uppsala method (AACC32-25) (6), and the Englyst method (7), the aim was to remove starch and protein through enzyme treatment, and to measure the residue as dietary fiber (after allowing for residual, undigested protein and ash). Dietary fiber was measured either gravimetrically or by chemical or instrumental procedures. Many of the enzyme treatment steps in each of the methods, particularly the prosky (5) and the Uppsala (6) methods are very similar. As a new range of carbohydrates is being introduced as potential dietary fiber components, the original assay procedures will need to be reexamined, and in some cases slightly modified, to ensure accurate and quantitative measurement of these components and of TDF. These “new” dietary fiber components include resistant nondigest
IBL
e oligosaccharides; native and chemically modified polysaccharides of plant and algal origin (galactomannan, chemically modified celluloses, and agars and carrageenans); and resistant starch. To measure these components accurately, the purity, activity, and specificity of the enzymes employed will become much more important. A particular example of this is the mesurement of fructan. This carbohydrate consists of a fraction with a high degree of polymerization (DP) that is precipitated in the standard Prosky method (5,8) and a low DP fraction consequently is not measured (9). Resistant starch poses a particular problem. This component is only partially resistant to degradation by α-amylase, so the level of enzyme used and the incubation conditions (time and temperature) are critical.





Importance of enzyme purity and activity in the measurement of total dietary fibre and dietary fibre components.

McCleary, B. V. (2000).
Journal of AOAC International
, 83(4), 997-1005.


Link to Article

Read Abstract

A study was made of the effect of the activity and purity of enzymes in the assay of total dietary fiber (AOAC Method 985.29) and specific dietary fiber components: resistant starch, fructan, and β-glucan. In the measurement of total dietary fiber content of resistant starch samples, the concentration of α-amylase is critical; however, variations in the level of amyloglucosidase have little effect. Contamination of amyloglucosidase preparations with cellulase can result in significant underestimation of dietary fiber values for samples containing β-glucan. Pure β-glucan and cellulase purified from
Aspergillus niger
amyloglucosidase preparations were used to determine acceptable critical levels of contamination. Sucrose, which interferes with the measurement of inulin and fructooligosaccharides in plant materials and food products, must be removed by hydrolysis of the sucrose to glucose and fructose with a specific enzyme (sucrase) followed by borohydride reduction of the free sugars. Unlike invertase, sucrase has no action on low degree of polymerization (DP) fructooligosaccharides, such as kestose or kestotetraose. Fructan is hydrolyzed to fructose and glucose by the combined action of highly purified
exo
- and
endo
-inulinases, and these sugars are measured by the
p
-hydroxybenzoic acid hydrazide reducing sugar method. Specific measurement of β-glucan in cereal flour and food extracts requires the use of highly purified
endo
-1,3:1,4 β-glucanase and
A. niger
β-glucosidase. β-glucosidase from almonds does not completely hydrolyze mixed linkage β-glucooligosaccharides from barley or oat β-glucan. Contamination of these enzymes with starch, maltosaccharide, or sucrose-hydrolyzing enzymes results in production of free glucose from a source other than β-glucan, and thus an overestimation of β-glucan content. The glucose oxidase and peroxidase used in the glucose determination reagent must be essentially devoid of catalase and α- and β-glucosidase.





Two issues in dietary fiber measurement.

McCleary, B. V. (2001).
Cereal Foods World
, 46, 164-165.


Link to Article

Read Abstract

Enzyme activity and purity of these topics, the easiest to deal with is the importance of enzyme purity and activity. As a scientist actively involved in polysaccharide research over the past 25 years, I have come to appreciate the importance of enzyme purity and specificity in polysaccharide modification and measurement (7). These factors translate directly to dietary fiber (DF) methodology, because the major components of DF are carbohydrate polymers and oligomers. The committee report published in the March issue of Cereal FOODS WORLD refers only to the methodology for measuring enzyme purity and activity (8) that led up the AOAC method 985.29 (2). In this work enzyme purity was gauged by the lack of hydrolysis (i.e., complete recovery) of a particular DF component (e.g. β-glucan, larch galactan or citrus pectin). Enzyme activity was measured by the
ABI
lity to completely hydrolyze representative starch and protein (namely wheat starch and casein). These requirements and restrictions on enzyme purity and activity were adequate at the time the method was initially developed and served as a useful working guide. However, it was recognized that there was a need for more stringent quality definitions and assay procedures for enzymes used in DF measurements.





Dietary fibre analysis.

McCleary, B. V. (2003).
Proceedings of the Nutrition Society
, 62, 3-9.


Link to Article

Read Abstract

The 'gold standard' method for the measurement of total dietary fibre is that of the Association of Official Analytical Chemists (2000; method 985.29). This procedure has been modified to allow measurement of soluble and insoluble dietary fibre, and buffers employed have been improved. However, the recognition of the fact that non-digest
IBL
e oligosaccharides and resistant starch also behave physiologically as dietary fibre has necessitated a re-examination of the definition of dietary fibre, and in turn, a re-evaluation of the dietary fibre methods of the Association of Official Analytical Chemists. With this realisation, the American Association of Cereal Chemists appointed a scientific review committee and charged it with the task of reviewing and, if necessary, updating the definition of dietary fibre. It organised various workshops and accepted comments from interested parties worldwide through an interactive website. More recently, the (US) Food and Nutrition Board of the Institute of Health, National Academy of Sciences, under the oversight of the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, assembled a panel to develop a proposed definition(s) of dietary fibre. Various elements of these definitions were in agreement, but not all. What was clear from both reviews is that there is an immediate need to re-evaluate the methods that are used for dietary fibre measurement and to make appropriate changes where required, and to find new methods to fill gaps. In this presentation, the 'state of the art' in measurement of total dietary fibre and dietary fibre components will be described and discussed, together with suggestions for future research.





Measurement of novel dietary fibres.

McCleary, B. V. & Rossiter, P. (2004).
Journal of AOAC International
, 87(3), 707-717.


Link to Article

Read Abstract

With the recognition that resistant starch (RS) and nondigest
IBL
e oligosaccharides (NDO) act physiologically as dietary fiber (DF), a need has developed for specific and reliable assay procedures for these components. The
ABI
lity of AOAC DF methods to accurately measure RS is dependent on the nature of the RS being analyzed. In general, NDO are not measured at all by AOAC DF Methods 985.29 or 991.43, the one exception being the high molecular weight fraction of fructo-oligosaccharides. Values obtained for RS, in general, are not in good agreement with values obtained by in vitro procedures that more closely imitate the in vivo situation in the human digestive tract. Consequently, specific methods for the accurate measurement of RS and NDO have been developed and validated through interlaboratory studies. In this paper, modifications to AOAC fructan Method 999.03 to allow accurate measurement of enzymically produced fructo-oligosaccharides are described. Suggested modifications to AOAC DF methods to ensure complete removal of fructan and RS, and to simplify pH adjustment before amyloglucosidase addition, are also described.





An integrated procedure for the measurement of total dietary fibre (including resistant starch), non-digest
IBL
e oligosaccharides and available carbohydrates.

McCleary, B. V. (2007).
Analytical and Bioanalytical Chemistry
, 389(1), 291-308.


Link to Article

Read Abstract

A method is described for the measurement of dietary fibre, including resistant starch (RS), non-digest
IBL
e oligosaccharides (NDO) and available carbohydrates. Basically, the sample is incubated with pancreatic α-amylase and amyloglucosidase under conditions very similar to those described in AOAC Official Method 2002.02 (RS). Reaction is terminated and high molecular weight resistant polysaccharides are precipitated from solution with alcohol and recovered by filtration. Recovery of RS (for most RS sources) is in line with published data from ileostomy studies. The aqueous ethanol extract is concentrated, desalted and analysed for NDO by high-performance liquid chromatography by a method similar to that described by Okuma (AOAC Method 2001.03), except that for logistical reasons, D-sorbitol is used as the internal standard in place of glycerol. Available carbohydrates, defined as D-glucose, D-fructose, sucrose, the D-glucose component of lactose, maltodextrins and non-resistant starch, are measured as D-glucose plus D-fructose in the sample after hydrolysis of oligosaccharides with a mixture of sucrase/maltase plus β-galactosidase.





Development and evaluation of an integrated method for the measurement of total dietary fibre.

McCleary, B. V., Mills, C. & Draga, A. (2009).
Quality Assurance and Safety of Crops & Foods
, 1(4), 213–224.


Link to Article

Read Abstract

An integrated total dietary fibre (TDF) method, consistent with the recently accepted CODEX definition of dietary fibre, has been developed. The CODEX Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU) has been deliberating for the past 8 years on a definition for dietary fibre that correctly reflects the current consensus thinking on what should be included in this definition. As this definition was evolving, it became evident to us that neither of the currently available methods for TDF (AOAC Official Methods 985.29 and 991.43), nor a combination of these and other methods, could meet these requirements. Consequently, we developed an integrated TDF procedure, based on the principals of AOAC Official Methods 2002.02, 991.43 and 2001.03, that is compliant with the new CODEX definition. This procedure quantitates high- and low-molecular weight dietary fibres as defined, giving an accurate estimate of resistant starch and non-digest
IBL
e oligosaccharides also referred to as low-molecular weight soluble dietary fibre. In this paper, the method is discussed, modifications to the method to improve simplicity and reproducibility are described, and the results of the first rounds of interlaboratory evaluation are reported.





Determination of total dietary fiber (CODEX definition) by enzymatic-gravimetric method and liquid chromatography: collaborative study.

McCleary, B. V., DeVries, J. W., Rader, J. I., Cohen, G., Prosky, L., Mugford, D. C., Champ, M. & Okuma, K. (2010).
Journal of AOAC International
, 93(1), 221-233.


Link to Article

Read Abstract

A method for the determination of total dietary fiber (TDF), as defined by the CODEX Alimentarius, was validated in foods. Based upon the principles of AOAC
Official Methods
SM
985.29, 991.43, 2001.03, and 2002.02, the method quantitates high- and low-molecular-weight dietary fiber (HMWDF and LMWDF, respectively). In 2007, McCleary described a method of extended enzymatic digestion at 37°C to simulate human intestinal digestion followed by gravimetric isolation and quantitation of HMWDF and the use of LC to quantitate low-molecular-weight soluble dietary fiber (LMWSDF). The method thus quantitates the complete range of dietary fiber components from resistant starch (by utilizing the digestion conditions of AOAC Method 2002.02) to digestion resistant oligosaccharides (by incorporating the deionization and LC procedures of AOAC Method 2001.03). The method was evaluated through an AOAC collaborative study. Eighteen laboratories participated with 16 laboratories returning valid assay data for 16 test portions (eight blind duplicates) consisting of samples with a range of tr
ADI
tional dietary fiber, resistant starch, and nondigest
IBL
e oligosaccharides. The dietary fiber content of the eight test pairs ranged from 11.57 to 47.83. Digestion of samples under the conditions of AOAC Method 2002.02 followed by the isolation and gravimetric procedures of AOAC Methods 985.29 and 991.43 results in quantitation of HMWDF. The filtrate from the quantitation of HMWDF is concentrated, deionized, concentrated again, and analyzed by LC to determine the LMWSDF, i.e., all nondigest
IBL
e oligosaccharides of degree of polymerization 3. TDF is calculated as the sum of HMWDF and LMWSDF. Repeat
ABI
lity standard deviations (S
r
) ranged from 0.41 to 1.43, and reproducibility standard deviations (S
R
) ranged from 1.18 to 5.44. These results are comparable to other official dietary fiber methods, and the method is recommended for adoption as Official First Action.





Determination of insoluble, soluble, and total dietary fiber (codex definition) by enzymatic-gravimetric method and liquid chromatography: Collaborative Study.

McCleary, B. V., DeVries, J. W., Rader, J. I., Cohen, G., Prosky, P., Mugford, D. C., Champ, M. & Okuma, K. (2012).
Journal of AOAC International
, 95(3), 824-844.


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A method for the determination of insoluble (IDF), soluble (SDF), and total dietary fiber (TDF), as defined by the CODEX Alimentarius, was validated in foods. Based upon the principles of AOAC
Official Methods
SM
985.29, 991.43, 2001.03, and 2002.02, the method quantitates water-insoluble and water-soluble dietary fiber. This method extends the cap
ABI
lities of the previously adopted AOAC
Official Method
2009.01, Total Dietary Fiber in Foods, Enzymatic-Gravimetric-Liquid Chromatographic Method, applicable to plant material, foods, and food ingredients consistent with CODEX Definition 2009, including naturally occurring, isolated, modified, and synthetic polymers meeting that definition. The method was evaluated through an AOAC/AACC collaborative study. Twenty-two laboratories participated, with 19 laboratories returning valid assay data for 16 test portions (eight blind duplicates) consisting of samples with a range of tr
ADI
tional dietary fiber, resistant starch, and nondigest
IBL
e oligosaccharides. The dietary fiber content of the eight test pairs ranged from 10.45 to 29.90%. Digestion of samples under the conditions of AOAC 2002.02 followed by the isolation, fractionation, and gravimetric procedures of AOAC 985.29 (and its extensions 991.42 and 993.19) and 991.43 results in quantitation of IDF and soluble dietary fiber that precipitates (SDFP). The filtrate from the quantitation of water-alcohol-insoluble dietary fiber is concentrated, deionized, concentrated again, and analyzed by LC to determine the SDF that remains soluble (SDFS), i.e., all dietary fiber polymers of degree of polymerization = 3 and higher, consisting primarily, but not exclusively, of oligosaccharides. SDF is calculated as the sum of SDFP and SDFS. TDF is calculated as the sum of IDF and SDF. The within-laboratory vari
ABI
lity, repeat
ABI
lity SD (S
r
), for IDF ranged from 0.13 to 0.71, and the between-laboratory vari
ABI
lity, reproducibility SD (s
R
), for IDF ranged from 0.42 to 2.24. The within-laboratory vari
ABI
lity s
r
for SDF ranged from 0.28 to 1.03, and the between-laboratory vari
ABI
lity sR for SDF ranged from 0.85 to 1.66. The within-laboratory vari
ABI
lity sr for TDF ranged from 0.47 to 1.41, and the between-laboratory vari
ABI
lity s
R
for TDF ranged from 0.95 to 3.14. This is comparable to other official and approved dietary fiber methods, and the method is recommended for adoption as Official First Action.





Measurement of total dietary fiber using AOAC method 2009.01 (AACC International approved method 32-45.01): Evaluation and updates.

McCleary, B. V., Sloane, N., Draga, A. & Lazewska, I. (2013).
Cereal Chemistry
, 90(4), 396-414.


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Read Abstract

The Codex Committee on Methods of Analysis and Sampling recently recommended 14 methods for measurement of dietary fiber, eight of these being type I methods. Of these type I methods, AACC International Approved Method 32-45.01 (AOAC method 2009.01) is the only procedure that measures all of the dietary fiber components as defined by Codex Alimentarius. Other methods such as the Prosky method (AACCI Approved Method 32-05.01) give similar analytical data for the high-molecular-weight dietary fiber contents of food and vegetable products low in resistant starch. In the current work, AACCI Approved Method 32-45.01 has been modified to allow accurate measurement of samples high in particular fructooligosaccharides: for example, fructotriose, which, in the HPLC system used, chromatographs at the same point as disaccharides, meaning that it is currently not included in the measurement. Incubation of the resistant oligosaccharides fraction with sucrase/β-galactosidase removes disaccharides that interfere with the quantitation of this fraction. The dietary fiber value for resistant starch type 4 (RS
4
), varies significantly with different analytical methods, with much lower values being obtained with AACCI Approved Method 32-45.01 than with 32-05.01. This difference results from the greater susceptibility of RS
4
to hydrolysis by pancreatic α-amylase than by bacterial α-amylase, and also a greater susceptibility to hydrolysis at lower temperatures. On hydrolysis of samples high in starch in the assay format of AACCI Approved Method 32-45.01 (AOAC method 2009.01), resistant maltodextrins are produced. The major component is a heptasaccharide that is highly resistant to hydrolysis by most of the starch-degr
ADI
ng enzymes studied. However, it is hydrolyzed by the maltase/amyloglucosidase/isomaltase enzyme complex present in the brush border lining of the small intestine. As a consequence, AOAC methods 2009.01 and 2011.25 (AACCI Approved Methods 32-45.01 and 32-50.01, respectively) must be updated to include an additional incubation with amyloglucosidase to remove these oligosaccharides.





Modification to AOAC Official Methods 2009.01 and 2011.25 to allow for minor overestimation of low molecular weight soluble dietary fiber in samples containing starch.

McCleary, B. V. (2014).
Journal of AOAC International
, 97(3), 896-901.


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AOAC Official Methods 2009.01 and 2011.25 have been modified to allow removal of resistant maltodextrins produced on hydrolysis of various starches by the combination of pancreatic α-amylase and amyloglucosidase (AMG) used in these assay procedures. The major resistant maltodextrin, 6
3
,6
5
-di-α-D-glucosyl maltopentaose, is highly resistant to hydrolysis by microbial α-glucosidases, isoamylase, pullulanase, pancreatic, bacterial and fungal α-amylase and AMG. However, this oligosaccharide is hydrolyzed by the mucosal α-glucosidase complex of the pig small intestine (which is similar to the human small intestine), and thus must be removed in the analytical procedure. Hydrolysis of these oligosaccharides has been by incubation with a high concentration of a purified AMG at 60°C. This incubation results in no hydrolysis or loss of other resistant oligosaccharides such as FOS, GOS, XOS, resistant maltodextrins (e.g., Fibersol 2) or polydextrose. The effect of this additional incubation with AMG on the measured level of low molecular weight soluble dietary fiber (SDFS) and of total dietary fiber in a broad range of samples is reported. Results from this study demonstrate that the proposed modification can be used with confidence in the measurement of dietary fiber.





Physical, microscopic and chemical characterisation of industrial rye and wheat brans from the Nordic countries.

Kamal-Eldin, A., L?rke, H. N., Knudsen, K. E. B., Lampi, A. M., Piironen, V., Adlercreutz, H., Katina, K., Poutanen, K. & Aman, P. (2009).
Food & nutrition research
, 53.


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Background:
Epidemiological studies show inverse relationship between intake of wholegrain cereals and several chronic diseases. Components and mechanisms behind poss
IBL
e protective effects of wholegrain cereals are poorly understood.
Objective:
To characterise commercial rye bran preparations, compared to wheat bran, regarding structure and content of nutrients as well as a number of presumably bioactive compounds.
Design:
Six different rye brans from Sweden, Denmark and Finland were analysed and compared with two wheat brans regarding colour, particle size distribution, microscopic structures and chemical composition including proximal components, vitamins, minerals and bioactive compounds.
Results:
Rye brans were generally greener in colour and smaller in particle size than wheat brans. The rye brans varied considerably in their starch content (13.2–;28.3%), which reflected variable inclusion of the starchy endosperm. Although rye and wheat brans contained comparable levels of total dietary fibre, they differed in the relative proportions of fibre components (i.e. ar
ABI
noxylan, β-glucan, cellulose, fructan and Klason lignin). Generally, rye brans contained less cellulose and more β-glucan and fructan than wheat brans. Within small variations, the rye and wheat brans were comparable regarding the contents of tocopherols/tocotrienols, total folate, sterols/stanols, phenolic acids and lignans. Rye bran had less glycine betaine and more alkylresorcinols than wheat brans.
Conclusions:
The observed variation in the chemical composition of industrially produced rye brans calls for the need of standardisation of this commodity, especially when used as a functional ingredient in foods.





Relationship of grain fructan content to degree of polymerisation in different barleys.

Nemeth, C., Andersson, A. A. M., Andersson, R., Mangelsen, E., Sun, C. & ?man, P. (2014).
Food and Nutrition Sciences
, 5, 581-589.


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Fructans are important in the survival of plants and also valuable for humans as potentially health promoting food ingredients. In this study fructan content and composition were determined in grains of 20 barley breeding lines and cultivars with a wide variation in chemical composition, morphology and country of origin, grown at one site in Chile. There was significant genotypic variation in grain fructan content ranging from 0.9% to 4.2% of grain dry weight. Fructan degree of polymerisation (DP) was analysed using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Changes in the distribution of different chain lengths and the pattern of structures of fructan were detected with increasing amount of fructan in the different barleys. A positive correlation was found between fructan content and the relative amount of long chain fructan (DP > 9) (r = 0.54, p = 0.021). Our results provide a basis for selecting promising barley lines and cultivars for further research on fructan in barley breeding with the aim to produce healthy food products.





How does the preparation of rye porridge affect molecular weight distribution of extractable dietary fibers?

Rakha, A., ?man, P. & Andersson, R. (2011).
International journal of molecular sciences
, 12(5), 3381-3393.


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Extractable dietary fiber (DF) plays an important role in nutrition. This study on porridge making with whole grain rye investigated the effect of rest time of flour slurries at room temperature before cooking and amount of flour and salt in the recipe on the content of DF components and molecular weight distribution of extractable fructan, mixed linkage (1→3)(1→4)-β-D-glucan (β-glucan) and ar
ABI
noxylan (AX) in the porridge. The content of total DF was increased (from about 20% to 23% of dry matter) during porridge making due to formation of insoluble resistant starch. A small but significant increase in the extract
ABI
lity of β-glucan (
P
= 0.016) and AX (
P
= 0.002) due to rest time was also noted. The molecular weight of extractable fructan and AX remained stable during porridge making. However, incubation of the rye flour slurries at increased temperature resulted in a significant decrease in extractable AX molecular weight. The molecular weight of extractable β-glucan decreased greatly during a rest time before cooking, most likely by the action of endogenous enzymes. The amount of salt and flour used in the recipe had small but significant effects on the molecular weight of β-glucan. These results show that whole grain rye porridge made without a rest time before cooking contains extractable DF components maintaining high molecular weights. High molecular weight is most likely of nutritional importance.





Baselines representing blood glucose clearance improve in vitro prediction of the glycaemic impact of customarily consumed food quantities.

Monro, J. A., Mishra, S. & Venn, B. (2010).
British Journal of Nutrition
, 103(2), 295-305.


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Glycaemic responses to foods reflect the balance between glucose loading into, and its clearance from, the blood. Current
in vitro
methods for glycaemic analysis do not take into account the key role of glucose disposal. The present study aimed to develop a food intake-sensitive method for measuring the glycaemic impact of food quantities usually consumed, as the difference between release of glucose equivalents (GGE) from food during
in vitro
digestion and a corresponding estimate of clearance of them from the blood. Five foods – white bread, fruit bread, muesli bar, mashed potato and chickpeas – were consumed on three occasions by twenty volunteers to provide blood glucose response (BGR) curves. GGE release during
in vitro
digestion of the foods was also plotted. Glucose disposal rates estimated from downward slopes of the BGR curves allowed GGE dose-dependent cumulative glucose disposal to be calculated. By subtracting cumulative glucose disposal from cumulative
in vitro
GGE release, accuracy in predicting the
in vitro
glycaemic effect from
in vitro
GGE values was greatly improved. GGE
in vivo
= 0·99GGE
in vitro
+0·75 (
R
2
0·88). Fur
Thermo
re, the difference between the curves of cumulative GGE release and disposal closely mimicked
in vivo
incremental BGR curves. We conclude that valid measurement of the glycaemic impact of foods may be obtained
in vitro
, and expressed as grams of glucose equivalents per food quantity, by taking account not only of GGE release from food during
in vitro
digestion, but also of blood glucose clearance in response to the food quantity.





Effect of processing on slowly digest
IBL
e starch and resistant starch in potato.

Mishra, S., Monro, J. & Hedderley, D. (2008).
Starch‐St?rke
, 60(9), 500-507.


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The effect of a number of laboratory-scale pretreatments on the proportions of rapidly digested (RDS), slowly digested (SDS) and resistant starch (RS) in raw and cooked potato has been examined using an
in vitro
digestion procedure. Potatoes of the variety Frisia were prepared in three states: raw, cooked, and cooked followed by a cold treatment (4°C, two days). Each preparation was then subjected in triplicate to freeze-drying, coarsely mincing, pasting, freezing, dry-milling after freeze-drying, in 22 different combinations, before digesting. In raw potato, very little RDS and SDS (<5% total="" starch="" (ts))="" were="" present,="" and="" the="" mechanical="" treatments="" of="" the="" potato="" did="" not="" affect="" the="" amounts="" of="" rds="" and="" sds.="" cooking="" resulted="" in="" an="" almost="" complete="" conversion="" to="" rds="" (="">95% TS) in freshly-cooked potato, but after post-cooking cold treatment much of the RDS transformed to SDS, which reached a maximum of about 45% TS. SDS formation was independent of the degree of tissue disruption after cooking, and was generally associated with formation of RS, however, freezing after cooking allowed SDS formation without prolonged cold treatment and with very little associated RS (SDS 35% and RS 4% of TS). Freeze-drying caused an increase in RS in most treatments of the cooked potatoes. The observed effects provided guidance for sample handling in potato research, but also suggested several approaches to the enrichment of SDS and/or RS, with a concurrent reduction in RDS, that could be used to improve the nutritional profile of potato products by decreasing RDS (lowered glycaemic impact), and increasing SDS (more sustained energy avail
ABI
lity) and RS (prebiotic benefits). 5%>





Investigation of digestibility in vitro and physicochemical properties of A- and B- type starch from soft and hard wheat flour.

Liu, Q., Gu, Z., Donner, E., Tetlow, I. & Emes, M. (2007).
Cereal Chemistry
, 84(1), 15-21.


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In this study, the functional properties of A- and B-type wheat starch granules from two commercial wheat flours were investigated for digestibility in vitro, chemical composition (e.g., amylose, protein, and ash content), gelatinization, retrogradation, and pasting properties. The branch chain length and chain length distribution of these A- and B-type wheat starch granules were also determined using high-performance anion exchange chromatography (HPAEC). Wheat starches with different granular sizes not only had different degrees of enzymatic hydrolysis and thermal and pasting properties, but also different molecular characteristics. Different amylose content, protein content, and branch chain length of amylopectin in A- and B-type wheat starch granules could also be the major factors besides granular size for different digestibility and other functional properties of starch. The data indicate that different wheat cultivars with different proportion of A- and B-type granular starch could result in different digestibility in wheat products.





Determination of resistant short-chain carbohydrates (non-digest
IBL
e oligosaccharides) using gas–liquid chromatography.

Quigley, M. E., Hudson, G. J. & Englyst, H. N. (1999).
Food Chemistry
, 65(3), 381-390.


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We have proposed the term short-chain carbohydrates (SCC) for those species, other than the free sugars, that are soluble in 80% ethanol under well-defined conditions. We describe a technique for the measurement of resistant SCC (RSCC), which are not suscept
IBL
e to pancreatic amylase or the brush border enzymes and therefore sometimes termed non-digest
IBL
e oligosaccharides. In the procedure, alpha-glucans (starch and maltodextrins) are hydrolysed enzymatically to glucose and the non-starch polysaccharides (NSP) are precipitated in ethanol. Fructans are hydrolysed enzymatically and the monosaccharide constituents are reduced to acid-stable alditol derivatives before the remaining RSCC are hydrolysed with sulphuric acid. All the constituent sugars are measured as alditol acetate derivatives by gas–liquid chromatography. The protocol allows both the measurement of total RSCC and a separate, specific measurement of fructans.





The physicochemical properties and in vitro digestibility of selected cereals, tubers and legumes grown in China.

Liu, Q., Donner, E., Yin, Y., Huang, R. L. & Fan, M. Z. (2006).
Food Chemistry
, 99(3), 470-477.


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Digestibility, gelatinization, retrogradation and pasting properties of starch in various cereal, tuber and legume flours were determined. Rapidly and slowly digest
IBL
e starch and resistant starch were present in 11 selected flours. In general, cereal starches were more digest
IBL
e than legume starches and tuber starches contained a high amount of resistant starch. Thermal and rheological properties of flours were different depending on the crop source.





Development and physicochemical characterization of new resistant citrate starch from different corn starches.

Xie, X. S. & Liu, Q. (2004).
Starch‐St?rke
, 56(8), 364-370.


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Resistant starch has drawn broad interest for both potential health benefits and functional properties. In this study, a technology was developed to increase resistant starch content of corn starch using esterification with citric acid at elevated temperature. Waxy corn, normal corn and high-amylose corn starches were used as model starches. Citric acid (40% of starch dry weight) was reacted with corn starch at different temperatures (120–150°C) for different reaction times (3–9 h). The effect of reaction conditions on resistant starch content in the citrate corn starch was investigated. When conducting the reaction at 140°C for 7 h, the highest resistant starch content was found in waxy corn citrate starch (87.5%) with the highest degree of substitution (DS, 0.16) of all starches. High-amylose corn starch had 86.4% resistant starch content and 0.14 DS, and normal corn starch had 78.8% resistant starch and 0.12 DS. The physicochemical properties of these citrate starches were characterized using various analytical techniques. In the presence of excess water upon heating, citrate starch made from waxy corn starch had no peak in the DSC
Thermo
gram, and small peaks were found for normal corn starch (0.4 J/g) and Hylon VII starch (3.0 J/g) in the
Thermo
grams. This indicates that citrate substitution changes granule properties. There are no retrogradation peaks in the
Thermo
grams when starch was reheated after 2 weeks storage at 5°C. All the citrate starches showed no peaks in RVA pasting curves, indicating citrate substitution changes the pasting properties of corn starch as well. Moreover, citrate starch from waxy corn is more thermally stable than the other citrate starches.





Determination of “Net Carbohydrates” using high-performance anion exchange chromatography.

Lilla, Z., Sullivan, D., Ellefson, W., Welton, K. & Crowley, R. (2005).
Journal of AOAC International
, 88(3), 714-719.


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For labeling purposes, the carbohydrate content of foods has traditionally been determined by difference. This value includes sugars, starches, fiber, dextrins, sugar alcohols, polydextrose, and various other organic compounds. In some cases, the current method may lack sufficient specificity, precision, and accuracy. These are subsequently quantitated by high performance anion exchange chromatography with pulsed amperometric detection and expressed as total nonfiber saccharides or percent “net carbohydrates.” In this research, a new method was developed to address this need. The method consists of enzyme digestions to convert starches, dextrins, sugars, and polysaccharides to their respective monosaccharide components. These are subsequently quantified by high-performance anion exchange chromatography with pulsed amperometric detector and expressed as total nonfiber saccharides or percent “net carbohydrates.” Hydrolyzed end products of various novel fibers and similar carbohydrates have been evaluated to ensure that they do not register as false positives in the new test method. The data generated using the “net carbohydrate” method were, in many cases, significantly different than the values produced using the traditional methodology. The recoveries obtained in a fortified drink matrix ranged from 94.9 to 105%. The coefficient of variation was 3.3%.





Cereal Byproducts have Prebiotic Potential in Mice Fed a High-fat Diet.

Berger, K., Falck, P., Linninge, C.,Nilsson, U., Axling, U., Grey, C., St?lbrand, H., Karlsson, E. N., Nyman, M., Holm, C. & Adlercreutz, P. (2014).
Journal of Agricultural and Food Chemistry
, 62(32), 8169-8178.


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Barley husks, rye bran, and a fiber residue from oat milk production were processed by heat pretreatment, various separation steps, and treatment with an endoxylanase in order to improve the prebiotic potential of these cereal byproducts. Metabolic functions were intended to improve along with improved microbial activity. The products obtained were included in a high-fat mouse diet so that all diets contained 5% dietary fiber. In addition, high-fat and low-fat controls as well as partially hydrolyzed guar gum were included in the study. The soluble fiber product obtained from rye bran caused a significant increase in the bifidobacteria (log copies of 16S rRNA genes; median (25–75 percentile): 6.38 (6.04–6.66) and 7.47 (7.30–7.74), respectively;
p
< 0.001)="" in="" parallel="" with="" a="" tendency="" of="" increased="" production="" of="" propionic="" acid="" and="" indications="" of="" improved="" metabolic="" function="" compared="" with="" high-fat="" fed="" control="" mice.="" the="" oat-derived="" product="" caused="" an="" increase="" in="" the="" pool="" of="" cecal="" propionic="" (from="" 0.62="" ±="" 0.12="" to="" 0.94="" ±="" 0.08)="" and="" butyric="" acid="" (from="" 0.38="" ±="" 0.04="" to="" 0.60="" ±="" 0.04)="" compared="" with="" the="" high-fat="" control,="" and="" it="" caused="" a="" significant="" increase="" in="" lactobacilli="" (log="" copies="" of="" 16s="" rrna="" genes;="" median="" (25–75="" percentile):="" 6.83="" (6.65–7.53)="" and="" 8.04="" (7.86–8.33),="" respectively;="">
p
< 0.01)="" in="" the="" cecal="" mucosa.="" however,="" no="" changes="" in="" measured="" metabolic="" parameters="" were="" observed="" by="" either="" oat="" or="" barley="" products.="">





Extraction of β-glucan from oats for soluble dietary fiber quality analysis.

Doehlert, D. C., Simsek, S. & McMullen, M. S. (2012).
Cereal Chemistry
, 89(5), 230-236.


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Extraction protocols for β-glucan from oat flour were tested to determine optimal conditions for β-glucan quality testing, which included extract
ABI
lity and molecular weight. We found mass yields of β-glucan were constant at all temperatures, pH values, and flour-to-water ratios, as long as sufficient time and enough repeat extractions were performed and no hydrolytic enzymes were present. Extracts contained about 30–60% β-glucan, with lower proportions associated with higher extraction temperatures in which more starch and protein were extracted. All commercial starch hydrolytic enzymes tested, even those that are considered homogenous, degraded β-glucan apparent molecular weight as evaluated by size-exclusion chromatography. Higher concentration β-glucan solutions could be prepared by controlling the flour-to-water ratio in extractions. Eight grams of flour per 50 mL of water generated the highest native β-glucan concentrations. Routine extractions contained 2 g of enzyme-inactivated flour in 50 mL of water with 5m
M
sodium azide (as an antimicrobial), which were stirred overnight, centrifuged, and the supernatant boiled for 10 min. The polymer extracted had a molecular weight of about 2 million and was stable at room temperature for at least a month.





Effect of dietary starch source on growth performances, digestibility and quality traits of







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