FSA – An evaluation of the methodological approaches for ... Carbohydrates Chemistry • Quality ... An evaluation of the methodological approaches for the determination of different carbohydrate fractions in foods
Post on 10-Mar-2018
Embed Size (px)
FSA An evaluation of the methodological approaches for the determination of different carbohydrate fractions in foods
16 November 2009
Established over 150 years ago
UK government laboratory
Privatised in 1996
Acquisitions include: Promochem Group
QM / Aquacheck
Central Services & Support
Research & Technology
Reference material distribution
Cell lines and microbiology products
Reference material production
Proficiency testing schemes
Outsourcing of in-house reference standards groups
Analytical quality training courses
Life & Food Sciences
Food quality & safety
Food chain surveillance
UK designated NMI for chemistry and biology
Metrology and analytical technology
Molecular biology, mass spectrometry, cell and protein R&D assets
POET Operational Excellence
British Pharmacopoeia Lab
Occupational drug testing
Fluids, marks, stains
Computers & phones
Bromsgrove St Neots
LGC Life & Food Sciences
Edinburgh, Exeter & Runcorn
>2.5m brainstems tested
400 test varieties
35,000 test p.a.
Drug detection in food & animal products
UK and non UK government
Quality, composition, description R&D- CNS
Consumer driven issues
Government Chemist programme
Department of Health
Research management services
Testing consumer products
Specialists in nitrosamines & organo-tin analyses
DNA / Genetic Analysis Services
Next Gen sequencing
24/7 response Health & Safety Water quality
Food ChemistryFood, Feed & Fertilisers
An evaluation of the methodological approaches for the determination of different carbohydrate fractions in foods.
Food Standards Agency 2009.
To review and evaluate options available to analysts determining the various carbohydrate fractions that occur naturally and that have been added to foods.
What are carbohydrates?
Sugars: glucose, fructose, sucrose, maltose, galactose
Starch: Various types, resistant starch, modified starch
Partially hydrolysed starch products : Maltodextrins, glucose syrups,
Other oligosaccharides: FOS, GOS, XOS, Polydextrose etc
Dietary fibre: NSP, cellulose, hemi-cellulose, pectins, gums and
mucilages, algal polysaccharides, lignin
Carbohydrates: Available, non-available, glyceamic, non-glyceamic
Sugars, reducing sugars, non-reducing sugars, total sugars, free sugars, added sugars, refined sugars, extrinsic sugars, intrinsic sugars, milk sugars, monosaccharides, disaccharides, oligosaccharides
Partially hydrolysed starch, maltodextrin, glucose syrup, fructose syrup.
Starch, slowly digestible starch, rapidly digestible starch, resistant starch, modified starch, polysaccharides....
Dietary fibre, Non-starch polysaccharides (NSP), insoluble fibre, soluble fibre, cellulose, hemicellulose, No agreed definition.
Carbohydrates by difference
100% - %protein - %fat - %moisture - %minerals
No information about different carbohydrate types
Subject to uncertainty in the other determinations.
Specific methods preferred.
Methods for sugars
Gravimetry: e.g.Munson & Walker (Total reducing sugars)
Titration: e.g. Lane & Eynon (Total reducing sugars)
Colorimetry: Anthrone method, Phenol-sulphuric (reducing and non-reducing sugars)
Enzymatic Assays (e.g. hexakinase / glucose oxidase for glucose)
HPLC, GLC, HPAEC,
Methods for starch
Physical and chemical methods Iodine titration, polarimetry- Ewers method
Acid hydrolysis methods
Enzymatic methods Hydrolysis of starch (& other -glucans) with amylase and
amyloglucosidase to form glucose.
AOAC, AACC, Englyst, Megazyme, Other
Methods for fibre
Many methods proposed in the last two decades:
Crude fibre, acid detergent fibre, neutral detergent fibre, Uppsala method, Theander method, AOAC methods, Englyst (NSP) methods.
AOAC (985.29, 991.43) most commonly used
Englyst (NSP) in UK for claims but AOAC also used for labelling.
Newer methods for resistant starch, oligosaccharides,
polydextrose, resistant maltodextrins, fructans
Codex definition of dietary fibre
Dietary fibre means carbohydrate polymers1 with ten or more monomeric units 2, which are not hydrolysedby the endogenous enzymes in the small intestine of humans and belong to the following categories:
edible carbohydrate polymers naturally occurring in the food as consumed,
carbohydrate polymers, which have been obtained from food raw material by physical, enzymatic or chemical means and which have been shown to have a physiological effect of benefit to health as demonstrated by generally accepted scientific evidence to competent authorities,
synthetic carbohydrate polymers which have been shown to have a physiological effect of benefit to health as demonstrated by generally accepted scientific evidence to competent authorities.
Methods of Analysis for Dietary Fibre To be agreed.
1 When derived from a plant origin, dietary fibre may include fractions of lignin and/or other compounds when associated with polysaccharides in the plant cell walls and if these compounds are quantified by the AOAC gravimetric analytical method for dietary fibre analysis : Fractions of lignin and the other compounds (proteic fractions, phenolic compounds, waxes, saponins, phytates, cutin, phytosterols, etc.) intimately "associated" with plant polysaccharides are often extracted with the polysaccharides in the AOAC 991.43 method. These substances are included in the definition of fibre insofar as they are actually associated with the poly- or oligo-saccharidic fraction of fibre. However, when extracted or even re-introduced into a food containing non digestible polysaccharides, they cannot be defined as dietary fibre. When combined with polysaccharides, these associated substances may provide additional beneficial effects (pending adoption of Section on Methods of Analysis and Sampling).
2 Decision on whether to include carbohydrates from 3 to 9 monomeric units should be left to national authorities.
EC definition (Directive 2008/100/EEC) includes carbohydrates with >3 monomeric units with similar categories and includes the concepts of indigestibility and physiological effect.
Background to the project
For nutrition labelling, claims and enforcement purposes, there is a need to accurately quantify the presence of a range of carbohydrate components in foods.
Information should be of nutritional relevance, should assist consumers with informed dietary selection and should not be open to misinterpretation.
A large number of AOAC and other methods for the determination of various fractions of starch, oligosaccharides and dietary fibre are available.
Industry and enforcement analysts face difficult analytical choices if they wish to produce data that will withstand critical review.
Increasing knowledge of the physiological effects of carbohydrate components, the complexity of carbohydrate products commercially available and the ever incr