School of Food and Nutritional Sciences University College Cork Ireland Overview on gluten free cereal research at UCC

Transcription

1 School of Food and Nutritional Sciences University College Cork Ireland Overview on gluten free cereal research at UCC Professor Elke Arendt School of Food and Nutritional Sciences University College Cork Ireland Coeliac Disease What is coeliac disease? Autoimmune disease Intolerance to gluten Changes to the lining of the upper part of intestine Malabsorption Symptoms: Infancy (0-2 years) Diarrhoea, Abdominal distension, Failure to thrive, Anorexia and Psychomotor impairment Childhood Diarrhoea or constipation Anaemia Loss of appetite Adulthood Diarrhoea or constipation Anaemia Aphthous ulcers, sore tongue and mouth

2 Disease mechanism Epithelial cells renewed every 4 days Enzyme production for digestion Gluten triggers immunological response in small intestine destroys absorptive epithelial cells Possible causes Genetic predisposition Environmental factors Immunological based inflammation Left - Normal intestinal mucosa Right - Mucosa involved by celiac sprue CD is a multi-organ autoimmune disease caused by gluten intolerance adapted from Rewers 2005

3 Epidemiology of coeliac disease 1 to 2 % of the world population suffers from celiac disease. Most common food intolerance Iceberg model depicting prevalence of coeliac disease from Feighery (1999) Prevalence of coeliac disease based on clinical diagnosis or screening data (from Fasano and Catassi, 2001) Geographic area Prevalence on clinical diagnosis Prevalence on screening data Denmark 1:10,000 1:500 Finland 1:1000 1:130 Germany 1:2300 1:500 Italy 1:1000 1:184 Netherlands 1:4500 1:198 Norway 1:675 1:250 Sweden 1:330 1:190 United Kingdom 1:300 1:112 United States 1:10,000 1:111 Worldwide average 1:3345 1:266 Treatment Gluten free diet? Wheat Barley Rye Oats

4 Cereals Allowed: GF Cereals and Pseudocereals Oryzoidae Rice Panicoideae zea mays Maize Sorghum bicolor Sorghum Eragrostis tef Teff Eleusin coracana Finger millet Pennisetum glaucum Perl Millet Setaria Italica Italien Millet Fagopyrum esculentum Buckwheat Amaranthus cruentus Amaranth Chenopodium quinoa Quinoa Pseudocereals Consumers benefitting from a gluten free diet Coeliac Disease patients ( 1 to 2 % of the population) Gluten sensitivity (10 to 20 %) Wheat protein allergies (very small %) Autism Irritable Bowel Syndrome and Crones Disease (approx. 20 %) Skin-disorders Life style choice Special diets Relations from above patients 9 out of 10 consumers buying GF-foods are not Coeliac patients

5 Gluten free Market study Free-from market: 300% growth since 2000 Growth rate of 25% per year Only 1 out of 10 consumers buying GF-products are coeliac patients Marketing study UCC 100 bread products from 15 countries Nutritional Information Volume Texture Sensory evaluation Price Dry, crumbly mouth feel and off-flavor Lack of Nutrients, high in fat Rapid staling (mostly starch based) Expensive Long shelf life Nutritional Composition of GF Breads Gluten free white bread Wheat bread Calories 196 kcal 311 kcal 219 kcal Fat 1.7 % 15.6 % 1.4 % Protein 1.1 % 6.6 % 8.7 % Carbohydrates 35.0 % 62.7 % 43.0 % Fibre 0.1 % 8.3 % 2.8 %

6 Fibre supplements in commercial breads wheat flour + water Bread-making GF flour + water Wheat vs. Gluten-free mixing mixing proofing CLSM of dough/batter proofing baking baking CLSM of bread crumbs

7 Gluten Gluten Gliadin Glutenin Endosperm Function Water-binding - helps starch gelatinisation during baking Visco-elastic properties gas retention during fermentation Gluten associated proteases bread flavour Cereals Pseudo-cereals Hydrocolloids Dough improvers Gluten-free flours Starches Functional ingredients High fibre ingredients New Generation Gluten-free bread development Novel processing approaches Enzymes Lactic acid bacteria High pressure

8 School of Food and Nutritional Sciences University College Cork Ireland Gluten free cereals and their characterisation Gluten free cereals Oryzoidae Rice Panicoideae zea mays Maize Sorghum bicolor Sorghum Eragrostis tef Teff Eleusin coracana Finger millet Pennisetum glaucum Proso Millet Avena sativa L. Oats Fagopyrum esculentum Buckwheat Amaranthus cruentus Amaranth Chenopodium quinoa Quinoa Pseudocereals

9 Potential nutritional deficiencies On diagnosis On GF diet On long-term GF diet Protein/calorie Fibre Fe, Zn, Cu, Mn Vit D, Vit K Ca, Mg Folate, B 12 Thiamin Niacin Pyridoxine Riboflavin Se, Carnitine Fibre Fe, Zn VitD Ca, Mg Folate, B 12 Niacin Riboflavin Fibre Folate, B 12 Niacin Pyridoxine based on data provided by Kennedy et al. Evaluation of technological and nutritional properties of gluten-free raw materials and end products Loaf volume Moisture Water activity Crumb texture Crumb structure Staling Microbial shelf life Bake loss In vitro digestibility Sensory evaluation Ultrastructure Protein Aminoacids Fat Starch Fibre Folate Minerals Polyphenols Product quality Nutrition Technology Rheology Bioanalyser Rapid Viscoanalyser Enzyme activities Rheofermentometer Particle size Waterholdingcapacity Differential scanning calorimetry

10 Whole wheat 1% 4% Gluten-free flours nutritional value 10% 13% 72% Wheat 1% 2% 11% 13% 73% Quinoa 2% 9% 14% Sorghum 1% 3% 5% 11% 63% 12% 80% Teff Buckwheat Oat Maize Rice 2% 4% 13% 10% 2% 4% 12% 13% 1% 7% 7% 10% 0% 2% 6% 14% 1% 1% 7% 13% 71% 69% 75% 78% 78% School of Food and Nutritional Sciences Nutritional Quality University College of GF Cork grains Ireland Protein content [%] Dietary fibre content [%] Folic acid [µg/100g] Calcium content [mg/100g] Iron content [mg/100g] Hager, A.-S., A. Wolter, et al. (2012). "Nutritional properties and ultra-structure of commercial gluten free flours from different botanical sources compared to wheat flours." Journal of Cereal Science 56(2):

11 Water level [% based on flour] Gluten-free flours baking properties Quality of gluten free breads inferior to wheat counterparts regarding taste attributes, loaf volume, crumb texture, microbial shelf life, staling Oat represents exception: sensory score and loaf quality comparable to wheat bread a b c SEM micrographs (1500/2000x) of wheat flour (a); dough (b), and bread (c). c a b c SEM micrographs (2200/2300x) of quinoa flour (a), dough (b) and bread (c) a b c SEM micrographs (1500/1000x) of maize flour (a), dough (b), and bread (c)

12 Hydrocolloids group of polysaccharides obtained from a variety of sources including trees, plants, seaweed and bacteria used in food products to control rheology and texture; stabilise emulsions (prevent coalescence and flocculation); control organoleptic properties (mouthfeel, flavour release) Produce highly viscous solutions, form gels with varying texture Impact of Hydrocolloids Gluten free model systems: No HPMC Weak structure Poor volume Dense, heavy texture With HPMC Gas retention High volume Porous structure

13 School of Food and Nutritional Sciences University College Cork Ireland Enzymes and their impact on gluten free model breads Enzymatic processing of GF flours Three different approaches have been considered Protein hydrolysis ENDOPROTEASE Hydrolysis of internal peptide bonds Increase of polar groups Decrease average MW Changes in molecular conformation Improve foaming properties Reduce interference with starch gel phase Direct enzymatic catalysis TRANSGLUTAMINASE formation of isopeptide bonds Production of reactive cross-linking agents LACCASE radical-generating oxidation of aromatic compounds Cross-linking of AX by esterification of FA residues Formation of S-S bridges GLUCOSE OXIDASE formation of H 2 O 2 in conjunction with glucose oxidation Formation of S-S bridges Gelation of water-soluble pentosans BAKING APPLICATION IN GF SYSTEM

14 Enzymes and their influence on GF -bread Screening of the effect of enzymes on gluten free cereals Transglutaminase, Laccase, Glucose oxidase & Protease Characterisation the impact on rheological properties Fundamental rheology, viscometry, creep-test, rapid visco-analyser G', G'' (Pa). G' 10 U/g G'' 10 U/g G' 1 U/g G'' 1 U/g 7000 G' 0 U/g G'' 0 U/g time (h) Impact of bread characteristics and ultra structure Texture profile analysis, image analysis, rheofermento-meter, laser scanning microscopy, electron-microscopy Understanding of the interactions Capillary electrophoresis, size exclusion chromatography, NIR, HPLC, SDS, 2D electrophoresis Transglutaminase Different GF-Raw-material Raw-material Buckwheat Brown rice Corn Oats Teff Sorghum Structur Positive Positive Positive None None None Rheology G G - G G - G G No changes No changes No changes Laser

15 TGase processing of GF flours Buckwheat Fundamental rheology of batters 30 SE-HPLC of protein fractions D gel of protein fractions 120 A 100 incubated mau G* (Pa) 1000 δ B control Frequency (Hz) retention time (min) Untreated Treated Overview on protease on gluten free raw materials Raw-material Rheology Viscosity Baking characteristics Buckwheat G* δ Negative: crumb defects G* δ - Improved: specific volume crumb hardness G* δ - - No effects G* δ Improved: specific volume crumb hardness G* δ - - No effects G* δ Brown rice Corn Oats Teff Sorghum slight specific volume

16 δ Protease processing of GF flours Oat Fundamental rheology of batters Capillary gel electrophoresis of total proteins from breads CLSM of breads G* (Pa) Frequency (Hz) Con Pr 0.01 Untreated Treated Untreated Treated Enzymatic treatments - Conclusions GF bread of higher quality can be produced by using enzymes TGase, GO, Laccase Laccase and GO Promote protein networks Promote arabinoxylans networks Proteases Improve foaming properties Reduce interference with starch gel phase (?) but keep in mind that each flour react differently to the various enzymes, and thus type and amount of enzyme have to be designed for the flour of interest

17 School of Food and Nutritional Sciences University College Cork Ireland In vitro starch digestibility and estimated glycaemic index of various gluten-free breads upon sourdough addition Glycaemic index The GI is defined as the incremental area under the curve (AUC) of the blood glucose concentration upon ingestion of a carbohydrate-containing food relative to reference food (glucose, GI glucose=100, or white wheat bread, GI white wheat bread=100) (Jenkins et al. 1981) Extent of increase of blood glucose concentration Characterisation of carbohydrate-containing foods into categories (Atkinson s table 2008) Glycaemic load: calculated from GI Insulin secretion taken into account Depending on type and amount of carbohydrates

18 Gluten-free foods and glycaemic index Prevalence for insulin-dependant diabetes mellitus 1-10% of coeliac patients (Goh 2007) Use of refined ingredients (starches, proteins) Necessity for blood glucose control High GI for reported for commercial gluten-free bread Number of publications with search term gluten-free and glycaemic index ; 12/03/2013; webofknowledge.com 34 Factors influencing glycaemic response Starch digestibility (size, type, AmL/AmP) Acid content Dietary fibre (Viscosity) Cooking Food processing Physical encapsulation Carbohydrate content Protein content Fat content

19 Baking Sourdough Weissella cibaria Lactobacillus plantarum Control breads Sourdough breads In vitro multi-enzyme dialysis Pepsin α-amylase Glass beads buffer kda sample Brennan 2008 In vitro glycaemic index Control breads 37

20 Starch digestibility Decrease GI Starch susceptibility Large starch granules High amylose content High dietary fibre (viscosity) High content of damaged starch High amount of gelatinised starch Increase GI Influence on in vitro GI Starch properties Increase GI Decrease GI Gelatinisation 71 C Teff 69 C Sorghum Size Quinoa <1-2 µm Buckwheat, Teff 5 µm Sorghum 10 µm Wheat 6/15 µm 66 C Buckwheat 61 C Wheat 58 C Quinoa 56 C Oat Sorghum, teff: Higher gelatinisation temperatures Oat-, sorghum- and teff Higher dietary fibre content Quinoa: Smallest granules Higher enzymatic starch susceptibility Lowest amylose content Reduced recrystallization Buckwheat: Low dietary fibre content 39

21 Influence of sourdough on glycaemic index Wheat Teff Sorghum Quinoa Oat Buckwheat Control W.cibaria MG1 L.plantarum FST1.7 20% sourdough addition: Reduced GI for wheat bread Gluten-free breads: Only in teff and sorghum with Lactobacillus plantarum It is possible to produce a Gluten free bread comparable to wheat bread

22 High fibre ingredients The right mix GF Cereals rich in fibre & micro-nutrients Enzymes Starch Water Hydrocolloids Protein Source Sourdough Further Reading

23 Funding European Commission in the Communities 6th Framework Programme, Project HEALTHGRAIN And Gluten-free Irish Government under the National Development Plan Enterprise Ireland University College Cork Dr Emanuele Zannini Dr Stefano Renzetti Dr Sandra Galle Dr Ann-Sophie Hager Dr Anika Wolters TU- Munich Prof. Rudi Vogel Dr. Juergen Behr Department of Food and Nutritional Sciences, University College Cork, Ireland Thank you very much for your attention!