FAV Health 2005 Quebec City, August 17-20 Dr Serge Mabeau Applied Research Center for plant breeding, biotechnology and quality. Specialised on main vegetable crops from Western France : Cauliflower, broccoli, artichoke, tomato, onion, shalot, potato
Antioxidant activity of extracts of artichoke and by-products Mrs Odile Chodosas, Dr Michel Surbled, Archimex, Vannes Dr Serge Mabeau, Mrs Céline Baty, BBV, St Pol de Léon Dr Pierre Métra, Lareal, Vannes Dr Christophe Chesné, Proclaim, Rennes
General objectives of the group : - Better knowledge of food composition with respect to health - Preparation of plant extracts with high antioxidant activity - Selection of the best extracts for further industrial implementations - Comparison between 2 methods of analysis of antioxidant activity
Content : results on artichoke - Raw material - Extraction methods - Extraction yield - Extract composition - Measure of antioxidant activity (ORAC) - Comparison of ORAC and Pholasin methods
Plant material Abundant and economically important crops in Western France : artichoke (cauliflower and buckwheat) Focus on by-product Simple extraction procedures
Frozen artichoke industrial process «solid» byproducts Peeling Bleaching Bleaching water Deep-freezing Storage
Antioxidant compounds from artichoke : polyphenols Cynaroside Caffeic acid Isorhoifolin Chlorogenic acid Cynarin Narirutin
Artichoke solid products / by-products Ethanol/water Extraction Filtration Solid products : simple extraction procedures Evaporation ethanol Freeze drying Extraction liquid-liquid Ethyl acetate «Raw extract» Organic fraction Aqueous fraction Solvant evaporation Freeze drying «Enriched extract»
Bleaching effluents : freeze drying
Polyphenol extraction yield Mg / kg of starting raw material 3000 2500 mg/kg wet matter 2000 1500 1000 500 0 Byproducts A : Byproducts A : Byproducts B : Artichoke heart : Bleaching raw extract enriched extract raw extract raw extract effluents Chlorogénic acid Narirutin Cynarin A Cynarin E Cynaroside Isorhoifolin Caffeic acid
Polyphenol composition of artichoke extracts content (g/100 g dry extract) 40,0 35,0 30,0 25,0 20,0 15,0 10,0 5,0 cynarin A isorhoifolin narirutin cynaroside caffeic acid cynarin E chlorgenic acid 0,0 Byproducts A : raw extract Byproducts A : enriched extract Byproducts B : raw extract Artichoke heart : raw extract Bleaching effluents
Correlation between HPLC and Folin - Ciocalteu methods for total polyphenol measure 40 40 35 35 30 30 total plyphenols (g/100 g) 25 20 15 25 20 15 10 10 5 5 0 Bleaching effluents Byproducts A : raw extract Byproducts A : enriched extract Byproducts B : raw extract Artichoke heart : raw extract 0 HPLC Folin Ciocalteu
Measure of antioxidant activity Principle of ORAC method : reaction in a spectrophotometer cuvette Reference method (first published in 93) Free radicals produced by AAPH (added at time zero) Destroy fluorescein Antioxidant in the mixture prevent this destruction Measure every 100 seconds
Measure of antioxidant activity Quantification = area under the curve Result expressed as micromole equivalent Trolox per kg
Antioxidant activity (ORAC method) and polyphenol content (HPLC) of artichoke extracts 8000 40 7000 35 6000 30 ORAC (µmoles TE/g) 5000 4000 3000 2000 25 20 15 10 total polyphenols g/100g 1000 5 0 0 Bleaching effluentsbyproducts A : raw Byproducts A : Byproducts B : raw Artichoke heart : extract enriched extract extract raw extract measured Orac total polyphenols HPLC
Artichoke extracts : polyphenol content (HPLC) allows the prediction of antioxidant activity (ORAC) 14000 12000 R 2 = 0.9967 10000 Orac (µmoles TE/100 g) 8000 6000 4000 2000 0 0 10 20 30 40 50 60 70 80 total polyphenols HPLC (g/100g)
Comparison between measured ORAC values and calculated ORAC value as the sum of individual polyphenol contributions 8000 7000 Orac (µmoles TE/g) 6000 5000 4000 3000 2000 caffeic acid cynarin A isorhoifolin narirutin cynaroside cynarin E chlorgenic acid measured Orac 1000 0 Bleaching effluents Byproducts A : raw extract Byproducts A : enriched extract Byproducts B : raw extract Artichoke heart : raw extract
Correlation between measured ORAC values and calculated ORAC value as the sum of individual polyphenol contributions 14000 12000 calculated ORAC (µmoles TE/g) 10000 8000 6000 4000 y = 0.7497x R 2 = 0.9958 2000 0 0 2000 4000 6000 8000 10000 12000 14000 measured ORAC (µmoles TE/g)
Measure of antioxidant activity Principle of Pholasin method : reaction in a spectrophotometer cuvette Pholasin = photo-protein of the marine mollusc Pholas dactylus Emits light in presence of free radicals and other reactive oxygen species Superoxide generated in situ (time zero, «solution B») Antioxidants in the mixture lower the luminescence Pro-oxidants enhance it Quantification = percent reduction (or increase) of peak luminescence Result expressed as micromole equivalent Trolox per kg
Measure of antioxidant activity : comparison between Pholasin and ORAC methods for artichoke extracts 16000 14000 12000 y = 1.0127x R 2 = 0.8917 Pholasin (µmoles TE/g) 10000 8000 6000 4000 2000 0 0 2000 4000 6000 8000 10000 12000 14000 Orac (µmoles TE/g)
Comparison between Pholasin measured values and calculated Pholasin value as the sum of individual polyphenol contributions 9000 8000 y = 0.5343x R 2 = 0.9149 calculated Pholasin (µmoles TE/g) 7000 6000 5000 4000 3000 2000 1000 0 0 2000 4000 6000 8000 10000 12000 14000 16000 measured Pholasin (µmoles TE/g)
Conclusion Antioxidant activity of artichoke extracts compared favourably to reference extracts Possibility of upgrading by-products from the industry (nutraceutical or «regular food» market) Potential of the Pholasin method for antioxidant activity measurement
Work under progress (to be completed by late 2005) Comparative work on : - Artichoke, cauliflower : products and industrial by-products - Buckwheat kernel (Polygonum fagopyrum) - Green tea (reference)
Thank you for your attention! mabeau@bbv.fr www.phytopole.com