Claire Mouquet-Rivier & Christèle Icard-Vernière UMR 204 NUTRIPASS, IRD, France

Transcription

1 Workshop: Improving the composition of plant foods for better mineral nutrition Food and Agriculture COST Action FA95: Mineral-improved crop production for healthy food and feed Claire Mouquet-Rivier & Christèle Icard-Vernière UMR 24 NUTRIPASS, IRD, France

2 Nutrient ingestion, nutrient absorption For all micronutrients, The quantity absorbed by enterocytes in the small intestine is much lower than the quantity ingested from the foods Vitamins Vitamin C: 85 % [75-1 %] depending on the intakes Folic acid : 85 % Vitamin B9 Food folate : 5 % Minerals Selenium : 9% Calcium : 35-7 % Zinc : 15-5 % Iron : 2-35 %

3 Micronutrients and absorption 3 main factors In humans In the foods Nutritional and physiological status Micronutrient form Food matrix Iron Zinc Calcium

4 Origins of micronutrients in foods Biofortification Extra-micronutrient -conventional breeding -GMO -Fertilizers Intrinsic Extrinsic Different forms of minerals naturally present in raw materials Total micronutrient content Contamination soil cooking utensils processing equipments Fortification

5 The case of iron Different forms of minerals 2 main forms Haem iron third form? Non haem iron Fe ++ Heme Myoglobin, hemoglobin Flesh foods: meat and fish 4% Mixt diet Intake 1-15% Absorbed > 4% Ferritin-iron Zhao et al (21) Hoppler et al (28) Mineral iron Fe +++ /Fe ++ Animal source food: -Meat and fish (6%) -Milk, egg Fe Plant foods: -Cereals -Vegetables ; leafy vegetables -Legumes

6 The example of iron Hurrell et Egli (21) Interactions mineral food matrix influence on absorption Inhibiting factors Activating factors Polyphenols -some phenolic acids -condensed Chelating tanins effect Phytates Iron Vitamin C -reducing/chelating Other organic acids Proteins - animal: milk, egg - soybean Oxalates Calcium Competition? Vitamin A, carotenoïds? Muscle proteins Non digestible polysaccharides Possible utilisation at colonic level?

7 Processing effects Two types of effect: Watzke, (1988) Mineral content Food matrix changes Other micronutrients -competition Chelating factors contents Activating factor contents Changes in the form : oxydation, denaturation «Retention» Absorption Quantity Quality

8 Processing effects On the retention/content : Losses processing including unit operation involving fractionation (separating) -Decortication -Grinding (if followed by sieving) -Soaking, blanching, boiling leaching of minerals Gains Contamination -From soil : harvest or post-harvest treatments -Mechanical grinding -Cooking utensils, cooking in hard water -Specific processing such nixtamalisation Formulation [Fortification]

9 Processing effects On bioavailability: Changes in chemical forms unit operations leading to denaturation -Thermal treatment - acidification ( fermentation?) unit operations leading to complexation Release of Fe++ from phytoferritin Non-haem iron pool Formation of soluble or insoluble complexes (Chelation) complex effects - Decortication : decrease mineral contents but also phytate, polyphenols, fibres - Soaking, germination, fermentation: endogenous or exogenous phytase activation - Cooking : controversial effects

10 Some examples Traditional food processing in Africa Tô - Cereal processing Family dish in Burkina Faso - Preparation of sauces from leafy vegetables

11 Processing effect is linked to mineral distribution in plant tissues Aleurone layer phytates minerals proteins Endosperm starch phytates pericarp polyphenols fibres scutellum germ lipids minerals 72 % phytates CIRAD J.F. CRUZ Structure of millet grain Effect of decortication? 11

12 losses (% DM) Effect of decortication on iron and zinc contents of millet and sorghum Abrasive decortication Iron Gampela millet White sorghum y=x extraction rate (%) losses (% DM) Zinc Gampela millet White sorghum Y=X extraction rate (%) Whole Millet Decorticated losses (%DM ) Phytate Gampela millet White sorghum y=x extraction rate (%) losses (% DM) Lipid Gampela millet White sorghum y=x extraction rate (%) Whole Sorghum Decorticated 12 Hama et al, (211)

13 Corundum grindstone Total iron content Metallic grindstone Mortar/pestle 12 1 b mg/1g DM b a,b a a b Porridge Pancakes 2 Tô Raw millet grains Washed Decorti cated Ground Dishes Processing steps

14 Total iron content 12 1 Contaminant iron? Intrinsic/extrinsic parts Food composition tables? 8 mg/1g DM intrinsic iron porridge pancakes Tô Raw millet grains Washed Decorti cated Ground Dishes Nutritional interest of contaminant iron? Processing steps Adish, 1999 / Hooda, 24

15 Bioaccessibility of iron in millet tô Millet flour: 3.7 mg/1 g DM 4 3 Iron content (mg/1g DM) 2 1 Total Dialysable Soluble ND Insoluble

16 Bioaccessibility of contaminant iron in millet tô Non contaminated flour : 3.7 mg/1 g DM Contaminated flour : 8.8 mg/1 g DM 1 non contaminated contaminated 8 Iron content mg/1g DM) Total Dialysable Soluble ND Insoluble - Most part insoluble - Small part soluble : could be bioavailable? Degradation of chelating factors Increase or protection of activators

17 Work on spinach Nafir-Zenati et al, Ashes mg/1 g DM Fe Cu (x1) Cu (x1) Fe g/1g DM crude leaves boiled leaves steamed leaves Important leaching during boiling (one third) Variable magnitude according to the mineral -Solubility -Involvement in complexes g/1g DM crude leaves boiled leaves steamed leaves crude leaves boiled leaves steamed leaves Ca Na Ca Na

18 8 7 Total iron Dialysable iron 6 5 iron content (mg/1g DM) High variability In content In behaviour during in vitro digestion roselle amaranth jute spinach-bf cleome

19 salt 19

20 % Dialysable iron % Slimy sauce Leaves Sauce Leaves Sauce Leaves Sauce Leaves Sauce roselle amaranth jute spinachcleome

21 Processing effects on mineral content ( retention ): -quite simple On mineral bioaccessibility -Complex and numerous versatile behaviour Biofortification : some questions arising Difficulty to develop predictive models Side-effects of biofortification on factors influencing bioavailability of minerals? Fate of extrinsic mineral through processing? -contamination -biofortification /GMO-conventional breeding fertilization: localisation of extra-mineral? Determining ideal processing intensity? - unit operations, method used and their parameters : t, T, yield, ph, etc. - mineral form