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Fordele og ulemper ved madlavning Eva Lydeking-Olsen FUB Oslo 2013 . Foredraget vil belyse hvad der er af fordele og ulemper ved forskellige måder at tilberede eller ikke-tilberede maden på. Vi vil gennemhulle en del af raw-foodmyterne/ læresætningerne og se på hvad der sker når maden opvarmes på forskellig vis og hvordan den påvirker os ift dannelse af toxiner som Acrylamid, Advanced Glycation Endproducts, oxidation af kolesterol mm ift specifikke fødegrupper og specifikker opvarmningsmetoder, herunder et kritisk blik på mikrobølgeovne. Microwave heating and human health effects – summary Neutral effects Beneficial effects •Vitamin loss •Protein denaturation •Cis-trans isomeration in PUFA •Thermic mutagens •N-3 EFA •Antigenic stability •Mineral balance •Oxidative damage : peroxides & anisidine •Antinutrients destroyed: Trypsin inhibitors Hemagglutinin activity Tannins Saponins •Glucosinolates increase in broccoli •Aflatoxin decrease •Mutagenic products decrease Potential problematic effects Not for human study Lead leaking from utensils •Amino acid isomerisation (Lubec 1989) •Acrylamide – reproduction •Extraction of toxic / damaging substances: Pesticides Mycotoxins Heavy Metals Feasible for a human study •Oxidized cholesterol •Flavonoids, broccoli •Isothiocyanates, broccoli •Repeat Blanc & Hertel, 1992, add reticulocytes •Oxidative stress: catalase, SOD, NO, glutathione reductaseand peroxidase Glutathione transferase Thioredoxin reductase Inflammatory / Acute Phase proteins Fordele ved at varme maden op Fordøjelighed& energitæthed Mindske ANTInutrienter Fytin Trypsinhæmmere Hæmagglutininer / Lektiner Saponiner Tanniner Denaturering proteiner Stivelse-forklistring Biotilgængelighed carotenoider oma Opvarmning Hygiejne *DESTRUKTION AF Virus Bakterier Parasitter Energimæssige faktorer & balancer Yin/Yang Syre/base Enzymer Livskraft Næringsstoffer ved opvarmning Typical Maximum Nutrient Losses (as compared to raw food) Vitamins Freeze Dry Cook 5% 50% 25% 35% 10% Alpha & beta Carotene 5% 50% 25% 35% 10% Beta Cryptoxanthin 5% 50% 25% 35% 10% Lycopen,Lutein+Zeaxanthin 5% 50% 25% 35% 10% Vitamin C 30% 80% 50% 75% 50% Thiamin 5% 30% 55% 70% 40% Riboflavin 0% 10% 25% 45% 5% Niacin 0% 10% 40% 55% 5% Vitamin B6, pyridoxin 0% 10% 50% 65% 45% Folat, fødevarer & tilsat folinsyre 5% 50% 70% 75% 30% Vitamin B12 0% 0% 45% 50% 45% Vitamin A, retinol; RAE Cook+Drain Reheat USDA Table of Nutrient Retention Factors (2003) Næringsstoffer ved opvarmning Typical Maximum Nutrient Losses (as compared to raw food) Minerals Freeze Dry Cook Cook+Drain Reheat Calcium Iron Magnesium 5% 0% 0% 0% 20% 35% 25% 40% 0% 0% 0% 0% 25% 40% 0% Phosphorus 0% 0% 25% 35% 0% Potassium 10% 0% 30% 70% 0% Sodium Zinc Copper 0% 0% 10% 0% 0% 0% 25% 25% 40% 55% 25% 45% 0% 0% 0% USDA Table of Nutrient Retention Factors (2003) Danmark: Dr. Kristine Nolfi; helbredte sin brystkræft ved hjælp af råkost 1941: Humlegården. Alma Nissen; helbredte sig selv for gigt ved hjælp af hvidløg, kartoffelvand og rå kost Brendal Helsehjem i Sverige. * Raw vegetarer (+æg og mejeriprodukter) * Raw veganer (minus animalsk) * Raw omnivorer (alt brugbart fra plante- og dyreriget) * Raw carnivorer ( kun fra dyreriget ) Raw Food USA : Ann Wigmore; helbredte sig selv for kræft ved hjælp af ”levende kost” 1968 Hippocrates Health Institute. ALTID MINDST 75 % rå mad. •Gourmet-Raw Food og består af ret meget fedt fra olier, nødder og kerner. • ”80-10-10” hvor 80% =kulhydrater fra frugt og grønt, 10% =fedt fra nødder/kerner og 10% =protein ligeledes fra frugt og grønt. •Solskinsmad er rå, uforarbejdede planter og frugter, nødder og kerner + kogte korn og ingen restriktioner om at maden skal være rå men det anbefales. Kogning af gulerod det øger indholdet af målbare carotenoider, der fungerer som antioxidanter. Raw Food Den kemiske struktur i kosten ændres ved opvarmning og nedsætter den næringsmæssige værdi og gør maden toxisk og uden liv – og tilfører derfor heller ikke liv til vores krop og celler. •Kogning kan nedbryde fødevarens cellevægge, så de sunde næringsstoffer frigives. • *Kogt tomat har for eksempel et langt højere indhold af lycopen, end friske tomater. *Broccoli der var stegt i ekstra jomfruolivenolie eller solsikkeolie havde samme c-vitaminindhold, som i den rå broccoli. Raw Food indeholder det højest mulige indhold af alle de nødvendige næringsstoffer … Raw Food Med Raw Food får du nemt dækket alle dine næringsbehov i form af vitaminer, mineraler, enzymer, fibre, antioxidanter, fedtsyrer, fibre, vand og oxygen. Vitaminer og mineraler Daglig anbefaling for ”kvinder 31-60 år” NNA 2004 Dagligt indtag i 2 ugers Raw Food Diæt. (gn.snit pr dag) Vitamin A i RE 700 1533,6 Vitamin D i mcg 7,5 0 Vitamin E i TE 8 39,4 Vitamin C i mg 75 445,5 Vitamin B1 i mg 1,1 1,8 Vitamin B2 i mg 1,3 1,5 Vitamin B3 i NE 15 21,3 Vitamin B6/mg 1,2 2,2 Folat i mcg 300 847,3 Vitamin B12 i mcg 2,0 0 Raw Food indeholder det højest mulige indhold af alle de nødvendige næringsstoffer … Raw Food Med Raw Food får du nemt dækket alle dine næringsbehov i form af vitaminer, mineraler, enzymer, fibre, antioxidanter, fedtsyrer, fibre, vand og oxygen. Vitaminer og mineraler Daglig anbefaling for ”kvinder 31-60 år” NNA 2004 Dagligt indtag i 2 ugers Raw Food Diæt. (gn.snit pr dag) Calcium i mg 800 620,8 Fosfor i mg 600 1107,4 Magnesium i mg 280 352,4 Kalium i mg 3100 4621,3 Jern i mg 15,9 15,3 Zink i mg 7 7,1 Kobber i mg 0,9 2,6 Selen i mcg 40 34,9 Jod i mcg 150 22,4 Chrom i mcg Ikke NNA 39,7 Mangan i mg Ikke NNA 4,7 Raw Food’er behøver tilskud af især Dvitamin, B12 og Kalcium God multivitamin med min 140 mcg. jod og 40 mcg. Selen = dækket ind på minimum. Jo mere vi tærer på eget lager, jo hurtigere ældes vi. Manglende enzymer kan betyde, at vi ophober affaldsstoffer og ufordøjede madrester der kan føre til træthed, forstoppelse, vægtøgning, inflammation og livsstilssygdomme på lang sigt. Faktisk kan du ved at spise mad med et højt indhold af enzymer, forøge mængden af kroppens egne naturlige enzymer – overskydende enzymer fra kosten bliver optaget i kroppes enzymdepoter, hvorfor de kan blive sendt rundt i kroppen, og indgå i tusindvis af livsvigtige processer. Raw Food Opvarmning ødelægger enzymer = kroppen tærer på sit eget enzymlager. NEJ. Raw Food Behovet for protein er forskellig fra person til person. NNA (2004) anbefaler 10-20% (helst 15% der svarer til ca. 0,75 g/kg kropsvægt) - til almindelige raske personer. En Raw Food diæt opfylder slet ikke dette anbefalede behov. Kun 5 dage ud af de 14 beregnede dage, sniger %-andelen sig op over de 10% = 4-5% fra det anbefalede daglige behov. På en enkelt dag er proteinindtaget helt nede på 5%. Raw Food Dag: Indtag pr dag, kcal: Overskud/ underskud/dag Person 1 Overskud/ underskud/dag Person 2. Mandag Tirsdag Onsdag Torsdag Fredag Lørdag Søndag 2447 3127 1930 1483 1894 2338 1467 +462 +1142 -55 -502 -91 +353 -517 +490 +1170 -27 -474 -63 +381 -490 Mandag Tirsdag Onsdag Torsdag Fredag Lørdag Søndag 1695 2223 2063 3185 1621 3302 1811 -290 +238 +78 +1200 -364 +1317 -174 -262 +266 +106 +1228 -336 +1345 -146 +2797 +3188 Samlet Raw Food Energi % fordeling Raw food gns. 14 dage NNA 2004 Protein 9.2 10-15 Fedt 60.5 25-35 Kulhydrat 30.3 55 ALT for højt fedt –indtag: Proinflammatorisk, mætheden ikke god nok ALT for lavt protein-indtag: Manglende mæthed, manglede byggesten til signalstoffer, vævsopbygning og nervesystem, nedadgående forbrænding Grøntsagers oxidative robusthed ift. opvarmning Markers of oxidative stress Am J Clin Nutr 2004;79:1060 –72 Several methods for measuring antioxidant activity Method Food Sample Human samples Oxygen Radical Absorbance Capacity (ORAC) x - ABTS = 2,2'-azino-bis(3-ethylbenzothiazoline-6sulphonic acid) x x TEAC Trolox Equivalent Antioxidant Capacity (often ABTS method) x x FRAP Ferric Reducing Capacity of Plasma (Trolox standard) - x MDA-TBAR Peroxidation of phospholipid liposomes x / Malondialdehyde-thiobarbituric adduct x Isoprostanes (oxidation of Arachidonic Acid) - x Plasma Cerbonyls (protein oxidation) - x AGE, Advanced Glycation Endproducts (glycotoxin in protein-fat rich foods) x x Markers of oxidative stress Biomarkers of plasma lipid and protein oxidation Antioxidant capacity markers Defense Enzyme Activities Plasma lipoprotein lag time FRAP assay (ferric reducing ability of plasma) Erytrocyte glutathione reductase (GST) Plasma lysine carbonyls Total plasma MDA (malon-di-aldehyde) LDL-MDA TEAC assay (spectrophotometric determination of antioxidant capacity) Isoprostanes in urine Oxygen consumption Glutathione peroxidase (Gpx) Catalase Superoxide dismutase Markers of oxidative stress J. Nutr. 133:2812-2819, September 2003 FRAP (mmol Fe2+/kg FW3) TRAP (mmol Trolox/kg FW) TEAC (mmol Trolox/kg FW) Fruit Value Rank Value Rank Value Rank Apple (red Delicious) 3.84 24 2.23 20 1.59 22 Apple (yellow Golden) 3.23 26 1.54 24 1.31 25 Apricot 4.02 23 2.29 19 1.44 24 Banana 2.28 28 1.05 27 0.64 30 Blackberry 51.53 1 21.01 1 20.24 1 Blueberry 18.61 9 9.30 7 7.43 10 Cherry 8.10 16 4.17 12 2.69 16 Clementin e 8.88 15 2.74 16 3.10 14 Fig 5.82 20 2.06 21 2.47 18 Markers of oxidative stress …TEAC assay is done both in foods and biological fluids J. Nutr. 133:2812-2819, September 2003 FRAP (mmol Fe2+/kg FW3) TRAP (mmol Trolox/kg FW) TEAC (mmol Trolox/kg FW) Vegetable Value Rank Value Rank Value Rank Artichoke 11.09 12 6.85 3 1.55 20 Arugula 14.30 7 4.22 10 3.55 9 Asparagus 10.60 13 9.71 1 3.92 7 Avocado 4.90 21 1.87 21 2.22 15 Beet 13.13 8 2.70 16 5.21 5 Beetroot (red cooked) 15.31 6 7.67 2 2.94 13 Broccoli 11.67 9 3.07 12 3.04 12 Cabbage (green) 5.79 17 2.83 14 1.15 24 Cabbage (Savoy) 8.17 14 2.35 18 2.08 16 Study Isothiocyanates, broccoli. Cancer preventive, detoxifying. Flavonoids, broccoli. Important phytonutrients with antioxidant and detoxifying effects, minimizing genetic damage in cells. Organic broccoli (var. Marathon) was heated by 4-6 methods under standardized conditions and samples taken for analysis. • Microwave 1000 Watt (full effect) • Boiling covered with water, variable time for broccoli (minutes) • Induction heating, with and without water • Steaming without water contact, – both electrical and induction (minutes) Isothiocyanates in broccoli Sulphur – containing phytonutrients = glucosinolates Converted to isothiocyanates, ITCs, by the myrosinase enzyme Active compound isothiocyanate is measured in food or urine Proces Broccoli with glucosinolates and residual enzyme activity + Cutting in to smaller pieces or chewing = •Protection from DNA damage •Inhibit cancer formation •Detoxify environmental pollutants •Convert estrogen to less biologiacally forms (16 OH to 2 OH) •Inhibit several cancer forms After cutting the broccoli, short term heating (30- 60 sec) is considered the best way to prepare the broccoli for optimum health benefit. (Smith 2003). Isothiocyanates in broccoli Samples • Organic broccoli, var. Marathon • Grown i Italy • One batch from the ecological retailer Solhjulet • Aliquots of 200 g of flower and small stems No flavonoids and little isothiocyanates in the stalk and, and heated according to table. - Sample were divided in two portions of 100 g - One for flavonoid analysis - One for analysis of isothiocyanates. - Samples for analysis of flavonoids were frozen at -20 ºC (Pia Knuthsen), isothiocyanates prepared and analyzed immediately (Mette Kristensen). Result : Isothiocyanates in broccoli Best culinary quality is considered crisp (al-dente) with a clear green color, obtained at 1-2 minutes heating 3500 nmol ITC/g broccoli 3000 2500 2000 •All heating with water contact, MW at low effect/longer time and steaming 4 and 10 min destroy enzyme activity. 1500 1000 500 0 1 min 2 min 4 min 10 min Mikrobølge, 900W Induktion kogning Alm. kogning Induktion dampning Alm. dampning Rå, ubehandlet * Short –term heating, 1 and 2 minutes is culinary good, results are summarized in figure. Flavonoids Some of the most important phytonutrients •antioxidant •other physiologically important regulatory effects •minimizing genetic damage and cancer development ( laboratory) •improving the liver capacity of detoxifying environmental pollutants and carcinogenic hormones. Earlier studies 1. Ioku found better retaining of flavonoids in MW without water, similar to oil-frying whereas boiling in water leaked the flavonoids ~ 30 % to the water If the cooking-water is used there is no health effects (Ioku 2001). 2.Vallejo found that broccoli boiling in water and pressure cooking created a loss of flavonoids of 66% and 47%, respectively. MW with added water almost completely destroyed the flavonoids with a 97 % loss, whereas steaming retained the flavonoids completely (Vallejo 2003). 3.Apigenin from parsley has been shown to be microwave stable (Nielsen 1999). Result:Flavonoids in broccoli Figure 4. Change in flavonoids i broccoli, raw and after different heating methods. Aglycones, mg/100g, corrected for fluid loss/uptake 12,0 mg/100g 10,0 8,0 6,0 4,0 2,0 0,0 raw steaming, 1 steaming, 2 mikro, 900 mikro, 900 min min W, 1 min W, 2 min Quercetin Kaempferol mikro, 500 mikro, 150 W, 8 min W, 24 min Result: Flavonoids in broccoli % Figure 5. Percent change in flavonoids in broccoli after different heating methods and compared to raw. Aglycones, mg/ 100g and corrected for fluid loss/uptake 80,0 60,0 40,0 20,0 0,0 -20,0 -40,0 0 15 o, 0 50 o, 0 90 o, 0 90 o, W W W W in in in in m m m m 4 ,2 ,8 ,2 in ,1 m in Kaempferol icr icr icr icr 2 g, m Quercetin m m m m in m ea st 1 g, -80,0 in m ea st -60,0 Flavonoids in broccoli No differences were found between the heating methods steaming and MW at one minute, the only culinary interesting method. Both methods produced a loss of ≈ 40 % for Quercetin and ~ 20% for kaempferol. Highly variable response to different heating methods for vegetables with respect to different analysis of antioxidant capacity……………………………………. The influence of home cooking methods (boiling, microwaving, pressure-cooking, griddling, frying, and baking) on the antioxidant activity of vegetables has been evaluated in 20 vegetables, using different antioxidant activity assays (lipoperoxyl and hydroxyl radicals scavenging and TEAC). Artichoke was the only vegetable that kept its very high scavenginglipoperoxyl radical capacity in all the cooking methods. The highest losses of LOO. scavenging capacity were observed in cauliflower after boiling and microwaving, pea after boiling, and zucchini after boiling and frying. Beetroot, green bean, and garlic kept their antioxidant activity after most cooking treatments. Swiss chard and pepper lost OH. scavenging capacity in all the processes. Influence of cooking methods on antioxidant activity of vegetables. Jiménez-Monreal AM, García-Diz L, Martínez-Tomé M, Mariscal M, Murcia MA. J Food Sci. 2009 Apr;74(3):H97-H103. Highly variable response to different heating methods for vegetables with respect to different analysis of antioxidant capacity……………………………………. Celery increased its antioxidant capacity in all the cooking methods, except boiling when it lost 14%. Analysis of the ABTS radical scavenging capacity of the different vegetables showed that the highest losses occurred in garlic with all the methods, except microwaving. Among the vegetables that increased their TEAC values were green bean, celery, and carrot after all cooking methods (except green bean after boiling). These 3 types of vegetables showed a low ABTS radical scavenging capacity. According to the method of analysis chosen, griddling, microwave cooking, and baking alternately produce the lowest losses, while pressure-cooking and boiling lead to the greatest losses; frying occupies an intermediate position. In short, water is not the cook's best friend when it comes to preparing vegetables. Influence of cooking methods on antioxidant activity of vegetables. Jiménez-Monreal AM, García-Diz L, Martínez-Tomé M, Mariscal M, Murcia MA. J Food Sci. 2009 Apr;74(3):H97-H103. Highly variable response to different heating methods for vegetables with respect to different analysis of antioxidant capacity……………………………………. 20 10 0 -10 Boiling Pressure -20 Baking Microwave -30 Griddling Frying -40 -50 -60 -70 Lipidscavenging, LOO radical, % change from raw control Highly variable response to different heating methods for vegetables with respect to different analysis of antioxidant capacity…… 0 20 10 -5 -10 -15 -20 Series1 artichoke asparagus beetroot broad been broccoli brussel sprouts cauliflower carrot celery eggplant garlic green bean leek maize onion pea pepper spinach swiss chard zucchini 0 -10 -30 -20 -40 -25 -50 -30 -60 -35 -70 Lipidscavenging, LOO radical, % change from raw control Median all vegetables Lipid-scavenging, LOO radical, % change from raw control MW, individual vegetables Series1 Highly variable response to different heating methods for vegetables with respect to different analysis of antioxidant capacity……………………………………. 60 40 20 Boiling 0 Pressure Baking -20 Microwave Griddling -40 Frying -60 -80 -100 Scavenging OH radical, % change from raw control Highly variable response to different heating methods for vegetables with respect to different analysis of antioxidant capacity……………………………………. 0 60 -2 40 -4 20 -6 -8 Series1 -20 -10 -40 artichoke asparagus beetroot broad been broccoli brussel sprouts cauliflower carrot celery eggplant garlic green bean leek maize onion pea pepper spinach swiss chard zucchini 0 Series1 -12 -60 -14 -80 -16 Scavenging OH radical, % change from raw control, median all vegetables, all heating methods Scavenging OH radical, % change from raw control, individual vegetables, MW Highly variable response to different heating methods for vegetables with respect to different analysis of antioxidant capacity……………………………………. 250 200 150 boiling 100 pressure baking Microwave 50 griddling frying 0 -50 -100 ABTS anion radical scavenging, % change from raw control Highly variable response to different heating methods for vegetables with respect to different analysis of antioxidant capacity……………………………………. 200 20 15 150 10 100 Series1 5 0 Series1 50 0 -5 -50 ABTS anion radical scavenging, % change from raw control, mean all vegetables, all heating methods ABTS anion radical scavenging, % change from raw control, individual vegetables, MW Dannelse af toxiner ved opvarmning Oxidation af kolesterol Acrylamid Heterocykliske aminer (HCAs) Polycykliske aromatiske hydrocarboner (PAHs). Advanced Glycation Endproducts Dannelse af toxiner ved opvarmning Acrylamid Acrylamide….. . Effects of consumer food preparation on acrylamide formation. Jackson LS, Al-Taher F. Adv Exp Med Biol. 2005;561:447-65 Source U.S. Food and Drug Administration, National Center for Food Safety and Technology (NCFST), 6502 S. Archer Rd., Summit-Argo, IL 60501, USA. Lauren.Jackson@cfsan.fda.gov Abstract Acrylamide is formed in high-carbohydrate foods during high temperature as frying, baking, roasting and extrusion. Although acrylamide is known to form during industrial processing of food, high levels of the chemical have been found in home-cooked foods, mainly potato- and grain-based products. This chapter will focus on the effects of cooking conditions (e.g. time/temperature) on acrylamide formation in consumer-prepared foods, the use of surface color (browning) as an indicator of acrylamide levels in some foods, and methods for reducing acrylamide levels in homeprepared foods. As with commercially processed foods, acrylamide levels in homeprepared foods tend to increase with cooking time and temperature. Acrylamide………… In experiments conducted at the NCFST, acrylamide levels in cooked food depended greatly on the cooking conditions and the degree of "doneness", as measured by the level of surface browning. • French fries fried at 150-190 ˚C for up to 10 min had acrylamide levels of 55 to 2130 microg/kg (wet weight), with the highest levels in the most processed (highest frying times/temperatures) and the most highly browned fries. • "dark" toasted bread slices had 43.7-610.7 microg/kg wet weight, compared to "light" at 8.27-217.5 microg/kg or "medium" at 10.9-213.7 microg/kg •Analysis of the surface color by colorimetry indicated that some components of surface color ("a" and "L" values) correlated highly with acrylamide levels. •Soaking raw potato slices in water before frying was effective at reducing acrylamide levels in French fries. •Additional studies are needed to develop practical methods for reducing acrylamide formation in home-prepared foods without changing the acceptability of these foods. The effect of domestic preparation of some potato products on acrylamide content. Michalak J, Gujska E, Klepacka J. Plant Foods Hum Nutr (2011) 66:307–312 Source Food Science Department, University of Warmia and Mazury, ul. Heweliusza 6, Olsztyn, Poland. seniutaj@uwm.edu.pl Abstract The influence that food heating has on the concentration of acrylamide in home-cooked potato dishes prepared by high-temperature, such as pan-frying, deep-frying, roasting and microwave heating was analyzed. The experiment was performed with commercially available deep-frozen par-fried French fries and deep-frozen par-fried potato products other than French fries (cubes, wedges, noisettes, pancakes). Acrylamide was found in all deep-frozen par-fried French fries and other deep-frozen par-fried potato products before domestic preparation. The mean level of acrylamide content in all frozen potato products before preparation was found to be 322 μg/kg. Potato products were then prepared at 180 °C for 3 min and at 220 °C for 10 min. After domestic preparation (roasting, pan-frying, deep-frying and microwave heating) it was found that the level of acrylamide in all products increased. Acrylamide content in the analyzed samples significantly increased as the temperature and time of processing increased. The statistical analysis showed significant differences (P < 0.05) for acrylamide content as a function of food preparation. The level of acrylamide increased with the increased heating temperature and heating time. Additionally, the preparation method of roasting was significantly lower in acrylamide content (P < 0.05) than the preparation method of microwaving although both preparation methods used the same conditions (time and temperature). These results suggest that microwaving might be more favourable to the formation of acrylamide than conventional heating methods, such as roasting. French fries Crinkle, n=5 each Thick-cut, n=3 each Shoestring, n=3 each Preparation methods mean±SD Before final preparation 410±41 Pan-frying Deep-frying Roasting Microwaving 535±49 539±45 660±51 744±72 Before final preparation 358±81 Pan-frying Deep-frying Roasting Microwaving 527±39 568±41 704±68 763±55 Before final preparation 480±11 Pan-frying Deep-frying Roasting Microwaving 622±10 685±15 817±17 863±25 A Mean ± standard deviation, n = The number of the same type of products Acrylamide content of potato products before final preparation and after different domestic preparation methods , (μg/kg) Acrylamide content of potato products before final preparation and after different domestic preparation methods (μg/kg) Other potato products Cubes, n= 3 each Wedges,n=3 each Noisettes, n=3 each Pancakes; n=3 each Preparation methods Acrylamide (μg/kg) Pan-frying 341±17 Deep-frying Roasting Microwaving 392±18 527±28 679±70 Before final preparation 197±18 Pan-frying Deep-frying Roasting Microwaving 436±18 451±19 588±22 635±30 Before final preparation 337±16 Pan-frying Deep-frying Roasting Microwaving 387±19 405±7 547±9 696±12 Before final preparation 286±2 Pan-frying Deep-frying Roasting Microwaving 437±11 422±13 564±10 694±11 Statistical analysis for the effect of preparation methods on the acrylamide content of potato products, (μg/kg) Method Before final preparation Pan-frying Deep-frying Roasting Microwaving French fries, n = 11, Other potato products, n = 12, All products, n = 23, B416±61a C252±72a D322±154a B561±53b C400±46b D469±109b B597±67b C418±53b D495±114b B727±71c C557±51c D630±100c B790±64d C676±59d D725±107d A Mean ± standard deviation, a, b, c, d – Mean in columns followed by the same letter are not significantly different (P ≤ 0.05) A comparative study of acrylamide formation induced by microwave and conventional heating methods. Yuan Y, Chen F, Zhao GH, Liu J, Zhang HX, Hu XS. J Food Sci. 2007 May;72(4):C212-6 Source College of Food Science & Nutritional Engineering, China Agricultural Univ., Beijing, 100083, China. Abstract In this study, the formation of acrylamide upon treatment with microwave and conventional heating, boiling, or frying was investigated in both Asn/Fru and Asn/Glc model systems and in potato chips. Acrylamide levels were analyzed by HPLC method, which was confirmed by HPLC-MS/MS. Present results in model systems showed that pH value had a complex influence on the formation of acrylamide in the 2 systems during both microwaving (600 W) and boiling (120 +/- 1 degrees C). At pH < 8.0, acrylamide content increased with increasing the pH value, reaching the maximum at pH 8.0 whereas acrylamide content decreased with the increase of pH. Regardless of pH and heating methods, acrylamide content generally increased with increasing treatment time. Surprisingly, all present results showed that microwave heating not only induced acrylamide formation in the 2 model systems but also facilitated more acrylamide to be formed as compared to the boiling method at identical pH and treatment time. At pH 4.0, 8.0, and 10.0, the larger the microwave power, the more the acrylamide content. Consistent with the above observation, treatment of potato chips with microwave heating for 2.5 to 3.5 min in the range 550 to 750 W similarly resulted in acrylamide formation. The highest acrylamide content was formed by 750 W microwave treatment as 0.897 +/- 0.099 mg/kg, which was significantly higher than that produced by traditional frying (180 +/- 1 degrees C), 0.645 +/- 0.035 mg/kg (P < 0.05). Acrylamide……….. • Less AA with MW in popcorn compared to conventional heating , but high levels in sugar- varieties Wei Sheng Yan Jiu. 2007 Mar;36(2):220-2 • No formation of AA in cooking of vegetables in MW • Shokuhin Eiseigaku Zasshi. 2004 Feb;45(1):44-8. • Higher formation of AA in selected vegetables if pre-cooked in MW and then baked, compared to pre-cooking by boiling and then baking Shokuhin Eiseigaku Zasshi. 2004 Feb;45(1):44-8. Grillet kød er farligt Heterocykliske aminer (HCAs) HCAs dannes ved meget høj temperatur eller flammer Forskellige HCAs dannes, som amino-imidazoquinolin, amino-imidazo-quinoxaliner, aminoimidazo-pyridiner, and aminocarboliner. HCAs forårsager DNA skader og er formentlig en faktor I udviklingen af forskelige kræftformer Polycykliske aromatiske hydrocarboner (PAHs). PAHs dannes når fedt drypper ned på grillkullene og ryger…fx.benzo- pyren og dibenzo[a,h]anthracen, som klistrer sig på kødets yderside. Kræftfremkaldende. Fornuftigere brug af grill…….. 1.Magert kød. -drypper mindre fedt og dermed mindre PAH-fyldt røg 2.Mariner kød før grill´ning HCA kan reduceres med op til 90 % , måske pga barrierefunktion 3.Lavere temperatur 4.Undgå flammer Flammer forårsager både HCAs og PAHs. 1.Oversteg IKKE kødet. Fjerkræ , fisk, skaldyr og hakket kød skal gennemsteges, men ikke mere end det, brug termometer. Advanced Glycation Endproducts AGEs Advanced Glycation Endproducts AGEs AGEs- advanced glycation endproducts – Maillard reaction / roasting process AGEs in food……….. • Worst is high protein-high fat foods w. endogenous cellular sugar, producing ”glyco-toxins”: • Meat, nuts, fats • Worst is heating w. higher temperature/ longer time or ”maturing ” cheese (parmesan) J.Am.Diet.Ass.2010;110:911- 16 • Better is acidic environment (marinade w. lemon or vinegar) • Better is shorter time, ie MW • Better is grains, vegetables, pure sugar-foods and milk products AGEs in food…..database available Food item J.Am.Diet.Ass.2010;110:911-16 AGE, kU/100 g Butter Beef, raw 26.480 800 Beef, grilled 4 min 7.416 Beef, Microwaved , 6 min 2.687 Beef, pan fried , olive oil 10.058 BACON, 5 min no oil 91.577 BACON, 3 min MW 9.023 Chicken breast, skinless , raw 769 Chicken breast, skinless , pan fried 13 min, high tp 4.938 Chicken breast, skinless , poached 15 min 1.076 Chicken breast, skinless , microwaved 5 min 1.524 …similar for many other protein rich foods…….. AGEs in food…..database available J.Am.Diet.Ass.2010;110:911-16 Food item Lamb, raw/ boiled 30 min Parmesan vs. cottage cheese 1% Egg, no oil, all types Potato boiled vs. French fries Cashew raw Pine seeds, raw Pistacie, raw Sunflower raw vs. roasted Peanuts Roasted vs. Roasted in shell SOY beans roasted and salted AGE, kU/100 g 826 /1.218 16.900/1.453 43-90 27 / 1522 6.730 11.210 380 2510/4693 8.333/3.440 1.670 Metabolomics, KU LIFE …………PhD study currently running LOW AGE- basis diet 5 day before and 2 days after each test meal Low AGE Test meals: Raw Minimal processing Bacon Low preparation time Milk Powder Boiling/steaming Oil Vegetables High AGE Frying Grilling Longer-time cooking This test meal is ALSO a high-oxysterol meal……. Oxidation af kolesterol Intact LDLcholesterol Oxidized cholesterol, broken apart – particles infiltrates arterial wall LDL cholesterol appears intact in the lower-left corner while oxidized cholesterol that has broken apart is shown in the background as it infiltrates the damaged arterial wall along with red blood cells. www.renderosity.com/.../folder_9/file_435308.jpg Primary cholesterol oxygenation reactions mediated by * cytochrome P-450 species *occurring nonenzymatically in the presence of reactive oxygen species (ROS) Oxygenation of cholesterol into 25-OH cholesterol is catalyzed by cholesterol 25hydroxylase, a non-heme iron protein Björkhem 2002 Oxycholesterol boosts total cholesterol levels Promotes atherosclerosis more than nonoxidized cholesterol. Fried and processed food, particularly fastfood, contains high amounts of oxycholesterol. Avoiding these foods and eating a diet rich in antioxidants: Fresh fruits, berries and vegetables, may help reduce its levels in the body. Added to processed foods, those substances improve texture, taste and stability Source: 238th National Meeting of the American Chemical Society 2009. Zhen-Yu Chen, PhD Chinese University of Hong Kong (Photo Credit: Wikimedia Commons) Alzheimer's and oxidized cholesterol: Neighbors come together Lipidomics Gateway (26 August 2009) [doi:10.1038/lipidmaps.2009.20] An oxidized form of cholesterol alters membrane organization and might disrupt cellular function in Alzheimer's disease. Alzheimer's disease is characterized by accumulation of the neurotoxic peptide β-amyloid. This peptide can oxidize cholesterol to form the oxysterol 7β-hydroxycholesterol 1 (7β-OH). Although cholesterol in cell membranes brings neighboring phospholipid molecules closer together, by inducing a partial straightening of their acyl chains, the effect of 7β-OH on membrane organization is unknown. Now Steven Regen and colleagues report in the Journal of the American Chemical Society that the condensing effect of 7β-OH is enhanced compared to that of cholesterol. This produces a membrane reorganization that might help to explain the enigmatic etiology of Alzheimer's disease. 7β-hydroxycholesterol is produced by oxidation of cholesterol Mitomo, H., Chen, W.H. and Regen, S.L. Oxysterol-induced rearrangement of the liquid-ordered phase: a possible link to Alzheimer's disease?. J. Am. Chem. Soc. (6 August 2009). doi:10.1021/ja904308y Oxidized cholesterol test feeding Background: Information on the absorption of cholesterol oxidation products (COP) from ordinary foodstuff in humans is scarce. Methods: Five healthy young men were offered a 150 g salami + 150 g Parmesan+ 135 g bread, a meal naturally rich in COP. Plasma and lipoprotein COP concentrations were measured over 9 h. Results: The mean plasma free (nonesterified) COP concentration showed its maximal increase 3 and 5 h after meal consumption. In contrast, the raise in plasma total COP concentration began 6 h after the meal with a maximum at 8 h and was statistically significant for 7·- and 7ßhydroxycholesterol and 7-ketocholesterol. Conclusion: COP from ordinary foodstuff were absorbed in the human intestinal tract but differences in the bioavailability of the single COP compounds were found. Dr. Jakob Linseisen/ Günther Wolfram Institute of Nutrition Science of the Technical University of Munich, Germany. Ann Nutr Metab 1998;42:221–230 Peak 3 hrs. • Alpha- epoxide • 7- keto : triple from 75,4 nmol/l at baseline to 235 nmol/l • Cholestanetriol Peak at 5 hrs. • 7- α – OH- cholesterol • 7-β – OH- cholesterol Doubles from 40 nmol/l to 87 nmol/l • Cholesterol- β- epoxide 25-OH- Cholesterol The role of endoplasmic reticulum stress in the progression of atherosclerosis. Tabas I. Circ Res. 2010 Oct 1;107(7):839-50. Source Department of Medicine, Columbia University, New York, NY 10032, USA. iat1@columbia.edu Abstract Arterial wall stressors may be especially prominent in the settings of obesity, insulin resistance, and diabetes, all of which promote the clinical progression of atherosclerosis. In macrophages, prolonged ER stress triggers apoptosis, leading to plaque necrosis if the apoptotic cells are not rapidly cleared. ER stress-induced endothelial cell apoptosis may also contribute to plaque progression. Another potentially important proatherogenic effect of prolonged ER stress is activation of inflammatory pathways in macrophages and, perhaps in response to atheroprone shear stress, endothelial cells. The role of endoplasmic reticulum stress in the progression of atherosclerosis. Tabas I. Circ Res. 2010 Oct 1;107(7):839-50. Source Department of Medicine, Columbia University, New York, NY 10032, USA. Prolonged activation of the endoplasmic reticulum (ER) stress pathway,known as the unfolded protein response (UPR) can lead to cell pathology and subsequent tissue dysfunction. Ample evidence that the UPR is chronically activated in atherosclerotic lesional cells, particularly advanced lesional macrophages and endothelial cells. The stressors in advanced lesions that can lead to prolonged activation of the UPR include oxidative stress, oxysterols, and high levels of intracellular cholesterol and saturated fatty acids. Oxycholesterol- biological effects Oxycholesterol, may pose the greatest heart disease risk. Study on hamsters (Chen, Hong-Kong 2009): •Diet high in oxycholesterol Vs. Diet with non-oxidized cholesterol Outcome : •Blood cholesterol + 22 % in oxy-cholesterol group •Greater deposition of cholesterol in the lining of blood-vessels (atherosclerotic plaques) Plaques increase the risk for heart attack and stroke. Oxycholesterol had undesirable effects on artery function: Reduces the elasticity of arteries, impairing their ability to expand and carry more blood. Time-of-year-result, study 1 + 2 Second heating study T-test May vs. January p-value Raw 0,321 MW 0,001 Oven 0,001 Boiling 0,001 Steaming 0,10 Wok 0,008 Induction 0,036 Teflon pan 0,011 Pooling of data, first study 1400.0 1200.0 1000.0 All 3 oven methods were similar: Convection, hot-air and common electric oven, n=18 Two boiling methods: Water boiling on electric stove and pressure boiling on electric stowe, n=12 Three frying methods: Teflon pan, easy slip 800.0 Alpha-Epoxy 7-beta-OH 7-Keto 600.0 Beta-Epoxy Total oxy 400.0 200.0 0.0 Wok gas,n=6 Induction, n=6 Raw,n=3 All oven, n=18 Boiling, n=12 Frying,n=18 MW, n=6 Steaming,n=6 Second heating study Overall result, n=12 raw and n=9 in each group Overall ranking from high to low, at significant p-values: 1. boiling 2. MW 3-6. similar: wok, steaming, oven, induction 7. teflon 8. control Intermediate/ Selected methods heating study Fig.12. 7-beta-OH-cholesterol Stepwise regression: group, at p=0,026 and weight change at P=0,028 Univariate analysis w. Bonferroni at 0,01 *Control significantly different from: - Boiling, MW and oven *Wok gas significantly different from:None *Boiling significantly different from: - Control, teflon, steaming, induction and oven *Teflon significantly different from: - Boiling, MW *MW significantly different from: - Control, teflon, steaming, induction, oven *Steaming significantly different from: - MW, boiling * Induction significantly different from: - Boiling, MW *Oven significantly different from: - Control, boiling, MW Intermediate/ Selected methods heating study Fig. 13. Total Oxy-cholesterol/Total COPs Stepwise regression: Group, at p= 0,024 and weight change p=0,045 Univariate analysis w. Bonferroni at 0,01: *Control significantly different from: Boiling, teflon, MW, steaming, oven *Wok gas significantly different from: none *Boiling significantly different from: - Control, teflon, induction *Teflon significantly different from: - Boiling, MW * MW significantly different from: - Control, teflon, steaming, induction * Steaming significantly different from: - Control, MW *Induction:- Boiling, MW *Oven significantly different from: - Control Possible to reach high enough levels of COP with 75°C heated chicken ?? Amount of COP per portion of 150 g edible portion ≈ 50 g dry weight 7-beta -OH, a-epoxy, nmol nmol 7- keto, nmol b-epoxy, nmol Total oxy cholesterol nmol 15,74 123,61 23,61 107,75 270,72 Teflon pan 27,50 113,50 57,00 271,50 469,94 MW 90,50 158,00 180,00 532,00 960,00 Boiling 117,01 200,20 205,76 625,31 1148,28 Raw Added spices…….and a good quality oil Organic greek extra- virgin olive oil w. lemon – 1 tbs. In preparation Organic rosemary (Rosmarinus Officinalis), from www.Sonnentor.com ≈ 3 tsp. added before heating Organic/bio turmeric (Curcuma) from www.lebensraum.de ≈ 3 tsp. added before heating Let sit for 15 min before preparation Level of spices high, compared to European tradition, but with fine taste. 7-betaHydroxycholesterol after heating with spices turmeric, rosemary and olive oil, n=2 300.0 250.0 200.0 150.0 100.0 50.0 0.0 7-beta-Hydroxycholesterol 1. Slight increase in MW + spices, 2. Large increase in induction + spices, almost 3-fold from 87 ng/g to 263 ng/g 3. 28% decrease in oven + spices -compared to the same without spices Beta-Epoxy-cholesterol after heating with antioxidant spices turmeric, rosemary and olive oil, n=2 500.0 450.0 400.0 350.0 300.0 250.0 200.0 150.0 100.0 50.0 0.0 beta-Epoxycholesterol 1. 58% decreased oxidation in MW + spices, 2. 38 % increase in induction + spices 3. 17% % decreased oxidation in oven + spice compared to the same without spices Conclusion • The study has revealed a significant trend for formation of COPs in different heating methods of organic chicken breast. • Study 1: Wok, teflon pan and Induction = gentle heating Electric heating = intermediate, regardles of method Steaming, boiling and microwave = aggressive. • Study 2: Teflon (green pan) = gentle Wok, streaming, oven, induction= intermediate Boiling, microwave = aggressive Conclusion • Findings are highly relvant for public health on the real large scale…………it is findings who, if applicated, studied and expanded further – can contribute to save both lives and quality of lives. • Alone i EU 25 (ie not worldwide) there is 741.000 coronary heart disease deaths, per year. • Oxidized cholesterol is thought to be a major contributing preventable cause. Konklusion • INGEN enkle resultater eller handlinger på området • VARIATION Kulhydrater /stivelse: hellere kogt /langtidsbagt ved lav temperatur / låg på Grøntsager: Mange RÅ, Nogen kan lide opvarmning Proteiner & fedt: Så LAV temperatur og så KORT tid som muligt Tak for i dag SPØRGSMÅL?? Is it possible to reach high enough levels for significant clinical result of total COP with 75°C heated chicken ?? • Linseisen 1998 = used 8,846 µmol total COP / portion /923 mg cholesterol with salami and parmesan • Emmanuel 1991 = used 28 µmol total COP / portion with spray dried egg powder • • • • • Present study 2011; ranges pr. 150 g edible portion chicken/ est. 33 % DM Raw 270,72 nmol ≈ 0,271 µmol Teflon 469,94 nmol ≈ 0,470 µmol MW 960,00 nmol ≈ 0,960 µmol Boiling 1148,28 nmol ≈ 1,148 µmol = Result : Isothiocyanates in broccoli Total ITC formation in broccoli after the different heat treaments (nmol/g) Treatment 0 min 1 min 2 min 4 min 10 min Raw 3185.4 ±17.5 3178.6 ± 53.0 still raw 231.6 ± 170.2 Green, crisp 121.1±39.3 114,3 ± 29.9 Induction steaming 171,5 ± 53,3 439.7 ± 339.0 Green, crisp 343,6 ± 14,7 41.3 ± 15.0 Green, crisp 31.8 ± 9.8 51.0 ± 1.5 Conventional steaming 2620,7±316,4 430.7 ± 84.2 Green, crisp/hard 1610,6±1162,4 35.4 ± 4.1 Green, crisp 25.1 ± 3.4 27.7 ± 2.7 Induction cooking 18.8 ± 0.8 65.5 ± 55.7 21.1 ± 0.1 10.4 ± 12.1 Conventional cooking 20.3 ± 1.9 19.1 ± 3.8 18.6 ± 2.6 19.2 ± 2.2 Microwave (900 W) Mean ± SD: SD are calculated from 2 samples and 2 repeating injections from each sample. Table 7. Isothiocyanate in broccoli with different heating methods and time. Treatment ITC in broccoli, nmol/g (Mean ± SD)[1] Percent enzyme activity retained Texture, Small stalk Texture, flower Color Raw 3185,4 ± 17,5 100 Hard Hard Green Microwave 1000W, 1 min 3178,6 ± 53,0 99,7 Raw Partially raw Green 1000W, 2 min 231,7 ± 170,2 7,2 Crisp Firm Green 1000W, 4 min 121,2 ± 39,4 3,8 Soft Soft Green 1000W, 10 min 114,3 ± 29,9 3,6 Soft, burned Soft Green Burned 500W, 8 min 79,4 ± 32,1 2,5 Soft Soft Green, dicolor 150W, 24 min 58,0 ± 8,7 1,8 Very soft Very soft Yellow brown Induction steaming 1 min 171,5 ± 53,3 439,75 ±339,0 5,4 13,8 Crisphard Crisp Green 2 min 343,6 ± 14,7 41,3 ±15,0 10,8 1,3 Crisp Crisp Green 4 min 31,8 ± 9,8 0,9 Firm Soft Green 10 min 51,0 ± 1,5 1,6 Soft Soft Green, color loss Treatment ITC in broccoli, nmol/g (Mean ± SD)[1] Steaming 1 min 2620,7 ± 316,4 430.7 ± 84.2 2 min Percent enzyme activity retained Texture, Small stalk Texture, flower Color 82,2 13,5 Crisphard Crisp Light green 1610,6 ± 1162,4 35.4 ± 4.1 50,5 1,1 Crisp Crisp Light green 4 min 25,1 ± 3,4 0,8 Crisp Firm Green 10 min 27,7 ± 2,7 0,9 Soft Soft Green Cooking 1 min 20,3 ± 1,9 0,6 Crisp Crisp Green 2 min 19,1 ± 3,8 0,5 Crisp Firm Green 4 min 18,6 ± 2,6 0,6 Firm Soft Green 10 min 19,2 ± 2,2 0,5 Soft Soft Green Induction cooking 1 min 18,8 ± 0,87 0,5 Crisp Crisp Green 2 min 65,5 ± 55,9 2,0 Crisp Firm Green 4 min 21,1 ± 0,2 0,6 Firm Soft Green 10 min 10,4 ± 12,1 0,3 Soft Soft Green, color loss Ingemar Bjorkhem: J Clin Invest. 2002 Sep;110(6):725-30. Do oxysterols control cholesterol homeostasis? Figure 1 Primary cholesterol oxygenation reactions mediated by different cytochrome P-450 species or occurring nonenzymatically in the presence of reactive oxygen species (ROS) (43). The oxygenation of cholesterol into 25-hydroxycholesterol is catalyzed by cholesterol 25-hydroxylase, a non-heme iron protein (7). The quantitatively most important oxysterols present in human circulation are underlined. Figure 2 Roles of CYP27 and CYP46 in transport of cholesterol from extrahepatic organs to the liver. Cholesterol does not pass readily across the blood-brain barrier, but cholesterol produced in the brain can be oxidized by CYP46 to form the more soluble species 24Shydroxycholesterol. Likewise, 27-hydroxycholesterol is formed in other extrahepatic cells and contributes to the net flow of circulating oxysterols from other organs to the liver http://lipidlibrary.aocs.org/lipids/chol_der/index.htm Intermediate/ Selected methods heating study Fig. 9. 7- Keto; Regression: NS for group Univariate analysis w. Bonferroni at 0.01: *Control significantly different from: - Boiling, teflon, MW, steaming, oven *Wok gas significantly different from: none * Boiling significantly different from: Control *Teflon significantly different from: Control, MW *MW significantly different from: - Control, teflon, induction * Steaming significantly different from:Control *Induction : MW *Oven significantly different from: - Control Intermediate/ Selected methods heating study Fig.10.alpha-epoxy Stepwise regression: Group, p=0,098 (NS) Univariate analysis w. Bonferroni at 0,01: *Control significantly different from:None *Wok gas significantly different from: None *Boiling significantly different from: None *Teflon significantly different from: None *MW significantly different from: None *Steaming significantly different from: None *Induction different from: None *Oven significantly different from: None Intermediate/ Selected methods heating study Fig.11. Beta-epoxy Stepwise regression: Group, p=0,041 Univariate analysis w. Bonferroni at 0,01: *Control significantly different from: All, exp. induction *Wok gas significantly different from: Control, *Boiling significantly different from: Control * Teflon significantly different from: Control, MW * MW significantly different from: - Control, teflon, steaming, induction, oven * Steaming significantly different from: –Control, MW *Induction: MW *Oven significantly different from: - Control, MW Result first /pilot study: Chicken and oxy-cholesterol 5 • All types of heating generated much higher levels of oxy-cholesterol than was found in the raw samples. • The increase in 7- keto and 7β -OH cholesterol were ≈ 2-5 fold and 10-17 fold by boiling, induction and pan frying compared to 14-21 fold and 60-80 fold for oven and MW, respectively. Discussion, second study • The top- oxidative heating methods at + 1000 ng/g were steaming and microwave heating, at 1220,5 ng/g and 1124,8 ng/g respectively. • This was seen across all 4 subclasses of oxi-cholesterols measured and thus also for the total value. • The finding was statistically significant on both ANOVA (p= 0,002), multiple regression (p= 0,03) and univariate analysis for alpha-epoxy-cholesterol (p= 0,01 compared to several other heatings) and in univariate analysis compared to wok gas for beta-epoxy – and total cholesterol Effects of non-competitive interactions involving organic substances on nutrient bioavailability in plant foods: inhibiting factors Dietary component Food sources Phytate (myo-inositol hexaphosphate) Unrefined cereals, legumes, nuts, oil plus magnesium, calcium or seeds potassium phytate Main technical influences Binds certain cations to form insoluble complexes in gut Nutritional consequences Zn, Fe, Ca and probably Mg are poorly absorbed (Heaney et al. 1991; Sandberg et al. 1999) Soyabean protein Some varieties of soyabeans, Effect not explicable on basis of Inhibits Fe and Zn absorption in some unfermented tofu, textured vegetable phytate content but instead depends varieties. Some contain Fe as protein on variety and processing method phytoferrin, which may be highly bioavailable (Murray-Kolb et al. 2003) Polyphenols Certain cereals (red sorghum), legumes (red kidney beans, black beans, black grams), spinach, betel leaves, oregano Form insoluble complexes with Fe Inhibit non-haem-Fe absorption Some polyphenols inactivate thiamin Reduce thiamin absorption Bind certain salivary and digestive enzymes Reduce digestibility of starch, protein and lipids Beverages: tea, coffee, cocoa, red wine Enhance excretion of endogenous protein Interfere with protein digestibility (Bravo, 1998) Oxalic acid Amaranth, spinach, rhubarb, yam, taro, sweet potato, sorrel, sesame seeds, black tea Oxalates form insoluble complexes with Ca and possibly Fe Reduce absorption of Ca and possibly Fe; increase urinary Ca (Savage, 2002) Dietary fibre Unrefined cereals, legumes, nuts, oil seeds, fruits and vegetables Lignin and pectin bind bile acids Reduces absorption of fats, fatsoluble vitamins and carotenoids; effects on folate bioavailability inconsistent Pectins, psyllium and gums retain water and form viscous solutions in gastrointestinal tract Slows gastric emptying and digestion and absorption of nutrients (Gallagher & Schneeman, 2001) Dietary fibres are fermented in large intestine by microflora SCFA produced that enhance Ca solubility (Demigne et al. 1995) Sorghum, Sorghum bicolor (L.) Moench; red kidney beans, Phaseolus vulgaris; black beans, Glycine max; black gram, Phaseolus mungo; spinach, Spinacia oleracea; betel, Piper betel; oregano, Origanum vulgare; amaranth, Amaranthus edulis; rhubarb, Rheum rhaponticum; yam, Dioscorea spp.; taro, Colocasia esculenta var. antiquorum; sweet potato, Ipomoea batatas; sesame, Sesamum orietale. Effects of non-competitive interactions involving organic substances on nutrient bioavailability in plant foods: enhancing factors Dietary component Food sources Main technical influences Nutritional consequences Organic acids (citric, lactic, acetic, butyric, propionic and formic acids) Fermented milk products (e.g. May form soluble ligands with some yoghurts), vegetables, sauerkraut, soya trace minerals in the gastrointestinal sauces, fermented cereals (e.g. Tobwa) tract Ascorbic acid Citrus fruits and juices Reduces Fe3+ to more soluble Fe2+; forms Fe–ascorbate chelate Enhances non-haem-Fe absorption (Teucher et al. 2004) Other fruits: guavas, mango, papayas, kiwi, strawberries May increase stability of folate during food processing and digestion Counteracts inhibitory effect of phytate Vegetables: tomato, asparagus, Brussels sprouts, spinach etc. Enhance absorption of Zn and possibly Fe (Sandström, 1997; Teucher et al. 2004) May enhance folate bioavailability (McNulty & Pentieva, 2004) May enhance or inhibit Se absorption, depending on the chemical form (Mutanen & Mykkanen, 1985; Levander, 1987). Ascorbic acid may also enhance Cr absorption (Offenbacher, 1994) Protein Amount and type (e.g. animal protein) Enhance absorption of Zn, Fe and Cu form soluble ligands with Zn, Fe and Cu (Bjorn-Rasmussen & Hallberg, 1979; Turnlund et al.1983; Lönnerdal, 2000) Increase urinary Ca excretion (Heaney, 2000) Fat Oil seeds, nuts Products of fat digestion+bile salts solubilize fat-soluble vitamins and carotenoids in intestinal milieu Enhance absorption of fat-soluble vitamins and provitamin A carotenoids (Yeum & Russell, 2002) Guava, Psidium guajava L.; mango, Mangifera indica L.; papaya, Carica papaya; kiwi, Actinidia deliciosa; strawberry, Fragaria X ananassa; asparagus, Asparagus officinalis; spinach, Spinacia oleracea. Influence of household food processing and preparation methods on bioavailability of nutrients in plant foods Processing method Thermal processing Main technical influences Nutritional consequences Releases some vitamins from poorly-digested complexes Enhances bioavailability of vitamin B6, niacin, folate and certain carotenoids Inactivates heat-labile anti-nutritional factors (e.g. protease inhibitors, α-amylase inhibitors, lectins, thiaminases, goitrogens) Enhances digestibility of proteins and starch May degrade phytate, depending on temperature Enhances bioavailability of thiamine and I Gelatinizes starch May enhance Zn, Fe and Ca bioavailability Enhances digestibility Baking Induces Maillard browning in foods containing reducing Destroys basic essential amino acids lysine, arginine sugars and methionine Reduces protein quality and protein digestibility Boiling Reduces oxalate content Enhances Ca absorption Germination and malting Increases phytase activity via de novo synthesis or activation of endogenous phytase Induces hydrolysis of phytate and hence increases Zn, Fe, Ca, and Mg absorption Reduces polyphenol content of some legumes (e.g. Vicia faba) Enhances non-haem-Fe absorption Increases α-amylase content of cereals (e.g. sorghum and millet) Facilitates starch digestion; may increase non-haem-Fe absorption through a change in consistency Village-based milling or home pounding Reduces phytate content of cereals with phytate Enhances bioavailability of Zn, Fe, and Ca, although localized in outer aleurone layer (rice, wheat, sorghum) mineral content simultaneously reduced or in germ (maize) Microbial fermentation Induces hydrolysis of phytate by microbial phytase Enhances bioavailability of Zn, Fe and Ca Increases content of organic acids May form soluble ligands with non-haem-Fe and Zn, and enhance bioavailability Microbial enzymes may destroy protein inhibitors that May improve protein quality in maize, legumes, interfere with N digestibility groundnuts and pumpkin and millet seeds Sorghum, Sorghum bicolor (L.) Moench; millet, Achnatherum hymenoides; groundnut, Apios americana Medic.; pumpkin, Cucurbita Pepo.
