Bioactive compounds in corn:

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1 Bioactive compounds in corn: Impact of dry milling on carotenoid composition and bioavailability Mario Ferruzzi, PhD Department of Food Science Purdue University West Lafayette, IN

2 Food and its relation to Health Health care costs for the U.S. were ~$2.5 trillion in 2006 Pharma Food Forty percent of the U.S. population (now 300M) is expected to be obese by 2010 (CDC) Prescription drug cost continue to rise Trends in consumer belief of self determination through lifestyle and diet Driven by increase epidemiological association between specific foods and prevention of chronic disease

Fruits,Vegetables & Chronic Disease Increased fruit & vegetable intake has been associated through epidemiological studies with a decreased risk

3 Fruits,Vegetables & Chronic Disease Increased fruit & vegetable intake has been associated through epidemiological studies with a decreased risk of certain chronic disease Including: Cancer Cardiovascular disorders Diabetes Macular Degeneration Immune Function Chronic/Reoccurring Inflammation

4 Vegetables, fruit, and cancer prevention: A review Steinmetz KA, Potter JD Journal of the American Dietetic Association 96: (10) , 1039, 1996 In this review of the scientific literature on the relationship between vegetable and fruit consumption and risk of cancer, results from 206 human epidemiologic studies and 22 animal studies are summarized. The evidence for a protective effect of greater vegetable and fruit consumption is consistent for cancers of the stomach, esophagus, lung, oral cavity and pharynx, endometrium, pancreas, and colon. The types of vegetables or fruit that most often appear to be protective against cancer are raw vegetables, followed by allium vegetables, carrots, green vegetables, cruciferous vegetables, and tomatoes. Substances present in vegetables and fruit that may help protect against cancer, and their mechanisms, are also briefly reviewed; these include dithiolthiones, isothiocyanates, indole-3- carbinol, allium compounds, isoflavones, protease inhibitors, saponins, phytosterols, inositol hexaphosphate, vitamin C, D-Limonene, lutein, folic acid, beta carotene, lycopene, selenium, vitamin E, flavonoids, and dietary fiber.

5 Food Nutrient Macro & Micro Nutrients Energy Building Blocks Factors regulating metabolism Non-Nutrient Others Flavor Fiber Phytochemicals

6 Phytochemical Classes include: Natural Pigments. Carotenoids Anthocyanins Chlorophyll Betalains Simple Phenolics Phenolic Acids Monterpenes HO HO H O O OH OH OH Polyphenols Isoflavones Flavonols Flavanols Stilbenes Procyanidins HO HO O O O OH OH OH OH Thiol Compounds Isothiocyanates Glucosinylates O S H 3 C N C S

7 Phenolic acids in corn Corn is one of the richest grain sources of phenolic acids with ~260 mg/100g (dry wt) Phenolic acids exist in both free and conjugated forms O O OH Sugar OH Sugar H 3 CO HO Ferulic Acid HO P-coumaric Acid

8 Normal Biological Processes Biological Functions O 2 Oxidative ROS Stress Environmental Pollution NO 2 Ozone Cell Damage Disease

9 Phenolic Acids: Biological Activity Antioxidant Activity Extremely powerful in vitro Very little evidence in vivo Antimicrobial activity Potential prebiotic effect. These effects depend on form and concentration at specific tissues

10 Carotenoid Pigments Lipid Soluble Orange, Yellow and Red pigments common in fruits and vegetables -carotene Lycopene / Lutein and zeaxanthin OH HO

11 Carotenoids and Prevention of Chronic Disease Consumption of carotenoid rich fruits and vegetables is associated with decreased risk of several chronic diseases including: Cancer Cardiovascular disorders Age related macular degeneration. Carotenoid do possess biological activities consistent with preventative effects including: Provitamin A activity Antioxidant Modulation of cell signaling Modulation of inflammatory response.

12 Lutein/Zeaxanthin and Eye Health While lutein and zeaxanthin have no provitamin A activity they may have other beneficial effects. Diets high in lutein have been associated with a reduced risk of AMD Reviewed by Mozaffarieh et al., (2003) Reviewed by Alves-Rodrigez et al. (2004) Alves-Rodrigez et al. (2004)

13 Carotenoid composition in corn Xanthophyll carotenoid species predominate in corn. Typical carotenoid content of yellow corn ranges from 0.5 to 30 mg/kg (Kurlich et al., 1999; Panfilli et al., 2004) Biofortified grains have created increased provitamin A carotenoid levels (~11 mg/kg) (Howe et al., 2006a and 2006b) OH OH HO lutein HO zeaxanthin

14 Corn compares well to other grains SPECIES TOTAL CAROTENOIDS % XANTHOPYHLLS Maize ~87% Oats 0.36 ~97% Barley 1.21 ~95% Durum wheat 3.05 ~95% Semonila 2.69 Durum wheat germ 5.42 Soft Wheat 1.50 ~95% Flour 1.52 Soft wheat germ 5.58 Adapted from Panfilli et al., 2004

16 Delivery of physiological benefits from foods Food Product Clinical Assessment Product Adjustment Physiological Benefit Raw Material or Food Phytochemical Type & Content Target Tissue Metabolic Effect Physiological End-point Bioavailability

17 Bioavailability Proportion of a phytochemical from a meal secreted into circulation and made available for subsequent tissue uptake and metabolism

18 Impact of digestion on bioavailability Unit Operations: Fluid Flow Mixing Size Adjustment Separation Heat Transfer Mass Transfer May impact phytochemical stability, solubility and bioavailability

How are carotenoids absorbed by humans? Small Intestine CARTOTENOIDS /www.

Digestion (release) CART CART CART CART CART CART Circulation and tissue

19 How are carotenoids absorbed by humans? Small Intestine CARTOTENOIDS / 2. Micellarization (solubilization) 1. Digestion (release) CART CART CART CART CART CART Circulation and tissue distribution Lipids Dietary fat is a critical component of carotenoid absorption

20 Initial stages of absorption can be defined as Bioaccessibility Fraction of carotenoid in meal transferred from the food matrix to the continuous aqueous phase in the lumen and therefore available for uptake by the intestinal mucosa Focus is on release, stability and subsequent absorbability of phytochemical Bioaccessibility is a direct predictor of bioavailability.

21 Bioavailability is affected by many factors Carotenoid Species Lycopene<<carotenes<<xanthophylls Amount and type of fat in food/meal Full fat >reduced fat>fat free Food Processing Impact on food matrix Thermally processed > unprocessed Presence of negative effectors e.g. Fiber Other Processes?

22 Impact of corn dry milling process Corn Dry cleaning wet cleaning Tempering Degerminator Aspirate Sifting Aspirate Coarse Grits Flaking Grits Bran Germ Fine Grits Corn Meal Hominy Feed Oil Corn Flour Fractionation of both negative and positive factors

23 How does the milling process impact the final carotenoid profile; and modulate the bioavailability of carotenoids from corn?

24 Research Objective Overall objective: to determine the impact of milling processes on carotenoid content and measures of bioavailability from corn. Central Hypothesis: different milling processes will provide corn fractions with varied carotenoid profiles and relative bioaccessibility.

25 Specific Objectives Objective 1: Survey qualitative and quantitative differences in carotenoid profile in corn fractions generated through the milling process. Objective 2: Assess the impact of milling process on measures of carotenoid bioavailability from corn products.

26 Overall Project Design Collection of Corn samples 22 Raw Materials and milled fractions were collected from 3 suppliers Carotenoid Profiling HPLC Triplicate analysis Selection of fractions & model food systems Phase 1 Phase 2 In vitro bioavailability comparison

27 Corn fractions (Composite) mg caroteoids per kg corn fraction Cis BC BC AC BCX ACX Cis L/Z ZEA LUT 0.0 Yellow corn Corn Meal/Grits Corn Flour Corn Bran

28 Phase 1 Conclusions Yellow corn profile ranged from 9.1 to 12.6 mg total carotenoids per kg corn Primary carotenoids in corn and milled products include lutein and zeaxanthin followed by cryptoxanthins and small amounts of carotenes Carotenoids were well recovered through dry milling

29 Phase 1 Conclusions Dry milled fractions varied quantitatively but not qualitatively Lower levels in corn flour may result from fractionation of the endosperm during the degerming process While majority of carotenoids were associated with the endosperm components, bran appears to retain significant amounts of carotenoids Could be retention or incomplete separation of endosperm components from bran

30 From Content to Delivery OH HO

31 Phase 2: Bioaccessibility Screening Corn Milled Fractions White Meal Yellow meal Whole Grain Yellow Meal Food Matrix Variables Wet Cooked Grits Baked Muffin Extruded Puff 2- Stage in vitro digestion Carotenoid Analysis BY HPLC

32 White Meal Yellow Meal Whole Grain Yellow Meal

33 In Vitro Digestion Model for Estimating Bioaccessibility Carotenoids In Food Matrix Test * Meal Oral Phase Gastric Phase Formation of Crude emulsion * Oral Digesta Gastric Digesta Intestinal Formation of lipid micelles Phase * Intestinal Digesta Isolation of lipid micelles * Aqueous Micellar Fraction Centrifugation (Ferruzzi et al., 2006) (Walsh et al.,, 2004) (Garrett et al., 1999)

34 Bioaccessibility of carotenoids is expressed in absolute and relative terms Relative Bioaccessibility Absolute Bioaccessibility % micellarization Maize P88 30DAHB P88 50DAHB m g caro ten o id p er 100g Maize P88 50 DAHB 0 LUT ZEA Cis-L/Z AC BC cis-bc 0 LUT ZEA cis-l/z AC BC cis-bc Total

35 Final Comments and Future Direction Corn is a rich source of phytochemicals including phenolic acids and carotenoids Dry milled yellow corn products are good sources of carotenoids Milling does not appear to greatly impact carotenoid profile Experiments to assess bioaccessibility of carotenoids from dry milled fractions are ongoing with results expected in August 2007

36 Acknowledgments North American Millers Association Dr. Bruce Hamaker (Purdue University) Purdue Graduate Students: Ellie George Kean Angela Kohut

37 Thank You

Development of Nutrient Delivery Systems: Ingredients & Challenges

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