Food categories and composition information

1. Food categories and composition information • 14 categories defined by USDA as “commodities” • red meat, poultry, fish/shellfish, eggs, dairy, beverage milks, fats/oils, fruits, vegetables, peanuts/tree nuts, flour/cereal products, caloric sweeteners, coffee, cocoa • these include some processed foods • Food Guide Pyramid (1992) defined 6 categories from a nutritional pov – now 5 with MyPlate (2011) • Bread, cereal, rice, pasta (grains) • Fruit group • Vegetable group • Milk, yogurt, & cheese group (dairy) • Meat, poultry, fish, beans, eggs & nuts group (protein) • Fats, oils & sweets (no recommendation)

2. Food Guide Pyramid (1992)

3. New for 2011 at: http://www.choosemyplate.gov/food-groups/ New nutritional guidelines: five categories recommended for balanced daily consumption Can click on each category for description of what’s included, how much to eat, health/nutritional benefits

4. Where to find composition information • Composition of recognized nutrients in a given food/beverage can be found in USDA National Nutrient Database http://www.nal.usda.gov/fnic/foodcomp/search/ • To search the content of specific constituent across many foods, access nutrient lists at: http://www.ars.usda.gov/Services/docs.htm?docid=22114 • Databases on certain foods like flavonoids that are extensively researched are re-released periodically: http://www.ars.usda.gov/Services/docs.htm?docid=6231 • Manufactured products are required to use “Nutrition Facts” labeling • Data given per serving • Total fat, carbohydrate, protein, cholesterol, sodium, vitamins & minerals by weight & RDA • May list other constituents but not a complete list

5. Where to find composition information • Searchable nutrition facts database for produce and products at http://www.nutritiondata.com/ • For more specific information on phytochemical composition • USDA databases (recognized nutrients) • Scientific literature (all phytochemicals) • AGRICOLA database (link from UMD library site), can search National Agricultural Library • Scifinder Scholar database – searches CAS online for chemistry literature • Pubmed – studies on health/nutrition • Journal of Agricultural and Food Chemistry

6. Nutritional & Health Studies and Industry News • Nutraingredients-USA: nutrition & supplements news (http://www.nutraingredients-usa.com) • Food Navigator: food & beverage news Europe(http://www.foodnavigator.com/) USA (http://www.foodnavigator-usa.com/) • Can search by topic, ingredient, health conditions

7. 2 slices Domino’s deep-dish cheese pizza, as reported by NutritionData.com

8. A word about organic foods • Certification requirements and farming practices vary worldwide but generally • Grown without synthetic pesticides/herbicides or fertilizers • Processed without irradiation or “chemical” food additives • Not genetically modified • For animal products, pesticide-free feed and no antibiotics or growth hormones

9. But are organic foods better for you? • 2012 study: Smith-Spangler, et al, Annals of Internal Medicine 157: 348-366 • Meta-analysis of 17 human and 223 studies of nutrient & contaminant levels in foods between 1966 and 2011 • Conclusion: published literature lacks strong evidence that organic foods are significantly more nutritious, but they may reduce exposure to pesticide residues and antibiotic-resistant bacteria.

10. Natural food constituents classified by chemistry & physiological roles • Carbohydrates – energy storage • Lipids (fat/oil) – energy & structural • Amino acids and proteins – structural & regulatory • Lipoproteins, glycoproteins, etc…specialized roles • Water • Vitamins and co-factors - catalysis • Minerals • Plant secondary metabolites or “phytochemicals” • Roles in plants are many – defense, propagation • Can be classified into subcategories based on biosynthetic pathway and structure • structural similarities exist among members of a genus (e.g. Vaccinium berries)

11. Cereals, grains • Corn, rice, wheat, barley, rye, oats, millet, sorghum, etc • Kernels (seeds) used (endosperm, bran & germ) • http://www.choosemyplate.gov/food-groups/grains.html • Contain primarily carbohydrates • simple sugars • disaccharides • polysaccharides: amylose/amylopectin (starch) and cellulose (undigestible = fiber) • Fiber may be insoluble or soluble in water, structurally complex molecules • Ratio of simple:complex carbs varies • Protein, fat and mineral content varies • Vitamins/minerals may be added back if lost in processing • Plant proteins are generally deficient in lysine & methionine from: Murano, P. “Understanding Food Science and Technology”, Wadsworth, 2003.

12. Essential amino acids • Histidine • Isoleucine • Leucine • Lysine • Methionine • Phenylalanine • Threonine • Tryptophan • Valine Cannot be synthesized by human body, therefore must be included in diet “Complete proteins” Body doesn’t store a.a.’s to a great extent, needs constant supply from: Murano, P. “Understanding Food Science and Technology”, Wadsworth, 2003.

13. Meat, poultry & seafood • It’s got a lot of protein and saturated fat but it can be tasty  • Furnishes all of essential amino acids • B vitamins, iron & other minerals too. • Seafood is a bit more interesting from a health p.o.v. due to omega-3 fatty acid content in some fish…stay tuned! from: Murano, P. “Understanding Food Science and Technology”, Wadsworth, 2003.

14. Fruits & vegetables • What’s the difference? Sugar content? • Botanically speaking, a fruit is the ripened ovary of a plant, contains the seeds • A vegetable is any other edible plant part: leaf, shoot, root, tuber, bulb, flower or stem • Tomatoes & squash are fruit! • Composed mainly of water, carbohydrates, but high in vitamin content (esp. A & C) • Secondary metabolite/phytochemical content is diverse • USDA website lists categories of fruits and vegetables, some health benefits • http://www.choosemyplate.gov/food-groups/vegetables.html • http://www.choosemyplate.gov/food-groups/fruits.html from: Murano, P. “Understanding Food Science and Technology”, Wadsworth, 2003.

15. Legumes & nuts • Legumes are edible seeds, pods of certain flowering plants • Mainly from families Leguminosae, Fabaceae • Beans, lentils, soybeans, peas, peanuts • Tree nuts • Are actually fruits • Include almonds, walnuts, pecans, macadamias, etc. from various families • Both legumes and nuts • Have a high protein content compared to other plant-based foods (common nuts range from 8-38 g protein/cup) • Legumes are deficient in lysine • Carbohydrate composition may contain substantial fiber • Good source of minerals • Nuts are higher in fat, but mainly unsaturated from: Murano, P. “Understanding Food Science and Technology”, Wadsworth, 2003.

16. Dairy products • Derived primarily from cow’s milk but some other sources as well • Whole milk composition = 88% water, 3.3% protein, 3.3% fat, 4.7% carbs • pH = 6.6, high calcium content • Milkfats primarily saturated but contain fat-soluble vitamins A,D,E,K • Major carb = lactose • intolerance caused by lactase deficiency • Major proteins = casein & whey • casein is coagulated out as curd by lowering milk pH to 4.6 with rennin, an enzyme used in cheesemaking • whey proteins can be pptd out by heat, isolated by filtration • whey used as supplement and gelling agent from: Murano, P. “Understanding Food Science and Technology”, Wadsworth, 2003.

17. Beverages • No one category • Main ingredient is water • Alcohol • Sweeteners • sucrose, high fructose corn syrup, artificial • o Brix = wt % sucrose • (g sucrose/100 g sample) • measured by refractometry • flavor depends on Brix:acid ratio • Nutrients? • Phytochemicals? Water content of selected beverages Club soda 100% Iced tea 100% Light beer 95% Beer 92% Cola 89% Orange juice 88% Red wine 88% Vodka (90 proof) 62% From Murano, Understanding Food Science & Technology (2003). from: Murano, P. “Understanding Food Science and Technology”, Wadsworth, 2003.