What is food chemistry? The study of the chemicals inside common foods and how they react.

WHy study food chemistry To understand the major components of foods: Lipids Protein Carbohydrates And the chemical changes of food composition which occur during the preparation of food So we can live healthy lives

What is Your food made out of? Basic food chemistry deals with the three primary components in food: Carbohydrates Lipids proteins

Scientists study food chemistry To develop a successful food product one needs a basic understanding on how ingredients work chemically and how they interact with each other Shelf stability Appearance Texture Taste Nutrition

Major components of food

Carbohydrates Make up a group of chemical compounds found in plant and animal cells. Contain the elements C, H and O having the general formula (CH2O)n Since this formula is essentially a combination of carbon and water these materials are called “hydrates of carbon or carbohydrates”.

Carbohydrates Carbohydrates are the primary product of plant photosynthesis, and are consumed as fuel by plants and animals. Food carbohydrates include the simple carbohydrates (sugars) and complex carbohydrates (starches and fiber).

Lipids (fats) Lipids include: Fats Oils Waxes Cholesterol In the body, fat serves as a source of energy, a thermal insulator, and a cushion around organs; and it is an important component of the cell.

Lipids (fats) In most instances, fats are from animal products – meats, milk products, eggs, and seafood Oils are from plants – nuts, olives, and seeds. We use lipids for flavor, to cook foods, and to improve the texture of foods.

Proteins Proteins are important components of food Every cell requires protein for structure and function Proteins are complex polymers composed of amino acids.

Proteins There are 20 amino acids found in the body Eight of these are essential for adults & children Nine are essential for infants, Essential means that we cannot synthesize them in large enough quantities for growth and repair of our bodies, and therefore, they must be included in our diet

Proteins Proteins consist of long chains of 100-500 amino acids that form into three-dimensional structures, their native state.

Proteins When you change the native state of the protein, you change the three-dimensional structure, which is referred to as denaturation. Some factors that cause denaturation include: Heating Acid

Example – Hot dog Fat Protein Carbohydrates Additives Water -Nutritional Mouth feel Appearance Lipid oxidation Saturated vs. unsaturated fat? Protein Nutritional Functional properties Water binding Emulsification Texture Animal vs. vegetable proteins? Carbohydrates Functional properties Starch Additives Salt Texture Antimicrobial Flavor Coloring agents Antimicrobials Antioxidants Buffers Water How much? Where is it bound? Processing and storage Loss of function Loss of nutrients Hazard development

What happens to food when you cook it? Are they all chemical changes?

Cooking =Chemical and physical changes new substances are made the texture and taste changes the process is irreversible an energy change occurs color changes

Cooking carbohydrates Starches consist of long chains of glucose (sugar) molecules Cooking provides energy (heat) to break the long chains into individual glucose (sugar) molecules The heat then aids in the breaking down of sugar into Carbon and water

Cooking Fats Liquify but do not break down during cooking as they can withstand very high temperatures.

Cooking Proteins The protein molecules change shape as a result of the heat energy they absorb. This is called denaturing and it is permanent. Denaturing causes changes in the appearance and texture of the meat and eggs when they are cooked. Changes texture and taste of the food

Cooking Prteins

Additional changes when cooking proteins Maillard Reaction: Meat turns brown when cooked Meat is red due to the protein myoglobin (not due to blood) Cooking oxidized/reacted the Iron in myoglobin turning it brown

Additional changes when cooking proteins White meat has very low levels of myoglobin so it doesn’t appear red and doesn’t turn brown when cooked.

Additional changes when cooking proteins Nitrates are added to meats to keep the red appearance.

Additional cooking substances Baking Powder: Baking powder is used for baking cakes. It contains sodium hydrogen carbonate, which breaks down when heated to form carbon dioxide gas. The carbon dioxide helps to make the cake mixture rise, so that the cakes are light and fluffy.

Additional cooking substances Here is the word equation for the reaction:

Genetically modified organisms In genetic engineering, scientists splice genetic material from plants, animals, or bacteria and insert this genetic material into the DNA of other organisms. These new organisms are called genetically modified organisms (GMOs).

Food calories The amount of energy stored in food 1 food Calorie is equal to 1 kCal or 1,ooo calories The formula: q =mcΔT q= heat/energy (calories) m= mass (g) c= specific heat of water (1 cal/g℃) ΔT= change in temperature (℃)

Example: If the mass of the water is 150 grams and the change in temperature of the water as as Doritos is burned is 50 celsius how many calories is the the Doritos? q =mcΔT q =(150g) x (1 cal/g℃) x (60C) = 7,500 calories 7,500/1000 = 7.5 food calories in 1 Doritos