How Is Food Related to Chemistry?

Atoms and combinations of atoms make up all substances, including food. Chemistry studies how atoms interact with each other and the changes that occur when that happens. When you heat food, freeze it, mix it and store it, you are making changes to the atoms in food, and that all boils down to chemistry. Food chemists are experts who study the atoms in food and how they react to change.

Food Changes

• When food is heated or frozen, the atoms in it speed up. This can cause a change in how the atoms configure themselves or combine with others. Cream is a liquid, but when it is frozen, it becomes ice cream. Solids added to it do not sink or float, they are suspended. When cream is heated, especially to boiling, it separates and forms a skim on top. Chemistry can help manipulate those changes so that they achieve a better effect, such as altering the rate of freezing to prevent large ice crystals in ice cream.

Quality and Taste

• Artificial flavors are chemical compounds that mimic the smell or taste of food. They are derived using chemistry, but also use chemistry in their combination. Food chemists also change the chemical composition of certain ingredients to help them fulfill their purpose during storage and handling. For example, the combination of milk and starch in puddings will separate over a few days, but using chemistry to modify the starch helps to prevent that from occurring, which increases the marketability and storage time of the pudding. This work helps guarantee a product's consistent taste and quality.

Preservation

• Preservatives are chemicals that chemists add to foods that, without altering their taste or texture, prevent or slow down the forming of mold and pathogens. Different preservative chemicals are used in different foods, since they react differently to different foods and each food attracts a different type of mold or pathogen. These food spoilers need certain elements such as oxygen, nitrogen, phosphorous and carbon. If they are not able to pull those elements out of the food or the packaging environment, they cannot thrive. Chemists also figure out the best way to process a food to minimize the harmful bacteria in it without changing its desirability. Pasteurization of milk involves the quick heating of milk to very high temperatures that kill bacteria but do not cause the proteins in milk to form clots.

Packaging and Preparation

• Packaging and preparation materials can affect the chemistry of food and create unsafe conditions. Tomatoes stored in aluminum or heated in aluminum pans cause leaching of aluminum into food. It is not safe to prepare foods except eggs using copper bowls due to leaching of large amounts of copper. Foods can react with plastics used for storage and promote leakage of toxins in the plastics. Certain food packaging used for storage may not hold up under freezing or heating. Many packaged foods require you to remove the packaging before microwaving because of how heat affects the packaging and leaches toxins into the food. Altering the chemical composition of the plastic can eliminate that problem, as can be seen in the microwaveable "steam" bags used for some frozen vegetables.

Pesticides and Herbicides

• Pesticides and herbicides are developed by chemists to kill pests and weeds while preventing harm to plants without leaving toxic residue. Many of these chemicals are species specific; they work for certain plant species or combat a particular insect or weed. This involves a great deal of work by chemists to find exactly the right combination and ratio of ingredients to do the job while keeping the toxicity of the product as low as possible. The product must also be producible in large quantities at a reasonable cost. These chemicals allow farms to produce more food.