Food composition
Food is defined as any substance, solid or liquid that is consumed to provide the body with nutrients for its growth and smooth functioning. The human body is composed of at least 37 trillion cells, which all need energy from the nutrients we eat so that the body can function well. The foods we eat come mainly from plant and animal sources, which all contain a variety of nutrients. Food nutrients are largely grouped into macronutrients and micronutrients (1, 2).
Macronutrients are nutrients that the body needs in large quantities, such as proteins, carbohydrates, and fats. Micronutrients on the other hand are nutrients that the body needs only in small quantities, and they are divided into two groups: minerals and vitamins. Essential minerals include calcium, potassium, zinc, iodine, phosphorus, and magnesium and essential vitamins include vitamins A, D, E, C, B6, B12, and E (2).
Deficiencies in macronutrients and/or micronutrients can negatively affect our body cells, which will manifest in diseases that can be mild, severe, or even fatal. Protein deficiency for example can cause a severe health condition called kwashiorkor, with symptoms such as edema (swelling and puffing of the skin) and fatty liver (the accumulation of fat in liver cells). Vitamin C deficiency can cause a health condition called scurvy, with symptoms such as bleeding of the gums, severe joint or leg pains, and slow healing of wounds (3, 4).
Thus, having food to eat is not the only issue, but being able to get the nutrients in the food into our body cells is, therefore, more important. This is where cooking comes in.
Why We Cook Food
Cooking is an ancient practice involving the use of heat alone or heat, water, and other ingredients to prepare food. The cooking methods popularly used today are boiling, baking, frying, grilling, and steaming. While some methods tend to favor more nutrient retention, others tend to be more convenient and time effective and yet some others impart more aroma and taste to the food. However, whatever your preferred cooking method, cooking food comes with numerous benefits and the following are some of them.
Cooking makes it easier to eat food.
The solid tough structure of food is softened when cooked and biting through, and chewing is made easier. The chewing action is very important because it breaks down the chunks of food in smaller pieces, making it easier for them to mix well with saliva to form the bolus, which then travels down the esophagus easier to the stomach. Also reducing particle size by chewing increases the surface area for gastric acids in the stomach to further disintegrate it, a necessary process for proper digestion (5).
Cooking makes food digestion and absorption easier.
Cooking causes the unfolding of the protein matrix (protein denaturation), exposing its peptide chains for enzymes to easily break through, releasing the amino acids which are absorbed by our body cells in need. Cooking breakdowns long-chain carbohydrates, like starch into shorter chains like dextrin, which are easier to digest and absorbed (6, 7).
Cooking makes food safer to consume.
This is because cooking kills micro-organisms that may have found their way into the food either from the fields during cultivation and harvest or during transportation or storage. Food-borne pathogens like Escherichia coli, Campylobacter and Salmonella, are a serious problem to the food industry as they are responsible for many disease outbreaks. Foods eaten raw (like fruits and vegetables in salads), or undercooked are much more susceptible to being carriers of disease-causing microbes than cooked food. Cooking food to at least 165oF is advisable for ensuring microbial safety (8).
Cooking food improves taste and aroma.
When food is cooked, the sensory properties such as taste, and aroma improve making the food more palatable and desirable. Food that smells and tastes good encourages consumption and consequently its nutrient benefits (9).
Cooking increases the shelf life of foods.
Most foods keep longer when they are cooked. Cooking kills bacteria in food that would quickly multiple and spoil food even when refrigerated. A lesser bacteria load, therefore, ensures longer shelf life of the food (10). Cooking also disables certain enzymes that cause undesirable flavor changes reducing the food’s acceptability. Blanching of vegetables, for example, inactivates enzymes that propagate chemical reactions which produce a bitter or hay-like taste in vegetables (11). Besides some cooking methods like drying and baking reduce the water levels in foods. By reducing the amount of free water available in the food, microorganisms will not have sufficient water to grow and spoil food, even if they are not completely destroyed by heat (12).
Reactions that occur during cooking
Different cooking methods affect the different reactions that take place in a food. These reactions can be physical or chemical and they are dependent on both the temperature of cooking and the cooking duration.
Physical changes.
Physical changes comprise changes in the state of matter of the food. Here no new compounds are formed and as such physical changes tend to be reversible when heat is withdrawn. For example, fats are solid at room temperature, and so when heated, they melt into oils which are liquid. This is the case when you place some butter on a frying pan to cook or when you cook pork meat, which is fatty. When the heat is withdrawn, the oil solidifies after it cools (13).
Chemical changes.
A chemical change is a change in the makeup of the food. It involves the reactions of one or more compounds to form a new one due to the rearrangement of atoms. Because new products are formed during chemical changes, chemical reactions are usually irreversible. An example of chemical change is the transformation observed when an egg is boiled or fried. This solid structure that forms is the result of protein denaturation (unfolding) at higher temperatures, and it is irreversible (14).
Another chemical change that takes place in foods is the browning of foods called the Maillard reaction. The Maillard reaction is the reaction between amino acids and reducing sugars in a food in the presence of heat that results in a brown coloration of the food on the surface. The longer the heating, the more the browning.
The Maillard reaction is one of the most important reactions in foods, because it imparts desirable sensory qualities to foods, like taste, flavor, and appearance, increasing their acceptability. The Maillard reaction is responsible for the browning on the surface of cakes, cookies, grilled steaks, pork chops, lamb briskets, chicken, fish, and toasted marshmallows (15).
Want to experiment with the Maillard reaction with your kids? Check out this waffle maker that lets you turn watery batter into golden brown (and delicious) waffles shaped like cars and trucks: https://amzn.to/3LoSHww
Cooking food is very crucial to enhancing the digestion and absorption of nutrients, locked up in raw food. If these foods are not cooked, our body cells will be starved of the nutrients they need to properly function, which may result in us becoming malnourished, and disease-prone. Cooking also improves taste, flavor, food texture, and appearance, which increases the overall acceptability of foods.
REFERENCES
- Zimmer, C. (2013, October 23). How many cells are in your body? Retrieved May 18, 2022, from National Geographic website: https://www.nationalgeographic.com/science/article/how-many-cells-are-in-your-body
- Nutrition basics. (n.d.). Retrieved May 18, 2022, from Wsu.edu website: https://mynutrition.wsu.edu/nutrition-basics
- Coulthard, M. G. (2015). Oedema in kwashiorkor is caused by hypoalbuminaemia. Paediatrics and International Child Health, 35(2), 83–89. doi:10.1179/2046905514Y.0000000154
- Scurvy. (n.d.). Retrieved May 18, 2022, from nhs.uk website: https://www.nhs.uk/conditions/scurvy/
- Crunch! Chew your way to healthier eating. (n.d.). Retrieved May 18, 2022, from WebMD website: https://www.webmd.com/diet/obesity/features/crunch-chew-your-way-to-healthier-eating
- Sous vide cooking method makes beef protein more digestible. (n.d.). Retrieved May 18, 2022, from American Chemical Society website: https://www.acs.org/content/acs/en/pressroom/presspacs/2020/acs-presspac-december-9-2020/sous-vide-cooking-method-makes-beef-protein-more-digestible.html
- Wei, S., Lu, G., & Cao, H. (2017). Effects of cooking methods on starch and sugar composition of sweetpotato storage roots. PloS One, 12(8), e0182604. doi:10.1371/journal.pone.0182604
- CDC. (2022, February 22). Foods that can cause food poisoning. Retrieved May 18, 2022, from Centers for Disease Control and Prevention website: https://www.cdc.gov/foodsafety/foods-linked-illness.html
- Shi, S., Wang, X., Wu, X., & Shi, W. (2020). Effects of four cooking methods on sensory and taste quality of Portunus trituberculatus. Food Science & Nutrition, 8(2), 1115–1124. doi:10.1002/fsn3.1398
- Dar, A. H., Shams, R., Rizvi, Q. ul E. H., & Majid, I. (2020). Microwave and ohmic heating of fresh cut fruits and vegetable products. In Fresh-Cut Fruits and Vegetables (pp. 295–337). Elsevier.
- National center for home food preservation. (n.d.). Retrieved May 18, 2022, from Uga.edu website: https://nchfp.uga.edu/how/freeze/blanching.html
- Forsido, S. F., Welelaw, E., Belachew, T., & Hensel, O. (2021). Effects of storage temperature and packaging material on physico-chemical, microbial and sensory properties and shelf life of extruded composite baby food flour. Heliyon, 7(4), e06821. doi:10.1016/j.heliyon.2021.e06821
- Devi, A., & Khatkar, B. S. (2016). Physicochemical, rheological, and functional properties of fats and oils in relation to cookie quality: a review. Journal of Food Science and Technology, 53(10), 3633–3641. doi:10.1007/s13197-016-2355-0
- Ahmed, J., Ramaswamy, H. S., Alli, I., & Raghavan, V. G. S. (2007). Protein denaturation, rheology, and gelation characteristics of radio-frequency heated egg white dispersions. International Journal of Food Properties, 10(1), 145–161. doi:10.1080/10942910600986970
- Tamanna, N., & Mahmood, N. (2015). Food processing and Maillard reaction products: Effect on human health and nutrition. International Journal of Food Science, 2015, 526762. doi:10.1155/2015/526762