In the first chapter of this module, we learned the science behind our food and what exactly makes up our food from a molecular perspective.
So what makes up a typical zhap chye peng (mixed vegetables rice)? Rice, vegetables and meat. And what exactly are these food made up of? Carbohydrates, proteins, fats/oils and water. These are the four basic molecules that make up all of what we eat in a day.
Water is the simplest of the four basic food molecules. Despite its small size, water is the main component of many of our foods. It is also an important factor affecting the taste and texture of our food. Water molecules are polar molecules that can form hydrogen bonds both within itself and with other polar molecules, giving water the ability to dissolve polar carbohydrates and proteins, changing the behaviour of these molecules. Have you wondered why your pot of water takes so long to boil? That’s due to water’s high specific heat, which is the amount of energy required to raise its temperature by a given amount.
Fats and oils belong to the same family, with the former having a higher melting point than the latter. They are great flavour developers, as their high boiling points (as compared to water) allow for the tasty browning-reaction flavours to develop in your food. Another factor of fats that affects the flavour of our food is smoke point. The smoke point is the temperature at which a fat breaks down into visible gaseous products. One may notice that at the same temperature, different types of oils and fats produce smoke at varying speeds. This is due to the stability of the fat, with more stable fats having higher smoke points.
Carbohydrates in our food can come in the form of simple sugars and complex carbohydrates. Simple sugars, starch and glycogen are energy stores of animals and plants, while pectins and cellulose provide plants with structural support. These carbohydrates have vastly different structures, hence their varying properties and taste. For example, simple sugars like glucose give the sweet taste to our grapes, while complex sugars such as cellulose give rise to the fibrous texture of our vegetables stems.
Lastly, proteins are macromolecules consisting of amino acids as base units. Of the four food molecules, proteins are the trickiest to handle, as they are easily affected by temperature and pH. At low temperatures, proteins are inactive while at high temperatures, the proteins denature and their properties change with denaturation. For example, the reason behind egg whites turning opaque when cooked is due to the denaturation of proteins in the egg white at high heat.
All in all, these food molecules form the base of our food. The varying properties of these molecules determine the taste and texture of the food we eat.
Published by