EDUCATION


The Science of Cooking Rice
THE SCIENCE OF

Rice Cooking

  • Rice cooking has been a part of families for at least the last century. We think we know how to cook our rice; a conventional rice cooker would have you believe that all you need to do is get the amount of water right – it’s a basic task after all.

  • Yet, the way we cook our rice affects so many aspects of this humble staple food – its taste, its colour and most of all,
    how healthy it is for us.

  • How is this true? To understand this, we’ll first need to take a look at what rice is made of.

1

What is Rice?

A look at a supermarket’s aisle will tell you that rice comes in different varieties; Wangi rice, Basmati rice, Jasmine rice – there’s enough to confuse the average shopper – but generally, they’re all made up of starch. Starch, in turn, is a carbohydrate composed of many glucose units. There are two starches that make up rice – Amylose and Amylopectin. The different types of rice contain different ratios of these two types of starches. For example, Basmati rice is higher in amylose compared to the japonica, which is the shorter, stickier medium-grain rice one usually finds in sushi.

2

Why Cooking Rice the Right Way is Essential to Healthy Living

Knowing the starch content of the rice you eat is important because the starch gets broken down into sugar by your digestive system and that sugar enters your blood stream. Obviously, how fast this happens affects your blood sugar level. Foods that increase your blood sugar level quickly and drastically aren’t good for your health; the body has to continually cope with these sudden changes so that in the long run, the body’s blood sugar level control mechanism just wears out. In fact, the glycemic index or GI is a number that characterizes how fast a type of food impacts blood sugar levels. Foods with a high GI produce sharp and sudden increases in blood sugar levels while low GI foods allow the sugar to get released into the blood stream slowly and gradually.

When it comes to rice, the its unhealthy GI is due to a higher amylopectin to amylose ratio, so the trick is to cook your rice in a way that increases the amylose to amylopectin ratio. Rice with a high amylose over amylopectin ratio can be classified as Slowly Digestible Starch or SDS. On the contrary, rice with a lower amylose content is Rapidly Digestible Starch or RDS. Correspondingly, rice that is classified as SDS has a lower GI than rice that is classified as RDS.

3

How to Cook Rice Right?

Very simply, rice is usually cooked by soaking the rice in water and then heating it up. The rice absorbs the water and expands, becoming soft and fluffy. But that’s not all there is to it. At a certain temperature in this process, the RDS will start to move out of the rice grain and dissolve in the water. This is called the gelatinization temperature of rice. If one holds the rice-water mixture at this temperature for long enough, the rice becomes low in RDS because most of the RDS is in the water. Getting rid of the water leaves one with rice that is amylose-rich; in other words, healthier rice.

4

How to Cook Rice Right Conveniently?

Knowing how to cook rice the healthy and right way is all well and good, but it does sound like a lot of work. A conventional rice cooker cooks rice by turning off its internal heating element when all the water in the pot is either boiled off or absorbed by the rice. This isn’t good because increasing the temperature above that of rice gelatinization simply breaks down the cell walls of the rice grain and allows the RDS from the water to get back into the rice.

So does that mean we use a pot of water over the stove? Well, that’s always an option but doing that requires time and patience since watching the temperature then becomes a necessity. This is why the Grayns rice cooker was invented – because convenience and health does not have to be mutually exclusive. What the Grayns rice cooker does, using its patented ‘RevoCook’ technology, in 4 simple steps, is to: