Page 66 - FoodFocusThailand No.162 September 2019

SOMETHING ABOUT FOOD

Table 1 Glycemic Index and GL Score of different kinds of food from an experiment with humans (in vivo)

Food Glycemic Index (GI) Amount Consumed (grams) GI Score per One Portion
Boiled Broccoli 0 75 0.0
Tomato 38 123 1.5
Yellow Corn 55 166 61.5
Strawberry 40 152 3.6
Grape 43 92 6.5
Banana 51 118 12.2
Soybean 20 172 1.4
Kidney Bean 27 256 7
Milk 40 244 4.4
Soymilk 440 245 4.0
Source: www.doctorshealthpress.com/glycemic-index-and-load

noodles, and popcorn. The third group is a low glycemic index food (AUC) from 0-180 minutes was calculated as well. Next, Hydrolysis
(GI ≤ 55), such as high-fiber food, vegetable, and nuts. Nanri and Index (HI) was calculated from the relationship between the area
Mizoue (2014) reported that consuming food with high glycemic under curve of the samples and the area under curve of the white
index can increase the risk to develop type 2 diabetes and obesity. bread (reference sample). The estimated glycemic index (eGI) can
On the other hand, food with low glycemic index can help control be resolved from the equation, eGI = 39.71 + 0.549HI. Additionally,
the blood sugar level and stimulate insulin regulation to flow Granfeldt et al. (1992) conducted a study on the analysis to find
effectively. Thus, consuming the right amount of food with low glycemic index through in vitro method in order to predict glycemic
glycemic index can help control diabetes and lower the risk of obesity. index of samples. The equation used was eGI = 8.198 + 0.862HI.
Apart from glycemic index that is widely used for the assessment The second method is “in vivo.” This method lets healthy
on carbohydrate consumption, Glycemic Load (GL) is an important participants consume sample food in a specific amount (50 grams
index as well. Glycemic Load indicates a score of glycemic index of carbohydrate) before measuring a glucose level in the bloodstream
together with the amount of carbohydrate in food consumed. The which will then be compared with the standard example, white bread
score of GL = (GI x the amount of carbohydrate in food or glucose that has glycemic index = 100. This method is more
consumed)/100. With this GL score, consumers will be able to limit complicated than in vitro as it is an experiment with humans.
the amount of carbohydrate consumption. Therefore, in vitro method is more popular due to its quick outcome
There are three groups of GL according to the criteria: low GL and convenience.
means ≤ 10, medium GL means = 11-20, and high GL means ≥ 21. Nowadays, people pay more attention to their health. The
Each food has different GI and GL score depending on the glycemic index displayed on a product package in other countries
compositions. The examples of GI and GL score of food ingredients to inform and provide customers with an alternative choice can be
are shown in Table 1. a proof to this trend as shown in Picture 1. Thus, the knowledge
As for rice, which is the food that is considered to be the main about glycemic index and GL score are crucial for consumers to be
dietary of Asian people and important source of carbohydrate, it is able to choose to consume food that is beneficial to their health,
categorized as a high glycemic index food. However, a glycemic which could gradually make people become healthier overall.
index varies depending on a variety of rice and process it passes
through. The kind of rice that is famous among Thai people is jasmine
rice, which is high in glycemic index.
Currently, the test to analyze glycemic index can be conducted
mainly by two methods. The first method calls “in vitro.” This method
imitates the body’s digestive system in a test tube in which samples
that contain in it will be digested by an enzyme while starch’s digest
rate will be measured for the calculation of glycemic index and later
compared with the standard example, white bread.
Goñi et al. (1997) conducted an analysis to find glycemic index.
In the experiment, the samples were digested with α-Amylase and
Amyloglucosidase enzyme and the results were presented as the
amount of starch digested during different time (percentage). After
that the data was brought to create a graph that indicates the
relationship between the amount of time used to digest and the
amount of starch digested (percentage) and the area under curve

66 FOOD FOCUS THAILAND SEP 2019