Evaluation Of Glycemic Index Determination Method.

Abstract

The concept of glycemic index (GI) can be used to assist in the selection of foods in a healthy diet. Food containing low GI tends to lower postprandial blood glucose and insulin response. Because of the beneficial effect of GI, claims of low GI have been found in various food products. Therefore, the determination of GI value should be a concern. The most common method of testing GI is by using human subjects (in vivo) which has many steps to be evaluated. In Indonesia, there are two recommendations on GI method from FAO (1998) and BPOM (2011), however there are some differences in the points of recommendation, including the least subjects enrolled, reference food trials, and blood sampling points. The type of the reference food and the test portion are also points that need to be evaluated. Because of the in vivo method is time consuming, costly, and laborious, in order to overcome the difficulties of the method, the interest in in vitro methodology has increased. In evaluating the GI method, need to be seen whether the method has been able to classify samples by GI category. Therefore, sample from three classifications of GI is required, thus rice, wheat cookies, native arrowroot starch cookies, and HMT-modified arrowroot cookies were used. The objectives of this research were 1) to evaluate the steps in in vivo GI method based on BPOM (2011) and FAO (1998) recommendations, 2) to examine the feasibility of using 25 g AVCHO as basic portion, 3) to examine the feasibility of using white rice (Pandan Wangi) as a reference food, 4) to compare the result of GI in vivo method with predicted-GI in vitro method, 5) to understand the correlation of HMT arrowroot starch modification to the GI of product, 6) to determine GL of the product. Subjects enrolled in this research need to fulfil the inclusion criteria (healthy, 21-36 years old and BMI 18.5-24.9 kg/m2). In GI test, experiments were carried out involving three times for glucose testing and once for each sample. Glucose or samples containing 50 g or 25 g available carbohydrate were consumed within 12 minutes. Blood samples were obtained at 15, 30, 45, 60, 90, and 120 min consumption of samples. GI values were calculated from IAUC of blood glucose curve of samples and compared with that of reference food, ignoring the area below the fasting concentration. The conclusion from this research were (1) the recommendation that can be given is to have reference food trials at least twice with at least seven subjects with seven blood sampling points. (2) need a further study about the use of 25g AVCHO as the basis portion and the possibility of its GI-grouping, (3) Pandan Wangi white rice is feasible to be used as a reference food in GI test with conversion factor 0.74, (4) predicted-GI in vitro using H(90) starch hydrolysis sampling did not predict the GI value precisely as GI in vivo, (5) HMT modification did not affect GI value of product, (6) white rice is classified as high GL food and all of the cookies are classified as low GL food.