Glycemic Index and Microstructure Evaluation of Four Cereal Grain Foods

RamyaBai, M and Wedick, N M and Shanmugam, S and Arumugam, K and Nagarajan, L and Vasudevan, K and Gunasekaran, G and Rajagopal, G and Spiegelman, D and Malik, V and Anjana, R M and Hu, F B and Unnikrishnan, R and Willett, W C and Malleshi, N G and Njelekela, M and Gimbi, D and Krishnaswamy, K and Henry, CJK and Mohan, V and Sudha, V (2019) Glycemic Index and Microstructure Evaluation of Four Cereal Grain Foods. Journal of Food Science, 84 (12). p. 3373. ISSN 0022-1147



To determine the glycemic index (GI) of selected cereals and association with their microstructure. The GI of whole grain pilaf (WGP), instant brown rice (IBR), whole maize ugali (MWU), and refined maize ugali (RMU) was assessed in a randomized trial. Fourteen healthy participants with mean age of 25 years were administered 50 g portions of available carbohydrates from glucose and various test foods after an overnight fast on separate occasions. Capillary blood samples of participants were used to measure blood glucose over 2 hr. The GI was calculated as per standard protocol. The microstructure of test foods, determined by scanning electron microscopy was evaluated to understand the measured GI values. The GI (mean ± standard error) of IBR was the highest (87.8 ± 6.8) followed by RMU (74.7 ± 6.5) and WMU (71.4 ± 5.1). WGP had medium GI (58.9 ± 5.1; P < 0.01 vs. IBR). Microstructure examination of IBR revealed disruption of bran layer and presence of fissures indicating loss of intactness of bran. Stereozoom images for WGP revealed intact bran and germ. For RMU and WMU, the grain was milled leading to loss of integrity. IBR, RMU, and WMU have high GI values, which is likely due to disruption of bran layer, endosperm modification (IBR), and loss of grain matrix (WMU, RMU). WGP has medium GI probably due to fairly intact bran and germ. PRACTICAL APPLICATION: Wholegrain or whole meal flour may not necessarily be low in glycemic index (GI; low GI < 55; medium 55 to 69 and high GI ≥70). "Ugali" a commonly consumed cereal staple food in Tanzania made from either refined or whole meal maize flour was found to be a high GI food. Intact whole grain foods, such as whole grain pilaf (mixed intact whole grains) is a healthier alternative to milled whole grains such as whole meal maize flour. Instant quick cooking brown rice exhibited a high GI, due to the processing method, suggesting that regular brown rice may be a healthier option.

Item Type:Article
Official URL/DOI:
Uncontrolled Keywords:food processing, grain matrix, microstructure, refined flour, stereozoom, whole grains
Subjects:Nutrition and Diabetes
Divisions:Department of Epidemiology
Department of Nutrition and Dietitics
ID Code:1156
Deposited By:surendar radha
Deposited On:31 Jan 2020 15:07
Last Modified:31 Jan 2020 15:07

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