Evaluation of chromium fortified- parboiled rice coated with herbal extracts: resistant starch and glycemic index

The burden of diabetes has been increasing globally, particularly in developing countries, included Indonesia. Diet of low glycemic index (GI) foods will assist the diabetics in preventing and controlling the diabetes mellitus. Some nutrients that have been proven to improve insulin sensitivity include Cr and polyphenol found in cinnamon, pandan and bay leaf. This research aimed to evaluate content of resistant starch, and glycemic index of Cr - fortified - parboiled rice (Cr-PR) coated with herbal extracts. Variety of unhulled rice and forticant used in the experiment were Ciherang and CrCl3, respectively. Three herbal extracts used were cinnamon bark powder, pandan leaf and bay leaf with concentrations of 1, 2, and 3% of CrPR, respectively. Resistant starch (RS) content was determined by enzymatic process through glucooxydase method. Testing of the GI was conducted on 18 non-diabetic volunteers. After an overnight fast, every 2 volunteers were asked to consume 1 type of cooked rice sample from the 9 products produced and afterwards, 3 volunteers who had overnight fasts each were asked to drink 250 ml of water containing 50g glucose (as a food reference). The number of samples eaten is equivalent to 50 g of glucose. RS content of Cr-PR coated with herbal extracts ranged between 8.27 – 8.84% (dry weight). Cr-PR coated with a herbal extract type of 3% had higher RS levels than the ones with herbal extracts of 6% and 9% (P <0.05). The highest RS content (8.84%) was attained by the rice which was coated with 3% cinnamon extract of 3%. The rice’s GI ranged 29 - 40. The lowest GI (29-30) was attained by the Cr-PR coated with cinnamon extract of 6-9% The low GI of Cr-PR may be more influenced by the potential of polyphenolic compounds in the herbal extract than its RS levels.