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

Abstract
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 Cr-
PR, 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.