TY - JOUR
T1 - Effects of palm oil on structural and in vitro digestion properties of cooked rice starches
AU - Farooq, Adil Muhammad
AU - Dhital, Sushil
AU - Li, Chao
AU - Zhang, Bin
AU - Huang, Qiang
PY - 2018/2/1
Y1 - 2018/2/1
N2 - The glycemic potency of rice depends upon the rate and extent of starch hydrolysis by pancreatic amylase and intestinal alpha-glucosidases. However, complexation of starch molecules with lipids is known to reduce the enzymic hydrolysis. In this study, we elucidated the varietal effect of rice starches on the formation of amylose-lipid complex, after cooking with palm oil, a common cooking oil. The amount of complexed lipid followed the order of black (2.5%), brown (2.5%), white (1.5%) and waxy (0.5%) rice starches. After heating with palm oil, the relative crystallinity of all the rice starches were destroyed whilst a V-type peak at 20° 2θ was increased, indicating the formation of amylose-lipid complex. This is also suggested from the DSC data where the melting enthalpy increased significantly after cooking in palm oil for all rice samples. The formation of amylose-lipid complex reduced the in vitro starch digestibility, enhancing the resistance starch content whilst decreasing the rapid and slow digestion fractions of non-waxy varieties. The rate and extent of in vitro starch hydrolysis seems to be dependent on the presence or absence of amylose fraction. With the mechanistic details, the present study suggests the applicability of palm oil addition during the rice cooking to enhance its nutritional functionality.
AB - The glycemic potency of rice depends upon the rate and extent of starch hydrolysis by pancreatic amylase and intestinal alpha-glucosidases. However, complexation of starch molecules with lipids is known to reduce the enzymic hydrolysis. In this study, we elucidated the varietal effect of rice starches on the formation of amylose-lipid complex, after cooking with palm oil, a common cooking oil. The amount of complexed lipid followed the order of black (2.5%), brown (2.5%), white (1.5%) and waxy (0.5%) rice starches. After heating with palm oil, the relative crystallinity of all the rice starches were destroyed whilst a V-type peak at 20° 2θ was increased, indicating the formation of amylose-lipid complex. This is also suggested from the DSC data where the melting enthalpy increased significantly after cooking in palm oil for all rice samples. The formation of amylose-lipid complex reduced the in vitro starch digestibility, enhancing the resistance starch content whilst decreasing the rapid and slow digestion fractions of non-waxy varieties. The rate and extent of in vitro starch hydrolysis seems to be dependent on the presence or absence of amylose fraction. With the mechanistic details, the present study suggests the applicability of palm oil addition during the rice cooking to enhance its nutritional functionality.
KW - Amylose-lipid complex
KW - In vitro starch digestibility
KW - Rice starch
UR - http://www.scopus.com/inward/record.url?scp=85030712203&partnerID=8YFLogxK
U2 - 10.1016/j.ijbiomac.2017.09.089
DO - 10.1016/j.ijbiomac.2017.09.089
M3 - Article
C2 - 28947222
AN - SCOPUS:85030712203
SN - 0141-8130
VL - 107
SP - 1080
EP - 1085
JO - International Journal of Biological Macromolecules
JF - International Journal of Biological Macromolecules
IS - Part A
ER -