TY - JOUR
T1 - Acetylation of banana (Musa paradisiaca L.) and corn (Zea mays L.) starches using a microwave heating procedure and iodine as catalyst
T2 - II. Rheological and structural studies
AU - Sánchez-Rivera, Mirna M.
AU - Almanza-Benitez, Sirlen
AU - Bello-Perez, Luis A.
AU - Mendez-Montealvo, Guadalupe
AU - Núñez-Santiago, María C.
AU - Rodriguez-Ambriz, Sandra L.
AU - Gutierrez-Meráz, Felipe
N1 - Funding Information:
We appreciate the financial support from SIP-IPN , COFAA-IPN and EDI-IPN .
PY - 2013/2/15
Y1 - 2013/2/15
N2 - The effect of iodine concentration on the acetylation of starches with low and moderate degree of substitution (DS < 0.5) and its impact on the physicochemical feature and structural features was evaluated. The acetylated starches were prepared with 0.03 mol anhydroglucose unit, 0.12 mol of anhydride acetic, and 0.6, 0.9 or 1.4 mM of molecular iodine as catalyst in a sealed Teflon vessel using microwave heating (600 W/2 min). Pasting profile and rheological properties were obtained under steady flow; dynamic oscillatory test was used. Structural features were obtained by HPSEC-RI. In acetylated starches, DS and acetyl groups increased when the iodine concentration increased, corn starch showed higher values than banana starch. The viscosity of acetylated starches decreased relative to unmodified starches while, acetylated corn starch had lower value than acetylated banana starch. In the flow curves, a non-Newtonian pattern (shear-thinning) was shown in the pastes of native and modified starches. Storage modulus (G') and loss modulus (G") showed low dependence on frequency (G' α ω0.1; G" α ω0.2) on frequency sweep test, which is characteristic of a viscoelastic gel. Debranched native banana and corn starches presented trimodal chain-length distribution. The pattern was maintained in the acetylated starches, but with different level of short and long chains. The structural differences in native and acetylated samples explain the rheological characteristics in both starches.
AB - The effect of iodine concentration on the acetylation of starches with low and moderate degree of substitution (DS < 0.5) and its impact on the physicochemical feature and structural features was evaluated. The acetylated starches were prepared with 0.03 mol anhydroglucose unit, 0.12 mol of anhydride acetic, and 0.6, 0.9 or 1.4 mM of molecular iodine as catalyst in a sealed Teflon vessel using microwave heating (600 W/2 min). Pasting profile and rheological properties were obtained under steady flow; dynamic oscillatory test was used. Structural features were obtained by HPSEC-RI. In acetylated starches, DS and acetyl groups increased when the iodine concentration increased, corn starch showed higher values than banana starch. The viscosity of acetylated starches decreased relative to unmodified starches while, acetylated corn starch had lower value than acetylated banana starch. In the flow curves, a non-Newtonian pattern (shear-thinning) was shown in the pastes of native and modified starches. Storage modulus (G') and loss modulus (G") showed low dependence on frequency (G' α ω0.1; G" α ω0.2) on frequency sweep test, which is characteristic of a viscoelastic gel. Debranched native banana and corn starches presented trimodal chain-length distribution. The pattern was maintained in the acetylated starches, but with different level of short and long chains. The structural differences in native and acetylated samples explain the rheological characteristics in both starches.
KW - Acetylation
KW - Banana starch
KW - Chromatography
KW - Rheology
KW - Structure
UR - http://www.scopus.com/inward/record.url?scp=84869885368&partnerID=8YFLogxK
U2 - 10.1016/j.carbpol.2012.10.040
DO - 10.1016/j.carbpol.2012.10.040
M3 - Artículo
C2 - 23399154
SN - 0144-8617
VL - 92
SP - 1256
EP - 1261
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
IS - 2
ER -