Structure and Function of Starch and Resistant Starch from Corn with Different Doses of Mutant Amylose-Extender and Floury-1 Alleles

Abstract

Four corn types with different doses of mutant amylose-extender (ae) and floury-1 (fl1) alleles, in the endosperm, including no. 1, aeaeae; no. 2, fl1fl1fl1; no. 3, aeaefl1; and no. 4,fl1fl1ae, were developed for use in making Hispanic food products with high resistant starch (RS) content. The RS percentages in the native starch (NS) of 1−4 were 55.2, 1.1, 5.7, and 1.1%, respectively. All NS were evaluated for pasting properties with a rapid viscoanalyzer (RVA) and for thermal properties with a differential scanning calorimeter (DSC). NS 1 had a low peak viscosity (PV) caused by incomplete gelatinization, whereas NS 3 had the greatest PV and breakdown of all four starch types. On the DSC, NS 2 had the lowest onset temperature and greatest enthalpy. NS 1 and 3 had similar onset and peak temperatures, both higher than those of NS 2 and 4. The gel strength of NS heated with a RVA was evaluated by using a texture analyzer immediately after RVA heating (fresh, RVA-F) and after the gel had been stored at 4 °C for 10 days (retrograded, RVA-R). NS 1 gel was watery and had the lowest strength (30 g) among starch gel types. NS 3 gel, although exhibiting syneresis, had greater gel strength than NS 2 and 4. The structures of the NS, the RS isolated from the NS (RS-NS), the RS isolated from RVA-F (RS-RVA-F), and the RS isolated from RVA-R (RS-RVA-R) were evaluated by using size exclusion chromatography. NS 1 had a greater percentage of amylose (AM) (58.3%) than the other NS (20.4−26.8%). The RS from all NS types (RS-NS) had a lower percentage of amylopectin (AP) and a greater percentage of low molecular weight (MW) AM than was present in the original NS materials. The RS-RVA-R from all starches had no AP or high MW AM. The percentages of longer chain lengths (DP 35−60) of NS were greater in 1 and 3 than in 2 and 4, and the percentages of smaller chain lengths (DP 10−20) were greater in 2 and 4 than in 1 and 3. In general, NS 3 seemed to have inherited some pasting, thermal, and structural characteristics from both NS 1 and 2, but was distinctly different from 4. Four corn types with different doses of mutant amylose-extender (ae) and floury-1 (fl1) alleles, in the endosperm, including no. 1, aeaeae; no. 2, fl1fl1fl1; no. 3, aeaefl1; and no. 4, fl1fl1ae, were developed for use in making Hispanic food products with high resistant starch (RS) content. The RS percentages in the native starch (NS) of 1-4 were 55.2, 1.1, 5.7, and 1.1%, respectively. All NS were evaluated for pasting properties with a rapid viscoanalyzer (RVA) and for thermal properties with a differential scanning calorimeter (DSC). NS 1 had a low peak viscosity (PV) caused by incomplete gelatinization, whereas NS 3 had the greatest PV and breakdown of all four starch types. On the DSC, NS 2 had the lowest onset temperature and greatest enthalpy. NS 1 and 3 had similar onset and peak temperatures, both higher than those of NS 2 and 4. The gel strength of NS heated with a RVA was evaluated by using a texture analyzer immediately after RVA heating (fresh, R...

Exotic Corn Lines with Increased Resistant Starch and Impact on Starch Thermal Characteristics

“…Amylose recrystallizes quickly upon cooling, whereas amylopectin recrystallizes more slowly; thus more amylose (%) should provide greater retrogradation (%r), which did not occur in the current study. The amount of RS3 formed, however, could vary, based on the factors just mentioned, ease of granule rupture which would reduce starch realignment, and annealing during the gelatinization process (Yao et al 2009). Both parents and progeny crosses in this study showed unusual DSC peak shapes with a large amount of tailing, thus reducing the accuracy of the %r measurement and conclusions regarding RS3.…”

Physicochemical properties, modifications and applications of starches from different botanical sources

“…The second group, RS II, consists of gelatinized starch (i.e., the starch has lost its crystalline conformation and is composed primarily of amylose); this type is very common in most starchy foods (Fuentes-Zaragoza et al, 2011). Dn the other hand, RS III is formed during starch retrogradation, which occurs after manufacturing in the presence of water, cooling and storage (Sanz et al, 2009;Yao et al, 2009). Chemical modifications to produce gelling and emulsification agents result in RS IV.…”

Resistant starch: A review of analytical protocols for determining resistant starch and of factors affecting the resistant starch content of foods

“…According to Sang, Bean, Seib, Pedersen, and Shi (2008), starch from heterowaxy sorghum (14% amylose) had the highest amount of RS (23.7%) compared to waxy sorghum starch (0% amylose; 8.4% RS) and normal sorghum starch (23.7% amylose; 17.9% RS), indicating the significance of the amylose to amylopectin ratio with respect to the RS level. In another study of four different hybrids, aeae × aeae (high amylose); fl1fl1 × fl1fl1; aeae (female) × fl1fl1 (native) and aeae (pollen) × fl1fl1 (female), starch from self pollinated aeae produced the highest amounts of RS (55.2%) compared to the other hybrids (1-6% RS) (Yao, Paez, & White, 2009). Genotypic variations influenced RS levels in thermally processed low-(23-Am), and highamylose (67-Am) pea (Pisum sativum L).…”