Production and characterization of digestion‐resistant starch by the reaction of Neisseria polysaccharea amylosucrase

Abstract

Recombinant amylosucrase (200 U/mL) from Neisseria polysaccharea was used to produce digestion-resistant starch (RS) using 1-3% (w/v) corn starches and 0.1-0.5 M sucrose incubated at 358C for 24 h. Characterization of the obtained enzyme-modified starches was investigated. Results show that the yields of the enzyme-modified starches were inversely proportional to the original amylose contents of corn starches. After enzymatic reaction, insoluble RS contents increased by 22.3 and 20.7% from 6.9% of waxy and 7.7% of normal corn starches, respectively, using 3.0% starch as acceptor and 0.3 M sucrose as donor, while amylomaize VII showed the lowest increase (8.5%) in RS content. The crystalline polymorph of these enzyme-modified starches resulted in the B-type immediately after enzymatic reaction. The enzyme-modified starches displayed higher melting peak temperatures (85.6-100.68C) compared to their native starch counterparts (70.1-78.48C). After enzymatic reaction, pasting temperature increased in waxy (71.9 ! 77.68C) and normal corn starches (75.3 ! 80.68C), and the peak viscosity of waxy corn starches increased from 264 to 349 RVU, whereas that of normal corn starches decreased from 235 to 66 RVU.

Encapsulated amylosucrase‐treated starch with enhanced thermal stability: Preparation and susceptibility to digestion

“…However, retrogradation proceeded through the same procedures as in the enzymatic reactions. From this result, it follows that the crystallites of AS‐modified starches were the most stable of all samples and these starches had increased resistance to hydrolysis by digestive enzymes . A similar phenomenon was also observed in the encapsulated starch, even after cooking.…”

“…Therefore, as shown in Table , AS treatment decreased the proportion of short chains (DP 6–12) and increased the proportion of long chains (DP 25–36) in amylopectin molecules. This branch chain elongation permits the formation of ordered structural crystallites which may be hindered by α‐(1,6)‐linked branch points in amylose‐free waxy type starches . However, the branch chain length distribution of this amylose‐like polymer is different from real amylose because the DP of amylose ranges from 300 to 3000, depending on its origin , while that of AS‐treated starches is much shorter (Table ).…”

“…First, as the amount of enzyme increased, the proportion of long chains increased and short chains decreased in the amylopectin. These long chains can form relatively perfect crystallites, resistant to reactions with starch‐digestive enzymes .…”

High-yield enzymatic bioconversion of hydroquinone to α-arbutin, a powerful skin lightening agent, by amylosucrase

“…ASase genes from Neisseria polysaccharea, Deinococcus radiodurans, Deinococcus geothermalis (DGAS), and Alteromonas macleodii have been cloned and expressed in Escherichia coli (De Montalk et al 1999;Pizzut-Serin et al 2005;Seo et al 2008;Ha et al 2009). These functional enzymes were employed to make a variety of attractive biomaterials including amylose-like polymer, resistant starch, dendritic nanoparticles, and biologically active compounds Putaux et al 2006;Jung et al 2009;Seo et al 2009a;Ryu et al 2010;Cho et al 2011).…”

Effects of temperature‐cycled retrogradation on properties of amylosucrase‐treated waxy corn starch

“…The AS-treated starch exhibited a B-type X-ray diffraction pattern, and its relative crystallinity was 34.2%. Some of the branch chains elongated by AS behaved like amylose and tended to form double helices, which led to the crystalline structures in the AStreated starch (Ryu et al, 2010). Also, the aggregation of the plenty long branch chains enhanced the probability of stable crystallite reformation, thus increasing the proportion of crystallites in the AS-treated starch.…”