Effects of Chemical and Enzymatic Modifications on Starch–Stearic Acid Complex Formation

Abstract

Debranched unacetylated and acetylated potato starches with two degrees of substitution, 0.041 (low) and 0.078 (high), combined with or without β-amylase hydrolysis were prepared to form soluble and insoluble complexes with stearic acid. The effects of modifications on the complexation, thermal properties, and X-ray patterns of soluble and insoluble complexes were investigated. Acetylation decreased the recovery of insoluble complexes but increased that of soluble complexes. Low acetylated, β-amylase-treated starch had a significantly increased amount of complexed stearic acid (123.1 mg/g) for insoluble complexes; high acetylated, β-amylase-treated starch had the highest complexed stearic acid (61.2 mg/g) for the soluble complexes. The melting temperature of the complexes decreased with acetylation. All β-amylase-treated acetylated complexes displayed the V-type diffraction pattern with peaks at 2θ = 7.4°, 12.9°, and 20°. These results suggest that starch can be modified by acetylation, debranching, and/or β-amylase to produce significant quantities of soluble starch-stearic acid complexes.

Effects of enzymatic modifications and botanical source on starch–stearic acid complex formation

“…An additional β‐amylase hydrolysis was used in some of the debranched starch to reduce the molecular mass as described by Arijaje et al . After the debranching, the starch slurry was adjusted to pH 6.5 with 0.5 M NaOH and incubated with 75 µL of β‐amylase at 40°C for 4 h. The enzymatic reaction was terminated by boiling for 15 min, and the β‐amylase‐treated starch was recovered as previously described for the debranched starches.…”

“…The complexed stearic acid was analyzed according to the method described by Arijaje et al . Complex (100 mg) was mixed with 10 mL of 1 M HCl and incubated in a boiling water bath with continuous stirring for 1 h. The mixture was cooled and added with 10 mL hexane, and rotated on the rotary shaker for 2 h. Two milliliter of the recovered hexane layer containing the extracted stearic acid was added with 1 mL of boron trifluoride methanol to convert stearic acid to stearic acid methyl esters.…”

Effect of Acetylation and Beta‐Amylase Treatment on Complexation of Debranched Starch with Naringenin

“…A noticeable decrease in the amount of complexed fenchone was observed for acetylated amylose with a DS 0.43 and greater, presumably because of the destabilization of the helical conformation by the acetylation and an increased steric hindrance. Recently Arijaje et al and Arijaje and Wang demonstrated that acetylation and enzymatic modification of starch increased complex formation of starch with stearic, oleic, and linoleic acids. The formation of soluble complexes between debranched starch with stearic acid increased by 8.3% when starch was acetylated, and increased by 154–245% when the DP was reduced by β‐amylase.…”

“…In general, the recovery of insoluble complexes for these fatty acids decreased 23–52% as acetylation was combined with DP reduction. The amount of complexed fatty acids increased as the starch was acetylated and debranched …”

“…Although β‐cyclodextrin has been employed to improve naringenin solubility, little work has been done on complexation of starch with naringenin. Potato and Hylon VII starches were selected to study naringenin complexation because both display a B‐type X‐ray diffraction pattern with a greater proportion of chains with longer degree of polymerization (DP), which were suggested to have a greater complexing capability . Therefore, the objective of this study was to investigate the effect of acetylation and DP reduction on Hylon VII and potato starch for their complexing capability with naringenin.…”