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

Abstract

Starch inclusion complexation has been shown to improve solubility of water insoluble molecules. Potato starch and Hylon VII are acetylated at two levels and then debranched alone or combined with β‐amylase hydrolysis, and its complexes with naringenin are prepared in aqueous conditions and characterized in this study. Both soluble and insoluble complexes are formed with the soluble complex present in the supernatant and the insoluble complex as the precipitate after centrifugation. The recovery of the soluble complexes and the naringenin content increased when starch is acetylated, and further increased when the β‐amylase treatment is included. The naringenin contents in both complexes from Hylon VII are significantly greater than those from potato starch regardless of treatments. The insoluble complexes comprise a greater naringenin content than the soluble counterparts for both starches. FTIR spectra and thermal properties by differential scanning calorimetry confirm the molecular interaction between starch and naringenin for both complexes. This work is the first to demonstrate that starch derivatives form complexes with naringenin, and both acetylation and the beta‐amylase treatment improve their complexation.

Effect of Hydroxypropylation and Beta‐Amylase Treatment on Complexation of Debranched Starch With Naringenin

“…Table summarizes the DS values of soluble and insoluble complexes of potato starch and Hylon VII that were debranched or debranched/β‐amylase treated. For the same treatment, soluble complex displayed a similar or greater DS compared to that of insoluble complex, agreeing with our separate study of acetylated potato and Hylon VII starches . The DS values of high HP potato starch complexes were significantly greater than those of high HP Hylon VII, which was attributed to the presence of a greater proportion of shorter chains in potato starch.…”

“…When the β‐amylase treatment was included, the molecular size distributions became narrower and peak DP of all peaks shifted to shorter retention times. A similar trend was observed in our separate study with acetylated starches . Hylon VII starches with or without β‐amylase hydrolysis displayed a larger proportion of longer DP chains ≈40–950 (Figure B and D); potato starches showed a larger proportion of shorter DP chains ≈40–140 (Figure A and C) after the same treatments.…”

“…It is hypothesized that acetyl groups were predominantly introduced in the amorphous lamella close to the branching points, whereas the hydroxypropyl groups may be present in the amorphous lamella close to the branching points as well as the amorphous regions close to the non‐reducing ends due to their different reaction conditions . Because β‐amylase cannot bypass the hydroxypropyl groups in the non‐reducing ends, the resultant starch chains comprised a greater amount of hydroxypropyl groups compared with acetylated starch in a separate study …”

“…An aliquot of 1.5 mL was transferred to a 2‐mL micro‐centrifuge tube and centrifuged at 9300 × g for 10 min. From the resulting supernatant, an aliquot of 0.5 mL was transferred to 1.5 mL screw‐capped glass vials and placed in an autosampler before injection into an HPLC system (Beckman‐Coulter, Fullerton, CA) for analysis …”

“…However, concerns remain on the toxicity and high cost of CD derivatives. In a separate study, potato and high amylose corn (Hylon VII) starches were acetylated and then debranched without or with DP reduction by β‐amylase before complexing with naringenin. The acetylation study results showed that both soluble and insoluble starch‐naringenin complexes were formed and the naringenin content in both complexes increased as result of acetylation and the enzymatic treatment.…”