Is isolating starch from the residue of annatto pigment extraction feasible?

摘要

We tested three different methods to isolate starch from the residue of annatto pigment extraction, namely water steeping (WS), acid steeping (AS), and alkaline steeping (KS), and analyzed how these methods affected the chemical composition, the antioxidant activity, and the physical characteristics of isolated materials. None of the methods afforded pure starch because they failed to remove proteins, lipids, phenolic compounds, and carotenoids efficiently; the non-removed components acted as encapsulating agents of starch granules. Because the isolated materials presented high starch content (64.6-68.7%), we designated them starchy materials. The isolation methods influenced the chemical composition, crystallinity, particle size, thermal properties, and antioxidant activity of the starchy materials. AS removed more fibers, but this method failed to remove phenolic compounds and carotenoids, to yield a starchy material with the greatest antioxidant activity and the highest crystallinity. KS solubilized more lipids, carotenoids, and proteins; promoted loss of phenolic compounds; and afforded agglomerated starch granules with larger particle size and high gelatinization enthalpy. WS impacted the bixin content of the starchy material to a lesser extent, but it led to loss of phenolic compounds. Overall, AS provided the starchy material with the best properties for application as food additive and for use in the production of films with antioxidant activity. (C) 2017 Elsevier Ltd. All rights reserved.