Study on physicochemical properties of catalytically oxidised starches from various botanical sources

• Published in: Food hydrocolloids Vol. 159; p. 110622
• Main Authors: Broekman, J.O.P., Piersma, W., Brinksma, Jelle, Deuss, Peter J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2025
• Subjects: Defatting; Gelatinisation; Homogeneous catalysis; Hydrogen peroxide; Starch oxidation; Structure-property relation; Defatting; Hydrogen peroxide; Starch oxidation; Gelatinisation; Structure-property relation; Homogeneous catalysis
• ISSN: 0268-005X
• DOI: 10.1016/j.foodhyd.2024.110622

Catalytic oxidation of starch with hydrogen peroxide (H2O2) as oxidant has been studied in recent years as a sustainable alternative to conventional sodium hypochlorite (NaOCl). A promising homogeneous catalyst for this is [MnIV2(μ-O)3(tmtacn)2][H2O](CH3COO)2 (Mncat, with tmtacn = 1,4,7-trimethyl-1,4,7-triazacyclononane), an earth abundant metal based catalyst that has been used for commercial industrial applications. We show in this work that oxidation of starches such as (waxy) corn, tapioca, wheat and rice is possible using 0.019 mol% Mncat (with respect to mol anhydroglucose units, or 0.007 wt% when compared to the mass of dry starch) and 1 wt% H2O2 (per dry weight starch), albeit reaching lower degrees of oxidation compared to potato starch. The reasons for the differences in oxidation efficiency and pasting properties were studied. The influence of granule size and lipid content was found to be limited, while crystallinity type and amylose content had an effect on oxidation efficiency. Finally, a unique thermal transition before gelatinisation was observed after oxidation using Mncat/H2O2 which was assigned to solubilisation of the amorphous lamellae of the granules, while the crystalline lamellae were left intact. This showed that oxidation by Mncat primarily takes place in the amorphous sections of the granule. In contrast to oxidation by NaOCl, the Mncat/H2O2 system can produce unique starches which can be heated past the gelatinisation temperature of the native starch.
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•Oxidation using [MnIV2(μ-O)3(tmtacn)2] with H2O2 is possible on various starches.•Potato starch was oxidised most compared to starches of other botanical origin.•Amylose content and crystallinity type mainly influenced oxidation efficiency.•A unique thermal transition before the main gelatinisation endotherm was found.•Amorphous lamellae could be selectively removed after oxidation.