Phosphorylation of Maize Starch Enhanced with High-Voltage Electrical Discharge (HVED) Instead of Thermal Treatment.

Artur Gryszkin,Tomasz Zięba,Marijana Blažić,Marijana Grec,Borislav Miličević,Đurđica Ačkar,Jurislav Babić,Antun Jozinović,Drago Šubarić

doi:10.3390/polym13193231

Abstract

The aim of this research was to explore the use of a high-voltage electrical treatment (HVED) as a substitute for heating during the phosphorylation of maize starch. Starch was treated with HVED, phosphorylated with Na2HPO4 or Na5P3O10 with and without thermal treatment and phosphorylated in combination with HVED prior to and after the chemical modification. When starch was phosphorylated with Na2HPO4, HVED was more efficient in catalyzing reaction (3.89 mg P/kg for 30 min HVED in relation to 0.43 mg P/kg for thermal treatment), whereas with Na5P3O10 similar P content was achieved as with thermal treatment (0.76 P/kg for 30 min HVED in relation to 0.86 mg P/kg). The order of HVED and chemical reactions did not have a marked effect on phosphorous content. In combination with Na2HPO4, HVED pre-treatment had a more pronounced effect on the solubility and water absorption, whereas post-treatment was favoured with Na5P3O10. Mean diameter was increased by all treatments, where HVED had a marked effect. Enthalpy of gelatinization ranged from 11.76 J/g for starch treated with Na5P3O10 and 10 min-HVED to 13.58 J/g for Na5P3O10 treated sample. G′ and G″ increased after both thermally and HVED enhanced phosphorylations, with a slightly more pronounced effect of the HVED.

Highlights

Starch is found in numerous food products, from bread to yoghurt, where it has thickening, gelling or texture improving functions
When starch was phosphorylated with Na2HPO4, high-voltage electrical discharge (HVED) was more efficient in catalyzing reaction (3.89 mg P/kg for 30 min HVED in relation to 0.43 mg P/kg for thermal treatment), whereas with Na5P3O10 similar P content was achieved as with thermal treatment (0.76 P/kg for 30 min HVED in relation to 0.86 mg P/kg)
Phosphorylation with Na2HPO4 increased the amount of P, showing that the reaction occurred, it was not significantly efficient unless thermal treatment or HVED was applied, with the major advantage of HVED treatment over the thermal treatment (2.781–3.892 g P/kg compared to 0.434 g/kg)

Summary

Introduction

Starch is found in numerous food products, from bread to yoghurt, where it has thickening, gelling or texture improving functions. Native starches often do not fulfil all the requirements for specific use in foods Most often, they are not stable enough at high temperatures, in acidic conditions, during storage, or do not gelatinise at required temperatures and do not have desired rheological properties. Starch phosphates are prepared using sodium dihydrogenphosphate, disodium hydrogenphosphate [2], sodium tripolyphosphate and/or sodium trimetaphosphate In all cases, both substituted and cross-linked starches may be obtained, depending on reaction conditions, and usually, a mixture of both products is produced. Ramadan and Sitohy [3] have recently reviewed mechanisms, properties and applications of phosphorylated starches in detail They reported reaction times from 25 min to 180 min, with temperatures from 25 ◦C to 180 ◦C and phosphorus to starch ratio 0.0004–0.190. Phosphorylated starches generally have better freeze–thaw stability and larger content of resistant starch, along with altered gelatinisation and pasting properties in relation to native counterparts

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