Prevention of color formation during the production of white sugar

Abstract

Do promjene boje tijekom prerade šećerne repe dolazi se na dva načina: enzimski i neenzimski. Enzimsko posmeđivanje odvija se odmah nakon rezanja repe, pri čemu u kontakt dolaze enzim (polifenol-oksidaza), kisik iz zraka i supstrat (monofenoli ili orto-difenoli), pri čemu nastaju orto-kinoni, a kao krajnji proizvodi nastaju melanini. Neenzimskim putem nastaju tamno obojeni produkti, prije svega u Maillardovim reakcijama (reakcija reducirajućih šećera i amino spojeva) i reakcijama degradacije šećera katalizirane kiselinama ili lužinama i pri visokim temperaturama. Na boju soka, tijekom prerade šećerne repe, kao i boju samoga šećera, može se, manje ili više uspješno, utjecati primjenom različitih sredstava, a jedan je od najčešće korištenih sumporov dioksid. Cilj je ovoga rada utvrditi utjecaj dodatka sumporovog dioksida na sprječavanje promjene boje soka tijekom prerade šećerne repe, a time i na boju šećera te na udio navedenog spoja u šećeru kao i promjenu udjela tijekom skladištenja bijelog šećera. U tu svrhu, provedeno je praćenje promjene boje soka i šećera (otopina i kristal) ovisno o dodatku SO2 te udjelu SO2 u šećeru odmah nakon proizvodnje i nakon godine dana skladištenja šećera. U istraživanju su korištene standardne ICUMSA (eng. International Commission for Uniform Methods of Sugar Analysis) metode.The change in color during sugar beet processing comes in two ways: enzymatic and non-enzymatic. Enzymatic browning takes place immediately after cutting beet, wherein the enzyme (polyphenol oxidase), oxygen from the air and the substrate (monophenols or ortho-diphenols) come into contact, creating an ortho-quinones, and the final products formed melanin. Non-enzymatic browning generated dark colored products, primarily in the Maillard reactions (reactions of reducing sugars and amino compounds) and reactions of sugar degradation catalysed by acids or alkalis at high temperatures. On the color of juice during the processing of sugar beet, as well as on color of sugar, can be, more or less successfully influenced with application of different agents, where one of the most commonly used is sulfur dioxide. The aim of this study was to determine the effect of the addition of sulfur dioxide to prevent color changes of juice during the sugar beet processing, and thus the color of the sugar, and the proportion of this compound in the sugar as well as the change in its ratio during storage of white sugar. For this purpose, the monitoring of color changes of juice and sugar (solution and crystal), depending on the addition of SO2, and SO2 proportion in the sugar immediately after manufacture and after one year of storage sugars, was conducted. In the study standard ICUMSA (eng. International Commission for Uniform Methods of Sugar Analysis) methods were used