Thermal and storage stability of color in juice and fructose syrup from sugar cane

Abstract

<span style="font-size:11.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-US">In this paper the thermal stability of the color of purified, <i>guarapo^a</i> and clarified, sugar cane juices after treatment with activated carbon and ultrafiltration was studied, and the color stability during the storage of fructose syrup made from them with <i>S. cerevisiae</i> invertase treatment, were evaluated. The results showed that the purification treatments removed up to 99% of the color juices. The remnant color of these purified juices increased with heat treatment at 100°C and 1 h duration, this increment being dependent on the type of purification treatment, the invertase treatment of the sucrose contained in them, and the pH of the juice. Syrups prepared from these purified and hydrolyzed juices had soluble solids over 50°Brix with a color of 25.44 IU for <i>guarapo</i>’s cane juice syrup and 76.33 IU for the clarified juice syrup. They showed increases in color during storage at room temperature reaching around 500 for the first and 1000 IU for the second one after 8 weeks. In refrigerated conditions the syrups showed more stability in their pH value and color. After 10 weeks of storage at 8°C, the color levels were 63.3 and 116.3 IU for <i>guarapo</i> and clarified juice syrups, respectively, with optical densities (OD) lesser than 0.050 ODU, corresponding subjectively to a light straw color.</span>