Majallah-i Chughundar-i Qand (Sep 2013)
Introduction of appropriate method for determining of sugar content in sugar beet produced under drought, salinity and normal conditions
Abstract
In polarimetric method of sugar content determination, the extract derived from 26 g of normal sugar beet brei is considered to be 23 ml which is added to 177 ml clear solution to make a total volume of 200 ml . The increased dry matter and sugar beet pulp under any type of stress and flaccid may decrease the volume of 26 g sugar beet extract from 23 ml. This study was conducted to determine the sugar content of the sugar beet produced under drought and saline conditions and also flaccid roots in the field after harvest. The studied roots were produced under normal, drought, semi-saline and saline conditions in two regions of Karaj and Isfahan in 2010. After harvest, roots were exposed to flaccidity and were tested independently as a 3×3 factorial experiment based on randomized complete block design in twelve replications. Root flaccidity factor (A) included three levels: a1- fresh root pro-duced at optimum condition with 76±1% moisture content, a2- flaccid root in about 70±1% moisture content, a3- completely flac-cid root with 65±1% moisture content, and extraction method factor (B) included three levels: b1- cold digestion extraction meth-od, b2- French method based on extract volume, and b3- hot digestion method. Sugar percentage, dry matter percentage, pulp percentage (marc), brix and electrical conductivity of all samples were measured. The results showed that root flaccidity increased the root dry matter from 24 to 32% and the pulp from 4.7 to 7.1%. No significant difference was found between conventional ex-traction with French method and hot digestion method for normal roots but differences in average saline stress (P<0.05), drought and saline stress (p<0.01) were significant. Overall, no significant difference was observed between French extraction and hot digestion methods in all conditions. No significant difference was found between conventional and French methods in the range of 24 to 27% dry matter (p<0.01). Based on the results of this study and the simplicity of cold digestion method, it is recommended to use cold digestion method for the roots with dry matter up to 27% and French method for the roots with dry matter more than 27%.
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