TOPINAMBOUR MAIN COMPONENTS CONTENT DETERMINATION IN THE PROCESS OF STORAGE VIA ANALYTICAL AND PHYSICOCHEMICAL ANALYSIS METHODS
Authors: Samoilenko S. , Bielykh I. , Myronenko L. , Zviahintseva O. , Blyzniuk O. , Masalitina N. 
Published: January 2023

Paper is devoted to the study of topinambour's biologically active substances through analytical and physico-chemical analysis methods.

In the course of experiment,  content of inulin and vitamins in topinambour was determined, using methods of analytical chemistry, which was: inulin – 65,43 μg/100 g, vitamin C – 100,12 μg/100 g, beta-carotene – 55,26 μg/100 g.

Change in inulin mass fraction in topinambour's raw material powder during its storage at different temperatures was investigated. During seven months topinambour tubers storing at different temperature conditions, the mass fraction of inulin was larger in altered into powder and dried raw materials - 60 %, then in freezer – 50 % and the smallest mass fraction was in refrigerator – 20 %.

Сhange in ascorbic acid mass fraction by means of titrimetric analysis method was investigated. A sharp decrease of ascorbic acid content in tuber's powder was observed, it is due to vitamin inactivation under high temperatures in the process of raw materials drying. Content of ascorbic acid in cooled tubers (4 ± 2) °С to the end of shelf-life decreased by 60 %. The best results were obtained in frozen tubers (–20 ± 2) °C, content of ascorbic acid in them has changed 12–15 % compared to control sample.

Beta-carotene content was determined by photocolorimetric method according to standard methods. Content of β-carotene decreased to a level 12 % by the end of shelf life in topinambour's tuber powder. In frozen tubers (–20 ± 2) °С content of β-carotene was accompanied by a decrease in the mass fraction of β-carotene throughout whole storage period and amounted to 60 %. The best results were obtained in tubers that overwintered in soil, vitamin's mass fraction in them decreased by only 10 %.

When storing topinambour's tubers at different temperature conditions, proportion of vitamins is the highest in tubers that have overwintered in soil, then in the freezer and the lowest in the refrigerator.

Recommendations on the method of topinambour's storage with maximum preservation of biologically active substances content were given. 

Dried topinambour's tuber powder is most suitable for long-term storage with minimal loss of inulin and beta-carotene, which allows to use this powder in the production of therapeutic and prophylactic drugs. 

When stored at temperatures (–20 ± 2) °C there is a sharp decrease in nutrients in the first two months and a further decrease is very slow. Such storage is expedient if it is necessary to keep tubers for a long time. For example, in production of topinambour's preparations it is necessary to provide а plant with raw materials for the winter. 

Storage in refrigerator at a temperature of (4 ± 2) °C is advisable for a short period of time. Decrease of inulin and vitamins content is not rapid, in such conditions it can be stored for two months. In the long period, tubers wither and pathogenic microflora begins to develop on them.

The best indicators in all biologically active substances were stored in tubers that overwintered in the soil. Because the top layer in topinambour does not protect cells from decay processes, these processes are activated during digging, and tubers, that were left in the soil, continue to functionate, so cell apoptosis is not activated.