SPECTROPHOTOMETRIC DETERMINATION OF STARCH IN TOMATO PRODUCTS WITH ANTHRONE REAGENT
Starch is a part of many foodstuffs and also used as func- tional nutritional supplement and it is necessary to have the method of its quantitative determination in food to confirm their quality and guaranteeing the absence of possible falsifi- cations. In domestic normative documents the standards are established only for quantitative determination of starch con- tent in dairy, meat products and animals’ feed. The purpose of the research was complex technique development for starch determination in the tomato products with anthrone reagent. Spectrophotometric method is based on hydrolysis of poly- saccharides in acidic environment to glucose, with the subse- quent dehydration to 5 hydroxymethylfurfural, which forms a green color complex product with anthrone reagent. The ad- vantages of this method are high sensitivity and also using inexpensive equipment and reagents. The aims of the study also include studying of various conditions of mono- and di- saccharides extraction and starch hydrolysis under acidic environment on model systems. Optimum conditions for ex- traction of free carbohydrates by 80 % ethanol water solutionand also hydrolysis of 5 % sulfuric acid solution within 15 minutes were offered. The results given in the research are complex technique for quantitative determination of starch in tomato products, which allows defining starch in the presence of other mono- and disaccharides, and natural dyes, present in the product, with the error, not exceeding 0.3 %.