EXPERTISE OF POTATO SNACKS BY OPTICAL MICROSCOPY, FTIR - SPECTROSCOPY, SPECTROFLUORIMETRY AND THIN LAYER CHROMATOGRAPHY

Abstract

Expertise of four samples of potato snacks with the flavours Barbecue, Ketchup, Cheese, Sour Cream and Onion has been carried out with the use of analytical physicochemical methods. It has been found that the mass fraction of moisture in the samples under study ranges 4.4 to 4.7%, and the mass fraction of chlorides does not exceed 2.5%. The mass fraction of starch, which was determined polarimetrically, varies from 66.1% (Sample 2) to 66.7% (Sample 3). The mass fraction of sugars in the potato snack samples does not exceed 1.9%. None of the samples contains foreign material and mineral impurities. The product’s physicochemical quality parameters established by the tests conform to the manufacturer’s indication that the product contains such ingredients as starch and potatoes (starch and proteins are part of potatoes), oil, maltodextrin, sugars, salt, proteins. Based on characteristic absorption bands in the composition of snacks, FTIR has allowed detecting the presence of the two main components: triglycerides of fatty acids (oils) and polysaccharides (the latter include starches and maltodextrins). Optical microscopy has revealed that the samples have a porous (cellular) structure, with pores distributed throughout the whole mass, which is typical of snacks. Heat treatment of the snacks in the course of extrusion and frying changes the structure of starch to the glassy state: only single whole starch grains are found in the samples. The dietary supplement monosodium glutamate E621 has been identified by thin-layer chromatography on chromatographic plates Sorbfil AF-A-UV. The mobile phases were mixtures of ethanol and distilled water in the ratio 7:3, and n- butanol, acetic acid, and water mixed in the ratio 3:1:1. It has been shown that the turmeric extract E100(i), a natural yellow food colourant, being adsorbed on potato snacks, can be identified in them by its own spectra of diffuse reflection and luminescence spectra, without destroying the samples.