Elżbieta Rytel

Content of polyphenols in coloured and yellow fleshed potatoes during dices processing.

The purpose of the research was to examine the effect of the laboratory production of dried potato dice on the content of phenolic compounds in one yellow-fleshed potato variety and four blue-fleshed potatoes varieties. Coloured-flesh potato varieties were characterised by about three times higher amount of total phenolic content than traditional yellow-fleshed ones. The predominating phenolic acids in potato were chlorogenic acid and its isomers, which account about 90% of total phenolic content in tubers. The phenolic acid content decreased by 80% after peeling the blue-fleshed potatoes and by 60% after peeling the yellow variety. The dried potato dice obtained from yellow-fleshed potatoes had no content of phenolic acids but produced from colour-fleshed potatoes contained about 4% of the original phenolic content of the raw material. Chlorogenic acid amounted about 97% of total phenolic acid content, and the rest was neochlorogenic acid.

The influence of dehydrated potatoes processing on the glycoalkaloids content in coloured-fleshed potato.

The aim of this study was to determine the effect of different temperatures of blanching and pre-drying used in the laboratory production of dried potato dice on the content of glycoalkaloids in red and blue fleshed potato varieties. Studied potatoes of coloured fleshed varieties were characterised by a low glycoalkaloids content at 5.47 mg 100 g(-1). The production of dehydrated potato dice influenced on the decrease in glycoalkaloids content in potato products. The majority of these compounds were removed during the peeling (70%) and blanching process (29%). Potato dice blanched at the highest temperature (85 °C) and pre-dried at 120 °C was characterised by the lowest quantity of glycoalkaloids content, whereas the highest content of these compounds was found in dice blanched potato at the lowest temperature (65 °C) and pre-dried at 120 °C. The blanching process much influenced on the decrease in glycoalkaloids content than pre-drying process.

Improving the properties of fodder potato protein concentrate by enzymatic hydrolysis.

Protein hydrolysates of profitable properties were prepared from the fodder potato protein concentrate. The hydrolysis process was performed with the use of commercial available enzyme (Alcalase) over a 2 and 4 h incubation period. Chemical and amino acid composition as well as functional properties of resultant hydrolysates were determined. A 2 h long process occurred profitable to obtain preparations of well balanced amino acid composition as well as proved functional properties. The industrial preparation, modified within proteolytic enzyme, totally soluble (average 98%), was characterised by fivefold higher oil holding capacity (average 5.4 cm(3)/g) and much better foam capacity (more than 150%) as compared to the material underwent modification (13.00%, 2.1 cm(3)/g and 5.33%, respectively). Presented results suggested potential use of fodder potato protein not destined directly for food purposes as the suitable product for preparations characterised by high nutritive value and functional properties.

THE QUALITY OF FRIED SNACKS FORTIFIED WITH FIBER AND PROTEIN SUPPLEMENTS

There was studied the effect of fortification of extruded potato pellets, obtained with 5 and 10 % addition of wheat bran, corn bran and corn germ, applied separately and in mixtures with 3 % addition of potato protein concentrate on fat content and physical properties of snacks fried from them. The addition of wheat bran, regardless its dose, did positively influenced on snacks texture. Yet it also caused the increase in fat content and density, as well as darkening of snacks color. The use of corn bran contributed to lower values of snacks density and fat absorption, while the addition of corn germ resulted in lighter, more desired snacks color, but at the same time it brought about increased fat content and made snacks harder. There was not recorded any significant snacks diversity concerning expansion degree, regardless the kind of additive used, as well as snacks moisture. doi:10.5219/54

Content of anthocyanins and glycoalkaloids in blue-fleshed potatoes and changes in the content of α-solanine and α-chaconine during manufacture of fried and dried products

Summary In the last ten or so years, potatoes with purple or blue-flesh and derivative products, for example chips, have appeared on the European markets. The interest in this raw material and these products is increasing among both producers and consumers searching for novel and attractive choices. The anthocyanin content of the analysed potato varieties differed; a higher content of these pigments was determined in Blaue Elise var. potatoes. In blue-flesh varieties, the prevailing anthocyanins were acylated glycosides: petunidin and malvidin. The production process of French fries, chips and puree caused a decrease in the content of glycoalkaloids in semi-products and finished products, compared to the raw material. The greatest losses of α-chaconine and α-solanine were observed after tuber peeling (ca. 70%) and after frying (ca. 90%). French fries contained 3%, chips 16% and puree 17% of the initial amount of total glycoalkaloids. The losses of α-chaconine and α-solanine in the analysed semi-products and finished products were at the same level, regardless of the processing technology applied.

Acrylamide content in dried coloured-flesh potato products: Effects of drying

ABSTRACT The aim of this study was to determine the impact of the chemical composition of coloured-flesh potato tubers and different drying temperatures on acrylamide content in semi-finished and finished products. The dehydrated dice obtained after pre-drying contained around 67–190 μg/kg dry matter (dm) of acrylamide. The dice pre-dried at 120°C contained six times less acrylamide than those pre-dried at a higher temperature (160°C). Further drying of potato dice at 50°C increased the acrylamide content in the finished products by approximately 40% on average. The finished products contained 236–1539 μg/kg dm of acrylamide.