Joanna Miedzianka

Effect of pH on phosphorylation of potato protein isolate

Potato protein isolate (PPI) was phosphorylated with sodium trimetaphosphate (STMP) at ambient temperature and various reaction pH (5.2, 6.2, 8.0 and 10.5) to improve the functional properties without impairing the nutritional availability. Changes in chemical composition (total and coagulable protein content, ash and minerals content and amino acid composition), functional properties (protein solubility index, emulsifying activity and foaming capacity, water and oil absorption capacity) and phosphorus were determined. The chemical composition and functional properties of phosphorylated potato protein isolate (PP-PPI) were significantly different (p<0.05). The PP-PPI at pH 5.2 was characterised by the highest content of all amino acids, whereas, PP-PPI under alkaline conditions (pH 10.5) caused decrease in these compounds. PP-PPI at pH 8.0 had the highest oil absorption capacity, emulsion activity and foam capacity, whereas, PP-PPI at pH 10.5 had the highest WAC.

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

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.