The effect of UV-C stimulation of potato tubers and soaking of potato strips in water on density differences of intermediates for French-fry production

University of Agriculture In Krakow, ul. Balicka 116B, 30-149 Kraków, Poland

^* Corresponding author: Zygmunt.Sobol@ur.krakow.pl

Abstract

The paper describes the effect of UV-C stimulation of potato tubers and immersing of potato strips in water on differences in density of intermediate products for French-fry production. The density difference used for description of the experiment was defined as a relationship between the post-treatment density and pre-treatment density. The study was conducted on tubers of the Innovator variety. The studies of density changes induced by absorption of water involved measurements of the mass of potato strips in air and in water. Potato strips measured 10 × 10 mm and 60 mm in length. The strips were cut lengthwise along the longest tuber axis set between the proximal and distal tuber end. Water absorption was investigated by immersing strips in water (1) at a temperature of 20°C for 15 min and (2) at 40°C for 20 min. In addition, the study included the group (3) where strips were blanched at a temperature of 90°C for 2 min and a control group (0) which was not immersed in water. Potato tubers were irradiated by UV-C in the following ways: (1) irradiation on one side for 30 min, (2) irradiation on both sides for 15 min each, (0) control group (no irradiation). The studies were conducted at two dates: (0) after harvest and (1) after 3-month storage. Laboratory and storage experiments were conducted in 2016-2017. The density difference was statistically significantly influenced by storage time, UV-C stimulation and immersion conditions of potato strips. The density difference increased with the increase in storage duration of tubers, immersion duration of strips, water temperature (up to starch gelification temperature) and UV-C stimulation.