Conditioning potato tubers as an element of technology quality stabilization
At harvesting, transporting, loading and unload- ing and sorting potato tubers obtained mechanical damages. As a result of injury, the vacuole shells break and the polyphenols that are in them are oxidized by the action of oxygen in the air. Substances that are formed in this way the cause of denaturation of pro- teins and darkening of potato tubers [1]. As a result, potato consignments can contain up to 40% of prod- ucts with darkened pulp. Most of all, tubers are injured, which were stored at a lower temperature (less than 6 °C). One of the technological methods, which reduce the level of injury, is the conditioning (heating) of potatoes at elevated temperatures. It was found that increasing the temperature of tubers from 2 to 14 °C helps to reduce their level of injury from 18 to 4% [2]. The purpose of the research: development of opti- mal temperature regimes for conditioning potato tubers to stabilize their quality. Potato tubers of companies HZPC (Netherlands) and Solana (Germany) which apply to two groups of ripeness: medium-early and medium-ripe were investigated. Potato tubers of the investigated varieties were heated from 4 °C (storage temperature) to 6-24 ° C (temperature change interval - 2 ° C). After than in the potatoes determine density of tubers, the degree of darkening of pulp and the number of darkened tubers. As a result, it was found that in the group of medi- um-early varieties the optimal conditioning tempera- ture for the Red Lady variety is 8 °C, and for Satina and Mozart - 14 °C, and in the group of medi- um-ripe: 14 °C for Arosa and 18 °C for Sifra. There is a close relationship between the temperature of conditioning, the degree of pulp darkening and the number of tubers with darkened pulp. Thus, the mini- mum amount defect in quality of potatoes due to dark- ening of pulp was obtained: Satina - 5% (temperature - 16 °C), Red Lady - 4% (temperature 8 and 12 °C), Mozart - 2% (temperature 16 °C), Arosa - 6% (tem- perature 16 °C) and Sifra 3% (temperature 20 °C).