Effect of ultrasound on quality of fresh-cut potatoes during refrigerated storage

In the industry of fresh-cut potatoes, controlling browning and delaying the loss of texture are important factors to obtain a high-quality product. The use of ultrasound can avoid these undesirable phenomena due to its power to inactivate enzymes by breaking the cell membranes because the cavitation activities and formation of free radicals. For this purpose, this study aimed to evaluate the effect of different times of contact of ultrasound (40 kHz, 200 W for 1, 5 and 10 min) on quality parameters (browning, firmness and total starch content) of fresh-cut potatoes during the product shelf life (12 days; 3 ± 1 °C) and cell microstructure. Ultrasound was applied to asterix strips (rectangular, 10 × 10 mm). Results showed that the time of sonication and storage affected significantly to the pH of the samples. Treated samples for 5 and 10 min presented the lower values of pH. No color degradation was noticed immediately after the application of treatments (Hue and Chroma). However, a slight decrease in Hue angle of fresh-cut potatoes during storage has been observed. The use of 5 min of sonication inhibited 50 % of polyphenol oxidase (PPO) activity for the first 4 days of storage. Samples submitted to 5 and 10 min of ultrasound also had maintained more uniform firmness after frying during storage time. However, the longest time of immersion (10 min) caused damage in the potato cells.7176184FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2011/20093-8; 2012/11520-