Effect of Pulsed Electric Fields and Osmotic Dehydration on the Quality of Modified-Atmosphere-Packaged Fresh-Cut and Fried Potatoes

Abstract

The aim of this research was to study the effect of osmotic dehydration (OD) and/or pulsed electric field (PEF) on the quality of MAP-packed potatoes, both as raw materials and after deep frying. Fresh-cut potato strips (from Naxos island) were osmotically dehydrated using a solution of 20% glycerol, 5% sodium chloride, and 1% ascorbic acid (wt) at a 5:1 liquid-to-food ratio at 35 °C for 120 min. OD-treated and untreated samples were packaged at MAP (0.2% O2 + 12% CO2) and stored at 4, 8, and 12 °C. Color (Browning Index, BI), texture (hardness, Fmax), sensory characteristics (including total sensory quality), and microbial stability (total aerobic and anaerobic counts, Pseudomonas, Entrobacteriaceae, and yeasts/molds) were monitored during storage. After package opening, samples were deep-fried at 180 °C for up to 8 min, and the oil content of fried samples was quantified. Sensory evaluation of raw and fried samples was conducted. Untreated fresh-cut potatoes were characterized by detrimental color degradation starting from the third day of storage at 4 °C and presented microbial growth (total viable counts: 6 log (CFU)/g) on the sixth day, whereas pre-treated potato samples retained their color and microbiological stability after 15 and 18 days of cold storage, respectively. OD pre-treatment reduced the oil uptake during frying (up to 30%).