Effect of edible active coatings on quality of potato (Solanum tuberosum L.) strips after the frying process

Abstract

The present study evaluated the effect of active coverings based on gum arabic incorporated with protein hydrolysates and/or citric acid on the characteristics of fried potato (Solanum tuberosum L.) chips. After the minimum processing and whitening, different coatings were applied to the potatoes: control (without coating); 5% (w/v) gum arabic and 2% (w/v) protein hydrolysate with 10% degree of hydrolysis (DH); 5% (w/v) gum arabic and 2% (w/v) protein hydrolysate with 20% DH; 5% (w/v) gum arabic and 2% (w/v) citric acid. Afterwards, the chips were vacuum-packed and stored at 4 °C. The different treatments were evaluated at time zero, 3, 5, 7 and 10 days of storage: in natura for total aerobic mesophiles, moulds and yeasts, and thermotolerant coliforms; and characterised for colour (L*, a*, b*), texture, moisture and lipids after frying at 180 °C for 5 min. The evaluated samples did not present thermotolerant coliforms (<0.03 MPN/g). Furthermore, the use of citric acid inhibited moulds and yeasts and delayed the multiplication of total aerobic mesophiles. Luminosity (L*) was significantly reduced in the control treatment. Treatments with 5% (w/v) gum arabic and 2% (w/v) protein hydrolysate (10% and 20% DH, respectively) showed greater redness (a*) and blueness (b*) relative to the control. Applying protein hydrolysate-containing coatings to French fries led to lowered firmness, and reduced moisture and lipid contents at the end of storage. Thus, the coatings with added protein hydrolysates show a promising application in producing fried potato chips with reduced oil content.