Technology for processing of potato chips impregnated with red rootbeet phenolic compounds

Abstract

The objective of this study was to produce healthy snacks using vacuum impregnation (VI) and vacuum frying (VF) technology.Potato slices were pre-treated with different concentration of beetroot solution (3, 5, and 7% w/w), vacuum pressures (300 mmHg, 450 mmHg, 600 mmHg), and vacuum and restoration times (5, 10, 15 min). The optimum VI conditions were 7 w/w red-beet extract concentration solution, 600 mm Hg vacuum pressure for 10 min and 60 min of restoration time. The potato slices were vacuum fried at 110, 120, and 140 °C.Moisture loss of potato chips during vacuum frying was faster at higher temperatures and was successfully modeled with a modified equation for moisture diffusion in a flat plate. The diffusion coefficient values varied from 1.65 × 10−8to 4.99 × 10−8 for temperature ranging from 110 °C to 140 °C, respectively. The influence of the frying oil temperature on the moisture diffusion coefficient during vacuum frying was describe using an Arrhenius equation, where the pre-exponential factor (A) was 3.57 × 10−2 s−1, and the activation energy (Ea) was 4.61 × 105 J/mol for the temperature range from 110 °C to 140 °C.For the oil content, two regions (120 °C and 140 °C) were defined for the kinetic model considering that each curve presents different behaviors before and after the maximum oil content reached during frying. Chips fried at 110 °C and 120 °C had a maximum total phenolic content (TPC) of only 11% and 20% higher than the initial TPC values of the VI slices, respectively, while the TPC of slices fried at 140 °C was 27% higher.Vacuum impregnated potato slices fried were also fried using different flying methods (vacuum at 140 °C, dual stage at 140 °C, and traditional frying at 165 °C). The VI chips fried by traditional frying (TF) had 9% reduction in TPC after frying, while those fried under vacuum and dual-stage frying (DSF) had a 38% and 23% increase in TPC, respectively.Compared to the impregnated potato slices, the color of the chips fried under TF deteriorated more (higher b* value) than the chips fried under vacuum or in the DSF method. The chips fried by the TF method were harder to break than the chips fried by the other two methods.A consumer test panel found the potato chips fried under vacuum and dual-stage frying more acceptable than the potato chips fried under atmospheric pressure.Vacuum frying at 140 °C for 120 s after vacuum impregnation is a potential technology to produce healthier functional snacks with desired quality attributes.