Enriched Potato Chips with Phenolic Compound of Red Beetroot
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There has been an interest in increasing the functionality of snack foods in the USA. Beetroot contain a high level of antioxidants. In this study, vacuum impregnation (VI) was used to impregnate a beetroot solution into potato slices to increase their health benefits while maintaining the same quality attributes of potato chips after frying. Potato slices were pre-treated with different concentrations of beetroot solutions (3, 5, and 7% w/w), vacuum pressures (300, 450, 600 mmHg), and vacuum and restoration times (5, 10, 15 minutes). Potato slices were evaluated in terms of impregnated liquid (IL), moisture content (MC), and total phenolic content (TPC). The optimum VI condition was 7% solution, 600 mm-Hg vacuum pressure for 10 min vacuum time and 60 min for the restoration time. Kinetic studies were performed to evaluate the effect of the process on moisture content (MC), oil content (OC), and total phenolic content (TPC) of enriched vacuum fried potato chips at different temperatures (110, 120, and 140°C). The final OC of enriched vacuum fried chips was 9.31±0.35, 11.96±0.78, and 12.12±0.81 % d.b. for frying temperatures of 110, 120, and 140°C, respectively. The higher the oil temperature, the higher the OC of the chips. The maximum TPC was 27% higher than the initial TPC of the chips fried at 140°C. The chips fried at 120°C and 110°C had a maximum TPC of only 20% and 11% higher than the initial TPC, respectively. The VI treatment with red beetroot extract improved the process by making potato chips with the same or better TPC than the raw material. The higher the temperature, the better the TPC in vacuum fried chips. In this study, the VI potato slices fried at different frying methods (vacuum (VF) at 140°C, dual-stage (DSF) at 140°C, and traditional frying (TF) at 165°C) were evaluated in terms of MC, OC, TPC, bulk and true density, porosity, diameter shrinkage, thickness expansion texture, color, and sensory analysis. The chips fried under TF had a 19% reduction in TPC after frying, while chips fried under VF and DSF had a 38% and 23% increase in TPC after frying, respectively. The VF and DSF methods contributed to the release of bound phenolic acids in the potato. The TPC released from the potato during VF and DSF might have been more stable due to the lower temperature, pressure, and frying times compared to the TF. Color a* (redness) was lower for potato chips fried under TF than the VI potato slices and chips fried under the other frying methods. The chips fried under TF lost the red pigment of the impregnated red beetroot solution, while the chips fried under VF and DSF maintained their red color. The color b* (yellowness) of chips fried under the DFS and TF were significantly higher (p < 0.05) than chips fried under VF. The texture of the chips was not significantly different (p > 0.05) among the different frying methods. All potato chips fried under different frying methods were acceptable by the consumer panelists. However, potato chips fried under VF and DSF were more acceptable than the potato chips fried under TF. In conclusion, VF at 140°C for 120 sec after enriched the potato slices with phenolic content by using VI is an alternative technology to produce healthy functional snacks with desired quality attributes.
AlMohaimeed, Samar Abdulrahman A (2017). Enriched Potato Chips with Phenolic Compound of Red Beetroot. Master's thesis, Texas A & M University. Available electronically from