|dc.description.abstract||Due to the current consumer health concerns regarding processed foods, there is an increasing market interest on highly nutritious foods. One method to improve their nutritional value is to introduce health-benefiting compounds to the food matrix using technology such as vacuum impregnation. Potato chips, one of the most popular snacks in the US, lack the proper nutrition because of their high fat and carbohydrate content. The purpose of this study was to increase the nutritional value of potato chips by introducing phenolic compounds from green tea extract using two major processes: vacuum impregnation (VI) and vacuum frying (VF). The main objective was to test the feasibility of these two processes to produce potato chips enriched with antioxidants without detrimental effects to product quality.
Total phenolic content (TPC) was first measured to determine the optimal VI parameters. The potato chips were then vacuum fried at oil temperatures of 110˚C, 120˚C, and 140˚C for times ranging from 20 seconds to 12 minutes to test the thermal degradability of the antioxidants. Three different frying systems were also compared: vacuum frying (VF), dual step frying (DS), and atmospherics frying (AF).
A green tea concentration of 5.0%, vacuum time of 10 minutes, and a pressure of 600 mmHg yielded the maximum TPC of 196.11 mg GAE/100 g of dry potato. Contrary to previous findings, the TPC increased non-linearly with increasing temperature. While samples fried at 120°C showed an overall greater phenolic augmentation, at the frying times where MC < 2%, samples fried at 140°C showed the maximum TPC increase of
237.48%. The dehydration rate increased with increasing temperatures and the oil absorption with increased logarithmically increasing times.
Using optimal VI and VF parameters (140°C, 100 seconds), the 3 frying systems were compared. Samples fried using the AF system contained double the oil content as those fried using the VF or DS systems. VF had the highest percentage in TPC increase (208.88%), while AF had the lowest (163.21%). The 30-particapant panel gave the vacuum fried samples all passing scores (>5) with texture acquiring the highest average score of 6.63 ± 1.94. In conclusion, vacuum impregnation was successfully used as a precursor of vacuum frying to create potato chips with a high phenolic content.||en