Effect of Different Solvents on the Extraction of Phytochemicals in Colored Potatoes

Colored potatoes are an interesting alternative to the traditional, white-creamed potatoes, due to their high phytochemical content, which have been proved to have antioxidative properties. The extraction of polyphenols is highly dependent on using the appropriate solvent systems. Therefore, polyphenol extraction in colored potatoes [Vermillion Fingerling (VF);Jester Potato (JP);Magic Molly (MM);Blue Belle (BB);All Blue (AB)] using different solvents [Solvent A (24% water, 67% ethanol 9% acetic acid);Solvent B (5% acetic acid);and Solvent C (95% water, 5% acetic acid, 0.5 g sodium bisulfate)] may have significant effects on extraction efficiency and phytochemical content. Total phenolic content (TPC), Total flavonoid content (TFC), Total anthocyanin content (TAC) and antioxidant activities [Trolox Equivalent Antioxidant Capacity (TEAC) and Ferric reducing-antioxidant power (FRAP)] were determined. Solvent A extracted significantly (p < 0.05) higher TPC from BB (13.93 mg GAE/100g) compared to the other solvents. VF and JP displayed higher TFC (14.53 and 19.46 mg CE/100g, respectively) when Solvent C was utilized. VF and JP extracts with Solvent C displayed the highest FRAP value compared to Solvent B. MM displayed the highest TAC using Solvent A and C. Potato variety resulted in high variability in polyphenols content and antioxidant activity. The utilization of colored potatoes or extracts in the food industry could provide innovative products and a functional alternative to the traditional.

Effects of air movement in a hot air dryer on the drying characteristics of colored potato (Solanum tuberosum L.) using computational fluid dynamics

The flow fields of hot air in the dryer for drying colored potatoes of which characteristics are highly sensitive to the temperature were simulated using computational fluid dynamics(CFD)simulation.The local air velocity decreased as the distance from the flow inlet increased.The mass and heat transfer coefficients increased from 0.666×10^(-2) m/s to 1.711×10^(-2) m/s,and 6.555 W/(m^(2)·K)to 16.834 W/(m^(2)·K),respectively,as the air velocity increased from 0.207 m/s to 1.567 m/s at 60°C.The drying simulation model using the heat and mass transfer model made accurate predictions.The thermal properties of colored potato,such as the thermal conductivity and specific heat,decreased significantly from 0.440 W/(m·K)to 0.034 W/(m·K)and 3906.45 J/(kg·K)to 2198.52 J/(kg·K),respectively,as the moisture content decreased from 78% to 5%.With the variable thermal and physical properties,the heat transfer simulation model made accurate predictions of the hot-air drying characteristics for the colored potatoes,and the RMSE values for all cases were(1.85±0.27)℃.