The aim of this research was evaluated some quality factors on apple slices immersed in essential oil (EO) solutions of oregano and thyme. Apple slices were immersed in different aqueous EO solutions: 100 ppm of oregano EO (T1), 100 ppm of thyme EO (T2), 75:25 ppm of oregano: thyme EO (T3), 50:50 ppm of oregano: thyme EO (T4), 25:75 ppm of oregano: thyme EO (T5), 100 ppm of ascorbic acid (T6) and sterile distilled water (T7) that was used as control. Apple slices were packed and stored at 5 degrees C. During 9 days were evaluated the pH, total soluble solids, titratable acidity, color, polyphenol oxidase activity, phenolic compounds, antioxidant activity, aerobic mesophilic bacteria and molds and yeasts. Also sensorial attributes. After 9 days of storage, apple slices dipped in treatments T1 y T3 had the lowest pH value and less browning. T1 and T5 showed the lowest total color change and this was represented in the low polyphenol oxidase activity. The EO solutions significantly increased (p < 0,05) phenolic compounds and antioxidant activity in T2, T3, T4, T5 and T6 treatments. However, this increase was drastically reduced after 9 days of storage, resulting in antioxidant activity of 32.1 and 35.2 % (from the beginning) in treatments T6 and T4, respectively. Aerobic mesophilic bacteria were inhibited during 3 days in apple slices dipped in T1 solution. After 9 days of storage apple slices dipped in T2 and T5 had the lowest bacterial load. Molds and yeasts were inhibited in treatments T1, T2, and T5. Apple slices with higher sensory acceptance by judges were treatment T4, T6 and T7 at the beginning of the storage and T4, T5, and T6 after 6 days.
