The impact of freeze drying on the rehydration and enzymatic browning of the avocado variety Hass (Persea americana Mill.)

Abstract

In 2021, Colombia produced 214,700 t of Hass avocado, representing 32.46% of the country’s total avocado production, with 96,358 t (44%) exported. Dehydration allows food preservation, whereas freeze-drying does not affect the avocado’s organoleptic features, except for its texture. The Hass avocado variety was freeze-dried at different temperatures (-20 °C, -80 °C) and freezing times (6, 12, 18 h). Enzymatic Activity (EA) and rehydration properties, such as Hydration Kinetics (HK) and Water Retention Capacity (WRC), were analysed as response variables. Hydration kinetics was assessed in different immersion mediums at 20 °C, 40 °C, 60 °C, and 80 °C. Analysis of variance was performed to evaluate both the WRC and the EA. The treatments achieved a maximum moisture content of 3.45 ± 0.84%. The maximum HK value was reached into 6 hours of freezing at -20 °C and -80 °C. The Vmax for EA occurred at -20 °C for 6 h. Freeze-drying at -20 °C and 18 h resulted in the lowest EA value (0.000742 mmol.s-1), compared to the blank.