Impact of Drying Process on Grindability and Physicochemical Properties of Celery

Area of Science:

• Food Science and Technology
• Agricultural Engineering

Background:

• Celery stems are a valuable source of nutrients and bioactive compounds.
• Optimizing drying methods is crucial for preserving celery's quality and functionality.

Purpose of the Study:

• To compare the effects of freeze drying, vacuum drying, convection drying, and convection-microwave drying on celery stem properties.
• To analyze the impact of drying on drying kinetics, physicochemical properties, and grindability.
• To determine the optimal drying conditions for high-quality dried celery.

Main Methods:

• Celery stems were dried using freeze drying, vacuum drying, convection drying, and convection-microwave drying (50W, 100W) at 40°C, 60°C, and 80°C.
• Drying kinetics were modeled using the Page model.
• Physicochemical properties (color, antioxidant capacity, chlorophylls, carotenoids) and grindability were evaluated.
• Energy consumption during grinding was assessed.

Main Results:

• Convection-microwave drying significantly reduced drying time, while freeze drying at 40°C resulted in the longest duration.
• Freeze drying at 40°C yielded the best quality, with minimal color change and highest retention of antioxidants, chlorophylls, and carotenoids.
• Convection-microwave drying at 100W caused the most significant changes in physicochemical properties.
• Drying method and temperature impacted grinding energy, particle size, and grinding energy index, with parameters worsening at higher temperatures.

Conclusions:

• Freeze drying at 40°C is the optimal method for preserving the quality and disintegration properties of dried celery stems.
• Drying conditions significantly influence the physicochemical attributes and processability of celery.
• Convection-microwave drying offers faster processing but compromises quality compared to freeze drying.