Developing radio frequency (RF) heating protocol in packed tofu processing by computer simulation.

Area of Science:

• Food Science and Technology
• Materials Science
• Process Engineering

Background:

• Conventional packed tofu production involves reheating soymilk and coagulant in sealed containers.
• This study explores radio frequency (RF) heating as an alternative to conventional methods for soymilk reheating in packed tofu production.

Purpose of the Study:

• To investigate the feasibility of using RF heating for packed tofu production.
• To evaluate the impact of RF heating on soymilk properties and packed tofu quality.

Main Methods:

• Determined dielectric, thermal, and rheological properties of soymilk.
• Developed a mathematical model to simulate RF heating and optimize packaging geometry.
• Assessed packed tofu quality using water holding capacity, texture analysis, color measurement, and scanning electron microscopy (SEM).

Main Results:

• Soymilk with Glucono-Delta-Lactone (GDL) coagulated above 60°C, with a slight reduction in the loss factor (ε″) during tofu formation.
• A cylindrical container (φ50 mm × 100 mm) was selected for optimal RF heating rate (5.9°C/min) and uniformity.
• RF-heated packed tofu exhibited enhanced hardness (up to 1.36x) and chewiness (up to 1.21x) compared to commercial samples, with a denser microstructure observed via SEM.

Conclusions:

• RF heating is a promising technology for packed tofu production, yielding improved gel strength and sensory qualities.
• The optimized RF heating process results in superior texture and microstructure in packed tofu.