THE TECHNOLOGY

Chemical and process engineering professor at University of Nottingham Malaysia Law has been working on a low-temperature, fandrying technique to safely preserve the quality and taste of food products for the past 10 years.

According to him, conventional techniques use hot air at 60°C, but the high temperature tends to damage the pigments in lemon skin and reduce the concentration of citral. He said other active ingredients, such as antioxidants, vitamin C and some bioactive compounds and nutrients could also be very sensitive to high-temperature processing.

This is where cool-air drying technology plays a vital role. He said his low-temperature preservation technique used a heat-pump system and heattransfer module to generate a low-temperature, low-humidity environment to dehydrate bio-origin products.

“This dehydration method can preserve more antioxidants and vitamins. It also removes water to prevent microorganisms from growing and producing toxins that are harmful to human health.

“To extract and test the bioactive ingredients after dehydration, we grind the lemon myrtle leaves into powder. The powder is spread over a large surface so that the process is more effective.

“An environment with the temperature of 20°C and 20 per cent humidity is optimal for removing moisture from bio-origin products, and preserve their active ingredients and nutrients, which are sensitive to high temperature.

“This technology is especially important in tropical countries such as Malaysia, where humidity is high throughout the year.

After drying the products, the air is recycled within the system and a condenser is used to extract the moisture from the air.

“This is a closed system, which safeguards the products against contamination. This

This dehydration method can preserve more antioxidants and vitamins.

It also removes water to prevent microorganisms from growing and producing toxins that are harmful to human health.