‘Soft chill’ technology improves temperature control for food processors

A new way of using liquid nitrogen to control the temperature of foods while they are being processed will improve quality, even when used with the most heat-sensitive or reactive foods, according to Air Products.

As an effective refrigerant, liquid nitrogen has long been used to help control the temperature of a wide range of food products, such as meat, fish, fruit, vegetables, dairy products and sauces for ready meals, while they are being processed. It is beneficial in a number of ways: preventing the food from over-heating while it is being mixed, which could affect its appearance and quality; minimising moisture loss and limiting microbial growth. The liquid nitrogen is usually injected into the bottom of the food mix at intervals in order to keep it cool and its temperature is regulated.

For some heat-sensitive or reactive food products, however, such as dough, which contains yeast or sauces prone to foaming, Air Products has found that temperature control can be significantly improved by vaporising liquid nitrogen over the top of the mix, as well as injecting it into the mix itself. In view of this, Air Products has refined its existing Freshline LIN-IS (Liquid Nitrogen Injection Solution) so it is capable of offering either top or bottom injection as part of a tailor-made process solution.

Ann Callens, European food sector specialist at Air Products, says, “We discovered that by vaporising liquid nitrogen over the top of the foods being processed we could achieve a softer chill ideal for sensitive products such as doughs. This method of chilling can also help to reduce air bubbles in foam-sensitive products such as creamy sauces.”