If you search online, you’ll be able to find sellers for freeze dryer machines small enough to fit in a kitchen. If you’re willing to spend a few thousand on one, it’s fun to see what happens to common, everyday food when you leave it in a freeze dryer for several hours. Usually with candy, both the texture and shape are wildly different from what you started with.

Hempseed has been said to be a nutritious protein source with lower land requirements for farming than husbandry, and higher digestibility than soy proteins. The processing of hempseed to protein isolate (HPI) has several goals, one of which is prolonging shelf life. Freeze drying, along with spray drying, is commonly used in preparing powders of very low water content, reducing the rate of microbial spoilage in food products. However, for HPI specifically, what happens to the structure and nutritional content as a result of freeze and spray drying has not been thoroughly investigated. A team here aims to look into the effects of both freeze drying and spray drying on the structure, biochemistry, and functional properties of HPI.  This project is led by the Food Science Programme (Prof. Siew Young Quek) with which the Chemical & Materials Engineering has long enduring collaboration (A/Prof. Meng Wai Woo). 

What they found was that both drying methods did not significantly alter the content of amino acids, but could have disrupted structures in certain proteins. The conversion from hempseed to dried powder could improve digestibility, and they also assessed solubility, foaming and emulsion forming capacities of the dried HPI powders.

Read the article if you’re interested in more. It’s open access so you don’t need to login to view it.

– Basil

Article link:

The physicochemical properties, functionality, and digestibility of hempseed protein isolate as impacted by spray drying and freeze drying
doi.org/10.1016/j.foodchem.2023.137310