Fundamentals of Sea Vegetable Processing for Production of Sustainably Dried Kelp and Value-Added Extracts

Project Description

Sugar kelp is a globally important seafood and a nutritious source of dietary fibers, vitamin C, vitamin K, iron, calcium, magnesium, and iodine. Apart from dietary value, kelp is extensively cultivated for polysaccharides such as carrageenan, alginates, and fucoidan, which are used in emulsifying, food thickening, cosmetics, and the paper industry.

The quality of the extracted products and the nutrient value are highly dependent on the applied drying technique. Growing and harvesting seaweed in Maine has the potential for considerable growth beyond the current scale of operations. A bottleneck to achieving further expansion of the business is the drying process. Current drying methods depend largely on natural, solar open-air drying, which is labor intensive and can give variable results, or inefficient heated air systems. Energy efficient and reliable means of drying are needed to help the industry expand and provide a consistently high-quality product.

The objectives of this research are: to obtain the water sorption isotherm and glass transition temperature of sugar kelp (Saccharina latissima); to apply Fick’s diffusion model to the drying curves obtained by convective drying; to fit the Suzuki model of shrinkage kinetics; and to develop a COMSOL model for simulation under different drying conditions.

Results and Accomplishments

Effects of temperature, humidity and drying time on drying rates of seaweeds were determined. The kinetics data provided relevant information on the falling rate or constant rate of drying. In addition, physical property changes, such as the glass transition temperature, were monitored as a function of drying. The fate of temperature sensitive compounds during the drying processes were assessed.

Summary of Data Being Collected

Data Type Quantity Location
Moisture content Mass % vs time Many samples run at 3 or 4 different humidity levels, three different temperature levels, also different particle shape Samples taken from the farm site or from commercially harvested samples from mid-coast locations
Proximate analysis Mass % vs temperature Kelp samples from two seasons Food Science Laboratories
Antioxidant capacity and vitamin C Mass % vs temperature Dozens of dried samples assessed for antioxidant activity and vitamin C contents Food Science Laboratories UMaine. Results expected to be applicable to harvests from all Marine bioregions
Physical and thermal properties of kelp Product properties data (intrinsic) At least triplicate Food Science Laboratories