Date of Award

Spring 5-6-2022

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Food Science and Human Nutrition

Advisor

Denise I. Skonberg

Second Committee Member

Jennifer J. Perry

Third Committee Member

Mary E. Camire

Additional Committee Members

Jason Bolton

Charles Yarish

Abstract

The annual growth rate of harvested edible seaweed in the United States’ developing seaweed aquaculture sector leaped from 8% in 2014 to a predicted 18 – 25% from 2019 – 2025 due to increased demand. For continuous growth of the edible seaweed market, addressing challenges in food safety, perishability, processing, and product development are vital. The specific objectives of this research were to: 1) evaluate the effect of pre-freezing blanching procedures on the qualities of frozen sugar kelp, 2) evaluate the impact of blanching, freezing and fermentation on kelp quality, 3) determine the effect of rehydration temperatures on kelp quality, and 4) evaluate the survival of four pathogens inoculated on kelp stored at different temperatures. For objective one, whole blade and shredded sugar kelp were subjected to different blanching methods, temperatures, and times, prior to one-year frozen storage. Blanching resulted in relatively higher quality frozen product than unblanched frozen kelp. Vacuum-packed blanching at higher temperature for longer time resulted in good kelp quality for at least six months of frozen storage. In objective two, blanching and freezing positively impacted kelp quality and consumer acceptability of kelp salad. Fermenting kelp to produce sauerkraut showed promise for new product development, and freezing prior to fermentation did not impact the overall liking scores of kelp sauerkraut. Results confirm that frozen storage is an acceptable practice prior to further value addition of kelp. Dried kelp was rehydrated at three different water temperatures. Rehydration time decreased as initial water temperature was increased. Most kelp qualities were not notably different among rehydration treatments. However, rehydrated kelp was greener and less chewy than raw kelp, which may positively affect its consumer acceptability. In the last study, all four pathogens survived storage regardless of the temperature. Survival for all species was greatest at 22 > 10 > 4 °C storage. Results confirm the need for strict adherence to temperature control, and adoption of supplemental measures to enhance product safety. These studies provide valuable information for extending the shelf-life of sugar kelp and producing high quality products, which are vital to the growing seaweed industry and for consumers of seaweed products.

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