Date of Award

Summer 8-31-2020

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Food and Nutrition Sciences

Advisor

Denise I. Skonberg

Second Committee Member

Angela D. Myracle

Third Committee Member

Jennifer Perry

Additional Committee Members

Rebecca J. Van Beneden

Ian Bricknell

Abstract

European green crabs (Carcinus maenas L.) are an invasive species unintentionally introduced from Europe to the U.S. Their predation and burrowing activities have had detrimental effects on our marine habitats, aquaculture, and commercially important fisheries. Despite the large population of green crabs, they are not commercially utilized in North America as food products. The specific objectives of my research were to: 1) determine functional properties of protein recovered from green crab by isoelectric solubilization and precipitation (ISP) for potential food application, 2) investigate the application of enzymatic hydrolysis for deriving bioactive compounds from green crab proteins and examine the bioactivity changes of green crab protein derivatives after simulated human digestion, and 3) evaluate whether enzymatic hydrolysis by commercial proteases improves functional properties of green crab proteins in food formulations.

In the first study, the results showed that ISP processing can recover functional proteins from green crabs, and that the recovered proteins could potentially be successfully applied as ingredients in various food emulsions (e.g. sauces or chowders) and food gels (e.g. surimi or other meat analog products) to improve food product quality.

In the second study, enzymatic hydrolysis using commercially available proteases and health-promoting effects of the hydrolysates were evaluated. Protein derivatives produced by Protamex had the potential to alleviate type 2 diabetes by inhibiting carbohydrate digesting enzymes and secreting an insulin stimulating molecule. Also, no additional processing would be required to stabilize their antidiabetic effects as food ingredients since they were stable to simulated human digestion.

The last study investigated the functional properties of protein derivatives obtained through enzymatic hydrolysis. Mild hydrolysis by Protamex and combination of Protamex and Flavourzyme for 15 min improved the foaming activity of the crab mince and combination of Protamex and Flavourzyme generated antioxidant hydrolysates that may contribute to extended shelf-life of food products.

These studies provide valuable information for the development of value-added food ingredients from green crab using ISP processing and enzymatic hydrolysis, and for the introduction of green crab proteins to the food industry, potentially contributing to food product development and the creation of new markets for this invasive species.

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