Derek Warren

Date of Graduation

2017

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Human Nutrion and Foods

Committee Chair

Kristen E Matak

Committee Co-Chair

Jacek Jaczynski

Committee Member

Cangliang Shen

Abstract

Better management of current resources is one method to feed an ever growing population. Currently, sarcoplasmic proteins, water soluble proteins making up 25--30% of total protein in fish, are disposed of through municipal water treatment in surimi waste wash water. There is potential for the development of a simple method to reclaim and repurpose soluble protein from surimi wash water. The objective of this research was to 1) determine if processing temperature impacted protein recovery, 2) characterize the soluble protein powder, and 3) compare shelf stability to that of a similar protein powder (80% whey protein concentrate WPC). Separation temperature variations of 4, 20, and 40°C produced minimal changes in proximate composition, amino acid profiles, mineral profiles, and fatty acid profiles. The recovered powder was rich in protein at 82.42% (dry) and met all adult essential amino acid requirements. Approximately, 3.25% lipid remained in the powder which was composed of 25% polyunsaturated fatty acids and 29% monounsaturated fatty acids. SDS-PAGE indicated large numbers of small molecular weight protein bands consistent with sarcoplasmic proteins. Recovered protein powder was less soluble than WPC. However, WPC contained lecithin and SDS-PAGE revealed proteins of low to medium molecular weights. Shelf-life stability of the protein powder was analyzed by measuring changes in color, lipid oxidation, pH, water activity, and amino acid profile with WPC and protein powder samples stored at 20 and 30°C for 9 months. The soluble protein powder stored at 30°C had the most significant reductions (p<0.05) in pH (-0.34), whiteness (-15.31) and lysine content (-10.50 mg/g protein). Results from this study suggest that protein separation temperature has limited effect on nutrient characterization and the resulting protein powder is nutrient dense. Although the powder was not as soluble and shelf-stable as WPC, inclusion of additional phospholipids (like lecithin) and antioxidants would likely improve this outcome.

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