Date of Award

5-2014

Level of Access Assigned by Author

Open-Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Food and Nutrition Sciences

Advisor

Denise I. Skonberg

Second Committee Member

Tom C. Yang

Third Committee Member

Mary Ellen Camire

Abstract

High pressure processing (HPP) is a non-thermal method used to increase food safety and shelf-life. HPP has been explored for meat tenderization, with conflicting results depending on rigor status during HPP. In the seafood industry, HPP is used to shuck oysters and lobsters, but has been minimally investigated for use in processing abalones. Abalones are shellfish with high perishability that are typically sold live or frozen in the U.S. HPP has been proposed as an alternative method to process shucked abalone meats. The objectives of this research were to evaluate the effects of 1) rigor status during HPP on abalone quality, 2) of HPP on subsequently cooked abalone, 3) processing pressures of <500 MPa on shelf-life, and 4) HPP followed by papain treatment on physicochemical qualities of abalone.

In study 1, abalones were processed either pre- or post-rigor at 100 or 300 MPa for 1-5 min. Processing abalones pre-rigor caused significant (p<0.05) toughening of the foot compared to the control and post-rigor treatments. Foot color lightened significantly as pressure increased, and was lighter in the post-rigor treatments. In study 2, uniform pieces of HPP abalone were boiled for 15 s. HPP did not affect cooked meat texture, but did cause significant increases in lightness of cooked treatments. For study 3, shelf-life of HPP abalone was evaluated over 35 days at 2ºC using microbiological, biochemical, and physical quality parameters. HPP abalone meat processed at 300 MPa did not exceed freshness indices for 25 days. In the final study, HPP abalones were vacuum tumbled with papain solutions (0.5% or 1.0% w/v), resulting in significantly more tender meat than in the controls. The proteolytic effect of papain was qualified by protein gel electrophoresis and scanning electron microscopy.

The results of these studies have important implications for the abalone industry. HPP could be used to improve the shelf-life of shucked abalone, as well as to lighten color without chemical bleach. Subsequently cooked HPP abalone meat did not differ in texture compared to cooked non-HPP meat, and papain treatment at the concentration and activity used in the final study effectively tenderized HPP abalone meat.

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