Date of Award

Summer 8-21-2020

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

Jason Bolton

Third Committee Member

Bob Bayer

Additional Committee Members

Marry Ellen Camire

Jennifer Perry

Balunkeswar Nayak

Abstract

Sous-vide and high pressure processing (HPP) are promising techniques in the development of high-quality seafood products. Lobsters are high-value seafood products that are highly susceptible to being overcooked using conventional methods, producing a tough and rubbery texture. Lobsters are usually sold either live or frozen due to their high perishability. The application of sous-vide cooking may provide evenly cooked lobster products with a succulent and juicy texture, while HPP may increase the shelf-life of lobster products without the use of additives. The objectives of this research were to: 1) evaluate the impact of three different sous-vide cooking conditions on physicochemical properties and consumer acceptability of lobster tails, 2) evaluate the effects of HPP application on physicochemical properties of vacuum-packaged raw and subsequently sous-vide cooked lobster tails, and on consumer acceptability of the sous-vide cooked lobster tails, 3) determine the effects of HPP on the refrigerated shelf-life of vacuum-packaged raw and subsequently sous-vide cooked lobster tails. In the first study, hand-shucked lobster tails were vacuum-packaged in boilable bags and sous-vide cooked to internal temperatures of 55, 60, and 65 °C for equivalent times values (208, 45, and 10 minutes, respectively) aimed to control the target foodborne pathogen, Listeria monocytogenes. Results revealed that sous-vide cooked lobster tails at all parameters were more tender than those conventionally cooked in boiling water. In addition, no significant differences were observed in lobster qualities among the sous-vide cooking parameters. In support of the physicochemical results for sous-vide cooked tails, hedonic testing confirmed that there were no significant differences in consumer acceptability response to the sous-vide cooking parameters. Therefore, the 65 °C for 10 minutes treatment was chosen for subsequent studies because it represents the most convenient cooking treatment. In the second study, hand-shucked raw lobster tails were high pressure processed at two moderate processing pressures (150 or 350 MPa) and two processing times (5 or 10 min), then half were subsequently sous-vide cooked at 65 °C to achieve a core temperature of 65 °C/10 minutes. Hardness of raw tails decreased in the 150 MPa/10 min samples, while the shear force to cut raw and sous-vide cooked samples increased in response to 350 MPa for 5 or 10 minutes. Although HPP induced significant textural changes, consumer acceptability of the HPP pretreated sous-vide cooked lobster tails was not influenced. The third study investigated the effects of 150 MPa or 350 MPa for 10 minutes on microbial, sensory, and physicochemical qualities of raw and subsequently sous-vide cooked (65 °C) lobster tails during 28 days of storage at 2 °C. Higher pressure (350 MPa) samples maintained acceptable quality throughout 28 days storage compared to the control and 150 MPa treatment, although a considerable histamine content was observed in raw lobsters which reached the hazard limit after 14 days in the 350 MPa treatment. Furthermore, HPP pretreatment did not contribute to additional shelf-life extension of the sous-vide cooked lobster tails. The results of these studies have important implications for the lobster industry and for consumers of value-added lobster products. These results suggest that HPP has the potential to increase the commercial availability of refrigerated raw lobster tails and to be applied in combination with sous-vide cooking to produce high-quality and consumer-acceptable ready- to-eat lobster products.

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