Identifier

etd-06062012-124944

Degree

Master of Science (MS)

Department

School of Nutrition and Food Sciences

Document Type

Thesis

Abstract

A processing method for shrimp in the Gulf of Mexico region is to place mechanically peeled shrimp in plastic bags in a retail box and add a mixture of water, sodium chloride, and sodium tripolyphosphate (STPP). The box is then placed in frozen storage. As the shrimp and solution freeze, there is a potential for the shrimp to absorb solution inconsistently. When used properly, phosphates help to retain natural moisture, and protect the product through freezing and thawing. However, excessive absorption of phosphate solution can lead to a loss of functional benefits in the finished product. When thawed, the over-treated product has a glassine appearance, soft texture, and occasional soapy taste. The product resists natural changes during cooking, such as development of pink color and coagulation of protein. Some local processors consider this the industry standard, while others have a desire to produce a higher quality product line. The objective of this study was to determine the potential of a vacuum tumbling method for application of condensed phosphate solutions to produce a value-added, wild-caught, Louisiana Gulf shrimp product. Shrimp containing no added phosphates from Louisiana, Honduras, South Carolina, and Texas were obtained, peeled, and deveined. Shrimp, plus solutions containing sodium tripolyphosphate (STPP) and sodium acid pyrophosphate (SAPP), were added to a clear tumbling chamber and tumbled under 22 mm Hg vacuum until no free solution was visible. Treated shrimp were compared for moisture content in raw and cooked products, cook-cool loss, and changes in protein content and microstructure after freeze thaw. Standardization of the uptake data showed that there was a consistent level of uptake using the SAPP blend. Standardized cook-cool data indicated that the STPP treatment had equal cook-cool loss values compared to the control. The tumbled shrimp also had reduced protein solubilization. The measurement of muscle fiber area showed that it is difficult to determine a relationship between fiber area to level of moisture or uptake in the finished product. This study has shown promising initial results for improvements in value-added shrimp using vacuum tumbling. Scale-up studies should be performed to determine its feasibility on an industrial scale.

Date

2012

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Lampila, Lucina E.

DOI

10.31390/gradschool_theses.2831

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