Degree

Doctor of Philosophy (PhD)

Department

School of Nutrition and Food Sciences

Document Type

Dissertation

Abstract

Oyster processing generates large quantities of oyster wash water (OWW) containing solids and undersized oyster meat (UOM), both of which contain protein and flavor compounds. The objective of this study was to produce oyster flavor powder (OFP) from byproducts of the Gulf of Mexico oyster industry and to evaluate selected quality parameters. The first chapter of this work discussed the chemical composition and volatile flavor compound profile of OFP produced from enzymatically hydrolyzed and spray-dried oyster processing byproducts. UOM was homogenized with OWW and hydrolyzed using Protease BL. Nitrogen recovery for the hydrolysate was 89.21±1.92%. Benzaldehyde, benzeneacetaldehyde, and 2-aminoacetophenone were produced during hydrolysis. Hydrolysate was mixed with maltodextrin and spray-dried. The resulting water-soluble OFP had substantial protein (23.81±0.51%) and zinc (523.81±5.90 ppm) contents. The second chapter was focused on the effect of packaging type and storage temperature on properties of spray-dried OFP (produced from UOM and OWW hydrolysates) during 12 months of storage. Storage in air-tight glass jars at 23 °C minimized changes in moisture content and water activity more so than other packaging (metallized food bags)/storage temperature (4 °C) combinations. However, packaging type and storage temperature generally did not affect powder morphology, water solubility, density, flowability, color, or volatile contents. The third chapter evaluated the quality of OFPs produced from components of OWW using enzymatic hydrolysis, ultrafiltration, and spray drying technologies. OWW was centrifuged and the obtained supernatant and sludge were ultrafiltered and enzymatically hydrolyzed, respectively. Volatile flavor components in OWW supernatant could be concentrated by ultrafiltration, and benzaldehye and 2-aminoacetophenone were generated during hydrolysis. Ultrafiltration concentrated protein from 0.46±0.00% in OWW supernatant to 5.45±0.00%, while the hydrolysate had 96.86±2.59% nitrogen recovery and 6.38±0.00% protein. The resulting concentrate and hydrolysate were spray-dried separately and together (1:1 ratio w/w) after mixing with maltodextrin. All OFPs had comparable protein contents (30.63-31.67%) and favorable essential amino acid profiles; however the water solubility, density, and production rate was lowest (P < 0.05) for OFP produced from concentrate. This research demonstrated that OFPs containing high quality protein and a unique flavor composition could be produced from byproducts of the Gulf of Mexico oyster industry.

Date

11-5-2019

Committee Chair

Sathivel, Subramaniam

Available for download on Wednesday, October 28, 2026

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