Evaluation of Catfish Skin Hydrolysates as a Glazing Material for Air-Blast Frozen Shrimp

Authors: PEREZ, C.G. - Louisiana State University; BONILLA, F. - Louisiana State University; REYES, V. - Louisiana State University; Bechtel, Peter; SATHIVEL, S. - Louisiana State University

Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 3/19/2016
Publication Date: 7/17/2016
Citation: Perez, C., Bonilla, F., Reyes, V., Bechtel, P.J., Sathivel, S. 2016. Evaluation of Catfish Skin Hydrolysates as a Glazing Material for Air-Blast Frozen Shrimp. Annual Meeting of the Institute of Food Technologists. http://ift.planion.com/Web.User/AbstractDet?ACCOUNT=IFT&ABSID=15445&CONF=IFT16&ssoOverride=OFF&CKEY=.

Interpretive Summary:

Technical Abstract: Catfish is one of the most widely consumed seafood in the United States. A by-product of this consumption is a large quantity of catfish skin (CS), approximately 8,200 metric tons in 2014. Enzymatic hydrolysis is used to produce protein hydrolysates from the skin. These hydrolysates have considerable antioxidant properties. Because shrimp mainly contain polyunsaturated fatty acids, shrimp may be susceptible to lipid oxidation during frozen storage. It is expected that glazing shrimp with catfish skin hydrolysates (CSH) would reduce the rate of lipid oxidation and preserve quality characteristics during frozen storage. The objective of this study was to evaluate CSH as a glazing material for air-blast frozen shrimp. CS was obtained from a local seafood market. It was cleaned, minced, and hydrolyzed with food grade alkaline protease (0.5% w/w) at 60 °C for 30 min. CSH were obtained after centrifugation at 7000 rpm for 20 min. Fresh shrimp were manually de-headed, de-shelled and placed in an air-blast freezer (-20 °C) for 30 min before glazing. Shrimp were immersed in CSH solution for 1 min, drained for 30 s, and placed back in the air-blast freezer for completion of freezing. The shrimp were placed into Ziploc freezer bags for storage at -20 °C. Distilled-water-glazed shrimp (DW) and non-glazed shrimp (NG) were used as controls. CSH were evaluated for degree of hydrolysis and free radical scavenging activity (SA). Shrimp samples were analyzed during 60 days of frozen storage for oxidation (thiobarbituric-acid-reactive-substances; TBARs), color, texture, aerobic plate counts (APC), and moisture content. Triplicate experiments were conducted and the data was statistically analyzed (a = 0.05). CSH had 36.15±1.11% degree of hydrolysis and 35.5±3.50 mM Trolox equivalent/L SA. After 60 days frozen storage, Shrimp glazed with CSH (1.14±0.07) had slightly lower lipid oxidation than DW (1.27±0.17) and NG (1.36±0.09). However, no differences were found between treatments at 60 days of frozen storage APC, texture, moisture, and color. This study demonstrated CSH could be used a glazing agent to minimize lipid oxidation in shrimp during frozen storage for 60 days.