title: Evaluation of a modified pH-shift process to reduce 2-methylisoborneol and geosmin in spiked catfish and produce a consumer acceptable fried catfish nugget-like product.
abstract: Muddy and/or musty off-flavors in farmed-raised catfish occur as a result of the absorption of geosmin (GEO) and 2-methylisoborneol (MIB), compounds produced by algae. Previous research suggests the acid pH-shift method may be able to reduce off-flavors to produce a consumer acceptable product. The objective of this research was to evaluate application of the acid pH-shift method using a shaker sieve for protein recovery and to evaluate consumer acceptability of a resultant batter-coated fried nugget-like catfish product. Farm-raised catfish were either allowed to depurate (control) or treated with 1 ppb GEO or MIB. Fillets from each replicate were collected and ground and treated by the acid pH-shift process. Samples from all treatments and replicates were evaluated for residual GEO and MIB. In addition, batter-coated fried catfish samples were prepared for a consumer sensory evaluation. Results demonstrated that the pH-shift process decreased moisture, ash, and collagen content of catfish fillet tissue (P < 0.05). Flavor of control samples was preferred (P < 0.05). Texture of catfish samples treated by the pH-shift process was preferred (P < 0.05). Results demonstrate the pH-shift process can be utilized to reduce off-flavors and increase the acceptability of a processed catfish product.
  
  
  CONCLUSIONS
  Use of a sieve as an economic alternative for the pH-shift process was evaluated for removing off-flavors from catfish. Difficulties were encountered with regard to protein recovery using the sieve and suggestions are made to, perhaps, make the process more applicable for a sieve-based recovery step. The process as described reduced off-flavors, but only 2-fold suggesting the process would work best on catfish near or just over off-flavor thresholds. Results also indicated the pH-shift process could be used to improve texture of a fried catfish product designed to be similar to chicken nuggets.
authors.affiliation: Advanced Pierre Foods, 301 W Broadway Ave., Enid, OK 73701, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Brown
authors.forename: C A
authors.initials: CA
authors.lastname: Cerruto-Noya
authors.forename: K K
authors.initials: KK
authors.lastname: Schrader
authors.forename: C W
authors.initials: CW
authors.lastname: Kleinholz
authors.forename: C A Mireles
authors.initials: CA
authors.lastname: DeWitt
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D001892:Camphanes / Q000378:metabolism*; D002397:Catfishes; D003258:Consumer Behavior; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D009284:Naphthols / Q000378:metabolism*; D017747:Seafood / Q000032:analysis*; D011795:Surveys and Questionnaires; D013649:Taste; D055815:Young Adult
chemical_list: D001892:Camphanes; D009284:Naphthols; C005536:2-methylisoborneol; C001278:geosmin