The influence of fermentation and salting on the bacterial, chemical and sensory characteristics of catfish (Clarias buthupogon) based marinate in Nigeria

Abstract

Catfish (Clarias buthupogon) was treated with 10% w/w NaCl and 15% w/w NaCl with or without the addition of spices (1% w/w garlic powder and 1% w/w red pepper) and allowed to ferment naturally and at room temperature (28 ± 2°C) for two weeks. Bacte rial, chemical and sensory analyses were carried out on the unfermented non-salted and fermented salted samples of the fish species. Results obtained revealed that fermentation and salting caused a remarkable reduction in the total bacterial count from 2.29×10 6 to 3.80×10 5 cfu/g. There was also reduction in pH from 7.29 to 5.26. The predominant bacteria isolated from the samples were Lactobacillus sp, Staphylococcus spp for the unfermented non salted and fermented salted samples respectively while total titratable acidity increased from 0.63 to 1.44%. Chemical analysis result showed that fat and ash contents increased with fermentation and salting while moisture, protein and Nitrogen free Extracts (NFE) contents decreased with fermentation and salting of C. buthupogon. Free fatty acid, peroxide value and total volatile base (TVB) also showed increase with fermentation. Peroxide value ranged from 5.22 mEq/kg for unfermented non-salted to 8.43 mEq/kg for fermented 15%w/w salted products while total volatile base increased from 5.63 mgN/100 g unfermented non-salted to 16.85 mgN/100 g for fermented 10%w/w salted products. Sensory analysis indicates that stew containing fermented samples treated with 10%w/w NaCl and spices were more preferred than others.

Improvement of Taste Enhancer Condiment Processing and Safety Using Marinade and bio-preservation of Cassava Fish (Pseudotolithus Sp)

“…The high values of TVN measured in inoculated products were due to the activity of endogenous fish flora and to the proteolytic activities of the inoculated strains of S. xylosus as reported by Tremonte et al, 2010). The same trend of TVN content was reported during the fermentation of Clarias buthupogon for the production of fermented fish (Ezeama, 2012). This proteolytic activity was desirable for flavor development during the fermentation (Kaban & Kaya, 2009;Tremonte et al, 2010).…”

“…So, Enterobacteriaceae counts were significantly (p ˂ 0.05) reduced by the marinating process. Sallam (2008) and Ezeama (2012) reported that the use of citric acid, salt and spices have bacteriostatic and bactericide effects on the flora.…”

“…However, preservation of fish in the tropical countries is difficult due to its extreme perishability, the lack of adequate infrastructures of preservation, the climatic conditions and the poor handling which favor its spoilage in few hours (Kindossi et al, 2012). Fish post-capture loss can be limited by developing processing methods such as drying, smoking and fermentation sometimes in combination with salting (Anihouvi, Kindossi, & Hounhouigan, 2012;Ezeama, 2012;Kindossi et al, 2012). Natural fermentation is one of the processing methods mostly used over the world in combination with salting followed sometimes by drying (Wang, Xia, Gao, Xu, & Jiang, 2017).…”