Process Development of Smoked Hybrid Clarias Catfish Fillets Using Fresh Lemon Grass Extract

Abstract

Crude lemon grass extract was prepared by blending fresh lemon grass in water (1:1 w/v), filtering and adding 5% NaCl (w/v). Soaking fresh catfish fillets in crude lemon grass extract for 45 minutes prior to drying at 50°C in a hot-air oven for 1 h before smoking for 1 h at 60°C and drying for
45 min at 60°C resulted in products with the highest consumer acceptability. The water activity (a_w) of the products was 0.932, color parameters L*, a* and b* were 44.41, 6.36 and 9.40, respectively while moisture, protein, fat, ash and carbohydrate contents were 62.1, 24.0, 10.3, 1.2 and 2.4%, respectively. Total count for bacteria was 3.25x10² and for yeast and mold was <3 CFU/g. The acceptability of the products based on appearance, color, odor and flavor ranged from moderate to high. The shelf life of smoked, catfish fillets treated with lemon grass extract could be extended from two to nine days when packed in PA/LDPE bags under atmospheric conditions and stored at ambient temperature and extended from 9 to 36 days if stored at a chilled temperature (4±2°C). The shelf life of treated samples packed under a vacuum could be extended from 5 to 17 days at ambient temperature and from 15 to more than 60 days at 4-6°C.