Md. Masud Rana
Department of Fisheries Technology, Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh
Subhash Chandra Chakraborty
Department of Fisheries Technology, Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh
Batashi, Salt-smoke-dried, Shelf-life, Chaluni
Machua bazar, Mymensingh, Bangladesh
Postharvest and Agro-processing
Sample Collection: For the preparation of salt-smoke-dried products from freshwater fish species, batashi; (Neotropius atherinoides) was collected as fresh from the Machua bazar, Mymensingh town by direct contact with supplier early in the morning. The collected fresh fish samples were carried in ice stored condition to the laboratory of Fisheries Technology, Bangladesh Agricultural University. Washing and Dressing of Fish: At first the fishes were washed in potable water, weighed the whole fish on a sensitive balance then dressed (gutting, finning and spinning) and weighed the dressed fish in the laboratory. Brining, dewatering, air drying and pre-smoking treatment:After draining out water the fishes were allowed for salt treatment. The fishes were immersed into a plastic bucket containing 25% salt solution for 5 min. after that kept the fishes on a plastic tray for drying at room temperature for about 10 minutes. After air drying the fishes were placed inside the smoking kiln with the help of removable wire mesh tray. Smoking: The lower chamber of the smoking kiln had the facilities of burning saw dust or wood chips on an iron bowl so to produce a continuous and a homogenous hot smoke. The temperature inside the smoke chamber was recorded at every 10 minutes and the temperature was controlled by the exit cover of the kiln. During the smoking procedure, the smoke temperature inside the smoking kiln was recorded by a sensitive thermometer. The desired temperature ranged between 50-550C and was maintained manually by controlling the outlet of the smoking chamber. During the smoking operation fishes were turned upside down in the middle period, by using a corrosion free metal element to make the sample smooth and steady in texture and appearance. After smoking, products were cooled for 15-20 minutes at room temperature. Cooling firmed the muscle and facilitated to prevent breaking of smoked fish. Drying Procedure: The smoked fish was than dried with the help of a Ring tunnel dryer. The structure of Ring tunnel is very simple compared to other dryer (Solar tunnel dryer, Rotary dryer). A 6.5 to 7 feet long piece of bamboo was splitted equally in to 6-7 parts the rear end unsplitted. Several rings (outer rings) 1-15 ft diameters were made of split bamboo were tied up with individual splitted bamboo. Round thin-meshed sieves (chaluni) made of bamboo inside the shreds were set and tied at regular distance to give a shape of a robust torpedo. The vertical distance between two sieves was about 1.7 feet. Four sieves with similar manner were fixed inside the circular frame. Small fishes were spreaded on these sieves inside the ring tunnel carefully for sun drying. The tunnel was installed vertically keeping the unspiltted bamboo at the upside. After loading of the trays with smoked fish all sides of the tunnel was carefully covered by the polythene except a little whole was kept open at the upper portion of the ring tunnel for the exit of warm air. Analysis: For quality and shelf life analysis sampling was done on every 15 days interval for the sample kept at ambient and refrigeration temperature. The nutritional quality on proximate composition (moisture, crude protein, lipid and ash) of the fresh and salt-smoked, salt-smoked dried and control dried fish was carried out in triplicate according to AOAC 1990. Total bacterial count of fresh, salt-smoked, salt-smoke-dried and control dried fish samples were done on nutrient agar media by Standard Plate Count (SPC) method. This method consists of growing the bacteria in a nutrient culture petridish and counting the colonies in the petridish which developed at defined incubation period (35-37°C for 48 hours).
Res. Agric. Livest., Fish. Vol. 3, No. 3, December 2016: 443-451
Journal