Design and Evaluation of a Vacuum Fryer for “Greenshell” Mussels Meat

ABSTRACT

The Appropriate Technology Center, Department of Agricultural Engineering, College of Agriculture, Central Philippine University, Iloilo City in collaboration with the Assosasyon sang Magagagmay nga Mangingisda sang Roxas City (AMMARO) and the Department of Science and Technology, Provincial Science and Technology Center (DOST-PSTC) in Roxas City had designed and evaluated a vacuum fryer for frying “greenshell” mussels’ meat. The project was carried out from May 15, 2002 to November 29, 2002. The vacuum fryer, basically consist of the different components as follows: (1) frying chamber, (2) heating chamber, (3) burner, (4) pneumatically-operated product dipper and lifter, (5) vacuum tanks, (6) water storage tank, and (7) pressure pump. The frying chamber where the “greenshell” mussels’ meat is fried has a diameter of 0.60 m and a height of 1.2 meter. It is made of 1/8-in thick stainless steel plate to prevent salt corrosion. The lower portion of this chamber is developed by another cylinder with a diameter of 0.8-m and a height of 0.7 m which serves as the heating chamber for the fryer. This chamber is also made of 1/8-in thick stainless steel plate thoroughly welded into its base and to the frying chamber to prevent oil leakage. Inlet and outlet pipes are provided for both chambers for loading and unloading of oil. An exhaust pipe is also provided for the heating chamber to automatically release any possible pressure build up in the chamber during operation. An industrial-size LPG burner is utilized to heat the oil. It is placed directly beneath the heating chamber to supply the heat needed for frying. The pneumatically-operated product dipper and lifter was locally fabricated out of stainless-steel material and hard-rubber gasket. Two vacuum tanks are used to generate the required vacuum pressure for the frying chamber. These tanks are made of 1/8-in thick mild steel plate having a diameter of 0.6 m and a height of 1.22 m. These tanks create vacuum while the water is transferred from one tank to the other, Pumping of water is done by a ¾-hp PEDROLLO pump. An 82-gal capacity water tank is used to temporarily store the water that is pumped from the two vacuum tanks. Performance evaluation showed that the machine uses 160 liters of frying oil and 60 liters of heating oil. A vacuum pressure of the frying oil can be elevated to the level of 130 within 2 hours of continuous firing using the LPG burner. One to two kilos of “greenshell” mussels’ meat can be satisfactorily fried within 5 to 6 minutes. The products produced are crispy and less oily. Frying recovery of the product averaged at 32%. Electrical power and fuel consumption average to 1.27 kW and 1.06 kg per load, respectively. The initial investment required for the vacuum fryer is P205,000.00. The estimated life span is 7 years and a salvage vale of 10%. Interest on investment, repair and maintenance, and insurance are estimated to be 24, 10, and 3 percent, respectively. At 15.36 kg per day product output, two persons to operate the machine, one tank fuel consumption per two-day operation, and electrical load of 1.27 kW at P6.00 per kW-hr, the cost of producing vacuum fried green shells is P129.96 per kilogram. Assuming a P150.00 cost per sack of “greenshell” mussels, a recovery of 8 kilos of “greenshell” mussels meat per sack, and a selling price of P700.00 per kilo of the vacuum- fried product, the total net income that can be derived from the operation is P508,253.18 per year. The return on investment s 247.9% assuming an 8 hours operation per day, 20 days per month, and 3 months per year. The benefit cost ratio is 4.27. The payback period is 0.403 year which mean that the cost of the machine can be recovered within 5 months operation.