4 °C - the National Sea Grant Library
4 °C - the National Sea Grant Library 4 °C - the National Sea Grant Library
FUTURE WORK The ohmic system performed to its design specifications. These results should encourage further work for improvement of the ohmic thawing unit towards scale-up and commercial operation. These are: 1. The thermistor-based surface temperature monitoring method should be replaced by a fiber opticsbased method. When a liquid crystal that changes its color at the desired set point temperature is coated to the tip of a plastic fiber, it can detect temperatures much safer, since there is complete isolation of the circuit boards from the high voltage and current of the electrodes. This method is also much less expensive than using thermistors. 2. The current system operates in batch mode. Industrial applications require continuous operation. A system of rollers can be designed that would act both as the electrodes, and as the transport mechanism for the blocks on a conveyor system. 3. The inherent disadvantage of the current system is that it supplies the same voltage to all 8 quadrants, bound by the “limiting quadrant”. The high conductivity of the limiting quadrant causes that all other quadrants have lower amps passing through them. Since heat generated is proportional to the square of the current, they thaw slower. A system that can supply diferent levels of voltage to diferent quadrants would solve this problem. Ideally, each quadrant would have its own voltage, set current and control system. 4. A positive method of monitoring the electricity used, and therefore predicting the end-point of thawing would be to attach a watt-meter to the unit. This is quite inexpensive, and should be the first modification to the current system. 5. Optimization of the set current profile during thawing depending on shrimp species, size, shell on/off, shrimp to water ratio in the block, etc. This will also build the database of knowledge necessary to apply ohmic thawing effectively to commercial operations. 6. There are reports in the literature that coating of the electrodes may minimize or prevent electrolysis at the electrode in the high voltage and high current density operations. This would extend the life of the electrode, and minimize the deleterious effects of the interaction of gases evoking at the electrode (oxygen, chlorine, etc.) with the food. REFERENCES Bough, W. A and Perkins, B. E. 1977. “Recovery of by-products from seafood effluents.” Proceedings of the Interstate Seafood Seminar, Ed. W. R. Hess, Jr. pp:201-273. VPI Seafood Extension Unit, Hampton, VA Current Fishery Statistics, 1994. No: 9300. Fisheries of the U.S. USDC. Washington, D.C.
Henderson, J.T. 1993. Ohmic Thawing of Frozen Shrimp: Preliminary Technical and Economic Feasibility. Master of Science Thesis, University of Florida. enderson, J. T., Balaban, M. 0. and Teixeira, AA. 1993. Ohmic Thawing of Frozen Shrimp : Preliminary Tech. & Economic Feasibiity. Proc. Workshop on Process Optimization and Minimal Processing of Foods. Escola Superior de Biotechnologica, Porto, Portugal. Sept. 23, 1993. James, S.J., and Bailey, C. 1984. The Theory and Practice of Food Thawing. In: Thermal Processing and Quality of Foods, edited by P. Zeuthen et. aI. Elsevier Applied Science. London. Karel, M. and Fennema, O. 1975. Principles of Food Science. Part II. Physical Principles of Food Preservation. Marcel Dekker, Inc. New York NY. Luzuriaga, D.A, Roberts, J. S. and Balaban, M. O. 1994. Electrical Conductivity of Frozen Shrimp and Flounder at Different Temperatures and Voltage Levels. J. Aq. Food Prod. Technology (Submitted). Meilgaard, M., CivilIe, G. V., and Carr, B. T. 1991. Sensory Evaluation Techniques. 2nd. edition. CRC Press, Inc. Boca Raton, FL. pp. 60 - 66, 338, 342. Miyajima, L. 1993 Singleton Seafood Co. Personal Communication. Peplow, A. 1975. “Effects of Ice Storage and Thermal Processing on the Proximate, Mineral, Extractable Protein, and Thiamine composition of Shrimp.” A thesis presented to the graduate school of the &.iversity of Florida, Gainesville, FL. Sastry, SK. 1992. Ohmic heating of foods. FPEI News 26(l) : l,l0-11. Singh, J.P. and Heldman, D. R. 1993. Introduction to Food Engineering. 2nd edition. Academic Press. New York, NY. Speck, M. L. 1976. Comnendium of Methods for the Microbiological Examination of Foods. American Public Health Association, Washington D.C. p. 79.
- Page 38 and 39: (4) advisory committee, and all con
- Page 40 and 41: IRRADIATION TO ENSURE HYGIENIC QUAL
- Page 42 and 43: food. Often, food manufacturers hav
- Page 44 and 45: BACTERIA D-VALUE (kGy) E. coli 0.15
- Page 46 and 47: ECONOMICS OF IRRADIATION OF FISH AN
- Page 48 and 49: B. Market Testing of Irradiated Foo
- Page 50 and 51: The Agreement on the Application of
- Page 52 and 53: Table 1. Optimum radiation dose lev
- Page 54 and 55: Loaharanu, P. 1973. Gamma irradiati
- Page 56 and 57: EFFECTS OF LOW-DOSE GAMMA IRRADIATI
- Page 58 and 59: diving bell and lowered into the wa
- Page 60 and 61: 12 1 Survival Curve for Standard Pl
- Page 62 and 63: 6 D value = 0.05 kGy ‘A. 0 / I I
- Page 64 and 65: Dvalue=O.S9kGy 3.8 a’, 3.6 . 3.4
- Page 66 and 67: 8 0 . 0.1 0.2 0.3 0.4 0.S 0.6 rlrah
- Page 68 and 69: Conclusion In this study, low dose
- Page 70 and 71: processed and packaged product. A m
- Page 72 and 73: Table l.Procedures schematic for ef
- Page 74 and 75: (hydrogen peroxide) produced from t
- Page 76 and 77: Johns, H.E. and Cunningham, J.R. 19
- Page 78 and 79: k TBF#hoursCtime between split dose
- Page 80 and 81: AUTOMATED OHMIC THAWING OF SHRIMP B
- Page 82 and 83: A computer program was developed in
- Page 84 and 85: RESULTS AND DISCUSSION The computer
- Page 86 and 87: 78 Quadrant 1 0 20 40 60 80 100 Tim
- Page 90 and 91: Using Edible Film to Improve Smoked
- Page 92 and 93: LOG CFU / Sq cm 0 3 6 9 12, 15 18 2
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- Page 98 and 99: For samples stored at l0°C, no sig
- Page 100 and 101: (3) 10 oz copolymer polyethylene ca
- Page 102 and 103: Total Volatile Base Components of P
- Page 104 and 105: Log Anaerobic Plate Counts of Packa
- Page 106 and 107: 0, 600 500 - :: 7 400 - 2 z 300 - k
- Page 108 and 109: Log Aerobic Plate Counts of Package
- Page 110 and 111: The variables that correlated well
- Page 112 and 113: Woyewoda, A.D., S.J. Shaw, P.J. Ke,
- Page 114 and 115: used to evaluate both heating and c
- Page 116 and 117: minimize the chances for product re
- Page 118 and 119: Part II Evaluation of the cooling p
- Page 120 and 121: Table 1. Laboratory analyses on con
- Page 122 and 123: REFERENCES APHA, 1984. Compendium o
- Page 124 and 125: market and economic studies focusin
- Page 126 and 127: The foreign demand for U.S. exports
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- Page 132 and 133: during the same period. The butterf
- Page 134 and 135: 48,693 mt/yr in 198690. The primary
- Page 136 and 137: U.S. Landings consistently increase
Henderson, J.T. 1993. Ohmic Thawing of Frozen Shrimp: Preliminary Technical and Economic<br />
Feasibility. Master of Science Thesis, University of Florida.<br />
enderson, J. T., Balaban, M. 0. and Teixeira, AA. 1993. Ohmic Thawing of Frozen Shrimp :<br />
Preliminary Tech. & Economic Feasibiity. Proc. Workshop on Process Optimization and Minimal<br />
Processing of Foods. Escola Superior de Biotechnologica, Porto, Portugal. Sept. 23, 1993.<br />
James, S.J., and Bailey, C. 1984. The Theory and Practice of Food Thawing. In: Thermal Processing<br />
and Quality of Foods, edited by P. Zeu<strong>the</strong>n et. aI. Elsevier Applied Science. London.<br />
Karel, M. and Fennema, O. 1975. Principles of Food Science. Part II. Physical Principles of Food<br />
Preservation. Marcel Dekker, Inc. New York NY.<br />
Luzuriaga, D.A, Roberts, J. S. and Balaban, M. O. 1994. Electrical Conductivity of Frozen Shrimp<br />
and Flounder at Different Temperatures and Voltage Levels. J. Aq. Food Prod. Technology<br />
(Submitted).<br />
Meilgaard, M., CivilIe, G. V., and Carr, B. T. 1991. Sensory Evaluation Techniques. 2nd. edition.<br />
CRC Press, Inc. Boca Raton, FL. pp. 60 - 66, 338, 342.<br />
Miyajima, L. 1993 Singleton <strong>Sea</strong>food Co. Personal Communication.<br />
Peplow, A. 1975. “Effects of Ice Storage and Thermal Processing on <strong>the</strong> Proximate, Mineral,<br />
Extractable Protein, and Thiamine composition of Shrimp.” A <strong>the</strong>sis presented to <strong>the</strong> graduate<br />
school of <strong>the</strong> &.iversity of Florida, Gainesville, FL.<br />
Sastry, SK. 1992. Ohmic heating of foods. FPEI News 26(l) : l,l0-11.<br />
Singh, J.P. and Heldman, D. R. 1993. Introduction to Food Engineering. 2nd edition. Academic<br />
Press. New York, NY.<br />
Speck, M. L. 1976. Comnendium of Methods for <strong>the</strong> Microbiological Examination of Foods.<br />
American Public Health Association, Washington D.C. p. 79.
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