PROJECT REPORT NO. 14 DFO - Library I MPO - Bibliotheque Canada. [Dept. of] Fisheries. 11111111111111111111111111111111111111111111111111 89839188 Industrial Development Service PROJECT REPORT DEHYDRATED FISH FLAKE PROJECT by David Edwards, Brian Prescott and W.O. McDougall Industrial Development Service Department of Fisheries of Canada, Ottawa June 1967 DEHYDRATED FISH FLAKE PROJECT by David Edwards, Brian Prescott and W.D. McDougall Opinions expressed and conclusions reached by the author of this report are not necessarily endorsed by the sponsors of this project This was a project carried out by the Industrial Development Service of the Department of Fisheries of Canada i FOREWORD ~his report summarizes the "Dehydrated Fish Flake Projecttt carried out at the Fish Processing Experimental Plant, formerly operated by the Department of Fisheries of Canada at Valleyfield, Newfoundland. It is based on progress reports and a cost analysis prepared by L.E. Deveau and B.F. King of the Industrial Development Service of the Department of Fisheries of Canada'. SUM1VJARY The manufacture of fish-potato flakes consists of preparing, cooking and coraminuting of fish and preparing, cooking and ricing of potatoes, after which the two ingredients are blended together with additives, drum-dried and packaged. Manufacture of fish-cereal flakes is similar except that water and cereals are substituted for the cooked potatoes in the blending step. A cost study carried out on the fish-potato flake pilot plant project showed a cost of ~ 1.03 per pound for the dried product, not including depreciation, taxes or profit. Various types of fish were tried. Cod, both salted and un­ salted, was the species mostly used, although pollock and hake were also felt to have promise as a product for human consumption. Experiments in the fish-cereal process showed that of the varieties tested, which included cod, herring, flounder, whale-meat, capelin and tuna, only tuna could not be processed successfully. High solid, low sugar content potatoes are preferred, . as they give a better yield and .."hiter fish-potato flake. Various types of cereal can be ij used in the fish-cereal process. The main additives used in both types of product are monoglyceride, to tie up the free starch fraction, and an antioxidant to retard rancidity of the product in storage. Other additives bleach and season the product. Recipes have been developed by the Department of Fisheries and tests have been undertaken by FAO. The product holds promise both for human consumption and pet food. iii Foreword i Summary ii \ PART I - DEHYDhATED FISH POTATO FLAK~ PROJEpT Introduction 1 Processing Method Z a) Fish Preparation b) Potato Preparation c) Blending d) Drum Drying e) Packaging Raw Materiell 5 a) Fish b) Potato c) Additives d) Water Cost and Time Study Recipe Development 10 PART II - DEHYDRATED FISH-CEhEAL FLAKE PROJECT Introduction 13 Processing Method 13 a) Fish Preparation b) Cereal Preparation c) Blending d) Drum Drying e ) Pa ckaging f) Consumer Testing Raw IViaterial 14 a) Fish b) Cereal c} Additives d) \'later Conclusions 16 Appendix I Daily Report Sheet 17 Appendix II Flow Sheet: Dehydrated Fish-Potato Flake Project 1$ Appendix III Preliminary Results of Chilean Food Tests with Fish-Potato Flakes 19 PART 1 - DEHYDRATED FISH-PO'fATO FLAKE PROJECT INTRODUCTION This section of the report describes the various aspects of producing a dehydrated fish-potato flake product which reconstitutes with milk or water to form a nutritious food. The dehydrated food project began as a joint federal Department of Agriculture-Department of Fisheries study in 1961. Original studies on a laboratory scale, using a double drum drier with drums of size 7~ inch long x 6 inch diameter were made at Department of Agriculture facilities in Ottawa. It was first attempted to make a dehydrated product consisting of a cooked, comminuted fish only. These attempts were unsuccessful as the product could not be re- hydrated since the water binding capacity of the proteins was lost by heat denaturation. It was found that an acceptable fish product with good rehydration properties could be obtained by incorporating cooked mashed potatoes with the cooked comminuted fish. 1 It was then decided to set up a pilot plant operation on a larger scale. The site chosen was the Department of Fisheries Experimental Fish Processing Plant, Valleyfield, Newfoundland. Development. of the fish-potato flake process was carried out from 1963 to ~965. During this period sa.mples of fresh cod and salt cod-potato flakes were sent to various producers and wholesalers in the food industry in Canada and the United States. Since then samples have been sent. to such countries as India, Chile and Denmark. A pre­ liminary report of the Chilean testing, for which 500 lb of both 1 Asselbergs, E.A.M. and Chan, M.S., "Preparation and Production of Drum Dried Insta.nt Foods", }i'')(ld in Canada, (February 1962), page 21. - 2 - fresh and salt cod flakes \,\rere shipped from ValleyfiE'!ld, is included in Appendix III. Licensing arra.ngements may be made through thE'! holders of the patent on the process, Canadian Patents and Development Limited, Sussex Drive, Ottawa, Ontario. A daily report sheet, with a typical run sh01'm (Appendix I), and a fold-out display of the process (Appendix II) illustrate the method developed. PROCESSING METHOD a) Fish Preparation Fish for human consumption is filleted and skinned, giving a yield of approximately one-third of the head-on gut-out cod fish. Pin bones are not removed since they are disintegrated in the comminuter. Depending on the species and maturity of fish and the season, solid content of the raw fillets usually runs from 18~ to 20%. Cod for use· in salt cod-potato flakes is hcc?vy sa.lted skinl'9ss and is put through an extra processing step. It is desalted by soaking in cold fresh water until the salt content is reduced to approxtIl1ately 10~b (dry basis). This takes about .30 hours. Fish in tr.e thawed sta.te, v!hether salt or fresh, is boiled in water for 15 minutes. The weight lo:::;s in cooking is approximately 30~b to 40~~, most of which is ''later. There is, hovlever, a loss of soluble protein. The percentage of solids is between 21% and 2510 after cooking. The fish is then comminuted through 1/8 inch mesh. - 3 - b) Potato Preparation Potatoes are peeled, cut into French fry strips and boiled for 6 to 7 minutes. The potatoes are cooled rapidly with 45 0 F air for 6 minutes to a temperature of approximately 720 F to avoid the excessive formation of free sta.rch, which would cause stickiness in the reconstituted product. The potatoes are then riced through a 1/8 inch screen. ~ c) Blending Thd mixture of riced potato, comminuted fish and additives is then blended for 5 minutes at a slow mixing speed. Ratios of fish: potato have been tried as high as 3:1 and as low as 1/3:1. Although all combinations processed satisfactorily, a ratio of 1:1 was felt to be best since the 3:1 ratio was felt to be too expensive and the 1/3:1 ratio lacked a fish flavour. d) Drum Drying Operation Mash with an initial moisture content of 72% to 80% is dried to a moisture content of approximately 6%0 The drum dryer is a single drum type with applicator rolls. The drum is 24 inches in diameter x 48 inches long, steam heated cast iron with variable speed from 0 rpm to 5 rpm. Five 3 inch dia­ meter stainless steel unheated applicator rolls are spaced around the periphery of the drum. Only four were used, however, since the bottom one would not retain the mash very well. Although the space between the applicator rolls and the drum could be varied, it was set at approximately 7/16 inches for all rolls and retained at this throughout the project. A variable speed spreader bar is situated on the top of the drum. - 4 - Steam pressures on the drum were varied 40 psi to 90 psi. A steam pressure of about 70 psi giving a temperature on the drum sur­ face of 3100F ~ 100F was found to be the most suitable. The mash burned easily with the 90 psi setting, while the productivity was lowered at 40 psi since the speed had to be decreased to ensure proper drying. The speed setting at a particular pressure depends on the moisture content of the incoming ~sh, but at 70 psi is approximately 3.25 rpm to produce a flake with 6~ moisture a In operation the mash is dumped behind the spreader bar either by hand-held scoop or down a chute fed by a screw conveyor from a hopper. The former method was used most of the time since it was more suited to the batch-type pilot plant operation. The mix is transferred, by means of manually operated scraper bars, until each of the four rolls is covered with approximately 3/4 inch of mash. The dried sheet is peeled off the drum with a knife and broken with an auger to approximately 1/2 inch square flakes. If the flakes contain excessive moisture they are dried, before packaging, on a vibrating conveyor with variable intensity infra- red heating. e) Packaging The flakes were packaged either in 6 oz. size laminated bags (inner lining, polyethylene, aluminum foil core and paper outside) for home consumption or in nitrogen flushed 5 gallon cans for institutional use. Limited testing by the Derartment o.f Agriculture on the product packaged in the 6 oz. bags showed that after 4 to 5 months • storage with temperatures between 900F and lOOoF the product changed from - 5 - white to yellow although there was no flavour deterioration.