US2083738A - Process for preserving edible material - Google Patents

Description

Patented June 15, 1937 PATENT OFFICE PROCESS FOR PREBEBVING EDIBLE MATERIAL Johan Olsen Nygaard, Oslo, Norway No Drawing. Application October 12, 1934, Serial No. 748,137. In Norway September 24, 1931 6 Claims. (cl. 99-158) This invention relates to a process of food preservation, and more particularly to the preservation for storage over a considerable period of time of the lean meat of whale, seal, and other sea mammals. It is the principal object of the invention to provide a process which permits the utilization of fleshy material of the larger sea mammals heretofore discarded or only to a little degree utilized for lack of a suitable method of preserving and transporting the same.

For example, in the whaling industry the catch is ordinarily made in the ice regions, in wholly uninhabited places frequently requiring a voyage of weeks or months to land. Enormous quantities of material suitable for edible or medicinal purposes such as the nonfatty portions of the flesh, the glands, 'the bones, and the internal organs of the whales, are of little or no value in the rendering of oil and are thrown overboard, this practice obviously involving a tremendous loss, particularly since the use of the whale for the extraction of the oil alone necessitates a catch of a much greater number of whales for profitable operation-than wouldbe necessaryif substantially the whole of the whale could be converted into a useful product. Obviously a possible result of this practice is the extermination of the whale, it having been long appreciated that the experience of the whaling industry in northern waters, where the whales have been killed off or driven away so that whaling is no longer profitable, is likely to be repeated in the Antarctic to which the whaling industry is now largely confined.-

It is of course most convenient and profitable to effect the rendering of the blubber at sea, but in spite of intensive work and many expensive experiments no usable and sufllciently productive practical method for the whaling industry has heretofore been discovered for conserving the enormous quantities of leaner parts of the whale on board ship for transport to the markets, and the storage of considerable quantities of flesh, bones and internal organs without preservation for the period of time required to reach the market, frequently through the tropics to the northern hemisphere, is obviously impractical.

.By means of the present invention it'is possible in a practical way and economically to preserve and store such portions of the whale as have heretofore been discarded without material depreciation from decomposition, pending the delivery of the material to distant places where facilities for the completion of the treatment of the material for use as food, or for medicinal or other purposes are available. It is thus possible to transfer this material from the Antarctic, in which more than of the whaling takes place at the present, to land stations and markets for the product which are principally situated in the Northern Hemisphere, the material being sumciently sterilized and preserved to prevent decomposition on the trip through the tropical zones.

More specifically it is an object of the invention to dehydrate the comparatively fat-poor flesh, bones, and .internal organs of whales and other sea mammals by heating the same with oil, preferably derived from the mammals, the process preferably being carried out under reduced pressure in order to avoid high temperatures and consequent injury to the tissues and the coagulation of albuminous matter.

In carrying out the process, the material undergoing treatment is preferably comminuted by grinding, cutting, or pressing, for instance by the employment of a mill which passes the material through a screen having apertures of from 12 to 20 mm. in diameter. The divided material is then-introduced, together with a suflicient quantity of oil, into a closed boiler having pressure control means associated therewith, the material and the oil being preferably whipped or stirred together either before or after introduction into the boiler to form a medium of semiliquid consistency. While the proportions of the comminuted material and the oil may vary to a considerable extent, the boiler charge will normally consist of three or four parts of oil to five parts of material.

The boiler may be heated by a steam jacket or by internal tubing through which the steam is passed the initial heating being effected by steam which is maintained at a relatively low tempera.- ture, for instance by reduction of the steam pressure to 0.75 atmosphere to avoid violent boiling and the resultant carrying off of an excessive quantity of oil and solid particles. The temperature of the steam may be increased during the process until it reaches approximately 'C., corresponding to a pressure of about 2 atmospheres, or at least such a temperature that the material undergoing treatment is heated to about 60 C. It is sometimes necessary to again reduce the steam temperature below 1 atmosphere toward the end of the process owing to the gradual rise in temperature of the mixture. The temperature and pressure of the steam may be controlled in any convenient manner, for instance by throttling the steam.

Throughout the process the pressure on the material being treated within the boiler should be maintained as low as possible, a pressure of 0.2 atmosphere giving excellent results in the treatment of flesh. The temperature of the material may thus be maintained relatively low, it having been found that a temperature of more than 90 C. is unsatisfactory, principally because of the coagulation of the albuminous matter and the resultant encysting of a considerable portion of the material. As an example, if the material consists largely of liver,- the vacuum should be preferably reduced to an extent sufficient to ensure evaporation of the water in the material at 35 to 40 C. and the temperature of the oil should at no stage of the process exceed 50 C.

Preferably the evaporated water discharged from the boiler is condensed, any entrained oil is separated out. and the water may be purified for subsequent use in boilers for the rendering of oil from portions of the animal which are richer in fat. The separated oil may then be employed, preferably while still hot, in the treatment of a fresh batch of raw material, it being ordinarily necessary to introduce additional oil to replace that absorbed by the relatively lean material.

When the dehydration of the material has proceeded to such an extent that the water content of the material has been reduced to less than 10% and preferably about 6% or less, the material is withdrawn from the boiler and allowed to settle, the oil being withdrawn from the top, and the material being preferably pressed to remove the major quantity of the remaining oil. By this method the oil content of the material may be brought down to a practical minimum, experience indicating that a quantity of oil in an amount of about 10% to 12% of the material may be obtained and satisfactorily retained. With such an oil content the material may be easily transported pneumatically and may be delivered to tanks for storage.

It is highly desirable not only to comminute the material, but to stir the material during treatment thereof so that the water content may be evaporated rapidly and so that the various portions of the material will be uniformly dried, portions such as sinews and the like which are more hydrous can be dried to an extent sufficient to avoid the subsequent formation of centers of putrefaction in the mass. Furthermore, by means of constant agitation during the treatment the material as a whole may be maintained at the desired temperature to prevent the destruction of valuable products and the final water content of the mass can be more conveniently and accurately controlled. Conventional agitating means within the boiler may be employed for this purpose.

It is found that this method of preservation is principally effective for two reasons. Thus not only is the raw material sterilized by drying, but the oil which surrounds the individual particles of the dried material is sufficient to protect the material against moisture in the air, even though the greater portion of the oil has been removed from the material by pressing. The final product is in this manner sufficiently dried and preserved for transportation to distant places where it may be subjected to further manufacturing processes rendering it wholly suitable for the intended purpose. The process further results in a substantial decrease in volume of the material, the raw comminuted flesh beingfor instance reduced to about one-quarter of'its original volume and weight, whereby storage problems are simplified.

It is a significant fact that the oil in which the lean material is processed need not be of edible grade. Thus, it is found that an inferior unrefined whale oil, such as is readily available on board ship, can be used. Even though an ill smelling and tasting train oil is used, no difliculty is encountered in the subsequent preparation of the material for food stuff. It is also found to be quite possible to use flesh which is partially fermented or decomposed and has acquired a pulpy consistency by the destruction of the cellular tissue, whereas heretofore material in such condition has been thrown overboard whether fatty or lean.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A process for the preservation and storage on whaling vessels and the like of bones and comparatively fat-poor parts, such as flesh and internal organs of sea mammals which comprises dehydrating the raw material by heating with train oil under reduced pressure and to a temperature not exceeding 90 0., and subsequently separating excess oil from the material.

2. A process for the preservation of flesh poor in fat, bones, and internal organs of whales, seals and other sea mammals, which comprises comminuting the material to be treated, mixing the material with a comparable quantity of train oil, heating the mixture to a temperature suflicient to drive off moisture under a pressure substantially less than atmospheric, removing the major portion of the oil by draining and pressing, and storing the dried material.

3. The method of treatment of the carcasses of marine mammals such as whales, seals, or the like, which comprises separating from such carcasses the principal fat or oil containing portions, including the blubber, etc.; comminuting the remaining comparatively fat-poor portions including the lean flesh, the internal organs, and the bones; mixing the comminuted material with a sufficient quantity of oil to form a semi-solid mass; heating the mixture under reduced pressure and at a temperature not exceeding 90 G. until the major portion of the water content of the material is evaporated: and then removing the greater portion of the oil.

4. The method of treatment of the carcasses of marine mammals such as whales, seals, or the like, which is particularly adapted for use on shipboard, and which comprises separating from such carcasses the principal fat or oil containing portions including the blubber, etc.; comminuting the remaining comparatively fat-poor portions including the lean flesh, the internal organs, and the bones; mixing the comminuted material with a suflicient quantity of oil obtained from said fatty portions of the carcasses to form a semi-solid mass; heating the mixture at a pressure of the order of about 0.2 atmosphere and at a temperature not exceeding 90 C. for a sufficient length of time to evaporate the greater portion of the moisture in the material; and then removing the major portion of the oil.

5. The method of treatment of the carcasses of marine mammals such as whales, seals, or the like, which is particularly adapted for use on shipboard and which comprises separating from such carcasses the principal fat or oil containing portions including the blubber, etc.; comminuting the remaining comparatively fat-poor portions including the lean flesh, the internal organs, and the bones; mixing the comminuted material with a suflicient quantity of oil obtained from said fatty portions of the carcasses to form a semi-solid mass; heating the mixture to a temperature ranging from about 35 C. to 60 C. and

at a pressure sumciently reduced to effect the evaporation of water from the material at such temperatures, and continuing the heating for a length of time sufficient to reduce the moisture content of the material to less than 10%; and then removing the major portion of the oil by draining and pressing.

6. The method of treatment of the carcasses of marine mammals such as whales, seals, or the like, which is particularly adapted for use on shipboard, and which comprises separating from the carcasses the principal fat or oil containing portions including the blubber, etc.; comminuting the remaining comparatively fat-poor portions including the lean flesh, the internal organs, and the bones; mixing the comminuted material with a sufficient quantity of oil obtained from said fatty portions of such carcasses to form a semisolid mass; heating the mixture at a temperature not exceeding 90 C. for a length of time suflicient to evaporate the greater portion of the moisture in the material; and then removing the major portion of the oil.

JOHAN OLSEN NYGAARD.