. By appropriate methods of measuring the rate of penetration of salt into fish it was found that if absolutely pure salt is used a very rapid penetration is obtained, but that even small additions (from 1/2 to 5 per cent) of these salts of calcium and magnesium cause a very pronounced retardation of penetration. . Salt works by pulling all the water from each cell within a slice of meat. Search for more papers by this author. Stirring as usually done may cause a momentary increase of penetration by removing the film of dilute brine adjacent to the fish, but we may imagine that a new dilute, film forms again very rapidly. . . The agency which breaks down protein into these simpler substances is called an enzyme, and protein must always be so liquefied or digested by enzymes before it can be absorbed through membranes; hence the necessity of digestion in the stomach of animals preparatory to absorption of food through the intestines. Post-Harvest Fisheries Development: A Guide to Handling, Preservation, Processing and Quality. . It is known that the reddening does not attack fat fish. Inadequate salting, particularly of fish, has been associated with a number of outbreaks of foodborne botulism. . . c. Freezing. The principle by which salt (and other soluble substances) in concentrated solution extracts water is called osmosis. . This passage through the skin or membrane is called osmosis. The presence in or absence from the salt of certain impurities, notably calcium and magnesium compounds, the treatment of the fish, and the staleness of the fish, are factors which govern the permeability and have an important bearing on the preservation of fish by salt. . The range from 32 to 100° F. within which fish salting is usually done is, on the absolute scale, rather narrow (491.4 to 559.4° A. Salting is a traditional method of preserving raw fish throughout much of the world. . . . To them it may appear that salting fish is just salting fish, and "that's all there is to it." . While the former white. . It draws the moisture out of the flesh which inhibits the decomposing process. . The removal of water by means of salt is in some senses a truer dehydration than actual drying in air, for changes of an undesirable sort take place in air drying that are never corrected, while salting may be done in such a way that few changes other than removal of water are brought about. If cells are ruptured, as they often are by rough handling of the fish, autolysis rapidly decomposes the protein, and for this reason every bruise received by the fish during capture and subsequent handling results in the loss of so much protein during salting. . In eating qualities they were pronounced as good as or better than the best commercial salt herring from the Chesapeake Bay region. It was said above that protein is a colloid and that colloids do not diffuse through membranes. The tissues of fish consist mostly of cells. Saltpeter is, however, little used in curing fish, for the red color is undesirable, and hydrogen sulphide is rarely troublesome. . Facts already given indicate also that for other reasons salt free from impurity is better. The oldest methods to preserve fish are by salting or dehydrating the food. . . All sorts of possible preventives of rust are practiced or suggested for practice–such things as impermeable barrels, air-proof covering over the liquid, a reducing substance in the brine to absorb the oxygen, cool, dark storage, and the like. The salt should not contain impurities, due to iron compounds. . . We thus have water and salt outside, cell membrane between, and fish juice, or protoplasm, inside, and we desire to know what will happen and how we can influence the process to suit our needs. Salt thus causes a temporary precipitation or fixation of proteins in fish, to ascertain extent hardening the tissues and reducing the likelihood of changing. . Strong solutions of salt precipitate certain protein substances, different substances falling out successively from a mixture of dissolved proteins as the concentration of salt is increased. . Salt is also a preservative by virtue of its concentration. . This substance in the dry condition is nearly white and friable and contains enough nitrogen to command a handsome price as fertilizer if suitable for that purpose, but it may be more valuable for other uses. Comprehensive overview of salted fish production and products. . A method of curing fish embodying the improvements cited was tried in Florida on a small commercial scale with gratifying success. . . It is a further purpose of this paper, by showing what the few attempts made by science have done for the art, to convince and persuade those on whom the industry depends for its existence and progress that science can be expected to do a great deal more than it ever has done if it is energetically studied and applied. In 1918 research on this problem was undertaken under the immediate direction of the writer. . . This principle of osmosis is of almost universal application in nature and is used by men in the arts, but a good understanding of it is not common. . Salting is used because most … Since the perfectly clean fish decompose only slightly, it may be that only the blood decomposed in such cases as those given in the table, and that the decomposed blood pervading the otherwise sound tissue gave the appearance and odor of decomposition to the whole fish. Can these very pure salts be obtained commercially? So far in this paper discussion has been limited to the behavior of the protein or meat constituents of fish. . Salting is a process where the common salt (NaCl), sodium chloride, is used as a preservative that penetrates the tissue; hence slows the bacterial growth and deactivates the enzymes. Each cell is a bag of semiliquid, like the white of egg. If the stomach became empty because of temporary shortage of food or an injured mouth, the animal would die unless special provision were made to supply protein from some other source. Icing. . However, wrapping the product ~ a plastic bag reduces contact with the air. . . It shows that by the judicious selection of salt, not on the basis of its cheapness but on the basis of composition, one can produce a salt fish of almost any desired quality. . When autolysis is set in action by a bruise, do autolytic enzymes affect only the part bruised or do they escape and attack the uninjured cells, destroying them also? But many of the free fatty acids of fish oils readily oxidize on exposure to air and light, developing during the process a darker color and an unpleasant odor and taste which we call rancidity. . Fish curing is defined as the method of preserving fish by means of salting, drying, smoking and pickling.. a. Salting — Salt is the preservative agent used to lengthen the shelf life of fish and fishery products.This is used in almost all methods of preservation except in icing, refrigeration and freezing. All fishes have some fat, but the quantity is variable from species to species, between individuals of the same species, and within a single individual from season to season. We analyse global research on how methods of preservation and processing of foods affect the risk of developing cancer. This page was last edited on 22 January 2019, at 09:23. The relative concentrations govern the direction of flow and also the rate or quantity of flow. The nature of the dividing membrane will be considered first. . Plastic wrap. In brine salting, the entire or split fish is immersed in an aqueous salt solution. Low temperatures seem to increase the permeability of the cells, so that fish that have been chilled decompose more rapidly on being warmed than fish that have never been chilled, though as long as the fish remain on ice the low temperature may prevent the enzymes from doing their work. . Salting, drying, pickling, and smoking didn’t just preserve foods, but also transformed their taste, texture, and appearance. . Even here no chances are taken, for in most instances the casks of mild-cured salmon are held in cold storage at about 38° F. The selection of salt is principally on the basis of fineness, because a fine-ground salt is necessary to stick to the moist fish, only that which sticks to the fish being used dry. . . . Rusting consists of oxidation of fat after the latter has been split into free fatty acids. The fish variously known as mud shad or gizzard shad (Dorosoma cepedianum) is plentiful in certain parts of the country but is held in very low esteem because of its muddy, unpleasant flavor. It is essential that the salt (chemical: sodium chloride) is fresh. . . . This work is in the public domain in the United States because it is a work of the United States federal government (see 17 U.S.C. The muddy taste of the carp and other fish from muddy ponds and streams is believed by some to be caused by species of Oscillatoria, a blue-green alga growing in the slime of the fish; by others it is believed to be humic acid derived from the mud. Reddening is caused by two organisms, a spirochaete and a bacillus. Salting and drying are both preservation methods used in the production of koobi and therefore, it stores well in the freezer or at room temperature. In order to test the absolute necessity of the prescribed methods, other small batches were put up in different ways–by using cheaper salt, leaving roes in, and other such modifications. Salt is brought in contact with the exterior of the cell. Salting is one of the oldest methods of preservation of fish. A thick fish may spoil, while a thin fish may be saved; hence the splitting of fish. The experience gained in the work already done indicates that the recovery of valuable material from brine would not go well as a part of a small fish business but, having its own peculiar problems, would be more properly conducted as a separate business. . Salting is the preservation of food with dry edible salt. The combination of stale fish, high temperature, and pure salt brought about extraordinarily rapid penetration. Salting is a process where the common salt (NaCl), sodium chloride, is used as a preservative that penetrates the tissue; hence slows the bacterial growth and deactivates the enzymes. In coastal areas most of dried fishes processed from unsold fishes of the day. Salt-curing your own freshly caught fish not only saves room in the freezer, but it also connects you to an age-old preservation method. . . The actual food material of the fish–the cell protein–is still where it was, for practical purposes unchanged. The results of a part of this program were published.[3]. . The method of salting is free from cooling, but must be carrie… . Principles Involved in the Preservation of Fish by Salt, Appendix II to the Report of the U. S. Commissioner, ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––. This solution is separated from the contents of the cell by a cell membrane which is more or less semipermeable. . The most commonly used methods of salting fish are liquid brining and dry salting.In each case, the amount and rate of salt absorption are affected by a variety of factors. If we surround the cell with water, the inside will be more concentrated than the outside and water will go in. 9. The distribution of fat is also different in different species of fish. Calcium salts retained in the tissue increase the salty taste and make necessary a prolonged soaking out. By osmosis oxygen is taken from the air into the blood without any leakage of blood. . The salting preservation method primarily drains the skin. Salting is the preservation of food with dry edible salt. If the fish are directly exposed to air for a time, the fish "rust"–that is, the fat becomes reddened and rancid–and the value of the fish for food is very greatly impaired. . b. Now, these impurities, particularly calcium, have an acrid taste and greatly accentuate the “saltiness” of salt. . . In the centuries following the art continued, both in the Occident and the Orient, to play an important part in world economy. Analysis of Various Salts for Curing Fish. It may therefore be that salting fish immediately after capture would strike through the fish before autolysis gains any headway. During rigor mortis there is a decided development of acid that may very materially promote autolysis. . . There is one thing first to consider, make sure that the fish that is going to be preserve is new and still fresh. Some fish were held in the laboratory all day at a temperature of about 75° F. and toward night were salted in pure salt and put in an incubator at 100° F. By the next day they were struck through. . FLW can also be caused by a condition known as “putty fish,” which is the result of both heat and bacteria. When we cure foods with salt it can either be done by applying actual salt granules to the food or via a brine that the food is immersed in. Salt Your Fish . By virtue of its oxidizing power it may also oxidize hydrogen sulphide into sulphur dioxide and water; that is, a very foully odoriferous stuff to a substance which both bleaches and sterilizes. Salting of fish leads to diffusion of water out of the fish, causing removal of water, making the fish drier and thus helping in preservation. Dry salting is used to draw the moisture out of food, which helps to reduce the growth of unwanted bacteria. This is to prevent reddening. Dynamic Aspects of the Salting of Fish. It does take some time, so plan on at least a week, if not two, to ensure the fish are fully cured and dried. I hope that this is the … Studies on Salting and Drying Fish. The wet-salting methods (brine and pickle) are recommended for tropical applications, especially with fatty fish. By examination of numerous analyses of commercial brands of salt it was found that the salts of calcium and magnesium are those nearly always present as impurities. Very little improvement can be expected until the problem has been thoroughly investigated by scientific methods. Now, it may be either the blood or flesh, or both, in which the decomposition takes place. Various other chemicals are sometimes used in salt or along with it for various purposes. Automatic dry salting of fish fillets directly onto smoking grids. . The membrane, not being absolutely semipermeable, permits some salt to enter and the fish remains salty. Also, what was said about the loss of nitrogenous matter as a consequence of bruises applies to the mild curing of salmon. The ideal semipermeable membrane permits none to pass, but as membranes degenerate from ideal semipermeability to complete permeability they permit more and more of these dissolved things to pass through. . . 18. . Smoking and salting techniques improve on the drying process and add antimicrobial agents that aid in preservation. If the membrane is perfectly permeable to all constituents, water will pass through to the salt solution and salt will pass through to the water, and these movements will continue until the two sides are alike and then stop. . . . By combining all these factors into one method highly satisfactory results under the most adverse conditions have been obtained. . Free fatty acid has both taste and odor; in fact, our choicest fishes, such as salmon, shad, and mackerel, owe much of their peculiarly palatable flavor to the small amount of free fatty acid present. Department of Food and Marine Sciences, Instituto Tecnolbgico de Monterrey, Monterrey, Mexico. Some of the factors involved in salting of fish … The other class of substances, those that may pass through membranes and which on drying out crystallize in regular geometrical shapes, are the crystalloids. . e. With the use of additives or chemicals. In the various processes of salting or pickling fish the fish receive no preliminary treatment, or they may be gibbed, beheaded, split through belly, split through back, or cleaned perfectly by being cut open, scraped, and washed before the salt is applied. Now, most of these odoriferous substances are soluble in water or brine, and after the salting process would be found in the brine. II. . This substance contains some oxygen that may be given off to act as a sterilizing agent, and after the oxygen is given off ordinary salt or sodium chloride remains. The salt acts as a short term preservative in slowing down the proliferation and production of bacteria which causes spoilage and decay. e. With the use of additives or chemicals. . They are not only large of molecule but complex in structure. No unpleasant odor developed, and the fish upon being cooked and eaten were pronounced excellent. . When working with large quantities of fish, however, you may find rock salt the most economical. A temperature sufficiently high to destroy the enzyme stops it. . The discussion in this paper so far presupposes the desirability of preserving as far as possible the flavor and eating qualities of fresh fish. It was claimed that the sodium hypochlorite penetrates faster than ordinary salt. The reason fish have not been salted in the warmer parts of the country is that the process has not been satisfactory. Inadequate salting, particularly of fish, has been associated with a number of outbreaks of foodborne botulism. Specifically, such questions as follow should be answered: Once the permeability of cells has been increased by abnormally high or low temperature, does this increased permeability persist after a normal temperature has been restored? Boric acid is used for preserving cod against reddening. . Preservation of Meat by Salting Introduction: Salt-cured meat or salted meat is meat or fish preserved or cured with salt. Several brands of salt of the highest degree of purity are available both on the east and west coasts and at a cost not much above the price of cruder salt. . From the fresh fish rapidly deteriorates unless some way can be found to preserve it. These figures were obtained in the course of investigation on the recovery of valuable materials from old brine: Since all the nitrogen in the brine was calculated as protein, these figures are undoubtedly too high; but the bulk of the nitrogen is certainly of protein origin, so the figures may be taken to illustrate the point made. On the other hand, it is possible that the enzymes in the blood when present operate to decompose not only the blood proteins but the tissue proteins also. The results fully justified expectations in every way. In answer to this question it is necessary to refer to the principles of osmosis. In the case of cod and haddock, in which the muscle tissue is free from fat, the greater part of free water is extracted in the usual way by salt, later assisted by the pressure of piles or kenches, in which the lower layers are pressed by the weight of the upper layers in the kench, and finally by drying out of doors or in artificial drying tunnels. Insects and pests typically cause waste, as well as quality loss. Salting and other methods Foods can be preserved and processed in a number of ways prior to consumption. Both temperatures are high for salting fish, and the test is correspondingly severe. This process would be unthinkable on the basis of the customary salting methods where there is in the end an excessive saltiness or flatness of flavor, but the mild, sweet fish prepared by improved technique and pure salt is a much more promising possibility for canning. . By osmosis our food is taken from the intestines to the blood without any communicating opening. 16. Oxidation of fat brings about colour change in dried products which can affect taste (rancidity) and the selling price of products value. Perhaps the two views could be entirely reconciled, but the actual chemical compound or compounds responsible for the unpleasant flavor seems to be removed by the brine. . If required, printed copies of this open learning module may be purchased from . If the calcium is held by the tissues at the time of soaking out while the salt is removed, then after soaking there is a much greater amount of calcium present in proportion to the amount of sodium than there was in the original salt and a correspondingly more acrid “salty” taste. . There is every reason to expect a good future for the salt fish industry, but progress must be made. . Ideal semipermeability with respect to particular dissolved substances has been achieved and is found in living organisms. Less than 25 years after Shakespeare wrote that play the Plymouth Colony landed in America and brought with them the arts of sousing and pickling fish. Fish are salted whole (if they are small), split or cut into pieces prior to salting. The principles of osmosis here very briefly stated are the fundamentals of the art of salting fish. It was practiced by the Phoenicians and Greeks and was brought to a high degree of perfection by the Romans. With highly improved technique in salting, the undesirable flavors might be removed by curing and soaking out before canning. The kidney, a very bloody organ inclosed by a membrane against the backbone, must be scraped out before the fish is washed. . . Repeated efforts to salt alewives on the St. Johns River in Florida previous to 1920 uniformly resulted in failure. . . It was pointed out that calcium and magnesium salts combine with the fish protein to form a white, hard flesh. The 40 per cent of the dressed fish contains besides water much protein or valuable nitrogenous food. The climate is excessively warm, and there is an abundance of fish (alewives) adapted to preservation by pickling in a region where an industry might well be built up and where repeated efforts to salt fish in the past had failed. . Overview of causes of and solutions to fish loss and waste. . . It should also be obvious that since the very purpose of using salt on fish is to extract water the addition of water at the beginning simply supplies just so much water to the salt and satisfies the affinity of salt for water to that extent. A determination of amino acid nitrogen was taken as a measure of decomposition–the more of the amino acid nitrogen present the greater the amount of decomposition. The quantity of protein that escapes into the brine is highly variable, for reasons that will appear later. If these bacteria grow fast enough, they may spoil the fish before the salt strikes in to stop their growth. The difference in liquid level would exert a pressure called osmotic pressure. The fish were preserved successfully, and none that had been handled in the prescribed way spoiled. The method of Chilling and Freezing; if the … The implication here is, of course, that pure salt itself would be a poor supporter of the bacteria. Salted Fish. 17. Salting and Pickling processes in food preparation and preservation. The blood is not removed, the fish rather being allowed to cure in its own blood pickle, a distinctive flavor thereby being imparted. Therefore it should not be expected that any purchased lot of salt would conform exactly to the composition shown here. It takes from one to two full days in warm weather for the salt to penetrate the thicker parts of the fish, and usually only large fish become puttied. . It is a low cost form of fish preservation. . Every hundred pounds of brine that goes overboard contain about 26 pounds of salt, to say nothing of the valuable nitrogenous matter that the brine has extracted from the fish. How Does Salting Food Preservation Work? . It is of the greatest importance that research work be undertaken for the purpose of discovering the conditions under which the cell proteins are digested and pass out and for ascertaining the conditions under which these processes may be arrested. . Stale fish–that is, fish whose cell membranes have “died”–are more permeable than fresh fish. Calcium and magnesium compounds in addition to retarding penetration cause a whitening and hardening of the fish. If fish is cleaned in this manner and salt of a very pure quality applied in the dry condition, it is astonishing not only what severe temperatures it will stand, but also how excellent it is when cooked. The product portfolio includes salting equipment, salting machines, tubs and custom made packing tables.
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