DE1195149B - Process for making dried potatoes - Google Patents

Description

Method of Making Dried Potatoes The invention relates to a method for producing dried potatoes, in particular a method for making dried potatoes, which have a better moisture absorption. The parts and percentages given below relate to the weight, unless otherwise stated.

There are already various methods of making pulpy potatoes known in drained, pre-cooked form. In this process, the potatoes cooked, made into a paste and subjected to further treatments, so that if necessary dehydrated products arise in subdivided form, e.g. B. as flakes or grains. According to the invention, dried, cooked and pasted potato products are made which have better properties, especially better water absorption demonstrate. That is, when the dried products are prepared for use again then they absorb more water than those produced by conventional methods Products. This means that a unit weight of dried potatoes, according to of the invention, generally a larger amount of reconstituted, pulpy potatoes than the usual products. So z. B. according to Invention dried products are made that are up to 25 to 35 0/0 more of reconstituted pulpy potatoes than the same weight common products.

The invention relates to a method for producing dried ones Potatoes, in which the potatoes are cooked, then made into a pulp and then are dried, according to which the advantageously sliced roll potatoes Soaked in water before boiling until their weight is due to water absorption by 7 to 25%, preferably by 7 to 10%, based on the weight of the raw potatoes, increases.

The theoretical reasons for the effect of what was previously made Soaking on the water absorption of the final product cannot be explained however, it has been found that the desired practical effect is obtained. For a maximum increase in the water absorption of the end products, the potatoes can can also be soaked again after cooking. Through this additional Soaking will reabsorb the added water that is removed from the fabric of the Potatoes may have been expelled during the cooking process.

When carrying out the method according to the invention, the potatoes first prepared in the usual way, washed, peeled, cut and then preferably in parts, e.g. B. in slices, schnitzel or the like., Cut up. the Potatoes are then soaked in water until their weight is around 7 to 25%, preferably by 7 to 10%. Depending on factors such as the size of the pieces, the variety of types of potatoes, etc., The duration of the soaking can be around 1 to 4 hours to get the desired one Effect achieved. The soaking process is expediently the process in which the potato tissue is soaked in sulfite to add color and taste during treatment and storage of the product. The water can therefore preferably be a little Amount, e.g. B. 0.02 to 0.1%, sodium sulfite or bisulfite contain.

This addition of sulfite can be in place of or in addition to a Sulphitation take place in other process stages. These embodiments of the method are, as far as the product manufactured afterwards not for delivery in areas outside of the Food Act is currently determined on the basis of the ordinance on the Approval of foreign substances as additives to food prohibited. Afterward the potatoes are cooked during the soaking process. The water in which the potatoes can be cooked, if desired, a small amount of sodium sulfite or Contain sodium bisulfite. Cooking can be done in any way. The cooked potatoes are then prepared using one of several methods that lead to the production of dried potatoes in subdivided form. Regardless of the type of product that may be produced, those given above are obtained Advantages. So the boiled potatoes z. B. paste and after known Process for producing dehydrated flakes or grains. Working method for converting pasted potatoes into such products are known, and it can any method can be used. Working method for producing granular products and a method of making flakes are known.

A preferred method for the preparation of potato granules according to the invention is described below.

The raw potatoes are first pretreated, washed, peeled, cut and chopped. The pieces are then cut into slices, which can have a thickness of 3 to 25 mm. Instead of chopping the pieces these can also be cut into other, easily processable parts. the Potato chips are then soaked in water as described above and the soaked potato pieces are then boiled. This cooking can be carried out in the usual way, e.g. B. by the fact that the shredded Potatoes (about 19 mm thick) in boiling water or in steam at the same temperature, (100 ° C) about 20 to 30 minutes. According to a preferred method is cooking at temperatures between about 80 and 100 ° C at normal pressure about performed for a period ranging from about 100 to 750 minutes at 80 ° C to shortened to about 5 to 10 minutes at 100 ° C roughly along a logarithmic curve.

After the potatoes have been cooked, they can be prepared in a manner known per se recently soaked in water so that the moisture is absorbed again lost during cooking as described above.

After boiling or after soaking again, the potatoes will be conditioned directly or after a slight increase, being the least possible mechanical force is applied which is necessary to keep the tissue of the potato is broken up. In this conditioning stage, the potatoes are treated in such a way that that their pasty structure is eliminated and that they are made friable. The conditioning can be carried out above freezing temperature, e.g. B. at about 32.2 ° C down to -1.1 ° C, or below freezing temperature, e.g. B. from about -1.7 ° C down to -23.3 ° C. The conditioning is preferably carried out under static conditions, d. that is, the potato material is not subjected to any mechanical action. The time required for conditioning depends on the temperature, and it decreases with falling temperature. With conditioning above freezing temperature the time for the treatment takes about I / 2 to 4 hours while the material is conditioned at a temperature substantially below freezing once it gets frozen.

The conditioned potato material is then made into a paste. If the Freezing temperature conditioning is carried out, then the potato tissue must of course, be thawed before boarding. To speed up thawing can a stream of warm air can be directed onto the frozen material. The joining process can be carried out in such a way that the potatoes are pressed between warm rollers, that they are pressed through a sieve or by some other conventional method for battering of the potatoes. Pushing through a coarse sieve, e.g. B. through a sieve with A mesh size of 3.36 mm is preferred, as this is the case during this process a joining is achieved and at the same time parts of shells, eyes and others Waste can be easily removed from the potato material. While boarding various additives can be incorporated into the mass. About color and taste To preserve it, a small amount of sodium sulfite or bisulfite can be added. Generally enough sulfite is added that about 200 to 500 ppm (parts per million) of 502 on a dry basis, including the previous one Work processes incorporated sulphite are present. Smaller proportions of fat stabilizing Antioxidants, e.g. B. nor-dihydroguaretic acid, butylated oxyanisole, butylated Oxytoluene and the like may be added to make the natural one rancid Fat content in the product is avoided during storage. About water absorption to increase and decrease stickiness become edible dispersants added, e.g. B. Monoglycerol esters of long-chain fatty acids can be incorporated into the pulp will. Other substances that can also be added are food additives, such as table salt, whole milk solids, non-fat milk solids, and the like.

The pulpy potatoes are partially dried to keep their moisture content to about 50 to 75%, preferably to about 60%. A partial drainage can be done by any conventional method. A preferred method consists in the fact that the pulp is spread in a thin layer and a stream of warm air exposed to around 26 to 66 ° C while being made fluffy at the same time is, for example, by rotating paddles or blades. It can A shaker dryer can also be used, in which the material is placed on a sieve that is shaken or vibrated while a stream of warm air is applied the sieve is straightened.

The conditioned material is then granulated and applied to the critical Moisture area dried. The granulation and drying is either simultaneous carried out or repeated several times in immediate succession Operations. (If the conditioning is carried out below freezing temperature, then the slurry is thawed before granulation.) At this granulation stage the pulp is divided into particles; which no more than about ten individual cells contain, preferably unicellular particles, and this is done by separating a cell from the other cells, whereby the individual cells should not be torn. If this is done, then when the product is restored, it would become a pasty and unsavory mass. The granulation can thereby be carried out with success that the mass is repeatedly gently compressed and that slight shear forces exercised on them. A coarse potato material still present after granulation can be returned to the conditioning stage.

The granulated potato material will eventually continue to form dehydrated dry granules. This final drainage can be in any Way to be carried out. For example, the granulated potato material can after Processes are dried in which work is carried out in the fluidized bed. This is done the granulated potato material placed in a container with means is equipped by the weak hot air currents up through the material bed are blown and through which this bed while drying in the fluidized state is held. An apparatus of this type and a method of using it Apparatus for dewatering moist potato particles is in N e e1 et a1. (Food Technology, 1954, Vol. VIII, pp. 230-234). To maintain the state of the vortex to further convey the product in the early stage of the drying process the fluid bed dryer can be continuously vibrated or shaken or it can mechanical stirring devices can be used. The granulated potato material however, it can also be dried in pneumatic dryers, as is the case, for. B. from Olson et al. (Food Technology, Vol. VII, pp. 177 to 181 [1953]). This device consists essentially of a vertically arranged guide. Hot air of around 100 to 200 ° C is blown upwards at high speed (e.g. at about 305 m / min.) pressed through the guide, and the friable, granulated Potato material is introduced into this air stream. As soon as the airflow Material upstairs, it is dried. At the top of the lead is a conical divergent diffuser provided so that once the flow is up in enters the diffuser, its speed is gradually reduced. A deflector is arranged above the diffuser, through which the now decelerated flow after is deflected down, so that the dried potato grains out of the air stream leak and can be easily separated from the moisture-laden air. According to a preferred method, the final drying is carried out, while the potato material is repeatedly gently squeezed and light shear forces is exposed. After the final drying, the product has a water content from about 5 to 8%, preferably about 6%.

The preferred method as described above enables the production of potato granules with a high water absorption capacity, which when added pulpy potatoes restored by water with a desirable floury i results in structure that are neither pasty nor contain lumps. Important in this Relationship is the fact that the potatoes have a low blue value, a sign that the cells are negligible during the treatment Extent t were torn. The products can therefore even be mixed with boiling water be restored and result in pulpy potatoes with the desired, floury structure. If there was any noticeable rupture of cells, then if you reconstituted it with boiling water you would get a pasty mass. It is also noteworthy that the products are generally natural, qualitative high quality potato flavor and retain their color.

The following examples serve to illustrate the invention: In the Examples were blue index products according to the method of M u 11 i n s et a1. (Food Technology, Vol. 9, p. 393) checked, with a base of 21/2 g dry solids was assumed. This determination provides a measure for the release of free starch from cells and a high value means one larger amount of free starch. Another test was the water absorption of the products measured according to a method that is different from that of Potter (Jour. Ag. and Food Chem., Vol. 2, p. 516, 1954) is modified. at this test is the volume of granules dried per unit weight of the restored pulpy potatoes measured. In this case means a higher value a better product, as more pulpy potatoes from a standard quantity Dry material can be formed. Example 1 Idaho Russet Burbank potatoes washed, peeled, cut to size, cut into pieces of 12.7 - 12.7 - 19 mm and washed to remove the free starch.

The potato pieces were in. At room temperature for 2 hours Soaked water containing 0.02% sodium bisulfite. The weight gain as a result the absorption of water was 7%.

The soaked potatoes were boiled in water (the 34 g sodium bisulfite per 68 kg of water), with boiling at 88 ° C for 60 minutes.

The boiled potatoes were then divided into three parts. the Sample A potatoes were frozen at -12.2 ° C. The potatoes of the sample B were soaked in water at room temperature for 20 minutes and then at Frozen -12.2 ° C. Sample C potatoes were 11/2 at room temperature Soaked in water for hours and then frozen at -12.2 ° C. All three Samples were then treated as follows: The potatoes were placed in warm air thawed, pulped, spread on sieves and an air flow of about Exposed to 37.8 ° C so that they were partially drained. After an hour and a half after continuous treatment, the moisture content of the potatoes was about 70%.

The partially dehydrated potatoes were then granulated in a granulating device, the collecting device being designed in a special way. The shaft was rotated at six revolutions per minute and air at a temperature of 121 ° C. was blown through the device. After about 20 minutes the process was finished and the dried granules (about 20% moisture content) were removed from the collector. These granules were completely dried in a fluidized bed dryer, resulting in granules with a water content of about 6 %. The products were tested for water absorption by the method of Potter (Joür. Ag. And Food Chem., Vol. 2, p. 516, 1954). This test determines the volume of the reconstituted pulpy potatoes, which is formed by one unit weight of the dried granules. In this test, higher values mean better products, since more pulpy potatoes are formed from a standard amount of the dry product.

The following results were obtained: Water absorption, milliliters restored porridges per gram of granules Sample A .................. 6.8 Sample B .................. 7.0 Sample C .................. 7.5 In a non-soaking comparative test, the product had a water absorption of 6.4 ml / g.

Example 2 Idaho Russet Burbank potatoes were pulped, peeled, cut to size, cut into slices 3 mm thick and washed, so that free starch was removed.

The chips were in water for 21/2 hours at room temperature soaked. The weight increased by 17% due to the absorption of water.

The schnitzels were boiled in water at 88 ° C for 80 minutes.

The cooked schnitzels were forced through a two-mesh sieve (clear mesh size 10.9 mm) and divided into two samples: A. One sample with the coarse pulp product containing a large proportion of lumps of about 9.5 mm in diameter was spread in a sheet 12.7 mm thick and frozen at -12.2 ° C.

B. The other sample was mixed in a planetary mixer for 1 minute, whereby a fine pulp was formed, containing only a few lumps with a diameter of 1.59 to 3.17 mm contained. The slurry was also spread in a layer 12.7 mm thick and frozen at -12.2 ° C.

Both samples were then thawed and made into a paste by putting them through a twin roll apparatus at 49 ° C were performed, the distance between the Rolls 0.38 mm and the speed of rotation of the rolls one revolution per minute cheat.

The pulped potato material was then sieved in dried in a housing dryer, the mass loosened by hand from time to time and the temperature of the air in contact with the slurry was 45 ° C.

The following results were obtained: Water absorption, milliliters restored porridges per gram of product Sample A ........... .... 8.0 Sample B .................. 7.2 I. In a comparative experiment in which there was no soaking but the pulping was carried out as in sample B, the water absorption of the product was 6 ml / g.

Example 3 Idaho Russet Burbank potatoes were washed, peeled, but not cut to size, cut into pieces of 12.7 - 12.7 - 19.1 mm and washed to remove free starch.

The cutlets were soaked at room temperature for 2 hours, the weight gain being 8%.

The schnitzel was boiled in water at 88 ° C for 60 minutes, the water containing 0.1% NaHSO3.

The cooked schnitzel was spread out in a layer on sieves and frozen at -12.2 ° C. The frozen potatoes were then thawed by exposed to a stream of air at 37.8 ° C.

The thawed potatoes were then placed in a planetary mixer 1 Mix for a minute and then pass through a 6-mesh sieve (mesh size 3.36 mm) pressed. Fragments of peel, eyes, and crushed tissue got caught in the sieve and have been removed.

The slurry was then partially dried on a conveyor belt that was equipped with two rotating blades, so that a light pressure and light Shear forces were applied to the potato material. During the stay on the conveyor belt, the potato material was in contact with an air stream of 100 ° C and as soon as the material reached the end of the tape it was turned into a upward draft of air, which had a temperature of 127 ° C. The mashed potatoes were guided over the conveyor belt 6 times over a period of 20 minutes, and the moisture content of the product was 60%.

The partially dried slurry was placed in a granulator granulated, with the slurry exposed to a current of 66 ° C air, and the shaft rotated at a speed of two revolutions per minute. In about 20 minutes it was the material was granulated and its moisture content was 35%. The editing was continued until the moisture content of the product decreased to 20% was then finished drying in a fluidized bed dryer. The dehydrated granules had a blue index of 2 and a water absorption of 7 ml / g.

Claims (6)

Claims: 1. A method for producing dried potatoes, in which the potatoes are boiled, then made into a pulp and then dried are, characterized in that the advantageously sliced raw potatoes Soaked in water before boiling until their weight is due to water absorption by 7 to 25%, preferably by 2 to 10%, based on the weight of the raw potatoes, increases. 2. The method according to claim 1, characterized in that the potatoes be cut into slices 3 to 25 mm thick. 3. The method according to claim 1 or 2, characterized in that the potatoes after cooking in per se known way again in Water to be soaked to the at Boil to replace lost water. 4. The method according to claims 1 to 3, characterized in that the boiled potatoes are lightly pasted or pressed through and then 1 / z to 4 hours at a temperature in the range from -1.1 to -I-32.2 ° C. 5. The method according to claims 1 to 3, characterized in that the boiled potatoes are lightly battered or pressed through and then cooled for a short time to a temperature between -23.3 to -1.7 ° C will. 6. The method according to any one of the preceding claims, characterized in, that the pulped potatoes to a moisture content of 50 to 70 percent by weight, preferably 60 percent by weight, dehydrated, in small pieces further divided or granulated and then up to a moisture content of 5 can be dried up to 8%. Publications considered: German patent specification No. 896 448; British Patent No. 566,828; "Chemisches Zentralblatt", 1961, P. 2126.