GB2197175A - Producing potato products - Google Patents

Abstract

The process comprises heating whole unpeeled potatoes until they reach an internal temperature of at least 145 DEG F, for example a temperature in the range 145 to 195 DEG F, which destroys the color forming factor, but for a time which results in only partial baking or cooking of the potatoes such that they maintain their structural integrity and can be subsequently peeled; cooling the partially heated potatoes; and cutting the potatoes into pieces. <IMAGE>

Description

SPECIFICATION Producing potato products This invention relates to processes of producing potato products and the resulting products.

Background of the Invention Humans probably consume more potatoes than any other food. Potatoes are generally eaten in conjunction with other foods. For example, we eat meat and potatoes, fish and chips, hamburgers and french fries, breakfast of eggs and bacon with hash brown potatoes and a multitude of other potato combinations.

When utilized in the home there is no real problem in handling potatoes. It is known that when potatoes are peeled they will discolor so the peeled or sliced potatoes are placed in water until used. Since potatoes are promptly used at home no problems are involved.

In the last decade there have been many changes in food distribution and consumption. Now far more persons eat at restaurants and fast food service establishments. There are thousands of food franchise outlets which utilize potatoes. Because potatoes are bulky there are disadvantages in having these outlets buy bags of potatoes and peel them right at their facility. As a result a new business developed to process potatoes.

There are many potato processors in the United States and other countries. They purchase bulk potatoes, peel them and then slice them to form french fries or they may slice the potato into some other form suitable for use. The potato processors found several serious problems in the handling of potatoes, especially in supplying the potatoes to the individual outlets in a perfect condition. This became even more apparent when the potato processor began to supply packaged potato products, refrigerated or frozen, to the outlets, including supermarkets.

The intact whole potato is comparatively stable. It can be shipped in bulk or in bags and be stored under various conditions and still retain its shape and form and be suitable for use.

However, when the same potato is peeled and sliced the situation becomes completely different.

The peeled sliced potato discolors rapidly when exposed to air and becomes black. The slices weep, with moisture coming to the surface and giving the slices the appearance of wetness.

When the slices are frozen these changes are accelerated and the discoloration occurs even more rapidly with substantially more wetness at the cut surface.

The potato processor, to overcome the problems of discoloration and wetness, employed additives which were approved and established when this industry first developed. It was learned, for example, that sulfites retard or prevent discoloration at the sliced potato surface and that phosphates, especially pyrophosphatei aid in water-binding and also in secondary color reactions relating to after-cooking discoloration and nonenzymatic browning. Potato processors used sulfites in the manufacture of precut potatoes, usually refrigerated, when delivered to a restaurant or franchise outlet.

Potato processors also found they could eliminate the use of sulfites by partially deep fat frying the sliced potatoes, freezing the product and shipping the partially fried product to outlets.

The deep fat frying destroyed the color forming factor but in so doing increased very substantially the caloric value of the product. Blanching of individual pieces to destroy the enzyme systems is used for many applications.

With the public scrutinizing the usage of additives in foods, all additives are considered suspect so food processors when possible desire to advertise and state that their products are "natural", that is, that no additives are used in their manufacture. Of particular concern to the public is the use of sulfites which are banned in many vegetables. The banning of sulfites in potatoes would add an additional problem to particular potato processors in supplying high quality, cut, color free potato products.

Description of The Invention According to the invention it has been found that heating potatoes to partially bake them destroys the color forming factor while still retaining firmness and structural integrity of the potatoes. Before or after peeling the partially baked potatoes can be cut into pieces in the form of slices, french fries, grated, diced and other forms and the cut surfaces do not discolor. The potato pieces have enhanced water binding qualities. The potato pieces can be packaged, refrigerated or frozen and then used later for making french fries, hash brown, American fries, shoestring potatoes, potato pancakes and other types and forms of potato products.

In practicing the invention potatoes can be partially baked or cooked by heating them batchwise or continuously to an internal temperature of about 145 to 195"F within a reasonable time.

An internal temperature of 135"F is too low to destroy the color forming factor while a potato internal temperature above 200"F yieids a potato with minimal structural integrity so that it does not peel too well nor can it be cut into slices which maintain good shape and form upon handling. A more specific range of internal temperature is 1 50 to 175"F and a preferred internal temperature range is 150 to 165"F.

An air temperature of about 200"F to 425"F is suitable for partially baking the potatoes but from a commercial standpoint the heating temperature used will probably be around 4000F. A baking time, usually ranging from 15 to 40 minutes, will vary with the weight of the potato and its shape. Sufficient heating time must be allotted to partially bake or cook the potato to the extent necessary to achieve the goals of the invention. If the baking time is too short and/or the temperature too low the color factor will not be wholly destroyed nor will the potatoes be adequately cooked. If the baking time and/or temperature are too long the potatoes will be over cooked, not peel well nor can they be cut into good shaped slices.

By the use of this invention one can pre-cut potatoes and maintain them in perfect condition for 10-14 days of storage under refrigeration. No additives are required and no precautions need be taken to avoid air during packaging. The potatoes may be diced to 1/4", 1/2" or 1" or larger size. The potatoes may be sliced or cut in form of french fries or may be grated. By utilizing this invention one will see a marked increase in the sale of precut fresh potatoes to restaurants, institutions, etc. and will also see the product in smaller packages sold in the supermarkets in the refrigerated section much like other vegetables sold in this area.

The stabilized structured potatoes of this invention will result in substantial changes in the processed frozen potato products now being sold in the supermarkets, institutions and to various franchise outlets. The quality of certain products will be improved. The usage of deep fat frying for potato products sold in the frozen food counter will be cut back. The package label declaration need simply state - Potatoes-except when spices or flavorings are added. Frozen potato products provided by this invention can be combined with other vegetables in unit packages.

After being partially baked and cooled, peeled and sliced according to the invention the slices can be frozen. The freezing eliminates surface stickiness which the slices may have, especially if the potatoes are baked to a high internal temperature of about 185"F. The freezing process thus supplies a desirable complementary action in producing a product with superior properties. The frozen product can be marketed as such since the freezing does not reduce the high quality of the product. Also, when thawed the product does not discolor, become wet or lose its form or shape. The product can be placed frozen in an oven and warmed until thawed and fully cooked.

Additionally, the frozen or thawed product can be cooked in oil to make french fries, hash browns, American fries, shoestring cakes and potato pancakes using conventional cooking procedures.

After partially baking, cooling and cutting the potatoes into the desired shape, the potatoes can be partially dried prior to packaging and storage under refrigeration or freezing. A partial drying can reduce the weight by 20-40% without obvious physical shrinkage. Partially dried pieces could be continuously fed into a deep fat frier with substantial improvement in production rate and costs of manufacture, such as of potato chips.

Complete drying can lower the water content until the potato pieces contain about 8 to 15% water by weight. The potato pieces can be dried and packaged and marketed without the need for refrigeration. A skin develops on the potato pieces upon drying. The skin is largely resistant to moisture. When the dried pieces are heated in an oven to a high temperature, or immersed in a hot oil, the pieces puff. When heated in air, a low-calorie puffed potato product is obtained.

When rehydrated in water the formerly dried pieces take on the appearance of cut fresh potato pieces which when simmered in boiling water to complete cooking can be mashed with milk and butter added to yield mashed potatoes.

The potato processor had far more complicated problems than other processors involved with other vegetables such as peas, carrots, beans and cauliflower. These processors simply wash the vegetable, make the proper cut, package and freeze the vegetable. The label declaration for the products simply states: peas, carrots or beans, etc. since no additive has been included.

In contrast to processors of other vegetables, the potato processors do not offer a raw vegetable because to overcome the problems involved in handling cut raw potatoes they heated the potatoes in oil, heated in hot water or steam, added sulfites, and in some cases added special starches or gums and phosphates for some applications. This is illustrated by the following three labels taken from frozen hash browns, patties and pancakes, available at a supermarket: 1. Ore Ida Microwave Hash Browns, two shredded potato patties. Ingredients: potatoes, vegetable oil shortening (contains palm oil or partially hydrogenated soybean oil), salt, natural flavoring, dehydrated onions, dextrose, disodium dihydrogen pyrophosphate (to retain natural color).

Ore-lda Foods, Inc., Boise, Idaho, U.S.A. 83706 Product of U.S.A.

Heinz 2. Jewel Shredded Hash Brown Potatoes Ingredients: potatoes, salt, disodium dihydrogen pyrophosphate (to promote color retention), dextrose.

3. RusEttes Potato Pancakes Ingredients: potatoes, whole egg, textaid (modified food starch), flour, non-fat dry milk, palm oil, partially hydrogenated soybean oil, blend of animal fat and vegetable oil (beef fat, soybean oil, cottonseed oil), onions, salt, green onion flakes, spices, xanthan gum, water.

Packed by Idaho Frozen Foods, Twin Falls, Idaho 83301.

By using the heat treated potatoes of this invention the potato processors could simply package and freeze the grated or sliced potatoes. The label declaration for such a product need only state: potatoes. The restaurant and the housewife could then use the product by following some simple recipe for hashed brown potatoes, such as the following recipe from a Betty Crocker Cookbook: Combine 3 cups chopped cooked potatoes with 3 tablespoons of flour, 1 tablespoon of minced onion, a quarter cup of milk, 1 teaspoon of salt and 1/8 teaspoon of pepper. Heat 3 tablespoons of fat in a heavy skillet, pack potatoes in firmly, brown over low heat on underside (20 minutes), fold over like an omelet.

Serves 4.

By using the invention the need for so many additives, now being used in hash browns and potato pancakes, such as disodium dihydrogen phosphate, modified starch, xanthan gum and excess amounts of vegetable oils used in cooking could be eliminated. For some special requirements a particular additive may still be helpful. Spices, seasonings, dehydrated onions, and paprika could be used if desired.

A very popular french fry sold in supermarkets has a label declaration as follows: Ore Ida Crispersl Ingredients: potatoes, vegetable oil shortening (contains palm oil or partially hydrogenated soybean oil), dehydrated potatoes, salt, glycerol monostearate, xanthan gum, dextrose, hydrolyzed vegetable protein, disodium dihydrogen pyrophosphate (to retain natural color), dehydrated onions, sodium sulfite and sodium disulfite (to retain natural color), citric acid, and B.H.A. (to retain natural freshness).

US Patent No. 4,082,855 Ore-lda Foods, Inc., Boise Idaho 83706 Heinz By utilizing the invention the potato processors can largely eliminate the use of gums, sulfites and many other additives. The Food and Drug Administration has already banned the use of sulfites for many vegetable treating applications so it is likely only a matter of time before it bans the use of sulfites in potatoes.

Applicant's invention pertains to a method for potato processing which eliminates the need for (1) immersion of cut pieces in sulfite solution or other additives (2) blanching individual pieces with hot water or steam and (3) the need for oil-blanching potatoes.

By utilizing this invention applicant improves and simplifies almost all factors of potato processing. The essence of this invention relates to the fact that the enzyme system is deactivated in the unpeeled potato prior to slicing or cutting. In the prior systems of potato processing, after washing, peeling, and trimming a potato may be cut into as many as 4 to 1000 pieces and each piece is treated separately by (1) sulfite solution or (2) water or steam blanching or other heating, or (3) cooking in oil. During these various procedures there is (1) a moisture uptake and cell destruction in water or steam blanching, (2) the addition of sulfite which is being looked at with much concern by the Food & Drug Administration, and (3) the addition of fat which changes the potato flavor and increases caloric intake.In the practice of this invention (1) no moisture uptake occurs, the potato remains firm with excellent structure (2) there is no need for sulfites or other additives and (3) there is no need for deep fat frying to prevent discoloration unless deep fat frying is desired as in French-fried potatoes. In summary, it is much simpler to treat the whole potato than to deal with each individual piece.

A host of patents pertaining to potato processing have in common certain initial processing steps which include sorting, peeling, trimming and then cutting the potatoes into strips or other size pieces. The strips or pieces are then treated in various ways to prevent discoloration before being converted to the final product.

We have here a basic fundamental difference in processing between applicant's invention and the prior art. In applicant's invention the whole potato is partially baked, which destroys various enzyme systems, thus imparting stability and, in addition, the partially baked potato has firmness and structural integrity with enhanced water retention properties. All these qualities are imparted to the potato before the potato is peeled, followed by cutting it into strips or other sized and shaped pieces. Since the strips or pieces have already been stabilized no further stabilization treatment is necessary.

The following examples are presented to further illustrate, but not limit the scope of, the invention.

Example 1 Two Russet potatoes were placed in a toaster oven with the thermostat set at 225 F and the potatoes were left in the oven for nine hours. The internal temperature of the potatoes upon removal was 165"F. The potatoes were allowed to cool overnight exposed to room temperature (70"F) air.

The following morning the heat treated potatoes were cut and diced into pieces the size of french fries and the same process was followed with unheated peeled potatoes (control). The cut potatoes were allowed to remain on a kitchen table overnight. The following day the control potato strips were observed to be very dark to black in color while the partially baked potato strips were white with no color change.

The partially baked potatoes had undergone substantial gelatinization.

Example 2 Example 1 was repeated except that the heating time in the toaster oven was reduced to five hours. The internal temperature of the heated potatoes was 165"F. The whole potatoes after heating were very firm and estimated to be 50% cooked. The partially baked potatoes cut well into strips. The color of the cut strips remained white upon exposure to air. The potato strips were put in hot oil and fried in typical fashion to American fries.

Example 3 Example 1 was repeated with the thermostat on the toaster oven lowered to 200"F and the potato exposure time in the oven reduced to two hours and fifteen minutes. The potatoes internal temperature when removed from the oven was 160"F. The potatoes were about 40% cooked. After cooling to room temperature (70"F) the partially baked potatoes were sliced. The slices showed no discoloration upon exposure to air and the slices remained dry with no sign of surface wetness. In contrast, fresh potato slices went off-color rapidly and the slices felt wet rapidly. The slices from the partially baked potatoes were very dry.

When the slices of the unheated potato were placed on a napkin the paper became soaked with moisture within one hour and the color of the slices became dark and brown. When this was done with the partially baked potato slices the napkin remained dry and the color of the slices white.

Slices 1/8 inch thick of the unheated potato and partially baked potatoes were allowed to dry at room temperature (70"F) overnight. The unheated potato slices were almost black in the morning and they had a chalky bite while the partially baked potato slices were white and their surface was glassy, quite hard and vitreous. When the dried glassy slices were added to hot oil they expanded or puffed in a matter of seconds to two to three times their initial volume. The expanded product was very tasty and crispy.

Example 4 This example used: 1. An unheated potato as a control.

2. A potato heated at 200"F for one hour to an internal temperature of 1200F in a toaster oven.

3. A potato heated for two hours at 200"F to an internal temperature of 150"F in a toaster oven.

Approximately two hours after the heated potatoes were taken out of the toaster oven and air (70'F) cooled in a room, they and the control were peeled and cut in half. One potato half of each potato was cut into thin slices and the other half was cut into the shape of shoestrings.

The slices were allowed to air dry while the shoestring shapes were packaged in aluminum foil and frozen.

It was observed that the control and the potato heated to 120"F internally looked much the same and both began to discolor at the same rate. A potato internal temperature of 1200F is insufficient to inhibit discoloration.

The potato heated to an internal temperature of 150"F showed no sign of discoloration. An internal temperature of 150"F destroys the color forming factor.

The freezing accelerated the changes. By freezing the shoestring shaped potatoes followed by thawing, the control rapidly became black in color and on thawing there was much free liquid evidencing very poor hydration qualities. In contrast, the potato heated to an internal temperature of 150"F remained white and showed no sign of wetness after freezing and thawing. This is a remarkable difference.

The frozen and thawed shoestring-shaped partially baked potato (150"F) was then deep fat fried. It developed a good fried color and looked excellent. In contrast, the control samples were black initially so it was not possible to determine what effect frying had on the color other than it stayed black, and the finished product was not nearly as crispy.

The portions of the potatoes that had been sliced were allowed to air dry for two days. The unheated potato control slices were black and had very little skin. The heat treated (150"F) or partially baked potato slices were translucent and their color was white. Some of these heat treated slices were placed in the toaster oven and the temperature set at 5000F. The slices expanded or puffed-up. In contrast, the unheated potato slices showed little sign of expansion.

The heat treated slices were crispy. This process provides a fat-free low density potato chip.

Example 5 Two potatoes were placed in the toaster oven with the thermostat at 200"F for one and onehalf hours at which time the internal temperature of the potatoes was 128 and 133"F. After cooling in room temperature (70"F) air the potatoes on slicing showed very little evidence of being cooked. On cutting the potatoes into shoestring strips the strips tended to become wet, not as much as an unheated potato control, but not as dry as potatoes brought to an internal temperature of 140 to 1500F. There was discoloration. An internal temperature of 133"F is insufficient to completely destroy the color forming factor in the potatoes.

Example 6 Two potatoes, a russet and a new potato (red) were placed in a toaster oven with a setting of 225"F for four hours. The potatoes reached in internal temperature of 200"F. After standing at room temperature (70"F) for several hours the potatoes were peeled. The outer coat of the potatoes was removed from the body of the potatoes. The peeling became difficult when the internal temperature was 200"F. The whole potatoes had lost firmness and structure. It was difficult to cut the potatoes into slices, cubes, french fries or into the form of grated potatoes.

Example 7 A new potato (red) was placed in a toaster oven at a setting of 200"F for one hour. The potato reached an internal temperature of 175"F. The potato was cut lengthwise into the shape of french fries. Some of the slices were fragile. The heat treated french fries and the control sample (unheated) were allowed to stand at room temperature for two hours. The heat treated sample remained white while the control sample became brown to dark, and wet. The following morning the heat treated sample showed no color change while the control was almost black. A portion of both samples was placed in the freezer overnight and then thawed. No change on freezing and thawing of the heat treated potato was observed. In contrast, the control sample slices were wet, sopping wet and soft.

Example 8 Four russet potatoes weighing 6 to 7 ounces each were placed in a toaster oven set at the lowest temperature of 200"F for one hour. The internal temperature of the four potatoes ranged from 140 to 1600F. The four heat treated potatoes were peeled one and one-half hours after being removed from the toaster and cooled in room temperature (70"F) air. At the same time four untreated potatoes (control) were peeled.

One potato was cut crosswise into thin slices, a second potato was cut lengthwise into the size of rench fries while a third potato was grated. This was one for both the heat treated and the control potatoes.

Observations were made on samples left exposed at room temperature (70"F) for 30 minutes as shown in Table Table I Samples at Room Temperature SHAPE CONTROL HEAT TREATED Slices Color reddish Slices were white.

brown; slices They were dry but were wet. slightly sticky.

French Fries Discolored within Slices were white 15 minutes; fries and dry.

were wet.

Grated Free water. No free water.

Color became reddish Color was white.

brown in a few Slices were slightly minutes. sticky.

Other samples were placed in a freezer overnight and were then thawed and observations made as shown in Table II: Table II Samples Frozen and Thawed SHAPE CONTROL HEAT TREATED Slices Soaked. Much free Moist slices; no water. Badly dis- free water; color colored. white. Fried to hash browns with excellent quality.

French Fries Soaked and wet Moist; no free with much free water; nonsticky; water; badly dis- good color. Put colored. in hot oil and made typical french fries.

Grated Mushy black mass; Moist but still lots of free water. retained shape; no free water.

Fried into excellent hash brown potatoes.

Freezing accelerated the changes that take place in a potato that is cut into various shapes.

The potato discolors even more rapidly and the water retention problems are increased. Much free water is released from the potato structure. The results given in Table II well demonstrate the problems of the potato processors who wish to deliver a good quality product to individual franchises, restaurants and to supermarkets. For this reason, the processors turned to the use of sulfites to prevent discoloration and to the use of gums and phosphates to prevent free water formation. Also, it explains why the processors began to deep fat fry potatoes, sold in the supermarket, since that prevented color formation and the deep fat frying reduced the moisture content of the potatoes yielding products which when frozen could be delivered to the various outlets.

The partially cooked potato of my invention can have manifold applications. An enormous volume of potatoes are used in the production of french fries. McDonald's is a leader in producing golden crisp french fries. Russet potatoes are favored. For this purpose the raw potato is peeled, cut, blanched, partially dried, partially deep fat fried, and then frozen and shipped to its thousands of franchise outlets. Each outlet has deep fat fryer cookers which are used to complete the cooking process. The french fries undergo a partial cooking initially at the potato processing plant and a final cooking at the McDonald's restaurant or other franchise outlets.

By utilizing this invention there will be no need to go to the cost, expense and trouble of blanching followed by double cooking the potatoes in oil. The french fry slices of this invention do not discolor and do not weep so they could be packaged and frozen and sent directly to the franchise outlets where the french fries could be cooked in their fryers. One possible disadvantage in this procedure is that the cooking time would be longer.

In the prior art the french fry strips are blanched followed by partial drying and then given a partial cook in oil, followed by freezing. The final deep fat frying occurs at the franchise outlet.

According to the invention, the color forming factor is eliminated by the initial heat treatment.

There is a slight loss of moisture during the heat treatment but not nearly to the extent obtained by the prior art initial cooking-in-oil step at the potato processing plant. By adding one additional step to the invention, precooking in oil at the processing plants can be eliminated. This step involves a partial drying of the heat treated french fry strips prior to packaging, followed by refrigeration or usually freezing. This partial drying step reduces the moisture content which then reduces cooking time in the fryer and also reduces the slight stickiness which occurs at times in the heat treated potatoes.

Heat treated potatoes cut in the shape of french fries were dried for one and two hours in an oven at a temperature of 175"F and the weight loss was 20 and 30% respectively. At a temperature of 250"F the weight loss in one hour was 25%.

Heat treated slices lost 30 and 40% of their weight when heated for one and two hours in an oven at 175"F.

The slices, the strips of french fries and the grated potatoes of Example 8 were placed in a kitchen oven at a setting of 175"F for four hours. The temperature in the oven was 150"F. The treatment resulted in considerable drying. Samples of the heat treated potatoes and the controls were observed, with the results given in Table Ill.

Table III Samples Partially Dried SHAPE CONTROL HEAT TREATED Slices Slices nonsticky Slices nonsticky; and dark. color white.

French Fries Dry, color off. Nonsticky; dry, white; the pieces still bend.

Grated Moist; stringy; White and retain very dark color. form.

The partially dried product could be packaged, refrigerated and shipped to the ultimate user.

Actually with the need for longer shelf life the products normally are frozen.

A portion of the partially predried potatoes was placed in a freezer overnight. The samples were then allowed to thaw with the results shown in Table IV: Table IV Samples Partly Dried, Frozen and Thawed SHAPE CONTROL HEAT TREATED Slices Discolored, brown Color white; to black; no slices dry to free water, the th&commat; feel; fried to excellent hash brown potatoes.

French Fries Discolored to Color white; the gray-dark color; fries were dry to no free water, the touch; made french fries in hot oil which were good The data shows that heat treatment of potatoes followed by peeling and converting the potatoes into shapes and forms such as slices, grated potatoes, french fries, etc. followed by partial drying prior to packaging, and then freezing, could well eliminate all deep fat frying in the potato processors' plants. The deep fat frying would be then done only once, that is, just prior to the consumption of the french fries.

There is of course no need to stop the drying process at an intermediate stage. Drying may be carried to substantial completion, i.e. a water content of about 8 to 15% by weight. The heat treatment stabilizes the potato thus providing the potato processor much flexibility. Since the invention eliminates color formation and enhances hydration one can completely dry the potatoes with minimal difficulty. The dried slices, chunks, french fries or grated potatoes can be re-hydrated rapidly and then used in any desired way in cooking.

Dried potatoes are now on the market including mashed potatoes, scalloped potatoes, creamy Italian potatoes, au gratin potatoes and many other forms. Almost all of these products are made using sodium bi-sulfite as an additive. Also, most of them use phosphates and other additives. The label declarations of four major dried potato products now in the supermarkets read as follows: 1. Betty Crocker Potato Buds, Mashed Potatoes No Artificial Flavors Made from 100% Russet Potatoes Ingredients: dried potatoes (with freshness preserved by sodium bisulfite and BHT). Mono and diglyceride (to improve texture) 2. Pillsbury Hungry jack Mashed Potatoes Artificially Flavored Ingredients: Potato flakes, monoglycerides, natural and artificial flavor, sodium bisulfite (to maintain color), calcium stearoyl lactylate, BHA and BHT (to protect flavor), sodium acid pyrophosphate, citric acid.

The Pillsbury Company, Minneapolis, MN 55402-1464 3. Instant Mashed Potatoes Ingredients: potato flakes, mono and diglycerides, sodium acid pyrophosphate, sodium sulfites, citric acid and BHA as preservatives.

Jewel Companies, Inc., Melrose Park, IL 60160 Jewel Companies, Inc., 1977 4. Betty Crocker Scalloped Potatoes Made from 100% Idaho Russet Potatoes Ingredients: dried potatoes, enriched flour (wheat flour, niacin (A B vitamin), iron, thiamin mononitrate (vitamin B1), riboflavin (vitamin (B2), salt, corn starch, partially hydrogenated soybean oil, dried corn syrup, whey, dried cheddar cheese (milk, salt, cheese culture, enzymes, calcium chloride), natural and artificial flavor, malto dextrin (a flavor carrier), buttermilk, monosodium glutamate (to enhance fiavor), dried celery, spice, sodium caseinate (a milk protein), wheat starch, dipotassium phosphate, dried blue cheese (milk, salt, cheese culture, enzymes), disodium phosphate, artificial color, yellow corn flour, defatted soy flour, hydrolyzed vegetable protein (a natural flavor), disodium inosinate and disodium guanylate (to enhance flavor).

Color and freshness preserved by sodium bisulfite, sodium sulfite and BHA.

Distributed by General Mills, Inc.

General Offices, Minneapolis, MN 55440 Made in U.S.A.

Net Wt 148 grams The complexity of these label declarations from some of the major potato processors in the United States is in striking contrast with the simplicity of the procedure given in a Betty Crocker's Cookbook for making "fluffy mashed potatoes", which states: "Cook potatoes until tender, not mushy. Drain.

Shake potatoes in a kettle over heat until dry.

Mash thoroughly. Season with salt and pepper. Add butter and heated milk (a half a cup to eight potatoes). Whip into potatoes, beating until fluffy." Nowhere in this recipe are sulfites, diglycerides or phosphates mentioned. All these ingredients are used since the processors did not appreciate or conceive of the invention where the potato is stabilized thus making use of these additives unnecessary.

By heat treating potatoes, preferably at 150 to 165"F, a stable vegetable product is obtained.

The potatoes, desirably after peeling, can then be cut to a desired shape and thickness. They can be grated, cubed or diced, cut lengthwise into 3/8 inch strips for french fries or into any desired shape. The product can then be dried. On drying the color remains white and the surface becomes glassy-like and vitreous.

The dried products can be rehydrated readily by the addition of water and then utilized in any desired fashion to produce mashed potatoes, cottage fries, lyonnaise, au gratin, french fries, potato pancakes, etc.

Example 9 Five russet potatoes weighing from 3 to 4 ounces each were placed in a toaster oven at a 200"F setting for 45 minutes. The internal temperature of the potatoes when taken out of the oven ranged from 145-160"F. The potatoes were firm. The potatoes were cooled in air (70"F) and peeled three hours after being taken out of the oven. They were shaped into thin slices, french fries, potato balls, quarter-inch diced and grated.

The potato products were placed in a cookie sheet which was then placed in the oven where the setting of the oven was 175"F. The potatoes were kept in the oven for 6 hours and then allowed to sit at room temperature (70"F) for another 8 hours.

The grated sample was completely dry and had a glassy surface and appeared to be toasted slightly.

The thin slices were dry with a glassy-like translucent surface and their color was light.

The french fries had shrunk on drying to maybe 1/3 their original size and they had a very light toasted color.

The diced potatoes and potato balls were dry on the outside but still had moisture in the center of the chunks.

The dried, grated potatoes were covered with water for about one hour, the excess water was drained off and the hydrated product was then fried to make excellent hash browns. The ingredient declaratior would simply read: potatoes. The dried grated potatoes could be packaged in 50 pound bags and shipped to any desti- 24 nation in a very simple way for use in making hash brown potatoes, potato pancakes, cottage fries, etc..

The dried french fries were hydrated in hot water for one hour. The hydrated product was then deep fat fried to produce french fries. This shows there would be no need, when this process is used, to ship the product in a frozen or refrigerated state. The dried potatoes could be shipped, rehydrated by the purchaser at any time and then cooked.

The dried potato slices when hydrated could be cooked into au gratin potatoes, scalloped potatoes or any type of a potato dish where hydrated slices are used. The hydrated slices when added to hot oil expand to give a crisp product much like a potato chip. The hydrated slices also expand in hot air and give a fatfree crispy potato product of a low caloric content. The color of the products remains excellent.

The dried diced potato was simmered in boiling water for 30 minutes. It expanded and became hydrated. The product was white and looked identical to fresh cut potatoes. The hydrated potato was mashed and a little milk and butter was added to give excellent quality mashed potatoes. All these dehydrated products could be converted into any desired potato product and in all cases the label declaration would read: potatoes. No additive is required.

Example 10 Baking potatoes (Wisconsin), weighing 14 to 15 ounces each, were placed in a toaster oven at a 200"F setting for different time intervals to better determine the temperature at which the destruction of the color forming factor appeared to occur. The results are given in Table V.

Table Q Heating Potatoes For Different Time Intervals Observation of the Sliced French Internal Fries after Test Minutes Temperature Freezing and Number in Oven Degrees F. Thawing: Control 0 Badly discolored; very wet, 1 20 125-128 Badly discolored; much free water, very wet.

2 25 136-137 Most of the strips were white, a few discolored; quite wet.

3 30 140-141 Excellent color; slices show partial gelatiniza tion, some free water.

4 45 150-158 Color is excellent; the strips show gelatinization within the potato; very little free water.

Each of the potatoes was cut lengthwise into french fries which were then placed in the freezer overnight and then thawed before the observations were made.

Some of the french fries from Tests 3 and 4 were deep fat fried with very good quality.

Potatoes prepared as shown in Table V were allowed to stand overnight, peeled, and were then grated. The grated product was frozen and then thawed and observed with the results shown in Table VI.

Table VI Appearance of the Test Internal Temperature Frozen/Thawed Number Degrees F. Grated Potatoes 1 125-128 Color brown; soaking wet.

2 136-137 Tan color; off white; can squeeze out much free water.

3 140-141 Color white; there is some free water.

4 150-158 The color is good; partially gelatinized; holds water the best.

The temperature for complete destruction of the color forming factor must be at least 140"F or higher. At an internal temperature of 136-137"F, approximately 90% of the color forming factor is destroyed. When the potato internal temperature reaches 140"F there is about 100% destruction. The grated potatoes with the internal temperature of 150-158"F has the best water binding properties.

Example 1? Potatoes can be heated in boiling water but it is preferred to heat the potatoes in air. By immersing baking potatoes weighing 11-13 ounces in boiling water, an internal temperature of 140"F. was reached in 25 minutes. This product can be sliced but on observation it was seen that the outer surface of the potatoes was overhydrated and was somewhat sticky, which is undesirable. It is best to heat the potatoes in a nonliquid medium, desirably air.

Example 12 Russet potatoes weighing 6 to 9 ounces each were placed in an oven at a 400"F setting for different time intervals to determine the time and the temperature at which potatoes lose their firmness and integrity and become crumbly and baked. Potatoes are normally baked for one hour at 400"F. After being heated in the oven the potatoes were allowed to cool and were examined three hours later.

The results of this study are given in Table VII.

Table VII Partial Baking at Various Temperatures and Times Time in Oven Internal Test at 400 F Temp. of Cutting No. Minutes Potato F Peelability Quality 1 10 140 Peels very Slices, dices good and grates with no problem 2 20 170 " " 3 30 181 " " 4 45 208 On peeling Potato the potato crumbles and crumbles and breaks up on breaks up grating and cutting 5 60 212 Outside peel comes off in sheets; potato " soft and breaks up * Thermometer placed lengthwise in the center of the potato.

** The same results were noted with potatoes allowed to cool overnight before being examined.

Exposure for 30 minutes in the oven at 400"F raises the internal temperature to 181"F. This potato on cooling was still firm and had a continuous smooth texture and it could be cut into any desired shape. In contrast, by continuing the heating up to 45 minutes the potato underwent a remarkable change from the longer baking. The potato became crumbly and had little structural integrity. On exerting pressure to it the potato broke up and could not be cut into a desired shape or form.

To practice the invention a partially baked potato should be used that has firmness and integrity. Also, the color forming factor must be destroyed. Heating small size potatoes from 10 minutes to 30 minutes in an oven at 400"F falls within this requirement. Heating might continue for another 5 minutes but with a 45 minute heating interval the potato is substantially unsuitable.

Small size potatoes heated for as little as 10 minutes at 400"F are suitable. Larger size potatoes require longer heating times to destroy the color forming factor.

Example 13 Idaho potatoes were heated in an oven at 4000F for different time intervals. The cooled potatoes were cut in half lengthwise and the surface was observed for the extent of cook or gel formation. This was then related to surface color after the potatoes were frozen overnight followed by exposure to room condition for 2 hours.The following results were obtained: Table VIII Appearance of Cut Surface Color of Time in Oven Internal Temp.* %Opaque or Cut Test &num; Minutes of Potato F Uncooked Surface 1 0-Control --- 100 Over all red color 2 10 125-128 75 Inside off color black 3 15 130-136 45 Inside off color black 4 16 136-142 20 Almost black in the center; inisde portion opaque 5 17.5 155-160 0 Good color Uniform gel 6 20 155-160 0 Good color Uniform gel ** Two immersion thermometers were used with one penetrating from each end of the potato.

In Test 3 above, exposure of the potato for 15 minutes at 400"F results in an internal temperature of 130-136"F with the outer half of the potato in the gel state while the center portion looks uncooked and on exposure darkening occurs. By exposure for 16 minutes the internal temperature is increased to 136-142"F and now only about 20% of the inner surface of the potato is white or uncooked and darkening occurs on air exposure. Exposure for an additional 1.5 minutes results in a complete cook of the potato and 100% of the color forming factor is destroyed.

Example 14 An experiment was designed to show the effect of the heat treatment of unpeeled potatoes on both color stability and water retention. Russet potatoes weighing 9-10 oz. each were heated in an oven at 425"F for 15 and 20 minutes and compared to unheated potatoes. The control and treated unpeeled potatoes were cut in half lengthwise and the surface was observed to determine heat penetration. The potatoes were then placed in an unsealed zip-lock plastic bag and placed in a freezer overnight and then allowed to thaw and remain at room temperature for 17 hours. Observations are given in Table IX.

Table IX Storage At Room Temperature For 17 Hours Volume (ml) of Free Length of Appearance of Liquid That Heating Internal Cut Surface Color Seeps out at 425 F Temp. of % Opaque of Cut of One Test &num; mins. Potato F or Uncoooked Surface Potato 1 0 --- 100 Almost 30 black black liquid 2 15 134 75 Very dark 15 brown in brown colored the uncook liquid ed portion 3 20 154 0 White 0 Uncolored No free liquid The partially baked potato must have a uniform gel like structure with no center ring of opaque or uncooked appearance. The internal temperature of the potato must be sufficiently high to attain this uniform gel-like state, especially in the center of the potato where heat penetration takes the longest time.The gel-like state imparts color stability and also enhances water retention which is very important in relation to the storage life of processed potatoes.

Example 15 The predominant frozen potato product is french fries, other frozen potato products are byproducts of the french fry production line. U.S. patent 3,397,993 describes french fry manufacture which involves peeling, trimming, cutting into elongated segments, blanching as with steam to translucency, dehydrated internally to about a weight loss of about 35%, fried for a short time and then frozen prior to finish frying.

By far, the greatest tonnage of frozen processed potatoes is made up by french fries. The usage of the structured stabilized process of this invention should simplify the manufacture of french fries and can also result in quality improvement.

Three Idaho potatoes were placed in an oven at 425"F for 25 minutes to an internal temperature of 160164"F. The cooled potato peeled easily and was cut lengthwise into 1/4" strips. The strips were placed on a tray and dried in an oven at 2500F for 30 minutes and the weight loss was 37%. The partially dried strips were packaged and put in the freezer overnight. The product looked excellent with no sticking of one strip to the next. The product was taken out of the freezer and allowed to thaw and was then deep fat fried in oil at 400"F to a golden brown color much like McDonald's french fries which took 30-40 seconds in the frier.

The finished french fries had a golden color, a good bite and a little more texture than McDonald's french fries.

By utilizing this invention one can eliminate the blanching step and also the deep-fat processing step at the point of manufacture. Also, the by-product of the french fry manufacture will have better structure and can yield higher quality frozen hash-browns or other products.

Example 16 Idaho potatoes weighing 12-16 oz. each were placed in an oven at 425"F for 25 minutes to an internal temperature of 150"F. The cooled peeled potato was grated and after being stored in the refrigerator for 9 days was made into a thick patty and put in the freezer overnight. This patty was compared to Frozen Bel-Air shredded Hash Browns which are distributed by a major food supermarket chain with an ingredient declaration: Potatoes and dextrose. The cooking directions in the package were followed. The frozen patty of this invention on frying had a golden-brown color. The patty stays together with good flavor a crispy mouth feel. In contrast the Bel Air product tasted dry, the color is white, the patty breaks up and the texture is mushy.

There is no comparison in quality.

Example 17 A potato was partially baked, cooled, peeled and sliced. By partially drying slices cut to the desired thickness for potato chips to a weight loss of 40% there could be advantages in potato chip manufacture. It would be unnecessary utilizing this invention to remove the starch and other substances released from fresh unheated potato slices. Heating the pieces to an internaltemper- ature of 1450F or higher converts the potato to a gel-like state and slicing cuts cleanly and the individual slices do not stick.

Normally the oil used for deep fat frying evaporates 4 pounds of water for each pound of potato chips produced. By utilizing partially dried potato slices with a weight loss of 40% the oil would then have to evaporate only 2 pounds of water per pound of chips. Other advantages would relate to the oil content of the chips and to the flavor.

Potato chips were made from dried potato slices by heating potatoes for 20 minutes at 400"F to an internal temperature ranging from 158-170"F. On cooling, the potatoes were peeled and cut cross-wise approximately 1/8" thick. The slices were dried for 50 minutes at 225"F. On cooling, the slices were hard, glassy and vitreous and were stored at room temperature. for 3 weeks in a zip-lock bag. Slices immersed in hot oil at 250 and 300"F showed no expansion. At 350"F expansion occurred and within 1 minute there was a 4-fold increase in volume and the product had crunch. The color was light, and the slice was a little thicker than desired for potato chips. This could be a desirable snack. At 400"F expansion occurred in seconds.The product was crispy and tasty.

Example 18 Whole unpeeled potatoes were heated for 25 minutes at 400"F to an internal temperature of 152"F and cooled. The peeled potatoes were diced to 1/4" chunks and after 13 days of storage under refrigeration the samples were perfect but on longer storage to 16 days the potatoes had lost that bright fresh color.

The refrigerated pre-cut potatoes of the invention have structure and in one test diced (1/4") potatoes stored for 9 days were fried and the hash browns were crisp with good color. In another case diced potatoes stored for 16 days were made into hash browns. The hash browns looked like fresh cut potatoes. The smell and flavor was like fresh potatoes and the potatoes had browned very well.

By utilizing this invention there could be a very sound, economic basis to offer to the supermarket and to the various franchises and restaurant chains, a variety of refrigerated fresh pre-cut potatoes, grated or diced in whichever shape is to be used for hash browns or other purposes where the fresh cut potato is partially dried prior to packaging. A suggested weight loss could be 35-50%. The refrigerated product would fry much faster. The freight cost would be halved. The storage space reduced. If desired, these products could be frozen and sold in supermarkets or other outlets.

Example 19 Dehydrated potatoes include mashed potato flakes, potato flour, sliced, diced, au gratin, scalloped, potato granules and shredded hash browns.

Potato flakes are normally produced by washing the potato, sorting, peeling, washing, trimming, and then slicing. The sliced potatoes are pre-cooked at about 165"F, followed by cooling, and then moved to a final cook followed by mashing, and usually drum drying. Additives are usually added prior to drying. The slices from the drier are then reduced in size for the particular usage. By utilizing this invention the washed potato will be baked to an internal temperature of 160-190"F, followed by cooling, peeling, mashing to the desired solids, additional cooking, followed by drum drying or drying by other means. The process will be greatly simplified.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

Claims (27)

1. A process which comprises: heating unpeeled whole potatoes until they reach an internal temperature of at least 1450F which destroys the color forming factor but for a time which results in only partial baking or cooking of the potatoes such that they maintain their structural integrity with enhanced water binding properties.

2. A process according to claim 1 in which the internal temperature is in a range of about 145 to 195"F.

3. A process according to claim 1 in which the internal temperature is in a range of about 150 to 175 F.

4. A process according to claim 1 in which the potatoes are heated in air.

5. A process according to claim 1 in which, after heating, the potatoes are cooled.

6. A process according to claim 5 in which the cooling is in air.

7. A process according to claim 1 in which after heating the potatoes are cooled and peeled.

8. A process according to claim 7 in which the peeled potatoes are cut into pieces of a desired shape and size.

9. A process according to claim 8 in which the potato pieces are refrigerated or frozen.

10. A process which comprises: heating whole unpeeled potatoes until they reach an internal temperature of 145 to 195"F which destroys the color forming factor but for a time which results in only partial baking or cooking but at least partial gelatinization of the potatoes such that they maintain their structural integrity with enhanced water binding properties; cooling the potatoes; cutting the cooled potatoes into pieces; and partially drying the potato pieces.

11. A process according to claim 10 in which the partial drying reduces the weight of the potato pieces about 20 to 40%.

12. A process according to claim 10 in which the dried potato pieces are packaged and then refrigerated or frozen.

13. A process according to claim 11 in which the partially dried pieces in the form of slices are cooked in hot oil to produce potato chips.

14. A process according to claim 10 in which no additive is added in the process to prevent color formation or enhance water retention of the partially dried potato pieces.

15. A process according to claim 12 in which the potato pieces are frozen in the form of french fries and then cooked in hot oil to produce french fries.

16. A process which comprises: heating whole unpeeled potatoes until they reach an internal temperature of 145 to 195"F which destroys the color forming factor but for a time which results in only partial baking or cooking but at least partial gelatinization of the potatoes such that they maintain their structural integrity with enhanced water binding properties; cutting the potatoes into pieces or mashing the potatoes; and drying the potato product.

17. A process according to claim 16 in which the potatoes are dried to a moisture content of about 8 to 15% by weight.

18. A process according to claim 16 in which the dried pieces are heated in the absence of fat to produce a low calorie content puffed potato product.

19. A process according to claim 16 in which the dried pieces are heated in oil to produce a light color puffed potato product.

20. A process according to claim 16 in which the dried pieces are rehydrated in water to yield pieces having the color and consistency of cut fresh potatoes.

21. A process according to claim 16 in which the dried potato pieces are simmered in boiling water to complete cooking followed by conversion into mashed potatoes.

22. A process which comprises: heating whole unpeeled potatoes until they reach an internal temperature of about 150 to 175"F which destroys the color forming factor but for a time which results in only partial baking or cooking but at least partial gelatinization of the potatoes such that they maintain their structural integrity with enhanced water binding properties and can be subsequently peeled while maintaining their shape; cooling the heated potatoes; and peeling and then cutting the peeled potatoes into pieces.

23. A process of treating potatoes which makes use of an additive unnecessary to protect the potato color which comprises: heating whole unpeeled potatoes until they reach an internal temperature of 145 to 195"F which destroys the color forming factor but for a time which results in only partial baking or cooking but at least partial gelatinization of the potatoes such that they maintain their structural integrity with enhanced water binding properties; cooling the potatoes and then peeling the potatoes in the absence of an additive otherwise used to protect the potato color; cutting the cooled peeled potatoes into pieces of desired shape and size and storing the potato pieces in refrigerated or frozen condition; and subsequently cooking the pieces for immediate consumption.

24. A process of treating potatoes which makes use of an additive unnecessary to protect the potato color, which comprises: heating whole unpeeled potatoes until they reach an internal temperature of 145 to 195"F which destroys the color forming factor but for a time which results in only partial baking or cooking but at least partial gelatinization of the potatoes such that they maintain their structural integrity with enhanced water binding properties; cooling the potatoes and then peeling the potatoes in the absence of an additive otherwise used to protect the potato color; cutting the cooled peeled potatoes into pieces of desired shape and size; and subsequently cooking the potato pieces to produce a product suitable for human consumption hot or after cooling.

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25. A process in accordance with Claim 1, substantially as described in any one of the foregoing Examples.

26. Potatoes whenever treated by the process of any one of the preceding claims.

27. Any novel feature or combination of features described herein.