Patent GB-1024884-A (GB)
Title: Process for preparing a dehydrated potato product
IPC: A23L19/15
Filed: 1963-07-05
Abstract: 1,024,884. Dehydrated cooked potato. GENERAL FOODS CORPORATION. July 5, 1963 [July 5, 1962; Dec. 24, 1962], No. 26710/63. Heading A2D. A dehydrated potato product is prepared be removing adhered foreign matter from raw potatoes to leave skin, eyes and defects as undesirable portions on the potatoes, precooking the potatoes at 140‹F to 195‹F for about 5 to 60 minutes in an aqueous medium, quenching the precooked potatoes until their temperature is less than 100‹F, cooking the quenched potatoes until they are soft enough to mash, mashing the cooked potatoes, slurrying the mashed potatoes with sufficient aqueous medium to form a slurry containing about 7 to 16% potato solids and including the abovementioned undesirable potato portions, mechanically separating the undesirable potato portions from the potato slurry and dehydrating the slurry to a stable moisture content. In an optional procedure the slurry is dewatered to a filter cake, the dewatered potatoes are reslurried to form a slurry containing about 7 to 16 per cent potato solids and the reslurried potatoes are spraydried; a process for preparing dehydrated potato products involving this procedure, is claimed in Specification 1,024,885. Raw potatoes from which adhered foreign matter has been removed, are sliced, dipped in bisulphite solution and then treated with an aqueous solution of sodium acid pyrophosphate, which prevents after-cooking darkness; the pyrophosphate may also be included in the aqueous medium used for pre-cooking or quenching the potatoes. The treated sliced raw potatoes are precooked, and then quenched to a temperature below 70‹F by spraying with or immersion in cold water or brine, or treatment with refrigerated air or shaved ice. After draining, the potatoes are cooked by conventional methods (specified) until they are soft enough to mash and are mashed while hot between crushing rolls having a setting of about 0.018-0.060 inch, or between belts. The mashed potatoes are slurried with a required amount of water containing antioxidant, bisulphite, and 0.01-3.0% by weight of the potatoes of calcium chloride for hardening the walls of the potato cells; the calcium chloride may also be incorporated into the precooking medium or the quenching medium. The undesirable potato portions are separated by passing the slurry containing them through screens of U.S. Nos. 4 to 20 mesh size. Preferably a vibrating screen of No. 5 or No. 8 mesh size is employed. Any remaining specks of peel, eyes and rot are removed by passing the screened slurry through a fine vibrating screen of e.g. No. 40 mesh size. The slurry is now dewatered on a horizontal vacuum filter, until the solids content of the dewatered potatoes is 14-22% and is preferably substantially equal to the solids content of the raw potatoes being processed. The clean potato cells are then reslurried and dried as by spraying in air having an inlet temperature of 250‹-550‹F and an outlet temperature of 200‹-260‹F or by other conventional means (specified) to give a final potato product having 5¢-6% moisture content. The dimensions and operational characteristics of a suitable spray-drying apparatus are given. Emulsifiers, aerating or fluffing agents, antioxidants and bleaching agents may be added to the filter cake during the reslurrying. Emulsifiers: 0.10-2.50% by weight of the potato solids of monoglycerides (incorporating minor proportions of the di- and triglycerides), propylene glycol monoesters and diethylene glycol mono-esters (a number of compounds are mentioned); Aerating or fluffing agents: 0.25-3.0% by weight of the potato solids of methyl cellulose; Antioxidants: 25-50 p.p.m. of butylated hydroxytoluene, propylene glycol and citric acid in a solution of propylene glycol; Bleaching agents: 25-50 p.p.m. of sodium sulphite and metabisulphite. The process is described in considerable detail. In the embodiments, the potato slurry or reslurry is spray-dried or drum dried.