RU2118092C1 - Method of potato freezing by natural cold - Google Patents

Abstract

FIELD: freezing of vegetables and fruits in the regions with steady minus winter temperatures. SUBSTANCE: method involves exposing whole, non-blanched potato tubers to natural cold and freezing tubers through to cambial layer; heating this layer to 30-60 C; repeatedly exposing to natural cold. Method allows usage of expensive freezing equipment to be avoided. EFFECT: increased efficiency by reduced number of tuber processing operations and reduced storage losses.

Description

 The invention relates to the freezing of vegetables and fruits. The method is suitable for areas with stable winter freezing temperatures.

 Known methods of freezing potatoes to obtain semi-finished products using various plants that produce cold, with preliminary washing, peeling, cutting, blanching according to TU III-4-35-85. The methods require high energy costs to obtain cold and processing of tubers.

 A known method of freezing potatoes with natural cold at home (Abramov A.F. Cooking quick-frozen products from potatoes, root crops, vegetables at home using natural cold. - Yakutsk, 1993 - prototype).

 This method involves washing, peeling, cutting, blanching and freezing with natural cold, followed by storage in the cold in a package or sealed container.

 In both cases, chopped tubers are frozen, which complicates their storage and transportation.

To achieve a technical result ensuring freezing without the use of expensive freezing equipment, to reduce technological operations during the processing of tubers, to shorten the shelf life of tubers after harvesting in insulated rooms (storages) and, accordingly, to reduce losses associated with storage, create the possibility for transportation of tubers in the cold season years of ordinary freight transport and storage at natural winter temperatures, it is proposed to freeze, unlike Whole tubers type without blanching, freezing and initially conducted to a depth of cambial layer of tubers. The freezing time of the layer depends on the temperature of the outside air, the size of the tubers, their laying and is determined empirically. Best results at -20 ^o C and below. The tuber core does not freeze. Then, this layer of tubers is heated to 30-60 ^° C and the tuber is re-frozen to the full depth.

For example, tubers with a diameter of 40-60 mm prepared by conventional methods for freezing and conditioned at room temperature were placed on trellised trays with a layer of two to three tubers and at a temperature of -25. . .-30 ^o C were in the external cold for 15 - 20 min and frozen to a depth of 3 - 5 mm, which approximately covered the cambial layer of the tuber, after which the freezing stopped and some of the tubers were treated with warm water 30 - 40 ^o C for 5 - 6 minutes , the other part was treated with warm air 50-60 ^o C for 10-15 minutes, after which the tubers were taken out for re-freezing for several hours.

 Tubers frozen in these ways were consumed both immediately after thawing and ordinary cooking, and without preliminary thawing, i.e., frozen ones were dipped in hot water and cooked until cooked. Differences in taste were not observed. Biochemical analysis showed no noticeable deviations in the composition of the tubers before and after freezing.

Claims (1)

 \ \\ 1 The method of freezing potatoes involves exposure to natural cold, characterized in that natural cold is applied to whole potato tubers in two steps to ensure freezing, the first freezing is performed to the depth of the cambial layer of the tuber, then this layer is heated to 30 - 60 <198> C and re-freeze tubers to the full depth.