RU2499210C1 - Method for sublimation drying of farm animals blood - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: stabilised blood is poured into a tray wherein liquid nitrogen is then poured. Liquid nitrogen starts boiling under atmospheric pressure; the boiling temperature is equal to 103±2°C. The boiling (freezing) process lasts no more than 5 minutes. Then the frozen object is placed into a sublimation drying chamber where the drying process is performed under a pressure of 100-500 Pa. The temperature in the chamber is maintained at a level of 20÷40°C. The drying process duration is equal to 10÷200 minutes.

EFFECT: liquid nitrogen usage reduces the duration of the process of dehydrated blood production which decreases the drying process prime cost; protein components of dried blood produced with liquid nitrogen usage are subjected to minor destruction than in other drying versions.

Description

The invention relates to the food industry and for the production of a protein mixture from the blood of slaughtered animals.

One of the important areas of blood processing is to obtain nutrient media for the cultivation of microorganisms based on the blood proteins of farm animals. The attractiveness of blood as a raw material for obtaining a high-quality nutrient medium lies in the presence of various protein fractions, which it is desirable to maintain in a state as close as possible to the "native" one. This can be achieved using freeze-drying using liquid nitrogen as an agent for preliminary freezing.

As you know, freeze-drying is caused by the preliminary freezing process, which is carried out either directly in the drying chamber at a pressure decrease of less than 610.8 Pa (pressure of the triple point of water), or previously in freezers at atmospheric pressure. The use of liquid nitrogen reduces the time of preliminary freezing of blood.

The known method of freeze-drying food products according to patent No. 2283603, IPC A23L 3/44, claimed on 02.21.2005, published on 09.20.2006, Bull. No. 26. The method allows you to dry the moisture-containing product to a mass fraction of moisture of 30-40%, using a stepwise decrease in pressure, which complicates the drying process, and also increases the overall drying time.

A known method of preserving (freeze-drying) of liquid and pasty products according to patent No. 2413147, IPC F26B 5/06, claimed on July 20, 2009, published on February 27, 2011, Bull. No. 6. This method is the closest prototype to the claimed invention. The method includes pre-freezing in a layer of calcium chloride before the direct drying process by sublimation. At the same time, the freezing process itself is carried out in a freezer at a temperature of minus 18 ° C. This approach simplifies the drying process, but freezing in a freezer in a layer of calcium chloride solution increases the duration of the preliminary freezing process and the drying process itself and, as a result, increases the cost of the process.

The technical task of the claimed invention is to reduce the duration of the preliminary freezing process and reduce the cost of the drying process.

The technical solution consists in using liquid nitrogen as a low-temperature medium for preliminary freezing, as well as in the use of freeze-drying.

The technical result is achieved as follows.

Stabilized blood is poured into a baking sheet, into which liquid nitrogen is then poured. At atmospheric pressure, liquid nitrogen begins to boil, while the boiling point is minus 103 ± 2 ° C. The process of boiling (freezing) lasts no more than 5 minutes. Then the frozen object is placed in a freeze-drying chamber, where the drying process is carried out at a pressure of 10 ÷ 500 Pa. The temperature in the chamber is maintained at a level of 2 ÷ 40 ° C. The duration of the drying process is 100 ÷ 200 minutes.

The claimed invention has the following advantages:

1. The use of liquid nitrogen reduces the duration of the process of obtaining dehydrated blood, which reduces the cost of the drying process.

2 The protein components of the obtained dry blood when using liquid nitrogen are less degraded than with other drying options.

Example.

Stabilized blood of farm animals with a volume of 500 ml is poured into a baking sheet, while the thickness of the layer of poured blood is 20 mm, liquid nitrogen is poured into the same pan to a total boiling mass (liquid nitrogen and blood) of 40 mm. The baking sheet is equipped with a special lid to avoid splashing drops of boiling nitrogen. After the pre-freezing process has ended (the end of the boiling process), the lid is removed from the pan and the pan is placed in a freeze-drying chamber. After installing the experimental sample in the drying chamber, turn on the refrigerating machine and after entering the freezing mode of the desublimator evaporator (-35 ° C), the vacuum pump is turned on. During the experiment, the temperature and pressure in the chamber are recorded. The duration of the drying process in this example was 140 minutes.

Thus, the obtained dry blood contains all its proteins, the physical state of which is close to the “native” one, which allows one to obtain high-quality nutrient media for the cultivation of microorganisms on its basis.

Sources of literature

1. Patent (RF) No. 2283603, IPC A23L 3/44, filed on February 21, 2005, published September 20, 2006 Bull. No. 26. / Method of freeze-drying food / A.S. Gorlatov (analog).

2. Patent (RF) No. 2413147, IPC F26B 5/06, pending July 20, 2009, published February 2, 2011 Bull. No. 6 / Method of canning (freeze-drying) of liquid and pasty products / G.V. Semenov, E.V. Budantsev, M.S. Bulkin, Yu.R. Gataullina (prototype).

Claims (1)

A method of freeze-drying blood of farm animals, comprising using baking sheets with a low-temperature medium, wherein the thickness of the layer of low-temperature medium in the baking sheet is at least twice the thickness of the layer of frozen blood in the container, freezing, freeze-drying, characterized in that liquid nitrogen is used as the low-temperature medium and freeze-drying is carried out at the following parameters: pressure 100-500 Pa, the temperature in the chamber is maintained at 20 ÷ 40 ° C, the duration of the drying process 100 ÷ 200 minutes