RU2136151C1 - Live fish storage method - Google Patents

Abstract

FIELD: fish industry, in particular, storage of live fish, such as tuna. SUBSTANCE: method involves filling hermetically sealed fish storage vessel with sea water; adding gaseous nitrogen used as preservative in the ratio of fish : nitrogen - 5 : 1 into sea water. Usage of gaseous nitrogen as preservative substantially retards oxidation of lipids and development of aerobic microflora. EFFECT: increased efficiency, simplified method and increased live fish storage time. 2 cl, 2 ex

Description

 The invention relates to the fishing industry, and in particular, to methods for preserving live fish in tuna fisheries.

 A known method of preserving living organisms by exposure to carbon dioxide / 1 /. When using carbon dioxide and lowering the storage temperature, the oxygen content in fats decreases, which slows down the oxidation process.

 The main disadvantages of this method include the high cost of carbon dioxide, as well as the need for special equipment.

The closest in technical essence and the achieved result is the "Method for storing fresh fish" / 2 /. According to the method, the fish is stored in a sealed container at a temperature of 4-12 ^o C, adding oxygen as a preservative, in the complete absence of carbon dioxide.

 The main disadvantage of this method is the fact that it is unsuitable for storing live fish.

 The task set by the authors of the proposed method is to provide the possibility of storing live fish, as well as increasing the duration of its storage.

 The task is achieved due to the fact that the tank is pre-filled with sea water, and nitrogen gas is used as a preservative. Moreover, add water to live fish in a ratio of 2: 1 gaseous nitrogen in the ratio of fish: nitrogen 5: 1. The addition of gaseous nitrogen to seawater creates an inert atmosphere, significantly inhibits the development of aerobic microflora and slows down the oxidation of lipids, which contributes to a more “soft” drug addiction in combination with eubiosis.

 Nitrogen released from sea water due to its lower molecular weight saturates the blood and lipids of tuna, while not having an adverse effect on the body.

 Nitrogen prevents the violation of biochemical changes in the body, which helps to stabilize the quality of canned fish in a state of drug addiction.

 The proposed method of conservation is most suitable for fish in tuna fisheries.

This is explained by the fact that in tuna, as in poikilothermic organisms, body temperature is unstable, which is inherent in endothermic objects. Owing to their own metabolic processes, they retain a significant part of the heat using their unique method. This provides them with an increase in body temperature 3-10 ^o C above the environment and allows you to supply the blood with enough oxygen, especially for those muscles that have a lot of work to do. This is facilitated by the high oxygen capacity of tuna blood, which reaches hemoglobin in erythrocytes up to 21.2% per 1 g, while in other fish species it is 8-11% per 1 g.

 In addition, it is tuna that contain from 3 to 10% of blood by weight, which is saturated with nitrogen faster than its adipose tissue.

 The proposed method is as follows.

 In the lower part of the sealed container, filled with sea water and live fish in a ratio of 2: 1, nitrogen gas is supplied to the ratio of fish to nitrogen 5: 1, after which the container is closed.

If the water temperature reaches 20-25 ^o C, then after a few days the container is opened and pure sea water with a temperature of 20-25 ^o C is added until the ratio of water to fish is 2: 1. After 1-3 hours, up to 70% of the fish in the tank comes to life.

 Example 1

Take 10 kg of live tuna without mechanical damage with a body weight of about 2 kg and with a body temperature of about 25 ^o C, placed in an airtight container, pour there about 20 liters of sea water. Then, 2 kg of gaseous nitrogen is added to the container from the container. At the same time, tuna quickly “falls asleep”. After that, the container is closed and stored in ship conditions in the fishing area at a natural temperature (20-25 ^o C) of sea water for 7 days.

After this time, the container is opened, add to it about 20 liters of sea water at a temperature of 20-25 ^o C. After 1 to 3 hours after that, 70-80% of the fish in the tank comes to life.

 Example 2

Take 10 kg of live fish (4 - 5 pieces) without mechanical damage and with a body temperature of 20-25 ^o C and place it in a sealed container. 20 l of seawater cooled to 1 - 2 ^o C are added to the container and 2 kg of gaseous nitrogen are immediately introduced there from a cylinder. Tuna immediately loses its mobility. After that, the container with fish is closed and stored for 14 days at a temperature of the mixture (fish with water) 1-2 ^o C. Then the container is opened, add 20 l of warm sea water (20-25 ^o C). After 3-6 hours, most of the fish (70-80%) comes to life.

 Thus, after the termination of the action of nitrogen on the body, the fish gradually returns to normal activity in pure sea water. In addition, studies have shown that saturation of tissues with nitrogen under pressure up to 4 atm does not adversely affect fish, and even the human body.

Sources, information used in the preparation of the application:
1. Semenov B.N., Ershov A.M. Scientific basis of food production.

 2. Application N 61-29688, Japan, M. Cl. A 23 B 4/00, claimed 03.03.85., Publ. 07/08/86.

Claims (2)

 1. A method of storing live fish in an airtight container by adding a gaseous preservative to the tank, characterized in that the tank is pre-filled with sea water, and nitrogen gas is used as the preservative.  2. The method of storing live fish in a sealed container according to claim 1, characterized in that sea water is added to live fish in a ratio of 2: 1, and nitrogen gas in a ratio of 1: 5 to fish.