FR2963877A1 - Method for shucking and cleaning sea product e.g. patellidae in pharmaceutical industry, involves cleaning flesh in bath of refrigerated sea water so as to obtain sea product free from impurities - Google Patents

Abstract

The method involves allowing rapid freezing (A) of living animals at low temperature, without using brine or fresh water, in order to kill the living animals by cold. The living animals are subjected for thawing process (B) at a low temperature so as to obtain dead animals, and detach shells (3) from the dead animals. Flesh and the shells of the dead animals are separated (C) by brewing in a bath of refrigerated sea water. The flesh is cleaned (D) in the bath of the refrigerated sea water so as to obtain a sea product free from impurities.

Description

The present invention relates to a method for the shelling / shelling and washing / cleaning of seafood, in particular molluscs and in particular gastropods and bivalves. It was designed and developed to treat gastropods known as crepidula belonging to the family Calyptraeidae, and whose scientific name is Crepidula fornicata.

Crepidula are gastropod molluscs that live in coastal ecosystems, particularly in sheltered, shallow areas with low current. These molluscs, which have a shell length of four to six centimeters, have a thin, pinkish-brown shell with a slight spiral wound, and a septum or calcareous septum, which separates the visceral mass from the foot, which enables it to adhere to a support. In crepidulae, as in most gastropods, their body or visceral mass is protected by an integumentary structure called mantle. The attachment of the body or visceral mass of the animal to the septum is also provided by the pedal muscles.

The genus Crepidula has about twenty species, most of which live in the waters of North and South America. The crepidula lives in colonies / chains formed of a superposition of several individuals, on average less than a dozen, firmly fixed to each other.

In France, Crepidula fornicata is an introduced and invasive species. It is present throughout the French coast, and especially with large populations 25 on almost all of the Western Channel and Atlantic foreshore.

The crepidulae have peculiarities in the field of their nutrition. They are recognized as suspensivorous, feeding on phytoplankton by filtration, and both provided with a radial system that allows grazing on the biofilm of the substrate. Part of the phytoplankton and other food particles ingested and not assimilated by the crepidula are carried to the vicinity of the mouth in the form of a dark brown food mucous cord.

The colonization of the French coast by Crepidula fornicata causes an increase in the siltation of the sites where it settles. Its optimal biotope coincides with that of edible shells, such as oysters, mussels, scallops and scallops. She is an active competitor for the food of oyster flocks.

Chilean coastal populations have long been known to consume several types of crepidulae, such as Crepidula dilatata, Crepidula fecunda, and especially Calyptraea (Trochita) trochiformes species exploited and marketed.

In France, the nutritional value of crepidula appeared to be unknown. However, the flesh of Crepidula fornicata was tested and their sensory, organoleptic and nutritional characteristics corroborated a high acceptability of this novel food for humans.

Until today in France, the dehulling / shelling of crepidula has been a hindrance to all the projects of valorization of this marine gastropod in view of the low yield, of the labor necessary very important, and the problems of the obtaining a clean flesh, free of impurities. It should be noted that a process for dehulling marine molluscs has already been proposed in French Patent No. 08 55158 filed on 28/07/2008. This process uses freezing in a brine bath and then warms the animals to a temperature of 15 ° C. This method has the disadvantage of not respecting the cold chain, which can pose problems for the use of flesh in the food industry.

The purpose of using a fast and dry freezing of live animals is to preserve the quality of the flesh by avoiding the formation of too many or too large ice crystals that would be susceptible to damage the tissues.

One objective of the invention is to exploit the crepidulae, and to value the different economic interests of the flesh and shells. The flesh is edible and can be used by the agri-food industry, nutrition and health. Crushed shells can be valued as a calcium amendment in agriculture, pharmaceuticals and cosmetics.

To do this, it is necessary to easily deconstruct / deconstruct 35 large quantities of crepidula at low cost and on an industrial scale that allows the production of clean flesh and shells, separately. The present invention provides an economical, fast and simple design method for separating shell flesh from crepidulae, through the use of fast and dry freezing without breaking the cold chain. The ultrasonic emitter treatment provides an optimal solution to the cleaning problem, in particular grit removal.

According to the invention the method follows the following steps:

a) rapid freezing at low temperature, dry, without brine or soft water, suitable for killing animals by cold,

(b) defrosting at low temperature so as to obtain dead animals, chilled, detached from their shells,

C) separation of the flesh and shells by mixing in a bath of chilled sea water, so as to obtain the flesh on the one hand, and the shells on the other hand,

d) cleaning the flesh in a refrigerated seawater bath equipped with an ultrasonic emitter, so as to obtain a product free of impurities.

Moreover, according to a certain number of additional, nonlimiting features of the invention:

The duration of freezing carried out in step (a) is between 5 minutes and 30 minutes and the temperature is between -5 ° C. and -25 ° C.

in step (b), the animals are defrosted and maintained in chilled seawater at a temperature of between -2 ° C. and + 4 ° C.

in step (c), the meat is separated from its shell by stirring with jets of refrigerated pressurized seawater, at a temperature maintained between -2 ° C. and + 4 ° C., during a duration between 10 minutes and 30 minutes.

in step (d), the flesh is kept in a bath of chilled seawater at a temperature of between -2 ° C. and + 4 ° C., the duration of exposure of the animals to ultrasound in this device being a few minutes. 4 - the flesh is rinsed in a bath of sea water diluted with fresh water whose salinity is between 10% o and 20% o so as to obtain a product of good taste quality for human nutrition. the shells extracted in step (c) are subjected to a second treatment corresponding to step (c).

the process is carried out continuously with conveying means, the animals to be treated circulating one after the other successively. - Use of the method applied in particular to crepidulae.

A possible and preferred embodiment of the invention will now be described with reference to the appended FIG. 1, which is a diagram with block diagrams illustrating the method.

The molluscs to be treated are alive. They were harvested by dredging on a shellfish bottom, sandy-muddy and / or rocky, in the case of crepidulae.

In a preferred form of the invention, the crepidulae are washed to rid them of sands, plant debris and other potential wastes. This initial washing is symbolized by the block (1) of Figure 1. This operation can be performed directly on the boat that harvested the animals, using jets of sea water and / or a washer / classic seashell screener. The animals, still alive, are then poured into a rapid freezing tunnel symbolized by the block (A) of FIG. 1. By way of indication, the freezing temperature is between -5 ° C. and -25 ° C. The animals to be treated are transported upstream to downstream of said device using a conveyor belt. The duration of the passage is between 5 minutes and 30 minutes. This operation can advantageously kill the animals gradually frozen.

The thawing device symbolized by the block (B) of FIG. 1 has the objective of obtaining chilled animals, dead, detached from their shells by disuning the mantle and breaking the pedal muscles. As such, the animals are kept in a bath of chilled seawater at a temperature between -2 ° C and + 4 ° C. The device for separating the flesh and shells symbolized by the block (C) of the Figure 1 aims to separate the flesh of their shell by stirring in a bath of refrigerated seawater. Because of this brewing / jetting exerted by jets of refrigerated pressurized seawater, the animals collide, while progressing in the device (C) which has the effect of finishing the detachment of the mantle and the muscles pedal. The sliding of the soft parts is facilitated by the presence of a wide opening of the limestone partition of said shells.

Said separation device (C) advantageously consists of jets of refrigerated pressurized seawater, advantageously maintained at a temperature between -2 ° C and + 4 ° C. The animals are dumped continuously by means of a conveyor belt. This is a food-grade mat with fine mesh (for example square mesh of 6x6mm). The residence time of the animals in this device is between 10 minutes and 30 minutes.

It is likely to make a second passage of the shells in the device (C), represented by the block (2) of Figure 1, and / or an independent device (C), without departing from the scope of the invention. This operation is advantageously used so as not to exceed a 2% of unshelled / shelled animals.

The shells separated from their flesh (block 3) are extracted from the device (C) and poured into a suitable receptacle, for later recovery.

The flesh is extracted from the device (C) by overflow and transported by means of a conveyor belt of the food type, and advantageously poured into the device (D) symbolized by the block (D) of FIG.

The flesh cleaning device (D) makes it possible to obtain a quality product free of impurities. Said device is composed of a refrigerated seawater tank equipped with an ultrasonic transmitter. The temperature of the refrigerated seawater is preferably between -2 ° C and + 4 ° C. The duration of stay of the flesh in said device is a few minutes.

A particular embodiment of the invention provides a 20/10 millimeter thick stainless steel sheet emitter in the form of a bar or box of approximately 800 × 500 × 70 millimeters, and deposited at the bottom of the device (D). .

Advantageously, the operating frequency of the transmitter is between 25mHz and 40mHz, while the power can vary between 200 and 5,300 Watts.

The purpose of the presence of an ultrasonic transmitter in chilled water is to produce ultrasonic vibrations by creating so-called cavitation phenomena which ensure a mechanical work inside the device (D) thus allowing the cleaning of flesh. The generator with stainless steel cable of approximately 2.5 meters is located outside the device (D) allowing the power supply of the transmitter with a coaxial cable exit of 5 meters.

The use of this type of apparatus allows a constant cleaning power without resorting to agitation, and an optimal cleaning and precision, without risk of breakage or deterioration of the flesh.

Naturally, and particularly in the installation of the generator, the ultrasonic frequency and the power can be modified, without departing from the scope of the invention.

Rinsing the flesh in a refrigerated seawater bath with controlled salinity is advantageously used to obtain a product of good taste quality for human nutrition. This rinsing makes it possible, in addition to reducing the salinity of the flesh of the crepidulae, to eliminate the black deposit that forms at the time of said shucking process. This black deposit (mucous cord dissolved in water) is not disturbing in terms of sanitary quality since it is edible, but it can impair the good presentation of the flesh in the case of food consumption. by the man.

The clean flesh thus obtained can be used in the agri-food industry in the state or after processing, as well as in the field of nutrition and human health.

The present invention further comprises a pumping system ensuring the recycling of said used liquid, ie seawater, connected to the device for the shelling and cleaning of animals (devices (A), (B), ( C), (D)).

The recycling of seawater is carried out through a filtration system and is associated with a means of controlling temperature and salinity.

According to the invention, the shells thus cleaned of their flesh are advantageously milled by a grinder, with a suitable particle size for use as a calcium-enriching agent in agriculture, as well as in the pharmaceutical industry and the cosmetology industry.

The process of the invention can be applied to various other species of marine gastropod molluscs, among which may be mentioned in non-exhaustive form: patellids, fissurilids, haliotids, muricidae, whelks, littorinids, acmaeidae, trochids, nacellinids, etc. Among the bivalves, one can quote in non-exhaustive form: the mytilidae, the pectinidae, the cardids, the venerids, the mactrids, the ostreids, the solenids, the phorids, the ensidés, etc.

Claims (9)

REVENDICATIONS1. A process for breaking up and cleaning seafood, in particular molluscs and especially gastropods and bivalves, which comprises the following steps: a) rapid freezing at low temperature, dry, without brine or fresh water, suitable for killing the fish animals by cold, (b) defrosting at low temperature so as to obtain dead animals, chilled, detached from their shells, (c) separation of flesh and shells by mixing in a bath of chilled sea-water, so as to obtain the flesh on the one hand, and the shells on the other hand, d) cleaning the flesh in a refrigerated seawater bath equipped with an ultrasonic emitter, so as to obtain a product free of impurities. 2. Method according to claim 1, characterized in that the freezing time used in step (a) is between 5 minutes and 30 minutes and that the temperature is between -5 ° C and -25 ° C. 3. Method according to any one of the preceding claims, characterized in that in step (b) the animals are defrosted and kept in refrigerated seawater at a temperature between -2 ° C and + 4 ° C. 25 4. Method according to any one of the preceding claims, characterized in that in step (c) the flesh is separated from their shell by stirring exerted by jets of refrigerated pressure seawater, at a temperature maintained between -2 ° C and + 4 ° C for a period of between 30 minutes and 30 minutes. 5. Method according to any one of the preceding claims, characterized in that in step (d) the flesh is maintained in a bath of refrigerated seawater at a temperature between -2 ° C and +4 ° C, and that the duration of exposure of animals to ultrasound in this device is a few minutes. 5 6. Method according to any one of the preceding claims, characterized in that the flesh is rinsed in a bath of sea water diluted with fresh water whose salinity is between 10% o and 20% o so to obtain a product of good taste quality for human nutrition. 7. Method according to any one of the preceding claims, characterized in that the shells extracted in step (c) are subjected to a second treatment corresponding to step (c). 10 8. Method according to any one of the preceding claims, characterized in that the process is carried out continuously with conveying means, the animals to be treated circulating one after the other successively. 9. Use of a method according to any one of the preceding claims, applied in particular to crepidulae.