Method for preserving and transforming algae by lactic acid fermentation, lactic acid-fermented juice obtained according to method and use of algae

Abstract

The invention consists essentially of a method for lactic acid fermentation of fresh algae, which can be natural or inoculated under pH control and advantageously under anaerobic conditions, and which makes it possible to produce both ready-to-eat algae in the form of vegetables and fermentation juices that can be drunk directly by animals or mixed with animal feed. After pH stabilization, the obtained algae and fermentation juice are separated.

Description

Field of the Invention

[0001] The present invention generally relates to the field of preservation and transformation of algae, in particular for use in human, animal or plant food or cosmetics.

[0002] It relates to a new method for transforming freshly harvested algae by lactic acid fermentation, in particular in a marine environment.

[0003] The main object of the present invention is to provide a simple, rapid and as natural as possible method, which can optimally extract the natural properties of algae, especially seaweeds.

[0004] All types of seaweeds are suitable for the present invention. These seaweeds include: Gracilaria verrucosa, Chondrus crispus, Himanthalia elongata, commonly known as sea bean, Laminaria saccharina, Laminaria digitata, Undaria pinnatifida, Palmaria palmata, Ulva lactuca, commonly known as sea lettuce, Ulva armoricana, Ulva intestinalis, Solieria Chordalis, Porphyra umbilicalis, Fucus visiculosus, Ascophyllum nodosum, Saccharina Japonica, commonly known as kombu seaweed, Sargassum, Macrocystis pyrifera, Asparagopsis taxiformis, Alaria esculenta, Alaria marginata, commonly known as wakame. Background Art

[0005] Generally speaking, the quality of fresh algae has been recognized as food, such as for human food or animal feed, or for use in cosmetics and plant treatment. Thus, algae have been harvested and consumed by humans and animals worldwide, and have also been used as soil conditioners, for example in the form of seaweeds.

[0006] Algae are also harvested or cultivated to extract alginates, agar, and carrageenan, which are collectively referred to as gelling substances of hydrocolloids (mainly used as thickeners in foods, pharmaceuticals, and nutritional preparations, etc.) or algal colloids used as food additives. The food industry utilizes their gelling, water retention, emulsifying, and other physical properties. Agar is widely used in foods such as confectionery, meat, and poultry-based products, desserts and beverages, and molded foods. Carrageenan is used in dressings and sauces, health foods, and as a preservative in meat and fish products, dairy products, and bakery products.

[0007] In addition, seaweeds are sought after and exploited for their high nutritional content in health-beneficial vitamins, proteins, trace elements, omega-3 and omega-6 fatty acids, etc.

[0008] Since the early 1980s, algae have been approved for consumption as vegetables in France. Only a limited number of "vegetable" algal species benefit from this approval. Their sale is subject to strict regulatory requirements, mainly concerning their heavy metal and iodine content.

[0009] To date, edible algae have been mainly stabilized by using brining or drying.

[0010] As described, for example, in application WO2013 / 045931, ensiling or lactic acid fermentation has been carried out on freshly harvested seaweeds. Ensiling or lactic acid fermentation is a traditional vegetable process and thus can be applied to algae, aiming to preserve algae for a long time while providing sensory (texture, taste) and nutritional benefits.

[0011] The finished product is interesting for several reasons, especially in terms of taste: lactic acid-fermented algae are tender, slightly crispy, and their texture and taste are very pleasant. In addition, lactic acid-fermented algae retain all of their vitality and nutritional properties, especially their high magnesium and vitamin C content. The properties of lactic acid bacteria also improve their digestibility. The transformation carried out by the bacteria improves the digestibility.

[0012] Compared with other methods developed in the past for transforming fresh algae, including drying, then dehydration, storage in saturated salt water, bleaching, then salting, and treatment by mixing with ash, the main advantage of the lactic acid fermentation method is that any undesirable pathogenic microorganisms present in the natural biological environment are destroyed during fermentation, and lactic acid bacteria are not only preserved but also develop in their growth.

[0013] However, the method for lactic acid fermentation of fresh algae for consumption as food needs to be further improved, especially to enable the algae to be stored for a long time without spoiling, and without uncontrolled changes in their texture or appearance, especially their color.

[0014] Furthermore, there is a growing demand for animal feeds that are more efficient and / or reliable than those currently available. Substitutes for synthetic products used in animal husbandry and agriculture are also being sought.

[0015] Accordingly, there is also a need to find solutions for modifying the lactic acid fermentation of fresh algae to provide natural animal feeds that are more efficient and / or reliable than those currently available.

[0016] The aim of the present invention is to meet these needs at least in part. Summary of the Invention

[0017] To this end, the present invention relates to a method for transforming algae, the method comprising the following steps:

[0018] i) providing algae harvested from an aquatic environment and, if necessary, freezing them;

[0019] ii) washing the algae provided according to step i) with water;

[0020] iii) optionally, cutting or grinding the algae washed according to step ii);

[0021] iv) optionally, providing an inoculum mainly comprising lactic acid-producing bacteria;

[0022] v) inoculating the algae optionally cut or ground according to step iii) with the inoculum provided according to step iv), the inoculum comprising a concentration of lactic acid bacteria sufficient for the growth of bacteria present in the algae so as to carry out the lactic acid fermentation of the inoculum, or the natural lactic acid fermentation of the algae, until the measured pH of the lactic acid-fermented composition has dropped below a predetermined final threshold;

[0023] vi) collecting at least a portion of the obtained lactic acid-fermented juice for human, plant or animal use;

[0024] vii) washing the lactic acid-fermented algae and then storing and collecting the lactic acid-fermented algae for human, plant or animal use.

[0025] The algae provided in step i) are preferably seaweeds selected from one of the following species: Gracilaria, Irish moss, Thalassiosira proschkinae, commonly known as sea bean, Laminaria digitata, commonly known as Breton kombuseaweed, Undaria pinnatifida, Palmaria palmata, Ulva lactuca, commonly known as sea lettuce, Ulva viridis, Enteromorpha intestinalis, Ceramium boydenii, Porphyra umbilicalis, Fucus vesiculosus, Ascophyllum nodosum, Laminaria japonica, commonly known as Kombu seaweed, Saccharina latissima, commonly known as Royal Kombu algae, Sargassum, Macrocystis pyrifera, Asparagopsis taxiformis, Undaria pinnatifida, Alaria esculenta, Costaria costata, commonly known as wakame, or a combination thereof.

[0026] The washing step ii) is advantageously carried out by soaking and bubbling. This improved washing must be considered particularly, especially for the algae to be washed off, i.e., the algae that have been separated / torn from their natural support and harvested when visibly washing up on the beach. This removes unwanted sand, pebbles, and plastic waste. For manually harvested algae, simple washing with water is sufficient.

[0027] This washing step ii) may include a sub-step of bleaching the fresh algae to reduce endogenous flora and promote the development of subsequent inoculation.

[0028] Step iii) is advantageously implemented such that the length of the cut algae is between 0.2 and 5 cm. Based on the type of algae, grinding increases the contact surface between the algae and the ferment, thus promoting the fermentation of the algae.

[0029] Regarding seaweeds:

[0030] - For Thalassiosira proschkinae, commonly known as sea bean, the cutting length is preferably between 2 and 5 cm,

[0031] - For Saccharina latissima, commonly known as Royal Kombu algae, the cutting length is preferably between 0.2 and 1 cm,

[0032] - For Laminaria digitata, the cutting length is preferably between 0.2 and 1 cm,

[0033] - For Undaria pinnatifida, the cutting length is preferably between 0.5 and 2 cm.

[0034] The lactic acid bacteria are preferably selected from one of the following species: Lactobacillus plantarum, Leuconostoc mesenteroides, Lactobacillus lactis, Lactobacillus zeae, Lactobacillus casei or Lactobacillus paracasei, Lactobacillus harbinensis, Leuconostoc kimchii, Lactobacillus delbrueckii, Lactobacillus rhamnosus, Lactobacillus harbinensis, Streptococcus thermophilus, Propionibacterium or a combination thereof.

[0035] Advantageously, the inoculation step v) is carried out using a combination of Leuconostoc mesenteroides and Lactobacillus lactis or Lactobacillus zeae.

[0036] Even more advantageously, the inoculation rate is between 10 5 and 10 7 CFU / g. Such a rate is a very good compromise between the desired inoculation efficacy and the production cost.

[0037] According to an advantageous embodiment, the method comprises packaging the cut or ground algae in a storage tank and then subjecting them to anaerobic digestion before the inoculation step v).

[0038] According to an advantageous alternative embodiment, the collection step vi) is carried out by racking the lactic acid fermented juice.

[0039] According to this alternative, the method comprises a step of adding a liquid selected from water, water and acid or a combination thereof, the volume of the added liquid being substantially equal to the volume of the racked lactic acid fermented juice, before step vii).

[0040] Preferably, once the liquid has been added and before racking, the method comprises a maceration step lasting between 1 and 20 days, preferably between 1 and 15 days.

[0041] In the method according to the invention, the predetermined final pH threshold is preferably less than or equal to 4.5.

[0042] Once the juice has been collected according to step iv), an advantageous alternative consists of subjecting the lactic-fermented algae, still in its moist state, to a bleaching step in order to stabilize it. The bleaching agent (e.g., bleaching in a water bath), and optionally an acid, optionally combined with a temperature increase, can act by oxidation or reduction. This bleaching step can reduce the content of certain elements that may be most soluble after fermentation. To recover them, filtering the bleaching bath can be considered.

[0043] Another object of the present invention is the use of the lactic-fermented algae collected in step vii) of the previously described method for human consumption.

[0044] The present invention also covers the use of the lactic-fermented juice collected in step vi) of the previously described method as a palatability enhancer for animal feed, particularly for sheep, cattle, or pigs or poultry, or as a colorant, flavoring, and / or foaming agent, or emulsifier in human food or animal feed and cosmetics.

[0045] The present invention also covers the use of the lactic-fermented juice collected in step vi) of the previously described method (optionally mixed with the lactic-fermented algae collected in step vii) of the previously described method) as a plant stimulant for plant production and / or improving soil quality. For example, the lactic-fermented juice or a mixture with lactic-fermented algae can be used to spread the topsoil or directly sprayed onto the soil.

[0046] The present invention also covers the use of the lactic-fermented juice collected in step vi) of the previously described method in pharmacology.

[0047] Thus, the present invention essentially consists of a method for lactic fermentation of fresh algae, which can be natural or inoculated under pH control and advantageously under anaerobic conditions, and which enables the simultaneous production of ready-to-eat algae in vegetable form and a fermented juice that can be drunk directly by animals or mixed with animal feed. After pH stabilization, the obtained algae and fermented juice are separated.

[0048] The lactic fermentation can be natural or require inoculation based on the type of algae.

[0049] In fact, the inventors have observed that certain algae species, such as Saccharina japonica, undergo natural lactic fermentation once the algae are subjected to a certain heat. The change in texture indicates that the fermentation has started. This observation can be confirmed by measuring the pH, especially after grinding the sample. This is lactic fermentation because the inventors were able to observe the production of acid. Generally, under certain heat conditions, the inventors have been able to observe the natural fermentation of Saccharina japonica within two days.

[0050] Inoculation can be used to accelerate or trigger natural lactic acid fermentation.

[0051] The duration of the lactic acid fermentation process is adjusted based on the type of fresh algae to be processed, its desired final texture, and the juice to be obtained. For the latter, color, odor, and / or viscosity are indicators of the final degree of fermentation.

[0052] In this method, the algae can be cut or ground.

[0053] Cutting increases the contact surface area for fermentation between the algae and the ferment.

[0054] Grinding is preferred when trying to obtain a large amount of juice. For Ulva lactuca, commonly known as sea lettuce, the cutting step can be omitted.

[0055] By means of the lactic acid fermentation method according to the invention, by-products are systematically and directly obtained, namely ready-to-eat algae in the form of lactic acid-fermented vegetables and especially the juice that can be directly consumed by animals. As previously mentioned, once collected, these by-products can be mixed and directly used for human, plant, or animal feed.

[0056] According to the inventor, the results of obtaining the nutritional quality of the algae and the juice are highly reproducible for a very large number of algae species (especially seaweeds).

[0057] The invention described previously has many advantages, including:

[0058] - A simple, rapid, and as natural as possible method, thus enabling the best extraction of the natural properties of algae, especially seaweeds, for the wide applications of the finally obtained lactic acid-fermented juice and / or algae;

[0059] - An "ecologically responsible" method because it requires very little energy, especially because no refrigeration is needed as all steps of the method can be carried out at room temperature.

[0060] - An "ecologically responsible" method that allows the algae to be stabilized and stored for several months while maintaining their properties.

[0061] By referring to the following drawings, additional advantages and features will become apparent upon reading the detailed description, which is illustrative and not restrictive. Brief Description of the Drawings

[0062] Figure 1A and 1B shows an overview of the necessary steps of the algae lactic acid fermentation method according to the invention.

[0063] Figure 2 shows a longitudinal cross-sectional view of an embodiment of the fermenter used in the lactic acid fermentation method according to the invention.

[0064] Figure 3 and Figure 4 is shown in curve form the monitoring of the fermentation pH of examples of algae (respectively Thalassiosira elongata and Saccharina) during the method according to the invention. DETAILED DESCRIPTION

[0065] Throughout the application, the terms "inlet", "outlet", "upstream", "downstream" should be understood in relation to the direction of circulation of the algae to be treated in the device implementing the method according to the invention.

[0066] Although not shown, the device can continuously implement the method according to the invention, i.e. from the feed hopper into which fresh algae are poured at the start of the method to the tank / container for storing and collecting the algae and fermentation juice obtained at the end of the method after lactic acid fermentation. For example, one or more conveying means, in particular conveying means with belts, can be arranged in the device between two positions for implementing the individual steps of the method.

[0067] Now in combination with Figure 1A and 1B describe an embodiment of the method according to the invention.

[0068] Step i): The seaweed arrives directly from the harvesting site in the marine environment into the device, where it is fresh and unwashed. One of the inherent advantages of this method is that it does not require pre - transport using refrigerated trucks. Of course, it can still be frozen at the start of the method, especially if it has been harvested for some time before implementing the method according to the invention.

[0069] This fresh algae is poured into a feed hopper, which can be standard.

[0070] During this step i), the de - shelling step i1) can be carried out in a de - sheller, which can be standard. This de - shelling makes it possible to regulate the feed rate of the algae cutter to be used subsequently and, where applicable, continue to visually sort any undesirable elements, such as parasitic algae, optionally crustaceans present in the algae, such as periwinkle, or others.

[0071] Step ii): Then the algae are washed. This washing consists of rinsing with fresh water and can remove any traces of sand from the algae. Preferably, this washing can be carried out inside the de - sheller itself.

[0072] Step iii): The algae are cut into calibrated lengths.

[0073] Upstream of the cutting machine, a conveyor belt with a gentle slope can be used to pour the algae and directly feed it into the machine. This prevents the algae leaving the shelling machine from aggregating / forming clumps, i.e., mixing together and becoming denser, which may adversely affect the quality (uniformity, precision) of the cutting.

[0074] The cutting length to be performed is carefully selected based on the type of algae to be fermented.

[0075] In fact, the cutting performed increases the contact surface between the algae and the lactic acid ferment used, while preserving the morphological characteristics of the algae, which are important for its quality as food.

[0076] For all seaweeds known to the inventors, the cutting lengths currently envisaged are between 0.2 and 5 cm.

[0077] Step iii1): Once the cutting has been completed, the cut algae are conveyed to at least one tank or container that serves as a storage, inoculation, and collection area.

[0078] Figure 2 Examples of storage, inoculation, and collection containers are illustrated.

[0079] The container 1 comprises a tank 10 that internally delimits a volume in which a mixture M of cut algae and water is stored, and then stored together with the ferment according to the subsequent lactic acid fermentation step. The tank 10 can be a rigid plastic box with side walls and a waterproof base, for example, a rigid plastic box sold under the trade name sold rigid plastic box.

[0080] The volume of the mixture present in the tank 10 is covered by a plate 2 that forms a ballast on the free surface. The plate 2 is advantageously made of a non-oxidizing material. At the stage of step iii), in order to create the surface ballast, the tank 10 is preferably filled with water to about 20 to 40% of the weight of the stored algae. The ballast plate 2 also forms a sealing layer that prevents surface oxidation.

[0081] In addition, the tank 10 is preferably sealed above the plate 2 by a lid 3. Advantageously, a waterproof membrane can be applied to the lid 3 to limit gas exchange with the outside.

[0082] A cock 4 is arranged at the bottom of the tank 10 to drain the lactic acid fermented juice by gravity or pumping at the end of the process.

[0083] Step iv): During the cutting process, an inoculum mainly containing lactic acid-producing bacteria is prepared.

[0084] For this purpose, the ferment is quantified and rehydrated.

[0085] For example, the fermentate is diluted in physiological water at 20 / 25 °C for 30 min to rehydrate it and obtain sufficient distribution.

[0086] When initially providing a completely dehydrated fermentate, the fermentate is rehydrated in fresh water containing 0.9% salt for 1 hour to avoid osmotic shock.

[0087] Several fermentates can be used and they are mixed together beforehand. The fermentates include Lactobacillus plantarum, Leuconostoc mesenteroides, Lactobacillus lactis, Lactobacillus zeae, Lactobacillus casei or Lactobacillus paracasei, Lactobacillus harbinensis, Leuconostoc kimchii, Lactobacillus delbrueckii, Lactobacillus rhamnosus, Lactobacillus harbinensis, and Streptococcus thermophilus.

[0088] Step v): Then the algae can be inoculated in a container, for example, in the container Figure 2 described in detail in the reference.

[0089] For this purpose, the inoculum provided in step iv) is mixed with the algae and water stored in the container to obtain the mixture M to be lactic acid fermented.

[0090] The inoculum is quantified to obtain a lactic acid bacteria concentration for bacterial growth present in sufficient algae to enable its lactic acid fermentation. The inoculation rate is between 10 5 and 10 7 CFU / g. For Thalassiosira elongata, a particularly suitable strain is Lactobacillus plantarum with an inoculation rate of 10 6 CFU / g. Generally, the mixture M in a given container contains cut algae, the fermentate rehydrated according to step iv), and salt (preferably in a proportion of 1 to 3% by weight of the algae), as well as non-chlorinated fresh water (preferably in a proportion of 10 to 100% by weight of the algae).

[0091] This inoculation step can occur very rapidly after harvesting fresh algae, usually between 24 and 48 hours after harvesting.

[0092] According to the present invention, lactic acid fermentation is monitored regularly, and the lactic acid fermentation continues until the pH of the measured lactic acid fermented composition is lower than a predetermined final threshold. Preferably, this pH should be less than 4.5, preferably less than 4.2. At a pH above about 4.2, 4.3, there may be a risk of pathogenic bacteria, and in applicable cases, there may be unreported palatability problems.

[0093] Figure 3 The pH change of a mixture with Thalassiosira elongata algae cut to a length between 0.5 and 1.3 cm is shown.

[0094] This curve shows that the pH is induced by lactic acid fermentation and the pH stabilizes over time.

[0095] Therefore, when the pH is stabilized below the threshold, the lactic acid fermentation time according to the present invention is considered to be completed in order to be able to provide the algae as a food product.

[0096] The method can be optimized to more quickly reduce and stabilize the pH value of the same algal species.

[0097] Generally, the choice of bacterial strain determines the pH level. The anaerobic level also has an impact, thus selecting a suitable storage container.

[0098] For example, as Figure 3 shown, for the alga Thalassiosira elongata, when the pH is stabilized between 3.8 and 4.2, the algae can be collected by separating the algae from the lactic acid fermented juice as described below.

[0099] According to the method of the present invention, the required lactic acid fermentation time also depends on the texture of the algae required for subsequent consumption.

[0100] Table 1 below summarizes the inventors' feedback on the texture of two algal species over time.

[0101] [Table 1]

[0102]

[0103]

[0104] When collecting the algae for packaging, the lactic acid fermentation step v) is stopped.

[0105] Step vi): Before collecting the algae, at least some of the obtained lactic acid fermented juice is collected.

[0106] After the pH of the juice has been checked again, the juice is separated from the algae. Color, odor, and viscosity are also indicators of the fermentation carried out.

[0107] Preferably, the juice is drawn off by gravity or pumping, especially from the bottom of the tank 10 via the cock 3.

[0108] Generally, it is drawn off in the form of fermented juice between 5% and 40% of the total volume of the mixture M.

[0109] Preferably, the drawn-off volume is replaced by substantially the same volume of water with the pH maintained at a predetermined threshold.

[0110] Step vi1):Before extracting the lactic acid-fermented juice from the storage, filter the extracted lactic acid-fermented juice to retain the suspended organic components. For example, a standard stainless-steel filter with a very fine mesh (usually between 0.5 and 0.8 mm) can be used. Appropriate filtration systems can also be envisaged to recover specific active molecules in the juice.

[0111] Step vi2) :Then package the filtered juice. This can be done in small cans or barrels (usually 20 L) or in larger barrels (usually 220 L). The juice can also be packaged in IBCs (Intermediate Bulk Containers), which are tank containers with a large unit volume (usually 1000 L) and are commonly used for storing and transporting liquids.

[0112] For the tests conducted on the tested algal species, the storage time can be up to 6 months at room temperature with a valid period. It is even conceivable to store for up to 12 months in a suitable barrel.

[0113] The collected and stored juice can be used directly or indirectly for animal, plant, or human consumption.

[0114] The inventors have conducted tests on the juices obtained from different algal species.

[0115] The juice obtained from Laminaria digitata is highly foaming and can be applied in cosmetics and human nutrition.

[0116] The juice obtained from Ulva lactuca (sea lettuce) is foaming and can be applied as a palatability enhancer and food supplement in animal nutrition.

[0117] The juice obtained from Palmaria palmata has a very strong purple color and can be used as a natural coloring agent.

[0118] The lactic acid-fermented algae and juice obtained from Cladophora prolifera, Saccharina latissima (royal kelp), and Laminaria digitata have antioxidant, emulsifying, and aromatic properties. To exert the antioxidant properties, the inventors believe that the juice should be concentrated.

[0119] Step vii) :Once the lactic acid-fermented juice has been extracted, wash the lactic acid-fermented algae, store the lactic acid-fermented algae in a buffer tank, and collect them.

[0120] More precisely, pour the lactic acid-fermented algae into a hopper, gently rinse with fresh water, and, if necessary, dehull before rinsing. Then discharge the lactic acid-fermented algae into a container. The container can be one with a perforated wall Type of container. This discharging process removes as much lactic acid as possible from the algae to interrupt the fermentation process as much as possible. Preferably, during fermentation, the algae can be mixed into the juice for anaerobic homogenization and then transferred to a container used for buffer storage.

[0121] To stabilize the algae and thus prevent the growth of harmful bacteria, organic white vinegar in 5% fresh water or 0.8% citric acid can be added to the packaging volume to reach pH 3, and keep the packaged algae intact at room temperature for at least 6 months, which defines the shelf life of the algae. A liquid with a pH between 2 and 3 can be used instead of water to obtain the required stability of the packaging.

[0122] The algae can be packaged in small cans or barrels (usually 10L) or in larger barrels (usually 220L).

[0123] As an example of the above method, the alga Thalassiosira elongata is cut into lengths between 0.5 and 1.3 cm.

[0124] Then it is salted in an amount of 1 to 10% relative to the weight of the cut algae.

[0125] The cut and salted algae are stored in a closed can at a temperature of 10 to 30 °C and individually weighed by a plate that is about 10% of the weight of the algae contained in the can.

[0126] At this room temperature, inoculation is carried out in the following order:

[0127] - Inoculate the primary heterofermentative fermentation with a mixture of Leuconostoc mesenteroides at 5×10 5 per gram of algae and Lactobacillus brevis at 5×10 5 per gram of algae;

[0128] - Measure the decrease in acidity of the mixture to a pH of about 4.5;

[0129] - Inoculate the secondary homofermentative fermentation with Lactobacillus plantarum at a quantity of 10 6 bacteria per gram of algae until a pH of 4 is reached, which corresponds to a duration of about 6 days.

[0130] The inventors carried out further tests.

[0131] At the end of the juice extraction step, the lactic acid-fermented algae collected and thus separated from the juice are pressed and dried in a dryer.

[0132] This drying can be carried out in the temperature range of 40 °C to 100 °C.

[0133] The dried algae are then ground / micronized to obtain a lactic acid-fermented algae powder with effective functional and nutritional properties.

[0134] Tests with lactic acid-fermented sea beans dried to 88% dry matter and micronized to a size between 0.3 and 0.8 mm showed a water absorption capacity 15 times higher.

[0135] This natural biodegradable absorbent composed of dried and micronized algae can represent an interesting plant-based alternative to food additives (carboxymethyl cellulose (E466), sodium alginate (E401), pectin (E440), gum arabic (E414), guar gum (E412), modified starches (E1404, E1412, E1414), carrageenan (E407), alginic acid (E400)). These additives are also used in various industries (cosmetics, hygiene products, etc.).

[0136] Without going beyond the scope of the present invention, other alternative ways and improvements can be envisaged.

[0137] If in the illustrated embodiment, the container is used simultaneously for storing the algae before inoculation, for lactic acid fermentation, and for the collection step, it is possible to envisage having one or more tanks for storing the algae before inoculation and one or more other tanks for lactic acid fermentation and for collecting the lactic acid-fermented algae and juice.

[0138] As a lactic acid fermentation container, a tank of the IBC type can be used, which is equipped in such a way with valves or cocks for withdrawing the lactic acid-fermented juice by gravity or by pumping.

[0139] The embodiment shown above corresponds to the inoculated Stichosiphon elongatus.

[0140] For certain algae species, the inoculation step can be omitted, and thus the pre-quantification of the ferment and then the rehydration can be omitted.

[0141] In fact, as Figure 1A shown, natural lactic acid fermentation can be sufficient between the cutting step and the container storage step.

[0142] This natural lactic acid fermentation can involve, for example, Saccharina japonica, which ferments with its endogenous bacterial flora.

[0143] Figure 4 A curve showing the pH of the pure natural fermentation of Saccharina japonica in the previously described method is shown. After checking that the stable pH of the juice is less than 3.2, the juice is also separated from the algae. Color, odor, and viscosity are also indicators of the maturity of this algae stored in fermentation.

[0144] For the lactic fermentation of Ulva lactuca (sea lettuce), oxygenation can be carried out using an open tank and, if necessary, stirring can be carried out using a bubbler arranged within the volume of the fermentation mixture. It can be preserved using seawater or fresh water containing 3.5% salt. To obtain a lactic-fermented juice with suitable properties, fresh water is preferably used to obtain an osmotic shock and tenderize the sea lettuce to facilitate the action of lactic acid bacteria, thereby dissolving the algae while producing little or no H2S gas. For this lactic fermentation of Ulva lactuca, the inventors have tested Lactobacillus harbinensis and Leuconostoc kimchii as promising strains. After checking that the stabilized pH of the juice is less than 4.2, the juice is separated from the algae. Color, odor, and viscosity are also indicators of the maturity of this algae stored in fermentation. For Ulva lactuca, the inventors plan to mix the algae and the obtained juice to form a nutritious mud.

[0145] In addition to or instead of a sealing plate above the lactic-fermented mixture, a gas (such as CO2 or nitrogen or others) can be circulated on the free surface of the mixture.

[0146] Within the scope of the present invention, various types of equipment can be tested and implemented to optimize the extraction, separation, and concentration of the obtained by-products (lactic-fermented juice and algae). For example, the juice can be concentrated and / or filtered through various mechanical systems (atomization, ultrafiltration, centrifugation, tangential, etc.). The choice of system preferably depends on the degree of transformation of the active ingredients required to be obtained. The active ingredients present in the lactic-fermented juice vary based on the variety and strain of the ferment used.

[0147] In addition, enzymes can also be added, especially when the variety of algae makes it difficult for the inoculated bacteria or fermentation strains to act. For example, endoglucanase and pectinase can be added to transform green algae: due to their rapid action, these enzymes can release the elements required by lactic acid bacteria and initiate fermentation without producing hydrogen sulfide (H2S). The use of enzymes with specific actions can also be considered to improve the quality of the lactic-fermented juice. For example, these specific enzymes can reduce the heavy metal content in the juice.

[0148] To reduce the heavy metal content of the juice, the use of microalgae in a photoreactor can also be envisaged.

[0149] In addition to the applications already described for the algae and the lactic-fermented juice collected at the end of the process, the following broad uses can be envisaged.

[0150] Algae for lactic acid fermentation:

[0151] A / Human food:

[0152] Manufacturers are increasingly seeking plant-based alternatives to animal proteins and reducing chemical additives or even replacing them with natural extracts.

[0153] The inventors carried out tests by mixing 30% lactic acid-fermented sea kidney beans obtained by the method according to the invention with minced beef to obtain a meat loaf.

[0154] These tests showed that the nutritional value of the meat loaf, characterized by the Nutri-Score in France, was improved without altering the taste and with a reduction in production costs.

[0155] The inventors also carried out tests by mixing lactic acid-fermented sea kidney beans obtained by the method according to the invention with sausage meat.

[0156] These tests showed that the prepared mixture had preservative properties, making it a reliable alternative to nitrites currently in use.

[0157] B / Animal feed, especially for sheep, cattle, pigs or poultry:

[0158] The lactic acid-fermented algae obtained by the method according to the invention can be used as a nutritional raw material, a flavoring factor, a conditioning agent or an absorbent. For example, the lactic acid-fermented algae can be mixed with cattle feed to improve the balance of its microbiota and the performance of its digestive metabolism, and thus improve the quantity and quality of the milk produced.

[0159] Furthermore, it is conceivable to add the lactic acid-fermented algae obtained by the method according to the invention in pharmaceutical doses, especially in large doses: indeed, the texture and nutritional quality of the algae can improve the action of the drug on animals.

[0160] It is also conceivable to use the lactic acid-fermented algae, especially in a moistened state, as part of an animal feed ration to improve the quality of the meat (ω-3 fatty acids).

[0161] Furthermore, the inventors have carried out encouraging tests by mixing the lactic acid-fermented algae collected by the method according to the invention to obtain the optimal density of the substrate for insect larvae.

[0162] Further tests are currently being carried out with lactic acid-fermented algae that have been dried and micronized by the method according to the invention, which have been mixed with aquaculture feed (fish meal) to provide a bioavailable plant alternative and improve the quality of the fish meat, the water quality of the farm and reduce mortality.

[0163] Finally, for plant biostimulation, the inventors believe that different varieties of lactic acid-fermented algae obtained by the method according to the invention should be tested by mixing them with biochar, with the aim of improving growth through water regulation and the availability of nutrients required by plants and soil organisms.

[0164] Lactic acid-fermented juice:

[0165] A / Human food:

[0166] The inventors believe that mixing the lactic acid-fermented juice obtained according to the present invention into sports drinks can increase the intake of metabolites.

[0167] Tests on using the juice obtained according to the present invention in ham to reduce or even replace nitrite are about to be carried out.

[0168] In addition, depending on the concentration of the emulsifying active ingredient, the juice obtained according to the present invention can be a substitute for egg white, such as aquafaba (chickpea juice), which is commonly used in cooking and baking, especially in vegan and vegetarian diets, as a substitute due to its foaming and binding abilities. The inventors also believe that it should be envisioned to use the juice obtained according to the present invention instead of the commonly used egg white on top to achieve a vegan decoration on the bun. The inventors also plan to test the juice obtained according to the present invention in bread and cookies to replace additives and improve texture and / or crispness and avoid breakage during cookie making.

[0169] B / Animal feed, especially for sheep, cattle, pigs or poultry:

[0170] The inventors believe that the lactic acid-fermented juice obtained according to the present invention, as a beverage, should be able to reduce the heat stress of animals when the temperature is high in the livestock farm. Animals can reduce their feed consumption, which has a negative impact on growth, milk production, meat quality, reproduction, and general health. The lactic acid-fermented juice with hydration potential and palatability obtained according to the present invention is a solution whose effects should be directly tested on the farm.

[0171] Another envisioned use of the lactic acid-fermented juice obtained according to the present invention is to hydrate poultry while avoiding the formation of biofilms in liquid feed systems, due to the antibacterial properties of the juice.

[0172] Finally, the inventors believe that the lactic acid-fermented algal juice obtained according to the present invention can also provide other advantages, including:

[0173] - Improving animal growth and performance by supplying essential nutrients (such as amino acids, vitamins, and minerals),

[0174] - Strengthening the immune system by supplying certain algal-specific polysaccharides with immunostimulatory properties,

[0175] - Reducing oxidative stress,

[0176] - Improving digestive health, especially prebiotics and postbiotics derived from lactic acid fermentation, which play a beneficial role in the gut microbiota.

Claims

1. A method for converting algae, the method comprising the following steps: i) Providing algae harvested from an aquatic environment, freezing if necessary; ii) Washing the algae provided according to step i) with water; iii) Optionally, cutting or grinding the algae washed according to step ii); iv) Optionally, providing an inoculum mainly containing lactic acid-producing bacteria; v) Inoculating the optionally cut or ground algae according to step iii) with the inoculum provided according to step iv), the inoculum containing a concentration of lactic acid bacteria sufficient for the growth of bacteria present in the algae to perform lactic acid fermentation of the inoculum, or natural lactic acid fermentation of the algae, until the measured pH of the lactic acid-fermented composition has dropped below a predetermined final threshold; vi) Collecting at least a portion of the obtained lactic acid-fermented juice; vii) Washing the lactic acid-fermented algae and then storing and collecting the lactic acid-fermented algae.

2. The method according to claim 1, wherein the algae provided in step i) is a seaweed selected from one of the following species: Gracilaria, Chondrus crispus, Thalassiosira elongata, commonly known as sea beans, Laminaria digitata, commonly known as Brittany kelp, Undaria pinnatifida, Palmaria palmata, Ulva, Solieria chordalis, Porphyra umbilicalis, Fucus vesiculosus, Ascophyllum nodosum, Laminaria japonica, commonly known as kelp, Saccharina latissima, commonly known as royal kelp, Ulva lactuca, commonly known as sea lettuce, or a combination thereof.

3. The method according to claim 1 or 2, wherein step iii) is carried out such that the length of the cut algae is between 0.2 and 5 cm.

4. The method according to any one of the preceding claims, wherein the lactic acid bacteria are selected from one of the following species: Lactobacillus plantarum, Leuconostoc mesenteroides, Lactobacillus lactis, Lactobacillus zeae, Lactobacillus casei or Lactobacillus paracasei, Lactobacillus harbinensis, Leuconostoc kimchii, Lactobacillus delbrueckii, Lactobacillus rhamnosus, Lactobacillus harbinensis, Streptococcus thermophilus or a combination thereof.

5. The method according to any one of the preceding claims, wherein the inoculation step v) is carried out by a combination of Leuconostoc mesenteroides and Lactobacillus lactis or Lactobacillus zeae.

6. According to the method described in claim 5, the inoculation rate is between 10 5 and 10 7 CFU / g.

7. The method according to any one of the preceding claims, the method comprising, before the inoculation step v), packaging the cut or ground algae in a storage tank and then subjecting the cut or ground algae to anaerobic digestion.

8. The method according to any one of the preceding claims, the collection step vi) being carried out by pumping the lactic acid-fermented juice.

9. The method according to claim 8, the method comprising a step of adding a liquid selected from water, water and acid or a combination thereof before step vi), the volume of the added liquid preferably being substantially equal to the volume of the pumped lactic acid-fermented juice.

10. The method according to claim 9, the method comprising an impregnation step for a period between 1 and 20 days, preferably between 1 and 15 days, once the liquid has been added and before pumping.

11. The method according to any one of the preceding claims, the predetermined final pH threshold being less than or equal to 4.

5. Use of the lactic acid-fermented algae collected in step vii) of the method according to any one of the preceding claims for human consumption. Use of the lactic acid-fermented juice collected in step vi) of the method according to any one of claims 1 to 11 as a palatability enhancer for animal feed, in particular for sheep, cattle or pigs or poultry, or as a colorant, flavorant and / or foaming agent, or emulsifier in human food or animal feed and cosmetics. Use of the lactic acid-fermented juice collected in step vi) of the method according to any one of the preceding claims 1 to 11, optionally mixed with the lactic acid-fermented algae collected in step vii) of the method according to any one of the preceding claims 1 to 11, as a plant stimulant for plant production and / or improving soil quality. Use of the lactic acid-fermented juice collected in step vi) of the method according to any one of the preceding claims 1 to 11 in pharmacology.

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