Field of the Invention

The present invention relates to a production method for obtaining plant milk or plant milk product. In particular, the present invention relates to a method of obtaining plant milk or plant milk product, wherein ultrasonic homogenization and UV-C pasteurization are performed. The present invention also relates to plant milk or plant milk product obtained using a pulp separated from a cold press oil production process as a raw material, and a production method for obtaining said plant milk or plant milk product.

Background Art

Milk, which is one of the most essential beverages, is a highly preferred nutritional source with its essential nutrients such as fat, protein and carbohydrates, as well as other components that are important for metabolism such as calcium, selenium, riboflavin, vitamin B12, pantothenic acid (vitamin B5). Due to some health problems and lack of resources, consumption of animal milk is not possible and/or sufficient for all individuals.

Consumption of animal origin milk and dairy products causes allergic reactions in some persons. Animal milk allergy is known as a kind of food allergy that causes various health problems from digestive problems that affect many babies to skin diseases.

In addition, persons with lactose intolerance lack enzyme lactase, which digests milk sugar, i.e., lactose. Therefore, lactose in the consumed dairy products cannot be fully digested, which causes stomach discomfort. Lactose intolerance, especially seen in elderly persons, is a common disease across the world.

Another concern in the consumption of animal dairy products is the presence of additives such as antibiotics, hormones and genetically modified substances in the animal feeds used. Undesirable substances such as antibiotic residues penetrate into the system of individuals who consume dairy products obtained from animals fed with such animal feeds, and cause health problems in the long term. In addition, persons who follow an intense diet program prefer lower calorie beverages instead of animal milk. Persons diagnosed with high cholesterol are recommended to consume plant milk and plant milk products that do not contain cholesterol and have a lower fat ratio, instead of consuming animal milk containing cholesterol and fat.

On the other hand, it is known that natural resources perish very quickly in the production of animal products such as animal milk. A very serious amount of water resources are used for the production of animal dairy products. The energy required for the production of milk substitutes such as plant milk is less than that required for the production of conventional animal milk. In addition, it is regarded as an important advantage that plant milk can be produced at any time according to demand and as much as desired. Considering the natural resources that are depleting day by day, the importance of dairy products that can be used instead of animal dairy products stands out.

Therefore, in recent years, plant milks obtained from fruits such as soy milk, rice milk, coconut milk, almond milk, and cashew nut milk, cereal products, oil seeds, and legumes have become the focus of the food industry.

Plant milks available in the market cannot fully meet the needs of consumers for protein drinks such as plant-based dairy products, due to the lack of sensory properties, poor nutritional content, lack of cream due to low fat content, and physical instability.

Intensive efforts are still made to improve the organoleptic, nutritional and functional properties of plant milk alternatives. In plant milks that reach to a significant number of consumers as animal milk substitutes, it is among the most basic objectives to ensure physical and chemical stability, remove the odor and aroma originating from the raw materials used, and extend the shelf life.

For all the above-mentioned reasons, there is a need for plant milk or plant milk products with a long shelf-life obtained from lactose-free, cholesterol-free, low-fat, high-protein, low- calorie plant sources.

Objects of the Invention:

Principal object of the present invention is to obtain a plant milk or plant milk product that does not deteriorate during its shelf life.

Another object of the present invention is to ensure that the resulting plant milk or plant milk product preserves both the physical properties and nutritional value for a long shelf life. Another object of the present invention is to obtain a plant milk or plant milk product in which phase separation is prevented, agglomeration and creaming problems are eliminated.

Another object of the present invention is to improve the physical stability of plant milk or plant milk product.

Another object of the present invention is to increase the microbial quality of the product by inactivating microorganisms in plant milk or plant milk product.

Another object of the present invention is to obtain a protein-rich beverage by minimizing protein denaturation in the structure of plant milk or plant milk product.

Another object of the present invention is to implement a low-cost, fast and practical method in the production of plant milk or plant milk product, which eliminates the need for a pretreatment performed in traditional methods.

Still another object of the present invention is to obtain a plant milk or plant milk product, which can be used as a substitute for animal milk and is Theologically similar to animal milk.

Summary of the Invention

The present invention describes a method for producing plant milk or plant milk product, wherein homogenization process is performed in said method and said homogenization process is carried out by ultrasonic method.

Detailed Description of the Invention

The present invention describes a method for producing plant milk or plant milk product, wherein homogenization process is performed in said method and said homogenization process is carried out by ultrasonic method.

According to the present invention, the production of plant milk and plant milk product includes extraction, filtration, addition of auxiliary components, homogenization and pasteurization steps.

Plant milk is a heterogeneous system in which oil globules are present, wherein oil and water are dispersed within each other. According to Stoke's law, fat globules with a smaller particle size move more slowly, while particles with a larger particle size come closer to each other to agglomerate. Since the particle size is large in traditional plant milks, agglomeration problem is inevitable. On the other hand, due to the presence of large particles, plant milks leave a gritty mouthfeel. In addition, due to the low-fat content in the structure of plant milk, the problem of lack of cream is observed. Physical instability, poor sensory properties due to its gritty texture, and lack of cream due to low fat content are among the main problems.

When the particles in plant milk are of different sizes, precipitation is observed in particles with larger particle size, whereas particles with smaller particle size accumulate at the top. In other words, as a result of the phase separation depending on the particle size, fat globules collect at the upper surface while other macromolecules precipitate on the bottom.

At the bottom of the packaged products where agglomeration is seen, sedimentation starts, which continues during storage, and thus, shaking before use is a must. Sedimentation is indicative of physical instability.

As can be inferred herein, one of the main problems in plant milk is physical instability. Physical instability directly affects the stability of the product and therefore its quality.

In animal and plant milks, homogenization process is performed to prevent phase separation and agglomeration. With the homogenization process, the particle size of the fat globules in the milk decreases so that the fat globules are homogeneously dispersed in the emulsion. In this way, the formation of cream on the surface of the milk is also prevented.

The main aim in the homogenization process in the production of plant milk is to reduce the particle size in order to ensure the stability of emulsion. Given the small size of the particles in the structure of the milk, the particles in the emulsion are prevented from rising upwards and agglomerating on the upper surface and/or settling to the bottom. With the dispersion of the fat globules in the structure of plant milk in the emulsion without agglomeration, desired physical stability is achieved in the product.

For this purpose, different techniques are applied, i.e., the homogenization process, which is carried out by mechanical or thermal methods including applications such as high pressure or high temperature, is used in the production of both animal and plant milk.

The most important problem in the known homogenization methods is the deterioration of the protein structure in plant milk as a result of the thermal and/or mechanical methods applied. As known, as a result of some physical and chemical processes, the secondary, tertiary and quaternary structures in the protein are transformed into primary structures, i.e., denatured. As a result of denaturation of proteins, some problems occur such as a decrease in nutritional value, an increase in undesired aroma compounds, and a deterioration in sensory properties of foods. Depending on the denaturated protein, the solubility of the protein in water decreases and its biological activity is reduced. Protein structures allow the fat and water particles in plant milk to adhere to each other and form a bond. As a result of the denaturation of the protein structure, the bond between the oil and water particles weakens, resulting in a physical stability problem.

High pressure homogenization involves the application of high pressure instead of high temperature. In this method, it is aimed to reduce the particle size by applying pressure. Due to the application of lower temperatures than the heat treatment, there is no serious deterioration in the protein structure during this process, however, the homogenization performance is not at the desired level, so precipitation is observed in the structure of the milk. In addition, since the temperature is low during high pressure homogenization, the formation of microorganisms cannot be prevented and an additional sterilization process is needed. Since the sterilization process involves high temperature applications, protein loss is inevitable as a result of denaturation of the protein in the structure of milk.

In summary, homogenization methods performed in the homogenization of milk either do not yield the desired results, or cause some problems. Therefore, an effective homogenization method is needed in order to ensure the physical stability of plant milk.

From this requirement, an ultrasonic homogenization method is used in the homogenization of plant milk and plant milk product in the present invention. The size of the particles in the plant milk is reduced by means of ultrasonic sound waves. The sound waves applied in this method are evenly distributed throughout the emulsion. As a result, the molecules in the emulsion vibrate and said vibration is transferred to the neighboring molecules and continues. This effectively reduces the size of all particles in the system. As a result of a reduction in the particle size, the stability of the product increases, and its viscosity decreases. Otherwise, if the particle size cannot be reduced sufficiently, the viscosity of plant milk increases, and the problem of agglomeration is observed. High viscosity and agglomeration are the most obvious indications that the product is physically unstable. Since plant milks find use as animal milk substitutes, it is desired that they have low viscosity like animal milks and that they are similar to animal milks in terms of rheological properties. The differences in rheological properties in plant milks mainly depend on the mass of fat they contain, the amount of oil droplets or colloidal substance, and the amount of thickening agents, if used. Processability of plant milks is associated with their functional properties and sensory characteristics, and how their viscosity changes with the shear rate; therefore, they must be produced in a controlled manner in order to obtain the desired properties. According to an embodiment of the invention, the power used in the ultrasonic homogenization process performed in the production of plant milk is in the range of 300-500 W, preferably in the range of 380-420 W. The power used is important in terms ensuring the stability of the physical structure through the breakdown the particle size, and homogenization of the milk.

According to another embodiment of the invention, the temperature applied in the ultrasonic homogenization process is in the range of 35-55°C, preferably in the range of 40-50°C. Said temperature values indicate the reactor temperature. By keeping the temperature in a certain range, protein denaturation was observed at a minimum level, and at the same time the formation of microorganisms was prevented. In this way, the desired level of microbial quality is achieved and the need for a sterilization step, which is a kind of heat treatment, is eliminated.

According to another embodiment of the invention, the duration of the ultrasonic homogenization process performed in the production of plant milk may vary in the range of 1-5 minutes. Preferably, a process time of 2-3 minutes is preferred. Given that a certain range of temperature is also applied in said homogenization process, the temperature of the milk will increase as the time increases. In this case, protein loss occurs due to protein denaturation. In order not to cause an increase in temperature, if the time is kept too short, homogenization cannot be realized sufficiently, and physical stability cannot be achieved at the desired level. Therefore, the process time of homogenization determined according to the invention both provides effective homogenization and does not cause protein denaturation.

Because of the large particle size of the fat droplets in the plant milk, the plant milk is prone to rapid flocculation. As a result of the ultrasonic homogenization method performed according to the invention, it is observed that particles in plant milk can be effectively downsized. It is observed that the average particle size of the plant milk produced according to the invention is below 500 nm. The average particle size described herein is detected by Scanning Electron Microscope (SEM) and Zetasizer Nano devices.

In the ultrasonic homogenization method described by the present invention, it is observed that the physical stability of the plant milk is significantly improved due to the reduction of particle size, through the application of the temperature for a certain period of time and also the use of a certain power. In the plant milk with increased physical stability, problems such as phase separation, sedimentation, cream formation on the surface are not observed. It is observed that aggregation and aggregation problems, which directly affect the physical stability, are experienced when the particle size cannot be reduced sufficiently.

By reducing the particle size as desired, the surface area is also increased. That is, with the ultrasonic homogenization method performed according to the invention, a homogeneous dispersion is achieved and the average particle size is rapidly reduced. The fat globules present in the plant milk emulsion are negatively charged, and thus the product is electronegative. The stronger the electrostatic attraction between the particles, the better the particles adhere to each other. Thus, problems such as agglomeration are prevented and superior physical stability is achieved. Otherwise, if the particle size reduction is not realized for all the particles in the emulsion, particles with larger particle size either precipitate at the bottom or attract other particles towards themselves, which causes agglomeration. This is caused by the fact that the particles cannot hold (attract) each other equally. In the case where the electrostatic attraction force is equal for all particles, no attraction/repulsion of the particles is observed, and a stable product in dispersed state is obtained.

Furthermore, nutritional value of the product is largely preserved since protein loss is minimal in the ultrasonic homogenization process.

On the other hand, it is known that the protein structure allows the fat globules and water particles in the plant milk to adhere to each other. Thus, the bond between oil and water particles is strengthened and the physical stability of the product is achieved. This mechanism indicates that the protein is a component that contributes to stability. Consequently, given that the protein structure is preserved in the ultrasonic homogenization method performed according to the present invention, with said method, the stability of the plant milk and/or the plant milk product is preserved.

According to the present invention, another step in the production method performed for obtaining plant milk or plant milk product is the pasteurization process. In order to ensure microbial quality, microbial degradation must be prevented and the formation of microorganisms must be stopped. According to the invention, an UV-C pasteurization process is performed to ensure the microbial quality of the plant milk or plant milk product. Unlike to the traditional pasteurization methods, UV-C pasteurization is not a high-temperature process. In other words, it serves to preserve the microbial structure of the product without using heat treatment applications. Since it does not involve any thermal applications at an extent to degrade the protein structure, inactivation of microorganisms was achieved in the UV-C pasteurization method without causing deterioration in the protein structure of plant milk. UV-C application can not only reduce the number of bacteria and spores that are not sensitive to thermal pasteurization, but also reduce the number of psychrotrophic bacteria that can be present when the plant milks need to be stored for a long time.

According to the present invention, in the UV-C pasteurization process, which is one of the method steps performed for obtaining plant milk or milk product, the flow rate of milk is in the range of 50-150 ml/min, preferably 100-125 ml/min. Flow rate is the velocity of the plant milk as it passes through the column.

According to another embodiment of the invention, in the UV-C pasteurization process performed for obtaining of plant milk or plant milk product, the temperature is applied in the range of 25-65°C, the temperature range is preferably 45-55°C. This temperature value is the temperature of the reactor where UV-C pasteurization is carried out. Said temperature range ensures effective microbial inactivation without causing protein loss.

According to another embodiment of the invention, the wavelength applied in the UV-C pasteurization process is in the range of 200-280 nm, preferably 253.7 nm.

With the UV-C pasteurization method performed according to the present invention, microorganisms in the plant milk such as E. Coli, s. Typhimurium, Lactobacillus rhamnosus, Salmonella Typhimurium, Saccharomyces cerevisiae, Salmonella enterica, L. Monocytogenes are inactivated.

According to the invention, only ultrasonic homogenization or only UV-C pasteurization can be performed according to the method used in the production of plant milk or plant milk product, or ultrasonic homogenization and UV-C pasteurization processes can be performed in the same process. With the simultaneous application of ultrasonic homogenization and UV-C pasteurization steps in the plant milk production, it is observed that the shelf life of the product is extended. In this way, both physical stability and microorganism inactivation are effectively achieved. According to the invention, in plant milk production, extraction, filtration, addition of components, ultrasonic homogenization, UV-C pasteurization steps are performed respectively.

In the extraction process, the raw material is extracted by adding water to the raw material used. The ratio of raw material to added water is in the range of 1: 1-1: 10.

In the filtration process, the cake and milk part of the ground raw material are separated. As a filter material, a double-layered cheesecloth, a muslin cloth, and various sizes of filter paper can be used. In the step of adding the components, a stabilizer may be used to increase physical stability, an antioxidant may be used to prevent oxidation, and a flavoring and sweetener may be used to improve the taste of the product. Apart from these components, sugar, tricalcium phosphate, sea salt, emulsifier, vitamin, or a combination thereof may be used in the plant milk or plant milk product produced according to the present invention.

According to another embodiment of the invention, in the method performed for obtaining plant milk or milk, the pulp formed in the cold press oil production and then separated is used as a raw material source. In this way, a product with high nutritional value is obtained, and the shelf life of the product is significantly extended.

According to traditional methods, cereals, seeds, legumes such as almonds, hazelnuts, walnuts, black cumin, coconut, pumpkin seeds, peanuts, flax seeds are used as raw materials in the production of plant milk. In this case, the selected raw material must be subjected to a number of pre-treatments such as dehulling, soaking, bleaching, grinding, oil separating. Said pre-treatment process not only causes extra costs but also increases the production cost of plant milk. Also, in case of pre-treatment, since homogenization cannot be realized sufficiently, phase separation, which is one of the most important indicators of physical instability, occurs in the final product.

According to the invention, in the production of plant milk or plant milk product, the pulp separated from the cold press oil production process is used as raw material. In the cold press oil production mentioned herein, flaxseed, pumpkin seed, almond, walnut, hazelnut, black cumin, coconut, or peanut can be used as the starting product. All of the products suitable for cold press oil production can be used as raw material in the production of plant milk obtained according to the invention. Due to the fact that the raw material used according to the invention is the pulp obtained from the cold press oil production process, the need for pre-treatment performed in traditional methods has been eliminated.

The pulp, which is separated from the cold press oil production process and used as raw material in the production of plant milk or plant milk product described according to the invention, is largely free of fat. In this way, the plant milk obtained by using the pulp defined according to the invention has a low-fat content and low calories.

In the present invention, with the use of the pulp separated from the cold press oil process as a raw material in the plant milk production process, the protein content of the resulting milk is quite rich. In the production of traditional plant milk, when the raw materials such as seeds, cereals and legumes are pre-treated, a significant amount of protein in the structure of milk is denatured due to ambient temperature and environmental factors. Since the protein structure is deteriorated in the plant milk produced by subjecting to the pretreatment methods, the protein content decreases, therefore, adhesion/bond formation between fat globules and water cannot be achieved sufficiently and the desired stability cannot be achieved. In the prior art, the protein value of the existing plant milks varies according to the raw material used. For example, the amount of protein in plant milk obtained from almonds ranges from approximately 0.4% to 1.2%, while the protein content of coconut milk ranges between 0.1% and 0.3%. In the plant milk produced according to the present invention, the protein value is at least 2.5%.

Conversely, given that the pulp separated in the cold press oil production process is used as raw material in the present invention, instead of using raw materials that require pretreatment such as seeds, cereals, legumes as raw material for production of plant milk, there is no need for pre-treatments such as thermal and mechanical applications. Also, the raw material used herein is the pulp separated in cold press oil production, i.e., said oil production is prepared by the cold press method that does not involve heat. In this way, no change is observed in the protein structure of the product. Thus, the protein content of the raw material used in plant milk production is quite high.

According to the invention, substances subjected to cold press oil production in order to separate the pulp and use in plant milk production may include almonds, walnuts, hazelnuts, black cumin, pumpkin seeds, flax seeds, coconut, and peanuts. In a more general definition, the pulp of any substances subjected to cold press oil production can be used as raw material of the plant milk to be produced according to the invention.

In the present invention, the plant milk obtained using the pulp separated from the cold press oil production as a raw material may also contain at least one auxiliary substance. Suitable auxiliary substances according to the invention are stabilizers, antioxidants, emulsifiers, flavors, thickeners, sugars, anti-odor agents, vitamins, or a combination thereof.

According to the invention, locust bean gum, gellan gum, carrageenan, or a combination thereof can be used as a stabilizer.

According to the invention, carotenoids, vitamin E, phenolic compounds, ascorbic acid, or a combination thereof can be used as an antioxidant. The antioxidant is preferably ascorbic acid; with the ascorbic acid, the oxidation of fats is effectively prevented.

According to the invention, lecithin, sunflower, or a combination thereof can be used as an emulsifier. According to the invention, vitamin B2 (Riboflavin]), vitamin B12 (Cyanocobalamin), vitamin E (DL-alpha-tocopheryl acetate), vitamin D (Ergocalciferol), or a combination thereof can be used as a vitamin.

Flavors and salt can be used in the plant milk or plant milk product obtained according to the invention. Depending on which raw material the pulp used in plant milk is obtained from, fruit and spice flavors can be used.

The thickening agents that can be used according to the invention are xanthan gum, locust bean gum, gellan gum, Arabic gum, or a combination thereof. Xanthan gum is preferably used as a thickening agent, and it has been observed that optimal consistency properties are achieved even when xantham gum is used at low proportions.

The plant milk or plant milk product according to the invention may also contain sugar, tricalcium phosphate, sea salt, or a combination thereof.

In addition, in the production method of the plant milk obtained according to the present invention, oil can be added to adjust the oil proportion of the final product. Compared to conventional plant milks obtained by p re-treatment, the plant milks according to the present invention that are produced without pre-treatment have a lower fat content. Although low fat content is a preferred feature in the low-calorie diet products category, in some cases, fat is added to achieve the desired taste and sensory properties. Thus, low-fat or whole plant milk is produced, which is both rich in protein and adjustable in fat content.

By fermenting the plant milk obtained by the production method described in the present invention, with the methods available in the art, dairy products such as plant-based kefir, yogurt, cheese, and cream are also obtained.