Technical Field of Invention

The present invention relates to a method for the preparation and/or large-scale production of high-viscosity liquid food compositions. The said method is comprised of the steps of adding the oil ingredients of the composition to the mixture by direct oil injection method, and ultra-high temperature processing using the infusion UHT system.

State of the Art

Food compositions are dietary supplements, that is, they intend to meet a certain part or whole of the daily nutritional requirements. Clinical nutrition products, on the other hand, refer to compositions developed specifically for a particular disease or a particular age group as well as supporting the diet Clinical nutrition primarily focuses on the prevention of dietary changes in patients with chronic diseases and conditions and the diagnosis and management of such diseases. Normally, individuals take the necessary nutrients into their bodies through regular daily diets. However, illness, disorder, stress and similar conditions may prevent the body from getting sufficient nutrients through diets alone. In such cases, a specifically formulated dietary supplement may be required. This supplement may be in the form of clinical nutrition. Clinical nutrition not only aims to maintain a healthy energy balance, but also provide patients with sufficient amounts of nutrients, such as protein, fat, carbohydrates, water, vitamins and minerals.

Clinical nutrition and nutritional care have gained wide clinical and scientific interest, particularly in the recent decade. Increasing knowledge on the relationship between nutrition and metabolic disorders in chronic and acute diseases has spurred rapid developments in the design, development and clinical application of dietary supplements.

The ingredients of the food compositions of the present invention and/or clinical nutrition products may vary depending on the target patient group. Among these products, high-protein liquid or semi-liquid food compositions take an important place. Clinical nutrition products with high protein content are described, for example, in WO 2021/167562 Al and WO 2021/162659 Al documents. Products with a high protein content result in some difficulties throughout production due to their high viscosity, inasmuch as the production technology used for the preparation of sterilized liquid compositions has already been optimized for the milk. However, products with high protein content have a very high viscosity compared to milk. In addition, products with high protein content have the risk of protein contamination, and this risk is required to be minimized to ensure the desired shelflife.

EP 2092832 Al describes a method for UHT treatment of the milk with high protein content The said method is comprised of comprises the following steps: high pasteurization and homogenization of the previously fat-standardized milk; addition of transglutaminase enzyme to pasteurized and homogenized milk; incubation at 4°C-40°C for 2-36 hours; and high-density heat treatment of the obtained mixture, wherein the milk is stabilized by the addition of a stabilizer selected from a phosphate salt, a citrate salt and a combination thereof.

Another ingredient that is commonly contained in food compositions is fats, mainly the polyunsaturated fatty acids (PUFA). In particular, pediatric compositions contain relatively high concentrations of long-chain polyunsaturated fatty acids to strengthen the immune system and enhance brain development. An example of pediatric compositions containing docosahexaenoic acid (DHA) is disclosed in WO 2021/173096 A2 document

However, especially long-chain PUFAs are more susceptible to oxidation than other ingredients that are commonly contained in food compositions. Due to the chemical structures of these fatty acids, a series of reactions related to carbon-carbon double bonds may occur with the effect of heat and atmospheric oxygen, leading to free radical production. These reactions accelerate in the presence of oxygen and oxidation accelerators (e.g. iron, copper, zinc, etc.). The resulting free radicals may then continue to break down polyunsaturated fatty acids in an auto- oxidation. Thus, fatty acids degrade, resulting in undesirable bad tastes and odors.

These long-chain PUFAs are at risk of oxidation, especially when they are processed at high temperatures during the production phase or during the spray drying process. Also, as a challenge in terms of shelf life, fatty acids may be susceptible to oxidation even during a relatively short storage period after the formula has been hermetically sealed and packaged. The issue of oxidative stability becomes more complex in terms of eliminating the fish flavor especially during the production of food compositions containing fish oils with high amount of DHA and ensuring this flavor not to appear during shelflife.

In the light of this, it is clear that one of the most important challenges in the preparation of food compositions is to reduce oxidation caused by fat content and sedimentation arising out of dry matter (e.g. protein) content in order to provide the desired shelf life. Commonly used in the compositions in the state of the art, the high protein and fat content provides solutions for diet and adjunctive therapy, but it requires the optimization of production.

US 5234702 A discloses a method for controlling undesirable oxidation of polyunsaturated fatty acids in powdered food compositions. According to the method, antioxidants including palmitate, beta carotene and mixed tocopherols are added to the food composition.

In addition to preventing oxidation by adding antioxidants to the mixture, as performed in the above-mentioned document, oxidation may also be minimized by performing the appropriate process steps under appropriate conditions during the production of the food compositions. For example, US 2014186503 Al relates to a method for the preparation of formula milks containing polyunsaturated fatty acids. According to the method, the ingredients of the formula milk are mixed with a microcapsule and the mixture is processed by cooking, heating, pasteurizing or homogenizing, and then filled into a container, wherein the microcapsule comprises an agglomeration of primaiy microcapsules and a loading substance, each individual primary microcapsule having a primary shell, wherein the loading substance is encapsulated by the primary shell.

Despite the current solutions described above, there is still a need for a specific process in the state of the art that will minimize the contact time between oxygen and oils. The most important reason for this is that the production steps need to be optimized according to the desired food composition and its specific fat content. Therefore, it is of great importance to determine the production steps in accordance with the content of the composition.

Ultra-high temperature treatment (UHT), ultra-high heat treatment or ultra-pasteurization are food processing technologies that sterilize liquid foods by heating them up to temperatures above 135°C (275°F) which is required to kill bacterial endospores within 2 to 5 seconds. UHT is most commonly used in milk production as well as in the sterilization of food compositions, fruit juices, cream, soy milk, yoghurt, wine, soup, honey and one-pot meals.

UHT principles are divided into two categories as direct and indirect In direct UHT systems, culinary steam is applied directly to the product, and the product is cooled in a flash cooler. Conventional direct UHT is performed using an injector to apply steam to the product. Today, however, the infusion chamber is preferred to strongly reduces turbulence and contamination. In indirect systems, a heating surface is positioned between steam and product In the indirect UHT systems, conventional system based on plate heat exchangers is used for milk and low viscosity products. Modern indirect UHT systems, on the other hand, use tubes placed in a steam chamber. Depending on the composition to be produced, it is important to select the appropriate system.

In particular, direct UHT systems are preferred because they eliminate the risk of protein contamination in high-viscosity compositions. Steam Injection and Infusion systems are also advantageous because they allow the extension of time between the cleaning activities of production lines used for high-viscosity products.

In the light of the foregoing information and considering the state of the art, it is clear that there is a need for the improvements in the preparation and production of liquid food compositions with high protein and fat content, especially the clinical nutrition products. Therefore, production methods comprising optimized steps for the preparation of high-viscosity food compositions will provide a development and improvement in the technical field. For this purpose, the present invention provides a new method for the preparation of food compositions and clinical nutrition products.

Brief Description of the Invention

According to one aspect, the present invention provides a method for the preparation of food compositions. The said method comprises the following steps:

- mixing water-soluble ingredients,

- adding water to the mixture,

- pasteurization of the slurry,

- adding oil ingredients to the pasteurized mixture by injection,

- performing the UHT treatment using the infusion UHT system, and

- obtaining the food composition.

According to the method of the invention, the water-soluble ingredients are mixed preferably in a vacuum mixer.

According to the method of the invention, the pasteurization is performed preferably between 72°C and 85°C.

According to the method of the invention, the oil ingredients are added to the pasteurized mixture by injection preferably between 30°C and 60°C.

According to the method of the invention, the oil ingredients are stored preferably under nitrogen blanketing before being added to the pasteurized mixture by injection. The method of the invention also preferably comprises the step of encapsulation of the oil ingredients prior to injection.

The method of the present invention also preferably comprises performing the homogenization between the steps of adding the oil ingredients to the pasteurized mixture by injection and performing the UHT treatment using the infusion UHT system.

The method of the present invention also preferably comprises performing flash cooling following the step of the UHT treatment using the infusion UHT system.

The method of the present invention also preferably comprises performing a second homogenization following the flash cooling step.

Short Description of Figures

Figure 1 shows the flowchart of mixing the water-soluble ingredients according to one embodiment of the method of the present invention.

Figure 2 shows the flowchart of pasteurization according to one embodiment of the method of the present invention.

Figure 3 shows the flowchart of preparing the oil ingredients/mixture according to one embodiment of the method of the present invention.

Figure 4 shows the flowchart of direct oil injection and infusion UHT according to one embodiment of the method of the present invention.

Detailed Description of the Invention

The present invention relates to a method for the production of food compositions and clinical nutrition products. The said products are in the form of liquid drinks suitable for oral consumption and tube feeding and are characterized by their high viscosity.

The method for the preparation of the food compositions provided according to the invention comprises the following steps:

- mixing water-soluble ingredients,

- adding water to the mixture,

- pasteurization of the slurry,

- adding oil ingredients to the pasteurized mixture by injection,

- performing the UHT treatment using the infusion UHT system, and obtaining the food composition.

The inventors, surprisingly, have noticed that viscosity increase and oxidation are minimized when they apply the process steps in that order.

In particular, the production steps of clinical products that have compositions significantly different from milk should be carefully designed. For example, high dry matter or protein content causes high viscosity and protein contamination problems. Since protein contamination is also a factor that increases viscosity, if and when these problems cannot be prevented, the product with the desired viscosity characteristics cannot be obtained and the production system cannot be used efficiently. High viscosity also causes heat treatments to be carried out with poor heat transfer coefficient at the production stage.

The selection and design of the UHT system/facility are of great importance so as to utilize the production line of the said high viscosity compositions efficiently and produce a product with a shelflife of 12 months. In order to ensure a shelflife of at least 12 months, development of flavor loss, oil separation, sedimentation and viscosity increase should be minimized. This is possible, among other parameters, by choosing the right UHT system during production.

The selected UHT system and the order at which the UHT is applied during the process are also important for efficient production (long working time between cleaning activities) as mentioned above. This is possible by minimizing fouling and viscosity increase during production.

For the above-mentioned reasons, according to the method of the invention, the infusion UHT system is preferred for the UHT treatment. The said system is advantageous because it is useful for the sterilization of the products with high viscosity (e.g. high protein content) and minimizes the risk of protein contamination as well as it makes the production lines of the said products operable for a longer period of time without the need for cleaning.

In infusion UHT, the liquid product is subjected to heat-treatment at Ultra High Temperature (up to 142 to 145°C) for a very short time (approx. 2 seconds). The aim is to kill all vegetative cells and eliminate any existing spores that may start growing during their shelflife.

In order to prevent the oxidation of fatty ingredients with high oxidation potential, such as polyunsaturated fatty acids, which are commonly contained in the composition of clinical nutrition products, the oil ingredients are added to the mixture by injection. According to the step called "Direct Oil Injection” of the method, the oils are stored under nitrogen to prevent a long-term contact between the oil ingredients of the composition and the air (oxygen) and added directly to the mixture by injection before the UHT treatment Adding oils to the mixture by injection not only prevents oxidation that may occur during production but also extends the shelf life. It is also important to add each ingredient in an appropriate order during the production of compositions. In this context, the inventors have realized that it is advantageous to add the oil ingredients just before the UHT treatment This is especially true for critical (i.e. having high risk of oxidation during production and formation of odor and flavor during shelf life) ingredients such as DHA or eicosapentaenoic acid (EPA).

Food compositions suitable for production using the method of the present invention are in liquid form that can be administered orally or by feeding tube. Viscosity is also important in this respect. In addition, it is aimed to keep the mineral load and osmolality at a low level.

According to the invention, the water-soluble ingredients are mixed at the first step of the method preferably in a vacuum mixer. Utilization of a vacuum mixer to dissolve powdered ingredients has many advantages such as eliminating the risk of severe foaming that poses a high risk in milk proteins, providing rapid homogeneous mixing and not requiring additional powder removal systems thanks to the vacuum mixer that collects the powder. In addition, mixing under vacuum prevents the leakage of oxygen into the mixture.

The mixture is pasteurized to eliminate pathogens and extend shelf life. Pasteurization is carried out at temperatures below 100°C (212°F), preferably between 72°C and 85°C.

The oil ingredients are added to the pasteurized mixture by injection preferably between 30°C and 60°C. The inventors have observed that adding the oil ingredients of the food composition by direct oil injection method in the said temperature range is advantageous in terms of minimizing the oxidation.

The said oil ingredients/mixture are/is stored preferably under nitrogen blanketing before being added to the pasteurized mixture by injection.

According to the method of the invention, the said oil ingredients are included in the composition preferably in an encapsulated form. Thus, the method of the invention preferably comprises the step of encapsulation of the oil ingredients prior to injection. The encapsulation is particularly advantageous when using oil ingredients having fish flavor and odor, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Encapsulation is effective in preventing oxidation and odor formation during both production and shelflife.

The method of the present invention also preferably comprises performing the homogenization between the steps of adding the oil ingredients to the pasteurized mixture by injection and performing the UHT treatment using the infusion UHT system. The said step of the method is advantageous in such a way that it ensures a proper incorporation of oil ingredients added by oil dosing before heat treatment (infusion UHT) to the mixture. The homogenizer enables the micronization of the oil droplets to provide as much surface as possible to prevent oil separation during shelflife.

The method of the present invention also preferably comprises performing flash cooling following the step of the UHT treatment using the infusion UHT system. Flash cooling removes all oxygen from the product and reduces the risk of oil oxidation during storage. Flash cooling is also advantageous in that it removes oxidative tastes/bad flavors that occur in the mixture prior to UHT.

A known disadvantage of flash cooling in the art is that it removes some of the flavor added to the product According to the present invention, this problem is overcome by slightly overdosing the flavor.

The method of the present invention also preferably comprises performing a second homogenization following the flash cooling step. Due to flash cooling, oil separation may occur in the mixture to the some extent. Thus, the second homogenization step of the method according to the invention is advantageous in that it re-homogenizes and stabilizes the oil droplets.

According to the method of the present invention, preferably the UHT treatment is not carried out immediately after mixing and intermediate storage tanks are used. This is because it is required to establish a mineral balance and stabilize the pH before heat treatment In case the said balance and stabilization cannot be achieved, there is a risk of poor heat stability, contamination and reduced operating time. The use of intermediate storage tanks also enables for a better work flow as it allows the mixture to be prepared one day before the UHT treatment

The inventors have recognized that the foregoing steps and their order are effective and advantageous in the production of high-viscosity food compositions with high protein content. The steps of the method of the invention are effective both for the efficient use of the production facility and obtaining products with the desired viscosity and shelf life. In addition, the method of the invention ensures sufficient homogenization of the oil ingredients and prevents oxidation during production and shelf life. Reduction of sedimentation and oxidation is the contributing factor to the stability of compositions.

The method of the present invention is also advantageous in that it allows to obtain food compositions with low osmolarity and osmolality, ensuring higher patient compliance. An embodiment of the method of obtaining the food composition of the present invention is described in detail in the Examples below.

EXAMPLES

1. Mixing Water-Soluble Ingredients

The water-soluble ingredients were mixed in a vacuum mixer. Then, water from water tanks was added to this mixture. Water and water-soluble ingredients were taken into mixing tanks and then mixed. The slurry was subjected to preheating and cooling, respectively (Figure 1).

2. Pasteurization

The slurry in the mixing tanks was subjected to regenerative heating. Then, pasteurization was carried out at a temperature between 72°C and 85°C. After pasteurization, the mixture was subjected to regenerative cooling. Subsequent cooling continued until the mixture reached a temperature of 5°C to 10°C. Finally, the cooled mixture was transferred to intermediate storage tanks (Figure 2).

3. Preparation of Oil Ingredients

The oil ingredients were transferred to the oil storage tanks via the oil transfer pump. The oils were kept under nitrogen blanketing to minimize oxidation. The oil ingredients under nitrogen blanketing in the oil storage tanks were mixed by the means of slow mixers. Oils were preserved in this way until the direct oil injection (Figure 3).

4. Direct Oil Injection and Infusion UHT

The slurry in the intermediate storage tanks was heated from 5°C-10°C to 70°C-85°C. The oil ingredients in the oil storage tanks were added to the slurry by injection. With the direct oil injection carried out at 30°C to 60°C, the contact of the oils with oxygen was minimized. Then, homogenization was carried out at a pressure of 300 bar. After homogenization, UHT treatment was performed using the infusion system. Here the temperature was increased from the range of 70°C-85°C to 142°C for a very short time. Then, flash cooling was performed to reduce the temperature of the mixture to 70°C. Using an aseptic homogenizer, the mixture was homogenized for a second time at a pressure of 300 bar and the oils were integrated into the mixture. The mixture was then cooled to 20°C and transferred to aseptic storage tanks. Thus, the food composition was obtained as a result of the method of the present invention (Figure 4). Nitrogen blanketing was also used in aseptic storage tanks if required by the obtained food composition content The food compositions suitable for both oral and tube feeding were packaged preferably in 200 ml HDPE bottles.