Method for Producing Greek Yogurt with Enhanced Flavor and Shelf Life Using Deep Sea Water

Abstract

The present invention provides a method for producing Greek yogurt using deep sea water, characterized by comprising the steps of: preparing homogenized pasteurized milk; heating the pasteurized milk to the inoculation temperature of lactic acid bacteria; inoculating the pasteurized milk with lactic acid bacteria and fermenting it; cooling the fermented raw milk; adding deep sea water and stirring to homogenize before separating the whey; separating the whey; and filling and sealing the coagulated product.

Description

Technology Field

[0001] The present invention relates to the field of dairy processing, particularly to the manufacture of yogurt, and to a method for manufacturing Greek yogurt that uses deep sea water as a raw material to improve flavor (sweetness and nuttiness) and texture (softness) and extend the shelf life. Background Technology

[0002] Regular yogurt and Greek yogurt are types of fermented milk products that are rich in nutrients such as protein, lactic acid bacteria, and calcium. They are widely consumed globally, recognized for their various health benefits, including improved gut health, enhanced digestion, and strengthened immunity. In particular, Greek yogurt is a product that has had its whey removed compared to traditional yogurt to increase protein content and viscosity, and it is gaining popularity as a high-protein, low-fat, and low-sugar food. Consequently, consumption has increased significantly in global markets, including Korea, over the past few years, and demand for it as a diet food, high-protein snack, and health food continues to expand.

[0003] However, these types of yogurt inherently have the limitation of a short shelf life. Standard fermented milk products begin to deteriorate in quality within approximately 7 to 10 days of production, with typical issues including excessive acidity due to rancidity, the occurrence of oxidized fat odors, and spoilage caused by the proliferation of unwanted bacteria and mold other than lactic acid bacteria. This process is further accelerated by temperature fluctuations or storage conditions during distribution, and consumers often avoid consuming the product even before it reaches its expiration date due to unpleasant taste and aroma.

[0004] Furthermore, commercially available yogurts and Greek yogurts have limitations in terms of consumer palatability. First, amidst the trend to reduce sugar content, they often lack sweetness, resulting in a bland flavor. Second, in the case of Greek yogurt, the whey removal process tends to result in a texture that is excessively hard or dry, failing to meet the expectations of consumers who prefer a soft and creamy texture. Conversely, some products lack sufficient viscosity, appearing watery and having uneven physical properties, which reduces palatability. In other words, the inability to simultaneously secure a balance between flavor (sweetness and nuttiness) and physical properties (softness and viscosity) is pointed out as a significant problem with current technology.

[0005] Meanwhile, deep sea water is seawater collected from depths of approximately 200 meters or less. It is characterized by the absence of photosynthetic organisms due to the lack of sunlight, low water temperatures, and minimal influx of external pollutants. This deep sea water is rich in major minerals such as magnesium (Mg), calcium (Ca), and potassium (K), as well as trace elements such as zinc (Zn) and selenium (Se). Previous studies have reported that deep sea water possesses various physiological activities, including regulating electrolyte balance in the body, relieving fatigue, and stabilizing blood pressure. Consequently, the food and beverage industry is actively attempting to utilize it as a functional ingredient. In particular, it is known that the mineral composition of deep sea water influences protein structure stabilization and enzyme activity regulation, thereby contributing to the improvement of food flavor and the extension of shelf life.

[0006] However, to date, the utilization of deep sea water has been primarily limited to beverages, health supplements, and some baked goods, and technical examples of its application in the production of fermented milk, particularly Greek yogurt, are extremely rare. While some studies report that deep sea water has a positive effect on the proliferation of fermentation microorganisms, there are almost no cases where shelf life extension, flavor improvement, and texture improvement were simultaneously achieved through the addition of deep sea water during the actual commercial product development stage.

[0007] Therefore, there is a strong demand for the development of technology that can resolve the issues of short shelf life, lack of flavor, and uneven texture inherent in existing yogurts and Greek yogurts, while simultaneously improving product palatability and shelf life by utilizing the mineral composition of deep sea water. In particular, if optimizing the timing, concentration, and fermentation conditions of deep sea water can enhance the sweetness and nutty flavor of yogurt, delay rancidity and spoilage, and improve its smooth texture, this would possess high industrial value as a new food processing technology clearly differentiated from existing technologies. Prior art literature

[0008] 1. Korean Registered Patent No. 10-2259148-0000 (May 26, 2021) The problem to be solved

[0009] The objective of the present invention as described above can be achieved by the following means.

[0010] (1) A method for producing Greek yogurt using deep sea water, characterized by comprising the steps of: preparing homogenized pasteurized milk; heating the pasteurized milk to the inoculation temperature of lactic acid bacteria; inoculating the pasteurized milk with lactic acid bacteria and fermenting it; cooling the fermented raw milk; adding deep sea water and stirring to homogenize before separating the whey; separating the whey; and filling and sealing the coagulated product.

[0011] (2) A method for producing Greek yogurt using deep water, comprising the steps of: preparing homogenized pasteurized milk stored at 2~6℃; heating the pasteurized milk to an inoculation temperature of 35~45℃; inoculating the pasteurized milk with lactic acid bacteria and fermenting it for 3~10 hours; cooling the fermented raw milk to 10~15℃; adding deep water at 5~12% by weight relative to the total mixture and stirring at 150~300 rpm for 5~20 minutes before separating the whey; separating the whey; and filling and sealing the coagulated product.

[0012] (3) In the above (1),

[0013] A method for producing Greek yogurt using deep sea water, characterized in that the above-mentioned lactic acid bacteria are Lactobacillus bulgaricus or Streptococcus thermophilus.

[0014] (4) In the above (1),

[0015] A method for producing Greek yogurt using deep sea water, characterized in that the above-mentioned lactic acid bacteria further comprise at least one selected from Lactobacillus acidophilus (L. acidophilus), Lactobacillus casei (L. casei), Lactobacillus helveticus (L. helveticus), and Bifidobacterium bifidum.

[0016] (5) In the above (1),

[0017] A method for manufacturing Greek yogurt using deep sea water, characterized in that the deep sea water is provided in a concentrated form and added at a ratio of 3 to 5 weight percent.

[0018] (6) In the above (1),

[0019] A method for producing Greek yogurt using deep sea water, characterized in that the above-mentioned whey separation is performed by filtration for 30 to 120 minutes or centrifugation at 1,500 to 3,000 × g for 5 to 15 minutes.

[0020] (7) Greek yogurt made using deep water according to any one of the methods selected from (1) to (6) above. Effects of the invention

[0021] According to the present invention, various mineral components such as magnesium, calcium, and potassium contained in deep sea water interact with proteins and organic acids during the lactic acid fermentation process, thereby significantly improving the flavor of the yogurt. As a result, compared to existing products, the sweetness and nutty flavor are further enhanced, allowing consumers to experience a more satisfying taste.

[0022] In addition, the mineral composition of deep sea water stabilizes the protein structure and gel network, thereby exhibiting the effect of inhibiting fat oxidation and the proliferation of harmful bacteria. Accordingly, the yogurt of the present invention delays rancidity and spoilage after manufacturing, and the shelf life, which is typically only about 10 days, can be extended by at least 5 days. This significantly reduces quality degradation during distribution and storage, thereby increasing its commercial value.

[0023] In addition, the minerals in deep sea water contribute to the rearrangement of casein micelles and the increase in water binding capacity, thereby maintaining the physical properties of the yogurt uniformly and achieving a creamy yet smooth texture. Therefore, the yogurt of the present invention has a consistent viscosity and a smooth texture felt in the mouth, which can effectively resolve the problem of dry or watery textures that were pointed out in conventional Greek yogurt. Brief explanation of the drawing

[0024] Figure 1 is a manufacturing process diagram of Greek yogurt using deep sea water according to the present invention. Specific details for implementing the invention

[0025] The contents of the present invention will be explained in more detail step by step with reference to FIG. 1 below.

[0026] 1. Supply and demand of homogenized pasteurized milk

[0027] The production of Greek yogurt according to the present invention begins with the step of receiving raw milk that has been homogenized and sterilized in a low-temperature state. The raw milk is maintained at 4°C or lower to inhibit microbial growth, and after receiving, it is transferred to a heating process with the shortest possible residence time of 0 to 12 hours, preferably within 6 hours. If necessary, solid content reinforcement (2 to 3% by weight of skim milk powder, etc.) may be carried out immediately after receiving or immediately before heating. The storage tank is equipped with a SUS-based mechanical stirrer to maintain a homogeneous dispersion state of the raw milk.

[0028] 2. Heat to the lactic acid bacteria inoculation temperature

[0029] The supplied raw milk is heated indirectly to 35–45°C, preferably 40–42°C. The heating rate is controlled gradually to ensure microstructural stability before protein denaturation and gel formation, and is maintained uniformly within a temperature deviation of ±1°C. Since the thermal history at this stage affects the micropore size and water binding capacity of the coagulant during subsequent fermentation, stirring (50–100 rpm, preferably 70 rpm) is performed in parallel to prevent dead zones in the tank.

[0030] 3. Addition of lactic acid bacteria and fermentation

[0031] After heating is complete, a starter (lactic acid bacteria) is inoculated and fermentation is initiated. The inoculated strains are preferably based on Lactobacillus bulgaricus and Streptococcus thermophilus, but depending on the purpose of flavor and texture, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus helveticus, Bifidobacterium bifidum, etc., may be used individually or in combination. The inoculation amount is set to 0.01–0.05% by weight, preferably 0.02–0.03% by weight; the fermentation temperature is set to 38–43°C, preferably 40–42°C; and the fermentation time is set to 3–10 hours, preferably 4–8 hours, and most preferably 5–6 hours.

[0032] The criteria for terminating fermentation are defined as a decrease in pH (e.g., 4.4–4.7) or the attainment of titratable acidity (TA), depending on the process objective, and require that the coagulated material be uniform and that the outflow of separated water during water collection is not excessive. During fermentation, low-speed stirring or intermittent stirring is permitted to reduce dissolved oxygen and ensure uniform heat distribution, but excessive shear that causes coagulation breakdown is avoided.

[0033] 4. Cooling

[0034] When fermentation is finished, rapid cooling is performed to delay the progression of acid production in the coagulated material and to stabilize the protein gel structure. At this time, the product temperature is preferably 10 to 15°C, more preferably 12 to 14°C, and the cooling rate is based on 30 minutes to 1 hour, more preferably 45 minutes. Since excessive stirring can cause the collapse of the network structure, stirring is limited to no stirring or ultra-low speed stirring (≤50 rpm). After cooling is complete, the material is immediately transferred to the next process within 0 to 60 minutes, more preferably 15 to 30 minutes, before the whey separation stage.

[0035] 5. Add deep sea water and stir before separating the whey.

[0036] Deep sea water is added to the cooled coagulated material immediately before whey separation to induce mineral-mediated interactions. Both standard and concentrated types of deep sea water may be used, and the addition ratio is 5 to 12% by weight, preferably 8 to 10% by weight, relative to the total liquid. When using the concentrated type, it is applied by converting it to 3 to 5% by weight, preferably 3%. Stirring is performed at 150 to 300 rpm, preferably 200 to 250 rpm, for 5 to 20 minutes, preferably 10 to 15 minutes.

[0037] At this stage, Mg in deep water 2+ , Ca 2+ , K + Trace elements such as [the above] interact with casein micelles to promote water binding capacity and gel network rearrangement, thereby contributing to increased sweetness and nuttiness, a soft texture, and improved shelf life during subsequent whey separation. In principle, the timing of addition is based on immediately before whey separation, but if necessary, modification during cooling immediately after fermentation (e.g., adding 5% immediately after fermentation) is also permitted.

[0038] 6. Whey Separation

[0039] The whey is physically removed from the deep water-treated coagulated material through filtration (drainage mesh, cheesecloth) or centrifugation. The goal is to achieve the characteristic consistency of Greek yogurt, and depending on process conditions, the drainage time can be set to 30–120 minutes, preferably 60–90 minutes, or the centrifugation time can be set to 1,500–3,000 × g for 5–15 minutes, preferably 2,000 × g for 10 minutes. Since the degree of whey separation is directly related to product viscosity and yield, the end point is defined based on pre-verified viscosity / moisture indices (e.g., viscosity within the target range, observation of free water after drainage). Excessive separation should be avoided, as it can cause mealiness and dryness.

[0040] 7. Filling and Sealing

[0041] The coagulated material from which the whey has been removed is transferred to a hygienic filling line and filled into containers at a low temperature (10–15°C, preferably 12°C). The variation in filling volume is managed within ±1%, and airtight sealing is performed using a sealing material that minimizes headspace and has oxygen blocking properties (film / cup with low oxygen permeability). If necessary, a simple degassing process, such as nitrogen purging, may be performed in parallel to contribute to delaying rancidity. Inline quality assurance devices, such as metal detection and weight inspection, are provided.

[0042] 8. Refrigerate

[0043] Sealed products are immediately transferred to a cold storage facility and stored at 2–6°C, preferably 4°C. The initial 24 hours are considered a critical period for structural stabilization and flavor maturation, so it is desirable to maintain a temperature fluctuation of within ±0.5°C. The application of deep sea water according to the present invention exhibits a delay effect on rancidity and spoilage, and is designed to extend the shelf life by at least 5 days compared to the existing shelf life (e.g., 10 days) (set through internal verification tests).

[0044] 9. Shipment (maintaining the cold chain)

[0045] Products are shipped according to the First-In, First-Out (FIFO) principle, and a cold chain (0–10°C, preferably 4°C) is maintained throughout the entire process of loading, distribution, and display. Before transport, inspections of appearance, pH, odor, and sealing status are conducted through random sampling, and continuous monitoring is performed using a temperature recorder during distribution. The final shelf life is scientifically calculated by integrating the results of accelerated harsh condition testing (e.g., storage at 8–10°C) and actual distribution condition testing.

[0046] Hereinafter, the contents of the present invention will be explained more specifically with reference to examples; however, these examples are presented merely to aid in understanding the contents of the present invention and should not be interpreted as limiting the scope of the rights of the present invention.

[0047] [Example]

[0048] [Example 1]

[0049] In this embodiment, Greek yogurt using deep sea water was prepared with basic composition ratios and conditions.

[0050] For the experiment, homogenized pasteurized milk (100 parts by weight) stored at 4°C or below was prepared. The prepared pasteurized milk was heated to 40°C. A starter (0.02 parts by weight) mixed with Lactobacillus bulgaricus and Streptococcus thermophilus was inoculated and fermented for 5 hours. After the fermentation was completed, it was cooled to 15°C or below. Immediately before whey separation, deep water at 5% by weight relative to the total flow rate was added and stirred at 200 rpm for 10 minutes. After stirring, the whey was separated. After filling and sealing the coagulated product, it was refrigerated at 4°C. The final product was kept refrigerated until shipment.

[0051] [Example 2]

[0052] In this embodiment, the flavor and preservation properties were examined by increasing the proportion of deep water.

[0053] For the experiment, pasteurized milk (95 parts by weight) at 4°C or lower was prepared. After heating it to 40°C, a mixed strain of Lactobacillus bulgaricus and Lactobacillus acidophilus (0.03 parts by weight) was inoculated and fermented for 6 hours. After fermentation, it was cooled to 15°C. Just before separating the whey, 10% by weight of deep sea water relative to the total volume was added and stirred at 250 rpm for 15 minutes. Subsequently, the whey was separated, and after filling and sealing, it was refrigerated.

[0054] [Example 3]

[0055] In this embodiment, the interaction with deep sea water was examined by changing the fermentation temperature.

[0056] For the experiment, pasteurized milk (100 parts by weight) at 4°C or lower was prepared. After heating to 42°C, a single strain of Streptococcus thermophilus (0.015 parts by weight) was inoculated and fermented for 4 hours. After fermentation, it was cooled to 12°C. Before separating the whey, 7% by weight of deep sea water was added and low-speed stirring was performed at 150 rpm for 5 minutes. After separating the whey, the mixture was filled, sealed, and refrigerated.

[0057] [Example 4]

[0058] In this embodiment, the combination of lactic acid bacteria and the fermentation time were adjusted.

[0059] For the experiment, pasteurized milk (100 parts by weight) at 4°C or lower was prepared. After heating to 40°C, a mixed strain (0.05 parts by weight) of Lactobacillus bulgaricus, Lactobacillus casei, and Streptococcus thermophilus was added and fermented for 8 hours. After fermentation, it was cooled to 15°C or lower. Before separating the whey, 12% by weight of deep sea water was added and stirred at 300 rpm for 20 minutes. Subsequently, the whey was separated, and the mixture was filled and sealed.

[0060] [Example 5]

[0061] In this embodiment, low-temperature fermentation was applied.

[0062] For the experiment, pasteurized milk (100 parts by weight) at 4°C was heated to 35°C. A single strain of Lactobacillus acidophilus (0.02 parts by weight) was inoculated and fermented for 10 hours. After fermentation was complete, it was cooled to 10°C. Before separating the whey, 8% by weight of deep sea water was added and stirred at 200 rpm for 15 minutes. After separating the whey, it was filled and refrigerated.

[0063] [Example 6]

[0064] In this embodiment, the timing of deep water injection was adjusted.

[0065] For the experiment, pasteurized milk (100 parts by weight) at 4°C or lower was heated to 40°C. Lactobacillus bulgaricus and Streptococcus thermophilus (0.02 parts by weight) were inoculated, and fermentation was carried out for 5 hours. Immediately after the end of fermentation and before cooling, 5% by weight of deep sea water was added and stirred at 200 rpm for 10 minutes. Afterward, the mixture was cooled to 15°C, and the whey was separated. After filling and sealing, the mixture was refrigerated.

[0066] [Example 7]

[0067] In this embodiment, a mineral concentrate of deep sea water was applied.

[0068] For the experiment, pasteurized milk (100 parts by weight) at 4°C or below was prepared. After heating to 40°C, Lactobacillus helveticus (0.01 parts by weight) was inoculated and fermented for 6 hours. After fermentation, it was cooled to 15°C. Before separating the whey, deep sea water concentrate was added at 3% by weight relative to the total volume and stirred at 200 rpm for 15 minutes. After separating the whey, the mixture was filled, sealed, and refrigerated.

[0069] [Example 8]

[0070] In this example, the solid content was reinforced. For the experiment, 5 parts by weight of skim milk powder were mixed with 95 parts by weight of pasteurized milk at 4°C or lower. After heating to 40°C, a mixed strain of Lactobacillus bulgaricus and Bifidobacterium bifidum (0.05 parts by weight) was inoculated and fermented for 5 hours. After fermentation, it was cooled to 15°C. Before separating the whey, 10% by weight of deep sea water was added and stirred at 250 rpm for 15 minutes. Subsequently, the whey was separated, and the mixture was filled and sealed.

[0071] [Example 9]

[0072] In this embodiment, the fermentation time was shortened.

[0073] For the experiment, 4°C pasteurized milk (100 parts by weight) was prepared. After heating to 45°C, a single strain of Lactobacillus bulgaricus (0.03 parts by weight) was inoculated and fermented for 3 hours. After fermentation, it was cooled to 15°C. Before whey separation, 6% by weight of deep sea water was added and stirred at 200 rpm for 10 minutes. After whey separation, the mixture was filled, sealed, and refrigerated.

[0074] [Example 10]

[0075] In this embodiment, high-concentration deep water conditions were tested.

[0076] For the experiment, 4°C pasteurized milk (90 parts by weight) was prepared. After heating to 40°C, Streptococcus thermophilus and Lactobacillus casei (0.04 parts by weight) were inoculated and fermented for 6 hours. After fermentation, it was cooled to 15°C. Before separating the whey, deep water at 15% by weight of the total weight was added and stirred at 300 rpm for 20 minutes. After separating the whey, it was filled, sealed, and refrigerated.

[0077] [Experimental Example] Evaluation of rancidity and shelf life, and sensory evaluation

[0078] 1. Evaluation of rancidity and best before date

[0079] Storage conditions: Refrigerated at 4℃

[0080] Evaluation Indicators: Peroxide Value (POV), Total Acidity, Microbial Count (Total Bacterial Count)

[0081] Criteria: Considered expired when POV reaches 20 meq / kg and total acidity reaches 1.2%.

[0082] 2. Sensory Evaluation

[0083] Evaluators: 20 adult panelists

[0084] Evaluation criteria: Sweetness, nuttiness, texture (softness), overall preference

[0085] Score: 5-point scale (1 = Very low, 5 = Very high)

[0086] division Expiration date (days) POV (10th) Total acidity (10 days) Preference (5 points) Texture evaluation control group 10 19.8 1.18 3.2 Somewhat rough Example 1 13 15.2 1.05 3.9 Improved Example 2 16 12.8 0.97 4.5 Very soft Example 3 14 13.5 1.01 4.0 Somewhat watery Example 4 15 13.1 0.99 4.4 uniform Example 5 17 11.5 0.95 4.7 Very soft Example 6 14 14.0 1.00 4.1 Improved Example 7 15 13.3 1.02 4.2 flexible Example 8 16 12.9 0.98 4.3 Creamy Example 9 15 13.0 0.97 4.2 uniform Example 10 18 11.0 0.92 4.3 optimal

Claims

Claim 1 A method for manufacturing Greek yogurt using deep sea water, characterized by comprising the steps of: preparing homogenized pasteurized milk stored at 2~6℃; heating the pasteurized milk to a lactic acid bacteria inoculation temperature of 35~45℃; inoculating the pasteurized milk with lactic acid bacteria and fermenting it for 3~10 hours to form a coagulated product; cooling the fermented coagulated product to 10~15℃; adding deep sea water at 5~12% by weight relative to the total mixture to the cooled coagulated product immediately before whey separation and homogenizing by stirring at 150~300 rpm for 5~20 minutes; separating the whey from the deep sea water-treated coagulated product; and filling and sealing the coagulated product from which the whey has been separated. Claim 2 delete Claim 3 A method for producing Greek yogurt using deep sea water, characterized in that, in claim 1, the lactic acid bacteria are Lactobacillus bulgaricus or Streptococcus thermophilus. Claim 4 A method for producing Greek yogurt using deep sea water according to claim 1, characterized in that the lactic acid bacteria further comprise at least one selected from Lactobacillus acidophilus (L. acidophilus), Lactobacillus casei (L. casei), Lactobacillus helveticus (L. helveticus), and Bifidobacterium bifidum. Claim 5 A method for producing Greek yogurt using deep sea water according to claim 1, characterized in that the deep sea water is provided in a concentrated form and added at a ratio of 3 to 5 weight percent. Claim 6 A method for producing Greek yogurt using deep sea water according to claim 1, characterized in that the whey separation is performed by filtration for 30 to 120 minutes or centrifugation at 1,500 to 3,000 × g for 5 to 15 minutes. Claim 7 Greek yogurt using deep sea water prepared according to the method of claim 1.

Images