Preparation method of infant zero-lactose yogurt fermented milk

Abstract

The invention discloses a preparation method of zero-lactose yoghurt fermented milk for infants, which specifically comprises the following steps: firstly, performing high-temperature sterilization on raw milk, then cooling, and adding lactase Nola Fit 5500 before fermentation to perform pre-hydrolysis of lactose so as to ensure zero lactose of the product from the source. Then, compound probiotics composed of bifidobacterium animalis subsp. Lactis HN019, lactobacillus mucus fermentation CECT5716, lactobacillus rhamnosus HN001 and bifidobacterium breve M-16V are added, low-temperature slow fermentation is carried out for 15 hours at the temperature of 41 + / -1 DEG C, and no exogenous sugar is added in the whole process. According to the process, nutritional ingredients are reserved to the maximum extent through mild fermentation, formation of natural flavor is promoted, and the obtained product is safe, nutritional and easy to digest and can effectively improve intestinal health of infants and reduce the risk of digestion discomfort.

Description

Technical Field

[0001] This invention relates to the field of functional dairy products for infants and young children, specifically to a method for producing lactose-free fermented yogurt for infants and young children. Background Technology

[0002] With increasing societal focus on infant and toddler health, functional dairy products have become a market hotspot. Yogurt, rich in protein, calcium, and live probiotics, is considered beneficial for infants' gut health. However, regular yogurt contains lactose, and some infants, due to insufficient lactase activity, are prone to lactose intolerance symptoms such as diarrhea and bloating after consuming it. Current technologies often address this issue by directly adding lactase to regular yogurt or by physical desugaring after fermentation. The former results in incomplete hydrolysis, while the latter can damage nutrients and flavor. Furthermore, to accelerate fermentation and improve taste, commercially available products often add exogenous sugars such as sucrose, which contradicts the concept of a low-sugar diet for infants and toddlers and may increase the risk of tooth decay and the development of undesirable taste preferences. Therefore, developing a truly lactose-free, sugar-free, nutritious, safe, and palatable infant yogurt has significant practical importance and market value. Summary of the Invention

[0003] The present invention aims to solve the above-mentioned technical problems by providing a method for making lactose-free fermented yogurt for infants and young children.

[0004] To solve the above-mentioned technical problems, the technical solution provided by the present invention is: a method for preparing lactose-free fermented yogurt for infants, comprising the following steps: a) Provide raw milk that meets infant food safety standards; b) Sterilize the raw milk at 95℃–98℃ for 300 seconds, and then cool it to 41℃±1℃; c) Add lactase NolaFit5500 to the cooled raw milk and mix thoroughly; d) Add the compound probiotics to the mixture obtained in step c) and stir for 30 minutes to disperse it evenly. The compound probiotics consist of Bifidobacterium animalis subsp. lactis HN019, Lactobacillus fermentum CECT5716, Lactobacillus rhamnosus HN001 and Bifidobacterium breve M-16V. e) The fermentation is carried out at a constant temperature of 41℃±1℃ for a total fermentation time of 15 hours, and no exogenous sugars are added throughout the process. f) When the fermentation acidity reaches the target value, stop the fermentation and cool to obtain the lactose-free fermented yogurt for infants.

[0005] Furthermore, the raw milk in step a) is cow's milk, goat's milk, or reconstituted milk prepared from these sources.

[0006] Furthermore, in step c), the amount of lactase NolaFit5500 added is 1000-5000 neutral lactase units (ALU) per liter of raw milk.

[0007] Furthermore, in step d), the total inoculation amount of the compound probiotics is 1×10⁻⁶. 6 Up to 1×10 8 CFU / mL.

[0008] Furthermore, in the compound probiotics, the ratio of live bacteria of Bifidobacterium animalis subsp. lactis HN019, Lactobacillus fermentum CECT5716, Lactobacillus rhamnosus HN001 and Bifidobacterium breve M-16V is 1:1:1:1.

[0009] Furthermore, during the isothermal fermentation process in step e), after 1 hour of fermentation, a second stirring is performed for 30 minutes to ensure uniform mixing of the cells and the substrate.

[0010] Furthermore, the statement in step e) that no exogenous sugars are added throughout the process means that no sucrose, fructose, glucose, maltose, or honey are added.

[0011] Furthermore, in step f), the acidity of the fermented milk reaches 90°T–110°T when fermentation is terminated.

[0012] Furthermore, the lactose content in the infant lactose-free fermented yogurt obtained in step f) is less than 0.01g / 100g.

[0013] Furthermore, the total number of active probiotics in the lactose-free fermented yogurt obtained in step f) is not less than 1×10⁻⁶. 6 CFU / g.

[0014] The advantages of this invention compared to existing technologies are: by using a pre-fermentation enzymatic hydrolysis process, it achieves true zero lactose, completely solving the problem of lactose intolerance in infants and young children.

[0015] Using a specific blend of probiotics for infants and young children and a low-temperature slow fermentation process, this product is sugar-free throughout the entire process. It not only retains heat-sensitive nutrients such as protein and vitamins to the maximum extent, but also promotes the generation of natural aromatic substances. The product has a delicate texture and pure flavor, which helps infants and young children establish healthy eating habits.

[0016] The synergistic effect of four highly safe bacterial strains gives the product excellent gut health benefits, is more compatible with the digestive systems of infants and young children, and significantly reduces the risk of digestive discomfort. Detailed Implementation

[0017] To make the technical problems, solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] Working principle of the invention: First, high-quality raw milk that meets infant formula standards is selected and subjected to a high-temperature instantaneous sterilization process at 95℃–98℃ for 300 seconds to effectively kill miscellaneous bacteria and harmful microorganisms in the raw milk, while preserving heat-sensitive nutrients to the greatest extent. Then, the sterilized milk is rapidly cooled to a fermentation temperature of 41℃±1℃.

[0019] Before fermentation begins, this invention innovatively adds a specific type of lactase, Nola Fit 5500, to the emulsion and mixes it thoroughly. This step achieves pre-hydrolysis of lactose, breaking down the lactose in the raw milk into galactose and glucose before fermentation, thereby ensuring that the lactose content in the final product is below the detection limit, solving the problem of lactose intolerance in infants at its source. The hydrolyzed monosaccharides also provide a more readily available energy source for the subsequent growth of probiotics.

[0020] Next, a carefully selected probiotic blend was added to the emulsion. This blend consisted of *Bifidobacterium animalis* subsp. *lactospirum* HN019, *Lactobacillus fermentum* CECT5716, *Lactobacillus rhamnosus* HN001, and *Bifidobacterium breve* M-16V. After adding the bacteria, the mixture was stirred for 30 minutes to ensure that the bacteria were evenly dispersed in the emulsion, laying the foundation for subsequent uniform fermentation.

[0021] This invention employs a low-temperature slow fermentation process at 41℃±1℃, with a total fermentation time of up to 15 hours, and no exogenous sugars are added throughout the process. Because the selected probiotic combination has relatively mild metabolic activity and a low acid production rate, extending the fermentation time is crucial for its full metabolism and the formation of ideal texture and flavor. One hour after fermentation begins, a second stirring for 30 minutes is performed. This helps release the metabolic gases produced in the early stages of fermentation and promotes renewed uniform contact between the bacteria and the nutrient substrate, optimizing the overall fermentation environment. The acidity changes throughout the fermentation process exhibit a typical three-stage characteristic: a lag phase, a logarithmic growth phase, and a stationary phase. Fermentation is terminated once the target acidity is reached, and the finished product is obtained after cooling.

[0022] Example 1: First, high-quality raw milk that has been tested and meets national infant food safety standards is selected as the raw milk. The raw milk is preheated to 65°C using a plate heat exchanger, and then pumped into an ultra-high temperature instantaneous sterilization device, where it is sterilized at 95°C for 300 seconds. The purpose of this step is to thoroughly kill any pathogenic bacteria and other microorganisms that may be present in the raw milk, ensuring the purity of subsequent fermentation and the safety of the product. After sterilization, the milk is rapidly cooled to 41°C.

[0023] Next, the sterilized emulsion, cooled to 41°C, is transferred to a sterile fermentation tank. Before fermentation begins, lactase Nola Fit 5500 is added to the emulsion at a rate of 3000 neutral lactase units per liter of emulsion. The agitator is turned on and stirred at low speed for 15 minutes to ensure that the lactase is completely dissolved and evenly distributed in the emulsion.

[0024] Next, prepare the probiotic suspension. This probiotic suspension is composed of *Bifidobacterium animalis* subsp. *lactobacter* HN019, *Lactobacillus fermentum* CECT5716, *Lactobacillus rhamnosus* HN001, and *Bifidobacterium breve* M-16V lyophilized powder in a 1:1:1:1 live bacteria ratio. The mixed bacterial powder is dissolved and activated with a small amount of sterile physiological saline, and then inoculated into the fermentation tank to achieve a total inoculum of 5 × 10⁻⁶ probiotics in the emulsion. 7 CFU / mL. After inoculation, continue stirring for 30 minutes to ensure even dispersion of the bacteria.

[0025] Subsequently, the feed inlet of the fermenter was closed, and constant temperature fermentation was carried out at 41°C for a total fermentation time of 15 hours. One hour after fermentation started, the stirring device was turned on for a second stirring for 30 minutes to ensure that the cells and nutrient substrate remained highly uniform.

[0026] Finally, fermentation was immediately terminated when the online acidity meter showed that the acidity of the fermented milk reached 100°T. Cooling water was then introduced into the jacket of the fermentation tank to rapidly lower the temperature of the fermented milk to 4°C-10°C. The cooled yogurt was then packaged in a sterile environment and subsequently aged for 24 hours in a cold storage at 2°C-6°C. The final lactose-free fermented yogurt for infants was tested and found to have a lactose content of less than 0.01g / 100g and a total number of active probiotics of not less than 1×10⁻⁶. 8 CFU / g.

[0027] Example 2 The manufacturing method of this embodiment is basically the same as that of Embodiment 1, except that: The raw milk is made from high-quality whole goat milk powder that meets infant food safety standards, reconstituted with purified water at a ratio of 1:7. The sterilization temperature is 96℃, followed by cooling to 42℃. The dosage of lactase Nola Fit 5500 is 1000 neutral lactase units per liter of milk. The total inoculum size of the compound probiotics is 1×10⁻⁶. 6 CFU / mL. Fermentation temperature: 42°C. Fermentation is terminated when the acidity of the fermented milk reaches 90°T. The resulting product has the mild flavor characteristic of goat milk and a softer texture.

[0028] Example 3 The manufacturing method of this embodiment is basically the same as that of Embodiment 1, except that: The sterilization temperature is 98℃, followed by cooling to 40℃. The dosage of lactase Nola Fit 5500 is 5000 neutral lactase units per liter of emulsion. The total inoculum size for the compound probiotics is 1×10⁻⁶. 8 CFU / mL. Fermentation temperature: 40℃. Fermentation is terminated when the acidity of the fermented milk reaches 110°T. The resulting product has relatively high acidity, a richer flavor, and a higher content of active probiotics.

[0029] The present invention and its embodiments have been described above. This description is not restrictive, and the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and, without departing from the spirit of the invention, design similar structures and embodiments without creative effort, all such designs should fall within the protection scope of the present invention.

Claims

1. A method for preparing lactose-free fermented yogurt for infants and young children, characterized in that: Includes the following steps: a) Provide raw milk that meets infant food safety standards; b) Sterilize the raw milk at 95℃–98℃ for 300 seconds, and then cool it to 41℃±1℃; c) Add lactase NolaFit5500 to the cooled raw milk and mix thoroughly; d) Add the compound probiotics to the mixture obtained in step c) and stir for 30 minutes to disperse it evenly. The compound probiotics consist of Bifidobacterium animalis subsp. lactis HN019, Lactobacillus fermentum CECT5716, Lactobacillus rhamnosus HN001 and Bifidobacterium breve M-16V. e) The fermentation is carried out at a constant temperature of 41℃±1℃ for a total fermentation time of 15 hours, and no exogenous sugars are added throughout the process. f) When the fermentation acidity reaches the target value, stop the fermentation and cool to obtain the lactose-free fermented yogurt for infants.

2. The method for preparing lactose-free fermented yogurt for infants according to claim 1, characterized in that: The raw milk in step a) is cow's milk, goat's milk, or reconstituted milk prepared from them.

3. The method for preparing lactose-free fermented yogurt for infants according to claim 1, characterized in that, In step c), the amount of lactase NolaFit5500 added is 1000-5000 neutral lactase units (ALU) per liter of raw milk.

4. The method for preparing lactose-free fermented yogurt for infants according to claim 1, characterized in that, In step d), the total inoculation amount of the compound probiotics is 1×10⁻⁶. 6 Up to 1×10 8 CFU / mL.

5. A method for preparing lactose-free fermented yogurt for infants according to any one of claims 1 or 4, characterized in that, The ratio of live bacteria in the compound probiotics is 1:1:1:

1.

6. The method for preparing lactose-free fermented yogurt for infants according to claim 1, characterized in that, During the constant temperature fermentation process in step e), after 1 hour of fermentation, a second stirring is performed for 30 minutes to ensure uniform mixing of the cells and the substrate.

7. The method for preparing lactose-free fermented yogurt for infants according to claim 1, characterized in that, The statement in step e) that no exogenous sugars are added throughout the process means that no sucrose, fructose, glucose, maltose, or honey are added.

8. The method for preparing lactose-free fermented yogurt for infants according to claim 1, characterized in that, In step f), the acidity of the fermented milk reaches 90°T–110°T when fermentation is terminated.

9. A method for preparing lactose-free fermented yogurt for infants according to claim 1, characterized in that, The lactose content in the infant lactose-free fermented yogurt obtained in step f) is less than 0.01g / 100g.

10. A method for preparing lactose-free fermented yogurt for infants according to claim 1, characterized in that, The lactose-free fermented yogurt for infants obtained in step f) has a total number of active probiotics of not less than 1×10⁻⁶. 6 CFU / g.