Processing technology of onion-flavored raw cheese based on ultrasonic treatment and product thereof

Abstract

The application belongs to the technical field of dairy product processing, and provides a processing technology of onion-flavored raw cheese based on ultrasonic treatment, which comprises the following steps: after raw milk is sterilized and cooled, inoculating lactic acid bacteria starter to perform fermentation, then adding rennet to perform curd; cutting the curd and draining whey to obtain curd blocks; adding microencapsulated volatile flavor extract of Chinese chives into the curd blocks and mixing; performing ultrasonic treatment, molding treatment and ripening treatment on the onion-flavored curd blocks. The application realizes stable loading and uniform dispersion of onion-flavored flavoring substances by combining the microencapsulated volatile flavor extract of Chinese chives with the ultrasonic treatment process, reduces the loss of volatile flavoring substances in the processing and ripening process, improves the structural uniformity and moisture distribution state of the curd blocks, improves the molding stability and ripening uniformity, and thus the onion-flavored raw cheese product with stable structure, uniform onion-flavored flavor and good quality consistency is obtained.

Description

Technical Field

[0001] This invention relates to the field of dairy processing technology, and in particular to a processing technology and product of onion-flavored original cheese based on ultrasonic treatment. Background Technology

[0002] Raw cheese is made from cow's milk, sheep's milk, or buffalo milk through processes such as sterilization, lactic acid fermentation, curdling, cutting, whey removal, shaping, and maturation. Compared to processed cheese, its processing relies more heavily on the formation and evolution of the milk protein's own structure. Therefore, the texture, internal structural stability, and controllability of the maturation process place higher demands on the processing technology. However, due to fluctuations in raw milk composition, differences in fermentation behavior, and uneven physical conditions during curdling, the internal structure of the curd often exhibits inhomogeneity. This leads to problems such as uneven moisture distribution, localized loosening or collapse during cutting, whey removal, shaping, and maturation, thus affecting the cheese's texture, shaping stability, and maturation uniformity.

[0003] Existing technologies attempt to improve curd structure by adjusting fermentation temperature, time, and rennet dosage, or by changing cutting size and whey drainage time, but their effects on the internal uniformity of the curd and subsequent maturation stability remain limited. Simply relying on extending maturation time or increasing the precision of maturation condition control can improve the structure to some extent, but it increases the production cycle and energy consumption, which is not conducive to industrial-scale production.

[0004] Onion flavor is widely popular in food due to its unique aroma and high consumer acceptance. However, there are currently no onion-flavored cheese products on the market, making the development of cheese that combines onion flavor with excellent texture and quality a promising application. Existing flavoring methods often borrow from other onion-flavored foods, such as directly adding onion powder, onion oil, or scallion extract. However, due to the complex protein network structure of cheese, volatile flavor compounds are easily volatilized and oxidized, leading to flavor loss during processing and maturation, and making it difficult to achieve uniform flavor across different parts after maturation.

[0005] Therefore, how to achieve a stable loading and uniform distribution of onion flavor substances while maintaining the traditional processing characteristics and structural stability of the original cheese, and at the same time take into account the uniformity of curd structure, molding stability and ripening uniformity, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to address the problems of insufficient uniformity of curd structure, poor molding stability, and limited controllability of the maturation process in the processing of original cheese. At the same time, it solves the technical defects of easy volatilization loss, uneven dispersion, and poor flavor retention of onion flavor substances when applied to cheese systems, and provides a processing technology and product of onion flavor original cheese based on ultrasonic treatment.

[0007] This invention introduces microencapsulated volatile flavor extracts of scallions into curd blocks and combines this with ultrasonic processing. While maintaining the traditional processing characteristics of original cheese, it achieves stable loading and uniform dispersion of scallion flavor substances, reducing the loss of volatile flavor substances during processing and maturation. At the same time, it improves the internal structure of the curd blocks, enhances the stability of the molding process, and facilitates the uniformity of the subsequent maturation process, thereby obtaining a scallion-flavored original cheese product with stable structure, uniform scallion flavor, and good quality consistency.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a processing method for onion-flavored original cheese based on ultrasonic treatment, comprising the following steps: 1) After sterilizing and cooling the raw milk, inoculate it with lactic acid bacteria starter culture for fermentation. After fermentation, add rennet to coagulate the milk and obtain curd. 2) Cut the curd and remove some of the free whey to obtain curd blocks; 3) Add microencapsulated volatile flavor extract of scallions to the curd block and mix well to obtain scallion-flavored curd block; 4) The onion-flavored curd blocks are subjected to ultrasonic treatment, shaping treatment and maturation treatment in sequence to obtain onion-flavored original cheese.

[0009] Preferably, the raw milk in step 1) is one or more of raw cow's milk, raw sheep's milk and raw buffalo milk; The sterilization is pasteurization, with a sterilization temperature of 63~75℃ and a sterilization time of 15~30s; The cooling process involves cooling the raw milk to a temperature of 25-30°C. The lactic acid bacteria starter is Lactococcus lactis and / or Streptococcus thermophilus; the inoculation amount of the lactic acid bacteria starter is 0.02~0.04% of the raw milk mass.

[0010] Preferably, the fermentation temperature in step 1) is 28~35℃, the fermentation time is 60~80min, and the pH value at the end of fermentation is 6.2~6.5.

[0011] Preferably, the rennet in step 1) is animal-derived rennet and / or microbial-derived rennet. The dosage of rennet is 0.003~0.005% of the raw milk mass; The temperature of the curd is 30~35℃, and the curdling time is 30~45min.

[0012] Preferably, step 2) involves cutting the curd into curd blocks with a characteristic size of 1-2 cm. The time for the partial removal of free whey is 20-30 minutes.

[0013] Preferably, the microencapsulated scallion volatile flavor extract in step 3) includes a core material and a wall material; The core material is a volatile flavor extract of scallions; The wall material is one or more of gum arabic, maltodextrin and whey protein; The amount of the microencapsulated volatile flavor extract of scallions added is 0.5-2% of the mass of the curd block.

[0014] Preferably, the power density of the ultrasonic treatment in step 4) is 0.2~0.5W / cm². 2 The frequency of ultrasonic treatment is 20~40kHz, and the duration of ultrasonic treatment is 5~10min.

[0015] Preferably, the molding process in step 4) has a pressure of 0.4~0.6MPa, a temperature of 10~20℃, and a time of 10~15min.

[0016] Preferably, the temperature of the maturation treatment in step 4) is 8~10℃, the relative humidity of the maturation treatment is 85~90%, and the maturation treatment time is 30~40 days.

[0017] The present invention also provides an onion-flavored original cheese prepared by the aforementioned processing technology.

[0018] The beneficial effects of this invention include the following: 1) This invention introduces microencapsulated volatile flavor extracts of scallions, which effectively imparts a distinct and lasting scallion flavor to the original cheese, while reducing the volatilization loss of flavor substances during processing and maturation, thereby improving flavor stability and uniformity.

[0019] 2) This invention improves the structural uniformity and moisture distribution of the curd block through ultrasonic treatment, making the internal structure of the curd block dense, the surface smooth, and the texture delicate, thus avoiding the problems of uneven curd structure, cracks and structural instability in traditional processes.

[0020] 3) The synergistic effect of microencapsulation and ultrasonic treatment in this invention achieves uniform dispersion of flavor substances in the curd block, while ensuring uniform stress during the molding process. The molded cheese blank has a regular shape, intact edges, and no cracks or collapse, thereby improving the molding stability.

[0021] 4) This invention optimizes the initial structure of the pre-mature curd block through ultrasonic treatment and combines it with microencapsulation for flavor protection. During the maturation process, the moisture is redistributed evenly, and the flavor of each part of the cheese is consistent, avoiding local over-maturation or structural collapse, thereby improving the quality of maturation and overall consistency.

[0022] 5) This invention, while maintaining the traditional raw material system and processing characteristics of original cheese, achieves a synergistic effect of flavor preservation and structural optimization through the combination of microencapsulated flavor substances and ultrasonic treatment, avoiding the addition of complex formulas or additional functional components, and preserving the traditional flavor and distinctive taste of original cheese. Detailed Implementation

[0023] This invention provides a processing method for onion-flavored original cheese based on ultrasonic treatment, comprising the following steps: 1) After sterilizing and cooling the raw milk, inoculate it with lactic acid bacteria starter culture for fermentation. After fermentation, add rennet to coagulate the milk and obtain curd. 2) Cut the curd and remove some of the free whey to obtain curd blocks; 3) Add microencapsulated volatile flavor extract of scallions to the curd block and mix well to obtain scallion-flavored curd block; 4) The onion-flavored curd blocks are subjected to ultrasonic treatment, shaping treatment and maturation treatment in sequence to obtain onion-flavored original cheese.

[0024] In this invention, the raw milk in step 1) is preferably one or more of raw cow's milk, raw sheep's milk, and raw buffalo milk; The sterilization is preferably pasteurization; the sterilization temperature is preferably 63~75℃, more preferably 65~70℃, and even more preferably 68℃; the sterilization time is preferably 15~30s, more preferably 20~25s, and even more preferably 22s. The cooling is preferably performed by cooling the raw milk to a temperature of 25-30°C, more preferably by cooling the raw milk to a temperature of 26-28°C, and even more preferably by cooling the raw milk to a temperature of 27°C.

[0025] The lactic acid bacteria starter is preferably Lactococcus lactis and / or Streptococcus thermophilus; the inoculation amount of the lactic acid bacteria starter is preferably 0.02~0.04% of the raw milk mass, more preferably 0.025~0.035%, and even more preferably 0.03%.

[0026] In this invention, the fermentation temperature in step 1) is preferably 28~35℃, more preferably 30~34℃, and even more preferably 32℃; the fermentation time is preferably 60~80min, more preferably 65~75min, and even more preferably 70min; the pH value at the fermentation endpoint is preferably 6.2~6.5, and even more preferably 6.3~6.4.

[0027] In this invention, the rennet in step 1) is preferably animal-derived rennet and / or microbial-derived rennet; The preferred dosage of rennet is 0.003~0.005% of the raw milk mass, and more preferably... 0.0035~0.0045%, more preferably 0.004%; The temperature of the curd is preferably 30~35℃, more preferably 32~34℃, and even more preferably 33℃; the curdling time is preferably 30~45min, more preferably 35~40min, and even more preferably 36~38min.

[0028] In this invention, step 1) involves sterilizing the raw milk, which effectively reduces the number of miscellaneous bacteria, providing a stable microbial environment for subsequent lactic acid bacteria fermentation. Cooling the raw milk to a suitable temperature after sterilization promotes the normal growth and metabolism of the lactic acid bacteria starter culture. Lactic acid bacteria inoculation and fermentation then commence. The agent is fermented to gradually adjust the acidity of the raw milk system to a state suitable for curd formation, which helps to improve the reaction conditions of the milk protein system.

[0029] After fermentation, rennet is added to coagulate the milk, causing casein in the milk to aggregate under enzymatic action and form a curd with a preliminary three-dimensional network structure. By clearly separating the fermentation and coagulation stages, it is beneficial to control the conditional stability of the fermentation and coagulation processes separately, thereby providing a relatively homogeneous curd basis for subsequent process steps.

[0030] In this invention, the cutting in step 2) is preferably cutting the curd into curd blocks with a characteristic size of 1~2cm, more preferably cutting the curd into curd blocks with a characteristic size of 1.4~1.6cm, and more preferably cutting the curd into curd blocks with a characteristic size of 1.5cm. The preferred time for the discharge of a portion of free whey is 20-30 minutes, more preferably 24-26 minutes, and even more preferably 25 minutes.

[0031] In this invention, the discharge of a portion of free whey refers to the discharge of whey that naturally separates after cutting, so that the curd block reaches a state that can be shaped and is suitable for subsequent maturation processing.

[0032] In this invention, step 2), which involves cutting the curd and removing some of the free whey, is an important structural control step in the original cheese-making process. By cutting the curd into curd blocks with a characteristic size of 1-2 cm, a suitable specific surface area can be formed inside the curd blocks, thereby regulating the whey precipitation rate.

[0033] Within this size range, free whey can be effectively removed from the curd, preventing excessive moisture content inside the curd block, while maintaining the overall structural integrity of the curd block to a certain extent, providing a stable physical morphological basis for subsequent ultrasonic processing. By controlling the time for removing some free whey, it is helpful to obtain a curd block with relatively uniform moisture distribution, thereby improving the consistency of subsequent molding and maturation processes.

[0034] In this invention, the microencapsulated scallion volatile flavor extract in step 3) preferably includes a core material and a wall material; The core material is preferably a volatile flavor extract of scallions; The wall material is preferably one or more of gum arabic, maltodextrin, and whey protein; The amount of the microencapsulated scallion volatile flavor extract added is preferably 0.5-2% of the mass of the curd block, more preferably 1-1.5%, and even more preferably 1.2%.

[0035] In this invention, the microencapsulated scallion volatile flavor extract is preferably prepared by the following method: mixing the core material and the wall material to form an emulsion, homogenizing it, and then spray drying it to obtain the microencapsulated scallion volatile flavor extract.

[0036] In this invention, the mass ratio of the core material to the wall material is preferably 1:2 to 6, more preferably 1:3 to 5, and even more preferably 1:4; The pressure of the homogenization process is preferably 20-40 MPa, more preferably 25-35 MPa, and even more preferably 30 MPa. The inlet air temperature of the spray dryer is preferably 140~160℃, more preferably 145~155℃, and even more preferably 150℃; the outlet air temperature of the spray dryer is preferably 70~90℃, more preferably 75~85℃, and even more preferably 80℃.

[0037] In this invention, the preferred method for preparing the volatile flavor extract of scallions includes the following steps: a. Wash fresh scallions and chop them into pieces 0.5-2cm in length, preferably 1-2cm. Add deionized water at a material-to-liquid ratio of 1:2-5, preferably 1:3-4. Mix well and then extract by steam distillation. b. After distillation, the oil-water mixture is collected, and the oil phase is separated after standing and layering to obtain scallion volatile oil; c. After dehydrating the volatile oil of scallions with anhydrous sodium sulfate, the anhydrous sodium sulfate is removed by filtration to obtain the volatile flavor extract of scallions.

[0038] In this invention, the distillation temperature in step a is preferably 95~105℃, more preferably 98~102℃, and even more preferably 100℃; the distillation time is preferably 2~6h, more preferably 3~5h, and even more preferably 4h.

[0039] In this invention, the dehydration treatment time in step c is preferably 12-24 hours, more preferably 15-20 hours, and even more preferably 18 hours.

[0040] In this invention, the power density of the ultrasonic treatment in step 4) is preferably 0.2~0.5W / cm². 2 Further preferably, it is 0.3~0.4 W / cm. 2 More preferably 0.35W / cm 2 The frequency of ultrasonic treatment is preferably 20~40kHz, more preferably 25~35kHz, and even more preferably 30kHz; the duration of ultrasonic treatment is preferably 5~10min, more preferably 6~8min, and even more preferably 7min.

[0041] In this invention, microencapsulated volatile flavor extracts of scallions form stable microparticles by encapsulating volatile oils in scallions, reducing flavor loss during processing and maturation, and improving flavor stability. Ultrasonic treatment generates cavitation and micro-stirring effects during curd processing, ensuring uniform distribution of microcapsules within the curd network and promoting tight arrangement of the curd protein network, thus improving the texture and structural uniformity of the curd. The synergistic effect of microcapsules and ultrasonic treatment guarantees a uniform and lasting scallion flavor, allowing the matured cheese to maintain structural stability while exhibiting a pronounced scallion aroma. This invention achieves a flavorful, texture-uniform, and consistent scallion-flavored cheese through the above mechanisms.

[0042] In this invention, the pressure of the molding process in step 4) is preferably 0.4~0.6MPa, more preferably 0.45~0.55MPa, and even more preferably 0.5MPa; the temperature of the molding process is preferably 10~20℃, more preferably 14~16℃, and even more preferably 15℃; the time of the molding process is preferably 10~15min, more preferably 12~14min, and even more preferably 13min.

[0043] In this invention, after ultrasonic treatment, the onion-flavored curd is molded. By applying appropriate pressure, temperature, and time conditions, the curd is further compacted and forms a stable geometric shape. In the onion-flavored curd after ultrasonic treatment, the microencapsulated volatile flavor extracts of onion can be more uniformly dispersed in the curd network structure, which helps to improve the uniformity of the internal structure and flavor distribution of the curd, thereby improving molding stability and reducing molding defects.

[0044] During the molding process, the gaps between the curd blocks are further reduced under pressure, and the internal structure gradually becomes denser. The microencapsulated volatile flavor extracts of scallions are stably embedded in the curd protein network, providing good initial structural conditions for subsequent maturation and helping to reduce the loss of flavor substances in subsequent processing.

[0045] In this invention, the temperature of the maturation treatment in step 4) is preferably 8~10℃, more preferably 9℃; the relative humidity of the maturation treatment is preferably 85~90%, more preferably 86~88%, and even more preferably 87%; the maturation treatment time is preferably 30~40d, more preferably 34~36d, and even more preferably 35d.

[0046] In this invention, after molding, the shaped cheese blanks are matured under controlled temperature and humidity conditions, causing a series of slow structural changes and biochemical reactions within the onion-flavored original cheese. During the maturation process, moisture is gradually redistributed, and proteins and fats undergo moderate changes under the action of enzymes, contributing to the formation of a stable internal structure and flavor characteristics.

[0047] Meanwhile, the microencapsulated volatile flavor extracts of scallions gradually release their flavor components during the maturation process, allowing the scallion aroma to be distributed more evenly throughout the cheese. Through the synergistic effect of microencapsulation and ultrasonic treatment promoting uniform dispersion, the loss of volatile flavor substances can be reduced, improving the flavor stability and quality consistency of the matured cheese, thus obtaining a pure cheese product with both a stable structure and a distinctive scallion aroma.

[0048] The present invention also provides an onion-flavored original cheese prepared by the aforementioned processing technology.

[0049] In this invention, through the synergistic effect of introducing microencapsulated volatile flavor extracts from scallions, ultrasonic treatment, molding treatment, and maturation treatment, a scallion-flavored original cheese product with uniform flavor, long-lasting flavor, stable internal structure, and consistent quality can be obtained while maintaining the traditional processing characteristics and structural stability of original cheese.

[0050] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0051] The lactococcus used in the following examples and comparative examples is Lactococcus lactis subsp. lactis, and the thermophilic streptococcus is Streptococcus thermophilus. The microencapsulated scallion volatile flavor extract was prepared by the following method: Fresh scallions were washed and chopped to approximately 1 cm in length. Deionized water was added at a material-to-liquid ratio of 1:4, and the mixture was thoroughly mixed. Steam distillation was then performed at 100°C for 4 hours. After distillation, the oil-water mixture was collected, and the oil phase was separated after settling to obtain scallion volatile oil. The obtained scallion volatile oil was dehydrated with anhydrous sodium sulfate for 18 hours, and the anhydrous sodium sulfate was removed by filtration to obtain the volatile flavor extract of scallions.

[0052] A wall material solution was prepared by mixing gum arabic and maltodextrin at a mass ratio of 1:1. The obtained volatile flavor extract of scallions was added to the wall material solution. The mass ratio of core material to wall material was 1:4. After mixing evenly, the mixture was homogenized using a high-pressure homogenizer at a pressure of 30 MPa for 2 times, with each homogenization lasting 10 minutes, to obtain a uniform emulsion.

[0053] The obtained emulsion was dried by spray drying at a pressure of 0.5 MPa, a feed rate of 10 mL / min, an inlet air temperature of 150°C, and an outlet air temperature of 80°C. After drying, the powder was collected to obtain the microencapsulated volatile flavor extract of scallions.

[0054] Example 1: Raw milk was pasteurized at 72°C for 20 seconds. After pasteurization, the raw milk was rapidly cooled to 28°C. Then, *Lactococcus lactis* was inoculated into the cooled raw milk at an inoculum density of 0.03% of the raw milk's mass. After inoculation, fermentation was carried out at 32°C for 70 minutes, with the final pH value reaching 6.3. After fermentation, microbial rennet was added to the fermented milk at an inoculum density of 0.004% of the raw milk's mass, and coagulation was performed at 33°C for 40 minutes to obtain curd.

[0055] The curd was cut into curd blocks with a characteristic size of 1 cm. After cutting, the curd blocks were allowed to stand and some free whey was drained over a period of 25 minutes.

[0056] Microencapsulated volatile flavor extract of scallions was added to the curd block at an amount of 1.2% of the curd block's mass. After mixing evenly, scallion-flavored curd block was obtained.

[0057] Subsequently, the onion-flavored curd block was subjected to ultrasonic treatment at a power density of 0.3 W / cm², a frequency of 25 kHz, and a duration of 8 min. After ultrasonic treatment, the onion-flavored curd block was molded at a temperature of 15℃ and a pressure of 0.5 MPa for 12 min to obtain the molded onion-flavored cheese blank.

[0058] The shaped onion-flavored cheese blanks were placed in an environment with a temperature of 9°C and a relative humidity of 88% for 35 days to mature, thus obtaining the original onion-flavored cheese.

[0059] Example 2: Raw goat milk was pasteurized at a temperature of 63°C for 30 seconds.

[0060] After sterilization, the raw sheep milk was rapidly cooled to 25°C. Then, *Streptococcus thermophilus* was inoculated into the cooled raw sheep milk at an inoculation rate of 0.02% of the raw sheep milk's mass. After inoculation, fermentation was carried out at 28°C for 80 minutes, with the final pH value reaching 6.2. After fermentation, animal-derived rennet was added to the fermented milk at an inoculation rate of 0.003% of the raw sheep milk's mass, and coagulation was performed at 30°C for 45 minutes to obtain curd.

[0061] The curd was cut into curd blocks with a characteristic size of 2 cm. After cutting, the curd blocks were allowed to stand and some free whey was drained over a period of 20 minutes.

[0062] Microencapsulated volatile flavor extract of scallions was added to the curd block at an amount of 0.5% of the curd block's mass. After mixing evenly, scallion-flavored curd block was obtained.

[0063] Subsequently, the onion-flavored curd block was subjected to ultrasonic treatment at a power density of 0.2 W / cm², a frequency of 40 kHz, and a duration of 5 min. After ultrasonic treatment, the onion-flavored curd block was molded at a temperature of 10℃ and a pressure of 0.6 MPa for 10 min to obtain the molded onion-flavored cheese blank.

[0064] The shaped onion-flavored cheese blanks were placed in an environment with a temperature of 8℃ and a relative humidity of 90% for 40 days to mature, thus obtaining the original onion-flavored cheese.

[0065] Example 3: Raw buffalo milk was pasteurized at 75°C for 15 seconds. After pasteurization, the raw buffalo milk was rapidly cooled to 30°C. Then, *Lactococcus lactis* was inoculated into the cooled raw buffalo milk at an inoculation rate of 0.03% of the raw buffalo milk's mass. After inoculation, fermentation was carried out at 35°C for 60 minutes, with the final pH value reaching 6.5. After fermentation, microbial rennet was added to the fermented milk at an inoculation rate of 0.005% of the raw buffalo milk's mass, and coagulation was performed at 35°C for 30 minutes to obtain curd.

[0066] The curd was cut into curd blocks with a characteristic size of 1.5 cm. After cutting, the curd blocks were allowed to stand and some free whey was drained over a period of 30 minutes.

[0067] Microencapsulated volatile flavor extract of scallions was added to the curd block at an amount of 2% of the curd block's mass. After mixing evenly, scallion-flavored curd block was obtained.

[0068] Subsequently, the onion-flavored curd block was subjected to ultrasonic treatment at a power density of 0.5 W / cm², a frequency of 20 kHz, and a time of 10 min. After ultrasonic treatment, the onion-flavored curd block was molded at a temperature of 20℃ and a pressure of 0.4 MPa for 15 min to obtain the molded onion-flavored cheese blank.

[0069] The shaped onion-flavored cheese blanks were placed in an environment with a temperature of 10℃ and a relative humidity of 85% for 30 days to mature, thus obtaining the original onion-flavored cheese.

[0070] Example 4: Raw milk is pasteurized at a temperature of 70°C for 25 seconds.

[0071] After sterilization, the raw milk was rapidly cooled to 26°C. Then, *Streptococcus thermophilus* was inoculated into the cooled raw milk at an inoculation rate of 0.025% of the raw milk's mass. After inoculation, fermentation was carried out at 30°C for 75 minutes, with the final pH value reaching 6.4. After fermentation, animal-derived rennet was added to the fermented milk at an inoculation rate of 0.0035% of the raw milk's mass, and coagulation was performed at 32°C for 45 minutes to obtain curd.

[0072] The curd was cut into curd blocks with a characteristic size of 2 cm. After cutting, the curd blocks were allowed to stand and some free whey was drained. The time for draining free whey was 22 minutes.

[0073] Microencapsulated volatile flavor extract of scallions was added to the curd block at an amount of 1.5% of the curd block's mass. After mixing evenly, scallion-flavored curd block was obtained.

[0074] Subsequently, the onion-flavored curd block was subjected to ultrasonic treatment at a power density of 0.4 W / cm², a frequency of 30 kHz, and a duration of 9 min. After ultrasonic treatment, the onion-flavored curd block was molded at a temperature of 12℃ and a pressure of 0.45 MPa for 13 min to obtain the molded onion-flavored cheese base.

[0075] The shaped onion-flavored cheese blanks were placed in an environment with a temperature of 8℃ and a relative humidity of 86% for 32 days to mature, thus obtaining the original onion-flavored cheese.

[0076] Example 5: Raw goat milk was pasteurized at 74°C for 18 seconds. After pasteurization, the raw goat milk was rapidly cooled to 30°C. Then, *Lactococcus lactis* was inoculated into the cooled raw goat milk at an inoculation rate of 0.035% of the raw goat milk's mass. After inoculation, fermentation was carried out at 34°C for 65 minutes, with the final pH value reaching 6.2. After fermentation, microbial rennet was added to the fermented milk at an inoculation rate of 0.0045% of the raw goat milk's mass, and coagulation was performed at 34°C for 42 minutes to obtain curd.

[0077] The curd was cut into curd blocks with a characteristic size of 2 cm. After cutting, the curd blocks were allowed to stand and some free whey was drained. The time for draining free whey was 26 minutes.

[0078] Microencapsulated volatile flavor extract of scallions was added to the curd block at an amount of 1.8% of the curd block's mass. After mixing evenly, scallion-flavored curd block was obtained.

[0079] Subsequently, the onion-flavored curd block was subjected to ultrasonic treatment at a power density of 0.5 W / cm², a frequency of 35 kHz, and a duration of 7 min. After ultrasonic treatment, the onion-flavored curd block was molded at a temperature of 18℃ and a pressure of 0.55 MPa for 14 min to obtain the molded onion-flavored cheese blank.

[0080] The shaped onion-flavored cheese blanks were placed in an environment with a temperature of 10℃ and a relative humidity of 86% for 38 days to mature, thus obtaining the original onion-flavored cheese.

[0081] Comparative Example 1: Except for the absence of microencapsulated volatile flavor extract of scallions, all other steps were the same as in Example 1.

[0082] Specifically, the raw milk was pasteurized at 72°C for 20 seconds, and then rapidly cooled to 28°C. Lactococcus lactis was inoculated into the cooled raw milk at a rate of 0.03% of the raw milk mass, and fermented at 32°C for 70 minutes until the final pH value was 6.3. After fermentation, microbial rennet was added at a rate of 0.004% of the raw milk mass, and the milk was coagulated at 33°C for 40 minutes to obtain curd.

[0083] The curd was cut into 1cm blocks, left to stand, and some free whey was drained for 25 minutes. The curd blocks were then subjected to ultrasonic treatment, shaping, and maturation to obtain the original cheese.

[0084] Comparative Example 2: Except for the different onion flavoring component added in step 3, the other steps are the same as in Example 1.

[0085] Specifically, after completing the curdling, cutting, and whey removal processes according to Example 1, volatile flavor extracts of scallions (unmicroencapsulated) were directly added to the curd block. The amount added was the same as the mass of the microcapsule core material in Example 1. After mixing evenly, the mixture was subjected to ultrasonic treatment (power density 0.3 W / cm², frequency 25 kHz, time 8 min), molding treatment (temperature 15℃, pressure 0.5 MPa, 12 min), and maturation treatment (temperature 9℃, relative humidity 88%, 35 d) to obtain scallion-flavored original cheese.

[0086] Comparative Example 3: Except for the different onion flavoring component added in step 3, the other steps are the same as in Example 1.

[0087] Specifically, after completing the curdling, cutting, and whey removal processes according to Example 1, volatile flavor extracts of scallions (unmicroencapsulated) were directly added to the curd block. The amount added was the same as the mass of the microcapsule core material in Example 1. After mixing evenly, the mixture was subjected to ultrasonic treatment (power density 0.3 W / cm², frequency 25 kHz, time 8 min), molding treatment (temperature 15℃, pressure 0.5 MPa, 12 min), and maturation treatment (temperature 9℃, relative humidity 88%, 35 d) to obtain scallion-flavored original cheese.

[0088] Comparative Example 4: Except for the different ultrasonic processing parameters, the other steps are the same as in Example 1.

[0089] Specifically, microencapsulated volatile flavor extract of scallions was added to the curd block at an amount of 1.2% of the curd block mass. After mixing evenly, the mixture was subjected to ultrasonic treatment with a power density of 0.05 W / cm², a frequency of 10 kHz, and a time of 15 min. Subsequently, the mixture was subjected to molding treatment (temperature 15°C, pressure 0.5 MPa, 12 min) and maturation treatment (temperature 9°C, relative humidity 88%, 35 d) according to the conditions of Example 1 to obtain scallion-flavored original cheese.

[0090] Comparative Example 5: Except for the different sequence of ultrasonic treatment, all other steps are the same as in Example 1.

[0091] Specifically, after completing the curdling, cutting, and whey removal processes according to Example 1, the cheese blanks are first formed (temperature 15℃, pressure 0.5MPa, 12min) to obtain cheese blanks. Then, the formed cheese blanks are subjected to ultrasonic treatment (power density 0.3W / cm², frequency 25kHz, time 8min), followed by maturation treatment (temperature 9℃, relative humidity 88%, 35d) to obtain onion-flavored original cheese.

[0092] (a) In order to verify the effect of microencapsulated volatile flavor extract of scallions on the formation of scallion flavor, the cheese obtained in Example 1 and Comparative Example 1 (without microencapsulated volatile flavor extract of scallions) were compared and observed.

[0093] The results showed that the cheese obtained in Example 1 had a distinct onion flavor, with a natural and harmonious aroma, and a good blend of milky and onion flavors. In contrast, Comparative Example 1, which did not contain microencapsulated volatile onion flavor extract, only exhibited a milky aroma and did not show a distinct onion flavor. This indicates that microencapsulated volatile onion flavor extract can effectively impart the characteristic onion flavor to the original cheese.

[0094] (ii) In order to verify the effect of microencapsulation on the ability to retain the scallion flavor, Example 1 and Comparative Example 2 (with direct addition of volatile scallion flavor extract, without microencapsulation) were compared and observed.

[0095] The results showed that the scallion flavor in Example 1 remained significantly longer after maturation; while in Comparative Example 2, due to direct addition, some volatile flavor compounds were lost during processing and maturation, resulting in a significant decrease in the intensity of the scallion flavor in the final product. This indicates that microencapsulation can effectively reduce the loss of volatile flavor compounds during processing and maturation, thereby improving flavor retention.

[0096] (III) In order to verify the effect of ultrasonic treatment on improving the uniformity of curd structure and moisture distribution, Example 1 and Comparative Example 3 (microencapsulated volatile flavor extract of scallion added, but without ultrasonic treatment) were compared and observed.

[0097] The results showed that the onion-flavored curd in Example 1 had a uniform structure, consistent moisture distribution, smooth surface, no cracks, and dense interior; while the curd in Comparative Example 3 had a loose structure, uneven moisture distribution, and obvious localized dryness or water accumulation. This indicates that ultrasonic treatment can improve the uniformity of curd structure and moisture distribution, providing good initial conditions for subsequent molding and maturation.

[0098] (iv) In order to verify the effect of ultrasonic treatment on molding stability, the cheese blanks obtained in Example 1 and Comparative Example 3 were compared and observed.

[0099] The results showed that the cheese curd obtained in Example 1 had a regular shape, intact edges, a smooth surface, and a stable overall structure; while the cheese curd obtained in Comparative Example 3 had an uneven surface, with localized cracks or slight collapses. This indicates that ultrasonic treatment helps improve the uniformity of stress on the curd during the molding process, thereby improving molding stability.

[0100] (v) In order to verify the effect of ultrasonic treatment on the ability to maintain structure and the uniformity of ripening during the ripening process, the cheeses obtained in Example 1 and Comparative Example 3 were compared and observed.

[0101] The results showed that the cheese in Example 1 maintained a good overall structure after maturation, with uniform shape in all parts, no obvious collapse or shrinkage, and a uniform flavor distribution; while the cheese in Comparative Example 3 had a loose local structure, poor uniformity of maturation, and uneven flavor distribution. This indicates that ultrasonic treatment can improve the structural stability and flavor uniformity of cheese during the maturation process.

[0102] (vi) In order to verify the effect of microencapsulation and ultrasonic treatment on the uniformity of flavor distribution, the cheeses obtained in Example 1, Comparative Example 2 and Comparative Example 3 were compared and observed.

[0103] The results showed that the cheese obtained in Example 1 had a relatively consistent scallion flavor across all parts, with a uniform flavor distribution. In Comparative Example 2, the flavor was stronger in some areas and weaker in others. Although Comparative Example 3 used microencapsulated volatile scallion flavor extract, the lack of ultrasonic treatment resulted in insufficient uniform dispersion of flavor substances within the cheese. This indicates that the synergistic effect of microencapsulation and ultrasonic treatment helps improve the uniform dispersion of flavor substances in the curd network, thereby enhancing the consistency of product flavor.

[0104] (vii) To verify the effect of ultrasonic treatment parameters on cheese quality, the cheeses obtained in Example 1 and Comparative Example 4 were compared. The results showed that: Example 1, using appropriate ultrasonic treatment parameters, produced cheese with a uniform structure, fine texture, and consistent flavor; while in Comparative Example 4, due to the lower ultrasonic power density and frequency, the ultrasonic treatment effect was weakened, resulting in a decrease in the uniformity of the internal structure and flavor of the cheese. This indicates that ultrasonic treatment parameters have a significant impact on the final product quality, and reasonable ultrasonic treatment conditions can further improve cheese quality.

[0105] (viii) In order to verify the effect of the timing of ultrasonic treatment on the quality of cheese, the cheeses obtained in Example 1 and Comparative Example 5 were compared and observed.

[0106] The results showed that in Example 1, the ultrasonic treatment was performed at the curd stage, resulting in cheese with a uniform structure, stable shaping, and even flavor distribution after maturation. In contrast, in Comparative Example 5, the ultrasonic treatment was performed after shaping, leading to a decrease in both the uniformity of the internal structure and the consistency of the flavor. This indicates that the timing of ultrasonic treatment has a significant impact on cheese quality, and ultrasonic treatment at the curd stage is more conducive to its structural optimization effect.

[0107] In summary, this invention, by combining microencapsulated volatile flavor extracts of scallions with ultrasonic treatment, not only improves the uniformity of curd structure, molding stability, and maturation uniformity, but also enhances the retention and uniformity of scallion flavor, thereby obtaining a scallion-flavored original cheese product with stable structure, uniform scallion flavor, and good quality consistency. Optimizing the timing and parameters of ultrasonic treatment further enhances the quality stability and taste consistency of the cheese, verifying the effectiveness and superiority of the technical solution of this invention.

[0108] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A processing method for onion-flavored original cheese based on ultrasonic treatment, characterized in that, It includes the following steps: 1) After sterilizing and cooling the raw milk, inoculate it with lactic acid bacteria starter culture for fermentation. After fermentation, add rennet to coagulate the milk and obtain curd. 2) Cut the curd and remove some of the free whey to obtain curd blocks; 3) Add microencapsulated volatile flavor extract of scallions to the curd block and mix well to obtain scallion-flavored curd block; 4) The onion-flavored curd blocks are subjected to ultrasonic treatment, shaping treatment and maturation treatment in sequence to obtain onion-flavored original cheese.

2. The processing technology according to claim 1, characterized in that, Step 1) The raw milk is one or more of raw cow's milk, raw sheep's milk, and raw buffalo milk; The sterilization is pasteurization, with a sterilization temperature of 63~75℃ and a sterilization time of 15~30s; The cooling process involves cooling the raw milk to a temperature of 25-30°C. The lactic acid bacteria starter is Lactococcus lactis and / or Streptococcus thermophilus; the inoculation amount of the lactic acid bacteria starter is 0.02~0.04% of the raw milk mass.

3. The processing technology according to claim 2, characterized in that, The fermentation temperature in step 1) is 28~35℃, the fermentation time is 60~80min, and the pH value at the end of fermentation is 6.2~6.

5.

4. The processing technology according to claim 2 or 3, characterized in that, Step 1) The rennet is animal-derived rennet and / or microbial-derived rennet; The dosage of rennet is 0.003~0.005% of the raw milk mass; The temperature of the curd is 30~35℃, and the curdling time is 30~45min.

5. The processing technology according to claim 4, characterized in that, Step 2) The cutting involves cutting the curd into curd blocks with a characteristic size of 1-2 cm; The time for the partial removal of free whey is 20-30 minutes.

6. The processing technology according to claim 5, characterized in that, Step 3) The microencapsulated scallion volatile flavor extract includes a core material and a wall material; The core material is a volatile flavor extract of scallions; The wall material is one or more of gum arabic, maltodextrin and whey protein; The amount of the microencapsulated volatile flavor extract of scallions added is 0.5-2% of the mass of the curd block.

7. The processing technology according to claim 5 or 6, characterized in that, Step 4) The power density of the ultrasonic treatment is 0.2~0.5W / cm². 2 The frequency of ultrasonic treatment is 20~40kHz, and the duration of ultrasonic treatment is 5~10min.

8. The processing technology according to claim 7, characterized in that, Step 4) The molding process involves a pressure of 0.4~0.6MPa, a temperature of 10~20℃, and a time of 10~15min.

9. The processing technology according to claim 8, characterized in that, Step 4) The ripening treatment temperature is 8~10℃, the relative humidity is 85~90%, and the ripening time is 30~40 days.

10. The onion-flavored original cheese prepared by the processing method according to any one of claims 1 to 9.