Wheat germ goat milk cheese and preparation method thereof

Abstract

The invention discloses wheat germ goat milk cheese and a preparation method thereof, and belongs to the technical field of cheese processing. Wheat germ powder and goat milk are used as raw materials to prepare the wheat germ goat milk cheese, the stability of wheat germs is kept through high-temperature baking, the wheat germ goat milk cheese is added into goat milk, and a goat milk cheese product which is rich in wheat fragrance, fine and smooth in taste, unique in flavor and rich in nutrition is developed. The wheat germ goat milk cheese product disclosed by the invention has an excellent anti-oxidation characteristic, the content of butyric acid, hexanoic acid, octanoic acid and other acid substances related to goat milk smell in the product is obviously reduced, and the wheat germ goat milk cheese product has a flavor characteristic easily accepted by consumers.

Description

Technical Field

[0001] The invention belongs to the technical field of cheese processing and relates to wheat germ goat milk cheese and a preparation method thereof. Background Art

[0002] Goat milk is a nutritious natural food, containing a variety of nutrients that are beneficial to human health. Goat milk is rich in protein, including casein and whey protein. These proteins are easy to digest and absorb, and can provide a high-quality protein source for the human body; the fat content of goat milk is moderate, and long-term drinking will not cause weight gain. The fat globule volume of goat milk is significantly smaller than that of cow milk, and it is easier to be absorbed by the human body; goat milk is rich in a variety of minerals and vitamins, and has significant advantages in maintaining vision, promoting human development, mineral element absorption, lowering cholesterol, and improving immunity. Cheese, also known as cheese, is a dairy product made from fresh milk, cream, partially skimmed milk, buttermilk or their mixtures, which is made by coagulating and separating whey. It is rich in protein, polypeptides, fat, vitamins and minerals. It is a concentrated dairy product and is known as the "gold of milk". Goat milk cheese has a delicate taste and unique flavor and nutritional value. However, cheese made from goat milk is prone to produce a strong smell, resulting in low consumer acceptance.

[0003] Wheat germ is a byproduct of wheat flour milling process, accounting for about 2.5% to 3.5% of whole wheat. It has high nutritional value and is rich in various nutrients such as protein, vitamins, minerals, and various bioactive ingredients, such as sterols, tocopherols, tocotrienols, phenols, and carotenoids. As a byproduct of wheat flour milling, wheat germ is currently mainly discarded or sold cheaply as feed, lacking high value-added utilization forms. The prior art mostly adds fruits and vegetables and their products into goat cheese, and there is no report on goat cheese products combining goat cheese and wheat germ. Therefore, it is of great significance to provide a cheese preparation method combining goat cheese and wheat germ to better reduce the mutton smell of cheese products. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a wheat germ goat cheese and a preparation method thereof. The present invention uses wheat germ powder and goat milk as raw materials to prepare wheat germ goat cheese, uses high-temperature baking to maintain the stability of wheat germ, and adds it to goat milk to develop a goat cheese product with rich wheat aroma, delicate taste, unique flavor and rich nutrition. The content of acidic substances such as butyric acid, caproic acid and octanoic acid related to the mutton smell of goat milk in the wheat germ goat cheese of the present invention is significantly reduced, and has flavor characteristics that are easy for consumers to accept. The wheat germ goat cheese product of the present invention has excellent antioxidant properties, and the DPPH free radical scavenging rate is significantly higher than that of other samples.

[0005] To achieve the technical purpose of the present invention, on the one hand, the present invention provides a method for preparing wheat germ goat cheese, which specifically comprises the following steps:

[0006] S1: Spread the raw wheat germ on tin foil with a thickness of 0.5-1.5 cm, bake in an oven at 150-190°C for 10-20 min, then cool to room temperature, grind with a grinder, pass through a 50-mesh sieve, and remove larger particles to obtain wheat germ powder.

[0007] S2: adding wheat germ powder to raw goat milk in a ratio of 0 to 6.0 wt %; heating and sterilizing at 60 to 75° C. for 15 to 45 min to obtain mixed raw milk.

[0008] S3: The mixed raw milk of S2 is quickly cooled to 35-45°C, and the amount of lactic acid bacteria starter added is 1.0-5.0 g / L (based on the volume of raw goat milk). After adding the starter, stirring is continued for 5 minutes to completely dissolve the bacterial powder, and the temperature is maintained at 36-44°C. Fermentation is carried out at a constant temperature until the pH is 6.3-5.3 to obtain fermented mixed milk.

[0009] S4: Add a 15% (w / v) calcium chloride solution to the fermented mixed milk and stir evenly, the amount of calcium chloride solution added is 2.0 g / L (based on the volume of raw goat milk), add rennet, the amount of rennet added is 0.2-1.0 g / L (based on the volume of raw goat milk), dilute the rennet with chlorine-free water (1:100) before adding, and stir during the addition process to make it evenly dispersed, and let it stand for 20-50 minutes to obtain curd.

[0010] S5: Cut the curd into cubes with a side length of 0.5 to 4.5 cm, let it stand to separate the whey, and filter it with four layers of gauze when the end point pH is 5.2 to 4.3 to drain the whey and obtain curd.

[0011] S6: Wrap the curd with gauze and put it into a mold to press for 4 hours to form it, then cut it into 3 cm×2 cm×1.5 cm rectangular blocks to allow it to be fully soaked in saline, soak it in sterilized 2-5 wt% saline at 4°C for 20-50 minutes, drain the surface water, and obtain wheat germ goat cheese.

[0012] Preferably, the raw wheat germ in S1 is spread to a thickness of 1 cm and baked in an oven at 180° C. for 15 min.

[0013] Preferably, the proportion of wheat germ powder added to the raw goat milk in S2 is 3.0-6.0wt%; further preferably, the proportion of wheat germ powder added to the raw goat milk in S2 is 4.5wt%.

[0014] Furthermore, wheat germ powder is added in small amounts and multiple times in S2 while being stirred to prevent the wheat germ powder from agglomerating during the adding process, thereby affecting the quality of the finished wheat germ goat cheese.

[0015] Preferably, the sterilization is carried out by heating at 63-65° C. for 30 min in S2.

[0016] Preferably, in S3, the mixed raw milk of S2 is rapidly cooled to 38°C.

[0017] Preferably, the amount of lactic acid bacteria starter added in S3 is 2.0 g / L.

[0018] Furthermore, the lactic acid bacteria fermentation agent is a lactic acid bacteria yogurt fermentation powder of 5 bacteria type, consisting of Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus casei. Other lactic acid bacteria fermentation preparations with acidification ability can also be selected.

[0019] Preferably, the temperature in S3 is maintained at 38° C. and the fermentation is performed at a constant temperature until the pH value is 6.0 to 5.6; more preferably, the fermentation is performed until the pH value is 5.8.

[0020] Furthermore, after adding the calcium chloride solution in S4, stirring is performed evenly to ensure that the structure of the clot formed after adding rennet is uniform.

[0021] Preferably, the amount of rennet added in S4 is 0.4-0.8 g / L; more preferably, the amount of rennet added in S4 is 0.6 g / L.

[0022] Preferably, the curd is obtained by standing for 30 minutes in S4, and the curd is cut into cubes with a side length of 1.5 cm in S5.

[0023] Preferably, when the end point pH in S5 is 5.0-4.6, it is filtered through four layers of gauze; further preferably, when the end point pH in S5 is 4.8, it is filtered through four layers of gauze.

[0024] Preferably, in S6, the sample is immersed in sterilized 3.5 wt % saline for 40 min.

[0025] In addition, the present invention claims a wheat germ goat cheese, which is prepared by the above-mentioned preparation method of wheat germ goat cheese.

[0026] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0027] (1) The present invention combines wheat germ powder with goat milk to prepare wheat germ goat cheese, and optimizes the processing technology of wheat germ goat cheese through single factor and orthogonal test, so that the finished wheat germ goat cheese has fine texture, rich wheat aroma, unique flavor, attractive color, simple ingredients, rich nutrition, and does not contain food additives, which meets people's needs for healthy diet. The overall flavor of the wheat germ goat cheese product is soft, which effectively weakens the mutton smell in goat cheese. The content of acid substances such as butyric acid, caproic acid and octanoic acid related to the mutton smell of goat milk in the wheat germ goat cheese is significantly reduced, and it has flavor characteristics that are easy for consumers to accept. The wheat germ goat cheese product of the present invention has excellent antioxidant properties, and the DPPH free radical scavenging rate is significantly higher than that of other samples.

[0028] (2) The wheat germ goat cheese provided by the present invention has the advantages of not requiring complex processing equipment, simple preparation method, high product production efficiency and yield, low fat content, good flavor and taste, and good antioxidant effect. The wheat germ goat cheese prepared by the present invention has high moisture content, soft texture, smooth and delicate texture, low fat content, and appropriate acidity. The fat content of the wheat germ goat cheese of the present invention is reduced from about 25% of goat cheese to about 11%, which meets the demand of consumers who tend to consume foods with low fat content. The present invention can save processing time and improve the yield of finished products after adding baked cooked wheat germ powder. The processing time of the wheat germ goat cheese of the present invention is reduced from about 397min of goat cheese to about 300min, and the yield of wheat germ goat cheese is increased from about 10% of goat cheese to about 18%, thereby improving the economic benefits of the product.

[0029] (3) Wheat germ is rich in various nutrients such as protein, vitamins, minerals, and also contains various biologically active ingredients, but its high enzyme activity and high unsaturated fatty acid content cause the fat to easily become rancid. The present invention bakes the wheat germ at high temperature and then grinds it into powder. The baking process improves the stability and quality of the wheat germ, eliminates the wheat smell in the raw wheat germ, promotes the formation of fragrance in the wheat germ, and adds the wheat germ powder to goat milk to prepare cheese. This treatment solves the problem of large wheat germ particles directly added to goat milk cheese, resulting in a rough taste. The present invention provides a specific process method for high value-added utilization of wheat germ, a by-product of the wheat flour industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention.

[0031] Figure 1 This is a graph showing the effect of different wheat germ powder addition amounts on the sensory score of wheat germ goat cheese.

[0032] Figure 2 This is a graph showing the effect of different lactic acid bacteria starter addition amounts on the sensory score of wheat germ goat cheese.

[0033] Figure 3 This is a graph showing the effect of different fermented mixed milk pH endpoints on the sensory score of wheat germ goat cheese.

[0034] Figure 4 This is a graph showing the effect of different rennet addition amounts on the sensory scores of wheat germ goat cheese.

[0035] Figure 5 This is a graph showing the effect of different whey discharge endpoint pH on the sensory score of wheat germ goat cheese.

[0036] Figure 6 This is the finished product of wheat germ goat cheese prepared under the optimal process. Figure 6 A in the figure is a top view; Figure 6 B in the figure is the main view.

[0037] Figure 7 The electronic tongue analysis results of four cheese samples are shown in Figure 2.

[0038] Figure 8 The volatile flavor compound content of four cheese samples is shown in Figure 2.

[0039] Fig. 9 This is the finished product of the goat cheese prepared in comparative experiment 1.

[0040] Fig.10 This is the finished product of wheat germ goat cheese prepared in comparative experiment 2. Fig.10 A in the figure is a top view; Fig.10 B in the figure is the main view.

[0041] Fig.11 This is the finished product of wheat germ goat cheese prepared in comparative experiment 3. Fig.11 A in the figure is a top view; Fig.11 B in the figure is the main view.

[0042] Fig.12 This is a diagram showing the sensory evaluation results of the cheese products prepared in Experiments 1 to 2 and Comparative Experiments 1 to 3. DETAILED DESCRIPTION

[0043] The technical scheme of the present invention is described below in conjunction with the embodiments, but the present invention is not limited to the following embodiments. The experimental methods and detection methods described in each embodiment are conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

[0044] Raw wheat germ was purchased from an edible agricultural product farm in Zaozhuang City, Shandong Province.

[0045] Raw goat milk was purchased from the breeding farm of Northwest Agriculture and Forestry University.

[0046] The lactic acid bacteria starter was a 5-bacteria type of lactic acid bacteria yogurt starter powder, consisting of Lactobacillus bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus casei, purchased from Beijing Chuanxiu Technology Co., Ltd.

[0047] Calcium chloride was food grade and purchased from Jiangsu Ruikanglai Technology Co., Ltd.

[0048] Rennet solution was purchased from Hebei Homeopathic Biotechnology Co., Ltd.

[0049] Example 1

[0050] This example provides a single factor experiment for wheat germ goat cheese production.

[0051] The preparation method of wheat germ goat milk cheese comprises the following steps:

[0052] S1: Spread the raw wheat germ on tin foil with a thickness of 1 cm, bake in an oven at 180°C for 15 minutes, then cool to room temperature, grind with a grinder, pass through a 50-mesh sieve, and remove larger particles to obtain wheat germ powder.

[0053] S2: adding wheat germ powder in small amounts to raw goat milk multiple times while stirring, wherein the ratio of wheat germ powder added to raw goat milk is 3.0 wt %, and heating and sterilizing the raw milk at 63° C. for 30 min to obtain mixed raw milk.

[0054] S3: The mixed raw milk of S2 is quickly cooled to 38°C, and the amount of lactic acid bacteria starter added is 2.0 g / L. After adding the lactic acid bacteria starter, stirring is continued for 5 minutes to completely dissolve the bacterial powder, and the temperature is maintained at 38°C and fermented to a pH of 6.0 to obtain fermented mixed milk.

[0055] S4: Add a 15% (w / v) calcium chloride solution to the fermented mixed milk in an amount of 2.0 g / L (based on the volume of raw goat milk), and stir evenly, add rennet in an amount of 0.4 g / L (based on the volume of raw goat milk), dilute the rennet with chlorine-free water (1:100) before adding, and stir during the addition process to make it evenly dispersed, and let it stand for 30 minutes to obtain curd.

[0056] S5: Cut the curd into cubes with a side length of about 1.5 cm, let it stand to separate the whey, and filter it with four layers of gauze when the end point pH is 4.8 to drain the whey and obtain curd.

[0057] S6: Wrap the curd with gauze and put it into a mold to press for 4 hours to form it, then cut it into 3 cm×2 cm×1.5 cm cuboids, soak it in sterilized 3.5 wt% saline at 4°C for 40 minutes, drain the surface water, and obtain wheat germ goat cheese.

[0058] 20 volunteers were selected to evaluate the prepared wheat germ goat cheese using the wheat germ goat cheese sensory evaluation table (Table 1).

[0059] Table 1 Sensory evaluation table of wheat germ goat cheese

[0060]

[0061] 1. Single factor test of wheat germ powder addition amount. The proportions of wheat germ powder added in S2 were 0wt%, 1.5wt%, 3.0wt%, 4.5wt%, and 6.0wt%, respectively. Three parallel groups were set for each gradient. 20 volunteers were selected to evaluate the prepared wheat germ goat cheese using the wheat germ goat cheese sensory evaluation table. The sensory evaluation results are as follows: Figure 1 shown.

[0062] Depend on Figure 1 It can be seen that when the addition amount of wheat germ powder is in the range of 0-6.0wt%, the sensory score of the prepared wheat germ goat cheese shows a trend of first increasing and then decreasing with the increase of the addition amount of wheat germ powder. When the addition amount is 4.5%, the wheat germ goat cheese has a moderate brown-yellow color, a coordinated and rich wheat flavor and milk flavor, a moderate sour taste, and a moderate hardness and softness. At this time, the sensory score is the highest, and subsequent orthogonal experiments are carried out in combination with 3.0wt% and 6.0wt%.

[0063] 2. Single factor test of the amount of lactic acid bacteria starter added. The amount of lactic acid bacteria starter added in S3 was 1.0 g / L, 2.0 g / L, 3.0 g / L, 4.0 g / L, and 5.0 g / L, respectively. Three parallel groups were set for each gradient. 20 volunteers were selected to evaluate the prepared wheat germ goat cheese using the wheat germ goat cheese sensory evaluation table. The sensory evaluation results are as follows: Figure 2 shown.

[0064] Depend on Figure 2 It can be seen that when the addition amount of lactic acid bacteria starter is in the range of 1.0-5.0 g / L, there is no significant difference in the sensory score of the prepared wheat germ goat cheese. Considering the time cost and raw material cost, the addition amount of lactic acid bacteria starter is 2.0 g / L selected for subsequent experiments.

[0065] 3. Single factor test of pH endpoint of fermented mixed milk. In S3, the constant temperature of 38°C was maintained and the pH was fermented to 6.2, 6.0, 5.8, 5.6, and 5.4, respectively. Three parallel groups were set for each gradient. 20 volunteers were selected to evaluate the prepared wheat germ goat cheese using the wheat germ goat cheese sensory evaluation table. The sensory evaluation results are as follows: Figure 3 shown.

[0066] Depend on Figure 3 It can be seen that when the pH endpoint of the fermented mixed milk is in the range of 6.2-5.4, the sensory score of the prepared wheat germ goat cheese shows a trend of first increasing and then leveling off. When the pH endpoint is 6.0, the sensory score is maintained at a high level. Under this condition, the color of the wheat germ goat cheese is uniform, and there is no significant difference in the subsequent sensory score. The fermented mixed milk pH is selected to lower the endpoint of 6.0 for subsequent experiments.

[0067] 4. Single factor test of rennet addition amount. The addition amount of rennet in S4 was 0.2 g / L, 0.4 g / L, 0.6 g / L, 0.8 g / L and 1.0 g / L respectively. Three parallel groups were set for each gradient. 20 volunteers were selected to evaluate the prepared wheat germ goat cheese using the wheat germ goat cheese sensory evaluation table. The sensory evaluation results are as follows: Figure 4 shown.

[0068] Depend on Figure 4 It can be seen that in the range of 0.2-1.0 g / L of rennet addition, the sensory score of the prepared wheat germ goat cheese showed a trend of first increasing and then decreasing. When the rennet addition amount was 0.6 g / L, the wheat germ goat cheese had uniform color, rich and harmonious taste without bitterness, and was smooth and delicate. At this time, the sensory score was the highest. Subsequent orthogonal experiments were carried out in combination with rennet addition amounts of 0.4 g / L and 0.8 g / L.

[0069] 5. Single factor test of whey end point pH. The end point pH in S5 was 5.2, 5.0, 4.8, 4.6, and 4.4, respectively. Three parallel groups were set for each gradient. 20 volunteers were selected to evaluate the prepared wheat germ goat cheese using the wheat germ goat cheese sensory evaluation table. The sensory evaluation results are as follows: Figure 5 shown.

[0070] Depend on Figure 5 It can be seen that the sensory score shows a trend of first increasing and then decreasing in the range of pH 5.2-4.4 at the end point of whey drainage. When the pH of the end point of whey drainage is 4.8, the wheat germ goat cheese has a brown color, moderate sourness, and a coordinated and rich wheat germ aroma and milk aroma. At this time, the sensory score is the highest. Subsequent orthogonal experiments were carried out in combination with the pH of 5.0 and 4.6 at the end point of whey drainage.

[0071] Example 2

[0072] This example provides an orthogonal experiment for the preparation of wheat germ goat cheese.

[0073] The preparation method of wheat germ goat cheese is the same as that of Example 1. The sample yield and titratable acidity are determined, and sensory evaluation is performed according to Table 1, and the total score is calculated: total score = sample yield (%) × 20% + titratable acidity × 20% + sensory evaluation × 60%. The orthogonal test design factors and levels are shown in Table 2, the orthogonal test results are shown in Table 3, and the range analysis results of the orthogonal test are shown in Table 4.

[0074] Table 2 Orthogonal experimental design factors and levels

[0075]

[0076] Table 3 Orthogonal test results

[0077]

[0078]

[0079] Table 4 Range analysis results of orthogonal test

[0080]

[0081] As shown in Table 4, the range analysis found that the primary and secondary factors affecting the total score were A>C>B, that is, the amount of wheat germ powder added had the greatest impact, followed by the pH at the end of whey drainage, and the amount of rennet added had the least impact. The optimal combination was A2C2B2, that is, when the amount of wheat germ powder added was 4.5%, the amount of rennet added was 0.6g / L, and the pH at the end of whey drainage was 4.8, the wheat germ goat cheese obtained had the best comprehensive score.

[0082] The finished product of wheat germ goat cheese is Figure 6 As shown, under the optimal combination conditions, the sensory score of wheat germ goat cheese was 85.10±2.33 points, the yield was 18.32±0.29%, the titratable acidity was 77.99±5.83°T, and the total score was 70.32, which was in line with the expected results. Therefore, the optimal process was determined to be A2C2B2.

[0083] Example 3

[0084] This example provides quality analysis of wheat germ goat cheese.

[0085] 1. Analysis of nutrient content

[0086] The samples are wheat germ goat cheese prepared under the optimal process conditions in the orthogonal test, goat cheese prepared without adding wheat germ powder in S2, commercial goat cheese product 1 (Qilesa original goat cheese), and commercial goat cheese product 2 (Belas goat salad cheese). The nutritional components, pH, chewiness, total process time, and yield of the samples are analyzed, and the results are shown in Table 5. As shown in Table 5, the wheat germ goat cheese prepared by the present invention has high moisture content, soft texture, smooth and delicate texture, low fat content, and appropriate acidity, and is easily accepted by consumers. The fat content of the wheat germ goat cheese of the present invention is reduced from about 25% of goat cheese to about 11%. The present invention can save processing time and improve the yield of finished products after adding baked cooked wheat germ powder. The processing time of the wheat germ goat cheese of the present invention is reduced from about 397min of goat cheese to about 300min, and the yield of wheat germ goat cheese is increased from about 10% of goat cheese to about 18%.

[0087] Table 5 Analysis of nutritional content of wheat germ goat cheese

[0088]

[0089] 2. Electronic tongue analysis

[0090] The samples were wheat germ goat cheese prepared under the optimal process conditions in the orthogonal test, goat cheese prepared without wheat germ powder in S2, commercial goat cheese product 1, and commercial goat cheese product 2. 5 g of sample was weighed and added to 100 mL of pure water. After homogenization and thorough mixing, the mixture was centrifuged at 5000 rpm for 20 min. After removing the upper fat layer, the supernatant was filtered and poured into a special beaker for electronic tongue. The taste analysis system (SA402B, Insent, Japan) was used for detection. The reference solution was prepared with potassium chloride and tartaric acid. Each sample was tested in parallel 3 times. The radar chart of the electronic tongue analysis results is shown in the figure below. Figure 7 shown.

[0091] Depend on Figure 7 It can be seen that the electronic tongue analysis results of the four samples are significantly different. The wheat germ goat cheese has moderate sourness, lower bitterness, astringency, bitter aftertaste and saltiness than the commercial goat cheese products, and the overall flavor is soft. The astringency aftertaste is lower than the commercial goat cheese product 2, but higher than goat cheese and commercial goat cheese product 1. The umami taste is lower than the commercial goat cheese product 2, but higher than goat cheese and commercial goat cheese product 1. The richness is lower than goat cheese, but higher than the two commercial goat cheese products.

[0092] 3. Analysis of flavor substances and their contents

[0093] The samples were wheat germ goat cheese prepared under the optimal process conditions in the orthogonal experiment, goat cheese prepared without wheat germ powder in S2, commercial goat cheese product 1, and commercial goat cheese product 2. The types and contents of volatile compounds in the four samples were analyzed by GC-MS. 5g of sample was weighed, and the internal standard was 2-octanol methanol solution with a mass concentration of 10mg / L. Headspace solid phase microextraction (HS-SPME) was used, and each sample was measured in parallel 3 times. The chromatographic column used was DB-1MS; carrier gas: helium; injection port temperature 250℃; program temperature rise: 40℃ for 3min, increased to 140℃ at a rate of 4℃ / min, maintained for 2min, increased to 240℃ at 6℃ / min, maintained for 12min; flow rate: 1mL / min; injection mode: splitless injection. Mass spectrometry conditions: electron bombardment energy: 70eV; ion source temperature: 230℃; mass scanning range set between m / z 20 and 350amu. The types, names and contents of volatile flavor substances in each sample are shown in Table 6. Figure 8 shown.

[0094] Table 6 Types, names and contents of volatile flavor substances in four cheese samples

[0095]

[0096]

[0097]

[0098] Note: NA means not detected

[0099] From Table 6 and Figure 8 It can be seen that the types and contents of flavor substances in wheat germ goat cheese are significantly different from those in other samples. Compared with goat cheese and two commercially available goat cheese products, the wheat germ goat cheese product has a softer overall flavor, which effectively weakens the mutton smell in goat cheese. The content of acidic substances such as butyric acid, caproic acid and caprylic acid related to the mutton smell of goat cheese in wheat germ goat cheese is significantly reduced, which improves consumer acceptance and has flavor characteristics that are easy for consumers to accept.

[0100] 4. Antioxidant performance analysis

[0101] The samples were wheat germ goat cheese prepared under the optimal process conditions in the orthogonal experiment, goat cheese prepared without wheat germ powder in S2, commercial goat cheese product 1, and commercial goat cheese product 2. The DPPH radical scavenging activity of the four samples was analyzed. 1g of sample was weighed and added to 9mL of pure water. After sufficient homogenization, it was centrifuged at 6000rpm for 10min, and the supernatant was filtered to obtain the sample solution. 500μL of the sample solution was added with 2mL of 0.1mmol / L DPPH radical ethanol solution, incubated in a dark environment at room temperature for 30min, and the absorbance was measured at a wavelength of 517nm using a spectrophotometer. The DPPH radical scavenging rate was calculated according to the following formula. The calculation results are shown in Table 7.

[0102]

[0103] In the formula, A0 is the absorbance of the sample; A1 is the absorbance of the control containing 500 μL of sample and 2 mL of ethanol solution; A2 is the absorbance of the blank containing 500 μL of pure water and 2 mL of DPPH free radical ethanol solution.

[0104] Table 7 Analysis of antioxidant properties of four cheese samples

[0105]

[0106] As shown in Table 7, the DPPH free radical scavenging rate of wheat germ goat cheese was significantly higher than that of the other three groups of samples, and the antioxidant capacity was excellent, indicating that the addition of wheat germ was beneficial to improving the antioxidant functional properties of goat cheese. This product has excellent antioxidant properties and meets people's expectations for functional foods.

[0107] Example 4

[0108] This example provides the physical pictures and flavors of goat cheese produced under different processes.

[0109] Experiment 1: The difference between the optimal process conditions in the orthogonal experiment of Example 2 is that the thickness of the raw wheat germ in S1 is 0.5 cm, and it is baked in an oven at 150°C for 10 minutes; in S2, it is sterilized at 60°C for 45 minutes; in S3, it is kept at 44°C; in S4, it is left to stand for 20 minutes to obtain curd; in S5, it is cut into cubes with a side length of 0.5 cm; in S6, it is soaked in sterilized 2wt% saline for 50 minutes. The prepared wheat germ goat milk cheese has uniform color, rich wheat flavor and milk flavor, moderate sourness, and moderate hardness, smoothness and fineness.

[0110] Experiment 2: The difference between the optimal process conditions in the orthogonal experiment of Example 2 is that the thickness of the raw wheat germ in S1 is 1.5 cm, and it is baked in an oven at 190°C for 20 minutes; in S2, it is sterilized at 75°C for 15 minutes; in S3, it is kept at 36°C; in S4, it is left to stand for 50 minutes to obtain curd; in S5, it is cut into cubes with a side length of 4.5 cm; in S6, it is soaked in sterilized 5wt% saline for 20 minutes. The prepared wheat germ goat milk cheese has uniform color, rich wheat flavor and milk flavor, moderate sourness, and moderate hardness, smoothness and fineness.

[0111] Comparative experiment 1: The difference between the optimal process conditions in the orthogonal experiment of Example 2 is that no wheat germ powder is added, and the prepared sheep milk cheese product is as follows Fig. 9 As shown. Fig. 9 It can be seen that the finished goat cheese without wheat germ powder is white in color, hard and fragile in texture, has milk residue on the surface, and has a strong smell.

[0112] Comparative experiment 2: The difference between the optimal process conditions in the orthogonal experiment of Example 2 is that the wheat germ powder in S1 is not roasted, and the prepared wheat germ goat cheese product is as follows: Fig.10 As shown. Fig.10 It can be seen that after adding unroasted wheat germ powder, the finished goat cheese is brown-yellow and white in color, and has a distinct wheat smell and the bitter taste of raw wheat germ, and the quality of the finished product is poor.

[0113] Comparative experiment 3: The difference between the optimal process conditions in the orthogonal experiment of Example 2 is that after preparing the goat milk curd, the wheat germ powder is mixed into the curd to form the finished wheat germ goat milk cheese. Fig.11 As shown. Fig.11 It can be seen that the appearance of the finished wheat germ goat cheese made by mixing wheat germ powder into the curd is uneven. This is because when wheat germ powder is added to the curd, the powder will clump and it is difficult to disperse evenly. In addition, the stirring process destroys the structure of the goat milk curd, resulting in many cracks on the surface of the finished product and poor molding.

[0114] Samples from Experiment 1, Experiment 2, Comparative Experiment 1, Comparative Experiment 2, and Comparative Experiment 3 were selected for sensory evaluation, and 20 volunteers were selected to evaluate the prepared wheat germ goat cheese using the wheat germ goat cheese sensory evaluation table (Table 1). The sensory evaluation results are shown in Table 1. Fig.12 As shown, the sensory evaluation results of samples in Experiment 1 and Experiment 2 were relatively good, and the total sensory evaluation scores were all 80 points or above. In contrast, the sensory evaluation results of the comparative examples were lower. Comparative Example 1 did not add wheat germ powder, and its external smell, taste and mouthfeel scores were all low, which was not popular with consumers. Comparative Example 2 added raw wheat germ powder, and the appearance, smell and taste were poor. Comparative Example 3 mixed wheat germ powder into the curd to form, and the appearance and taste of the finished product were poor.

[0115] The embodiments described above are part of the embodiments of the present invention, but not all of them. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. All other embodiments obtained without creative work and related deductions and substitutions made by ordinary technicians in the field under the conditions of the concept of the present invention belong to the scope of protection of the present invention.

Claims

1. A method for preparing wheat germ goat cheese, characterized in that: include: Mixing raw goat milk with wheat germ powder to obtain mixed raw milk; adding a fermentation agent to the mixed raw milk and fermenting at a constant temperature to obtain a fermented mixed milk; Adding calcium chloride solution and rennet to the fermented mixed milk and letting it stand to obtain curd; The wheat germ goat cheese is obtained by draining whey from the curd and soaking in salt water; The added amount of the wheat germ powder is 0-6.0% of the mass of the raw goat milk.

2. The preparation method according to claim 1, characterized in that: The preparation of the wheat germ powder comprises baking raw wheat germ at 150-190° C. for 10-20 minutes, and then crushing and sieving.

3. The preparation method according to claim 1, characterized in that: The raw goat milk and wheat germ powder are mixed and then heated and sterilized; The temperature of the heating sterilization is 60-75° C., and the time of the heating sterilization is 15-45 minutes.

4. The preparation method according to claim 1, characterized in that: The mixed raw milk is cooled to 35-45° C. before adding the fermentation agent.

5. The preparation method according to claim 1, characterized in that: Calculated by the volume of raw goat milk, the added amount of the leavening agent is 1.0 g / L to 5.0 g / L.

6. The preparation method according to claim 1, characterized in that: The temperature of the constant temperature fermentation is 36-44°C; The constant temperature fermentation is carried out until the pH value is 6.3 to 5.

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7. The preparation method according to claim 1, characterized in that: The volume concentration of the calcium chloride solution is 15%; Based on the volume of raw goat milk, the amount of calcium chloride solution added is 2.0 g / L; Calculated by the volume of raw goat milk, the added amount of rennet is 0.2-1.0 g / L.

8. The preparation method according to claim 1, characterized in that: The whey is drained from the coagulated milk until the pH of the precipitated whey is 5.2-4.

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9. The preparation method according to claim 1, characterized in that: The mass concentration of the brine in the brine immersion is 2-5%, and the brine immersion time is 20-50 minutes.

10. A wheat germ goat cheese, characterized in that: The method is prepared according to any one of claims 1 to 9.

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