Preparation technology of pitaya flower probiotic fermented beverage

Abstract

The invention discloses a preparation process of a pitaya flower probiotic fermented beverage, which comprises the following steps: taking pitaya flower liquid, adding a lactic acid bacteria compound leavening agent, and fermenting at 30-45 DEG C for 30-47 hours. The obtained pitaya flower probiotic fermented beverage is yellow, uniform and glossy, has the inherent fragrance of pitaya flowers, and is moderate in sour-sweet ratio, fine and soft in taste and unique in flavor. The total amounts of pH, soluble solids, total acids, reducing sugar, total flavonoids and lactic acid bacteria of the obtained pitaya flower probiotic fermented beverage are 4.72%, 14.50%, 3.94 g / 100 mL, 7.94 g / 100 g, 3.75 mg / g and 6.82 * 10 < 6 > CFU / mL respectively. A research and development thought is provided for further developing a plant type probiotic fermented beverage with the pitaya flower flavor and a health-care effect.

Description

Technical Field

[0001] The invention relates to a preparation process of a probiotic fermented beverage, in particular to a preparation process of a pitaya flower probiotic fermented beverage. Background Art

[0002] Pitaya (Hylocereus undatus), also known as love fruit, red dragon fruit, fairy honey fruit, etc., is a fruit plant of the genus Selenicereus and Hylocereus of the Cactaceae family. Pitaya flowers have high nutritional value, medicinal value and ornamental value. Its pollen has a high content of anthocyanins, and has the characteristics of high nutrition, low calories, low fat, rich in vitamins and amino acids. The whole flower can be eaten raw or processed. Studies have shown that pitaya flowers are rich in vitamins, amino acids, minerals, anthocyanins, water-soluble dietary fiber and other nutrients necessary for the human body. They can effectively promote gastrointestinal motility, prevent constipation and prevent intestinal cancer. They have antioxidant, anti-aging, blood sugar lowering, blood lipid lowering, blood vessel softening, cardiovascular and cerebrovascular protection, antibacterial and antiviral effects. The rare plant albumin rich in pitaya flowers can also eliminate heavy metals in the body and avoid the harm of heavy metal residues. Dragon fruit flowers have a wide range of uses in both medicine and food, and their nutritional content is higher than that of the fruit. However, they are currently mostly used as soup ingredients, and their commercial value has not been fully explored. Using dragon fruit flower fermented beverages not only has a unique flavor, but also better preserves the original nutrients and natural active substances in the material. Developing probiotic fermented dragon fruit flower beverages is a new way to increase the economic benefits of producers and operators, and is an important research direction for the development of the economic value of dragon fruit.

[0003] At present, the application of different types of probiotics to ferment and produce fruit beverages is a research hotspot, and there are related reports both at home and abroad. However, there are no reports on the probiotic fermentation research using pitaya flowers as raw materials. Summary of the invention

[0004] The invention provides a preparation process of a pitaya flower probiotic fermented beverage.

[0005] Specifically, the preparation process of the pitaya flower probiotic fermented beverage is to take pitaya flower liquid, add lactic acid bacteria composite fermentation agent, and ferment at 30-45°C for 30-47 hours.

[0006] In every 100 ml of pitaya flower liquid, the inoculation amount of lactic acid bacteria composite fermentation agent is 0.50-1.50 g.

[0007] Preferably, the inoculation amount of the lactic acid bacteria composite fermentation agent in every 100 ml of pitaya flower liquid is 1.08-1.10 g, more preferably, 1.10 g.

[0008] The fermentation conditions of the present invention are preferably: fermentation temperature 42° C., and fermentation time 31-32 h.

[0009] In one embodiment, pitaya flower liquid is prepared by the following method:

[0010] (1) Preparing a pitaya flower extract: cutting dried pitaya flowers into segments, crushing them, adding water to extract them, filtering them, and obtaining a filtrate;

[0011] (2) Enzymatic hydrolysis and clarification: distilled water is added to the filtrate, pectinase and cellulase are added, enzymatic hydrolysis is performed, standing for clarification, and filtering is performed to obtain pitaya flower clarified liquid;

[0012] (3) Preparation and homogenization: Add carbon source to the pitaya flower clarified liquid and homogenize;

[0013] (4) Sterilization and enzyme inactivation.

[0014] In step (2), the ratio of filtrate to distilled water is 1:30; the ratio of pectinase to cellulase is 1:1 (W / W).

[0015] In step (2), the enzymatic hydrolysis conditions are 53° C. for 2 h and a standing time of 2-4 h.

[0016] In step (3), homogenization is performed using a high-pressure homogenizer at 15 MPa.

[0017] In step (4), the sterilization and enzyme inactivation conditions are 95° C. for 20 min.

[0018] The present invention optimizes the process parameters of the dragon fruit flower probiotic fermented beverage by using a response surface on the basis of a single factor experiment. The results show that the factors affecting the sensory score of the dragon fruit flower probiotic fermented beverage are the amount of starter added, the fermentation temperature, and the fermentation time. The present invention optimizes the fermentation process conditions so that the dragon fruit flower probiotic fermented beverage is yellow, uniform and shiny, has the inherent fragrance of dragon fruit flowers, has a moderate sweet-sour ratio, has a delicate and soft taste, and has a unique flavor.

[0019] The pH, soluble solids, total acid, reducing sugar, total flavonoids and total lactic acid bacteria of the pitaya flower probiotic fermented beverage obtained by the present invention are 4.72, 14.50%, 3.94 g / 100 mL, 7.94 g / 100 g, 3.75 mg / g and 6.82×10 6 CFU / mL. This provides research and development ideas for further developing plant-based probiotic fermented beverages with dragon fruit flower flavor and health benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 To study the effect of the amount of starter culture added on the sensory score and total acid content of fermented beverages.

[0021] Figure 2The effect of fermentation temperature on the sensory score and total acid content of fermented beverages.

[0022] Figure 3 The effect of fermentation time on the sensory score and total acid content of fermented beverages.

[0023] Figure 4A-4F Response surfaces and contour lines for the interaction effects of various factors on sensory scores. Specific embodiments

[0024] 1. Experimental Methods

[0025] 1.1 Raw materials and reagents

[0026] Pitaya flowers were provided by Guangxi Zhuangxiang Valley Agricultural Technology Co., Ltd.; lactic acid bacteria compound fermentation agent (the ratio between Lactobacillus plantarum and Streptococcus thermophilus is 1:1): Angel Yeast Co., Ltd.; white sugar: commercially available; pectinase, cellulase, xanthan gum, carrageenan, sodium carboxymethyl cellulose (all food grade): Henan Wanbang Industrial Co., Ltd.; phenolphthalein, zinc acetate, potassium ferrocyanide, cupric sulfate, sodium nitrite (all analytical grade): Sinopharm Chemical Reagent Co., Ltd.; sodium hydroxide, citric acid (all analytical grade): Tianjin Fuchen Chemical Reagent Factory; glucose, rutin (both standard products): China Food and Drug Inspection Institute.

[0027] 1.2 Instruments and Equipment

[0028] MQD S2R constant temperature incubator: Shanghai Minquan Instrument Co., Ltd.; SN510C vertical pressure steam sterilizer: Chongqing Yamato Technology Co., Ltd.; HH-S4 constant temperature water bath: Jiangsu Jinyi Instrument Technology Co., Ltd.; FW102 crusher: Tianjin Test Instrument Co., Ltd.; WYA Abbe refractometer: Shanghai Yidian Physical Optical Instrument Co., Ltd.; 1901870S frozen centrifuge: Ohaus Instrument Co., Ltd.; GYB60-6S high pressure homogenizer: Shanghai Donghua High Pressure Homogenizer Factory; PX224ZH one-tenth electronic balance: Ohaus Instrument Co., Ltd.; ST5000 pH meter: Ohaus Instrument Co., Ltd.; UV-1700 ultraviolet-visible spectrophotometer: Shimadzu Instrument Co., Ltd., Japan.

[0029] 1.3 Methods

[0030] 1.3.1 Process flow

[0031] Dragon fruit flower → picking → crushing → extraction → enzymatic hydrolysis → filtration and clarification → centrifugal separation → blending → homogenization → sterilization and cooling → fermentation → finished product refrigeration.

[0032] 1.3.2 Operation points

[0033] (1) Preparation of pitaya flower extract: dry pitaya flowers to remove rotten flower heads, miscellaneous leaves, branches and other foreign matter, rinse with clean water to remove dust and impurities on the surface, wash and cut into small pieces of 2-3 cm, crush with a grinder, extract at a constant temperature of 75° C. for 2 h, filter with sterilized 200-mesh gauze, and set aside.

[0034] (2) Enzymatic hydrolysis and clarification: Add distilled water at a solid-liquid ratio of 1:30, add an appropriate amount of pectinase and cellulase 1:1 (W / W) mixture, perform enzymatic hydrolysis at 53°C for 2 h, let stand for 2-4 h to clarify, and remove fine suspended particles in the extract.

[0035] (3) Preparation and homogenization: Add the pitaya flower clarified liquid in proportion, add 8% of the total volume of white sugar, and use a high-pressure homogenizer to homogenize at 15 MPa.

[0036] (4) Sterilization: Place the prepared pitaya flower liquid at 95°C for 20 minutes to sterilize and inactivate enzymes, and then cool to room temperature.

[0037] 1.3.3 Single factor test of fermentation process

[0038] 100mL pitaya flower liquid was measured and added with 8% white sugar to dissolve, sterilize and cool, and then aseptically operated. The amount of fermentation agent added (0.50g, 1.00g, 1.50g, 2.00g, 2.50g), fermentation temperature (27℃, 32℃, 37℃, 42℃, 47℃), and fermentation time (18h, 24h, 30h, 36h, 42h) were selected for single factor test. Each group of experiments was repeated 3 times, and the results were averaged. The sensory score and total acid were used as evaluation indicators to determine the influence of various factors on the quality of pitaya flower fermented beverage.

[0039] 1.3.4 Optimization of fermentation process by response surface analysis

[0040] Taking the results obtained from the single-factor experimental design as the center point, Design Expert 8.0.6 software was used to recode the main factors (starter addition amount, fermentation temperature, and fermentation time) using the median combination. The sensory score of the fermented product (Y) was used as the response value. The Box-Benhnken central combination experimental design principle was used to design a response surface experiment with three factors and three levels, as shown in Table 1.

[0041] Table 1 Response surface factors and levels

[0042]

[0043] 1.3.5 Physical and chemical index testing

[0044] pH value: measured by pH meter; soluble solids: measured by handheld refractometer; total acid (calculated as citric acid): in accordance with GB / T12456-2008 "Determination of total acid in food"

[22] Titration method; reducing sugar (measured in glucose): in accordance with GB / T5009.7-2016 "Determination of reducing sugar in food"

[23] Direct titration method; total flavonoids: by spectrophotometry

[24] Determination; Total lactic acid bacteria colony count: Determined in accordance with GB 4789.35-2016 "Food Microbiology Examination - Lactic Acid Bacteria Examination".

[0045] 1.3.6 Sensory evaluation

[0046] A sensory evaluation panel of 10 people with a professional background in food was selected to give a comprehensive score according to the evaluation criteria. Evaluation criteria: The color, flavor, taste, and tissue morphology of the pitaya flower probiotic fermented beverage were evaluated, with a full score of 100, and the average score was used as the score of the fermented beverage. The sensory evaluation criteria are detailed in Table 2.

[0047] Table 2 Sensory scoring standards for pitaya flower probiotic fermented beverages

[0048]

[0049] 1.3.7 Data Processing

[0050] The data were statistically analyzed and plotted using the data software Graphpadprism 7, SPSS19.0 software was used for analysis of variance (ANOVA), and Design-Expert8.0.6 software was used to analyze the data and plot.

[0051] 2 Results and analysis

[0052] 2.1 Single factor experiment on process optimization of pitaya flower probiotic fermented beverage

[0053] 2.1.1 Effect of starter culture addition on the quality of pitaya flower probiotic fermented beverage

[0054] Sensory scores and acidity of beverages with different fermentation agent addition amounts are shown in Figure 1. The main change of the probiotic fermented pitaya flower beverage is that lactic acid bacteria use sugars to produce organic acids, giving the fermented beverage a soft sour taste. With the increase of the amount of fermentation agent added, the sensory score of the pitaya flower probiotic fermented beverage gradually increased. When the fermentation agent inoculation amount is 0.5g, the taste of the beverage is slightly light; when the fermentation agent addition amount is 1.0g, the beverage is sweet and sour, and the sensory score reaches the highest 88 points; with the increase of the addition amount, the sensory score decreases, which may be due to the excessive addition of bacteria, resulting in too fast substrate consumption and excessive acid production. The sour taste of the product is too obvious, covering up the flavor of the beverage itself. The total acid content also shows a trend of first increasing and then decreasing with the increase of the amount of fermentation agent added. When the addition amount is 1.5g, the total acid content is the highest. It can be seen that only the appropriate inoculation amount can optimize the reproduction and acid production capacity of lactic acid bacteria. Comprehensively analyzing the two factors of sensory score and total acid content, the optimal inoculation amount of the fermentation agent should be 1.0g-1.5g. 2.1.2 Effect of fermentation temperature on the quality of pitaya flower probiotic fermented beverage

[0055] Sensory scores and acidity of beverages at different fermentation temperatures Figure 2 . As the fermentation temperature increases, the sensory score and total acid content both show a trend of first increasing and then decreasing. The sensory score and total acid content both reach their maximum values ​​at 37°C, which are 87 points and 3.73g / 100mL, respectively. The reason for this is that temperature is closely related to the activity of lactic acid bacteria. When the fermentation temperature is too low, the metabolic activity of lactic acid bacteria is very weak, and they cannot grow and reproduce in large quantities, and the acid production is low; when the fermentation temperature is too high, lactic acid bacteria reproduce rapidly and metabolize vigorously, and their growth and metabolism are inhibited, thereby affecting the acid production. Comprehensively analyzing the two factors of sensory score and total acid content, the optimal fermentation temperature should be 37°C.

[0056] 2.1.3 Effect of fermentation time on the quality of pitaya flower probiotic fermented beverage

[0057] Sensory scores and acidity of beverages with different fermentation times Figure 3 . As the fermentation time increases, the sensory score and total acid content show an upward trend. When the fermentation time reaches 30 hours, the sensory score and total acid content remain stable. It may be that in the early 18 to 30 hours of fermentation, lactic acid bacteria use the fermentation matrix to reproduce and produce acid, which makes the acidity of the product show an upward trend, thereby improving the flavor of the product. At 30 hours of fermentation, the sensory score reaches a maximum value of 86 points. As the fermentation time increases, lactic acid bacteria continue to use sugar to produce acid. When the pH value drops to a certain level, the lactic acid bacteria themselves are inhibited, resulting in a decrease in acid production, and the total acid content tends to stabilize. Comprehensively analyzing the two factors of sensory score and total acid content, the optimal fermentation time should be 30 hours.

[0058] 2.2 Optimization of pitaya flower probiotic fermentation beverage process by response surface experiment

[0059] 2.2.1 Response surface design and variance analysis

[0060] According to the results of the single-factor test, a response surface test was conducted with the amount of fermentation agent added (A), fermentation temperature (B), and fermentation time (C) as independent variables and the sensory score (Y) as the dependent variable. The Box-Benhken test design and results are shown in Table 3, and the results of the significance test and variance analysis are shown in Table 4. The quadratic regression equation was fitted to the data in Table 3 using Design Expert 8.0.6 software, and the quadratic polynomial regression equation was obtained:

[0061] Y=84.64-1.81A+1.63B+0.69C-0.25AB-0.13AC-0.50BC-3.88A 2 +1.49B 2 -1.13C 2

[0062] Table 3 Response surface design and results of probiotic fermented beverage process optimization

[0063]

[0064] Table 4 Analysis of variance in response surface experiments

[0065]

[0066] The results of the model variance analysis and significance test are shown in Table 4. The obtained regression model has significant differences (P<0.05). The lack of fit term is used to indicate the degree of fit between the model and the experiment, that is, the degree of difference between the two. The lack of fit term is not significant (P>0.05), indicating that the regression equation model has a good fit with the actual experiment and can well predict the experimental values. Therefore, the regression equation can be used to replace the actual points of the experiment to analyze the experimental results. The coefficient of variation (CV) value of the sensory score is relatively low (1.00%), indicating that the precision and reliability of the experimental value are high. In summary, the model fit is in line with the principles of mathematical statistics, and the process of pitaya flower probiotic fermented beverage can be predicted by this equation. The F value results show that the order of influence on the sensory score is: the amount of fermentation agent added> fermentation temperature> fermentation time. According to the variance analysis of the regression model, the linear terms A and B have extremely significant effects on the sensory evaluation (P<0.01), and C has no significant effect on it; the interaction terms AB, AC, and the quadratic term A 2 , B 2 , C 2 The sensory evaluation was significantly affected (P<0.05).

[0067] 2.2.2 Response surface interaction analysis of each factor

[0068] Design Expert 8.0.6 software was used to interactively analyze the three factors affecting the dragon fruit flower probiotic fermented beverage. The results are shown in Figure 4A -F.

[0069] According to the interaction between factors and regression equation, response surface analysis diagram and contour map are made. Figure 4A -F can more intuitively show the interaction between various factors on the various parameters of pitaya flower fermented beverage. The steeper the slope of the contour line trend, the more significant the mutual influence between factors; the closer the contour line is to the ellipse, the greater the influence. Figure 4A-4C It was found that the amount of probiotic compound fermentation agent and fermentation temperature had a significant effect on the sensory score, but the fermentation time had no significant effect, indicating that by effectively controlling the fermentation temperature and the amount of fermentation agent, a beverage with a higher score and better taste can be obtained. Figure 4D , Figure 4E It can be seen that with the increase of each factor, the sensory score shows a trend of first increasing and then decreasing or continuously increasing, and the response surface shape is steep, indicating that the interaction between the two is significant, which is consistent with the results of variance analysis; Figure 4F It can be seen that the sensory score increased with the increase of fermentation temperature, and increased slowly with the increase of fermentation time. The interaction between fermentation temperature and fermentation time was not significant (P>0.05).

[0070] 2.2.3 Determination and verification of optimal fermentation conditions

[0071] In order to determine the optimal point value, the design expert 8.0.6 software was used to optimize the fermentation process, and the optimal solution was obtained as follows: the amount of fermentation agent added was 1.08g, the fermentation temperature was 42℃, the fermentation time was 31.29h, and the sensory score prediction value of the pitaya flower probiotic fermented beverage was 87.34 points. Considering the convenience of actual operation, the optimal conditions were selected as the amount of fermentation agent added was 1.10g, the fermentation temperature was 42℃, and the fermentation time was 31h. In order to verify the reliability of the optimization results, three verification tests were carried out under the optimized conditions, and the actual sensory score of the pitaya flower probiotic fermented beverage was measured to be 88.5 points, which was close to the predicted result, so this was selected as the fermentation process parameter of the pitaya flower probiotic fermented beverage.

[0072] 2.3 Quality analysis of pitaya flower probiotic fermented beverage

[0073] The quality indicators of the pitaya flower probiotic fermented beverage fermented under the optimal fermentation conditions are shown in Table 5. The pH, soluble solids, total acid, reducing sugar, total flavonoids, and total lactic acid bacteria of the pitaya flower probiotic fermented beverage are 4.72, 14.50%, 3.94 g / 100 mL, 7.94 g / 100 g, 3.75 mg / g, and 6.82 × 10 6CFU / mL.

[0074] Table 5 Quality indexes of pitaya flower probiotic fermentation

[0075]

[0076]

[0077] 3 Conclusion

[0078] Based on the single factor experiment, the response surface was used to optimize the process parameters of pitaya flower probiotic fermented beverage. The results showed that the factors affecting the sensory score of pitaya flower probiotic fermented beverage were the amount of fermentation agent, fermentation temperature, and fermentation time, respectively; the optimal fermentation process conditions were: 1.10g of fermentation agent, 42℃ of fermentation temperature, and 31h of fermentation time. Under these fermentation conditions, the sensory score of pitaya flower probiotic fermented beverage reached 88.5 points. It was yellow, uniform and shiny, with the inherent fragrance of pitaya flower, moderate sweet and sour ratio, delicate and soft taste, and unique flavor. After fermentation, the pH, soluble solids, total acid, reducing sugar, total flavonoids, and total lactic acid bacteria of pitaya flower probiotic fermented beverage were 4.72, 14.50%, 3.94g / 100mL, 7.94g / 100g, 3.75mg / g, and 6.82×10 6 CFU / mL. This provides research and development ideas for further developing plant-based probiotic fermented beverages with dragon fruit flower flavor and health benefits.

Claims

1. A preparation process of a pitaya flower probiotic fermented beverage, characterized in that: Take pitaya flower juice, add lactic acid bacteria compound fermentation agent, and ferment at 30-45℃ for 30-47h.

2. The preparation process of the pitaya flower probiotic fermented beverage according to claim 1, characterized in that: In every 100 ml of the pitaya flower liquid, the inoculation amount of the lactic acid bacteria composite fermentation agent is 0.50-1.50 g.

3. The preparation process of the dragon fruit flower probiotic fermented beverage according to claim 1, characterized in that: In every 100 ml of the pitaya flower liquid, the inoculation amount of the lactic acid bacteria composite fermentation agent is 1.08-1.10 g.

4. The preparation process of the pitaya flower probiotic fermented beverage according to claim 1, characterized in that: The pitaya flower liquid is added with a lactic acid bacteria composite fermentation agent and fermented at 30-45° C. for 31-32 hours.

5. The preparation process of the dragon fruit flower probiotic fermented beverage according to claim 1, characterized in that: In the lactic acid bacteria composite fermentation agent, the ratio between Lactobacillus plantarum and Streptococcus thermophilus is 1:

1.

6. The preparation process of the dragon fruit flower probiotic fermented beverage according to claim 1, characterized in that: The pitaya flower liquid is prepared by the following method: (1) Preparing a pitaya flower extract: cutting dried pitaya flowers into segments, crushing them, adding water to extract them, filtering them, and obtaining a filtrate; (2) Enzymatic hydrolysis and clarification: distilled water is added to the filtrate, pectinase and cellulase are added, enzymatic hydrolysis is performed, standing for clarification, and filtering is performed to obtain pitaya flower clarified liquid; (3) Preparation and homogenization: Add carbon source to the pitaya flower clarified liquid and homogenize; (4) Sterilization and enzyme inactivation.

7. The preparation process of the pitaya flower probiotic fermented beverage according to claim 6, characterized in that: In the step (2), the ratio of the filtrate to the distilled water is 1:30; the mass ratio of the pectinase to the cellulase is 1:

1.

8. The preparation process of the dragon fruit flower probiotic fermented beverage according to claim 6, characterized in that: In the step (2), the enzymatic hydrolysis conditions are 53° C. for 2 h and a standing time of 2-4 h.

9. The preparation process of the dragon fruit flower probiotic fermented beverage according to claim 6, characterized in that: In the step (3), homogenization is performed using a high-pressure homogenizer at 15 MPa.

10. The preparation process of the dragon fruit flower probiotic fermented beverage according to claim 6, characterized in that: In the step (4), the sterilization and enzyme inactivation conditions are 95° C. for 20 minutes.

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