Microbial solid-state fermentation method for improving eating quality of brown rice and application of microbial solid-state fermentation method

Abstract

The invention belongs to the field of solid-state fermentation, discloses a microbial solid-state fermentation method for improving the eating quality of brown rice and application, and aims to solve the problems that the brown rice is not easy to cook, rough in taste and the like. The influence of microbial solid state fermentation on the soaking water absorption rate, pH, cooking characteristics, sensory quality, texture characteristics, microstructure and thermodynamic properties of brown rice is studied. Results show that compared with unfermented brown rice, the cooking characteristic and the eating quality of the brown rice subjected to solid state fermentation of different microorganisms are improved; the soaking water absorption rate is increased, the optimal cooking time is shortened, the hardness is reduced, and the sensory quality is improved. In addition, the integrity of the cortex structure of the brown rice is destroyed by the solid fermentation treatment, and the thermodynamic property of the brown rice starch is changed, so that the brown rice starch is more easily gelatinized, and the brown rice is easier to cook and the hardness is reduced. Compared with solid state fermentation results of different microorganisms, the mixed fermentation effect of the lactic acid bacteria and the rhizopus oryzae is the best, and the cooking characteristic and the eating quality of the brown rice are remarkably improved.

Description

technical field

[0001] The invention belongs to the field of solid-state fermentation, and in particular relates to a microbial solid-state fermentation method and application for improving the eating quality of brown rice. Background technique

[0002] Brown rice is a typical whole grain, rich in various nutrients and physiologically active substances, and is a "nutrient package". However, the cortex of brown rice contains more crude fiber and contains a waxy layer, which leads to problems such as difficult cooking and rough taste of brown rice, which restricts the application of brown rice in staple food and limits the development of brown rice food. Improving the properties of brown rice cortex is the key to solve this problem. At present, the processing methods of brown rice cortex mainly include milling, soaking, freezing and thawing, germination, enzymatic hydrolysis, fermentation, pregelatinization, extrusion puffing, microwave treatment, irradiation treatment, ultra...

Examples

Embodiment 1

[0040] The solid-state fermentation process of embodiment 1 brown rice

[0041] The method includes the following steps: activation and expansion of strains → brown rice cleaning and impurity removal → washing and soaking → high-pressure sterilization → inoculation → fermentation → regular material turning → drying → packaging and refrigeration.

[0042] Add the frozen lactic acid bacteria seed solution with an inoculum of 1% by volume to 100mL of MRS broth medium; add the frozen yeast seed solution with an inoculum of 1% by volume to In 100 mL of YPD medium; add the frozen Rhizopus oryzae seed solution to 1% inoculum volume in 100 mL of potato dextrose broth medium PDB. Then place the three kinds of bacterial suspensions in a shaker at 28-37°C and 150r / min for 10-30 hours; then take 1 mL from the bacterial suspensions and add them to 100 mL of the corresponding culture medium for the second-generation culture , cultivated for 10-12 hours. Finally, the bacterial solution in ...

Embodiment 2

[0046] The mensuration of embodiment 2 immersing water absorption rate

[0047] Take 3.0g of brown rice and 30.0mL of distilled water and place them in a centrifuge tube. After soaking at room temperature for a certain period of time, drain the water on the surface of the brown rice and measure its quality. The formula for calculating the soaking water absorption rate is as follows.

[0048]

[0049] In the formula, W 1 is the weight of brown rice before soaking, g; W 2 is the weight of brown rice after soaking, g.

[0050] Effects of solid-state fermentation of different microorganisms on soaking water absorption of brown rice as follows: figure 1 shown. After soaking for 0-0.5h, the soaking water absorption rate of brown rice increased rapidly. After soaking for 1 hour, the soaking water absorption rate of different solid-state fermented brown rice slowed down and even stabilized, while the soaking water absorption rate of unfermented brown rice still increased gradu...

Embodiment 3

[0052] The mensuration of embodiment 3pH

[0053] Weigh 10.0 g of brown rice and 20 mL of boiling water and mix thoroughly for 1 h. After the mixture is cooled, centrifuge at 3000 r / min for 20 min, and measure the pH of the supernatant.

[0054] Effects of solid-state fermentation of different microorganisms on the pH of brown rice such as figure 2 shown. The pH of unfermented brown rice is 6.80, while the pH of lactic acid bacteria, saccharomyces, rhizopus oryzae, lactic acid bacteria + yeast, lactic acid bacteria + rhizopus oryzae, and the fermented brown rice of the comparative example are 5.08, 5.70, 4.88, 5.18, 4.86, 4.98, respectively. During the fermentation process, yeast can produce lactic acid; lactic acid bacteria mainly produce lactic acid, and also produce organic acids such as acetic acid and propionic acid. The accumulation of organic acids reduces the pH of the system. During the metabolic process, Rhizopus oryzae can produce organic acids such as lactic aci...

technical field

[0001] The invention belongs to the field of solid-state fermentation, and in particular relates to a microbial solid-state fermentation method and application for improving the eating quality of brown rice. Background technique

[0002] Brown rice is a typical whole grain, rich in various nutrients and physiologically active substances, and is a "nutrient package". However, the cortex of brown rice contains more crude fiber and contains a waxy layer, which leads to problems such as difficult cooking and rough taste of brown rice, which restricts the application of brown rice in staple food and limits the development of brown rice food. Improving the properties of brown rice cortex is the key to solve this problem. At present, the processing methods of brown rice cortex mainly include milling, soaking, freezing and thawing, germination, enzymatic hydrolysis, fermentation, pregelatinization, extrusion puffing, microwave treatment, irradiation treatment, ultra...

Examples

Embodiment 1

[0040] The solid-state fermentation process of embodiment 1 brown rice

[0041] The method includes the following steps: activation and expansion of strains → brown rice cleaning and impurity removal → washing and soaking → high-pressure sterilization → inoculation → fermentation → regular material turning → drying → packaging and refrigeration.

[0042] Add the frozen lactic acid bacteria seed solution with an inoculum of 1% by volume to 100mL of MRS broth medium; add the frozen yeast seed solution with an inoculum of 1% by volume to In 100 mL of YPD medium; add the frozen Rhizopus oryzae seed solution to 1% inoculum volume in 100 mL of potato dextrose broth medium PDB. Then place the three kinds of bacterial suspensions in a shaker at 28-37°C and 150r / min for 10-30 hours; then take 1 mL from the bacterial suspensions and add them to 100 mL of the corresponding culture medium for the second-generation culture , cultivated for 10-12 hours. Finally, the bacterial solution in ...

Embodiment 2

[0046] The mensuration of embodiment 2 immersing water absorption rate

[0047] Take 3.0g of brown rice and 30.0mL of distilled water and place them in a centrifuge tube. After soaking at room temperature for a certain period of time, drain the water on the surface of the brown rice and measure its quality. The formula for calculating the soaking water absorption rate is as follows.

[0048]

[0049] In the formula, W 1 is the weight of brown rice before soaking, g; W 2 is the weight of brown rice after soaking, g.

[0050] Effects of solid-state fermentation of different microorganisms on soaking water absorption of brown rice as follows: figure 1 shown. After soaking for 0-0.5h, the soaking water absorption rate of brown rice increased rapidly. After soaking for 1 hour, the soaking water absorption rate of different solid-state fermented brown rice slowed down and even stabilized, while the soaking water absorption rate of unfermented brown rice still increased gradu...

Embodiment 3

[0052] The mensuration of embodiment 3pH

[0053] Weigh 10.0 g of brown rice and 20 mL of boiling water and mix thoroughly for 1 h. After the mixture is cooled, centrifuge at 3000 r / min for 20 min, and measure the pH of the supernatant.

[0054] Effects of solid-state fermentation of different microorganisms on the pH of brown rice such as figure 2 shown. The pH of unfermented brown rice is 6.80, while the pH of lactic acid bacteria, saccharomyces, rhizopus oryzae, lactic acid bacteria + yeast, lactic acid bacteria + rhizopus oryzae, and the fermented brown rice of the comparative example are 5.08, 5.70, 4.88, 5.18, 4.86, 4.98, respectively. During the fermentation process, yeast can produce lactic acid; lactic acid bacteria mainly produce lactic acid, and also produce organic acids such as acetic acid and propionic acid. The accumulation of organic acids reduces the pH of the system. During the metabolic process, Rhizopus oryzae can produce organic acids such as lactic aci...

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