阅读说明：本技术 一种利用大米加工副产物酸水解液制备食品胶基细菌纤维素的方法 (Method for preparing food gum-based bacterial cellulose by using acid hydrolysis liquid of rice processing byproduct ) 是由 黄超 吴沂 李志璇 黄忠英 胡勇 高静 陈云 郭娟 于 2021-11-23 设计创作，主要内容包括：本发明提供了一种利用大米加工副产物酸水解液制备食品胶基细菌纤维素的方法。在米糠或稻壳酸水解液发酵培养基中添加不同类型的食品胶,接入生产细菌纤维素的菌株进行发酵,发酵后通过碱溶液去除菌体及杂质,即得食品胶基细菌纤维素。本研究表明,在单独添加一种食品胶效果不明显时,可通过复配添加多种食品胶,起协同增效的作用,可以有效提高细菌纤维素产量及调控其质构特性。本发明利用廉价大米加工副产物的酸水解液,有效降低了发酵成本,实现了大米加工副产物的高值化利用。通过单独或复配添加食品胶进行发酵,能克服发酵环境的抑制作用,缩短发酵延迟期,有效提高细菌纤维素产率及发酵糖利用率,可实现食品胶基细菌纤维素质构特性的调控。(The invention provides a method for preparing food gum-based bacterial cellulose by using acid hydrolysis liquid which is a rice processing byproduct. Adding different types of food gum into a rice bran or rice husk acid hydrolysate fermentation medium, inoculating bacterial strains for producing bacterial cellulose for fermentation, and removing thalli and impurities through an alkali solution after fermentation to obtain the food gum-based bacterial cellulose. The research shows that when the effect of independently adding one food gum is not obvious, a plurality of food gums can be added through compounding to play a role in synergy, so that the yield of the bacterial cellulose can be effectively improved, and the texture characteristics of the bacterial cellulose can be effectively regulated and controlled. The invention utilizes the acid hydrolysis liquid of cheap rice processing byproducts, effectively reduces the fermentation cost and realizes the high-valued utilization of the rice processing byproducts. By adding food gum for fermentation independently or in a compound manner, the inhibition effect of the fermentation environment can be overcome, the fermentation delay period is shortened, the yield of bacterial cellulose and the utilization rate of fermentation sugar are effectively improved, and the regulation and control of the cellulose texture characteristics of the food gum-based bacteria can be realized.)

1. A method for preparing food gum-based bacterial cellulose by utilizing acid hydrolysis liquid which is a rice processing byproduct is characterized by comprising the following steps:

s1, adding food gum into a rice bran or rice hull acid hydrolysate fermentation medium, and sterilizing for later use;

s2, inoculating the culture medium obtained in the step S1 into a strain for producing bacterial cellulose, and fermenting at the temperature of 25-35 ℃;

and S3, treating the product fermented in the step S2 by an alkali solution to remove thalli and impurities, so as to obtain the food gum base bacterial cellulose.

2. The method of claim 1, wherein in step S1, the food gum is one or more of xanthan gum, arabic gum, microcrystalline cellulose, curdlan, chitosan, trehalose, high acyl gellan gum, and low acyl gellan gum.

3. The method as claimed in claim 1, wherein the food gum added in step S1 is xanthan gum and curdlan.

4. The method of claim 1, wherein the food gum added in step S1 is xanthan gum and high acyl gellan gum or xanthan gum and low acyl gellan gum.

5. The method according to claim 1, wherein the mass concentration of the food gum added in the step S1 is 0.05-0.8%.

6. The method according to claim 1, wherein the inoculated strain in the step S2 is Xylobacter colatoides.

7. The method as claimed in claim 1, wherein the inoculation volume ratio of the strain in step S2 is 5-15%.

8. The method according to claim 1, wherein the fermentation time in the step S2 is 3-15 days.

9. The method according to claim 1, wherein the alkaline solution used in step S3 is an aqueous solution of sodium hydroxide or potassium hydroxide.

10. The method according to claim 9, wherein the concentration of the sodium hydroxide or the potassium hydroxide is 0.25 to 1 mol/L.

Technical Field

The invention relates to the field of preparation of functional bacterial cellulose materials, in particular to a method for preparing food gum-based bacterial cellulose by using acid hydrolysis liquid which is a rice processing byproduct.

Background

The bacterial cellulose is an extracellular linear chain high molecular polysaccharide synthesized by certain bacteria, has the advantages of high water retention, high biodegradability, large Young modulus, high water absorption, good biocompatibility and the like, and is widely applied to the fields of food, cosmetics, biomedicine and the like. The research on bacterial cellulose fermentation in the prior art has two hotspots, namely, the production cost of the bacterial cellulose is reduced by utilizing a natural culture medium, and the synthesis and modification of the bacterial cellulose are completed simultaneously through in-situ fermentation.

China is one of the countries with the largest rice production in the world, the annual output is about 2 hundred million tons, the population exceeding 2/3 in China takes rice as staple food, and the rice consumption accounts for more than 6 percent of the total consumption of grain. However, the processing byproducts such as rice bran, rice hulls and the like generated in the rice processing process cannot be fully and effectively utilized, so that huge waste of rice resources is caused, the power consumption, the water consumption and the pollutant discharge are increased, and a large amount of nutrient components are lost. The rice hull is a shell outside the paddy, and contains about 40% of crude fiber (including lignin fiber and cellulose) and about 20% of pentose polymer (mainly hemicellulose), and also contains about 20% of ash and a small amount of organic compounds such as crude protein and crude fat. The rice bran is a main byproduct in the process of processing the rice into rice, accounts for 6-8% of the weight of the rice, contains 15% of protein, 16-22% of fat, 3-8% of sugar and 10% of water on average. The rice husk and the rice bran can be used as raw materials for preparing the bacterial cellulose by fermentation.

The prior art discloses a method for preparing bacterial cellulose by fermenting rice bran enzyme hydrolysate, which comprises the steps of hydrolyzing rice bran by using liquefying enzyme, cellulase and saccharifying enzyme to obtain rice bran enzyme hydrolysate, and then adding a nitrogen source, ethanol and the like into the hydrolysate for fermentation to obtain the bacterial cellulose. However, enzymatic hydrolysis of rice bran has the disadvantages of high enzyme cost and long reaction period. The rice bran hydrolysate prepared by hydrolyzing rice bran with dilute acid has low cost and short period, and is expected to overcome the defects of enzyme hydrolysis, but the bacterial cellulose prepared by fermenting rice processing byproducts (rice bran and rice hull) acid hydrolysate is only reported at present.

However, two key technical problems still exist in preparing bacterial cellulose by using rice processing by-product acid hydrolysate, and firstly, the rice processing by-product acid hydrolysate contains a fermentation inhibitor with higher concentration, so that the bacterial cellulose obtained by fermentation has low yield and long fermentation delay period; and secondly, the texture characteristics of the bacterial cellulose prepared by adopting the rice processing byproduct acid hydrolysis liquid are difficult to regulate and control. In this context, it is necessary to develop a novel fermentation technique to solve the above problems.

In order to solve the problems of increased fermentation delay period, low sugar utilization rate, low bacterial cellulose yield and the like, the subject group patent CN112695009A provides a method for preparing bacterial cellulose by in-situ fermentation, and a strain for producing the bacterial cellulose is inoculated into a culture medium containing gellan gum for in-situ fermentation, so that the fermentation delay period can be shortened, and the bacterial cellulose yield and the fermentation sugar utilization rate can be improved. However, the patent technology does not regulate and control the texture characteristics of the bacterial cellulose, and also fails to show whether the inhibition effect of the fermentation environment can be overcome by adding gellan gum into the acid hydrolysis liquid which is a byproduct in rice processing. Under the circumstances, the development of more advanced fermentation technology is needed, in particular to the technology which can overcome the inhibition of the fermentation environment, improve the yield of the bacterial cellulose and regulate and control the texture characteristics of the bacterial cellulose product. On the other hand, when the in-situ fermentation based on the addition of gellan gum alone cannot effectively overcome the inhibition of the fermentation environment, it is also necessary to develop more advanced fermentation techniques.

Disclosure of Invention

The invention aims to overcome the defects and shortcomings in the prior art and provides a method for preparing food gum-based bacterial cellulose by using acid hydrolysis liquid which is a rice processing byproduct.

The above object of the present invention is achieved by the following technical solutions:

the invention provides a method for preparing food gum-based bacterial cellulose by utilizing rice processing byproduct acid hydrolysis liquid, which comprises the steps of inoculating a strain for producing bacterial cellulose into a culture medium containing food gum for fermentation, adding the food gum, and particularly when the effect of adding one food gum alone is not obvious, obviously improving the yield of the bacterial cellulose through the synergistic effect formed by adding different food gums for compounding, and synthesizing the food gum-based bacterial cellulose with adjustable and controllable texture characteristics.

The method for preparing the bacterial cellulose comprises the following steps:

s1, adding food gum into a rice bran and rice hull acid hydrolysate fermentation medium, and sterilizing for later use;

s2, inoculating the culture medium obtained in the step S1 into a strain for producing bacterial cellulose, and fermenting at the temperature of 25-35 ℃;

and S3, treating the product fermented in the step S2 by an alkali solution to remove thalli and impurities, so as to obtain the food gum base bacterial cellulose.

Preferably, the food gum is compounded by one or more of xanthan gum, Arabic gum, microcrystalline cellulose, curdlan, chitosan, trehalose, high acyl gellan gum and low acyl gellan gum.

The food gum is added in the step S1 in a single adding or compound adding manner, and when the single adding effect of the food gum is not obvious, the improvement of the bacterial cellulose yield and the regulation and control of the texture characteristics of the food gum can be realized through the synergistic effect of the compound adding of different food gums.

More preferably, the food gum added in step S1 is xanthan gum and curdlan.

More preferably, the food gum added in step S1 is xanthan gum and high acyl gellan gum.

More preferably, the food gum added in step S1 is xanthan gum and low acyl gellan gum.

Preferably, the mass percentage of the food gum in the culture medium is 0.05-0.8%.

Preferably, the strain in step S2 is xylaria foal.

Preferably, the inoculation amount of the strain in the step S2 is 5-15%.

Preferably, the fermentation time in step S2 is 3-15 days.

Preferably, the alkali solution treatment in step S3 is the addition of an aqueous solution of sodium hydroxide or potassium hydroxide.

Preferably, the concentration of the sodium hydroxide or the potassium hydroxide in the step S3 is 0.25-1 mol/L.

Compared with the prior art, the invention has the following beneficial effects:

the invention takes cheap rice processing by-product acid hydrolysis liquid as a fermentation substrate, takes food gum with wide application and high food safety as a fermentation additive, and synthesizes the food gum base bacterial cellulose through fermentation. The addition of the food gum can effectively reduce the inhibiting effect of the acid hydrolysis liquid which is a byproduct in rice processing, improve the yield of the bacterial cellulose and the utilization rate of the fermentation sugar, and can regulate and control the texture characteristics of the bacterial cellulose. The method realizes high-value utilization of rice processing by-products, reduces the waste of rice resources and improves economic benefits. Particularly, the most important innovation of the invention is that when the effect of adding one food gum into the food gum alone is not obvious, the food gum can improve the yield of the bacterial cellulose and regulate and control the texture characteristics through the synergistic effect of the different food gums after being compounded and added.

Detailed Description

The present invention is further illustrated by the following examples, which are not intended to limit the invention in any way. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Unless otherwise indicated, reagents and materials used in the following examples are commercially available.

The following examples were all used: the sugar content of the rice bran acid hydrolysate is 1.25 percent, and the sugar content of the rice bran acid hydrolysate is 1.18 percent; w/v is the proportion of the mass w (g) of the added food gum to the volume v (mL) of the rice bran/rice hull hydrolysate culture medium; v/v is the volume ratio.

Example 1 preparation of bacterial cellulose from Rice Furic acid hydrolysate

The rice bran raw material is hydrolyzed by acid to prepare rice bran acid hydrolysate, and the rice bran acid hydrolysate is adopted to prepare a fermentation medium. Adding 0.1% (w/v) curdlan into a rice bran acid hydrolysate fermentation medium, performing steam sterilization for later use, inoculating 10% (v/v) of curdlan to the colatole bacillus xylosus, culturing at 30 ℃ for 10 days, and treating with 0.5mol/L sodium hydroxide after fermentation to remove thalli and other impurities to obtain a bacterial cellulose product.

Compared with a fermentation culture medium without curdlan under the same conditions, the addition of curdlan improves the yield of bacterial cellulose by 11.2%, the sugar utilization rate by 3.7%, the hardness by 29.9%, the elasticity by 8.4%, the cohesion by 10.8%, the chewiness by 62.7% and the resilience by 2.2%.

Example 2 preparation of bacterial cellulose from Rice Furic acid hydrolysate

The rice bran raw material is hydrolyzed by acid to prepare rice bran acid hydrolysate, and the rice bran acid hydrolysate is adopted to prepare a fermentation medium. Adding 0.1% (w/v) chitosan into a rice bran acid hydrolysate fermentation medium, performing steam sterilization for later use, inoculating the bacterial strain colt with 10% (v/v) of inoculum size, culturing at 30 ℃ for 10 days, and treating with 0.5mol/L sodium hydroxide after fermentation to remove thalli and other impurities to obtain a bacterial cellulose product.

Compared with the fermentation culture medium without adding chitosan under the same condition, the addition of chitosan improves the yield of bacterial cellulose by 10.4 percent, the sugar utilization rate by 5.6 percent and the elasticity by 2.2 percent.

Example 3 preparation of bacterial cellulose from Rice Furic acid hydrolysate

The rice bran raw material is hydrolyzed by acid to prepare rice bran acid hydrolysate, and the rice bran acid hydrolysate is adopted to prepare a fermentation medium. Adding 0.05% (w/v) xanthan gum and 0.05% (w/v) curdlan (the compound ratio is 1: 1) into a fermentation medium of rice furoic acid hydrolysate, performing steam sterilization for later use, inoculating the xylofoal bacillus with the inoculation amount of 10% (v/v), culturing for 10 days at 30 ℃, and removing thalli and other impurities through 0.5mol/L sodium hydroxide treatment after fermentation to obtain a bacterial cellulose product.

Compared with a fermentation culture medium without food gum under the same conditions, the addition of the xanthan gum and the curdlan improves the yield of the bacterial cellulose by 59.8 percent, the sugar utilization rate by 8.3 percent, the hardness by 134.2 percent, the elasticity by 5.6 percent, the cohesion by 0.6 percent, the chewiness by 152.8 percent and the resilience by 17 percent. Bacterial cellulose production was reduced by 21.8% compared to fermentation in medium without addition of food gum with addition of 0.1% (w/v) xanthan gum alone under the same conditions.

Example 4 preparation of bacterial cellulose from Rice Furic acid hydrolysate

The rice bran raw material is hydrolyzed by acid to prepare rice bran acid hydrolysate, and the rice bran acid hydrolysate is adopted to prepare a fermentation medium. Adding 0.05% (w/v) xanthan gum and 0.05% (w/v) high acyl gellan gum (the compound ratio is 1: 1) into a rice bran acid hydrolysate fermentation medium, performing steam sterilization for later use, inoculating the xylose colatorium with the inoculation amount of 10% (v/v), culturing for 10 days at 30 ℃, and removing thalli and other impurities through 0.5mol/L sodium hydroxide treatment after fermentation to obtain a bacterial cellulose product.

Compared with a fermentation culture medium without food gum under the same conditions, the addition of the xanthan gum and the high-acyl gellan gum improves the yield of the bacterial cellulose by 61.4%, the sugar utilization rate by 8.3%, the hardness by 86.7%, the chewiness by 63.2% and the resilience by 4.1%. Compared with fermentation in a culture medium without the addition of the food gum, the yield of the bacterial cellulose is reduced by 12.3 percent when 0.1 percent (w/v) of the high-acyl gellan gum is independently added under the same condition.

Example 5 preparation of bacterial cellulose from Rice Furic acid hydrolysate

The rice bran raw material is hydrolyzed by acid to prepare rice bran acid hydrolysate, and the rice bran acid hydrolysate is adopted to prepare a fermentation medium. Adding 0.05% (w/v) xanthan gum and 0.05% (w/v) arabic gum (the compound ratio is 1: 1) into a fermentation medium of rice furoic acid hydrolysate, performing steam sterilization for later use, inoculating the xylose colatorium autumbergii with the inoculation amount of 10% (v/v), culturing for 10 days at 30 ℃, and removing thalli and other impurities through 0.5mol/L sodium hydroxide treatment after fermentation to obtain a bacterial cellulose product.

Compared with a fermentation culture medium without food gum under the same condition, the addition of the xanthan gum and the arabic gum improves the yield of the bacterial cellulose by 31.2 percent, the sugar utilization rate by 27.8 percent, the hardness by 48.0 percent, the elasticity by 1.7 percent, the chewiness by 46.5 percent and the rebound resilience by 4 percent. Bacterial cellulose production was reduced by 21.8% compared to fermentation in medium without addition of food gum with addition of 0.1% (w/v) xanthan gum alone under the same conditions.

Example 6 preparation of bacterial cellulose from Rice Furic acid hydrolysate

The rice bran raw material is hydrolyzed by acid to prepare rice bran acid hydrolysate, and the rice bran acid hydrolysate is adopted to prepare a fermentation medium. Adding 0.05% (w/v) xanthan gum and 0.05% (w/v) low-acyl gellan gum (the compound ratio is 1: 1) into a rice bran acid hydrolysate fermentation medium, performing steam sterilization for later use, inoculating the Xylobacter colauii with the inoculation amount of 10% (v/v), culturing for 10 days at 30 ℃, and removing thalli and other impurities through 0.5mol/L sodium hydroxide treatment after fermentation to obtain a bacterial cellulose product.

Compared with a fermentation culture medium without food gum under the same conditions, the addition of the xanthan gum and the low-acyl gellan gum improves the yield of the bacterial cellulose by 50.1%, the hardness by 103.6%, the chewiness by 111% and the resilience by 18.4%. Compared with fermentation in a culture medium without the addition of the food gum, the yield of the bacterial cellulose is reduced by 30.9 percent when 0.1 percent (w/v) of the low-acyl gellan gum is added alone under the same conditions.

Example 7 preparation of bacterial cellulose from Rice husk acid hydrolysate

The rice hull acid hydrolysate is prepared by using rice hull materials through acid hydrolysis, and the fermentation medium is prepared by using the rice hull acid hydrolysate. Adding 0.05% (w/v) high acyl gellan gum and 0.05% (w/v) microcrystalline cellulose (the compound ratio is 1: 1) into a rice hull acid hydrolysate fermentation medium, performing steam sterilization for later use, inoculating the xylose colatorium with the inoculation amount of 10% (v/v), culturing for 10 days at 30 ℃, and removing thalli and other impurities through 0.5mol/L sodium hydroxide treatment after fermentation to obtain a bacterial cellulose product.

Compared with a fermentation culture medium without food gum under the same condition, the addition of the high-acyl gellan gum and the microcrystalline cellulose improves the yield of the bacterial cellulose by 38.8 percent, the sugar utilization rate by 14.5 percent, the hardness by 2.7 percent, the elasticity by 2.2 percent, the cohesion by 3.5 percent and the chewiness by 10.1 percent. Compared with fermentation in which 0.1% (w/v) of high acyl gellan gum is added alone under the same conditions, the compound addition increases the bacterial cellulose yield by 65.1%, the sugar utilization rate by 2.5%, the elasticity by 3.4%, and the cohesion by 2.9%.

EXAMPLE 8 preparation of bacterial cellulose from Rice husk acid hydrolysate

The rice hull acid hydrolysate is prepared by using rice hull materials through acid hydrolysis, and the fermentation medium is prepared by using the rice hull acid hydrolysate. Adding 0.05% (w/v) high acyl gellan gum and 0.05% (w/v) Arabic gum (the compound ratio is 1: 1) into a rice hull acid hydrolysate fermentation medium, performing steam sterilization for later use, inoculating the xylose colatorium with the inoculation amount of 10% (v/v), culturing for 10 days at 30 ℃, and removing thalli and other impurities through 0.5mol/L sodium hydroxide treatment after fermentation to obtain a bacterial cellulose product.

Compared with a fermentation culture medium without food gum under the same condition, the addition of the high-acyl gellan gum and the Arabic gum improves the yield of the bacterial cellulose by 30.1 percent, the hardness by 34.1 percent, the elasticity by 2.2 percent, the cohesion by 1.6 percent and the chewiness by 39.9 percent. Compared with fermentation in which 0.1% (w/v) of high acyl gellan gum is added alone under the same conditions, the compound addition increases the yield of bacterial cellulose by 54.8%, the elasticity by 3.4%, and the chewiness by 4.3%.

According to the embodiments, the food gum is added into the fermentation culture medium of the rice bran or the rice bran acid hydrolysate alone or in a compounding way, so that the yield of the prepared bacterial cellulose can be improved, and the texture characteristics of the bacterial cellulose can be regulated and controlled; however, the effect of adding one food gum alone is not obvious, and even the yield of bacterial cellulose is reduced, and the problem can be solved by adding a plurality of food gums in a compounding manner. The curdlan is independently added in the embodiment 1, so that the yield of the bacterial cellulose is improved by 11.2 percent; in examples 3 to 6, when the yield of the compound addition is compared, it is found that the bacterial cellulose yield is reduced by 21.8%, 12.3% or 30.9% by adding the xanthan gum, the high acyl gellan gum or the low acyl gellan gum alone compared with the fermentation medium without the food gum; xanthan and curdlan 1 were used in example 3: 1, the yield of the bacterial cellulose is improved by 59.8 percent after the compound is compounded, and the yield of the bacterial cellulose prepared by adopting the compound added food gum can be improved to 61.4 percent to the maximum. Therefore, the compound added food gum has a synergistic effect, and the situation that the effect is not obvious and the yield of the bacterial cellulose is reduced can be caused by singly adding a certain gum, but the problem can be solved after the compound addition, and the yield is improved.

In summary, different types of food gums are added into the rice bran and the rice hull acid hydrolysate, and particularly different food gums are added for compounding, so that the synergistic effect is achieved, the inhibition of the fermentation environment can be overcome, the yield and the sugar utilization rate are improved, and the fermentation delay period is shortened; but also can realize the improvement of the output of the bacterial cellulose and the regulation and control of the texture characteristics by the food gum.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.