阅读说明：本技术 一种冷藏期具有高抗氧化活性的合生元发酵乳及其制备方法 (Synbiotic fermented milk with high antioxidant activity in cold storage period and preparation method thereof ) 是由 张志鸿 魏华 张娜 李一娟 孟迎平 陶雪莹 何丽华 于 2021-08-18 设计创作，主要内容包括：本发明公开了一种冷藏期具有高抗氧化活性的合生元发酵乳及其制备方法,本发明在植物乳杆菌ZDY2013发酵乳粉的基础上,通过添加低聚木糖和低聚异麦芽糖组合物获得。本发明制得的冷藏期具有高抗氧化活性的合生元发酵乳,以DPPH自由基、ABTS自由基、OH自由基清除能力评价,所得功能低聚糖发酵乳相比葡萄糖发酵乳在冷藏期具有更优的抗氧化活性。本发明的制备方法操作简便、成本较低,满足规模化生产的工艺要求,具有推广潜力。(The invention discloses synbiotic fermented milk with high antioxidant activity in a cold storage period and a preparation method thereof, and the synbiotic fermented milk is obtained by adding a xylooligosaccharide and isomaltooligosaccharide composition on the basis of lactobacillus plantarum ZDY2013 fermented milk powder. The synbiotic fermented milk with high antioxidant activity in the cold storage period is evaluated by DPPH free radical, ABTS free radical and OH free radical scavenging capacity, and compared with glucose fermented milk, the obtained functional oligosaccharide fermented milk has better antioxidant activity in the cold storage period. The preparation method is simple and convenient to operate, has low cost, meets the process requirements of large-scale production, and has popularization potential.)

1. The synbiotic fermented milk with high antioxidant activity in the cold storage period is characterized by comprising functional oligosaccharides, lactobacillus plantarum ZDY2013 and water as raw materials, wherein the lactobacillus plantarum ZDY2013 is preserved in China center for type culture collection (CCTCC NO): and M2014170.

2. The synbiotic fermented milk according to claim 1, characterized in that the raw materials comprise, in parts by weight: 6-12 parts of functional oligosaccharide, 2-5 parts of lactobacillus plantarum ZDY2013 powder and 40-60 parts of water.

3. The synbiotic fermented milk according to claim 2, characterized in that its raw materials further comprise 0.1-0.4 parts of a food stabilizer.

4. The synbiotic fermented milk according to claim 3, characterized in that the food stabilizer is at least one of sodium carboxymethyl cellulose and pectin.

5. The synbiotic fermented milk according to claim 2, wherein the lactobacillus plantarum ZDY2013 powder is obtained by subjecting a fermentation broth of the lactobacillus plantarum ZDY2013 to solid-liquid separation, leaving a precipitate, and then resuspending the precipitate with skim milk.

6. The synbiotic fermented milk according to claim 1, characterized in that the functional oligosaccharide is a mixture of xylo-oligosaccharide and isomalto-oligosaccharide.

7. The synbiotic fermented milk according to claim 6, wherein the mass ratio of xylooligosaccharide to isomaltooligosaccharide is 1: 1.

8. A preparation method of synbiotic fermented milk with high antioxidant activity in a refrigeration period is characterized by comprising the following steps:

crushing 6-12 parts by weight of functional oligosaccharide, mixing with 2-5 parts by weight of lactobacillus plantarum ZDY2013 powder and 40-60 parts by weight of water for 40-60 minutes, and carrying out anaerobic fermentation for 12-24 hours to obtain synbiotics fermented milk; the functional oligosaccharide is obtained by mixing xylooligosaccharide and isomaltooligosaccharide according to the mass ratio of 1: 1.

9. The preparation method of claim 8, wherein the preparation of the lactobacillus plantarum ZDY2013 powder comprises the following steps: carrying out solid-liquid separation on the fermentation liquor of the lactobacillus plantarum ZDY2013, leaving a precipitate, adding 30% skimmed milk in an amount which is 5 times the mass of the precipitate for resuspension, freezing and then carrying out vacuum drying.

Technical Field

The invention belongs to the technical field of dairy product production, and particularly relates to synbiotic fermented milk with high antioxidant activity in a refrigeration period and a preparation method thereof.

Background

The lactobacillus fermented milk is a milk product which can retain milk protein components and provide probiotic metabolism functional substances, is rich in nutrition and easy to absorb, and has important effects on human flora balance and intestinal health. At present, lactic acid bacteria fermented milk which is popular in the market is generally prepared by fermenting streptococcus thermophilus, lactobacillus bulgaricus, bifidobacterium animalis Bb-12, lactobacillus acidophilus NCFMs and the like which are taken as fermenting agents, and the strains belong to foreign research institutions or enterprises. Therefore, the method has important strategic significance in implementing industrialized application by utilizing the strains with intellectual property rights in China.

The functional oligosaccharide is carbohydrate as prebiotics, can not be digested and absorbed, directly enters the intestinal tract for the metabolism of lactic acid bacteria, and promotes the health of human bodies. Antioxidant activity refers to the ability to eliminate oxygen free radicals in the human body. Research shows that excessive oxidative metabolism in vivo can cause direct and slow damage to cells, accelerate the aging of the organism and even cause related diseases. Therefore, the intake of the food with antioxidant activity is helpful for relieving the oxygen free radical content in vivo, and is very beneficial to the health of human body.

In the prior art, substances with stronger antioxidant activity are generally accepted to comprise blueberry extract, tea extract containing tea polyphenol, coenzyme Q10, medlar extract and the like. The production period of the product is long, and the links of planting, processing and the like are complex, so that the cost of the product in the prior art is high. Different from plant products, the fermentation of the microorganisms is not limited by regions and spaces, in addition, the production efficiency is high, the products are easy to harvest, and the large-scale production process is convenient for standardization. Therefore, the synbiotic fermented milk with high antioxidant activity in the cold storage period is developed, a new choice is provided for consumers, and meanwhile, the production cost can be obviously reduced.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides synbiotic fermented milk with high antioxidant activity in a cold storage period and a preparation method thereof, and the preparation method specifically adopts the following technical scheme:

a synbiotic fermented milk with high antioxidant activity in the cold storage period comprises functional oligosaccharides, Lactobacillus plantarum Z DY2013 and water, wherein the Lactobacillus plantarum ZDY2013 is preserved in China center for type culture Collection in 4-28 th 2014, with the addresses: wuhan university in Wuhan, China, which is abbreviated as C CTCC, and the preservation number is CCTCC NO: and M2014170.

Preferably, the raw materials comprise the following components in parts by weight: 6-12 parts of functional oligosaccharide, 2-5 parts of lactobacillus plantarum ZDY2013 powder and 40-60 parts of water.

Preferably, the raw materials also comprise 0.1-0.4 part of food stabilizer.

Preferably, the food stabilizer is at least one of sodium carboxymethyl cellulose and pectin.

Preferably, the lactobacillus plantarum ZDY2013 powder is obtained by performing solid-liquid separation on fermentation liquor of the lactobacillus plantarum ZDY2013, leaving a precipitate, and then resuspending the precipitate by using skim milk.

Preferably, the functional oligosaccharide is a mixture of xylooligosaccharide and isomaltooligosaccharide.

Preferably, the mass ratio of the xylooligosaccharide to the isomaltooligosaccharide is 1:1, so that the anti-oxidation effect can be better exerted.

The invention also provides a preparation method of the synbiotic fermented milk with high antioxidant activity in the cold storage period, which comprises the following steps:

crushing 6-12 parts by weight of functional oligosaccharide, mixing with 2-5 parts by weight of lactobacillus plantarum ZDY2013 powder and 40-60 parts by weight of water for 40-60 minutes, and carrying out anaerobic fermentation for 12-24 hours to obtain synbiotics fermented milk; the functional oligosaccharide is obtained by mixing xylooligosaccharide and isomaltooligosaccharide according to the mass ratio of 1: 1.

Preferably, the preparation of the lactobacillus plantarum ZDY2013 powder comprises the following steps: carrying out solid-liquid separation on the fermentation liquor of the lactobacillus plantarum ZDY2013, leaving a precipitate, adding 30% skimmed milk in an amount which is 5 times the mass of the precipitate for resuspension, freezing and then carrying out vacuum drying.

The invention has the beneficial effects that: on the basis of lactobacillus plantarum fermented milk powder, the xylose oligosaccharide and isomaltose oligosaccharide composition with prebiotics characteristics is added, and the bacteria powder has better antioxidant activity in a refrigeration period according to evaluation of DPPH free radical, ABTS free radical and OH free radical scavenging capacity. The preparation method provided by the invention has wider applicability to various lactic acid bacteria with carbohydrate metabolizing enzymes. The functional oligosaccharide can promote the propagation and metabolism of lactobacillus plantarum ZDY2013 to generate special flavor substances, can reduce the pH value of synbiotic fermented milk through acid production, thereby inhibiting the growth of intestinal pathogenic bacteria, improving the shelf life of fermented food, and has multiple effects of regulating the body immunocompetence, reducing the blood sugar concentration and the like.

When the functional oligosaccharide is used as a compound formula component, the synbiotic fermented milk has better water binding capacity and strong antioxidant capacity with lactobacillus plantarum ZDY2013, and especially when the mass volume ratio of the xylooligosaccharide and isomaltooligosaccharide composition in the synbiotic fermented milk is 1.5%, the antioxidant activity effect of the synbiotic fermented milk is optimal.

Aiming at the problem that the activity cold storage period of lactobacillus plantarum in a similar category is difficult to maintain in the fermented milk product, the invention further preferably selects the addition proportion of the functional oligosaccharide composition which is suitable for the lactobacillus plantarum to keep high activity in the fermented milk product, and the composition has simple components, clear structure and outstanding prebiotics property. In addition, the lactobacillus plantarum functional synbiotic fermented milk prepared by adding the oligosaccharide composition has strong water retention, long shelf life and good flavor. The preparation method is relatively simple and convenient to operate, has low cost, meets the process requirements of large-scale production, and has great popularization potential.

Drawings

FIG. 1 is a graph showing the results of the number of viable bacteria and pH value changes of Lactobacillus plantarum ZDY2013 fermented by functional oligosaccharides in example 1 of the present invention;

FIG. 2 is a graph showing the result of determination of DPPH free radical scavenging rate in Lactobacillus plantarum synbiotic fermented milk in the cold storage period in example 3 of the present invention;

FIG. 3 is a graph showing the results of ABTS free radical scavenging assay of Lactobacillus plantarum synbiotic fermented milk in the cold storage period in example 4 of the present invention;

FIG. 4 is a graph showing the results of measuring the OH free radical scavenging rate of Lactobacillus plantarum synbiotic fermented milk in the cold storage period in example 5 of the present invention.

Detailed Description

The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments and the accompanying drawings to fully understand the objects, aspects and effects of the present invention.

Example 1

Taking out the frozen strain from a refrigerator at minus 80 ℃, streaking the strain into an MRS plate by using an inoculating loop, performing static culture at 37 ℃ for 36h, taking the activated single colony, inoculating the single colony into 5mL of MRS broth culture medium, and performing static culture at 37 ℃ for 12 h. Subculturing twice, and the inoculum size is 1%. Inoculating the activated Lactobacillus plantarum ZDY2013 into 4mL of sugar-free MRS culture medium, adding 1mL of functional oligosaccharide solution to make the final concentration 1.5% (mass to volume ratio), carrying out anaerobic culture for 24h, and determining the OD of the fermentation liquor every 3h₆₀₀The value and the pH value, and the influence of the added functional oligosaccharide on the viable count of the lactobacillus plantarum ZDY2013 and the pH value of the fermentation liquor are analyzed and shown in figure 1.

Example 2

A preparation method of synbiotic fermented milk with high antioxidant activity in a refrigeration period comprises the following steps:

(1) fully crushing 6g of xylo-oligosaccharide and 6g of isomalto-oligosaccharide in a crusher, and sieving with a 100-mesh sieve to obtain ingredient powder;

(2) carrying out solid-liquid separation on the fermentation liquor of the lactobacillus plantarum ZDY2013, leaving 5g of precipitate, adding 25g of 30% skim milk for resuspending the precipitate, freezing and then carrying out vacuum drying to prepare lactobacillus plantarum ZDY2013 bacterial powder;

(3) mixing Lactobacillus plantarum ZDY2013 powder, adjuvant powder and 0.4g pectin, adding 60g water, mixing for 40min, fermenting for 12h to obtain synbiotic fermented milk, and refrigerating at 2-6 deg.C for 1 year.

The viable count content, pH value and water holding capacity of the prepared synbiotic fermented milk with high antioxidant activity in the refrigeration period are respectively measured on days 1, 7, 14 and 21, and are shown in table 1.

Wherein the water holding capacity test process of the synbiotic fermented milk comprises the following steps: weighing an empty 5mL centrifuge tube, and recording the mass as W₀2.5mL of synbiotic fermented milk prepared in example 2 was added, and the mass was W₁. Centrifuging at 3000r/min and 4 deg.C for 10 min. Discarding the supernatant, weighing and recording the weight as W₂The assay was performed 3 times in parallel. The water holding capacity calculation formula is as follows: water holding capacity (%) (% water holding capacity) x 100 water holding capacity (%) (W)₂-W₁)/(W₁-W_o)×100％。

TABLE 1

Example 3

Measuring the DPPH free radical scavenging capacity of synbiotic fermented milk in the cold storage period:

the synbiotic fermented milk prepared in example 2 was centrifuged at 8000r/min for 10min, and then filtered through a 0.44 μm filter to obtain whey; a1.5 mL of the PPH solution (0.2mmol/L, 95% methanol as solvent) was mixed with 0.5mL of whey sample or 95% methanol (control) and reacted at room temperature for 30 min. Centrifuging at 8000r/min at 4 deg.C for 10min, collecting supernatant, and measuring absorbance at 517 nm. The DPPH radical clearance calculation formula is as follows:

clearance (%) ═ a₀-A₁)/A₀X 100% of formula (II) A₀Denotes the absorbance in the presence of 95% methanol (control), A₁The absorbance of the whey sample was shown and the results are shown in FIG. 2.

Example 4

Determining the free radical scavenging capacity of synbiotic fermented milk ABTS in the refrigeration period:

ABTS solution was first diluted with 95% ethanol solution to OD734 ═ 0.700 ± 0.020 (a)₀). mu.L of synbiotic fermented milk prepared in example 2 was mixed with 3mL of the aqueous solution of LABTS, shaken, reacted in the dark for 30min, and then the absorbance A was measured at 734nm₁By adding 150. mu.LThe ethanol solution is used as a blank control instead of the sample, and the absorbance is A₀Each sample was assayed in 3 replicates. The ABTS cation radical scavenging ability calculation formula is as follows:

clearance (%) ═ a₀-A₁)/A₀×100％

In the formula: a. the₀ABTS absorbance for no added sample; a. the₁The absorbance of the samples after the reaction was added, and the measurement results are shown in FIG. 3.

Example 5

Measuring the OH free radical scavenging capacity of synbiotic fermented milk in the cold storage period:

first, synbiotic fermented milk prepared in example 2, 2.5mmol/L o-phenanthroline solution, 0.02mol/L PBS (pH 7.4) and distilled water were mixed in equal volume, and after mixing uniformly, the equal volume of 2.5mmol/L FeSO was added₄Solution and 20mmol/L H₂O₂The solution is fully mixed and then is bathed in constant temperature water at 37 ℃ for 1 h. The test substance's ability to scavenge OH radicals is judged by the change in absorbance at 536 nm. The OH radical clearance is calculated as follows:

clearance (%) ═ a_a-A₁)/(A_b-A₁) X 100%, wherein: aa is the absorbance of synbiotic fermented whey instead of distilled water; a. the₁The absorbance of the mixed solution; a. the_bTo substitute distilled water for H₂O₂The absorbance of the solution was measured, and the measurement results are shown in FIG. 4.

While the present invention has been described in considerable detail and with particular reference to a few illustrative embodiments thereof, it is not intended to be limited to any such details or embodiments or any particular embodiments, but it is to be construed as effectively covering the intended scope of the invention by providing a broad, potential interpretation of such claims in view of the prior art with reference to the appended claims. Furthermore, the foregoing describes the invention in terms of embodiments foreseen by the inventor for which an enabling description was available, notwithstanding that insubstantial modifications of the invention, not presently foreseen, may nonetheless represent equivalent modifications thereto.