CN111096403A

CN111096403A - Preparation method of nutritional type compound lactobacillus fermented tomato juice

Info

Publication number: CN111096403A
Application number: CN201911369476.1A
Authority: CN
Inventors: 刘中海; 王陈强; 马自强; 沈广军; 施晓艳; 程志斌; 李静; 楚勇
Original assignee: Xinjiang Guannong Fruit Antler Co Ltd
Current assignee: Xinjiang Guannong Fruit Antler Co Ltd
Priority date: 2019-12-26
Filing date: 2019-12-26
Publication date: 2020-05-05

Abstract

The invention discloses a preparation method of nutritional compound lactobacillus fermented tomato juice, which comprises the following steps: checking and accepting raw materials, cleaning raw materials, grading, selecting, crushing, preheating for enzyme deactivation, pulping, centrifuging, blending, sterilizing, preparing a lactic acid bacteria starter, inoculating, fermenting, blending for the second time, homogenizing, degassing, sterilizing for the second time, and canning. The tomato juice beverage has the beneficial effects that the tomato juice beverage is rich in nutrition, low-temperature preheating enzyme deactivation and high-temperature instantaneous sterilization are adopted, so that tomatoes fully react with oxygen to form more substances with characteristic flavor, the taste is better, and the nutrient substances in the tomato juice are reserved to the greatest extent; meanwhile, the tomato juice has a certain effect of reducing blood sugar, various amino acids, flavor substances and extracellular polysaccharide are formed in the fermentation process, the obtained fermented tomato juice is rich in nutrition, the product stability is enhanced due to the production of the extracellular polysaccharide, and the defect that the stability of the tomato juice is insufficient due to low-temperature preheating enzyme deactivation is overcome.

Description

Preparation method of nutritional type compound lactobacillus fermented tomato juice

Technical Field

The invention relates to the technical field of preparation of fermented fruit and vegetable juice, in particular to a preparation method of nutritional type compound lactobacillus fermented tomato juice.

Background

Tomato is a herbaceous plant of the family Solanaceae, also known as tomato or Juniperus persimmon. Is one of vegetable crops which are generally planted in the world. The tomato is planted in large quantities all over China at present, contains rich nutrient components (every 100g of tomato contains 2.2g of sugar, 10.03mg of vitamin B, 20.02mg of vitamin B, 0.6mg of nicotinic acid, 11mg of vitamin C11mg, 0.31mg of carotene, 8mg of calcium, 37mg of phosphorus and 0.4mg of iron) and contains more organic acids such as citric acid and malic acid, particularly the content of nicotinic acid is several seconds in fruits and vegetables.

The vitamin C contained in the food is not easy to be destroyed by cooking. The tomato is rich in lycopene, and has the functions of delaying senility, preventing cardiovascular diseases, enhancing the immunity of the organism, preventing and resisting cancers and the like. According to calculation, each person can eat about 300 g of tomatoes every day, and the requirements for vitamins and inorganic salt can be met.

In the prior art, the research and development of lactobacillus fermentation products are carried out by using sweeteners such as tomato juice, sauce, white sugar, sucralose and the like, but high-temperature treatment is mostly used in the process, so that the taste of the tomato juice is reduced, the nutrient components of the fermented juice are lost, the refreshing taste of the tomato juice is not reserved, the use of the white sugar is not in accordance with the health concept of modern people, and the problems need to be improved urgently.

Disclosure of Invention

The invention aims to solve the problems and designs a preparation method of nutritional compound lactobacillus fermented tomato juice.

The technical scheme of the invention is that the preparation method of the nutritional type compound lactobacillus fermented tomato juice comprises the following steps:

step one, checking and accepting raw materials: selecting fresh tomatoes with proper maturity, bright red color, no insect pest and high soluble solid content as raw materials, wherein the proper maturity is generally selected to be ripe tomatoes with hard and full fruits;

step two, cleaning raw materials: cleaning tomatoes by adopting five-grade water, and then primarily disinfecting by adopting subacid electrolyzed water and removing silt;

step three, grading, namely removing the green and yellow fruits in the raw materials by adopting a water buoyancy grading method according to the density relation of the raw materials, and placing the tomatoes into water to stratify the green and yellow fruits of the tomatoes and the ripe tomatoes in the water under the action of water buoyancy after the tomatoes are placed into the water because the densities of the immature green and yellow fruits of the tomatoes and the ripe tomatoes are different, so that the green and yellow fruits in the raw materials are removed;

selecting, namely selecting the raw materials, and removing unqualified fruits such as rotten fruits, cracked black spot fruits, worm eaten fruits and the like in the raw materials;

crushing, namely crushing the sorted tomato raw materials by using a crushing pump and conveying the crushed tomato raw materials to a preheating storage tank;

step six, preheating and enzyme deactivation, namely slowly heating the raw materials in the preheating storage tank to 35-40 ℃ in an air-introducing environment, then keeping for 10min, and quickly raising the temperature to 65 ℃ for preheating and enzyme deactivation;

step seven, inputting the preheated enzyme-deactivated raw materials into a beater for beating treatment, wherein a sieve of the beater adopts a sieve with the size of 0.6-1.0mm, and tomato skin and seeds are removed through beating treatment to obtain tomato juice;

step eight, inputting the pulped tomato juice into a horizontal screw centrifuge, and adjusting the feeding speed of the tomato juice and the rotating speed of the centrifuge according to the ripeness degree, the preheating temperature and the preheating time of tomatoes to ensure that a proper amount of cellulose and pectin are reserved in the tomato juice and the stability of the tomato juice is ensured;

step nine, blending, namely adding apple fructose with the sweetness of 75Brix and pear fructose with the sweetness of 75Brix into the tomato juice after centrifugal treatment, fully dissolving the apple fructose and the pear fructose and uniformly mixing the apple fructose and the pear fructose into the tomato juice, wherein the Brix represents the sweetness;

step ten, sterilizing, namely performing pasteurization on the blended tomato juice, and then cooling to 40 ℃;

eleven, preparing a lactic acid bacteria starter, separating strains from local yogurt of Yanqi in Xinjiang to perform a fermentation experiment, obtaining two strains with better activity, and identifying the strains as lactobacillus plantarum and streptococcus thermophilus; respectively inoculating strains into triangular flasks containing 100ml of skim milk, wherein the inoculation amount is 0.1g/L, and activating at 37 ℃ for 15h to obtain two lactic acid bacteria leavens;

step twelve, inoculating, namely inoculating the two activated lactobacillus leavening agents into the cooled tomato juice in the step ten according to the inoculation amount of 2%, and fermenting at 37 ℃ for 12-18h to obtain fermented juice;

thirteen, fermenting, when the pH of the fermented juice is between 3.85 and 4.05,combined sensory evaluationDetermining the fermentation end point of the fermentation juice; the sensory evaluation means that the fermented juice is sour, sweet and palatable, and the tissue morphology has no obvious layered water separation phenomenon.

And (3) determining the fermentation end point of the fermented tomato juice, carrying out sensory evaluation, wherein the evaluation standard is shown in table 6, and determining the optimal formula of the tomato juice beverage by taking the sensory evaluation as the final evaluation standard.

TABLE 6

Fourteen, homogenizing, namely inputting the fermented tomato juice into a homogenizer, refining pulp and fiber components through the homogenizer, and enhancing the stability;

step fifteen, degassing, namely degassing the homogenized tomato juice by adopting a vacuumizing and degassing technology, wherein the degassing pressure is 0.06-0.08 MPA;

sixthly, secondary sterilization, namely performing sterilization on the degassed tomato juice by using a UHT sterilization process, wherein the sterilization temperature is 115 ℃, and the sterilization time is 15 s;

seventhly, aseptic canning is carried out on the juice after the secondary sterilization.

In the first step, the soluble solid content of the tomatoes is 4.5-6.0.

In the sixth step, the temperature of the raw materials in the preheating storage tank is slowly raised to 40 ℃, and then the temperature is kept for 10 min.

And in the seventh step, the screen of the beater adopts a screen with the aperture of 0.6 mm.

And C, after the fermentation process in the step III is finished, adding L-arabinose, tea polyphenol, citric acid, VC and the like according to production needs, and performing secondary blending, wherein the tea polyphenol, the citric acid and the VC are not added.

In the step eight, the feeding speed of the tomato juice is 2.3-4.6L/s; the centrifugal rotating speed is 1400-2000 r/min.

In the ninth step, 5% -8% of apple fructose (mass percentage of apple fructose to the centrifuged tomato juice) is added, and 8% -10% of bergamot pear fructose (mass percentage of bergamot pear fructose to the centrifuged tomato juice) is added.

In the eleventh step, the concentration of the skim milk is 13%.

In the seventeenth step, the shelf life of the aseptically filled tomato juice is 18 months.

Advantageous effects

The tomato fermented juice product prepared by the technical scheme of the invention contains a large amount of physiologically active substances such as vitamins and minerals and nutrient substances such as saccharides, amino acids and dietary fibers, and has the functions of regulating blood sugar, regulating intestinal flora, promoting digestion, reducing fat and cholesterol, softening blood vessels, lowering blood pressure, eliminating fatigue, beautifying and protecting skin, delaying senility and the like;

in addition, the invention adopts low-temperature preheating for enzyme deactivation and high-temperature instant sterilization, so that the tomatoes fully react with oxygen to form more substances with characteristic flavor, the taste is better, and the nutrient substances in the tomato juice are also retained to the greatest extent.

Meanwhile, bergamot pear fructose and apple fructose are used as fermentation exogenous sugars, and L-arabinose is added as prebiotics, so that the special flavor of the fermented tomato juice is increased to a certain extent, and the tomato juice has a certain effect of reducing blood sugar.

And various amino acids, flavor substances and extracellular polysaccharide are formed in the fermentation process, the obtained fermented tomato juice is rich in nutrition, the product stability is enhanced by the production of the extracellular polysaccharide, and the defect of insufficient stability of the tomato juice inactivated by low-temperature preheating is overcome.

Compared with the similar products sold in the market, the fermented tomato juice provided by the invention has higher sweetness, viscosity and consistency and is more exquisite and mellow in taste.

The protein and hydrolysate small peptide and amino acid thereof have important contribution to the nutritional quality and flavor of tomato juice. The protein content of the obtained product is 1.0g/100g, which is much higher than that of common fruit juice beverage and is close to that of most of vegetable protein beverage sold in the market; the content of each essential amino acid and the total amount of the amino acid are higher than those of the similar products sold in the market, wherein the total amount of the amino acid in the products is 426mg/100g, which is about 1.3 times of that of the similar products sold in the market.

In terms of vitamin content, the vitamin B2 content in the product is rich and is 1.68 times of that of the similar product sold in the market. The content of the vitamin C is 2.16mg/100g which is lower than that of the similar products sold in the market, but the content of the vitamin B1 is 0.0316mg/100g which is close to that of the similar products sold in the market.

In the aspect of natural pigment content, the carotene content in the product is 64.4ug/100g, which is close to 3 times of the content of the similar products sold in the market. Lycopene is the main element pigment of mature tomato, and has multiple effects of resisting oxidation, reducing blood lipid and cardiovascular disease risk, inhibiting tumor, and improving organism immunity. The content of the lycopene in the product is 69.4mg/1000g, which is slightly higher than that of similar products sold in the market, the chromaticity detection result and the sensory effect are integrated, and the level of the lycopene in the product is substantially equivalent to that of the similar products sold in the market.

The tomato juice contains abundant trace elements, and has important effect on human health. The Ca content (86.4mg/kg) and the K content (1.24 multiplied by 103mg/kg) are both higher than those of the similar products sold on the market, and the Zn content (1.42mg/kg) and the Fe content (2.96mg/kg) are slightly lower than those of the similar products sold on the market.

Pectin and vitamins are important components of dietary fiber, and contribute to improving gastrointestinal function and enhancing satiety. The product is rich in pectin and cellulose. According to results, the pectin content is 3.12g/kg, the dietary fiber content is 0.328g/100g, and the pectin content and the dietary fiber content are higher than those of similar products and common fruit juice beverages sold in the market, and the improvement of the dietary fiber increases the stability of the products and reduces layering; on the other hand, the product is endowed with thick mouthfeel.

The content of the total acid is closely related to the sensory quality of the product, and the evaluation of the taster on the acidity of the product is directly influenced. The total acid content of the product is 9.12g/kg, which is slightly higher than that of the similar products sold in the market, and the detection value is consistent with the sensory evaluation result. The organic acid in the tomato juice has multiple health-care effects of protecting vitamin C, softening blood vessels, promoting absorption of calcium and iron elements and the like, so the common organic acid in the three plant raw materials of citric acid, malic acid and tartaric acid is selected for further analysis in experiments. The citric acid content is 3.6g/kg, which is 1.2 times of the same kind of products sold in the market; the malic acid content is 2.8g/kg, which is 1.1 times of the similar products sold in the market; tartaric acid was not detected in any of the samples.

The experiment carried out quantitative detection on fatty acid. The detected result is lower than the detection limit of an instrument and a method, the fat content is 0.0g/100g, and the result is consistent with the fat content and the label identification result of a commercial product. The nutritional value of unsaturated fatty acids and the risk of oxidative deterioration during storage are taken into account, and the influence of fat can be disregarded.

Drawings

FIG. 1 is a schematic flow chart of a preparation method of a nutritional type compound lactobacillus fermented tomato juice according to the invention;

FIG. 2 is a standard map of mixed fatty acids according to the present invention;

FIG. 3 is a standard chromatogram of a mixture of amino acids according to the invention;

FIG. 4 is a chromatogram of an amino acid sample of Guannong fermented tomato juice according to the present invention;

FIG. 5 is a chromatogram of an amino acid sample from a commercial tomato juice according to the present invention;

FIG. 6 is a graph comparing the amino acid content of two tomato juices according to the invention;

FIG. 7 is a standard sample chromatogram of vitamin B1 according to the present invention;

FIG. 8 is a chromatogram of a sample of Guannong fermented tomato juice vitamin B1;

FIG. 9 is a sample chromatogram of vitamin B1 from a commercial tomato juice according to the present invention;

FIG. 10 is a standard sample chromatogram of vitamin B2 according to the present invention;

FIG. 11 is a chromatogram of a sample of Guannong fermented tomato juice vitamin B2 according to the present invention;

FIG. 12 is a sample chromatogram of vitamin B2 from a commercial tomato juice according to the present invention;

FIG. 13 is a standard sample chromatogram of β -carotene according to the invention;

FIG. 14 is a chromatogram of Guannong fermented tomato juice β -carotene sample according to the present invention;

FIG. 15 is a chromatogram of a commercial tomato juice β -carotene sample according to the invention;

FIG. 16 is a standard sample chromatogram of lycopene according to the present invention;

FIG. 17 is a chromatogram of a sample of Guannong fermented tomato juice lycopene according to the present invention;

FIG. 18 is a sample chromatogram of a commercial tomato juice lycopene according to the present invention;

FIG. 19 is a graph showing the standard curve of Ca element according to the present invention;

FIG. 20 is a standard curve diagram of Zn element according to the present invention;

FIG. 21 is a standard curve of Fe according to the present invention;

FIG. 22 is a standard curve of K elements according to the present invention;

FIG. 23 is a chromatogram of an organic acid standard according to the present invention;

FIG. 24 is a chromatogram of organic acid from Guannong fermented tomato juice according to the present invention;

fig. 25 is a chromatogram of organic acid from commercial tomato juice according to the present invention;

FIG. 26 is a color difference plot of two tomato samples according to the present invention;

table 1 shows the amino acid content in Guannong fermented tomato juice according to the invention (unit: mg/100 g);

table 2 shows the amino acid content in the commercially available tomato juice of the present invention (unit: mg/100 g);

table 3 shows the contents of trace elements in the two tomato juices (unit: mg/kg);

table 4 is the content of organic acids in the two tomato juices according to the invention (unit: g/kg);

table 5 is a table of colour analysis of two tomato juices according to the invention;

table 6 is a table of sensory evaluation criteria for the fermented juices of the present invention.

Detailed Description

The invention is described in detail with reference to the accompanying drawings, as shown in fig. 1-26, the invention is characterized in that the sorted raw materials are crushed by a crushing pump and conveyed to a preheating storage tank, the temperature of the raw materials in the preheating storage tank is slowly raised to 35-40 ℃ in an air-introducing environment, then is kept for 10min, and then is rapidly raised to 65 ℃ for preheating and enzyme deactivation; inputting the preheated and enzyme-deactivated raw materials into a beater for beating, wherein a sieve of the beater adopts a sieve of 0.6-1.0mm, tomato peel and seeds are removed through beating to obtain tomato juice, the beaten tomato juice is input into a horizontal screw centrifuge, the feeding speed and the centrifuge rotating speed of the tomato juice are adjusted according to the tomato maturity, the preheating temperature and the preheating time, a proper amount of cellulose and pectin are kept in the tomato juice, the stability of the tomato juice is ensured, 75Brix apple fructose is added into the centrifuged tomato juice, 75Brix bergamot fructose is added to be fully dissolved and uniformly mixed into the tomato juice, pasteurization is carried out on the blended tomato juice, and then the tomato juice is cooled to 40 ℃. Separating strains from local yogurt of Yanqi Yan Xinjiang, performing fermentation experiments to obtain two strains with better activity, and identifying the strains as lactobacillus plantarum and streptococcus thermophilus; respectively inoculating strains into triangular flasks containing 100ml of skim milk, wherein the inoculation amount is 0.1g/L, and activating at 37 ℃ for 15h to obtain two lactic acid bacteria leavens; inoculating the two activated lactobacillus leavening agents into the cooled tomato juice according to the inoculation amount of 2%, respectively, fermenting at 37 ℃ for 12-18h to obtain fermented juice, and determining the fermentation end point of the fermented juice by combining sensory evaluation when the pH of the fermented juice is 3.85-4.05.

Fructose is one of the most common ketohexoses. Is present in honey and fruits, and is combined with glucose to form sucrose for daily use. Fructose, which contains 6 carbon atoms and is also a monosaccharide, is an isomer of glucose, and is present in large amounts in the free state in fruit juices and honey, and can also combine with glucose to form sucrose. Pure fructose is a colorless crystal with a melting point of 103-105 ℃, is not easy to crystallize, is usually a viscous liquid, and is easily soluble in water, ethanol and diethyl ether.

The fructose used in the invention is extracted from fruits, is natural and has rich sweet taste, and is not easy to cause hyperglycemia, fat accumulation and fatness, and decayed teeth, so that the fructose is known by more people. The fructose is mainly produced from natural fruits and grains, and has the advantages of good taste, high sweetness, low glycemic index, difficult dental caries, and the like. The sweetness of fructose is 1.8 times that of sucrose and is the highest sugar in all natural sugars, so the intake of fructose is only half of that of sucrose under the same sweetness standard.

L-arabinose is an aldopentose, which has a blocking effect on the metabolic conversion of sucrose in the intestinal tracts of humans and animals. As a low calorie sugar, L-arabinose can selectively affect sucrase that digests sucrose in the small intestine, thereby inhibiting sucrose absorption. So that it can be extensively used in the fields of reducing weight and controlling diabetes, etc. L-arabinose has the function of regulating intestinal flora; loosening bowel to relieve constipation; improving immunity and resisting tumor; lowering blood pressure, serum cholesterol and blood glucose; preventing dental caries and removing halitosis; promoting calcium absorption. The L-arabinose can promote the proliferation of bifidobacteria in intestinal tracts, and the bifidobacteria decompose oligosaccharide to generate organic acid (fatty acid and the like) and antibiotics to inhibit the growth and the reproduction of harmful bacteria, and has beneficial effects on promoting gastrointestinal motility and balancing intestinal flora. Among a plurality of prebiotics, the L-arabinose becomes the first choice for proliferating the bifidobacterium due to the characteristics of high stability, high acid resistance, alkali resistance and the like.

Lactic acid bacteria (Lactcacid bacteria LAB) are a general term for a group of gram-positive bacteria that are not completely identical in morphology, metabolic performance and physiological characteristics. In the food industry, lactic acid bacteria are widely used, and produce important secondary metabolites during the growth and metabolism process, namely ExopolySaccharides (EPS), which are a class of carbohydrate compounds secreted by lactic acid bacteria to cell walls during the growth and metabolism process and normally oozed in culture medium, and are all products of microbial adaptation. The exopolysaccharide can be used as a stabilizer of fruit juice in fermented tomato juice.

Preferably, in step eight, the pulped tomato juice is input into a horizontal decanter centrifuge, and the feeding speed of the tomato juice and the rotating speed of the centrifuge are adjusted according to the ripeness degree, the preheating temperature and the preheating time of the tomatoes, for example, the ripeness degree of the tomatoes is ripe fruits, the fruits are full, the preheating temperature is 35-40 ℃, the preheating time is 10min, and the feeding speed of the tomato juice is 2.3-4.6L/s; the centrifugal rotating speed is 1400-2000r/min, so that a proper amount of cellulose and pectin are reserved in the tomato juice, and the stability of the tomato juice is ensured;

example 1

Firstly, selecting fresh high-quality tomatoes, grading, sorting, cleaning the tomatoes, conveying the tomatoes to a crusher and crushing; preheating the crushed tomato raw material, introducing air, heating to 35 ℃, keeping for 10min, rapidly heating to 65 ℃, and inactivating enzyme for 90 s; pulping by using a pulping machine with a screen mesh aperture of 0.6mm, removing peel and seeds, and performing horizontal screw centrifugation; 5 percent of bergamot fruit sugar (75Brix) and 10 percent of apple fruit sugar (75Brix) are added in the mixture; cooling to 40 ℃ after pasteurization, inoculating 4% of a compound strain (Lactobacillus plantarum and Streptococcus thermophilus), fermenting at 37 ℃ for about 15 hours, measuring the pH of the fermented juice to reach 3.9, adding 0.3% of L-arabinose and 0.2% of VC after the fermentation is finished, and homogenizing the fermented tomato juice at 30 mpa; degassing under the condition of 0.06Mpa of vacuum degree; sterilizing at 115 deg.C for 15s, and aseptic canning; the temperature of the sterilized and filled product is below 40 ℃. The product can be stored for 18 months.

Example 2

Firstly, selecting fresh high-quality tomatoes, grading, sorting, cleaning the tomatoes, conveying the tomatoes to a crusher and crushing; preheating and inactivating enzyme of the crushed tomato raw material at 50 ℃ for 90 s; pulping by using a pulping machine with a screen mesh aperture of 1.0mm, removing peel and seeds, and performing horizontal screw centrifugation; 8 percent of bergamot fruit sugar (75Brix) and 7 percent of apple fruit sugar (75Brix) are added in the mixture; cooling to 40 ℃ after pasteurization, inoculating 4% of compound strain (lactobacillus plantarum and streptococcus thermophilus), fermenting at 37 ℃ for about 15 hours, measuring the pH of the fermented juice to be 4.0, adding 0.3% of L-arabinose and 0.2% of tea polyphenol after the fermentation is finished, and homogenizing the fermented tomato juice for 30 mpa; degassing under the condition of vacuum degree of 0.08 Mpa; cooling to 20 deg.C, and canning. The final product is preserved at 2-5 deg.C for 21 days.

In order to further illustrate the significant progress of the technical scheme in effect, the following measures and descriptions of the nutrient components of the fermented tomato juice prepared by the technical scheme are compared with commercially available tomato juice:

1. determination of Total sugars (SB/T10203-94 general test method for fruit juices)

1.1 principle

And (3) directly titrating the calibrated alkaline copper tartrate solution by using the original reducing sugar in the sample and the reducing sugar converted after hydrolysis under the heating condition, and calculating the total sugar according to the consumed sample solution.

1.2 instruments and devices

An adjustable electric furnace: shenyang energy-saving electric furnace factory, burette, electronic balance: sidoris scientific instruments, Inc.

1.3 reagents

Weighing 15g of copper sulfate and 0.05g of methylene blue, dissolving in water, and diluting to 1000 mL;

and (3) weighing 50g of potassium sodium tartrate and 75g of sodium hydroxide, dissolving in water, adding 4g of potassium ferrocyanide, completely dissolving, adding water to a constant volume of 1000mL, and storing in a rubber-plugged glass bottle.

1mg/mL glucose standard solution, concentrated hydrochloric acid, 30% sodium hydroxide solution and 1% methyl red indicator

1.4 sample treatment

Weighing a proper amount of uniform sample (the volume of the liquid of the titrated consumed sample is required to be about 10mL according to the sugar content), adding 100mL of water (if the sample is mixed with pulp and pomace, the sample can be hydrolyzed and converted after being filtered), adding 5mL of hydrochloric acid, shaking up, placing the volumetric flask in constant-temperature water with the temperature of 68-70 ℃ for conversion for 10min, taking out and cooling to the room temperature, adding 2 drops of 1% methyl red indicator, neutralizing with 30% sodium hydroxide to be neutral, diluting with water to scale, shaking up, and placing into a burette for later use.

B, liquid A and B calibration: sucking 5mL of the solution A and the solution B respectively, putting the solution A and the solution B into a 150mL triangular flask, adding 10mL of water, dropwise adding 9.5mL of glucose standard solution from a burette, putting the burette on an electric furnace, heating the burette within 2min to boil, dropwise adding the glucose standard solution at the speed of 1 drop/2 s when the burette is boiled, and titrating until blue color fades out.

Pre-titration: sucking 5mL of the first liquid and the second liquid respectively, putting the first liquid and the second liquid into a 150mL triangular flask, adding 10mL of water, heating the flask on an electric furnace to boil, and dripping the converted sugar liquid from a burette until the blue color fades out to the end. The number of ml of test solution consumed for the titration is recorded. And (3) formal titration: sucking 5mL of the first liquid and the second liquid respectively, putting the first liquid and the second liquid into a 150mL triangular flask, adding 10mL of water, dripping the converted sugar liquid by 1mL less than that of the pre-titration, heating to boil, dripping the sugar liquid at the speed of 1 drop/2 s to the end point, and recording the milliliter number of the test solution consumed by the titration. Calculating the total sugar content (in terms of glucose) in the sample

1.5 results and analysis

Guannong fermenting tomato juice: 14.1g/100g

Commercial tomato juice: 5.7g/100g (total carbohydrate of label 5.9g/100g)

Comparing the total sugar content in the two samples shows that the total sugar content in the two products is greatly different. The sensory evaluation result also shows that the Guannong fermented tomato juice has higher sweetness than the commercial tomato juice, the former shows mellow sweet taste, and the latter shows refreshing and good taste.

2. Measurement of pectin (NY/T2016-

2.1 principle

The pectin in a sample is precipitated by absolute ethyl alcohol, the pectin is hydrolyzed to generate galacturonic acid, the galacturonic acid and a carbazole reagent are subjected to condensation reaction in sulfuric acid to generate a mauve compound, the compound has maximum absorption at 525nm, the absorption value is in direct proportion to the pectin content, and the galacturonic acid is taken as a standard substance and quantified by a standard curve method.

2.2 instruments and devices

Ultraviolet visible spectrophotometer UVIKON XL-172: SECOMAM, electronic balance: sydows scientific instruments ltd, water bath constant temperature oscillator THZ-82A: jin Tan City Ke-analysis instruments Ltd.

2.3 reagents

Absolute ethyl alcohol, concentrated sulfuric acid (super grade pure), carbazole, 40g/L sodium hydroxide solution and galacturonic acid

2.4 sample treatment

5.0g of the sample was weighed into a 50mL graduated centrifuge tube, 35mL of anhydrous ethanol at about 75 ℃ was added, and the mixture was heated in a water bath at 85 ℃ for 10min and sufficiently shaken. Cooling, adding anhydrous ethanol to make total volume close to 50mL, centrifuging at 4000r/min for 15min, and discarding supernatant. The step is repeatedly operated until no sugar in the supernatant is generated, and the supernatant is proved to contain no sugar, and the precipitate is reserved. And simultaneously, carrying out a reagent blank test.

Washing the precipitate with sulfuric acid solution with pH of 0.5, mixing, heating in 85 deg.C water bath for 60min while shaking, cooling, transferring into 100mL volumetric flask, diluting with sulfuric acid solution with pH of 0.5, filtering, and measuring the filtrate.

0.0mL of standard use solutions of 0.0mg/L, 20.0mg/L, 40.0mg/L, 60.0mg/L, 80.0mg/L and 100.0mg/L galacturonic acid are respectively sucked into a 25mL glass test tube, 0.25mL of carbazole ethanol solution is respectively added into the test tube, the test tube is continuously shaken, 5.0mL of concentrated sulfuric acid is rapidly added into the test tube, and the test tube is shaken uniformly. Immediately placing the test tube into a water bath oscillator at 85 ℃ for water bath for 20min, taking out, placing into cold water for rapid cooling, measuring the absorbance of the standard solution at the wavelength of 525nm by a spectrophotometer within 1.5h, and drawing a standard curve by taking the concentration of galacturonic acid as the abscissa and the absorbance as the ordinate. The measurement of the sample is the same as that of the standard curve, and a blank test is carried out at the same time, and the blank test solution is used for zero setting.

2.5 results and analysis

Guannong fermenting tomato juice: 3.12g/kg

Commercial tomato juice: 2.31g/kg

Comparing the content of galacturonic acid in the two samples shows that there is a difference in the pectin content between the two products. Pectin is usually derived from two sources, one being the starting material and the other being added exogenously, as a beverage thickener or stabilizer. There are two possible explanations for the above content differences if exogenous addition is not considered: 1. the raw materials used are different from tomatoes, and the content of pectin is different; 2. in the processing technology of the two products, the raw material ratio is different, the ratio of the guannong fermented tomato juice to the material water is larger, and the ratio of the commercially available tomato juice to the material water is smaller.

3. Determination of dietary fiber (GB 5009.88-2014 determination of dietary fiber in national standard food for food safety)

3.1 principle

And (3) digesting the sample by using heat-stable α -amylase, protease and glucoside to remove protein and starch, precipitating by using ethanol, filtering, washing residues by using ethanol and acetone, drying and weighing to obtain the total dietary fiber residues.

3.2 instruments and devices

Full-automatic Kjeldahl determination instrument K-360: switzerland Walker, electronic balance: sydows scientific instruments ltd, water bath constant temperature oscillator THZ-82A: jin tan city kosher instrument ltd, box resistance furnace: immersion furnace plant, vacuum filtration apparatus.

3.3 reagents

95% ethanol, heat-stable α -amylase, protease solution, glucosidase solution, sulfuric acid, hydrochloric acid, sodium hydroxide, diatomaceous earth, tris (hydroxymethyl) aminomethane, 2- (N-morphino) ethanesulfonic acid, and glacial acetic acid

3.4 sample treatment

Weighing a proper amount of sample, placing the sample in a funnel for filtering, washing the sample by using 85% ethanol solution, continuously carrying out 3 times, transferring the residue to a high-leg beaker, adding 40mL of 0.05mol/L MES-TRIS buffer solution, carrying out blank test, adding 50 mu L of heat-stable α -amylase into the sample, placing the sample in a thermostatic water bath at 95-100 ℃, continuously oscillating the sample, reacting for 35min, taking out the beaker, cooling the beaker to 60 ℃, placing the sample in 60 ℃, adding 100 mu L of protease liquid into each beaker, continuously oscillating the sample, reacting for 30min, adding 5mL of 3mol/L acetic acid solution, controlling the temperature of the sample to be 60 +/-1 ℃, adjusting the pH to 4.5 +/-0.2 by using 1mol/L of sodium hydroxide solution, adding 100 mu L of glucosidase liquid while stirring, continuously oscillating the sample in a water bath at 60 +/-1 ℃, reacting for 30min, adding 95% ethanol into the sample for precipitating for 1h, filtering the filtrate or filtering, leaving the filtrate, drying the filtrate at 105 ℃, simultaneously weighing 2 parts of the residue, subtracting the weight of the protein residue from the residue, and carrying out suction filtration to obtain the total ash content measurement.

3.5 results and analysis

Guannong fermenting tomato juice: 0.328g/100g

Commercial tomato juice: 0.287g/100g

Comparing the dietary fiber content of the two samples shows that the dietary fiber content of the two products is different. Dietary fiber is generally derived from raw materials and is generally not added from an external source. Enterprises who add dietary fiber from external sources can clearly identify the content of the dietary fiber in product labels. It can be concluded from this that the dietary fibre in both products is derived from the raw material. Similar to pectin, it is generally presumed that the ratio of the two products is different depending on the content of dietary fibers in the products. Of these, guannong fermented tomato juice is higher in water ratio, while commercially available tomato juice is lower in water ratio.

4. Determination of fatty acid (determination of fatty acid in GB 5009.168-2016 national food safety Standard)

4.1 principle

Hydrolysis-extraction method, extracting fat from sample with hydrolysis-ether solution, saponifying and methyl esterifying under alkaline condition to obtain fatty acid methyl ester, analyzing by capillary column gas chromatography, and quantitatively measuring fatty acid content by external standard method.

4.2 instruments and devices

Gas chromatograph 1260 (with hydrogen flame ion detector): agilent, electronic balance: sidoris scientific instruments, Inc.

4.3 reagents

Mixed fatty acid methyl ester standard: sigama, hydrochloric acid, diethyl ether, petroleum ether, potassium hydroxide in methanol (2 mol/L).

4.4 sample treatment

An acid hydrolysis method: food (excluding dairy and cheese): adding 10mL of hydrochloric acid solution and mixing uniformly. Putting the flask into a water bath at 70-80 ℃ for hydrolysis for 40 min. The flask was shaken every 10min to mix the particles adhering to the flask walls into the solution. After hydrolysis was complete, the flask was taken out and cooled to room temperature.

The hydrolyzed sample was mixed with 10mL of 95% ethanol and mixed well. The hydrolysate in the flask was transferred to a separatory funnel, the flask and stopper were rinsed with 50mL of ether-petroleum ether mixture, the rinse was incorporated into the separatory funnel, and the funnel was capped. Shaking for 5min, and standing for 10 min. The ether layer extract was collected in a 250mL flask. The extraction of the hydrolysate was repeated 3 times according to the above procedure, and finally the separatory funnel was rinsed with ether petroleum ether mixture and collected into a 250mL flask. Concentrating to dryness by rotary evaporator to obtain fat extract as residue.

8mL of 2% sodium hydroxide methanol solution is added into the fat extract, and the fat extract is connected with a reflux condenser and refluxed on a water bath at the temperature of 80 +/-1 ℃ until oil drops disappear. The heating was stopped, the flask was removed from the water bath and rapidly cooled to room temperature.

Accurately adding 10-30 mL of n-heptane, shaking for 2min, adding saturated sodium chloride aqueous solution, and standing for layering. Sucking the upper layer of n-heptane extraction solution about 5mL into a 25mL test tube, adding about 3g-5g anhydrous sodium sulfate, shaking for 1min, standing for 5min, sucking the upper layer of solution into a sample bottle to be measured.

4.5 detection conditions

A chromatographic column: agilent J&W HP-FFAP 30m x 250 μm x 0.25.25 μm; sample inlet temperature: 230 ℃; detector temperature: 250 ℃; temperature rising procedure: keeping at 180 deg.C for 5min, heating to 210 deg.C at 2 deg.C/min, and keeping at 5 deg.C/min to 240 deg.C for 5 min; carrier gas N₂Flow rate: 1.0 mL/min; the split ratio is as follows: 50: 1; sample introduction amount: 1 μ L.

4.6 results and analysis

Guannong fermenting tomato juice: 0.0g/100 g; commercial tomato juice: 0.0g/100g (fat content of label: 0g/100g)

As shown in FIG. 2, the fat content was 0.0g/100g in both products. The fat of tomato material mainly exists in the grains, and the fat is rich in unsaturated fatty acid and has certain nutritive value. In the tomato juice processing process, most of grains can be removed by the technological operations of removing peels and residues and the like. Therefore, the fat content in tomato juice is below the detection limit of the apparatus and method. On the other hand, the presence of unsaturated fatty acids also increases the risk of oxidative deterioration of the product during storage. The above test results show that the influence of fat does not need to be considered in the preservation process of tomato juice.

5. Determination of protein (GB 5009.5-2016 determination of protein in food of national food safety Standard)

5.1 principle

The protein in the food is decomposed under the condition of catalytic heating, and the generated ammonia is combined with sulfuric acid to generate ammonium sulfate. Alkalifying and distilling to free ammonia, absorbing with boric acid, titrating with sulfuric acid or hydrochloric acid standard titration solution, calculating nitrogen content according to acid consumption, and multiplying by conversion coefficient to obtain protein content.

5.2 instruments and devices

Full-automatic Kjeldahl determination instrument K-360: switzerland Walker, electronic balance: sidoris scientific instruments, Inc.

5.3 reagents

Copper sulfate, potassium sulfate, sulfuric acid, boric acid, sodium hydroxide and methyl red indicator

5.4 sample treatment

Sample treatment: weighing 0.2g-2g of fully-mixed solid sample, 2g-5g of semi-solid sample or 10g-25g of liquid sample (about 30mg-40mg of nitrogen), accurately measuring to 0.001g, transferring into a dry protein digestion tube, adding 0.2g of copper sulfate, 3g of potassium sulfate and 20mL of sulfuric acid, gently shaking, placing on a digestion furnace, carefully heating, completely carbonizing the content, stopping foaming, enhancing the firepower, keeping the liquid in the bottle slightly boiling, continuing to heat for 0.5h-1h after the liquid is blue-green and clear and transparent, taking down, cooling, connecting into a full-automatic Kjeldahl apparatus for distillation determination, and simultaneously performing a reagent blank test.

5.5 results and analysis

Guannong fermenting tomato juice: 1.0g/100g (protein content). Commercial tomato juice: 0.9 g/100g (nutrition label content 1.1g/100g)

The protein content of the two products did not differ much. Wherein the measured value of the protein content in the commercial tomato juice is lower than the mark content of the nutritional label. The protein and its hydrolysate small peptide and amino acid have important contribution to tomato juice flavor. The subject is based on the total protein amount measurement, and the difference of amino acid content in two products is further detected.

6. Determination of essential amino acids (GB 5009.124-2016 determination of amino acids in national food safety standards)

6.1 principle

Hydrolyzing protein in food into free amino acid with hydrochloric acid, separating with ion exchange column, reacting with ninhydrin solution, and measuring amino acid content with visible light spectrophotometry detector.

6.2 instruments and devices

Amino acid analyzer L-8900: hitachi, electric heating constant temperature air blast drying cabinet, nitrogen blowing instrument, electronic balance: sidoris scientific instruments, Inc.

6.3 reagents

Hydrochloric acid, sodium hydroxide, ninhydrin, lithium acetate, absolute ethanol, ethylene glycol monomethyl ether, sodium chloride, sodium citrate, glacial acetic acid, nitrogen, and a mixed amino acid standard solution (Hitachi Co.).

6.4 sample treatment

Accurately weighing a certain amount of sample (accurate to 0.0001g) to make the protein content in the sample within the range of 10mg-20 mg. The weighed sample is placed in a hydrolysis tube, and 10mL-15mL of 6mol/L hydrochloric acid solution is added into the hydrolysis tube. For samples with high water content and low protein content, such as beverages, fruits, vegetables and the like, hydrochloric acid with about the same volume is added and mixed, and then 6mol/L hydrochloric acid solution is added to supplement the mixture to about 10 mL. And (3) filling nitrogen into the hydrolysis tube, repeatedly filling the nitrogen for 3 times, and sealing or screwing the screw cap in the nitrogen filling state. And (3) placing the sealed hydrolysis tube in an electrothermal blowing constant temperature box or a hydrolysis furnace at 110 +/-1 ℃, hydrolyzing for 22h, taking out and cooling to room temperature. The hydrolysis tube is opened, the volume is adjusted to 50mL by water, and the mixture is shaken and mixed evenly.

Accurately sucking 1.0mL of filtrate, transferring into a test tube, drying with a nitrogen blower at 40-50 deg.C, and evaporating to dryness. Adding 1.0ml of buffer solution (instrument buffer 1) with pH2.2 into the dried test tube, dissolving, shaking, mixing, filtering with 0.22 μm filter membrane, transferring to an instrument sample bottle to obtain sample solution for instrument measurement.

6.5 detection conditions

A chromatographic column: cation column (hiti, sodium salt system), column temperature: 57 ℃ and reactor temperature: 135 ℃ and buffer flow rate: 0.40Ml/min, detection wavelength: 570nm and 440nm (proline).

6.6 results and analysis:

as shown in tables 1 and 2 and FIGS. 3-6

There was some difference in amino acid content between the two products, and the data in tables 1 and 2 were transformed to FIG. 6 in order to visually compare the difference. As can be seen from FIG. 6, the Guannong fermented tomato juice was higher than the commercial tomato juice in both total amount and each amino acid content. The amino acid can make an important contribution to the delicious taste of the tomato juice and is an important dimension for evaluating the flavor of the tomato juice. Combining the sensory evaluation condition, the sensory evaluation of the Guannong fermented tomato juice is higher than that of the Guannong fermented tomato juice sold in the market, and the Guannong fermented tomato juice shows a relatively rich tomato flavor.

Threonine	Valine	Methionine	Isoleucine	Leucine	Phenylalanine	Lysine	Total amount of
								82	51	11	36	72	92	82	426

TABLE 1

Threonine	Valine	Methionine	Isoleucine	Leucine	Phenylalanine	Lysine	Total amount of
								62	33	10	25	67	65	61	323

TABLE 2

7. Determination of vitamin C (determination of ascorbic acid in GB 5009.86-2016 national food safety Standard)

7.1 principle

And (3) carrying out redox titration on the sample acid leachate by using a blue basic dye 2, 6-dichloroindophenol standard solution, reducing the 2, 6-dichloroindophenol to be colorless, and when the titration end point is reached, enabling the redundant 2, 6-dichloroindophenol to show light red in an acid medium, and calculating the content of the L (+) -ascorbic acid in the sample according to the consumption of the 2, 6-dichloroindophenol.

7.2 instruments and devices

An electronic balance: sartorius scientific instruments ltd, organization triturator.

7.3 reagents

Oxalic acid, vitamin C standard substance, 2, 6-dichloroindophenol and kaolin

7.4 sample treatment

100g of solid edible part with representative sample is weighed and put into a crusher, 100g of oxalic acid solution is added, and the mixture is quickly smashed into homogenate (liquid sample can be directly weighed). Accurately weighing 10g-40g homogenate sample (accurate to 0.01g) in a beaker, transferring the sample to a 100mL volumetric flask with oxalic acid solution, diluting to scale, shaking up and filtering. If the filtrate is colored, 0.4g of kaolin is added into each gram of sample for decolorization and then filtration is carried out.

Calibrating the dye: accurately sucking 1mL of ascorbic acid standard solution into a 50mL conical flask, adding 9mL of oxalic acid solution, shaking up, titrating to pink with 2, 6-dichloroindophenol solution, and keeping the solution for 15 s. Meanwhile, another 10mL of oxalic acid solution is taken for a blank test.

And (3) sample titration: accurately pipette 10mL of the filtrate into a 50mL Erlenmeyer flask and titrate with a calibrated solution of 2, 6-dichloroindophenol until the solution is pink for 15 seconds without fading. And simultaneously performing a blank test.

7.5 results and analysis

Guannong fermenting tomato juice: 2.16mg/100 g; commercial tomato juice: 3.49mg/100g

The vitamin C content of the two products is different, and the vitamin content of the commercial tomato juice is about 1.61 times of that of Guannong fermented tomato juice. Vitamin C is an inherent component in tomato juice and can also be added from other sources to be used as a nutritional supplement or an antioxidant. Meanwhile, the slightly acidic taste of the vitamin C solution also has certain influence on the sensory quality of the tomato juice. In combination with the above ingredient analysis, the feed-to-liquid ratio of the commercial tomato juice is lower than that of the Guannong fermented tomato juice, but the content of vitamin C is significantly higher than that of the Guannong fermented tomato juice, which suggests that the commercial tomato juice may be added with vitamin C from an external source.

8. Determination of vitamin B1 (determination of vitamin B1 in GB 5009.84-2016 national food safety Standard)

8.1 principle

Hydrolyzing and neutralizing the sample in a dilute hydrochloric acid medium at constant temperature, performing enzymolysis, deriving the hydrolysate with an alkaline potassium ferricyanide solution, extracting with n-butanol, separating by a C18 reversed phase chromatographic column, detecting by a high performance liquid chromatography-fluorescence detector, and quantifying by an external standard method.

8.2 instruments and devices

High performance liquid chromatograph 1260 (with fluorescence detector): agilent, high pressure steam sterilizer: japan ocean corporation, electronic balance: sydows scientific instruments ltd, constant temperature oscillator THZ-82A: jintan city koesa instruments ltd, PH meter: sidoris scientific instruments, Inc.

8.3 reagents

N-butanol, potassium ferricyanide, sodium hydroxide, hydrochloric acid, glacial acetic acid, sodium acetate, methanol, papain, amylase, vitamin B1 standard (carbofuran reagent, Inc.).

8.4 sample treatment

Extracting a test solution: weighing 3g-5g (accurate to 0.01g) of solid sample or 10g-20g of liquid sample into a 100mL conical flask (with a soft stopper), adding 60mL of 0.1mol/L hydrochloric acid solution, fully shaking, plugging the soft stopper, and keeping the temperature of 121 ℃ for 30min in an autoclave. After hydrolysis, cooling to below 40 ℃, taking out, and shaking gently for several times; using a pH meter to indicate, adjusting the pH to about 4.0 by using 2.0mol/L sodium acetate solution, adding 2.0mL (the dosage can be properly adjusted according to different enzyme activities) of mixed enzyme solution of papain and amylase, shaking uniformly, and placing in an incubator at 37 ℃ overnight (about 16 h); transferring all the enzymolysis liquid into a 100mL volumetric flask, adding water to a constant volume to a scale, shaking up, centrifuging or filtering, and taking supernatant for later use.

Derivation of a test solution: accurately transferring 2.0mL of the supernatant or the filtrate into a 10mL test tube, adding 1.0mL of alkaline potassium ferricyanide solution, uniformly mixing by vortex, accurately adding 2.0mL of n-butanol, uniformly mixing by vortex again for 1.5min, standing for about 10min or centrifuging, after full layering, absorbing n-butanol phase (upper layer) and filtering by a 0.45 mu m organic microporous filter membrane, and taking the filtrate into a 2mL brown sample feeding bottle for analysis. Vitamin in the test solution

And (3) when the concentration of biotin B1 exceeds the highest concentration value of a linear range, taking the supernatant, diluting by a proper time, and carrying out derivatization and then injecting. Another 2.0mL standard series working solution was simultaneously derivatized with the test solution.

8.5 detection conditions

A chromatographic column: agilent ZorbaxStableBond Analytical C184.6mm x 150mm x 5.0 μm; detection wavelength: excitation wavelength 375nm and emission wavelength 435 nm; mobile phase: methanol +0.05mol/L sodium acetate (35+65, vol.); flow rate of mobile phase: 0.80 mL/min.

8.6 results and analysis

Guannong fermenting tomato juice: 0.0316mg/100 g; commercial tomato juice: 0.0337mg/100g,

according to the detection results, the content of the vitamin B1 in the two products is not greatly different. Since the limit of quantitation of this method is 0.05mg/100g, the above results are only qualitative detections, as shown in FIGS. 7-9.

9. Determination of vitamin B2 (determination of vitamin B2 in GB 5009.85-2016 national food safety Standard)

9.1 principle

Hydrolyzing the sample at constant temperature in a dilute hydrochloric acid environment, adjusting pH to 6.0-6.5, performing enzymolysis with papain and high-peak amylase, performing constant volume filtration, separating the filtrate by a reversed phase chromatographic column, detecting by a high performance liquid chromatography fluorescence detector, and quantifying by an external standard method.

9.2 instruments and devices

9.3 reagents

N-butanol, potassium ferricyanide, sodium hydroxide, hydrochloric acid, glacial acetic acid, sodium acetate, methanol, papain, peaked amylase, vitamin B2 standard (carbofuran reagent limited).

9.4 sample treatment

Extracting a test solution: weighing 3g-5g (accurate to 0.01g) of solid sample or 10g-20g of liquid sample into a 100mL conical flask (with a soft stopper), adding 60mL of 0.1mol/L hydrochloric acid solution, fully shaking, plugging the soft stopper, and keeping the temperature of 121 ℃ for 30min in an autoclave. After hydrolysis, cooling to below 40 ℃, taking out, and shaking gently for several times; using a pH meter to indicate, using 1mol/L sodium hydroxide solution to adjust the pH to about 6.0-6.5, adding 2.0mL (the dosage can be properly adjusted according to different enzyme activities) of mixed enzyme solution of papain and amylase, shaking uniformly, and placing in an incubator at 37 ℃ overnight (about 16 hours); transferring all the enzymatic hydrolysate into a 100mL volumetric flask, adding water to a constant volume to a scale, shaking up, centrifuging or filtering, and passing the supernatant through a 0.45-micron water-phase filter membrane to serve as a solution to be detected.

9.5 detection conditions

A chromatographic column: agilent ZorbaxStableBond Analytical C184.6mm x 150mm x 5.0 μm; detection wavelength: the excitation wavelength is 462nm, and the emission wavelength is 522 nm; mobile phase: methanol +0.05mol/L sodium acetate (35+65, vol.); flow rate of mobile phase: 1.0 mL/min.

9.6 results and analysis

Guannong fermenting tomato juice: 0.0344mg/100 g; commercial tomato juice: 0.0205mg/100 g;

according to the detection results, the content of the vitamin B2 in the two products has a certain difference. The content of vitamin B2 in Guannong fermented tomato juice is 1.68 times of that in the commercial tomato juice. Vitamin B2 has two sources, one from the raw material tomato itself and the other from microbial fermentation metabolites. The higher vitamin B2 content in Guannong fermented tomato juice is related to the higher feed-liquid ratio on one hand and the special fermentation process on the other hand. Micromolecular metabolites are generated in the fermentation process, the nutritive value of the product is improved, the fermentation product can be further induced and carded in subsequent research, the change rule of the micromolecular metabolites before and after fermentation is monitored, and the product characteristics of Guannong fermented tomato juice are objectively summarized. As shown in fig. 10-12.

10. Determination of carotene (GB 5009.83-2016 determination of carotene in national food safety standard)

10.1 principle

Saponifying the sample to release carotene into free state, extracting dichloromethane with petroleum ether to constant volume, separating by reverse phase chromatography, and quantifying by external standard method.

10.2 instruments and devices

High performance liquid chromatograph 1100 (with uv detector): agilent, electronic balance: sydows scientific instruments ltd, water bath constant temperature oscillator THZ-82A: jintan city discriminant instruments ltd, rotary evaporator: shanghai Yangrong Biochemical Instrument plant.

10.3 reagent

Potassium hydroxide, ethanol, petroleum ether, methylene chloride, anhydrous sodium sulfate, β -carotene standard (carbofuran reagent).

10.4 sample treatment

Accurately weighing 1g-5g (accurate to 0.001g) of a uniformly mixed sample of common food such as vegetables, fruits, bacteria and algae, grains, beans, eggs and the like, accurately weighing 0.2g-2g (accurate to 0.001g) of oil, transferring the sample into a 250mL conical flask, adding 1g of ascorbic acid, 40mL of absolute ethyl alcohol and 10mL of potassium hydroxide solution, carrying out water bath oscillation and saponification at 60 +/-1 ℃ for 30min, taking out, standing and cooling to room temperature.

Transferring the saponified solution into 500mL separating funnel, adding 100mL petroleum ether, shaking gently, exhausting, covering bottle stopper, shaking at room temperature for 10min, standing for layering, transferring the water phase into another separating funnel, and performing second extraction according to the above method. The organic phases were combined and washed with water to near neutrality. The aqueous phase was discarded and the organic phase was filtered and dehydrated over anhydrous sodium sulfate. The filtrate was taken in a 500mL evaporation flask, concentrated on a rotary evaporator at 40 ℃. + -. 2 ℃ under reduced pressure, and dried. Blowing the mixture to dryness by using nitrogen, accurately adding 5.0mL of dichloromethane into the mixture by using a pipette, covering a bottle stopper, and fully dissolving and extracting

And (6) taking the object. After filtration through a 0.45 μm membrane, the initial about 1mL of filtrate was discarded and collected into a sample bottle for further use.

10.5 detection conditions

A chromatographic column: agilent ZORBAX Eclipse Plus C184.6mm x 150mm x 5.0 μm; detection wavelength: 450 nm; mobile phase: methanol + acetonitrile (90+10 by volume); flow rate of mobile phase: 1.0 mL/min.

10.6 results and analysis

Guannong fermenting tomato juice: 64.4. mu.g/100 g, commercial tomato juice: 21.3 mu g/100 g;

as shown in FIGS. 13-15, the difference between the carotene contents of the two products was observed. The carotene content in Guannong fermented tomato juice is nearly 3 times that of the commercial tomato juice. There are two sources of carotene, one from the raw material tomato itself and the other from microbial fermentation metabolites. The higher carotene content in Guannong fermented tomato juice is related to the higher feed-liquid ratio on one hand and the special fermentation process on the other hand. In the present subject, it is worth further investigation in the subsequent studies whether the strain used in the fermentation will synthesize carotene under the experimental conditions.

11. Determination of lycopene (high performance liquid chromatography for determination of lycopene in NY/T1651-2008 vegetables and products)

11.1 principle

Extracting lycopene in vegetables and products with acetone-petroleum ether mixed solution, extracting with petroleum ether, adding dichloromethane to desired volume, measuring with high performance liquid chromatograph equipped with ultraviolet detector at wavelength of 472nm, and quantifying according to retention time of chromatographic peak and external standard method.

11.2 instruments and devices

High performance liquid chromatograph 1100 (with uv detector): agilent, electronic balance: sartorius scientific instruments ltd, rotary evaporator: shanghai Yangrong Biochemical Instrument plant.

11.3 reagents

Acetone, petroleum ether, dichloromethane, methanol, acetonitrile, lycopene (Sigama corporation)

11.4 sample treatment

Fully and uniformly mixing the samples, weighing 5g of vegetable or juice samples, weighing 2g of sauce products, accurately weighing to 0.01g, placing the mixture into a 150mL beaker, adding a proper amount of acetone-petroleum ether mixed solution until the samples are completely submerged, stirring by using a glass rod, standing to fully dissolve the lycopene, then transferring the mixture into a sand-cored funnel for vacuum filtration, collecting filtrate in a test tube, and repeating the steps until the samples are washed to be colorless.

Transferring the extract in the test tube to a separating funnel, standing for layering, collecting the upper organic phase in a round bottom flask through a glass funnel filled with anhydrous sodium sulfate, extracting the lower aqueous phase with 20mL of petroleum ether, collecting the organic phase, filtering the organic phase in the round bottom flask, concentrating at 40 +/-2 ℃ on a rotary evaporator under reduced pressure, and drying. Blow-dry with nitrogen, add exactly 5.0mL of dichloromethane with a pipette, cap the stopper, and dissolve the extract thoroughly. After filtration through a 0.45 μm membrane, the initial about 1mL of filtrate was discarded and collected into a sample bottle for further use.

11.5 detection conditions

A chromatographic column: agilent ZORBAX Eclipse Plus C184.6mm x 150mm x 5.0 μm; detection wavelength: 472 nm; mobile phase: methanol + acetonitrile + dichloromethane (20+75+5, volume ratio); flow rate of mobile phase: 1.0 mL/min.

11.6 results and analysis

Guannong fermenting tomato juice: 69.4mg/kg, commercial tomato juice: 53.1 mg/kg;

as shown in fig. 16-18, the results of the tests showed that there was a difference in the lycopene content between the two tomato juices, and the lycopene content in the guanong fermented tomato juice was higher than that in the commercial tomato juice. From the perspective of sensory effect, although the difference of lycopene content between the two is different in detection value, the difference of sensory effect is not large, namely: the tasters did not clearly differ in the "degree of redness" of the two tomato juices.

12. Determination of elements (Ca, Zn, Fe, K) (GB 5009.268-2016 determination of multiple elements in national food safety standard)

12.1 principle

After the sample is digested, measuring by an inductively coupled plasma emission spectrometer, and determining by the characteristic spectral line wavelength of an element; and (4) quantitatively analyzing the to-be-detected element spectral line signal intensity in direct proportion to the element concentration.

12.2 instruments and devices

Inductively coupled plasma emission spectrometer (seemer femoris technologies ltd), electrothermal digestion board (lebettec ltd), electronic balance: sidoris scientific instruments, Inc.

12.3 reagents

Perchloric acid, concentrated nitric acid, multi-element mixed solution (national standard substance center) and argon (more than or equal to 99.995 percent)

12.4 sample treatment

Accurately weighing 0.5-5 g (accurate to 0.001g) or accurately transferring 2.00-10.0 mL of sample into a glass triangular flask, heating the sample containing ethanol or carbon dioxide on an electric heating plate at low temperature to remove the ethanol or carbon dioxide, adding 6mL of nitric acid-perchloric acid (4+1) mixed solution, digesting on the electric heating plate, adding a small amount of mixed acid if the digestion solution turns brown and black in the digestion process until white smoke appears, cooling, adding water to a constant volume of 25mL, and mixing uniformly for later use. And simultaneously performing a blank test.

12.5 detection conditions

RF power: 1150w, cooling gas: 10L/min, atomizer flow: 0.5L/min, auxiliary gas flow: 0.5L/min, pump speed: 50 rpm.

12.6 results and analysis

From the detection data in table 3, it can be seen that, of the four trace elements detected, the Ca and K contents of guannong fermented tomato juice are higher than those of the commercial tomato juice, and the Zn and Fe contents are slightly lower than those of the commercial tomato juice. The two are not greatly different as a whole. The main source of the trace elements is raw materials, and in the processing process, the trace elements are reduced due to the loss of the raw materials but cannot be converted. Therefore, the difference of trace elements in the raw materials can directly result in the difference of trace elements in the product. The content difference of the trace elements in the raw materials is closely related to the variety of the raw materials on one hand and the planting environment and conditions on the other hand. Different varieties or different planting environments and conditions can cause the content of trace elements in the raw materials to change greatly. Therefore, from the above-mentioned detection results, the rule of the trace element content difference between two tomato juices cannot be summarized well, and it is difficult to infer the source of the trace element content difference between two tomato juices. The influence of the trace elements on the tomato juice quality is mainly reflected in the aspect of the nutritional quality, and the influence on the sensory quality and the safety quality of the tomato juice is little. As shown in fig. 19-22.

Product(s)	Ca	Zn	Fe	K
					Guannong fermented tomato juice	86.4	1.42	2.96	1.24×10³
Tomato juice commercially available	67.7	2.04	3.19	1.02×10³

TABLE 3

13. Determination of Total acid (determination of Total acid in GB/T12456-

13.1 principle

According to the acid-base neutralization principle, acid in the alkali liquid is dripped to determine the titration end point by taking phenolphthalein as an indicator. And calculating the total acid content in the food according to the consumption of the alkali liquor.

13.2 instruments and devices

An electronic balance: sidolisi scientific instruments, Inc., water baths, burettes.

13.3 reagents

Sodium hydroxide, hydrochloric acid, phenolphthalein

13.4 sample treatment

Weighing 10g to 50g of sample, placing the sample in a 100mL beaker, transferring the content in the beaker into a 250mL volumetric flask by using water boiled at about 80 ℃, placing the flask in a boiling water bath for boiling for 30min (shaking for 2 to 3 times during the process to completely dissolve organic acid in the sample in the solution), taking out the flask, cooling the flask to room temperature, metering the volume of the water to 250mL, filtering the solution by using filter paper, and collecting the filtrate for measurement. Transferring 20mL of filtrate, adding 40-60 m of water, adding two drops of phenolphthalein indicator, and titrating with 0.1mol/L sodium hydroxide standard titration solution until reddish color does not fade for 30 s. And simultaneously, carrying out a reagent blank test.

13.5 results and analysis

Guannong fermenting tomato juice: 9.12g/kg, commercial tomato juice: 7.82 g/kg;

the content of the total acid is closely related to the sensory quality of the product, and the evaluation of the taster on the acidity of the product is directly influenced. The content of total acid in the two products is different, the content of total acid in the Guannong fermented tomato juice is slightly higher than that of the commercially available tomato juice, the detection result is consistent with the sensory evaluation result, and the sensory acidity of the Guannong fermented tomato juice is slightly higher than that of the commercially available tomato juice. The content of each organic acid in the total acid is reported herein.

14. Determination of organic acid (GB 5009.157-2016 determination of organic acid in national food safety Standard)

14.1 principle

Directly diluting the sample with water or extracting with water, purifying with strong anion exchange solid phase extraction column if necessary, separating with reversed phase chromatographic column, and quantifying with retention time and external standard method.

14.2 instruments and devices

High performance liquid chromatograph 1100 (with uv detector): agilent, electronic balance: sidoris scientific instruments, Inc.

14.3 reagents

Methanol, absolute ethanol, phosphoric acid, organic acid (tartaric acid, malic acid, citric acid, succinic acid) standard: sigama corporation.

14.4 sample treatment

Weighing 5g of uniform sample, putting the sample into a 25mL volumetric flask, adding water to the scale, filtering the sample by a 0.45 mu m membrane, and injecting the filtered sample into a high performance liquid chromatograph for analysis. If the matrix is complex, the sample filtrate can be purified by a strong anion exchange solid phase extraction column, and the purified liquid is used for high performance liquid chromatography analysis.

14.5 detection conditions

A chromatographic column: agilent ZORBAX Eclipse Plus C184.6mm x 150mm x 5.0 μm; detection wavelength: 210 nm; mobile phase: methanol + 0.1% phosphoric acid solution (25+75 by volume); flow rate of mobile phase: 1.0 mL/min.

14.6 results and analysis

As shown in table 4, where the tartaric acid quantitative limit: 0.25 g/kg.

The experiment selects common organic acids in three plant raw materials of citric acid, malic acid and tartaric acid. Tartaric acid was not detected in both samples, and citric acid and malic acid were detected in both samples. In the Guannong fermented tomato juice, the contents of the two types of detected organic acids are higher than those of the commercial tomato juice, the citric acid is 1.2 times higher, and the malic acid is 1.1 times higher. The detection result is consistent with the detection result of the total acid, the Guannong fermented tomato juice contains more organic acid, and the acidity is higher; whereas commercially available tomato juice has a relatively low acidity and a slightly lower organic acid content. As shown in fig. 23-25.

Product(s)	Citric acid	Malic acid	Tartaric acid
				Guannong fermented tomato juice	3.6	2.8	Not detected out
Tomato juice commercially available	3.0	2.5	Not detected out

TABLE 4

15. Determination of soluble solids (refractometer method for determination of soluble solids content in NY/T2637-2014 fruits and vegetables)

15.1 principle

The refractive index of the sample liquid is measured by a refractometer, and the soluble solid content of the sample liquid is read from a display or a graduated scale and is expressed by the mass percentage of the sucrose.

15.2 instruments and devices

Abbe refractometer

15.3 sample treatment

The solid sample is mashed to obtain juice, and the liquid sample is directly filtered to obtain the juice to be measured. The refractometer was calibrated with distilled water at 20 ℃ and the soluble solids reading was adjusted to 0, which is necessary when the ambient temperature is not at 20 ℃. Keeping the measuring temperature stable, dripping 2-3 drops of sample liquid to be measured to uniformly distribute the sample liquid on the surface of the prism, aligning a light source, adjusting a knob to enable a visual field bright-dark cut-off line to be positioned on a cross point, and recording the reading of a refractometer to obtain the content of soluble solid matters.

15.4 results and analysis

Guannong fermenting tomato juice: 13.2%, commercial tomato juice: 9.1 percent;

according to the measurement result, the soluble solid content in the Guannong fermented tomato juice is 1.5 times higher than that in the commercially available tomato juice, and the Guannong fermented tomato juice has sweetness, higher viscosity and thickness and stronger mouthfeel by combining the effect of sensory evaluation, while the commercially available tomato juice has slightly lower sweetness, viscosity and thickness and shows relatively light mouthfeel. The measurement result of the soluble solid content is consistent with the effect of sensory evaluation.

16. Colorimetric analysis

The results of the colorimetric analysis of the two products are shown in table 5 and fig. 26, wherein: the cross hair and background color set default values for the system and are not used as the basis or standard for result evaluation.

Based on CIELAB color space analysis, a comparison of the numerical differences of the two tomato juices L, a, b showed that, in lightness, the guanong fermented tomato juice was darker than the commercial tomato juice; in red-green shades, commercial tomato juice is redder than coronafamon fermented tomato juice; in the yellowness hue, commercial tomato juice is more yellow than coronafion fermented tomato juice.

TABLE 5

17. Total evaluation of product nutritional ingredients

By combining the measurement of total sugar, soluble solid and sensory evaluation indexes, compared with the similar products sold in the market, the Xinjiang Guannong fermented tomato juice has higher sweetness, viscosity and consistency and has finer and thicker mouthfeel.

The protein and hydrolysate small peptide and amino acid thereof have important contribution to the nutritional quality and flavor of tomato juice. The content of Chinese protein in the product is 1.0g/100g, which is much higher than that of common fruit juice beverage, and is close to that of most vegetable protein beverages sold in the market; the content of each essential amino acid and the total amount of the amino acid are higher than those of the similar products sold in the market, wherein the total amount of the amino acid in the products is 426mg/100g, which is about 1.3 times of that of the similar products sold in the market.

In the aspect of vitamin content, three vitamins, namely vitamin B2, vitamin C and vitamin B1, are emphatically detected in the experiment. The vitamin B2 content in the product is rich and is 1.68 times of that of the similar products sold in the market. The content of vitamin C is 2.16mg/100g, which is lower than that of the similar products sold in the market, and the vitamin C of the products sold in the market is supposed to be added externally. However, the content of the vitamin B1 is 0.0316mg/100g, which is close to that of the similar products sold in the market.

In the aspect of natural pigment content, β -carotene and lycopene are determined by the experiment, β -carotene has prominent effects on maintaining cardiovascular and cerebrovascular health, eliminating free radicals and preventing cancers, the carotene content in the product is 64.4ug/100g and is close to 3 times of the content of similar products sold in the market, the lycopene is a main element pigment of mature tomatoes and has multiple effects of resisting oxidation, reducing blood fat and cardiovascular disease risks, inhibiting tumors, improving body immunity and the like, the lycopene content in the product is 69.4mg/100g which is slightly higher than similar products sold in the market, the comprehensive chromaticity detection result and the sensory effect are achieved, and the lycopene level in the product is approximately equivalent to that of similar products sold in the market.

The tomato juice contains abundant trace elements, and has important effect on human health. According to the results, the Ca content (86.4mg/kg) and the K content (1.24X 10) of the four detected trace elements of Ca, K, Zn and Fe are shown³mg/kg) are higher than those of the similar products sold on the market, and the Zn content (1.42mg/kg) and the Fe content (2.96mg/kg) are slightly lower than those of the similar products sold on the market.

The content of the total acid is closely related to the sensory quality of the product, and the evaluation of the taster on the acidity of the product is directly influenced. The total acid content of the product is 9.12g/kg, which is slightly higher than that of the similar products sold in the market, and the detection value is consistent with the sensory evaluation result. The organic acid in the tomato juice has multiple health-care effects of protecting vitamin C, softening blood vessels, promoting absorption of calcium and iron elements and the like, so common organic acids in three plant raw materials of citric acid, malic acid and tartaric acid are selected for further analysis in the experiment. The citric acid content is 3.6g/kg, which is 1.2 times of the same kind of products sold in the market; the malic acid content is 2.8g/kg, which is 1.1 times of the similar products sold in the market; tartaric acid was not detected in any of the samples.

The experiment also quantitatively detects fatty acids. The detected result is lower than the detection limit of an instrument and a method, the fat content is 0.0g/100g, and the result is consistent with the fat content and the label identification result of a commercial product. The nutritional value of unsaturated fatty acids and the risk of oxidative deterioration during storage are taken into account, and the influence of fat can be disregarded.

The technical solutions described above only represent the preferred technical solutions of the present invention, and some possible modifications to some parts of the technical solutions by those skilled in the art all represent the principles of the present invention, and fall within the protection scope of the present invention.

Claims

1. A preparation method of nutritional compound lactobacillus fermented tomato juice is characterized by comprising the following steps:

step one, checking and accepting raw materials: selecting fresh tomatoes with proper maturity, bright red color, no insect pest and high soluble solid content as raw materials.

Step two, cleaning raw materials: the tomatoes are cleaned by adopting five-grade water, and then are primarily disinfected by adopting subacid electrolyzed water and removed of silt.

And step three, grading, namely removing the green and yellow fruits in the raw materials by adopting a water buoyancy grading method according to the density relation of the raw materials.

And step four, sorting, namely sorting the raw materials, and removing unqualified fruits such as rotten fruits, cracked black spot fruits, worm eaten fruits and the like in the raw materials.

And step five, crushing, namely crushing the sorted tomato raw materials by a crushing pump and conveying the crushed tomato raw materials to a preheating storage tank.

And step six, preheating and inactivating enzyme, namely slowly heating the raw materials in the preheating storage tank to 35-40 ℃ in an air-introducing environment, then keeping for 10min, and quickly raising the temperature to 65 ℃ for preheating and inactivating enzyme.

And seventhly, pulping, namely inputting the preheated enzyme-inactivated raw materials into a pulping machine for pulping, wherein a screen of the pulping machine is a 0.6-1.0mm screen, and removing tomato skins and seeds through pulping to obtain tomato juice.

And step eight, centrifuging, namely inputting the pulped tomato juice into a horizontal screw centrifuge, and adjusting the feeding speed of the tomato juice and the rotating speed of the centrifuge according to the maturity, the preheating temperature and the preheating time of the tomatoes to ensure that a proper amount of cellulose and pectin are reserved in the tomato juice and the stability of the tomato juice is ensured. ]

And step nine, blending, namely adding apple fructose of 75Brix into the tomato juice after the centrifugal treatment, and adding bergamot pear fructose of 75Brix into the tomato juice to fully dissolve the apple fructose and uniformly mix the apple fructose and the bergamot pear fructose into the tomato juice.

Tenth, sterilizing, namely performing pasteurization on the blended tomato juice, and then cooling to 40 DEG C

step twelve, inoculation, namely inoculating the two activated lactobacillus leavening agents into the cooled tomato juice according to the inoculation amount of 2%, and fermenting at 40 ℃ for 12-18h to obtain fermented juice;

and thirteen, fermenting, namely determining the fermentation end point of the fermented juice by combining sensory evaluation when the pH value of the fermented juice is between 3.85 and 4.05.

And step fourteen, homogenizing, namely inputting the fermented tomato juice into a homogenizer, refining pulp and fiber components through the homogenizer, and enhancing the stability.

And a fifteenth step of degassing, wherein the homogenized tomato juice is degassed by adopting a vacuumizing and degassing technology, and the degassing pressure is 0.06-0.08 MPA.

Sixthly, performing secondary sterilization, namely performing sterilization on the degassed tomato juice by using a UHT sterilization process, wherein the sterilization temperature is 115 ℃, and the sterilization time is 15 s.

Seventhly, canning, and performing aseptic canning on the juice subjected to secondary sterilization.

2. The method for preparing tomato juice fermented by lactic acid bacteria in nutritional type according to claim 1, wherein in the first step, the soluble solid content of tomato is 4.5% -6.0%.

3. The method for preparing nutritional compound lactobacillus fermented tomato juice according to claim 1, wherein in the sixth step, the temperature of the raw material in the preheating storage tank is slowly raised to 35 ℃, and then kept for 10 min.

4. The method for preparing nutritional compound lactobacillus fermented tomato juice according to claim 1, wherein in the seventh step, a screen with a hole diameter of 0.8mm is adopted as a screen of a beater.

5. The method for preparing nutritional compound lactobacillus fermented tomato juice according to claim 1, wherein after the fermentation process of the third step is completed, L-arabinose, tea polyphenol, citric acid, VC and the like are added according to production needs for secondary blending.

6. The method for preparing tomato juice fermented by lactic acid bacteria in nutritional type according to claim 1, wherein in the eighth step, the feeding speed of tomato juice is 2.3-4.6L/s; the centrifugal rotating speed is 1400-2000 r/min.

7. The method for preparing nutritional compound lactobacillus fermented tomato juice according to claim 1, wherein in the ninth step, the amount of apple fructose added is 5% -8%, the amount of bergamot fructose added is 8% -10%, and the amount of L-arabinose added is 0.3%.

8. The method for preparing nutritional compound lactobacillus fermented tomato juice according to claim 1, wherein in the eleventh step, the concentration of the skim milk is 13%.

9. The method for preparing nutritional compound lactobacillus fermented tomato juice according to claim 1, wherein in the seventeen steps, the shelf life of the aseptically filled tomato juice is 18 months.