research on vinegar production process and product development fruit vinegar made from pineapple

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURAL AND FORESTRY TRINH MANH TRUONG RESEARCH ON VINEGAR PRODUCTION PROCESS AND PRODUCT DEVELOPMENT FRUIT VINEGAR MADE FROM PINEAPPLE BACHELOR

INTRODUCTION

Question

In the northern mountainous provinces, pineapple has an important position in vegetable production because it can withstand external conditions and recovers capital early, so it is one of the strategies to improve farmers' lives Because of its potential, it is planted in many localities throughout the provinces of Bac Kan, Phu Tho, Nghe An, Lam Dong, Tien Giang,

Nowadays, the demand of consumers to use natural food products seems to become a trend and the research works on them are also constantly evolving and the effectiveness of different types of food This product is quite high compared to similar synthetic products Practical studies have shown that when using products of plant origin, there are few harmful side effects and this is an important reason that today natural products are increasingly developed strong

Vietnam has very favorable natural conditions for the development of fruits, in which there are many species of plants containing natural nutritional value that can take advantage of the flesh of the fruit In particular, pineapple tree is a potential plant, but has not been exploited and taken advantage of properly In recent years, the expansion of pineapple growing area has become rampant, with no clear market orientation, so people's consumption and purchase of pineapples has become precarious, depending entirely on traders Meanwhile, the area of raw materials for citrus crops such as pineapple forest in and outside the province has grown very strongly, consumers have more choices when buying fruit for food

The reasons make the market price of this fruit tree much lower, plus extreme weather, prolonged heavy rain at the time of harvest, which reduces yield due to rotting and damaged pineapples, which have caused pineapple gardens to fall From a place of high economic profit, it becomes a crop of low economic value and people have a need to destroy gardens and change crop structure, thus helping farmers to solve the urgency of the topic should be taken care of and implemented

The in practice, identified as a key agricultural product of some provinces, many topics and projects develop growing areas, research and apply technological processes in cultivation to increase productivity and quality for pineapple species has been implemented, there are many dried products, jams, canned pineapple juice from fruits like on the Vietnamese market We have an abundant source of domestic products, but we have not taken full advantage of it local people consume pineapple That situation it is necessary to research and find solutions to increase the value of pineapples by taking advantage of raw materials that are poorly designed pineapples, falling pineapples to avoid waste Realizing that pineapple contains a lot of nutritional components and to help farmers consume agricultural products to new consumption directions for this fruit, bringing higher economic efficiency to pineapple farmers

Stemming from the above practice, we conducted research on pineapple vinegar production process to improve the economic value and quality of the product.

Objectives of the study

Study on the influence of factors affecting the pineapple vinegar production proces

Detail goal: a) Research on optimization of factors affecting the pineapple vinegar production process

- Research to determine the amount of dry substance dissolving fermentation

- Research to determine the suitable pH for fermentation - Research optimization to determine the appropriate fermentation time for the process - Research on optimization to determine the appropriate fermentation temperature for the process a) Research on optimizing the substances in pineapple vinegar b)Complete the process

Detail goal

The research results of the topic will provide new scientific data on:

- The influence of ingredients on fermentation was determined in pineapple vinegar fermentation

- Evaluate some factors affecting the pineapple vinegar production process - Developed a production process for pineapple vinegar

Limitations

Students gain practical experience in scientific research, consolidate theoretical knowledge, apply in practice to perfect themselves in order to develop foundations, skills at work, and practice professional attitudes correct, refer to observational assessment, study, read more books and internet to understand more about the research topic accumulated experience must practice more research skills

- Follow the arrangement instructions of the trainers as well as the assistant coaches in the implementation of the topic Follow the work plan, provide timely supplementary instructions to suit the conditions of knowledge exchange activities from teachers in order to accumulate experience, carefully review the contents of preparing for the report and ask for opinions about problems that arise during the internship

- The research results of the topic will partly contribute to the study of the fruit vinegar production process that brings value, health and economy to the community.

LITERATURE REVIEW

Scientific basis of the topic

Scientific name: Pineapple Ananas comosus L (Merrill) Belongs to the family: Bromeliaceae

Genus: Ananas Foreign names: Mauritius (India), Red Malacca (Malaysia), Sugarloaf (Philippines) ,

Pineapple has the scientific name Anamas comosus L/(Merill), belongs to the family Bromeliaceae, genus Ananas Pineapple is a tropical fruit tree, pineapple species brings very high nutritional value and is considered an ideal fruit for all ages, especially all pineapple products can be used as food, fertilizer

Vietnamese pineapple stands out with 3 main classification varieties:

- Queen group (Queens): Pineapple belongs to this group of medium weight and size, convex eyes, carrying capacity, dark yellow flesh, characteristic sweet aroma

This is a group of pineapples with the highest quality that are commonly grown in our country and are called pineapple flowers or pineapples

- Cayene group (Caine) This type has a large fruit mass, sometimes up to 3 kg, ivory yellow flesh, more water, less fragrant and less sweet than pineapple flowers

This variety in many countries in the region it is grown a lot for processing because its large fruit is easy to mechanize and gives high economic efficiency Currently, Vietnam is developing this pineapple variety (Singh et al., 2004)

- Spanish group (Spain) This pineapple has a larger fruit size than flower pineapple, The flesh of the fruit is pale yellow to white, less fragrant, sour, more watery

2.1.2 Nutritional composition and uses of pineapple

Pineapple is considered a fruit with a rich flavor and a very clear scent that is not mixed with other fruits that are rich in nutrients from the fruit pulp (Wooster and Blank,1950) gave the following results after analyzing the Cayenne pineapple variety grown in Hawaii, including the following components:

Table 2.2 Nutritional facts of ingredients in pineapple

Glucose 4,7 % accarose 13,7 % a Pineapple ropes and flowers b Pineapple seeds

Figure 2.1 Pineapple ropes, flowers and seeds 2.1.3 Research works in the world and in the country Several studies on pineapples in the world

According to statistics (Anon, 2002) collected from FAO (Food and Agriculture Organization) of the United States, world pineapple production from 1999 to 2001 was 13,527,149 million tons and is estimated to be stable for 3 years World production has tripled in the last 30 years (3,833,137 in 1961 to 13,738,735 in 2001) The leading production countries in 2001 includeThailand (2,300,000 tons), the Philippines (1,571,904 tons) China (1,284,000 tons) The US is the largest pineapple importer from 1998 to 2000 with an average of 552597 thousand USD per year in canned, fresh and concentrated pineapple forms (Rohrbach et al., 2003)

According to statistics, the production of Smooth Cayene pineapple variety accounts for 70% of the world production and is mostly in canned form (about 95%) in so there has been pressure on investors to improve the Cayenne variety to provide a better form (Salewski and Scott, 2000)

Several studies on pineapples in the Vietnam

In Vietnam, according to research conducted by the Research Institute of Fruits and Vegetables, Cayenne have been gathered in our country including: Provinces with a large area of Cayenne pineapple such as Ninh Binh (700 ha), Nghe An (695 ha), Ha Tinh (438 ha), (Tuan and Tien, 2002) The origin of Cayene varieties grown in our country is usually imported from abroad and through crossbreeding (Tran The Tuc and Vu Manh Hai, 2002) Vietnam pineapple is a key fruit in processing export products, but the output is still very small compared to other countries in the region Raw materials supplied to processing plants are in a state of insufficient supply and demand due to the establishment of many pineapple processing factories with high capacity and modern technology such as An Giang, Ho Chi Minh, Can Tho

Acetic Acid Strain

Definition: Acetic fermentation is essentially the incomplete oxidation of ethanol to acetic acid under the action of bacteria Fermentation is “Effervescence” which is a biological process in redox reactions occur in microbial cells, in the absence of any oxidizing agents part of the organic matter is broken down to a reducing agent, the rest is broken down to an oxidizing agent [2] According to Pasteur's definition, fermentation is essentially an anaerobic process that occurs for the living activities of microorganisms to obtain energy (Mehaia and Cheryan, 1991; Tan, 2003)

The chemical formula of acetic acid is CH3COOH There is an OH group bonded with a CO group forming a COOH group, this group of COOH makes the molecule

Figure 2.2: Structure image of acetic acid 2.2.1 Characteristics of acetic bacteria

Nowadays, more than 20 species of bacteria capable of fermenting are collectively known as acetic bacteria (B2-2, B3-2, CN, C2, L2, LH1, VL2, K4, BD11, B2-3, KG1, NH2, CB, ST2.2, SKU) These bacteria are easy to find in the air, soil, water, juices, wine with low concentration, sugar solution easy to contact with air, easy to be slightly turbid, on the surface forming a thin surface, film thin smooth white gray or yellow

Pasteur assumed that the vinegar fermentation was caused by a bacteria belonging to the acetobacter or bacterium group Acetic bacteria not only oxidize ethyl alcohol to acetic acid, alcohol to acid, but they cannot oxidize methyl alcohol and higher alcohols In an environment with enough ethyl alcohol (5 - 13%), the main product is acetic acid At lower alcohol concentrations, Acetic bacteria completely oxidize alcohol to CO2 and H2O (Lương Đức Phẩm,1998)

Acetic bacteria are bacilli, non-spore forming, rod-shaped, oval, size: 0.8 * (1.0 -

3.0) àm, single, filamentous, chain, some spiral , spherical, bulging rods, club- shaped these bacteria have movable species by means of cilia, and species that cannot move The cells small they are Gram-, The cell old can change Grams The mostly catalase positive, oxidase free, often pigmented Some strains produce pink scum by Porphyrins [3]

Acetic bacteria belong to the aerobic group Their growth rate is very fast, from one cell after 12 hours can reproduce into 17 million cells.In the process of growth and development form acetic acid, low acid concentrations will stimulate their growth [5]

Acetic bacteria have the ability to assimilate different carbon sources such as:

Ethanol, glucose, fructose, saccarose, maltose, glycerin, lactose for the source of minerals and vitamins, it requires pantothenic acid and minerals (K, Ca, Fe, S, P ) to be assimilated

Acetic bacteria species grow in the temperature range from 20 - 35 O C At a temperature of 23-30 O C promotes them to reproduce quite quickly, resistant to highly acidic environments, some can grow at pH = 5.6 - 6.2, the optimal pH < 4.5 - 5.5, the characterized by their ability to change cell shape Under abnormal growth conditions, cells appear to be large and long filaments, swollen, or have strange shapes [7]

Currently, in the world more than 20 species of Acetic bacteria have been found in the world, collectively known as Acetobacter: A fairly large bacillus belonging to the obligate aerobic type, the temperature range for their growth is from 20 - 40 O C

Acetic bacteria belong to two genera Acetobacter and Acetomonas (cilia at the tip) Many types grown for a long time on the medium, easily give rise to special morphological forms (cells are enlarged or elongated, can branch) the widely distributed in nature, especially on food, fruits and air with yeasts on plant substrates

Here are a few species of Acetic bacteria with many practical implications:

- Acetobacter acetic: Short rod-shaped, non-spore forming, often joined together in long chains The cytoplasm was stained with iodine for yellow color This variety can grow at an alcohol concentration of 11% and accumulate in media up to 6% acetic acid, the optimum temperature for growth is 34 O C

- Acetobacter pteurianum: Short rod-shaped, dead cells stained with iodine for blue color

- Acetobacter orleameuse: Small rod-shaped, slightly pointed at both ends, develops into a thin, but firm film on the surface of the culture solution Iodine-stained dead cells give a yellow color This variety can grow in 10 - 12%V alcohol solution and produce 9.5% acetic acid

- Acetobacter xylium: The ability to form strong and sometimes quite thick films, this variety accumulates 4.5% acetic acid species is sometimes used with yeast to produce low-alcohol beverages

- Acetobacter curvum: 35 - 37 O C Raising this limit temperature, the variety grows weak and produces poor acid In fact, acetic fermentation is usually kept at a temperature of 32 - 34 O C for Ace bacteria Curvum

- Acetobacter suboxydans: This bacterium is widely used in the vitamin industry to produce ascorbic acid (vitamin C) Bacterial strains of suboxydans, acetic acid is accumulated and retained in the environment without further oxidation, Species with high oxidizing capacity that continue to convert acetic acid are classified 13% [8].

Overview of vinegar

Vinegar is produced from naturally fermented fruit, has the advantage that in addition to the main ingredient is acetic acid, there are other nutrients such as sugar, organic acids, amino acids, vitamins, inorganic salts , trace elements, etc are very good for consumers' health

Our country is a dense agricultural country with a humid tropical climate, so the source of fruits in our country is extremely rich such as: bananas, apples, mango, pineapples, The output of these fruit products remains unresolved contribute to the enrichment and diversification of vinegar products and also the consumption direction, the output for fruit products is the production of vinegar contains a lot of nutrients such as: fiber, antioxidants and phytonutrients in tangerine have a number of vitamins, amino acids

Present-day, the estimated potential market for fruit vinegar is quite limited because for-profit businesses often have no nutritional content, and may even be harmful to the health of users, so they produce vinegar From pineapple raw materials, this is an abundant and rich source of raw materials, solving the problem of output for fruit products, nutrients, and delicious taste (Chen et al., 2010; Horiuchi, Kanno, &

In 1864, chemist Louis Pasteur proved that vinegar is the result of natural fermentation, he figured out why wine becomes vinegar by the discovery of microorganisms that will turn wine into vinegar produced by fermentation of raw materials containing starch or sugar, or produced by preparation from refined acetic acid called vinegar fermentation b) Definition

Vinegar is an acidic liquid, formed from the fermentation of ethyl alcohol (C2H5OH), or from raw materials containing sugar or starch The main ingredients of vinegar are water and acetic acid (CH3COOH), the acid concentration is from 2 to 5%, the pH is from 4 to 5 Fruit vinegar is a product fermented from fruit materials containing sugar, water and acetic acid, fruit vinegar also contains many other acids, rich in amino acids, vitamins, inorganic salts and trace elements

Vinegar is divided into two types: Distilled vinegar and Mixed vinegar

Distilled Vinegar: (also known as rice vinegar) is the result of fermentation from raw materials containing starch and sugar Nutritional ingredients include acetic acid, sugar, organic acids, vitamins, inorganic salts, etc …

There are also several other types of vinegar:

- Wine vinegar: It is a product of the fermentation of a diluted pure alcohol solution of sour fermentation of grape wine juice, with the addition of inorganic salts and nutrients

- Rice Vinegar "Rice Vinegar": is the product of sour fermentation, the rice starch has been converted into sugar and then into alcohol

- Malt vinegar "Malt vinegar": It is the product of sour fermentation, the starch solution has been converted into molasses malt

Mixed vinegar: (chemical vinegar) is industrially produced by taking the refined acetic acid of the chemical component as the main raw material, adding dilute H2O to form it, without adding any other nutritional ingredients c) Chemical composition of fruit vinegar:

Fruit vinegar has a rich amino acid composition: 18 kinds of amino acids in the human body cannot be synthesized in vinegar, 8 amino acids that plants provide,in addition there are more than 10 types of acids: lactic acid, ketone-based acid, citric acid In fruit vinegar, there are vitamins B1, B2, C There are also trace elements::

Na, K, Ca, Fe, Cu, Zn, P d) Uses of vinegar

- Regulating and stabilizing the acidic and alkaline environment in the body:

According to nutritionists, vinegar is a physiological alkaline food through the process it produces an alkaline reaction Because the body daily absorbs a large amount of highly acidic foods such as meat, fish, eggs, etc., drinking or adding a little vinegar to food can neutralize the acidic environment

- Vinegar has anti-aging ability, limiting delaying the aging of the body, inhibiting and lowering the ability to form oxidized fat

- Eliminate Na + ions, inhibit excess salt in the body, thereby stabilizing blood

- Prevention of obesity: vinegar contains ammonium acid, in addition, vinegar also promotes the open metabolism in the body into a expendable form of energy e) Vinegar fermentation mechanism

Fermentation is the oxidation of alcohol to acetic acid, by acetic bacteria, under aerobic conditions

The general equation of fermentation is:

The reaction occurs in the bacterial cell For the reaction to take place, C2H5OH and O2 must be absorbed into the cell At that time, the oxidizing enzymes present in the cell of bacteria participate in oxidizing alcohol to form CH3COOH, which will exit the cell and dissolve in the medium solution

Figure 2.2 Oxidation of alcohol to acetic acid

In bacterial cells, oxidation occurs in a very complex way This process occurs in two stages The stages are summarized as follows:

Acetaldehyd CH3CHO + H2O CH3CH(OH)2

Hydrate acetaldehyd CH3CH(OH)2 + O2 CH3COOH + H2O

General procedure: C2H5OH + O2 CH3COOH + H2O In addition to the ability to oxidize alcohol to acetic acid, acetic bacteria also have the ability to participate in converting other alcohols into corresponding acids and other substances

- Metabolism of propyonic acid propyonic alcohol

- Metabolism of glycerin dioxyacetone alcohol

- Metabolism of lactic acid glucosenic acid

It should be noted that, during alcoholic fermentation, acetic bacteria will participate, the oxidation of acetic acid to CO2 and H2O to receive energy for its growth and development CH3COOH + 2O2 CO2 + H2O Therefore, after fermentation, it usually leaves an alcohol content of about 0.3-0.5% so that bacteria can use alcohol without using acetic acid as an energy source.

Fermentation techniques

In Vietnam, fermentation is the process of creating products by a certain volume of biomass with microorganisms Applying the following methods to improve skills and development determine the effectiveness of a method of producing acetic acid is the interface between oxygen of air and substrate with four methods of producing acetic acid by fermentation : a) Slow fermentation can refer to

This method is considered the traditional French fermentation method

The raw material of this method is grapes, the acetic acid bacteria used for the production process is Acetobacter orleaneuse

Procedure: During the fermentation process, people usually put 1/5 of the acetic acid into the fermentation tank with a capacity of ẵ barrel volume, continue to give the grape juice so that the entire volume reaches 2/3 of the volume of the fermentation tank The purpose of adding acetic acid is firstly to create conditions for fermenting bacteria to grow, on the other hand, to prevent other bacteria from growing, without being mixed with impurities, for fermentation at a temperature of 23-34 O C After a while on the surface will form a scum containing a lot of acetic acid

Therefore, oxidation is slow and ends after a few weeks the testing remaining alcohol, the vinegar will be removed and a new nutrient solution will be added If left for a long time, the quality of vinegar is rapidly degraded because the oxidation of vinegar occurs continuously fermenting, write the vinegar that grows to form a microbial network on the open surface, when it is shaken it will sink to consume the substrate without creating acetic acid Gradually, on the open surface, new bacterial gills are formed and the fermentation process continues the obtained vinegar usually contains 5-6% acetic acid to keep for a long time, it must be pasteurized Because of the limitation of three open surfaces, this method also has advantages: long fermentation time, low concentration of acetic acid, low yield b) Fast fermentation method

This method is practiced by the Germans on an industrial scale

This method creates a phase contact surface between the bed gas and microorganisms thanks to the addition of plate material in the device, so the productivity is higher This method is manipulated by watering the fermenter is filled with binder material and carries new bacteria on the surface The air goes in the opposite direction from the bottom to make the fermenter rapidly metabolized by bacteria, so the fermenter is high enough, the operation is well controlled, only the fermenter is too low once to get a thick vinegar at the bottom of the device In case the final fermenter contains a low amount of acetic acid, re-fermentation is carried out by pumping them back from the top c) Submerged fermentation method

In this method, the air escaping from the fermenter will form a magic in which the solid phase is bacteria, the solid phase is the wort in fermenters called acetators, the fermenters transfer changed

This method is applicable to anaerobic and aerobic microorganisms For anaerobic culture, the culture process does not require aeration, only stirring, and for aerobic microorganisms, it is necessary to continuously aerate the use of aqueous medium so that the surrounding surface is in contact with the liquid nutrients, they will grow vertically on the media column in microbiological technology to apply antibiotics, single-cell proteins, enzymes, amino acids, bread yeast production, etc pesticides, microbial products as fertilizers, etc…

The submerged fermentation method includes process characteristics and changes tracking based on microbial species and stages of fermentation so the choice of temperature is very important, but along with that is determining the time to maintain the process at a stable level, eliminating redundant time points as well as clearly defining time to properly stop the fermentation process to ensure product recovery and maximum yield

Through the above methods, the application of submerged fermentation to the research topic of pineapple vinegar needs to be carried out in order to study the influence and optimize the new processes to bring about constructive results as well as community as providing more choices for consumers d) Mixed fermentation method

This is a hybrid between the fast and the sinking methods This fermenter consists of two parts:

- The upper part like generator with filling buffer, works on the principle of fast fermentation

- The lower part (the part containing the fluid after passing through the binder) is fitted with an aerator to form an additional oxidation zone as an acetator in the submerged method

The oxygen supply through the aerator is stopped (when the power is turned off) there is still no effect on the bacteria because at that time the ventilation valves in the device are opened and air enters through natural ventilation, so the micro membrane bacteria on the mattress still do not die.This method overcomes the advantages and disadvantages of the two methods above

2.5 Techniques to pay attention to when producing vinegar:

Acetic bacteria usually digest very little nutrients, so nutrients need to be added to develop the ability to ferment at low levels.The propagation medium needs to be acidified to increase growth stimulation and inhibit other bacteria

In vinegar production, a certain amount of vinegar is added to the initial substrate to acidify the medium in order to: prevent the growth of harmful microorganisms, and put a certain amount of cells in the fermentation solution

Initial acidity can range from 2-6% According to a study by Eapen and Rao in 1979, the highest yield was obtained at an initial acidity of 2% Recent works show that to get higher acid content, fermentation is carried out at an initial acid concentration of 2-6% (Abrini et al., 1992) However, high acid content will limit the growth of bacteria and reduce the ability to ferment According to Henry, the initial acid concentration of 8% inhibited the activity of bacteria greatly The initial amount of acid required for activation is 2-2.5 (Nodes.E, 1986 ), 2% (Ebner, 1985)

2.5.2 Ethyl alcohol content in vinegar fermentation solution

Ethyl alcohol, like acetic acid, is an antiseptic against Acetobacter bacteria, it is used as a substrate Alcohol content can vary from 2 to 10% by volume, higher alcohol content will reduce fermentation yield Ebner (1985) and Heirich (1987) for ethyl alcohol use from 2 to 10% by volume The amount of ethyl alcohol maintained in the medium is always kept at 3-3.5% by volume (Nodes, 1986)

To avoid further oxidation to CO2 and H2O, an alcohol content of 0.2-0.5% by volume is required The amount of alcohol in vinegar inhibits the synthesis of oxidizing enzyme acetic acid and acetic salt (Dires, 1973)

In the study, no research was conducted on the percentage of alcohol affecting the pineapple vinegar fermentation, the determination by diluting the alcohol ratio with

METHOD

Objects, materials, time and place of research

Pineapple material used in the research is pineapple which was purchased at Tuc Duyen market, Thai Nguyen city

Table 3.1 Table of materials and equipment used in the study

Equipment Producing Country pH meter Switzerland

Table 3.2 Table of research chemicals used in the research

Enzyme pectinx Utra –SPL Australia

- The Acetobactor acetic astrain was obtained at the laboratory of the Department of Biotechnology and Food Technology, Thai Nguyen University of Agriculture and Forestry

Research on the production process of vinegar from pineapple in laboratory scale and production environment

Study time and place

From March 1, 2021 to October 20, 2021 Laboratory of Department of Biotechnology & Food Technology, Thai Nguyen University of Agriculture and Forestry

Research content

Research on the production of fruit vinegar from pineapple i Performing slow fermentation to determine the fermentation conditions of a acetic fermentation from pineapple

- Research to determine the amount of dry substance dissolving fermentation - Research to determine the conditions for acetic acid fermentation

- Reasarch to determine pH of fermented pineapple juice

- Research to determine the temperature of the fermentation process

- Research to determine the fermentation time of the fermentation process ii Evaluation of sensory quality criteria of products iii Developing a process to produce fruit cuttings from pineapples

- Evaluation of the quality of pineapple meat products

The product is evaluated for the limit of bacterial contamination in food according to QCVN 8-3: 2012 / BYT - National Technical Regulation on microbial contamination in food The product was determined microbiologically in food according to TCVN 4884-2: 2015 and Escherichia coli quantified according to TCVN 7924-1: 2008

1 Analysis of the composition and standard of benefits of the product product according to the national standard

2 Evaluation of the quality change of fruit vinegar products preserved under suitable conditions

3 Survey of demand and sensory evaluation of products: Conduct a survey of consumption and demand for fruit vinegar products and sensory evaluation of pineapple vinegar products with different formulations.

Research Methods

Pineapple vinegar products are made according to the following process:

Experiment 1 Research to determine the amount of dry substance dissolving fermentation pineapple

Determine the pH, temperature and fermentation time values to proceed to add sugar to the fermented fruit juice to determine the brix according to the ratios applied to the formulas in the following table:

Table 3.3 Table of experimental to determine the amount of dry substance dissolving fermentation pineapple

The fermentation temperature was fixed at 28 o C Celsius, pH = 5, and fermentation was carried out for 7 days during the monitoring process The fermentation process is monitored every 24 hours after 7 days to determine the amount of acetic acid based on the appropriate brix to choose and apply to the fermentation process

Based on the obtained experiments, conduct research for the next experiments

Experiment 2 Reasearch to determine the fermentation pH of pineapple juice

Fixed Brix of fermented fruit juice Fixed temperature at 28 o C Celsius and carried out fermentation for 7 days Conduct acetic fermentation to determine the appropriate fermentation pH Fermentation was monitored every 24 h After 7 days determine the content of acetic acid formula The experiment was carried out according to the formulas in the following table:

Table 3.4 Table of experimental layout to determine pH of fermentation pH Content Acid Acetic (%)

The results of the experimental set-up to determine the obtained pH will be fixed to conduct further research on experimental methods

Experiment 3 Study to determine the fermentation temperature of acetic acid fermentation.

From the results in experiment 1 determine the brix value and in experiment 2 fix the pH value

Carry out fermentation at the recipes with different process temperatures, then determine the acetic acid content in each recipe From the obtained results, the appropriate fermentation temperature for fermentation is selected Perform the experiment

Table 3.5 Table of experimental layout to determine fermentation temperature

The results of the experimental set-up for determining the temperature of the glaze will be fixed to conduct further research on experimental methods

The obtained research results will be fixed to conduct research in the next experiments

Experiment 4 Study to determine the fermenting time of acetic fermentation

From the results of experiments 1, 2 and 3, determine the brix value, determine the pH of the fermentation broth with fixed fermentation temperature

Carry out the fermentation of juice according to 5 different fermentation time formulas

The fermentation process was followed every 48 hours, then the acetic acid content was determined in each recipe From the obtained results determine the appropriate fermentation time for fermentation Perform the experiment according to the formula in the following table

Table 3.6 Table of experimental layout to determine the effect of fermentation time

Times (day) Content Acid Acetic (%)

Experiment 5 Assess the sensory quality criteria of the product

Then proceed to collect and process the data

Experiment 6: Building a process to produce fruit vinegar from pineapple On the basis of the results obtained in the experiments, proceed to develop a process to produce fruit vinegar from pineapple

3.4.2.1 Determination of soluble sugar concentration in fermented fruit juice

Use a Brix meter to determine the soluble concentration in the fermented fruit juice

Step 1: Basket of pure distilled water onto the prism surface Then through the eyepiece, you observe the line system If the blue background only goes to 0, then there is no need to recalibrate, if the blue background is not at 0 level, you use the adjustment screw to level 0 Normally, the brix meter has been calibrated at the place of manufacture, so the measurement results very accurate, but you should still perform this step regularly to check the machine's operation

Step 2: Basket a few drops of test sample onto the prism of the brix meter The test sample is liquid and has a temperature within the machine's temperature compensation limits for the most accurate measurement results Note that the test specimen must be evenly distributed over the surface of the prism

Step 3: Read the solution's sugar through the eyepiece, we can see the brix scale system can adjust the focus to see more clearly The white part represents the brix of the solution

Step 4: Clean the brix glucose meter Use soft paper to gently wipe the surface of the prism to clean the whole machine, leave the device in a dry place

3.4.2.2 Method for determination of fermentation pH

A pH meter to determine the fermented fruit juice, when measuring is done by inserting the tip of the electrode into the solution at least 30mm-50mm deep so that the permeable membrane can contact the solution, can be using 0.1N NaOH and 0.1N HCl to adjust the fermentation juice concentration to the required concentration Carry out the measurement, after collecting the results, wash the pH electrode with distilled water, do not rinse with solutions, solvents or alcohol, etc The pH electrode must be preserved by adding a few drops of 3M KCl to the plastic cap attached at the bottom electrode tip

3.4.2.3 Method for determination of acetic acid content by the method of determining total acid content

Perform: Take 10 ml of the fermentation broth and place it in a conical flask

Add 2-3 drops of phenolphthalein and titrate with 0.1N NaOH with the burette until the solution turns a light pink color that persists for about 30 seconds

Calculate the result: Acetic acid concentration = K.a.100% (%) b

K: is the number of ml of 0.1N NaOH needed to titrate is the number of ml of sample solution used for titration is the coefficient of acetic acid, K acetic acid = 0.006

3.4.2.4 Method to determine the concentration of acetic bacteria

Principle: Based on colony counting method Using the pour plate technique, count colonies on agar after aerobic incubation at a temperature of 30-34 degrees for 48-72 hours The number of aerobic bacteria in 1 ml of the test food product sample was calculated from the number of colonies counted from the culture cartridges according to the dilutions

Prepare the environment, chemicals: LB medium: Tryptone:10g, salt: 5g, Yeast extract: 5g, H2O: give enough 1000ml, adjust the pH of the medium from 7.5-8, H2O to get 1000ml The autoclaved medium was sterilized at 121 o C for 20 minutes

Diluent: use sterile physiological saline or distilled water Proceed:

- Sample dilution: perform sample dilution until the required dilution is obtained

- Each dilution uses 2 petri dishes and 1 separate pipette (at least 2 dilutions) - Take 0.05 ml of diluent at different dilutions and put it in the middle of each petri dish containing nutrient agar, and spread evenly on agar

- Turn the plate upside down and culture in an incubator at a temperature of 30- 34 degrees Celsius for 48-72 hours for official results Calculate the result, after colony growth, count the colonies growing on the plates

The average number of bacteria present in 1ml of sample was calculated by the formula: N ( colony/g or ml ) Inside : total number of colonies counted on all plates n1: number of plates at first dilution n2: number of plates counting at second dilution f1 : dilution factor of the 1st counter plate v: volume of inoculum in each petri box

3.4.2.5 Methods for assessing sensory quality

The scoring method to assess the sensory quality of the product Set up a sensory panel of 07 people to evaluate sensory quality After testing the product, the council will evaluate the intensity of each sensory indicator by giving a score The sensory scale is built according to Vietnamese standards ( TCVN 3215 - 79 )

RESULT AND DISCUSSION

Research results

4.1.1 Research results to determine the amount of dry substance dissolving fermentation pineapple

The content of brix value determined on fermented fruit juice is a necessary parameter because of the effect on the acetic acid of the product, so I performed the experiment according to 5 different formulas fixed at 28 o C Celsius C, pH = 5.5 and fermentation time for 7 days to determine the most suitable amount of soluble solids CT3 = 6

Table 4.1 Research results to determine the amount of dry substance dissolving fermentation pineapple

Figure 4.1 Results showing the influence the amount of dry substance dissolving fermentation pineapple

The results obtained in Table 4.1 and Figure 4.1 show that the acetic acid content tends to gradually increase from the initial minimum brix of 5 to the brix = 6 with the largest acetic acid content Continuing to increase the brix = 6.5 and brix = 7, the acetix acid content tends to decrease

At brix = 5 brix, the smallest acetic acid content is 0.21 (g/100ml) Increasing the brix degree to 5.5 degrees brix, the acetic acid content is 0.286 (g/100ml) increasing by 0.076 (g/100ml) After increasing the brix = 6, the acetic acid content increased significantly from 0.286 (g/100ml) to 0.465 (g/100ml), which is one and a half times increase of 0.179 (g/100ml) compared to the acetic acid content at the previous brix degree

Continue to increase brix = 6.5 acetix acid content tends to decrease specifically from 0.465 (g / 100ml) to 0.348 (g / 100ml) ie 0.12 (g / 100ml) the further increasing the brix level to 7, the acetic acid content continued to decrease from 0.348 (g/100ml) to 0.268 (g/100ml) ie 0.08(g/100ml)

From the above comments, the indicator of fermentable sugar content is suitable for the growth of acetic acid bacteria because at low content bacteria will be difficult to grow, high content will limit the growth of this bacteria directly limit the maximum

Content Acid Acetic growth rate, therefore, choosing the best growing bacteria at brix = 6 will help to achieve the highest level of acetic acid, conduct research for further experiments

4.1.2 Research results to determine the suitable pH for fermentation pH for fermentation The initial pH has a great influence on fermentation

Experiments were carried out according to 5 different recipes, fixed at 28 o C, fermentation for 7 days to determine the initial pH of the most suitable fermented fruit juice

Table 4.2 The research results determine the suitable pH pH Content Acid Acetic(%)

Figure 4.2: Results the determine the suitable pH

Table 4.2 and Figure 4.2 show that, when the pH changes, the acid content also changes The initial acetic acid content tends to increase from the smallest pH of 4.5 to the maximum at the most suitable pH of 5.5; then tended to decrease and the lowest acid content at the highest pH was 6.5

At pH = 4.5, the acetic acid content is 0.52 (g/100ml) Increasing the pH to 5, the acetic acid content increased insignificantly, 0.062 (g/100ml) When increasing the ratio 5.5, the acid content reached the highest level, increasing 0.127 compared to the initial PH value

The increasing the degree to the ratio of 6 and 6.5, the acetic acid content tends to decrease Because the highest acetic acid is 5.5 = 0.647 (g/100ml), when the ratio is increased to 6, the acetic acid content decreases to 0.516 (g/100ml), the lowest acetic acid content is at the rate of 6.5 down to 0.385 (g/100ml)

Through Table 4.4 and Figure 4.3, we can see that, when the PH ratio changes, the acid content will change accordingly The initial acetic acid content tends to be the smallest at the rate of 4.5, increasing to the most suitable maximum of 5, then a decreasing trend will appear At pH = 5.5, the highest concentration was 0.647

(9g/100ml) and as the pH increased, the amount of acid decreased significantly at pH 6.5, the content was only 0.385 (g/100ml)

From the table, it can be seen that when the pH changes, the acetic acid content also changes, and the acetic acid content tends to increase from the smallest pH of 4.5 to the maximum of 5.5 and then to decrease deeply Therefore, it can be seen that at a low pH, Acetic bacteria grow at a normal level, so when the pH is too high, it will limit the growth of bacteria for low acetic acid content Therefore, determining the pH

= 5.5 is the most suitable content of acetic acid generated at the highest level, conducting research for further experiments

4.1.3 Research results determine the suitable fermentation temperature for fermentation

The fermentation temperature of fermented fruit juice is an important indicator, having a great influence on the fermentation process So I experimented with 5 different recipes, The dilution of alcohol at a rate of 5% is to optimize the steps in the study of the process fixed at 28 o C, pH = 5.5, fermented for 7 days to determine the most suitable fermentation temperature

Table 4.3 Research results determine the suitable fermentation temperature for fermentation:

Figure 4.3 Results the determine the suitable fermentation temperature for fermentation:

Through the above research results, it is found that temperature is an important factor that greatly affects acetic bacteria Acetic bacteria will stop growing and may die if the temperature is too low or too high In the appropriate temperature range, bacteria can sustain life and produce a certain amount of acetic acid

A big difference can be seen at temperatures of 24 o C and 32 o C Celsius because the acetic acid content creates a difference because the measured content is low in the upper temperature range At 28 o C Celsius, the acetic acid content is the lowest 0.325 (g/100ml) The temperature will limit the growth of bacteria so the metabolism will not take place optimally At temperature at 32 o C, the acetic acid content produced at 0.285 (g/100ml) is both low and costly, along with the largest concentration of acid acid at the temperature of 28 o C is 0.480 (g/100ml) )

Choosing a fermentation temperature of 28 o C is suitable for pineapple vinegar fermentation, fixed to conduct further experiments

4.1.3 Research results determine the appropriate fermentation time for fermentation

The fermentation time of fermented fruit juice is an important indicator, which directly affects the fermentation process So I conduct experiments according to 5 different formulas, fixed at 34 o C, brix = 6, determined pH = 5.5, monitoring fermentation time will determine the target and avoid waste progress

The results obtained from the study are shown in Table 4.3 and Figure 4.3 below:

Table 4.3 Research results determine the appropriate fermentation time for fermentation:

Time (day ) Content Acid Acetic (%)

Figure 4.3 Research results determine the appropriate fermentation time for fermentation

According to Table 4.3 and Figure 4.3, on the 10th day of fermentation, the acetic acid content was 0.42 (g/100ml) to the 20th day of fermentation, the content increased by 1.6 (g/100ml) and nearly doubled 1.18 times (g/100ml) After increasing the follow-up time to the 30th day, measuring 2.48 (g/100ml) increasing by 0.88 (g/100ml) to the 40th day of fermentation, the highest acetic acid content reached 4 (g/100ml)

Data processing method

“Building a research process to produce fruit vinegar made from pineapple” - -

- Cleaning: Clean, peel, select standard ingredients such as not mushy, fragrant, remove unsatisfactory fruits such as bruises, worms and then wash with clean water

- Peel: Use a sharp knife to cut off the 2 ends of the fruit and then peel the skin to remove all the fibers on the surface of the banana, remove calluses, stamp

- Thin cutting: 2mm thin cutting The purpose of the fruit is to cut into small pieces, break up the whole tissue, secrete fluid, create favorable conditions for the following process

- Enzyme treatment: After sliced raw materials are treated with enzyme pectinex Ultra SPL 0.15% for 20 minutes The aim is to hydrolyze the pectin content in the fruit pulp and the cellulose in the cell wall to facilitate juice recovery

- Mixing Fruit: The juice will be added with water and diameter to create the right amount of juice for the fermentation process to form the following products:

- The raw material/water ratio is 1:2, the sucrose mix measures the dissolved solids content of 6 o Bx

- Fermentation: Fermentation at pH 5.5, temperature 28 o C for 20 days The purpose of fermentation is to convert starch into vinegar and some finished products

- Filtration: Filtration in the performance purpose is to remove the residues left in the fermentation process, to obtain the final product.

CONCLUSION AND SUGGESTION

Conclude

- The optimal the amount of dry substance dissolving fermentation to be 6 o Bx - The optimal pH value was determined to be 5.5

- The optimum fermentation temperature was determined to be 28 o C

- The optimum fermentation time was determined to be 20 days

- Researched and introduced the production process of fruit vinegar from pineapple

Request

Because to the short internship period, the factors affecting the fermentation process have not been fully studied The shelf life of the product is yet to be determined The process of implementing the project only took place in a short time, so there were no time to find out the tastes of consumers, so the research and evaluation of product quality was only within the laboratory

Limitations to time and equipment limitations, although we have tried to complete the study, there are still many shortcomings The product following suggestions: Conduct research on processing and production of fruit vinegar with other ingredients, research the shelf life of the product, research by kinetic fermentation method, research on vinegar production equipment an industrial scale

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