Nutritional food technology is the engineering and method of processing raw materials into semi-finished products or processing raw materials and semi-finished products into food, which includes the processing steps or all processes required from raw materials to finished products or to transform ingredients into final consumer goods.
Nutritional food processes are linked to raw materials and products, and each product has a corresponding process.
That is, the processing of a raw material into a product, which involves what processing methods or unit operations are used, how many processing methods or unit operations are required, and how these processing methods or unit operations are combined;
From raw materials to finished products there may be a variety of ways, specific to each process, depends on the purpose and requirements of food processing, according to different food requirements can choose the corresponding unit operation, different unit operations constitute different processing technology;
In some cases, processing from raw materials to food is a one-step transition, and in some cases, the number of processing transition steps is increasing.
The processing steps that combine one or more of these unit operations organically and reasonably are a complete food processing process.
The process is composed of different processes, and the production of products generally goes through several processes.
Nutritional food technology determines the quality of processed food. The quality of the food depends on the rationality of the process and the processing technology used in each process.
Each process can be implemented using different techniques.
The application of different technologies will result in different product quality, which is considered to be the core of food technology.
The research and development of nutritional food needs to go through the research and development process of small trial, pilot trial and small batch pilot production.
Many people engaged in the research and development of nutritional food have had such experience, has done a very good test in the laboratory, to the production site for pilot test or small batch trial production of the product status is far from the envisaged state.
It’s very frustrating; There are also some researchers who have very good research results in the transformation of results there are some unsatisfactory “accidents”.
Tasks at all stages of the development process
1. Make a small trial
The pilot is based on the theoretical research results of the laboratory, the preliminary design, the amplification of a certain multiple, and the production under the conditions of the laboratory, the requirements for the equipment are not strict, and some can be replaced by the same type of devices, which is small in scale and easy to operate.
The corresponding technological parameters and theoretical basis are obtained to prepare for the pilot test in the future.
2. Pilot scale test
Pilot trial refers to the process of large-scale pilot production, trial marketing and trial use in order to make the research results industrialized, reduce the transformation risk and increase the conversion rate.
After the pilot test is mature, the pilot test is carried out to study the industrial production process and equipment selection to provide a basis for industrial design.
The purpose of this process is to verify, improve and perfect the experimental results, eliminate various uncertainties, obtain reliable data, and make it match with other related technologies, in line with the actual production, and consistent with social needs, so that the new technology is successfully applied to the production, and the new product is successfully introduced to the market.
3. Small batch trial production
Small batch pilot production is the necessary transition link from small experiment and pilot test to industrial production.
Before mass production, arrange to use all formal production tools, processes, devices, environments, facilities and cycles to produce appropriate small batch quantities of products to verify the rationality of product design and product manufacturability.
Formulation and technology of nutritious food
(1) Overview of nutritional food formula design
The so-called formula design is based on the performance requirements and process conditions of the product, through testing, optimization, evaluation, reasonable selection of raw and auxiliary materials, and determine the dosage ratio of various raw and auxiliary materials.
How to develop a new product, how to design a new formula, is crucial to the enterprise.
To design a good food formula and become a truly excellent technician, you must have solid basic skills.
(2) What basic skills are required for formula design
Each raw material has its own characteristics, you can only use it well if you are familiar with it and understand it.
In different formulations, according to the requirements of different performance indicators, it is very important to choose different raw materials.
②. Familiar with the characteristics and use of nutritional food additives
Food additives are the most widely used in food production, the most creative field, it plays a pivotal role in the development of the food industry, known as the soul of the food industry.
Understanding the various properties of food additives, including compatibility, safety, stability (heat resistance, light resistance, microbial resistance, resistance to degradation), solubility, etc., is an important matter for formulation design.
③. Familiar with equipment and process characteristics
Familiar with the equipment and process characteristics, it is beneficial to formula design without harm;
Only in this way, in order to play the best effect of the formula, is a real mature technology.
For example, spray drying and freeze drying, sandwich pot cooking and microcomputer controlled vacuum cooking, three-dimensional mixing and kneading mixing, different equipment leads to different processes and formulas.
④. Accumulate process experience
Not much description, pay attention to the process, pay attention to the accumulation of processing technology experience.
Just like a good dish, the ingredients are important, but the cook’s cooking is equally important.
The same formula, not the same process, the quality of the product is very different, which needs to be summarized and refined.
⑤. Familiar with experimental methods and test methods
The commonly used experimental methods in formulation research include single factor optimization, multi-factor transformation optimization, average test and orthogonal test.
A qualified formula designer must be familiar with experimental methods and test methods, so that he will not be at a loss to face a pile of experimental data after the completion of the experiment.
⑥. Proficient in consulting various literature materials
Many students and teachers in school attach great importance to consulting various literature, and specific production enterprises rarely do so.
Now the Internet is very developed, you can generally find what you need.
Looking up literature does not waste your valuable time, it can save your valuable time, because what you see is some indirect experience.
Through searching and collecting information, configuring the proportion of raw materials and adjusting the sensory evaluation, we design our own product formula.
⑦. Do more experiments and learn to summarize
Only theoretical knowledge, no specific experimental experience, can not make a good product.
Do more experiments, don’t be afraid of failure, and keep a record of each experiment. Keep a detailed record of your successes and failures and develop this habit.
Learn to summarize the data and experience of each experiment.
Good at summarizing the experimental data each time, find out their rules, can guide the experiment, get twice the result with half the effort.
⑧. Integrate resources
Formulation designers should consider formulation design as a systematic process, and design is not only the design itself, but any factors related to design that can promote development need to be considered.
Designers should not just work behind closed doors in the lab, but “push the two walls” : Internally, they should tear down the walls between departments within the company and establish connections with people in the industry.
When ideas change, the world changes.
Only through the dissemination of knowledge, exchange of experience and other methods can we trigger innovative ideas, stimulate innovation enthusiasm, and enhance the ability to absorb, transform and innovate.
Seven steps to nutritional food formulation design
The formula design of nutritious food is based on the process conditions and performance requirements of the product, through testing, optimization and evaluation, reasonable selection of raw and auxiliary materials, and determine the ratio relationship between the amount of various raw and auxiliary materials.
Nutritional food formulation design is generally divided into seven steps:
- 1 is the main skeleton design
- 2 is the color design
- 3 is the fragrance design
- 4 is the seasoning design
- 5 is quality improvement design
- 6 is anti-corrosion preservation design
- 7 is functional nutrition design
1. Main frame design
The main skeleton design is mainly the selection and configuration of the main raw materials to form the initial form of nutritious food.
The main raw material of the main skeleton design of nutritious food is based on the categories and requirements of various foods, which gives the main components of the basic skeleton of the product and reflects the function of the nature of the food.
The selection of the main raw materials must meet the requirements: hygiene and safety, nutrition and digestibility, storage resistance, neat appearance, good flavor, food convenience and speediness.
In the actual design process, the quantification of the main raw materials usually adopts the backward method, the addition amount of the main raw materials is set first, and the addition amount of other auxiliary materials is determined on this basis.
For the specific proportion of the main raw materials in the food, it can be determined after the final formula design is completed. The key to the quantification of the main raw materials is to deal with the proportion of the main raw materials and auxiliary materials.
2. Toning design
Nutritional food pay attention to color, aroma, taste, shape, the first is the color.
As an indicator of food quality, food color is paid more and more attention by food research developers, manufacturers and consumers, and color design plays an important role in food processing and manufacturing.
In the color design, food coloring, hair color, color protection, fading is the key research content of food processing.
Nutritional food color design should pay attention to the following points:
- (1) Use colorants that comply with relevant regulations
- (2) Select the appropriate food colorant according to the physical properties and processing technology of the food;
- (3) According to the form of food, choose the appropriate addition form;
- (4) According to the sales area and national habits of nutritious food, choose the appropriate color form and color;
- (5) The toning method of nutritious food should be carried out in strict accordance with the provisions of the State on colorants; Control food processing technology.
3. Fragrance design
Aroma design is to match the aromatic substances together, due to the different volatilization of each aroma component and the staged volatilization, the aroma type is constantly changing, and the olfactory nerve is stimulated in order to avoid olfactory fatigue, so that people can feel the beauty of the aroma for a long time.
The flavor design of food is based on the characteristics of various flavors and spices combined with the phenomenon of taste and smell, to achieve the balance between aroma and flavor, in order to seek the harmonious beauty between various aromas and spices.
The aroma of food should not only effectively and properly use the adding technology of food flavor, but also master the technology of food processing and manufacturing and cooking.
The main points of use of food spices are as follows:
- (1) Be clear about the purpose of using spices;
- (2) The amount of spices should be appropriate;
- (3) The aroma and taste of nutritious food should be coordinated;
- (4) Pay attention to the impact of spices on the color of nutritious foods;
- (5) The aroma of spices should not be too new;
4. Seasoning design
The seasoning design of nutritious food is to produce people’s favorite taste through the scientific preparation of raw materials and condiments in the process of food production.
The process of seasoning design and the overall effect of taste have an important relationship with the raw materials selected, but also with the collocation of raw materials and processing technology.
The rules of seasoning design should be mastered in the process of seasoning design of nutritious food.
Master flavor enhancement, flavor multiplication, flavor cover-up, flavor transformation and flavor interaction;
Master the characteristics of raw materials, choose the best time, use the appropriate seasoning method, remove one, highlight the positive taste, enhance the aroma and delicious food, in order to modulate the taste of more, bright color, good texture, nutrition and health of the flavor.
In the actual seasoning design of nutritional food, we must first determine the flavor outline of the main flavoring, according to the flavor intensity of the original accessories, and consider the factors that produce umami in the process of processing, and determine the corresponding amount of use within the cost range.
Secondly, it is also necessary to determine the fragrance balance of the spices combination, in general, the lighter the main fragrance, the less spices are needed, and according to the intensity and intensity of the aroma of the main fragrance modification.
Seasoning is a very fine and subtle work, in addition to the need to understand the nature of seasoning and seasoning, relationship, change and combination, seasoning procedures and a variety of seasoning and seasoning use time, seasoning design to strive to make food seasoning do “thick and not greasy”, strong taste, not greasy, both to highlight the flavor, but also to get rid of raw material odor, But also to maintain and enhance the delicious raw materials, to achieve the tree taste, add flavor, wide taste effect.
5. Quality improvement design
Quality improvement is a quality improvement design for changing the texture of nutritional food on the basis of the main body skeleton.
The quality improvement design is to give the food a certain form and texture through the combination of nutritional food additives to meet the quality and process performance requirements of nutritional food processing.
The quality improvement design of nutritional food is based on the design of the main body skeleton, the purpose is to change the texture of food.
Nutritional food texture is another important property of nutritional food in addition to color, aroma and taste, it is difficult to control factors in the processing of nutritional food, but also one of the most important key indicators to determine the grade of nutritional food, it is related to the basic composition of nutritional food, organizational structure and temperature, nutritional food texture is an important aspect of food evaluation.
Nutritional food quality improvement design is improved through production technology; Another is to improve through formula design, which is one of the main contents of nutritional food formula design, the main ways of nutritional food quality improvement design are thickening design, emulsification design, moisture retention design, bulk design, catalytic design, oxidation design, anti-knot design, defoaming design.
6. Preservative preservation design
Nutritional food formula design after the main skeleton design, color design, flavor design, flavor design, quality improvement design, color, aroma, taste, shape have, but such product shelf life is broken, can not achieve the maximum economic benefits of the product, but also need to carry out anti-corrosion preservation design.
The main goals of modern nutritious food processing are:
- (1) Ensure the safety of nutritious food processing
- (2) Provide high quality products
- (3) Make nutritious food easy to eat
Microbial and chemical factors may cause food spoilage and deterioration, which is the main reason affecting the safety of nutritious food. For processed nutritious food, its usually dominated by microorganisms;
The quality of nutritious foods, such as flavor, color and texture, is also closely related to spoilage caused by microorganisms, enzyme action and chemical reactions.
It is necessary to clearly understand the main factors causing food spoilage and its characteristics in order to better control them and achieve the purpose of modern food preservation.
The main factors that cause the spoilage of nutritious food include internal factors and external factors. The external factors mainly refer to biological factors, such as microorganisms and pests in the air and soil.
The internal factors mainly include the enzyme action of food itself and various physicochemical effects.
Common methods of preservation and preservation of nutritional food:
Low temperature preservation technology, food drying preservation technology, addition of preservatives, canning preservation technology, microwave technology, packaging technology (vacuum packaging, air conditioning packaging, pallet packaging, active packaging, antibacterial packaging), fermentation technology, irradiation preservation technology, ultrasonic technology, etc.
Preservative preservation of nutritional food is a systematic process, with the deepening of research on preservative preservation of nutritional food, the theory of preservative preservation has a new understanding, researchers believe that no single preservative preservation measures are perfect, must adopt comprehensive preservative preservation technology, the main theoretical basis is:
Fence technology, good practice, hygienic standard operating procedures, hazard analysis and critical point control, predictive microbiology, food traceability systems and others.
7. Functional nutrition design
Functional design is to add specific functions on the basis of the basic functions of nutritional food to become functional food.
Nutritional foods classified according to scientific and technological content, the first generation of products called fortified foods, and the second and third generation of products called health foods.
Food nutrition fortification is the process of adding one or more nutrients or some natural food ingredients to food to improve the nutritional value of food according to the nutritional needs of different people.
Fortified food has many advantages, in some foods to strengthen the necessary nutrition of the human body can not only improve the value of nutrients in food, but also enhance the body’s bioavailability of nutrients, is to improve people’s nutritional status is both economic and effective way.
In the production process of fortified food, attention should paid to nutrition, health, economic benefits and other factors, and combined with the specific situation of each country and region to strengthen food.
The main methods of food nutrition fortification are:
- (1) Added to raw materials or essential foods;
- (2) Added during processing;
- (3) Added in the last process of processing.
Food fortification should follow the principles:
- (1) Strict implementation of regulations
- (2) According to needs
- (3) Balanced nutrition and easy absorption
- (4) Process rationality
- (5) Economic and reasonable
- (6) Maintain the original flavor of food
- (7) Pay attention to the retention rate of nutritional fortifiers. Many nutrient fortifiers easily affected by light, heat, oxygen and so on and are unstable, which will cause a certain amount of losses during food processing and storage.
Sweetener flavoring
1. Defects of single sweeteners
(1) Safety, quality, process, cost, these four factors promote the use of sweeteners to become an inevitability.
A single sweetener that can fully meet these requirements does not currently exist.
In fact, many synthetic sweeteners are different from sucrose in taste and taste, and there is always a bitter taste after eating.
The lingering taste always has a metallic taste, such as saccharin, cyclamate, etc.
Many synthetic sweeteners are good at low concentrations, but once the concentration of aqueous solution increased, the sweetness decreases and the taste deteriorates, from sweet to bitter, such as AK sugar.
(2) There are some synthetic sweeteners that are not resistant to high temperatures.
It is not able to withstand the storage time, and the sweetness will weakened when the storage time long.
For example, sucralose, which recognized as having a sweetness similar to sucrose, will weakened and decreased after 2 years of storage.
What’s more, there is no synthetic sweetener that delivers the full-bodied, sweet taste of sucrose.
In other words, all synthetic sweeteners show a simple, not thick sweet taste, sweet taste is not mellow.
Most of the natural sweeteners natural glycosides extracted from herbs and fruits. From the perspective of production resources, sweetness multiple, sweetness thickness and price factors, stevia has the most promising application.
The bitter taste of stevia has always affected its promotion, but it has been unable to get rid of its inherent glycoside grass taste, and can only used as a sweetener auxiliary material. The same is true for momorrhodoside.
Not only the taste of a single sweetener is always inadequate, but also the physical and chemical properties of a single sweetener and the limitations of the amount of addition and price make the addition of a single sweetener can not achieve satisfactory results.
2. The purpose of combining sweeteners
Compounding is the use of the synergistic effect between various sweeteners and the physiological characteristics of taste to achieve the following purposes.
- (1) Reduce bad taste and increase flavor;
- (2) Shorten the beginning of the taste of poor taste;
- (3) Improve the stability of sweetness;
- (4) Reduce the total use of sweeteners and reduce costs.
3. Type of compound sweetener
In actual production applications, there are mainly three categories of compound sweeteners.
The first category is the compound sweetener, which is a base ingredient for the sweetness of synthetic sweeteners, which is low in cost and can barely meet the basic requirements of the taste of food sweetness.
The second category is based on synthetic sweeteners as the main base ingredient of sweetness, supplemented by natural sweeteners.
The third category is all to a natural sweetener as a sweetness base ingredients, the use of high-tech and supplemented by other natural sweeteners for sweetness synergistic ingredients, and even other auxiliary food additives are all natural extracts.
The use of whole natural ingredients, in line with today’s natural, healthy, green, slimming sweetener fashion trend.
4. Examples of sweetener compounding
(1) Compound sweetener
It can give full play to the best effect of sweeteners and reduce costs.
It can not only maintain the special function of a single sweetener, but also lead to the composition of new flavor additives and the composition of new compound sweeteners, by using the synergistic effect and physiological characteristics between various sweeteners, it can reduce the bad taste, shorten the poor taste at the beginning of taste, improve the stability and mellow sweetness, reduce the total use of sweeteners, and reduce the cost.
(2) Take fructose, for example
A 10% mixture of fructose and sucrose is 30% sweeter than a 10% solution of sucrose.
In soft drinks, if several sweeteners used together at the same time, the cost can reduced by up to 40% or so. The combination of sucralose and other sweeteners has a very obvious effect, such as fructose, glucose, maltose, sucrose, lactose, xylitol, especially in soft drinks, sucralose and fructose are very effective.
Fructose has its special flavor and pleasant taste, and the combination of them not only greatly reduces the calories in the drink, but also reduces the amount of sucralose and fructose to the desired level.
(3) acesulfame
(AK sugar) and other sweeteners combine to produce a strong synergistic effect.
The general concentration can increase the sweetness by 20%-50%.
When the sweetness of AK sugar and aspartame is 1:1, the sweetness immediately increases to 300 times, and the stability of aspartame will greatly increased.
It is the best compound sweetener at present, and the sweetness effect of AK sugar and cyclamate is also very obvious.
(4) stevioside
In addition to being used in food alone, it can also mixed with other sweeteners to achieve more satisfactory results.
Compound sweeteners actually have a variety of choices, of which “erythritol sucralose” is now the new favorite of most companies, erythritol sweetness is about 70%-80% of sucrose, sucralose is about 400-600 times of sucrose, the two according to a certain proportion of the composite index reflects well.
All sweeteners and sucrose have taste differences, added high-intensity sweetener food and added sucrose food taste is not the same, mainly due to its time, strength characteristics and their aftertaste.
It should taste sweet, mellow and pure like sucrose.
Only by taking the road of compounding sweeteners, only the synergistic compounding effect can make the sweetener close to the mellow taste with sucrose sweetness.
In the combination of sweeteners, people often choose a compound way of “high sweetener + sugar alcohol”, which can make the advantages of these two types of sweeteners complementary:
High sweetener sweetness is relatively high, small volume, small amount, there is a certain bad taste, sugar alcohol sweetness is relatively low, there is a certain volume, some can cover up the bad taste of high sweetener.
Acesulfame mixed with sucrose and sorbitol for excellent taste.
Erythritol has a larger heat of solution, and solid foods and candies made with it have a more distinct cool feeling.
Erythritol is sweet and refreshing because the combination of other higher sweeteners such as protein and sweet glucose can effectively mask the bitter taste of these sweeteners.
(5) Heat treatment
Heat treatment is the most common process in food production, and the maximum temperature has a great influence on the pyrolysis and hydrolysis stability of sweeteners. The PH level also affects the stability of the sweetener.
The above factors will even damage the unstable sweetener and reduce the sweetness of the product, so it is necessary to choose different sweet to cooperate with and improve its stability.
For example, AK sugar and cyclamate are heat-resistant and can used together.
Aspartame has poor heat resistance, but aspartame and AKose have a synergistic effect when combined at a ratio of 1:1.
Practice has proved that the use of compound sweeteners can obtain satisfactory taste, longer shelf life, better economic benefits, and give commodity producers more freedom of choice.
So many of the sweeteners we use not single, but made up of a combination of ingredients.
Mechanism, intensity and characteristics of sour taste
The sour taste of the acid agent the sensation caused by the stimulation of hydrogen ions on the mucosa
So the substances that can ionize hydrogen ions in solution are all sour substances.
Acidity is not measured by PH alone.
There is no simple correlation between the intensity of acidity and the taste of acidity.
Various sour agents have different acid sensations, and the acid sensations they cause in the mouth are related to the type of acid radicals, PH, titrable acidity, buffer solutions, and the presence of other substances, especially sugars.
At the same PH value, organic acids are more acidic than inorganic acids. But the duration of the sour taste is not proportional to the PH level.
The acid taste with slow dissociation rate lasts longer, and the taste of acid substance with fast dissociation rate disappears quickly.
Sour taste is not only related to hydrogen ions, but also affected by anions of sour agents.
The anions of organic acids easily adsorbed on the tongue mucosa, neutralizing the positive charge in the tongue mucosa, making it easier for hydrogen ions to contact the tongue taste buds, while the anions of inorganic acids are easy to combine with the proteins of the oral mucosa, and have a passivating effect on the perception of sour taste.
Generally speaking, at the same PH value, the acidity intensity of organic acids is greater than that of inorganic acids. Due to the different adsorption capacity of different organic acids anions on the tongue mucosa, the acidity intensity is also different. For example, for acetic acid, formic acid, lactic acid and oxalic acid, under the same PH value, the acidity intensity is as follows: acetic acid > formic acid > lactic acid > oxalic acid.
At the same concentration, the acidity of various acids is also different, mainly due to the effect of the anion dissociated by the acid agent on the taste.
The sourness of one acid cannot completely replace the sourness of another acid with equal mass or concentration.
The acidity intensity of different acids compared at the same concentration in the following order: hydrochloric acid > nitric acid > sulfuric acid > formic acid > acetic acid > citric acid > malic acid > lactic acid > butyric acid.
The anion of the sour agent has an effect on the flavor of the sour agent, which is mainly due to the number and location of the hydroxyl, amino and carboxyl groups of the anions.
The sour taste of lactic acid and tartaric acid is accompanied by astringency;
For example, the sour taste of citric acid, ascorbic acid and gluconic acid is refreshing, and the sour taste of malic acid is astringent bitter.
The sour taste of acetic acid has a pungent odor;
The sour taste of glutamic acid has a salty taste.
1. Compound seasoning of organic acids
The compound seasoning of sour agents usually refers to the combination of organic acids, and their sour intensity and taste quality have their own characteristics.
After the combination of different sour agents, the sour characteristics of the single sour can adjusted and reduced, which can used to adjust the taste, sour sensitivity and taste development speed, so as to give the food different sour flavor styles.
Different acids produce different pleasurable sensations, as citric acid, ascorbic acid, and gluconic acid produce a pleasant and refreshing sour taste, but the sour taste disappears quickly.
Malic acid produces a slightly bitter sour taste, and its sour taste produces and disappears more slowly than citric acid.
Phosphoric acid and tartaric acid have weak astringency, acetic acid has strong irritant, and their sour taste disappears quickly.
Fumaric acid has a strong astringent taste and can taste sour for a long time.
Phosphoric acid provides a distinctive sour taste in colas.
Due to the existence of these differences, it provides a broad prospect for the compounding of sour agents.
2. The main consideration of the compound seasoning of sour agent is as follows
(1) Consider the nature and flavor of the product
Malic acid generally used in combination with citric acid, citric acid: malic acid =4:1; Citric acid: tartaric acid =5:1;
It is often used in cold drinks.
Malic acid has obvious taste effect, its sour taste is soft, refreshing, irritating slow, stay for a long time, and citric acid used together, can simulate the sour characteristics of natural fruits, so that the taste is natural, coordinated and full.
Phosphoric acid and tartaric acid have a weak astringent taste, which makes them produce a “natural sour taste” in milk drinks, cola drinks and grape and pineapple products.
The sour taste of tartaric acid has a slightly astringent astringent taste, and the after-taste is long. Its rarely used alone in cold drinks, and often used together with citric acid to increase the after-taste, which can produce a true fruity taste.
Acetic acid and butyric acid have strong irritating taste, and they have the function of strengthening appetite in pickles, synthetic vinegar, cheese and other products.
Lactic acid has a soft sour taste and an aftertaste. When used with acetic acid, it can provide a soft flavor and improve the anti-corrosion effect of the product.
Sour agents with soft sour taste, long duration, good aftertaste and other characteristics the first choice of instant noodle food industry, among which citric acid, malic acid, lactic acid, glacial acetic acid commonly used, others are less used.
(2) Consider what PH value the product reaches
Such as the production of jelly, the PH value is generally 3.6-3.8, generally citric acid and malic acid, the ratio is 3:2, and the buffer salt is sodium citrate.
The acid to salt ratio is 2:1.
(3) Consider the cost of the product
In terms of malic acid, lactic acid and citric acid, citric acid the cheapest price, followed by lactic acid, the most expensive malic acid, generally do a product not the use of a single acid, its best to use two or three acids in combination, generally the most added amount of citric acid, the remaining two acids added appropriately to buffer the single irritation of citric acid.
