An indispensable acidity regulator in food processing

Acidity regulator, also known as pH adjuster, "Food Additive Use Standard" (GB 2760-2014) stipulates: acidity regulator is used to maintain or change the pH of food substances
.
At present, the acidity regulators allowed to be used in China are: citric acid, lactic acid, tartaric acid, malic acid, acetic acid, fumaric acid and dozens of others
.

Various acidulants have different acidity, acuity and speed
of taste.
Acidity and the acidity caused in the mouth are related
to the type of acid, pH, titratable acidity, buffer solutions and the presence of other substances, especially sugars.

At the same pH value, organic acids are stronger than inorganic acids, and the order of acidity from strong to weak is: acetic acid> formic acid> lactic acid> oxalic acid> hydrochloric acid
.
If the acidity intensity of citric acid is set at 100, the comparative strength of tartaric acid is 120-130, phosphoric acid is 200-230, fumarate is 263, and L-ascorbic acid is 50
.
In addition, the length of sour taste is different, the sour taste with slow dissociation rate lasts for a long time, and the taste of sour substances with fast dissociation disappears
quickly.

The factors that affect the sour taste can be roughly divided into three aspects
.
Temperature: The general temperature has little effect on the sour taste, and the sour taste is the least affected by temperature compared with the sweet, salty and bitter taste; Anions of acidity regulators: At the same concentration, the various acidic and sour tastes of different anions are different, which is caused by the effect of the anions dissociated by
the acidulant on the sense of taste.
Therefore, the sour taste of one acid cannot completely replace the sour taste
of another acid with the same weight or concentration.
In addition, the absence of hydroxyl, amino, carboxyl groups on the anion and their number and position also have an effect on the flavor of the sour agent; Influence of other tastes: sour taste and other tastes can affect each other, sweetness and sour taste are easy to cancel each other, have sanitize effect, so generally in food processing to control the appropriate ratio of
sugar acid.
The sourness, bitterness and saltiness are difficult to cancel each other out, and there is generally no sanitize phenomenon
.
Acidity regulators mixed with astringent substances or astringent substances such as tannins can enhance
the acidity.

There are many classification methods of acidity regulators, and according to different effects, acidity regulators can be divided into acidifiers, alkalizing agents and salts (buffers)
with buffering effect.
In the application, organic acids and salts with buffering effect are the mainstay
.

Acidulants are also called acidulants, and food additives that give food sour taste as the main purpose are called acidulants
.
The most used acidity regulator is the acidity agent, the acidity agent can be divided into inorganic acids and organic acids according to its chemical properties, because many organic acids are normal components of food, or participate in the normal metabolism of the human body, so the safety is high and the use range is wide; Alkalizing agent, also known as alkaline agent, includes 10 kinds of calcium hydroxide, potassium hydroxide, sodium hydroxide, trisodium bicarbonate, sodium carbonate, potassium bicarbonate, etc.
; Buffer: including sodium
citrate, potassium citrate, monosodium citrate, sodium lactate.
In regulating sourness, citrate is superior to phosphate, and its sour taste appears more peaceful
.

By adjusting the acidity and alkalinity of the food system, the optimal form and toughness of the food can be maintained, and the pH value of the system can be reduced to achieve the purpose
of bacteriostasis.
In gels, pectins, jellies, gummies, jams and other products, in order to obtain the optimal form and toughness of the product, the pH value must be adjusted correctly, especially the gel of pectin and the
coagulation of cheese.
The acidulant reduces the pH value of the system, most bacteria tolerate pH 6.
5-7.
5, a few tolerate pH 3-4 range (such as yeast, mold), therefore, the acidulant to adjust the acidity to play a preservative effect, thereby reducing the adverse effects
of high temperature on food structure and flavor.
In addition, lowering the pH can reduce the reproduction
of harmful microorganisms.
The reproduction and survival of microorganisms requires a certain pH value, and most bacteria survive with a pH value of 6.
5-7.
5
.
pH below 4.
5 can inhibit the reproduction of most bacteria, so adjusting the acidity with an acidity regulator can play a role
in preservative.

At the same time, the acidulant can also be used as a flavor aid to form a characteristic flavor
.
The addition of malic acid in food processing can assist the aroma of fruits and jams; tartaric acid assists grape aromas; Phosphoric acid can complement the Coca-Cola flavor; The sour taste of citric acid can mask or reduce certain odors
.
In addition, acidulants can balance the flavor and modify the sweetness of sucrose or sweeteners
.
Candy, jam, juice, beverages, etc.
without acidity regulator taste dull, sweet is also very monotonous, adding an appropriate amount of acidity regulator to adjust the sugar-acid ratio, can significantly improve the flavor of food, make the product more palatable
.

The acidulant can chelate metal ions, avoid oxidation, discoloration and decay, and can be used with other additives to increase efficiency
.
Such as iron ions, copper ions can oxidize oil, vegetable browning, pigment fading, adding metal chelating agent is a feasible way, acidulant has chelating effect, and metal ions are combined to make it inactive
.

Acidulants also have a buffering effect
.
Food processing and preservation require a stable pH value, so the pH value fluctuation range is very narrow
.
Simple acid-base adjustment pH value is easy to lose balance, with organic acids and their salts to form a buffer system, can inhibit excessive pH fluctuations caused by changes in acid and alkali content during raw material blending and processing, such as in candy production can be used for the conversion of sucrose, inhibition of browning
.

In addition, acidity regulators can also be used as leavening agents, such as carbon dioxide with carbonates; It has reducibility, such as color protection agent in fruits and vegetables, and color protection auxiliaries in meat; It has a passivation effect, such as acidulant has a passivation effect on the esterase
.

(Yu Jiamin)

China Food News (October 24, 2022, Edition 06)

(Editor: Yang Xiaojing)