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It is a weak organic acid naturally found in citrus fruits, providing the acidic taste and makes citrus fruits taste sour. Also, it plays an important part in the metabolism of most living things as an intermediate in the tricarboxylic acid cycle or Krebs cycle.

Two types in market
There are two forms of citric acid sold in the market, anhydrous and monohydrate. Monohydrate can turn to anhydrous in the condition of heated above 37 °C.

Natural sources
Citrus fruits have a high level of citric acid. Fruit containing citric acid includes:

Lemon
Lime
Pineapple
Oranges
Tomatoes
Strawberries
Peaches
Apples
Grapefruits
Blueberries
Bananas
Concentration
Lemon juice and lime juice are rich in citric acid. The concentration is around 41 mg/kg in ready-to-consume lemon juice and around 31 mg/kg in concentrates. The numbers are 39 mg/kg and 30 mg/kg in lime juice. In commercial lemon juice-based drinks, such as lemonade, the content ranges from 0.62 to 0.96 mg/kg. (1)

How is it made?
Citric acid is commercially produced by microbial fermentation of a glucose or sucrose carbohydrate substrate derived from corn.

Generally made from feeding substrate to black mold. Aspergillus niger is the major organism used in the microbial production of citric acid.

There are three manufacturing processes approved by the FDA as follows (2):

From plant sources, e.g. lemon or pineapple juice.
By mycological fermentation using Candida spp.
From Aspergillus niger fermentation liquor.
A study published in Toxicology Reports in 2018 said that approximately 99% of the world’s output of citric acid is using the fungus Aspergillus niger since 1919. So we can conclude that the third process method above is the most used one. (3)

Specification
Other Names
2-hydroxy-1,2,3-propanetricarboxylic acid
β-Hydroxytricarballylic acid
CAS Number
77-92-9 (anhydrous)
5949-29-1 (monohydrate)
Chemical formula
C6H8O7 (anhydrous)
C6H8O7·H2O (monohydrate)
Molecular Weight
192.13 (anhydrous)
210.14 (monohydrate)
Melting Point 156 °C
Boiling point 310 °C
Structure
citric acid chemical structure

Properties
PKa
PH
Solubility
Appearance
A white crystalline powder or granular with a strongly acidic taste.

Pka
PKa is used to describe the acid dissociation. Citric acid is a weak organic acid containing three carboxylic acid functional groups and as a result it has three PKa values, PKa1 = 3.14, PKa2 = 4.77 and PKa3 = 6.39.

PH
PH measures the concentration of H+ ions or H3O+ ions of the citric acid solution. The PH value depends on the citric acid concentration and its dissociation. It is indicated that the PH value of citric acid is 2.62 in the concentration of 10 mM (0.01mol/L) (4)
http://www.chinafooding.com/1122/What_is_citric_acid?

potassium alginate is a white to yellowish fibrous or granular powder, almost odourless, tasteless. Soluble in water, aqueous solution is neutral. Insoluble in alcohol and aqueous solution which alcohol content is higher than 30%, insoluble in chloroform and acid which PH under 3.
http://www.chinafooding.com/Potassium_Alginate

Magnesium stearate is a kind of tiny, light and white powder with greasy touch sense, insoluble in water, ethanol neither ethoxyethane, but soluble in hot water, hot ethanol, decomposes into stearic acid and magnesium salts when contacting with acid.
It consisting mainly of magnesium stearate and palmitate, is an example of a palm fatty acid product that is used to confer the propertiesof lubricity or fluidity on capsules and tablets of foods with health claims. In particular, magnesium stearate shows a highly favorable lubricity at a low dose when compared with conventional products such as sucrose fatty acid esters.
http://www.chinafooding.com/Magnesium_Stearate

Since stearic acid is a weak organic acid, it cannot directly react with magnesium sulfate to produce magnesium stearate.

In the commercial manufacturing process of magnesium stearate, stearic acid should first be saponified with sodium hydroxide solution to obtain sodium stearate, and then react with the solution of magnesium sulfate or magnesium chloride to synthesize magnesium stearate.

The following are the brief three above mentioned processes:

C17H35COOH + NaOH → C17H35COONa + H2O
2C17H35COONa + MgSO4 → (C17H35COO)2 Mg + Na2SO4
2C17H35COONa + MgCl2 → (C17H35COO)2 Mg + 2NaCl
Specification
Other names Magnesium octadecanoate, Magnesium salts of fatty acids, Magnesium distearate
CAS number 557-04-0
Chemical formula Mg(C18H35O2)2
Molecular weight 591.27
Melting point 88.5 °C (191.3 °F; 361.6 K)
Properties
With both characteristics of metal salt and stearic acid. The lubricity and hydrophobicity are derived from stearic acid.

Stable, but will be decomposed into stearic acid and magnesium salt in case of a strong acid.

A large specific surface area, with strong adsorption and hygroscopicity, a slippery feeling in contact with the skin and is easy to stick to the skin.

Appearance
An off-white to white powder, greasy to the touch.

Solubility
It is an anionic surfactant, unlike with another two metallic stearates (sodium and potassium stearate) but similar with calcium stearate, it is practically insoluble in water with the solubility 0.004 g/100 mL (25 °C).

Partially soluble in ethanol and ether.

Why is it insoluble in water?

The divalent Mg2+ can bind two nonpolar fatty acid molecules while Na+ and K+ as monovalent ions can only combine with one fatty acid.

Two fatty acid molecules protect Mg2+ from interacting with the water molecules and thus make it insoluble in water.

Structure
Magnesium stearate chemical structure
Image Source

It exists as a salt containing two stearate anions and a magnesium cation. Totally there are 36 carbons in length of molecule structure.
http://www.chinafooding.com/Magnesium_Stearate

Guar gum is extracted from the guar in a highly purified natural polysaccharide. Mainly by the galactose and mannose polymer for food from hydroxypropyl guar gum. Are natural galactomannan, a natural thickener.
Guar gum is divided into food grade and industrial grade two, is known to the most effective and best natural water-soluble polymer. Guar gum is a galactomannan.It is typically produced as a free-flowing, pale, off-white colored, coarse to fine ground powder. Guar gum is an extract of the guar bean. Guar gum is a polysaccharide composed of the sugars galactose and mannose.

Guar gum is extracted from guar bean,has the largest molecular weight. Guar gum can be applied in food. ,pharmacy, paper-making, textile and artesian well industry as thickener, stabilizer, emulsion, ES, SC and compatibilizer.

Guar gum in the food industry in the application:
1. Guar gum in the cold such as ice cream, ice cream, frost, borneol play a role in good stabilizer to prevent ice crystals produced, plays a thickening, emulsifying effect.
2. Guar gum in the face of products such as noodles, noodles, instant noodles, vermicelli play to prevent the adhesive, water retention, increased muscle strength and maintain good quality of the role, and to extend the shelf life.
3. Guar gum in the beverage, such as peanut milk, almond milk, walnut milk, orange capsules, juice, tea, beverages and rice pudding in a variety of solid play thickening and stabilizing agent holding the role of water and improve taste and effect.
4. Guar gum in dairy products if milk, yogurt stabilizer role to play, and play a thickening, emulsifying, E412 to improve the taste of the role.
5. Guar gum in soy products such as tofu, soy milk play a stabilizing role.
6. Guar gum in meat products such as ham, luncheon meat, all kinds of meatball play bond, refreshing and increase the volume effect.

Guar gum is widely used as food additive and ingredients.
http://www.chinafooding.com/Guar_Gum