Syneresis (chemistry)
Encyclopedia
Syneresis in chemistry, is the extraction or expulsion of a liquid
from a gel
, as when lymph
drains from a contracting clot of blood
. Another example of syneresis is the collection of whey
on the surface of yogurt. Syneresis can also be observed when the amount of diluent in a swollen polymer exceeds the solubility limit as the temperature changes. A household example of this is the counter intuitive expulsion of water from dry gelatin when the temperature increases. Syneresis has also been proposed as the mechanism of formation of the amorphous silicate
composing the frustule
of diatom
s
In the processing of dairy milk
, for example during cheese making, syneresis is the formation of the curd
due to the sudden removal of the hydrophilic macropeptides, which causes an imbalance in intermolecular forces. Bonds between hydrophobic sites start to develop and are enforced by calcium
bonds which form as the water molecules in the micelles start to leave the structure. This process is usually referred to as the phase of coagulation and syneresis. The splitting of the bond between residues 105 and 106 in the κ-casein
molecule is often called the primary phase of the rennet
action, while the phase of coagulation and syneresis is referred to as the secondary phase.
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...
from a gel
Gel
A gel is a solid, jelly-like material that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state...
, as when lymph
Lymph
Lymph is considered a part of the interstitial fluid, the fluid which lies in the interstices of all body tissues. Interstitial fluid becomes lymph when it enters a lymph capillary...
drains from a contracting clot of blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
. Another example of syneresis is the collection of whey
Whey
Whey or Milk Serum is the liquid remaining after milk has been curdled and strained. It is a by-product of the manufacture of cheese or casein and has several commercial uses. Sweet whey is manufactured during the making of rennet types of hard cheese like cheddar or Swiss cheese...
on the surface of yogurt. Syneresis can also be observed when the amount of diluent in a swollen polymer exceeds the solubility limit as the temperature changes. A household example of this is the counter intuitive expulsion of water from dry gelatin when the temperature increases. Syneresis has also been proposed as the mechanism of formation of the amorphous silicate
Silicon dioxide
The chemical compound silicon dioxide, also known as silica , is an oxide of silicon with the chemical formula '. It has been known for its hardness since antiquity...
composing the frustule
Frustule
A frustule is the hard and porous cell wall or external layer of diatoms. The frustule is composed almost purely of silica, made from silicic acid, and is coated with a layer of organic substance, which was referred to in the early literature on diatoms as pectin, a fiber most commonly found in...
of diatom
Diatom
Diatoms are a major group of algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons , fans , zigzags , or stellate colonies . Diatoms are producers within the food chain...
s
In the processing of dairy milk
Milk
Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...
, for example during cheese making, syneresis is the formation of the curd
Curd
Curds are a dairy product obtained by curdling milk with rennet or an edible acidic substance such as lemon juice or vinegar, and then draining off the liquid portion. The increased acidity causes the milk proteins to tangle into solid masses, or curds. The remaining liquid, which contains only...
due to the sudden removal of the hydrophilic macropeptides, which causes an imbalance in intermolecular forces. Bonds between hydrophobic sites start to develop and are enforced by calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
bonds which form as the water molecules in the micelles start to leave the structure. This process is usually referred to as the phase of coagulation and syneresis. The splitting of the bond between residues 105 and 106 in the κ-casein
Casein
Casein is the name for a family of related phosphoprotein proteins . These proteins are commonly found in mammalian milk, making up 80% of the proteins in cow milk and between 60% and 65% of the proteins in human milk....
molecule is often called the primary phase of the rennet
Rennet
Rennet is a complex of enzymes produced in any mammalian stomach to digest the mother's milk, and is often used in the production of cheese. Rennet contains many enzymes, including a proteolytic enzyme that coagulates the milk, causing it to separate into solids and liquid...
action, while the phase of coagulation and syneresis is referred to as the secondary phase.