Food rheology is the study of the rheological properties of

food Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is in ...

, that is, the consistency and flow of food under tightly specified conditions. The consistency, degree of fluidity, and other mechanical properties are important in understanding how long food can be stored, how stable it will remain, and in determining food texture. The acceptability of food products to the consumer is often determined by food texture, such as how spreadable and creamy a food product is. Food rheology is important in

quality control Quality control (QC) is a process by which entities review the quality of all factors involved in production. ISO 9000 defines quality control as "a part of quality management focused on fulfilling quality requirements". This approach place ...

during food manufacture and processing. Food rheology terms have been noted since ancient times. In ancient

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a List of transcontinental countries, transcontinental country spanning the North Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via a land bridg ...

, bakers judged the consistency of dough by rolling it in their hands.

Overview

There is a large body of literature on food rheology because the study of food rheology entails unique factors beyond an understanding of the basic rheological dynamics of the flow and deformation of matter. Food can be classified according to its rheological state, such as a

solid Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structur ...

gel A gel is a semi-solid 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, although the liquid phase may still di ...

liquid A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. As such, it is one of the four fundamental states of matter (the others being solid, gas, ...

emulsion An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Alth ...

with associated rheological behaviors, and its rheological properties can be measured. These properties will affect the design of

food processing Food processing is the transformation of agricultural products into food, or of one form of food into other forms. Food processing includes many forms of processing foods, from grinding grain to make raw flour to home cooking to complex in ...

plants, as well as

shelf life Shelf life is the length of time that a commodity may be stored without becoming unfit for use, consumption, or sale. In other words, it might refer to whether a commodity should no longer be on a pantry shelf (unfit for use), or no longer on a ...

and other important factors, including sensory properties that appeal to consumers. Because foods are structurally complex, often a mixture of fluid and solids with varying properties within a single mass, the study of food rheology is more complicated than study in fields such as the rheology of

polymers A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...

. However, food rheology is something we experience every day with our perception of food texture (see below) and basic concepts of food rheology well apply to polymers physics, oil flow etc. For this reason, examples of food rheology are didactically useful to explain the dynamics of other materials we are less familiar with. Ketchup is commonly used an example of Bingham fluid and its flow behavior can be compared to that of a polymer melt.

Psychorheology

Psychorheology is the sensory judgement of rheological properties. It is a term used in the

food industry The food industry is a complex, global network of diverse businesses that supplies most of the food consumed by the world's population. The food industry today has become highly diversified, with manufacturing ranging from small, traditional, ...

, to describe how a food "feels" to the mouth. It is not necessarily straightforward to predict how a food will "feel" based purely on the true rheological properties. The most important factor in food rheology is

consumer A consumer is a person or a group who intends to order, or uses purchased goods, products, or services primarily for personal, social, family, household and similar needs, who is not directly related to entrepreneurial or business activities. ...

perception of the product. This perception is affected by how the food looks on the plate as well as how it feels in the mouth, or "

mouthfeel Mouthfeel refers to the physical sensations in the mouth caused by food or drink, making it distinct from taste. It is a fundamental sensory attribute which, along with taste and smell, determines the overall flavor of a food item. Mouthfeel ...

". Mouthfeel is influenced by how food moves or flows once it is in a person's mouth and determines how desirable the food is seen to be.

Notes

References

* * * {{Food science Rheology Food science Food industry

Overview

Psychorheology

See also

Notes

References