The first extruder was designed to make sausages in the 1870s.[4] Dry pasta and breakfast cereals have been produced by extrusion since the 1930s,[2] and the method has been applied to pet food production since the 1950s (the first extruded dog food was Purina Dog Chow in 1957, and the first extruded cat food was Purina Friskies in 1962).[4] Some kitchen appliances, such as meat grinders and some types of pasta makers, use extrusion. Hand-squeezed pastry bags work by extrusion.

Extrusion allows the mass production of food through a continuous and efficient system that guarantees the uniformity of the final product. This is achieved by controlling various aspects of the extrusion process. It has also enabled the production of new processed food products and "revolutionized many conventional snack manufacturing processes."[5]​ The extrusion process results in "chemical reactions that occur within the extruder barrel and in the die."[6]​ Extrusion has the following effects:[7]​[8]​[9]​.

The material an extrusion die is made of can affect the final product. The rough bronze dies of pasta extruders produce a rougher surface than smooth stainless steel dies, which is considered to make thinner pasta sauces stick better;[11]​ Pasta made this way is labeled "bronze pasta", indicating a premium product.[12]​.

The effects of extrusion cooking on nutritional quality are ambiguous,[13]​ as extrusion can change the carbohydrates, dietary fiber, protein and amino acid profile, vitamins, and mineral content of the extrudate both beneficially and detrimentally.[13]​.

High-temperature, short-duration extrusion "minimizes losses of vitamins and amino acids."[1]​ Extrusion allows mass production of some foods and "will denature anti-nutritional factors,"[1]​ such as the destruction of toxins or the death of microorganisms. It can also improve the quality and digestibility of proteins[1]​ and affects the shape, texture, color and flavor of the product.[1]​.

It can also cause the fragmentation of proteins, starches and non-starch polysaccharides creating reactive molecules that can form new bonds that are not found naturally,[6]​ this includes Maillard reactions that reduce the nutritional value of proteins.[13]​ Vitamins with thermolability can be destroyed. [13] Little is known about the stability or bioavailability of the phytochemicals involved in extrusion.[6] It has been found that nutritional quality improves under moderate conditions (short duration, high humidity, low temperature), while with high temperature (at least 200 °C), low humidity (less than 15%) or inadequate components in the mixture, there is a negative effect on the nutritional quality of the extrudate.[13]​.

A 2012 research paper indicates that the use of non-traditional cereal flours, such as amaranth, buckwheat or millet, can be used to reduce the glycemic index of breakfast cereals produced by extrusion. of 2008 states that replacing 5% to 15% of wheat flour and white flour with dietary fiber in the extruded breakfast cereal mixture significantly reduces the rate and degree of carbohydrate hydrolysis of the extruded products,[10]​ which increases the level of slowly digestible carbohydrates and reduces the level of rapidly digestible carbohydrates.[10]​.

Extrusion has allowed the production of new processed food products and revolutionized many conventional snack manufacturing processes.[5]​.

Different types of food products manufactured by extrusion typically have a high starch content.[1]​ Directly expanded types include breakfast cereals and corn curls, and are made under high-temperature, low-humidity conditions under high shear. Unexpanded products include pasta, which is produced with intermediate humidity (around 40%) and low temperature. Textured products include meat analogues, which are made using vegetable proteins ("textured vegetable protein") and a long die to "impart a meat-like fibrous structure to the extrudate",[4]​ and fish paste").[15]​ Confectionery products made by extrusion include chewing gum, licorice and caramel.[15]​.

Some processed cheeses and cheese analogues are also made by extrusion. Processed cheeses extruded with low humidity and temperature "could have a more suitable manufacturing" than those with high humidity or temperature. Cheeses with lower moisture are firmer and chewier, and cheddar cheese extruded with low moisture and an extrusion temperature of 80 °C was preferred over other cheddar cheeses produced under different extrusion conditions, according to one study.[16]​ An average extrudate residence time of approximately 100 seconds can produce "processed cheeses or cheese analogues of variable texture (spreadable or sliceable)."[17]​.

Other food products that are often produced by extrusion include some breads (croutons, breadsticks, and flatbreads), various ready-to-eat snacks, pre-made cookie dough, some baby foods, some beverages, and dry and semi-moist pet foods. Specific examples include cheese bites, macaroni, Fig Newtons, "Dragee (sweet)" gummies, sevai, and some potato chips. Extrusion is also used to modify starch and granulate animal feed.[18]​.

The first extruder was designed to make sausages in the 1870s.[4] Dry pasta and breakfast cereals have been produced by extrusion since the 1930s,[2] and the method has been applied to pet food production since the 1950s (the first extruded dog food was Purina Dog Chow in 1957, and the first extruded cat food was Purina Friskies in 1962).[4] Some kitchen appliances, such as meat grinders and some types of pasta makers, use extrusion. Hand-squeezed pastry bags work by extrusion.

Extrusion allows the mass production of food through a continuous and efficient system that guarantees the uniformity of the final product. This is achieved by controlling various aspects of the extrusion process. It has also enabled the production of new processed food products and "revolutionized many conventional snack manufacturing processes."[5]​ The extrusion process results in "chemical reactions that occur within the extruder barrel and in the die."[6]​ Extrusion has the following effects:[7]​[8]​[9]​.

The material an extrusion die is made of can affect the final product. The rough bronze dies of pasta extruders produce a rougher surface than smooth stainless steel dies, which is considered to make thinner pasta sauces stick better;[11]​ Pasta made this way is labeled "bronze pasta", indicating a premium product.[12]​.

The effects of extrusion cooking on nutritional quality are ambiguous,[13]​ as extrusion can change the carbohydrates, dietary fiber, protein and amino acid profile, vitamins, and mineral content of the extrudate both beneficially and detrimentally.[13]​.

High-temperature, short-duration extrusion "minimizes losses of vitamins and amino acids."[1]​ Extrusion allows mass production of some foods and "will denature anti-nutritional factors,"[1]​ such as the destruction of toxins or the death of microorganisms. It can also improve the quality and digestibility of proteins[1]​ and affects the shape, texture, color and flavor of the product.[1]​.

It can also cause the fragmentation of proteins, starches and non-starch polysaccharides creating reactive molecules that can form new bonds that are not found naturally,[6]​ this includes Maillard reactions that reduce the nutritional value of proteins.[13]​ Vitamins with thermolability can be destroyed. [13] Little is known about the stability or bioavailability of the phytochemicals involved in extrusion.[6] It has been found that nutritional quality improves under moderate conditions (short duration, high humidity, low temperature), while with high temperature (at least 200 °C), low humidity (less than 15%) or inadequate components in the mixture, there is a negative effect on the nutritional quality of the extrudate.[13]​.

A 2012 research paper indicates that the use of non-traditional cereal flours, such as amaranth, buckwheat or millet, can be used to reduce the glycemic index of breakfast cereals produced by extrusion. of 2008 states that replacing 5% to 15% of wheat flour and white flour with dietary fiber in the extruded breakfast cereal mixture significantly reduces the rate and degree of carbohydrate hydrolysis of the extruded products,[10]​ which increases the level of slowly digestible carbohydrates and reduces the level of rapidly digestible carbohydrates.[10]​.

Extrusion has allowed the production of new processed food products and revolutionized many conventional snack manufacturing processes.[5]​.

Different types of food products manufactured by extrusion typically have a high starch content.[1]​ Directly expanded types include breakfast cereals and corn curls, and are made under high-temperature, low-humidity conditions under high shear. Unexpanded products include pasta, which is produced with intermediate humidity (around 40%) and low temperature. Textured products include meat analogues, which are made using vegetable proteins ("textured vegetable protein") and a long die to "impart a meat-like fibrous structure to the extrudate",[4]​ and fish paste").[15]​ Confectionery products made by extrusion include chewing gum, licorice and caramel.[15]​.

Some processed cheeses and cheese analogues are also made by extrusion. Processed cheeses extruded with low humidity and temperature "could have a more suitable manufacturing" than those with high humidity or temperature. Cheeses with lower moisture are firmer and chewier, and cheddar cheese extruded with low moisture and an extrusion temperature of 80 °C was preferred over other cheddar cheeses produced under different extrusion conditions, according to one study.[16]​ An average extrudate residence time of approximately 100 seconds can produce "processed cheeses or cheese analogues of variable texture (spreadable or sliceable)."[17]​.

Other food products that are often produced by extrusion include some breads (croutons, breadsticks, and flatbreads), various ready-to-eat snacks, pre-made cookie dough, some baby foods, some beverages, and dry and semi-moist pet foods. Specific examples include cheese bites, macaroni, Fig Newtons, "Dragee (sweet)" gummies, sevai, and some potato chips. Extrusion is also used to modify starch and granulate animal feed.[18]​.