The shortening is derived from the English word “shorten”, which means that the processing of biscuits and the like with such a grease makes the product very crisp, and thus the fat having this property is called “shortening”. It refers to a refined animal or vegetable fat, a hydrogenated oil or a mixture of the above-mentioned oils, a solid oil obtained by quenching and kneading, or a solid or fluid dynamic fat product which is not quenched and kneaded. The shortening has the processing properties such as plasticity and emulsifying properties, and is generally not suitable for direct consumption, but is used for processing cakes, breads or fried foods, so it must have good processing properties. The properties of the shortening are different and the production process is also different.
There are many varieties of shortening in foreign markets. According to the above classification, serialize again. For example, the degree of hydrogenation of the oil, the size of the plasticity, the aeration rate, the consistency or viscosity, the oil content of the powder, and the like. However, there are no domestically produced varieties in the domestic market. The food industry has not proposed various or special requirements for this, so it is only in its infancy in this respect. Powdered shortening has been produced in China and is micro-capsule type with oil content of 20-80%.
Since shortening is a raw material fat for food processing, its functional properties are particularly important, including plasticity, tyro sine, shortening, emulsifying, and water absorption.
Plasticity means that under the action of an external force, it can change its shape and even flow like a liquid. In theory, if the solid fat is plastic, it must contain a certain amount of solid fat and liquid oil. Shortening products basically have this fat composition. Due to the plasticity of the shortening, it can form a fine stripe film when mixed with the dough during food processing. Under the same conditions, the liquid oil can only be dispersed into a granular or spherical shape. When the dough is processed with a good shortening, the dough has good ductility and can absorb or maintain a considerable amount of air, which is very advantageous for the production of baked goods.
When the shortening is foamed by high-speed agitation in the air, fine bubbles in the air are sucked in by the shortening oil, and this gas-containing property of the fat is called styling property. The size of the casein is expressed by the casein value, which is 100 times the number of milliliters of air contained in one gram of the sample.
The styling property is an important property of food processing. The shortening is added to the dough, and after stirring, the volume of the dough is increased, and the prepared food is loose and soft.
The shortening means that the food has crispy and brittle nature, and is especially important for baked goods such as biscuits, wafers and meringues. When the food is prepared by shortening, the oil and fat cover the periphery of the flour due to its film forming property, and the mutual combination of the flours is blocked to prevent gluten and starch from sticking. In addition, the shortening acts as a lubricating agent in the layered baked food tissue, making the food tissue weak and brittle.
Shortening is not the name used internationally. Some countries in Europe call ghee a CompouNd Cooking Fat. Shortening initially refers to a class of malleable solid fats used to crisp or soften baked goods. Since the newly developed fluid state, powdered shortening and margarine with less than 20% water phase have the functional properties imparted by plastic fat, today’s shortenings contain a broad product range.
Therefore, it is difficult to give a precise definition of it. However, in general, shortening refers to a mixture of refined animal and vegetable oils, hydrogenated oils or a mixture of the above-mentioned fats and oils, which are solidified or fluidized by means of rapid kneading or kneading without kneading. Grease products. All fat products that have a glossy appearance and surface, as well as emulsified, layered and lubricated applications, are shortenings. The main difference between shortening and margarine is that the shortening is mostly free of water and cannot be eaten directly. It is often used in baked goods, cheese making or food frying.
The shortening is a plastic fat, and the composition of the triglyceride contains a considerable amount of saturated acid ester. At room temperature, these saturated acid esters are contained in the fine solid crystal to contain the liquid fat to form a plastic state which is resistant to the fine applied stress. Butter and lard are natural plastic fats, which have long been valued and widely used because they can block protein and starch from binding to starch in the processing of baked goods. But the lack of resources can not meet the increasing consumer demand, which inspires scientists to constantly seek to develop alternative oil products.
At the end of the 19th century, with the advent of the first generation of margarine, people first replaced the fat with bovine soft fat. In 1860-1865, Americans blended refined cotton oil with beef stearin to make the first generation of plastic fat, 1910 The United States introduced Europe to introduce hydrogenation technology to process unsaturated vegetable oil and marine animal oil into hard fat of suitable consistency. It is used in the production of bread, cakes and other foods. Its antioxidant and functional properties are better than lard; Going into a new era. Shortening oils are classified into common type, stable type and high emulsified type according to their use in food processing. Its functional properties are mainly obtained by hydrogenation or transesterification of grease modification technology and processing. Nowadays, the technical requirements of the food industry for the shortening of the shortening function are getting higher and higher. With the progress of hydrogenation and transesterification technology, scientists are making unremitting efforts on the research of shortening.