What are the properties of calcium hydroxide in food applications?

calcium hydroxide

Food additives are chemically synthesized or natural substances added to food to improve food quality, color, aroma and taste, as well as for preservation and processing requirements.

Nutritional fortifiers, food flavors, basic substances in gum-based candies, and processing aids for food industry are also included; processing aids for food industry are various substances that ensure the smooth progress of food processing, and have nothing to do with the food itself. Such as filter aid, clarification, adsorption, lubrication, mold release, decolorization, peeling, solvent extraction, nutrients for fermentation, etc.

Therefore, the concept of food additives can be divided into broad and narrow senses, and food additives in a broad sense include processing aids. Food additives in a narrow sense are different from processing aids, which refer to additives with specific connotations such as colorants, preservatives, and acidity regulators.

Calcium hydroxide, also known as slaked lime or slaked lime, is generally in powder form.

Because the solubility of calcium hydroxide is much smaller than that of sodium hydroxide and potassium hydroxide, the corrosiveness and alkalinity of its solution are also relatively small, so it can be used as an acidity regulator in food for buffering, neutralization and curing. and so on. Food grade calcium hydroxide has relatively high activity, relatively loose structure, high purity, good whiteness, low impurity content, and does not contain harmful elements such as Pb and As.

01 Can be applied to some dairy products

Calcium hydroxide is a kind of food additive available in my country, which can be used in modulated milk, milk powder and infant formula food.

Proteins have a net charge due to the presence of ionic side chains, and each protein has a pH value that can make it uncharged. We call this pH value the isoelectric point. At the isoelectric point, protein molecules exist in the form of zwitterions, and the net charge of the molecules is zero. At this time, the protein molecules do not repel each other with the same charge in the solution, and the interaction between the molecules is weakened. Precipitation occurs due to collision and agglomeration, so when the protein is at the isoelectric point, its solubility is the smallest, and it is most likely to form a precipitate. Different proteins have different isoelectric points due to differences in molecular structure. For example, α-casein is 4.5, β-casein is 6, and soybean protein is 4.5.

The purpose of using calcium hydroxide in dairy products is to make it deviate from the isoelectric point and find an optimal dissolution condition. At this time, the solubility and dispersibility of the protein are better.

02 The application in food needs to be expanded

Due to the poor solubility of calcium hydroxide, the stability and safety of its aqueous solution have unique advantages compared with other strong alkalis such as potassium hydroxide, especially in flour products.

In 2016, Xi’an City, Shaanxi Province issued the “Technical Specifications for the Production of Traditional Snacks in Xi’an”, in which it is clear that calcium hydroxide can be used in Lantian buckwheat noodles, which is also the only official guidance document for the use of calcium hydroxide in flour products. Calcium hydroxide has the effect of astringing gluten in noodle products, which is equivalent to the effect of edible alkali, and has a very significant performance in noodles, which can improve the palatability of noodles, reduce the rate of noodle breakage, and prevent the soup from being muddy. From this point of view, calcium hydroxide has good application advantages in flour products, especially in improving the quality of coarse grain flour products, which is worthy of further study.

03 Processing aids are more widely used

Another processing advantage of calcium hydroxide is that it can be used as a processing aid in various foods, and its removal method is relatively simple. It can be filtered out by the precipitation of carbon dioxide. For example, calcium hydroxide is commonly used in the sugar industry. Acid neutralization.

The most representative food of calcium hydroxide as a processing aid is konjac. The folk production and consumption of konjac food in our country has a history of more than 2,000 years. Konjac must be solidified under alkaline conditions. It has advantages in terms of sex, so calcium hydroxide has become an auxiliary substance commonly used in the production of konjac.

Is calcium hydroxide an acidity regulator or a processing aid in konjac food? It can be considered from three aspects: the characteristics of calcium hydroxide, konjac food technology and industry viewpoints.

  • The chemical formula of calcium hydroxide is Ca(OH)2, commonly known as slaked lime or slaked lime, which is a white powdery solid. The main component of food-grade calcium hydroxide is lime through processing and refining to remove harmful substances such as heavy metals. Because of its strong alkalinity and low solubility, it is widely used in the konjac food production industry to play the role of pH adjustment and coagulation;
  • Konjac gel food is generally formed by adding water and puffing konjac powder, adding calcium hydroxide for refining, heating and solidifying to shape, and there is no calcium hydroxide component discharge process;
  • The Konjac Association of the Chinese Horticultural Society, in the description of the preparation of the “Konjac Gel Food” standard, clearly intends to refer to the regulations and according to the needs of the konjac gel food processing technology, to include calcium hydroxide in the “Konjac Gel Food” standard. As an acidity regulator, the maximum usage is stipulated as “use in moderation according to production needs”. Calcium hydroxide should be recognized as an acidity regulator rather than a processing aid in konjac food processing.

The konjac gel food made with calcium hydroxide is superior to other alkalis in terms of gel, taste, color and economy, and calcium ions can also be absorbed by the human body. On the other hand, the prepared konjac gel food must be immersed in liquid for preservation, so calcium hydroxide also acts as an acidity regulator. In developed countries such as the United States and Japan, calcium hydroxide is recognized as an alkali (acidity regulator) used in the konjac food industry, and there are no restrictions on the scope and amount of calcium hydroxide used as an additive.

Calcium hydroxide is a kind of processing aid that can be used in various food processing processes and the residual amount does not need to be limited, which makes its application range relatively wide, but the processing aid must have the necessity of technology, which is another The disguised form limits its application. For example, the use of calcium hydroxide in flour products is not necessary for the process and cannot be used as a processing aid. From this point of view, calcium hydroxide is a potential flour product improver, but to obtain a formal “identity”, more research and application support are needed.


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