acidity

The most important property of carboxylic acids, and the one that is responsible for naming them such, is their acidity. An acid is any compound that donates a hydrogen ion, H⁺ (also called a proton), to another compound, termed a base. Carboxylic acids do…

In general, fruits are acidic, with pH ranging from 2.5 to 4.5. The most common acids in fruits are citric acid, malic acid, and tartaric acid.

Acidity increases with increasing oxidation number of the element. For example, of the five oxides of manganese, MnO (in which manganese has an oxidation state of +2) is the least acidic and Mn₂O₇ (which contains Mn⁷⁺) the most acidic. Oxides of the transition metals with…

Although phenols are often considered simply as aromatic alcohols, they do have somewhat different properties. The most obvious difference is the enhanced acidity of phenols. Phenols are not as acidic as carboxylic acids, but they are much more acidic than aliphatic alcohols,…

Foods with substantial acidity, when concentrated to 65 percent or more soluble solids, may be preserved by mild heat treatments. High acid content is not a requirement for preserving foods concentrated to over 70 percent solids.

The premier role of acidity in preservation is to stop bacterial growth. Second, increased acidity can activate chemical reactions such as pectin set, which lowers water activity and reduces the possibility of microbial growth.

…a successful preserve are sugar, acid, and pectin. These three ingredients lower the pH of the preserve and bind available water, thus creating an environment in which the growth of microorganisms is retarded. In some cases the fruit can provide all the pectin and acid that are needed. If the…

In acidic soils some nutrients are far more available and may reach concentrations that are toxic or that inhibit absorption of other nutrients, while other minerals become chemically bound and unavailable to plants. A similar situation exists in alkaline soils, although different minerals are affected. Oats…