While having a significant effect on the flavour of food products, acidulants perform a variety of other beneficial functions.

While having a significant effect on the flavour of food products, acidulants perform a variety of other beneficial functions:

  • Taste: The sharpness in the taste of any food is due to the presence of food acids. All fruits have these acids in some quantity and the result is the typical acidic taste normally associated with fruit.
  • Enhance fruit flavours: Naturally occurring food acids are citric acid, malic acid and tartaric acid. They are also called wholesome acids. They are found in oranges, grapefruits, pineapples, apples, peaches and other seeded fruits. Tartaric acid is found in grapes, pineapples and potatoes. Without the presence of these acids, fruits may taste bland.
  • Antimicrobial effect: Some acids, such as acetic acid and lactic acid, have an anti-microbial effect and are the basis for preservation by fermentation in products such as sauerkraut and pickles.
  • Reduce spoilage: The use of acids to reduce pH retards the growth of many spoilage organisms, especially bacteria, and also increases the effectiveness of food preservatives such as benzoates, sorbates and propionates.
  • Prevents discolouration: Acidification also retards the action of many natural enzymes that are involved in the discolouration of cut fruit and vegetables, and increases the effectiveness of natural and added antioxidants.
  • Synergistic effect with Antioxidants: Some acids, such as citric acid, exert a synergistic effect with antioxidants through their ability to chelate metal ions that catalyse oxidation and bring about rancidity and deterioration.
  • pH Control: Acids are also used for pH control, particularly when the pH needs to be controlled to obtain the best gel strength in products such as pectin jellies and jams.
  • Buffering: Some products, particularly diet beverages, require some buffering to improve flavour. The addition of a small amount of ADM Sodium Citrate can often enhance flavour

The main acidulants offered by HWL are:

  • Adipic acid
  • Citric acid
  • Glucono delta lactone (GDL)
  • Lactic acid
  • Tartaric acid

Adipic acid is characterised by being a stable powder and is slightly soluble in water. It has a pH of 2.86 at 0.6% and is used in powdered drinks, beverages, gelatine desserts and vegetables. It can also be used as a leavening acidulant in baking powder and as a buffering agent to maintain acidity within a pH range of 2.5 to 3.0.

Citric acid is the dominant acid in orange juice, lemons and limes. It exists in either anhydrous or monohydrate forms. Typically it is sold as a powder or as a fine granular crystal.

Anhydrous citric acid is very soluble in water and has a pH of 2.3 for a 1% solution. It is relatively hygroscopic and has a strong acid tart flavour. It is used as an acidulant in fruit drinks and carbonated beverages at 0.25 to 0.4%. It is often used in combination with antioxidants in the processing of fresh frozen fruits to prevent discolouration.

Glucono-delta-lactone

An acidulant often abbreviated to GDL. (Not to be confused with Glucoronolactone, D-glucorono-3,6-lactone, or DGL).

It hydrolyses to form gluconic acid in water and thereby creates the desired pH. The rate of acid formation is affected by temperature, concentration and the pH of the solution. It has low acid release at room temperature and accelerates the conversion to gluconic acid as the temperature increases. It is readily soluble in water and is used a chemical leavening agent in tofu and also as a pH modifier in smallgoods such as sausages and frankfurters. It is thought to be one of the best acids to reduce pH without giving an excessive acidic flavour profile to the food product.

Glucono Delta-Lactone applications

Lactic acid is an acidulant that is a natural organic acid present in milk, meat and wine, but is normally associated with acidified dairy products such as yoghurt. It is a syrupy liquid available as 80 or 88% liquid form, as lactic acid anhydrous is very hygroscopic. It is heat-stable, non-volatile and has a smooth milk acid taste. It is often used to provide buttery notes to beverages and dairy products and reduce the pH below pH 4 without adversely affecting the flavour of the food product.

Tartaric acid is an acidulant derived from grapes and is very soluble in water. It has a slightly tarter taste profile than citric acid and is often used in grape and lime flavoured beverages. Tartaric acid is available in a medium granular form and complies with the FCC standards.

Properties of Common Food Acidulants