Invert sugar is a colorless, flavorless syrup which sweetens, improves quality and extends shelf life of baked goods and confections. It is derived from sucrose (a.k.a. table sugar), a disaccharide made of two monosaccharide sugar units.
When a disaccharide undergoes a process called inversion, it splits into its component monosaccharides. In the case of sucrose, these are glucose and fructose. Fructose is much sweeter than sucrose or glucose, making invert sugar is sweeter than sucrose.
Bees are the original producers of invert sugar—honey. Sometimes commercial invert sugar is called artificial honey. In the early 1800s, M. Dubrunfaunt first explained the phenomena of sugar inversion. He hypothesized that when sucrose was heated with a dilute acid, it became a syrupy mixture of glucose and fructose in equal ratios.1
The name “invert” sugar was assigned in 1830, when Biot discovered that a plane of polarized light passed through a sucrose solution rotates it right, but when passed through the same solution heated with acid the light rotates left.1 The process of heating sugar with acid is therefore deemed sugar inversion.
As a baking ingredient, this form of sugar can be substituted for sucrose in almost every application. Functionally, it is preferred to sucrose because of its ability to:
Increase sweetness and balance acidity. It is sweeter than sucrose with a relative sweetness of 1232 compared to sucrose at 100
Invert sugar is a carbohydrate, supplying 4 calories per gram. It consists of simple sugars that are quickly absorbed in the bloodstream.
In 2016, FDA announced the new Nutrition Facts Label, which goes in effect beginning in 2020. At this time, added sugar, such as invert sugar, will be required to be identified on the nutrition facts label as added sugar.3
The conventional method to produce invert sugar is to hydrolyse sugar in the presence of acid and heat. This method, however, lacks efficiency because of a low conversion rate, high energy consumption and the development of off colors.4
Newer methods of producing invert sugar include utilizing the immobilized enzyme invertase to hydrolyze purified sugar. Also, scientists are investigating resin technology which is a more cost effective and efficient method to invert sugar cane juice.2
A baker must consider application and process when substituting invert sugar into recipes that call for sugar. It is not a 1:1 substitution. It is sweeter and has different properties.
These different properties, such as its higher affinity for water, make invert sugar preferred for low fat baked goods or soft cookies. Properties, such as invert sugar’s ability to enhance color, may prompt a baker to adjust cooking temperature and time to control browning reaction.
In the United States, invert sugar is affirmed as a Generally Recognized as Safe (GRAS) food substance. (21 C.F.R. § 184.1859 2018).
Stroud, J. “Commercial Invert Sugar”, Ind Eng Chem. 16 (3). 1924. Pp 307-310. DOI: 10.1021/ie50171a037
Gehlawat, JK. “New Technology for invert sugar and high fructose syrups from sugar cane”, Ind J Chem Tech. 8. 2001. pp. 28-32.