Glucose syrup

Glucose syrup, also known as confectioner's glucose, is a syrup made from the hydrolysis of starch. Glucose is a sugar. Maize (corn) is commonly used as the source of the starch in the US, in which case the syrup is called 'corn syrup', but glucose syrup is also made from potatoes and wheat, and less often from barley, rice and cassava.p. 21 Glucose syrup, also known as confectioner's glucose, is a syrup made from the hydrolysis of starch. Glucose is a sugar. Maize (corn) is commonly used as the source of the starch in the US, in which case the syrup is called 'corn syrup', but glucose syrup is also made from potatoes and wheat, and less often from barley, rice and cassava.p. 21 Glucose syrup containing over 90% glucose is used in industrial fermentation, but syrups used in confectionery contain varying amounts of glucose, maltose and higher oligosaccharides, depending on the grade, and can typically contain 10% to 43% glucose. Glucose syrup is used in foods to sweeten, soften texture and add volume. By converting some of the glucose in corn syrup into fructose (using an enzymatic process), a sweeter product, high fructose corn syrup can be produced. It was first made in 1811 in Russia by Gottlieb Kirchhoff using heat and sulphuric acid. Depending on the method used to hydrolyse the starch and on the extent to which the hydrolysis reaction has been allowed to proceed, different grades of glucose syrup are produced, which have different characteristics and uses. The syrups are broadly categorised according to their dextrose equivalent (DE). The further the hydrolysis process proceeds, the more reducing sugars are produced, and the higher the DE. Depending on the process used, glucose syrups with different compositions, and hence different technical properties, can have the same DE. The original glucose syrups were manufactured by acid hydrolysis of corn starch at high temperature and pressure. The typical product had a DE of 42, but quality was variable due to the difficulty of controlling the reaction. Higher DE syrups made by acid hydrolysis tend to have a bitter taste and a dark colour, due to the production of hydroxymethylfurfural and other byproducts.p. 26 This type of product is now manufactured using a continuous converting process and is still widely used due to the low cost of acid hydrolysis. The sugar profile of a confectioner's syrup can also be mimicked by enzymatic hydrolysis. A typical confectioner's syrup contains 19% glucose, 14% maltose, 11% maltotriose and 56% higher molecular mass carbohydrates.p. 464 A typical 42 DE syrup has about half the sweetness of sugar,p. 71 and increasing DE leads to increased sweetness, with a 63 DE syrup being about 70%, and pure dextrose (100 DE) about 80% as sweet as sugar.p. 71 By using β-amylase or fungal α-amylase, glucose syrups containing over 50% maltose, or even over 70% maltose (extra-high-maltose syrup) can be produced.p. 465 This is possible because these enzymes remove two glucose units (i.e. one maltose molecule) at a time from the end of the starch molecule. High-maltose glucose syrup has a great advantage in the production of hard candy: at a given moisture level and temperature, a maltose solution has a lower viscosity than a glucose solution, but will still set to a hard product. Maltose is also less humectant than glucose, so candy produced with high-maltose syrup will not become sticky as easily as candy produced with a standard glucose syrup.p. 81