Karl Fischer homogeniser is a faster alternative to the conventional loss on druying technique for the determination of the water content of sweets
Humans are all, secretly or openly, obsessed with sweet things - and we always have been.
Cavemen who dug honey from bee hives were the first to enjoy a sweet treat.
Recorded history traces sweets (or candy) to the Egyptians 3500 years ago.
The Aztecs mixed chocolate with blood in sweet libations to their gods. During ancient times the Egyptians, the Arabs and the Chinese prepared confections of fruit and nuts candied in honey.
In Europe during the Middle Ages, the high cost of sugar made sugar candy a delicacy available only to the wealthy.
Cacao, from which chocolate is made, was discovered in 1519 by Spanish explorers in Mexico.
The scientific name of the cacao tree's fruit is Theobroma Cacao, which means 'food of the gods'.
Boiled sugar candies were enjoyed in the seventeenth century in England and in the American colonies.
By the mid-1800s, more than 380 American factories were producing candy - mostly 'penny candy' which was sold loose from glass cases in general stores.
Sweet-making developed rapidly into an industry during the early nineteenth century through the discovery of sugar beet juice and the advance of mechanical appliances.
Homemade hard candies, such as peppermints and lemon drops became popular in America during that time.
Victorian sweets magnates built the towns of Bournville and Hersheyville from fortunes made through successful candies, and even today the manufacture of sweets is shrouded in a level of secrecy that would make Willy Wonka proud. Sweet formulations vary tremendously, but the basic ingredients remain the same.
Most sweets contain most or some of the following: cane sugar, corn syrup/cream of tartar, liquid (water or milk), fat, egg whites, gelatin, flavourings, and colourings. When cane sugar is heated, the second action which you can't see is the breakdown of sucrose into its two simple sugars - dextrose and fructose.
Acids or enzymes accelerate the process, such as adding vinegar.
A number of familiar products rely upon inverted sugars.
Fondant centres, fudge, butter confectioners, chewing gum, jellies, caramels and toffees, hard creams, high boiled sweets, butterscotch, marshmallow and soft creams all are results of this inversion process being carefully controlled. High levels of inverted sugar, particular fructose, pick up moisture from the air and the water is deposited on the surface of the candy.
This water leaches sugar from the candy surface, and a layer-by-layer change in the candy can be seen when water is present.
Too much water can cause the sweet structure to be unstable and the sweet may well become too sticky.
The level of water is therefore critical in the manufacture of these sweets. Karl Fischer titrations are used for water content analysis of these sweets, as it provides a quick, reliable and accurate method.
For products that do not release water readily, such as sweets, chocolate, peanuts, almonds and fudge, water content has been traditionally carried out by loss on drying (LOD) which can take up to two days for some products to be completely dry. Metrohm has an alternative, using the Karl Fischer Homogeniser system.
The sample is physically broken down to a pulp by maceration, chopping and grinding of the sample in situ, in a sealed Karl Fischer vessel at an elevated temperature, typically 50C.
This seal is important because, if this breakdown of the sample is carried out manually, samples can gain or lose water depending on the relative humidity during this process.
With the sealed vessel this cannot occur.
The maceration time, extraction time and the automatic stop criteria functions of the titration are controlled automatically by the 841 Titrando.
Typical analysis times are three minutes and the system uses small amounts of solvents (less than 70ml) for the determinations.
