Monday, February 21, 2011

Syrup

A syrup is a thick, viscous liquid consisting primarily of a solution of sugar in water, containing a large amount of dissolved sugars but showing little tendency to deposit crystals. The viscosity arises from the multiple hydrogen bonds between the dissolved sugar, which has many hydroxyl (OH) groups, and the water. Syrups can be made by dissolving sugar in water or by reducing naturally sweet juices such as cane juice, sorghum juice, or maple sap. Corn syrup is made from corn starch using an enzymatic process that converts it to sugars. Technically and scientifically, the term syrup is also employed to denote viscous, generally residual, liquids, containing substances other than sugars in solution.

Types of syrups:

1. Non-medicated syrup:
The syrup employed as a base for medicinal purposes consists of a concentrated or saturated solution of refined sugar in distilled water. The "simple syrup" of the British Pharmacopoeia is prepared by adding 1 kg of refined sugar to 500 mL of boiling distilled water, heating until it is dissolved and subsequently adding boiling distilled water until the weight of the whole is 1.5 kg. The specific gravity of the syrup should be 1.33. This is a 66° Brix solution.

2. Medicated syrup

 

Composition of medicated syrups
Medicated syrups are aqueous solutions containing sugar and at least one water soluble active ingredient.
The sugar is mainly used to:
  • Preserve the finished product
  • Aid in masking the unpleasant taste of the active ingredient(s)
  • Enhance the flavour.
The concentration of sugar must approach but not quite reach the super-saturation point: the sugar concentration should be between 65 and 67% in weight. A lower percentage of sugar makes the syrup an excellent nutriment for yeast and other microorganisms. A sugar saturated syrup lead to crystallization of a part of the sugar under conditions of changing temperature.
Syrups may also contain the following excipients:
  • Sugar polyols like glycerol, maltitol and sorbitol
  • Preservatives like parabens and bezoates and antioxidants like butylated hydroxytoluene (BHT) and sodium metabisulfite.
  • Acids like citric acid to prevent the recrystallisation of sugar
  • Buffering agents
  • Chelating agents like sodium ethylenediaminetetraacetic acid (EDTA)
  • Flavouring agents and flavour enhancers
  • Colouring agents
  • Ethyl alcohol (3-4% in volume).
The syrup may also be sugar-free. The sugar is then replaced by sugar substitutes like the sugar polyols such as glycerol, isomaltol and sorbitol or artificial sweeteners like aspartame, neotame, sucralose and acesulfame potassium mixed to thickening agents like polyvinylpyrrolidone or polysaccharides like carrageenan, xanthan gum, and cellulose ethers. Sugar-free syrup will not contribute to dental caries.

Preparation of medicated syrups

Syrups are mainly prepared by the following method:
  • Dissolve ingredients in purified water and because the sugar decreases the solubilizing properties of water, it is added generally at the end.
  • Heat and/or agitate actively until the dissolution of all ingredients. If at least one of the ingredients is sensitive to temperature, mixing should take place without heating.
  • Strain if needed
  • Add sufficient purified water to make the right weight or volume.
Simple Syrup:

A basic sugar-and-water syrup used to make drinks at bars is referred to by several names, including liquid sugar simple syrup, sugar syrup, simple sugar syrup, gomme, and bar syrup. Simple syrup is made by stirring granulated sugar into hot water in a sauce pan until the sugar is dissolved and then cooling the solution. Generally, the ratio of sugar to water can range anywhere from 1:1 to 2:1.
Simple syrup can be used as a sweetener. However, since it gels readily when pectin is added, its primary culinary use is as a base for fruit sauces, toppings and preserves.

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