What is the role of converted sugar syrup in baking?
First of all, converted sugar has exceptionally good moisturizing properties to keep the cake fresh and moist; hygroscopicity is the property of absorbing water at higher air humidity, and humectancy is the property of absorbing water at higher humidity versus losing it at lower humidity. Secondly, it has anti-crystallization property. Therefore, it increases the smoothness of candies, frostings and syrups. This is the reason why acids like tartaric acid are usually added to the syrup, and in boiling, the acid converts some of the sugar so that there is no crystallization during heating to make candy or frosting.