Moisture Content in Molding Starch
Confectionery items such as jelly bean centers, candy corn, marshmallows, starch gums, caramels, nougat, gummies and cream centers may be manufactured using starch molding techniques. At several stages during the manufacture of these products simple holding operations are required, variously called setting, stoving, resting, curing, drying, aging or conditioning times.
Confectionery manufacturers are interested in reducing holding times to improve productivity and reduce work-in-progress. However, for any one product, there are changing physical processes occurring during these periods. The phenomena involved may include cooling, drying (moisture removal), moisture equilibration or redistribution, gelation (setting), crystallization or a combination of these depending on the product.
The rate at which starch adsorbs moisture is comparatively slow and the dynamic relationship of the product; the rate determines productivity of the process. Unlike in most foods, water is a minor constituent of confectionery — but one that has a major impact.
The MoistTech IR3000 On-Line Moisture Sensor is accurate to laboratory standards with the added benefit of making a continuous measurement over the flow of product at critical locations in the process, both at intermediate and final moisture levels. Fast and accurate moisture measurement is crucial for control of starch molding production plants and for the safe storage and transportation of the final product.
For most starch molded confections, the moisture content of the starch should be in the range of 5.5 to 7.0 percent. Although there are some marshmallow type products that require starch moisture as low as 5.0 percent, most gummies, jellies, jujubes and other specialty items will work best if the moisture is kept in the 5.5 to 7.0 percent range. If the moisture level drops below 5.5 percent, the starch loses some of its ability to hold the shape of the molds because it becomes too dry and crumbly.
In addition, because of the lower amount of moisture present, it becomes dustier and thus a potential explosion hazard. If the moisture level rises above 7.0 percent, the starch becomes less effective as a curing aid for the candy. Because the starch can only hold onto so much moisture, the more that is present at the time the slurry is cast into it, the less it will be able to absorb from the candy during the curing cycle. In fact, if the moisture level of the starch is too high, and the casting solids of the slurry are too low, the excess moisture from both sides will react in a way that will cause some of the molding starch to adhere to the surface of the finished confection.