Gelling Properties and Drying Behavior of Gelatin-Based Candies

Gelatin is widely used in the confectionary industry to produce gummy candies. The project investigates its physical, chemical and technological properties and its behavior during candies processing. Gelling behaviour of gelatins with different Bloom was studied determining the least gelation concentration (LGC). The binary water–gelatin systems LGC depended on the Bloom strength: Blooms 275 gelatin formed a gel already at 0.5% (w/v) whereas 250 and 200 gelatins required 2.5% (w/v). This is consistent with the stronger gelling ability expected from higher-bloom gelatin. In the ternary systems containing 32% (w/v) sugar the three gelatins gelled at 1.5% (w/v) with no significant difference between glucose and sucrose. In blooms 250 and 200, the sugar lowered the LGC from 2.5% to 1.5%, agreeing with previous studies where co-solutes favour gelatin gelation by decreasing the water availability, hence, increasing the effective gelatin concentration [2]. No effect of sugars on the LGC of gelatin Bloom 275 was observed, Regardless of the system, the gel strength — estimated visually after the LGC test — increased progressively with gelatin concentration, from a weak gel close to the LGC to a firm gel at the highest concentrations (i.e. 8.5–10% w/v). At pilot scale, the drying of different types of gummies was studied in a pilot stoving unit, monitoring temperature and relative humidity in parallel with the evaluation of the product properties (moisture and aw) over time. On the drying cycle, 50 % decrease in total moisture loss occurred within the first 20 % of the process time. A progressive decrease of the moisture loss rate was observed with no constant-rate period, consistent with the diffusion-limited drying of starch-moulded candies [1]. These results relate the behavior of the product processed industrially with the technological functionality of gelatin, providing a basis for the optimization of the candies drying process.