Manufacturing donuts with less fat and sugar is a must. However, this is just the starting point as unusual shapes, new flavor experiences, creative textures and hybrid formulations are on the rise. What do they have in common with muffins and cupcakes? Aside from striving for unique creations, or rather because of it, there is a flexibility push on the equipment supporting their manufacturing.
Smart donut lines
RONDO‘s fully automated donut lines allow output rates from 6,000 to 30,000 units per hour. They are equipped with IIoT solutions which allows them to be monitored remotely, parameters including line capacity, actual machine status and line settings. “Furthermore, the logged data can be used to optimize the production and the process reliability of the line,” the specialist points out. These donut lines are specialized to suit two manufacturing styles.
+ The direct dough band method uses a dough band former to form a thick and narrow dough band out of the bulk dough. This process helps to preserve the structure of the dough. Several forming units are used afterward (i.e., a satellite head, a cross roller and a calibrator) to bring the dough band to the desired thickness and to increase its width on the band. Gentle sheeting and forming is important in this step, stresses Alexander Weissbach, head of Technology and Product Management, and head of the Dough-how Center at RONDO Burgdorf AG.
The dough band former used at the beginning of the process is the key to success, he explains, as it is within this first step that the final quality and weight accuracy are defined. The dough band former must be accurately balanced to process dough gently while forming a compact dough band. The dough band formers Smartfeeder and MIDOS were designed for such delicate doughs. The satellite head, the first station where the rough band is thinned, also plays an important part in dough quality. “Reducing the dough band thickness too aggressively will break the dough structure and the volume of the final product will be lowered. The satellite head of the Smartline can be adjusted in three ways to reduce the force during this step: the roller gap, the speed difference between the bottom roller and satellite head, and the tilt angle between the bottom roller and satellite head. The last feature is unique and patented. Changing the tilting angle will reduce the force during the reduction step. Therefore, the dough structure will not be destroyed. Furthermore, the weight accuracy can be improved,“ Weissbach tells us.
+ By comparison, a line using the laminating method is equipped with one or two laminating stations (the final section remains unchanged). The additional lamination sections will influence the structure of the dough by creating additional cross-linkages in the gluten network. Therefore, the dough band gains more stability and the volume of the donut will be bigger.
Both methods will result in a consistent dough band for further processing – cutting the donuts into the desired shapes. “A very important side effect of the dough sheeting process is that the donuts absorb less fat during the frying process. This is due to the gentle sheeting process, which results in a dough band with a smooth surface and an intact gluten structure, ensuring that the surface of the dough band is not porous,” RONDO’s expert explains.
Answering requests
RONDO observes special donut shapes are increasingly in demand, and so is the flexibility to produce them all on one line, which also makes fast changeovers a necessity. Switching between different product shapes, sizes and weights can be done within minutes on RONDO lines, which are designed for tool-less changeovers. All line settings are stored in the PLC. Selecting a new recipe will automatically adjust the line according to the recipe details.
Manufacturers also tend to prefer working with softer doughs and pre-proofed dough for more flavorful products. The dough band method has several benefits concerning all these requests: softer and pre-proofed dough can be gently processed without sticking on the line and damaging its structure. RONDO’s guillotines can also be equipped with different stamping dies, to cut donuts into various shapes.
Another requirement is automation, as RONDO sees an increasing number of manufacturers increasing their capacity and automation level. This means synchronizing with suppliers of up- and downstream equipment, setting up common interfaces to optimize workflow. For example, RONDO’s make-up lines end with the panning of the donuts onto the proofer flights. In the absence of design guidelines for the proofers and the proofer flights, the company designs a modular panning machine that can be used to feed every proofer on the market.
In the long term, RONDO anticipates that IIoT systems that control and optimize line performance are the key figures. “Improving and optimizing changeovers and the production sequences will help maximize the efficiency of the line,” Weissbach anticipates.
