# Food Processing with UHP Waterjets
## 4 Selected Cutting Applications
### Candy, Backed Food, and Sandwicles  
Waterjet cutting in the candy and bakery industries has a great advantage due to the relatively low forces involved in the cutting process. This results in no distortion to the food as demonstrated by Figure 24 for cutting cake and candy. Observe that there is no crushing or effects on the edges. Also, please observe the ability to cut through different constituencies such as nuts, taffy, chocolate, etc.  
[PERSON] [31] reported on the application of the diagonal cutting of egg and water cress sandwic with high-velocity waterjets with 0.1 and 0.15 mm diameters, as shown in Figure 25. He indicated that pressures up to 300 MPa are sufficient, and that jet coherency is of great importance for no wet edges. The production line uses four jets that slice four sandwic at a time and a robotic arm is used to pack four halves in one pack. This system produces 60 sandwic per minute. The cutting table was initially equipped with a line catcher. All four waterjets sprayed into one vessel which caused a rather high noise level. When four single-catcher cup units were used and synchronized with the corresponding jet, the noise level dropped by more than 6 dBA.  
Figure 24: Examples of candy and cake cutting.  
[PERSON] et al. [32] used slicing bread as a case study to identify the conditions that make the waterjet a perfectly clean tool. They concluded that these conditions are media filtration to 0.2 microns, the regular sanitation of the tubing, and controlling the ambient air to class 1000 or 100 based on the product. They also reported that the dominating factor for wetting the bread is pressure and then the cutting speed. Minimal moisture pick up was obtained at pressures in the range of 300 to 350 MPa and a speed in the range of 20 to 30 m/min.  
Bakeries use a variety of methods to cut cake such as wire, rotary wheels, reciprocating blades, and ultrasonic blades. These means take time to clean out and cause distortion while cutting, leading to reduced yield. They are also limited to straight line cutting. Waterjets avoid all these issues with significantly more productivity and thus can be found in commercial markets with automated machines that are cost effective. As described in the section above, either single, dual, or multiple jets are used. The most important factors in cake cutting are to use highly coherent waterjets and to prevent the splash back from the support structure. These issues have been addressed in machines such as those provided by ABI LTD (Richmond Hill, ON, Canada), Xilix (Hutto, TX, USA), and Metronics Technologies (Noain, Spain), using different approaches for the machines but with the same type of waterjet nozzles. Some examples of cutting cake are shown in Figure 26 below.  
Figure 26: Examples of backed foods cut with a waterjet.  
Figure 25: Sandwich cutting example.  
[PERSON] [33] quoted that a waterjet is an excellent choice when processing viscous, gelatinous, and multi-ingredient food products such as baked goods and confectionery such as Danishes. Cutting pizza is of course possible with excellent results but is not practical except on a large scale where pizza is frozen after cutting. In this case, every slice will be perfectly separated after heating.