By: Barbara Kästl *
Profit from the full potential of the HOSOKAWA ALPINE food technology
Spice grinding is a process with highest requirements for machines and plant systems. The various sizes, essential oil and fiber contents of the products influence the size reduction process in different ways. Hosokawa Alpine, as a leader in powder processing and particle size reduction technology, supplies complete systems for the whole range of spices and dried vegetables as well as for every fineness demand and end application, whether it be for sauces, soups, cheese, sausages, spice blends, bakery products or immediate consumption.
Nutmeg is, among saffron or vanilla, an exclusive product in the world of spices (see Figure 1). One of its characteristics is a high fat content with about 36.3g per 100g and a resulting heat sensitivity in the milling process. Because of its value, an energy efficient grinding system with continuous operation over long periods is required by the industry. Hosokawa Alpine offers the Contraplex pin mill CW II for greasy and heat-sensitive products with a re-designed classic spice grinding process conform to international food safety standards and European safety guidelines.
A high-tech grinding system for fatty products
The Alpine Contraplex pin mill CW II is an advanced high-tech grinding system for fatty products with high finenesses. The latest generation was refined in collaboration with our customers to h be st grinding results in a high quality. The finen esses are achieved by two pin discs in a counter-rotating mode with extreme high relative speeds up to 24 0 m/s, measured at the outermost pin rows. The developing centrifugal forces in the wide chamber of the mill create a selfcleaning effect and avoid an agglomeration of the nutmeg powder for a guaranteed gentle and long-time milling process. The improved door design gives easy access to the grinding area for maintenance and cleaning after the production process (see Figure 2).
Cryogenic grinding for high product qualities and a long lifetime
The high fat content of the nutmeg is the biggest challenge to pass in the milling process. On the one hand, evaporation of essential oils (6-15%) must be minimized because the oil content of the spice defines its market price. On the other hand, the high fat content can cause a build up during the milling process and can clog the mill in the worst case. Due to this, the Hosokawa Alpine cryogenic grinding process with CO2 or LN2 is a proven technology that makes the nut easier to mill. A screw cooler cools the feed product in a nitrogen bath down to minus 30 to minus 80 degrees. A cryogenic control valve unit for precise dosing of the cooling agent, as well as a temperature control and a O2 monitoring enable precise adjustments and control. The cooling process gives the nutmeg a porous structure, which makes it easier to break and less sticky. A purge air system free of dead spaces around the new, gearless drive avoids build ups of the product (see Figure 3).
The fineness of the product is variable, depending on the temperature, particle size and pre-treatment (see Figure 4).
* The Author Barbara Kästl is Sales Manager Business Development, Food Division Hosokawa Alpine Aktiengesellschaft in Augsburg, Germany