Development chefs do an excellent job of creating new cooked foods with high standards of taste, texture and nutritional performance, but the problem has always been to scale-up the process without compromising these characteristics.
Compared with saucepans used in development kitchens, industrial-scale steam-jacketed kettles have a lower temperature differential that results in a slower rate of heating.
If quantified in terms of cook values (or
Co numbers), the optimum for a particular product achievable in a saucepan might be 2030, whereas the full-scale plant would typically only achieve 100 or more, with correspondingly lower qualities.
Scraped surface heat exchangers are sometimes cited as a better alternative to kettles, though they are significantly more complex, expensive, difficult to clean and deliver only marginal improvements.
However, the PDX Sonic 25 enables Co to be accumulated as fast and in as controllable a manner as in a saucepan. For example, trials have shown that a 120kg batch of smooth curry sauce takes six minutes to mix and cook with a PDX Sonic25, which compares with around one hour using conventional technologies.
Significantly, the process will not damage even the most delicate particulates and, unlike conventional methods of steam injection with high thermal gradients, thermal shock is reduced and cook-on eliminated. As a result, food quality is maintained while cleaning times are reduced.
As the product flows through the PDXSonic25, additional ingredients can be entrained virtually instantaneously, so each can achieve its own optimum Co value. Mixing is extremely even, despite the short timescales. Tests have shown that the PDXSonic25 cooks-out starches instantly at 70ºC without a 10minute dwell time, saving both time and money.
Steam is introduced into a special annular conditioning chamber that is wrapped around the core of the PDX unit. From here, it is expanded into the process fluid at speeds exceeding 1000m/s. The combination of this momentum transfer and the controlled collapse of the steam sees the process fluid accelerated to over twice the speed of sound in a supersonic and gaseous phase until the condensation shockwave hits. This supersonic phase is highly energetic and causes simultaneous mixing, homogenisation, heating and pumping actions to take place.
A vital aspect of the technology is that this supersonic region can be controlled enabling different conditions to be set, including homogenisation or, alternatively, low shear to ensure particulate integrity. Flow rates and temperature rise can also be controlled. Importantly the geometry of the technology enables this to happen with no constrictions or moving parts.
With such a fast, versatile, easily cleaned, scaleable system, food processors can benefit from substantially increased productivity. But a further major attraction is the ability to produce recipes and qualities that are simply not feasible using conventional technologies.
Inside PDX Sonic25
Pursuit Dynamics has developed the PDX technology over the past four years at a cost in excess of £6.5million. The company is based in Royston, Hertfordshire, UK.
The company says it has taken the technology to the next level with the launch of the PDXSonic25. This self-contained, fully integrated processing system combines a 500litre vessel, in-feed entrainment hoppers and a programmable electrical control system.
With the potential to revolutionise traditional liquid food production with its supersonic shockwave technology, the PDX Sonic25 has the power to reduce total process times by up to 95percent and reduce cleaning times by 80percent, while protecting the finished quality of liquid foods.
It replaces conventional multi-stage food production processes with a compact, self-contained production system that has a footprint of 3.6mx2.2mx2.0m. The fully automated batch processing system can mix, pump, homogenise and cook ingredients simultaneously, with the patented steam-injection shockwave technology delivering unrivalled rates of heating. Yet the process will not damage even the most delicate particulates and, unlike conventional methods of steam injection, with high thermal gradients, thermal shock is reduced and cook-on eliminated.
As a result, food quality is maintained whilst cleaning times are reduced. CIP time is further reduced since there are no moving parts in the PDX processor a factor which also reduces maintenance, downtime and through life costs.
Steam supply is via a one inch BSPP connection, with the process typically consuming 3.0kg/minute of steam flow at a nominal 6.0barG delivery pressure. According to the company, the steam-injection technology delivers phenomenal rates of heating for example raising the temperature of 500litres of water from 15°C to 85°C in just 16minutes at an industry standard steam cost of 52pence so reducing overall processing times and reducing energy requirements. Water supply is via one inch BSPP coupling, and nominal flow is 15000litres per hour.
The PDXSonic25 is constructed to the most demanding food standards. All components in contact with processed fluid are made from AISI316 stainless steel, while all other components are made from AISI 303/304 as a minimum. Fluid inlet and outlet connections are via 1.5inch TRI-Clamp union fittings as standard, SMS, RJT or flange type inlet and outlet connections as options.
Stuart Rigby is Head of Technical Sales with Pursuit Dynamics, tel +44 (0) 1763 250592, e-mail info@pursuitdynamics.com, or visit www.pursuitdynamics.com.
