Technical profile: wheat debranning process
March 01, 1996
by Teresa Acklin
Contributed by suppliers, technical profiles feature new technology, products, specific applications or proprietary concepts. This material was prepared by Satake U.K. Ltd., Stockport, U.K., a part of the Satake Corp., Hiroshima, Japan.
The Satake Corp., which this year celebrates 100 years of service to the cereal processing industry, introduces PeriTec a flour milling system for the 21st century.
The concept of debranning wheat prior to milling has fascinated researchers for many years. The logic of this approach is inescapable, but the development of a satisfactory debranning process has hitherto proved elusive. Without an effective debranning process, one which achieves a high degree of bran removal with minimal endosperm loss, the potential advantages in the subsequent milling process cannot be fully realized.
Employing its extensive experience in cereal de-hulling, technology which has taken Satake to undisputed leadership in rice processing systems, Satake has developed a successful wheat debranning technique. The heart of the system is the new VCW Debranner, a simple, robust machine that decorticates wheat in a single pass, without elaborate tempering systems or excessive power consumption.
Once it was apparent that an effective debranning system had been achieved, Satake set out to optimize the attendant milling flow. This enormous undertaking involved the building of a complete commercial size research mill at Satake's Hiroshima facility as the vehicle for an exhaustive development project employing more than 70 engineers and millers on a full-time basis.
Starting with durum wheats and then progressing to a representative range of common wheats hard, semi-hard and soft varieties comprehensive performance data were gathered and flow-sheet optimization was conducted.
In close partnership with selected customers around the world, Satake introduced PeriTec into the marketplace to test end-user reaction. Commercial mills producing semolina, bread flours and biscuit flours are in full operation, and more are under construction. The results from the operating mills are such that the unrestricted launch of the PeriTec system has been authorized by Satake management.
PeriTec requires no special wheat preparation. Cleaning is carried out in the usual way according to wheat variety and local conditions, although in the PeriTec process, the bran is removed prior to milling so that final scouring can be eliminated, even where micro-bacterial activity is a concern.
The debranning process begins with the addition to the wheat of a small amount of water, followed by a short dwell time in a holding bin immediately prior to the VCW Debranner. The VCW Debranner utilizes both abrasion and friction to strip the bran layers from the endosperm in a controllable manner. The debranned wheat leaving the machine is aspirated and hydrated before delivery to the first break passage of the mill.
The Satake post-debranning hydration system provides accurate control of finished flour moisture because the debranned wheat can be effectively hydrated with very short absorption times.
The PeriTec milling process is greatly simplified. Because the majority of the bran has been removed prior to the mill, the break system is very limited. There is no need to scrape endosperm from bran so that the entire tail-end of the traditional break system is rendered redundant.
Additionally, with the bran layers removed, the PeriTec break system releases a very high quantity of practically pure semolina, which is graded and sent to the head reduction system.
Where purifiers are employed, in durum semolina mills for instance, they perform more effectively on these uniformly clean products and at considerably higher unit capacities. For this reason it has been possible, by incorporating PeriTec, to increase the capacity of existing semolina mills by as much as 80% without adding conventional milling equipment.
It is perhaps appropriate that PeriTec should have been developed in Japan, where flours are produced to the world's most demanding quality standards, for it is in the aspect of flour quality that PeriTec makes its major contribution.
All mills employing PeriTec produce a very flat ash curve this is entirely logical in a system where most of the bran has been removed prior to the mill and it is this feature that allows the production of exceptional rates of low-ash patent flour. That such quality should be achievable on a simple short flow, minimizing investment as well as on-going operating expense, demonstrates what a remarkable breakthrough PeriTec represents.
An aspect of bread flour quality that is difficult to define but of fundamental importance is baking quality. PeriTec allows the inclusion in the finished flour of controllable quantities of the aleurone layer with its intriguingly beneficial effect on bread quality. In traditional mills the aleurone layer is not encountered until the tail end of the break system where it is contaminated by bran powder and condemned to the low-grade flour stream or the bran bag. The inclusion of aleurone material from the PeriTec system is not detrimental to color grade although this material has a high inherent ash content.
The bran that is removed by the VCW Debranner is fine and powdery, not suitable for the production of the coarser wheatmeals, but the VCW Debranner eliminates the capital cost and ongoing energy consumption of bran grinding. Where wheatmeal represents a significant part of production, alternative arrangements are made to provide for bran of the appropriate specification.
There are no restrictions on the manner in which the PeriTec process can be housed. Conventional multi-floored buildings of concrete, brick or steel as well as modular platform designs are applicable. The reduced equipment content and flow simplicity of PeriTec mills minimize building investment and keep conveying system power consumption low. PeriTec also can be added to existing mills to provide increased capacity economically and with minimum disruption.
PeriTec is the milling system of the 21st century, available now to give better products and a higher return on investment.