Pulses: Innovative Technology Delivers Higher Quality and Yields
08 April 20146 min reading
Head of Bühler’s Pulses Business Segment
Much of the developing world relies on pulses in order to obtain at least 10% of their daily energy intake and the demand for these invaluable products continues to increase. With this backdrop, pulse processors everywhere are being challenged to produce ever more and ever better pulse products, reduce their wastage and improve quality and consistency.
Humans have cultivated pulses for millennia. Most notably, archaeologists have found evidence of pulse production from the Ravi River area of Punjab in India, the seat of the Indus Valley civilization, dating back as far as c3300BCE. And, throughout the intervening centuries, pulses have continued to be an essential crop, which, along with all leguminous crops, are considered to be an important contribution to both food and nutritional security.
The Food and Agriculture Organization (FAO) recognises 11 primary pulses as leguminous crops that ‘produce between one and twelve seeds of variable size, shape, and colour within a pod’. They are highly prized for their nutrient content and are rich in protein, carbohydrate, vitamins and minerals.
The global pulse market was estimated at 70.4 million tonnes (mt) in 2012, with Canada accounting for approximately 35% of the global pulse trade. India, which contributes 23% of the total share of production of pulses, is expected to produce around 18-21 mt of pulses annually, up to 2016-17. However, in India alone, significant domestic shortages are anticipated, despite the Indian government’s interventions on pulse exports. To meet its shortfalls, India is likely to import nearly 17% of its requirements for pulse from countries such as Canada, Myanmar, Australia and some African countries, with yellow peas accounting for half and other pulses such as pigeon pea, black gram, mung bean and chickpea accounting for the remaining 50%.
MAKING THE MOST OF PULSES
Pulses, like any other grains, consist of starchy endosperms - a fat rich germ or embryo - and an outer hard protective layer, known as the husk or hull. However, unlike cereals such as rice and wheat, both the seed coat covering the grain and the underlying endosperm are firmly attached by a naturally occurring gum layer. The strength of this attachment varies with the differing types and the origins of the pulses, making them either easy or hard to dehull. In lentils and chickpeas, the gum layer is loosely bound, so they need relatively little pre-treatment. Pigeon peas and mung beans, on the other hand, require the addition of oil, tempering and intermediate drying, in order to remove their hulls.
In order to remove this seed coat and split the nutritious cotyledon into halves, pulses are milled – a process that improves the digestibility, texture, cooking quality and palatability of pulses.
Any equipment dedicated to the intricate processing of pulses must overcome the various adhesive forces within the grain, with minimum loss of the endosperm. So, knowledge of the properties and behaviour of the raw material is essential before the process flow of any plant can be determined if higher yields, better product quality and increased profits are to be achieved. Successful pulse processing plants are designed and engineered to produce not only the desired end product but also to handle the individual pulses being processed according to their specific requirements.
Pulse quality is often defined by appearance, and by the absence of foreign material, with pulses generally being separated into three grades: grade one promises a good consistent colour with sharp edges and no damage to the surface of the pulse; grade two includes grains that appear inferior, due to uneven splitting; and grade three consists of brokens, where half of the grain is missing and these are often sold as animal feed.
Ultimately, the criteria dictating the processing of any pulse is yield. High impurity levels and difficult processing parameters can lower yield, unless the pulse is processed with the utmost care. Modern technologies are now available to ensure gentle processing in combination with proper conditioning of the grain. These technologies, perfected over the years by experienced suppliers such as Bühler , can ultimately bring dramatic increases in yield. The automation and sophistication they bring to the pulse production process help reduce damage, provide far more efficient separation of impurities and far better recovery of valuable product such as lighter grains, which would otherwise be rejected into the waste stream.
As with all manufacturing industries, profitability and sustainability are critical factors for processors of agricultural commodities as they operate in an increasingly competitive world. In order to compete, pulse processors are adopting ever more modern and efficient processing methods in order to achieve the consistent product quality, reduce losses and increase productivity.
Complete processing solutions, supplied by recognised solution-providers, drawing on their experience and expertise in equipment integration, are taking today’s pulse processors to levels of productivity, consistency, safety and efficiency not possible before with individual pieces of machinery.
State-of-the-art automation and control systems can help pulse manufacturers achieve a higher degree of process flexibility and a higher output than ever before. They also help to reduce processors’ dependency on labour and offer smoother operation. The payback from an automated plant is rapid when calculated in terms of reduced downtime, reduced operational costs and reduction in manual intervention plus greater capacity.
A successful turnkey solution for pulse processing involves the full plant layout, from incoming raw material to delivery of the end product, including such elements as aspiration systems that keep the plant free from dust and maintain the optimum hygienic working environment inside the mill.
Although, general process flows remain unchanged, significant differences in the characteristics of pulses with different origins can be effectively absorbed into the design of a turnkey solution. These differing characteristics include changing impurity levels, moisture contents, size and yield plus the strength of gum layer between the seed and coat. The amount of damage or purity in the incoming material can vary significantly and this variation can be accommodated very effectively within a fully automated turnkey solution, which can also be programmed to respond to the required resting times, drying frequencies and hulling passes involved. A complete turnkey solution is designed and engineered to take each of these challenging factors into account. It can deliver on pre-cleaning and fine cleaning, grading, drying, de-hulling, splitting, optical sorting and polishing processes with the optimum in throughput, improved productivity and consistency in product quality, reduced operating costs, and boost to yields.
Understanding the evolving customer and market requirements is key. A technology provider needs to understand the intricacies involved in each stage of pulse processing, in order to increase yield and ensure a more profitable product, clean and free from foreign material, and consistently. The best pulse processing solution adapts to the complexities of different pulses, the varying qualities of incoming material and the requirements of different regions, in order to allow cutting edge technology to play its role in this crucial and ever expanding industry.
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