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We need a protein revolution

In order to supply a growing world population with high-grade protein, pulses, algae, and insects will soon play a key role. Bühler is developing solutions to process them.

Text: Boris Schneider - Pictures: Ralph Richter

Meat substitutes made of peas, pasta containing Chlorella protein, black soldier fly meal as feed for aquacultures: In order to supply a growing world population with protein, new and innovative approaches are required today. Each adult needs about 60 grams of high-grade protein per day. To feed the global population, agriculture produces some 525 million tonnes a year of plant protein as found in corn, rice, wheat, or soybeans. “Our calculations show that by 2050 an additional 265 million tonnes of protein will be required annually to feed the growing population,” says Andreas Baumann, expert protein value chain at Bühler. To avoid a gap, global production must therefore increase by 50 % over today’s level.

Closing the protein gap
The looming protein gap is a serious challenge for human nutrition. For even today, in spite of intensive farming, mass animal breeding and fishing, our protein supplies are not sustainable: “Two-thirds of all vegetable proteins produced end up in the stomachs of livestock such as cattle, pigs, poultry, or fish. And the transformation from plant protein into animal protein is not very efficient,” explains Baumann. Cattle need up to 20 kilograms of feed to produce one kilogram of body mass. The yield in edible meat is even smaller.

Enough protein for 18 billion vegans
Up to 50 % of the extra protein needed by 2050 could be obtained by eliminating waste. Today, some 30 % of raw materials is lost, either because foods spoil, for example due to improper storage, or because consumers throw them away. The shortfall could also be reduced by a stronger focus on a vegetable-based diet. “If we were all to become vegans, we could provide food for 18 billion people with the protein volume produced today,” says Baumann. However, this is unlikely to happen: As the emerging countries become more prosperous, meat consumption is set to rise by as much as 44 % by the year 2050.

There is no way around the increased use of vegetable proteins. High hopes are pinned, among other things, on pulses. “These gluten-free sources of protein and fiber are appreciated by health-conscious consumers,” explains Baumann. In Asia and Africa chickpeas, lentils and beans have long been prominent staples. In Europe and North America they have somewhat sunk into oblivion. Thus, production volumes are rather small: Worldwide production today is just 77 million tonnes per year – 15 times less than corn and ten times less than rice or wheat.

The potential of pulses is still far from exhausted. And the processing technologies are available today: Bühler offers solutions for all major process steps such as cleaning, hulling, splitting, and sorting. With the Pulsroll Pulse Huller, for instance, the hull of different pulses can be removed in an efficient, gentle and hygienic way. “Our processing technologies are tailored to different requirements with regard to capacity and safety. They easily meet the demand of highly regulated EU and US pulse processors,” explains Baumann.

New products make pulses appealing
A crucial point is downstream processing: “A criticism often leveled against pulses in the western hemisphere is that they require a lot of time to prepare and can cause bloating,” says Baumann. The challenge for the industry is to develop products with a high level of acceptance. Lentils and peas, for instance, could be transformed into high-protein flours for use as additives in bakery products or pasta. This is also interesting from a nutrition physiology point of view: The amino acids contained in pulses and wheat are highly complementary and, in their combination, are comparable to animal protein.

It is also possible to produce pasta with an attractive flavour and texture using only pulses. The “al dente” structure, which is typical for wheat pasta, however, must be obtained through the modification of the starch. Like in all gluten-free pasta products, the starch must perform the function of the gluten. With the Polymatik press, Bühler provides a production solution, which enables pulses and other raw materials to be processed into savory pasta products with the typical bite.

Last but not least, pulse flour can also be used to manufacture meat substitutes: “With the extrusion technology from Bühler, so called textrudates can be produced,” explains Baumann. Thereby, a protein concentrate is heated in the extruder. At high temperatures, the native protein chains denaturate. Upon exiting the die, the proteins are realigned and cross-link themselves. These textrudates have a fibrous structure that comes very close to that of animal meat and they feel like real muscle meat when chewed. “Such novel products could make pulses more attractive for a wider circle of consumers because they do not have to change their dietary habits,” adds Baumann.

Soybeans and fishmeal are unsustainable
In the medium to long term, however, the use of new raw materials such as algae or insects is inevitable. They could, for example, be used as sustainable alternatives to feed based on, say, soybeans and fishmeal. Today, almost 80 % of the global soybean harvest is processed into animal feeds. “The criticism for soy is directed towards the deforestation taking place, for example, in Brazil to generate new farming land,” says Baumann. Fishmeal, on the other hand, is largely made from wild-caught fish, exacerbating the problem of overfishing. In addition to sustainability aspects, economic reasons speak a clear language as well: The prices for soybeans and fishmeal tripled between 1994 and 2014.

Microalgae such as Chlorella and Spirulina stand out as high-grade sources of protein: “Their production does not compete with existing farming land. They grow quickly and take up very little space,” says Baumann, summing up their main advantages. Algae are cultivated in open ponds, or closed systems with tubes, bags, or tanks. The famous “Algae House” in Hamburg, Germany, even uses its facade for this purpose. One kilogram of algae protein can be produced on an area of only 1.6 square meters, compared with the roughly 50 square meters required by pigs for the same output.

227_mod_Imagebox 26554 The Bühler expert for the protein value chain Andreas Baumann examines meal worms.

Gentle rupturing of the algae cell walls
Industrial-size plants for cultivating and processing on a large scale still remain to be developed. One critical processing step is the rupturing of the robust algae cell walls. In a research project, Bühler has demonstrated that agitated bead mills are the most cost-efficient mechanical method for this purpose today. This wet grinding technology is also used for the dispersion of high quality printing inks or coatings. Numerous small grinding beads are put into motion by a rotor. Stresses between the beads lead to the fine dispersion of the product. “A key aspect are shear forces induced by setting the liquid into motion, which allow a gentle disruption of the algae cell walls,” adds Baumann.The protein contained in these cells can, for example, be processed into animal feed. Bühler provides solutions for the conditioning of the raw materials, as well as the extrusion of feed pellets for domestic or farmed animals. Other applications are found in the domain of food: Algae proteins allow the production of additives for bakery products, pasta, or snack foods as well as meat substitutes. Besides their different proteins, algae also contain high-grade polyunsaturated fatty acids or pigments, which can also be profitably utilized.

Insects as an efficient protein source
Like algae, insects offer much market potential. Mealworms or larvae of the black soldier fly can be fed with industrial by-products or even with waste. Moreover the feed conversion is very high. It needs only two kilograms of feed to build up one kilogram of insect mass. Like algae, they take up very little space: On one square meter, one kilogram of insect protein can be produced. Even though insects are consumed by humans in certain regions of the world such as Asia, it is as yet uncertain as to whether western consumers would accept insect-based food products. The primary focus for the time being, therefore, is on processing them into feed. “The protein in insect meal is very similar to that of fishmeal. It could be readily applied in feed for aquaculture and thus help to relieve pressure on natural fish populations,” says Baumann.

Until insects contribute substantially to feeding humans and animals, however, many challenges need to be adressed. In some countries, animal proteins have been banned from use in livestock feed since the BSE crisis. Also the large-scale rearing and processing of insects is still uncharted territory. “Bühler is currently setting up a pilot facility with a partner in China for processing fly larvae and mealworms on an industrial scale. The aim is to produce insect meal as a replacement for fishmeal plus a high-grade fat with properties similar to those of palm kernel oil,” explains Baumann.

The protein market will definitely become more diversified over the next few years. As the market and technology leader in the field of cleaning, drying, sorting, grinding, and extrusion processes, Bühler will play a key role in the processing of alternative sources of protein such as pulses, algae, or insects. “While the potential of pulses can already be used today, we are now developing the solutions required so that algae and insects can soon contribute to providing food for humans and animals,” Baumann concludes.