Traditionally, the pit and seed of olives have been discarded as waste products, unsuitable for consumption or further use. However, new optical sorting technology, developed by the Bühler Group, is able to extract the seeds from inside the olive pits, which can then be consumed raw or toasted as a snack.

The advantages of this sorting technology are twofold: waste products are avoided, and olive seeds contain up to 100 times more polyphenols and antioxidants than olive oil, in addition to high levels of good quality dietary fibre. We find out more about this new technology from Bühler Group’s product manager, Alfredo Avendaño.

Katie Woodward: How did the partnership between the Bühler Group and Grupo Elayo come about?

Alfredo Avendaño: The partnership started when Grupo Elayo realised that their existing optical sorting technology wasn’t effective enough in the arduous task of separating the seeds from the stone olive pits.

Grupo Elayo contacted the Bühler Group, hoping their technology would be an effective solution. Fortunately, expectations have been fully met and today, Grupo Elayo is the only company in the world capable of extracting olive seeds successfully.

KW: Why did Grupo Elayo decide to try and extract olive seeds? Who came up with the idea?

AA: Jose Maria Olmo, a mechanical engineer and business economist, with 33 years’ experience in the olive sector, decided to investigate new applications and possible uses for the apparently useless olive stone.

Until then the olive pit and seed inside were discarded as waste, but Jose Maria’s investments in research, development and investigation received positive results and the company started to work on developing new products based on the seeds – consumed raw, roasted as a snack, or used in energy bars or cookies.

KW: Can you tell us more about olive seeds? What nutritional and health benefits do they have?

AA: Olive seeds have been found to contain impressive antioxidant and polyphenol qualities, with an additionally high level of dietary fibre, particularly beneficial for the cardiovascular and muscular system.

A highly concentrated oil can be extracted from the seeds within the olive stone, which offers greater health benefits than conventional olive oil. Olive seed oil is characterised by its high linoleic acid content (polyunsaturated fatty acid omega-6), terpenic acid (maslinic and oleanolic), sterols and polyphenol.

Compared to a standard ‘virgin extra’ olive oil, these components are quadrupled. These bioactive compounds have beneficial effects on health, as antioxidants, anti-inflammatories, cardioprotective agent and anti-tumour, among others, providing value for food, cosmetics or pharmaceutical uses.

KW: What’s the difference between olive seeds and stones?

AA: The olive stone, also known as the olive pit, is the part of the olive that protects the seed until germination. The olive seed is contained within the stone.

KW: How does the optical sorting technology work?

AA: Firstly, the pits are broken and conveyed to the SORTEX optical sorter. Its double-sided cameras detect the differences between seeds, pits and seeds with embedded fragments.

The ejectors accurately target and fire compressed air at all of the pieces that have been identified by the image processing system as defects.

KW: Can you explain the entire process from start to finish?

AA: The process consists of three stages. After the stones are broken, the mix of stone fragments and seeds is conveyed into the first chute of the sorting machine, where the InGaAs cameras aid the separation of stones from seeds. This constitutes almost 90% of the material.

The remainder – about 10% – then undergoes another sort on the second chute, to ensure that only flawless seeds, without any pieces of stone, are sent on for further processing. The third chute re-sorts the rejected material, to recover and seeds still attached to the stone, so they can be sent back to the cracking machine and re-sorted, to minimise wastage of the valuable seeds.

KW: How is the technology able to distinguish between seeds and stones?

AA: Bühler London’s optical sorting technology is equipped with enhanced indium gallium arsenide (InGaAs) cameras. InGaAs cameras are based on semiconductor materials and operate in the short-wavelength infrared range (SWIR). They detect the most subtle differences in colour, which are not visible to the human eye.

Optical sorting technology ensures efficient detection and removal of defective seed and foreign materials, maximising the yield of safe product, for the next state of the oilseed process. An added benefit of the sorting process is the high throughput rate of around 700kg of raw material per hour.

KW: How much waste is there from the process? Can the waste be used in other applications?

AA: Bühler’s sorting solution produces a remarkable yield, as only 1% of the good seeds are lost. Grupo Elayo makes the most of the olive pit, and they have even thought up a way of using the olive stones after the extraction of the seeds, to produce biomass for heating systems, fireplaces and barbecues.

The hulls can also be ground into a powder, which is ideal for use in cosmetic creams, because of its exfoliating effect. Moreover, it can also be used to make robust and durable chipboard.

KW: What are the company’s plans for the future?

AA: Since the foundation of the company, Grupo Elayo have made constant improvements, both in their facilities and the machinery they use in their processes. They continue to investigate ways to: degrease the seeds, improving the yield of oil extraction and achieving a fat-free flour for use as a food ingredient; separate different seeds by their size, so that they can sell them in the edible seed market.

As one of the few companies in the world with the technology to make ‘caviar’ spheres from the olive oil, they want to diversify their business into the gourmet market niches, where they can innovate and develop new applications for the caviar. They are currently producing premium-quality caviar from oil, vinegar, white wine and truffle.