Scientists from Universitat Rovira i Virgili (URV) have pioneered a novel technique. It is able to detect rancid hazelnuts without opening their shells. This innovation lies within a broader research project aimed at developing the hazelnut sector in Catalonia. It has a sharp focus on the Tarragona region, home to the majority of the cooperatives.
The hazelnut industry, though very much eclipsed by almonds, is second in yearly output between the two locations. About 90 cooperatives in Catalonia feed into this market, making a combined overall revenue of more than 75 million euros. Hazelnuts are very prone to oxidation, which causes spoilage. What the research team found was that the rate at which this oxidation occurs can significantly accelerate when nuts are poorly packaged.
To develop their approach, the researchers first soaked hazelnuts for 78 days in different solutions. Based on their results, vacuum packaging was determined to be the best way to preserve nuts. Conversely, exposure to light completely destroyed the stability of the product.
“We were able to prove that the vacuum packaging process was the most effective and that exposure to light significantly affects the stability of the product,” – Jokin Ezenarro, a researcher at URV’s Department of Analytical and Organic Chemistry.
The technology uses an in-line spectrophotometer to measure the composition of hazelnuts based on how light interacts with them. Ezenarro continued, “This device is a spectrophotometer. It shines a beam of light on every single point and shows you what the sample is made of, depending on how it interacts with that light.” Their approach illustrates a simple truth—that all organic molecules absorb infrared light, although different molecules will absorb at different frequencies depending on their chemical structure.
Similar systems are being developed to tell the difference between varieties of almonds. They can additionally detect plastics in recycling streams. Catalonia is proving to be a significant power in the sector, especially in its south. This boom underscores just how export-oriented the nut industry has become.
This new technology has tremendous potential, but most of the industry lacks access to it. The high costs of the necessary instruments, usually well above 50,000 euros, are still preventing them from accessing it. Ezenarro is optimistic about the future: “These new techniques are greener. They do not need reagents and do not require sample preparation. In fact, with this method, the measuring instrument does not even need to come into contact with the sample.
“The hyperspectral camera is here to stay,” – Jokin Ezenarro.