Quality Control from Olive to Oil
Why FT-NIR Spectroscopy?
The quality of extra virgin olive oil vastly depends on the olive itself, as it is the only cooking oil that is made by cold-pressing the fruit without the use of chemicals and industrial refining. This makes it expensive and thus prone for adulteration.
FT-NIR spectroscopy offers a valuable tool for monitoring the complete production process from the olives to the extraction process and the finished olive oil with only one analyzer.
FT-NIR spectroscopy can universally be applied for the compositional analysis of olives, pomace and olive oil independent from the type of sample:
- Analyze Olive Leaves to assess the nutritional status of the cultivars
- Test Incoming Olives to guarantee a fair payment scheme
- Monitor Pomace and Orujo to control and optimize your processes
- Assess Olive Oil Quality to classify the quality grade
Fingerprinting your sample
FT-NIR spectroscopy simply measures the interaction of near-infrared light with the sample at all the different wavelengths - just like a chemical fingerprint. The resulting NIR spectrum shows absorption bands of mainly C-H, N-H and O-H groups, making NIR spectroscopy first choice for the analysis of organic materials like oilseeds and edible oils.
Saving time and Money
The FT-NIR technology offers a lot of advantages over classical wet-chemical and chromatographic analyses. It is quick, cost-effective and safe, since no hazardous chemicals are used. Our FT-NIR spectrometers use modern, high quality optical components with a long lifetime. Adding the low energy consumption results in minimal running costs.
Being able to measure more samples in a shorter time will help you to constantly assess the quality - from checking the incoming olives up to quality testing the finished oils.
The best system for your needs
Bruker Optics FT-NIR analyzers for quality control in the lab or production area are easy to use, rugged and reliable. Based on the same FT-NIR platform, users can choose the right analyzer for the job without having to compromise on precision and accuracy, ensuring data integrity and transferability today and in the future. Bruker Optics’ portfolio ranges from small footprint, touch screen operated analyzers to fully automated in-process systems for closed loop control.
Olive Testing
The vast majority of olives grown all over the world are used for the manufacture of olive oil. The value of an olive crop is mostly determined by the oil content. Depending on the time of the harvest and the olive variety, the olive oil content may vary between 10 – 30%. To determine the exact oil content is essential for the farmers and the industry alike to estimate the value of a harvest.
Traditional wet chemical methods, e.g. Soxhlet analysis become increasingly unacceptable in the laboratory since they require large amount of solvents, creating health and safety risks as well as environmental issues. Furthermore, the measurement results are often operator dependent and the procedure is slow.
With FT-NIR, the ground olives are analyzed in less than a minute, using no harmful chemicals or solvents. Simply put the sample into a petri dish and place it on the instrument. With only one measurement, not only the fat and moisture of the olives can be measured, but also the acidity can be assessed at the point of delivery, a criterion for good manufacturing practice during the harvest and the storage of the olives.
Bruker Optics developed ready-to-use calibrations for a quick and efficient start with FT-NIR technology.
Production Control
Looking at the complete process of olive oil production, many parameters have to be taken into account to optimize the oil yield.
An optimal crushing of the olives is essential to break the plant tissues and release the oil from the mesocarp cells. In the following step, the olive paste is treated in the mixer (malaxer) to form larger droplets of oil. Here the correct kneading time and temperature is essential, as well as selecting the right auxiliary materials like talc or enzymes. For the extraction of the oil, choosing the correct speed, paste/water ratio and load capacity of the centrifugal decanter will also improve the yield.
To determine the maximum oil extraction yield and optimized operation of the olive production systems, a simultaneous variation of the parameters must be examined. FT-NIR is a simple and fast analysis with no sample preparation which enables the operator to test the olive pomace (alperujo) for residual oil content, which should be typically around 3% or lower.
This way FT-NIR helps to find problems along the production chain and to quickly react on varying process conditions. By keeping the oil content of the press residues to a low level, the production site can run more cost-effectively.
Olive Oil Quality
QC of Olive Oils
An acidity value below 0.8% is the main criterion for the classification of the olive oil as “extra virgin”. Other quality parameters include the peroxide value, an indication for the rancidity of the oil as well as as well as the K-values (UV absorption) and many others.
Unlike wine, the quality of olive oil does not improve with age and sooner or later it will become rancid. The amount of 1,2-diglycerides as well as the pyropheophytin content in the oil reveals if a an olive oil was stored for too long or even adulterated with refined (olive) oils to obtain lower acidity values.
All these critical parameters can be tested with a 30 second FT-NIR measurement, enabling a thorough quality control along the production chain of the oil.
Testing on adulteration
A common problem not only for the olive oil industry is the adulteration of high priced olive oil with cheaper seed oils such as sunflower or hazelnut oil. Today’s public awareness of the health benefit of olive oil makes the adulteration economically attractive. Chemically, most oils are very similar and a blend is difficult to identify with common quick tests like measuring refractive index.
However the different oils vary in their fatty acid profile and FT-NIR spectroscopy can offer a valuable tool for determining other types of oil in olive oil down to a low percentage range. Another issue regarding adulteration is to determine the geographic origin of the oils for certification purposes (RDO labeling). Combined with other techniques, FT-NIR can deliver valuable supplementary information.
Leaves and Soil
Olive Leaf Analysis
Compared to other fruit trees, olive trees do not require a large amount of fertilization. Very fertile conditions might be very counterproductive, since it reinforces vegetative growth, but inhibits adequate bloom and fruit set. The correct balance of nutrients is important for optimum harvests.
This is why testing the olive leaves for nitrogen (N) and phosphorus (P), as well as for potassium (K), calcium (Ca) and magnesium (Mg) helps to avoid deficiencies as well as excessive nutrient levels and to maintain the health of the olive grove. Sampling the olive leaves over a number of seasons can help to build up a comprehensive record regarding the fertilization status of the olive grove.
To analyze the leave tissue by FT-NIR spectroscopy for nutrients, a representative amount of leaves is collected and then dried and finely grinded. The analysis is carried out in less than a minute giving you an overview of the most important nutrients.
Soil Analysis
The analysis of soil provides complementary information to the leaf analysis. Here, FT-NIR spectroscopy offers a fast and cost effective tool for analyzing total carbon and total nitrogen in the soil, two parameters that help to better understand and manage the effects of fertilization.
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