Once the olives have been milled, it is essential to classify the oils through chemical and sensory analysis. near infrared (NIR) spectroscopy stands out as a fast, precise and non-destructive method for chemical analysis.
Near-Infrared Spectroscopy (NIR) uses near-infrared light to analyze the chemical and physical properties of samples. It is particularly effective for edible oils and fats, due to its reliability and speed.
Cutting-edge tools
and use in AIPO laboratories
One of the most advanced instruments in this field is the NIRS DS2500 L from FOSS, designed for rapid and precise analysis of vegetable oils, seed oils and other liquid samples. This device measures parameters such as:
• Free fatty acids (FFA).
• Iodine value.
• Colour.
• Other critical parameters for quality.
Thanks to its ease of use and ability to complete an analysis in less than 40 seconds, The NIRS DS2500 L is ideal for process and quality control in industrial environments, offering advanced support, such as FossAssure system, which ensures precision.
FossAssure is an advanced digital support system that provides instrument performance checks, periodic calibrations to maintain accuracy, immediate guidance to operators to resolve any issues, compares new samples to previous data to improve reliability, and provides remote technical support.
In the Italian context, the AIPO Laboratory (Interregional Association of Olive Producers) has adopted this technology to optimize the quality control of oils. Through NIR spectroscopy, AIPO is able to provide rapid, precise and reliable analyses to associated olive growers, ensuring an accurate classification of the oils produced.
How does it work?
La NIR spectroscopy uses a special infrared light composed of different wavelengths ranging from 700 to 2500 nanometers and which is invisible to the human eye. To analyze the samples, the NIR instrument is equipped with a special lamp that emits this light, which passes through the oil sample to be analyzed. The molecules present in the oil, based on their chemical composition, absorb the infrared light retaining only the specific wavelengths associated with them and letting the others pass. This creates a sort of “fingerprint” unique to each sample.
The machine recorded in the form of a graph, called a spectrum, which shows which wavelengths were absorbed and to what extent, each peak and valley representing the absorption of light by specific molecules. This process It allows you to obtain information on the quantity and type of fats, the minor compounds of olive oil such as polyphenols, which affect the flavour, odour and stability of the oil together with the tocopherols.
The result is a spectrum, that is a graph representing how much light was absorbed at different wavelengths which is sent to the machine's processor. The processor analyses the spectrum by comparing it with an internal database of reference spectra, thus allowing the molecules present in the oil to be identified and their quantity to be determined.
In practice, the processor decodes theFingerprint of the oil to provide an accurate analysis of its chemical composition, such as the amount of fatty acids, peroxides, polyphenols and other key components.
Parameters analyzed with the NIR method
Thanks to NIR spectroscopy, it is possible to measure several fundamental parameters for olive oil:
• fatty acid composition: the amount and type of fat present;
• iodine number (iv): indicator of the degree of unsaturation of fats;
• free fatty acids (ffa): measure of non-esterified fatty acids, relevant for assessing freshness;
• trans fatty acids (TFA): fats considered harmful to health;
• anisidine value (anv): detects aldehydes and ketones, indicators of deterioration;
• peroxides: indicate the onset of rancidity;
• k232 and k270: evaluate the oxidation and quality of the oil;
• delta k: difference between k232 and k270, useful for oil stability;
• alkyl esters: components that can alter the flavour;
• waxes: relevant for stability and consistency;
• phenolic composition: contribution to antioxidant properties.
Advantages of the NIR method
The NIR method offers many advantages such as the speed of a complete analysis, which takes less than a minute, then does not alter the sample and does not use dangerous chemicals, measures several parameters simultaneously, providing a complete overview of the quality. The results with the NIR method are precise and repeatable, essential for quality control.
La NIR spectroscopy is widely used in the food industry for quality control of olive, frying and vegetable oils, as well as in scientific research for the study of oil properties and development of new analytical methods. This method is very efficient in the control of agro-industrial processes for real-time monitoring of production.
Conclusion
NIR spectroscopy is a modern and effective technology for analyzing olive oil. Thanks to its precision, speed and ease of use, it is an essential tool to ensure quality and compliance with the highest industry standards.
