Design and in-house validation of a portable system for the determination of free acidity in virgin olive oil

Abstract

Nutritional and healthy values are well known properties of virgin olive oil (VOO). The product quality, in terms of belonging to a specific quality grade (extra virgin, virgin, lampante), is defined by a set of chemical-physical and sensory measurements. According to the official regulation of the European Union (EU Reg. 1348/2013) the free acidity is the first parameter that has to be determined by analysts; it gives information about the quality of the olives used to produce the VOO as well as the hydrolytic state of VOO just produced and stored. The official procedure is based on an acid-base titration that needs to be carried out in a chemical laboratory. In this paper a portable battery-operated electronic system to measure olive oil free acidity is presented: the system can be used for quick "in situ" tests in a production environment (olive oil mills or packaging centers) by people without particular training. The working principles of the system is based on the creation of an emulsion between oil and a hydroalcoholic solution: the free acidity is estimated on the value of the emulsion electrical conductance. This new system has been calibrated and in-house validated showing good results in terms of limit of detection and quantification, precision and accuracy, beyond a good correlation with free acidity data obtained applying the official method (R 2 adj = 0.97).

Effect of Storage Conditions on the Quality of Arbequina Extra Virgin Olive Oil and the Impact on the Composition of Flavor-Related Compounds (Phenols and Volatiles)

“…The %FFA of samples stored at C4 (30 ± 2 • C) and C5 (40 ± 2 • C) conditions, both in darkness, increased beginning after 6 months, reaching a statistically higher value (p < 0.05) of 0.32 % of oleic acid in the C5 condition compared to all other storage conditions. The increase in %FFA at higher temperatures might be due to higher hydrolytic activity of lipase enzymes on triacylglycerols that remain in the oil after extraction [5], which could be further influenced by the moisture levels in the oil [30]. In all conditions, the %FFA did not reach 0.8%, the maximum allowed by IOC for EVOO category [2], and were lower than those reported by Ayton et al [5] when olive oil was stored at 37 • C without oxygen in darkness.…”

Chemical Analysis of Minor Bioactive Components and Cannabidiolic Acid in Commercial Hemp Seed Oil

“…Although the quality parameters could not be compared with extra virgin oil [59], and the high acidity could impact on sensory characteristics of oil, such as flavor, the collateral characteristics make it still a very valuable oil. These oil benefits encourage the chemical industries versus the optimization of extraction process in order to accomplish the quality of the product [39].…”

Handheld Near‐Infrared Spectroscopy for Distinction of Extra Virgin Olive Oil from Other Olive Oil Grades Substantiated by Compositional Data

“…Handheld NIRS have been applied in lipid analysis for quantitation of vegetable oil in diesel, for quantitation of trans fat in edible oils, for purity determination of copaiba oils, and for detection of lard adulteration in palm oil . Furthermore, specific olive (oil) applications concern the on‐line evaluation of the oil content of olives during olive processing and the measurement of olive oil acidity . However, the application of handheld NIRS for distinction of EVOO from lower grade counterparts has not been done before.…”