Recent Advances in Analytical Methods for the Detection of Olive Oil Oxidation Status during Storage along with Chemometrics, Authenticity and Fraud Studies

A novel method for determination of peroxide value and acid value of extra-virgin olive oil based on fluorescence internal filtering effect correction

Peroxide value (PV) and acid value (AV) are widely used indicators for evaluating oxidation degree of olive oils. Fluorescence spectroscopy has been extensively studied on the detection of oil oxidation, however, the detection accuracy is limited due to internal filtering effect (IFE). Due to the primary and secondary IFE, at least two wavelengths of absorption information are required. Least squares support vector regression (LSSVR) models for PV and AV were established based on two absorption coefficients (μa) at 375 nm and emission wavelength and one fluorescence intensity at corresponding wavelength. The regression results proved that the model based on 375 and 475 nm could reach the best performance, with the highest correlation coefficient for prediction (rp) of 0.889 and 0.960 for PV and AV respectively. Finally, the explicit formulations for PV and AV were determined by nonlinear least squares fitting, and the rp could reach above 0.94 for two indicators.

A targeted foodomic approach to assess differences in extra virgin olive oils: Effects of storage, agronomic and technological factors

Extra virgin olive oil (EVOO) quality and composition are mainly affected by genetics, agronomic and technological parameters, undergoing further modifications during storage. In this work, a chemometric approach was applied to study the impact of olive maturity, malaxation time/temperature, and oil storage on the quality and compositional parameters of Arbequina EVOO (basic quality indices, volatile and sensory profiles, contents in phenolic compounds, squalene, vitamin E and fatty acids). Storage emerged as the most influential factor, followed by olive maturity and malaxation temperature, while malaxation time had almost no effect. Storage at room temperature had a significant impact on the phenolic profile and quality parameters, mainly the peroxide value and K270. The determination of K270, an indicator of secondary oxidation products, was relevant to analyze the effect of storage conditions. Volatile compounds and fatty acids were good markers of ripeness, and the volatile profile was highly affected by malaxation temperature.

Rapid analysis technologies with chemometrics for food authenticity field: A review

In recent years, the problem of food adulteration has become increasingly rampant, seriously hindering the development of food production, consumption, and management. The common analytical methods used to determine food authenticity present challenges, such as complicated analysis processes and time-consuming procedures, necessitating the development of rapid, efficient analysis technology for food authentication. Spectroscopic techniques, ambient ionization mass spectrometry (AIMS), electronic sensors, and DNA-based technology have gradually been applied for food authentication due to advantages such as rapid analysis and simple operation. This paper summarizes the current research on rapid food authenticity analysis technology from three perspectives, including breeds or species determination, quality fraud detection, and geographical origin identification, and introduces chemometrics method adapted to rapid analysis techniques. It aims to promote the development of rapid analysis technology in the food authenticity field.

Gas chromatography ion mobility spectroscopy: A rapid and effective tool for monitoring oil oxidation

Oil autoxidation is an early process of food deterioration, monitoring oil oxidation is therefore of great significance to ensure food quality and safety. In this study, a detection method of the primary and secondary oxidative products was developed by gas chromatography ion mobility spectrometry (GC-IMS).The secondary oxidative products was analyzed by GC-IMS. Then, the relationships between peroxide values and the contents of secondary oxidative products were investigated by constructing a prediction model of peroxide value of rapeseed oil with the help of secondary oxidative products and chemometrics. The coefficient of determination Q2 of the model validation set is 0.96, and the RMSECV is 0.1570 g/100 g. These validation results indicated that secondary oxidative products could also reflect the content of the primary oxidative products. Moreover, 10 characteristic markers related to oxidative rancidity were identified for monitoring edible oil rancidity and oxidative stability.

Enzymatic Modification of Pomace Olive Oil with Natural Antioxidants: Effect on Oxidative Stability

Enzymatic lipophilization has been proposed as a cost-effective strategy to produce new liposoluble antioxidant compounds. In this study, modified oils rich in structured phenolipids were prepared via one-pot enzymatic acylation of hydroxytyrosol (HTYR), vanillyl alcohol (VA) and homovanillyl alcohol (HVA) with pomace olive oil (POO) in solvent-free conditions using immobilized lipase on biogenic nanoparticles. The effect of temperature (30-70 °C) and enzyme concentration (0.1-1%, w/w) on the efficiency of the bioprocess as well as the reusability of the nanobiocatalyst were thoroughly investigated. The modified oils exhibited increased antioxidant activity compared to the control oil according to DPPH and CUPRAC assays (p < 0.05). The oxidative stability of pomace olive oil was also significantly enhanced after modification, as depicted by the K₂₃₂ values and TBARS contents under accelerated oxidation at 60 °C (p < 0.05). Moreover, a fortified mayonnaise containing modified oil with HTYR was prepared that was noticeably stable compared to the control mayonnaise at 28 °C for 5 months (p < 0.05). Enzymatically modified oils have great potential for application in the nutraceutical and food industry, encouraging the exploitation of immobilized lipases as effective and green catalytic tools.

Classification and Antioxidant Activity Evaluation of Edible Oils by Using Nanomaterial-Based Electrochemical Sensors

The classification of olive oils and the authentication of their biological or geographic origin are important issues for public health and for the olive oil market and related industries. The development of techniques for olive oil classification that are fast, easy to use, and suitable for online, in situ and remote operation is of high interest. In this study, the possibility of discriminating and classifying vegetable oils according to different criteria related to biological or geographical origin was assessed using cyclic voltammograms (CVs) as input data, obtained with electrochemical sensors based on carbonaceous nanomaterials and gold nanoparticles. In this context, 44 vegetable oil samples of different categories were analyzed and the capacity of the sensor array coupled with multivariate analysis was evaluated. The characteristics highlighted in voltammograms are related to the redox properties of the electroactive compounds, mainly phenolics, existing in the oils. Moreover, the antioxidant activity of the oils' hydrophilic fraction was also estimated by conventional spectrophotometric methods (1,1-diphenyl-2-picrylhydrazyl (DPPH) and galvinoxyl) and correlated with the voltammetric responses of the sensors. The percentage of DPPH and galvinoxyl inhibition was accurately predicted from the voltammetric data, with a correlation coefficients greater than 0.97 both in calibration and in validation. The results indicate that this method allows for a clear discrimination of oils from different biological or geographic origins.