Search Results (7)

Virgin avocado oil (VAO), treasured for its nutritional and sensory properties, is susceptible to oxidation. To improve its oxidative stability, the feasibility of enrichment with antioxidants from avocado or olive-processing by-products via ultrasound-assisted maceration was explored. Dried, milled avocado (AL), olive leaves (OL), or olive pomace (OP) were ultrasound-macerated with laboratory-extracted VAO at 5, 10, and 20% w/w levels. Induction-period (IP) values, determined via Rancimat (110 °C, 20 L/h), increased by 1.1–1.6-fold. Maceration with AL and OL added pigments (β-carotene, lutein, α-chlorophyll, and α-pheophytin) but only AL significantly boosted α-tocopherol levels (up to 3.7-fold). Extraction of major polar phenols (chlorogenic acid, oleuropein, and hydroxytyrosol) was poor (<42 mg/kg oil). Oleanolic and maslinic acids, from OL and OP, reached up to 650 and 260 mg/kg. The IP values correlated (r = 0.796, p = 0.002) only with total polar phenol content. Maceration with OP resulted in superior antioxidant activity, extending the predicted shelf-life from 14 to 22.3 months, reaching that of a hydroxytyrosol-rich extra-virgin olive oil (24.9 months). GC-MS revealed the dominance of volatile acids in OL- and OP-VAOs, and estragole in AL-VAO highlighting some organoleptic and safety challenges to be considered, particularly when aiming to exploit these materials for the enhancement of the oxidative stability of VAOs to sustain its production. Full article

The mitigation of damaged hair conditions involves the application and penetration of substances to stabilize broken bond sites, restore lipids and proteins, reinstate hydrophobicity, and recover hair mechanical properties. Vegetable oils, in general, exhibit a list of advantageous characteristics much desired by consumers, given the associated benefits for hair fibers. While coconut oil is highly popular in the hair care market and extensively studied for its ability to diffuse through the hair cortex, the effects of avocado and argan oil on the internal structure of hair and their potential benefits remain underexplored. Tensile and fatigue tests, as well as Raman spectroscopy, were carried out to investigate the interaction of these three oils with virgin and bleached Caucasian hair. The oils were applied in sufficient amounts directly to hair tresses and maintained for 24 h at 25 °C. Our results show that the three oils successfully diffused and interacted with the cortical region of the hairs. Their impact on hair mechanical properties depends on the level of damage and humidity conditions. In virgin hair, coconut and avocado oil reinforce the hydrophobic barrier of the cellular membrane complex, preventing water from causing intense perturbation of the mechanical properties, leading to increased stiffness and break stress. Meanwhile, due to the high degree of unsaturation of its fatty acid chains, argan oil increases water absorption, resulting in losses in hair resistance. When bleached, the hydrophilicity of the hair fiber increases, determining more affinity for argan oil. Consequently, the affinity with water is also elevated, causing increased fragility to mechanical stress. The analyzed vegetable oils are not always beneficial for hair care. Their specific chemical characteristics and hair conditions will influence the final results and should be taken into consideration in hair care product development. Full article

Extra virgin olive oil (EVOO) and avocado oil (AVO) are recognized for their unique sensory characteristics and bioactive compounds. Declared blends with other vegetable oils are legal, but undeclared mixing is a common type of fraud that can affect product quality and commercialization. In this sense, this study explored strategies to mitigate the influence of lighting in order to make digital image colorimetry (DIC) using a smartphone more robust and reliable for predicting the soybean oil content in EVOO and AVO blends. Calibration models were obtained by multiple linear regression using the images’ RGB values. Corrections based on illuminance and white reference were evaluated to mitigate the lightness effect and improve the method’s robustness and generalization capability. Lastly, the prediction of the built model from data obtained using a distinct smartphone was assessed. The results showed models with good predictive capacities, R² > 0.9. Generally, models solely based on GB values showed better predictive performances. The illuminance corrections and blank subtraction improved the predictions of EVOO and AVO samples, respectively, for image acquisition from distinct smartphones and lighting conditions as evaluated by external validation. It was concluded that adequate data preprocessing enables DIC using a smartphone to be a reliable method for analyzing oil blends, minimizing the effects of variability in lighting and imaging conditions and making it a potential technique for oil quality assurance. Full article

The potential of endogenous n-alkane profiling for the assessment of extra virgin olive oils (EVOO) adulteration (blends with cheaper vegetable oils) has been studied by relatively few authors. Analytical methods used for this purpose often involve tedious and solvent-intensive sample preparation prior to analytical determination, making them unattractive. A rapid and solvent-sparing offline solid phase extraction (SPE) gas chromatography (GC) flame ionization detection (FID) method for the determination of endogenous n-alkanes in vegetable oils was, therefore, optimized and validated. The optimized method demonstrated good performance characteristics in terms of linearity (R² > 0.999), recovery (on average 94%), and repeatability (residual standard deviation, RSD < 11.9%). The results were comparable to those obtained with online high-performance liquid chromatography (HPLC)-GC- FID ( RSD < 5.1%). As an example of an application to prove the potentiality of endogenous n-alkanes in revealing frauds, the data set obtained from 16 EVOO, 9 avocado oils (AVO), and 13 sunflower oils (SFO), purchased from the market, was subjected to statistical analysis and principal component analysis. Two powerful indices, namely (n-C₂₉ + n-C₃₁)/(n-C₂₅ + n-C₂₆) and n-C₂₉/n-C₂₅, were found to reveal the addition of 2% SFO in EVOO and 5% AVO in EVOO, respectively. Further studies are needed to confirm the validity of these promising indices. Full article

Soybean oil is the second most exported oil from the United States and South America, and is widely marketed as a cooking oil product containing numerous health benefits for human consumers. However, culinary oils with high polyunsaturated fatty acid (PUFA) contents, are known to produce high quantities of lipid oxidation products (LOPs), including toxic aldehydes upon exposure to high-temperature frying episodes. Previous studies have demonstrated causal links between aldehyde ingestion and inhalation with deleterious health perturbations, including mutagenic and carcinogenic effects, along with cardiovascular and teratogenic actions. In this study, aldehydic LOPs were detected and quantified in commercially available samples of soybean, avocado, corn and extra-virgin olive oil products before and after their exposure to laboratory-simulated laboratory frying episodes (LSSFEs) using high-resolution 1H nuclear magnetic resonance (NMR) analysis. Results acquired demonstrated that PUFA-rich soybean and corn oils gave rise to the highest concentrations of oil aldehydes from the thermo-oxidation of unsaturated fatty acids, whereas monounsaturated fatty acid (MUFA)-laden avocado and olive oils were much more resistant to this peroxidation process, as expected. Multivariate chemometrics analyses provided evidence that an orthogonal component pattern of aldehydic LOPs featuring low-molecular-mass n-alkanals such as propanal, and 4-oxo-alkanals, arises from thermo-oxidation of the ω-3 fatty acid (FA) linolenic acid (present in soybean oils at levels of ca. 7% (w/w)), was able to at least partially distinguish this oil from corresponding samples of thermally-stressed corn oil. Despite having a similar total PUFA level, corn oil has only a negligible ω-3 FA content, and therefore generated significantly lower levels of these two aldehyde classes. In view of the adverse health effects associated with dietary LOP ingestion, alternative methodologies for the incorporation of soybean oils within high-temperature frying practices are proposed. Full article

Avocado virgin oil (AVO) was used during eggplant deep-frying, boil, and boil in a water-oil mixture (W/O). There were measured the contents of moisture, dry matter, fat, total (TPC) and ten individual phenols, antioxidant activity (ABTS and DPPH), and total sterols; as well as the profiles of eight fatty acids and fourteen sterols/stanols. The values of raw and processed foods were compared and studied with multivariate analysis. The antioxidant capacity of AVO lowered after deep frying but augmented in eggplant and water after all treatments. The TPC was steady in AVO and raised in fried eggplant. Thermal treatments added to the initial profiles of the AVO, eggplant and water, nine, eight, and four phenols, respectively. Percentages of the main fatty acids (oleic, palmitic and linoleic), and sterols (β-sitosterol, campesterol, and Δ5-avenasterol), remained unchanged between the raw and treated AVO; and the lipidic fractions from processed eggplant. Cooking leads to the movement of hydrophilic and lipophilic functional compounds between AVO, eggplant and water. Migration of sterols and unsaturated fatty acids from AVO to eggplant during deep frying and W/O boiling improved the functional properties of eggplant by adding the high biological value lipophilic fraction to the naturally occurring polyphenols. Full article

A comprehensive data collection of authentic “specialty” or “gourmet” oils, namely cold-pressed industrial virgin oils, was performed. Eight different botanical species, i.e., Almond, Apricot, Avocado, Hazelnut, Mosqueta rose, Rosehip, Sunflower, and Walnut oils were studied plus Olive oil as the gold standard of cold-pressed virgin oils. Two different analytical approaches are proposed to rapidly verify the botanical species of the oil-based raw material. The first approach is based on a multivariate statistical analysis of conventional analytical data, namely their fatty acid composition. These data have been re-elaborated in a multivariate way by Principal Component Analysis (PCA) and classification methods. The second approach proposes a fast and non-destructive spectrophotometric analysis to determine the color of these oils to discriminate among different species. In this regard, the raw diffuse reflectance spectra (380–780 nm) obtained by a UV-Vis spectrophotometer with an integrating sphere was considered and elaborated by chemometrics. This information was compared with the results obtained by the most common approach based on the CIELab parameters. A data fusion of chromatographic and spectral data was also investigated. Either fatty acid composition or color of these oils demonstrated to be two promising markers of their botanical authenticity. Full article