Chromatographic analysis of minor constituents in vegetable oils

Green solvent 2-methyltetrahydrofuran (2-MeTHF) improves recovery of bioactive molecules from oilseeds and prevents lipid peroxidation in oils

The study compared the effects of hexane and 2-methyltetrahydrofuran (MeTHF) on oil yield, stability and bioactive compounds in fig, black cumin and rosehip oils. MeTHF increased oil yield in fig (11.7 %), black cumin (28.3 %) and rosehip (13.2 %). Solvent type did not change fatty acid and tocopherol composition and 18 fatty acids were identified. MeTHF increased number of phenolic compounds from 9 to 16 and amount of total tocopherol, phenolics, chlorophylls and carotenoids in oils. The antioxidant activity of oils was measured by CUPRAC and DPPH assays and MeTHF extracted oils had significantly higher antioxidant capacity. Oxidative stability test revealed that hexane-extracted oils peroxide value (PV) increased dramatically in fig (182.7 %) and rosehip (221.1 %) oils, while PV of MeTHF extracted oils was not significant in fig and rosehip oils. Black cumin oil was stable for both solvents. Results show that MeTHF is more efficient for obtaining oils with bioactive molecules to improve stability and quality.

The Journey of Artificial Intelligence in Food Authentication: From Label Attribute to Fraud Detection

Artificial intelligence (AI) tends to be extensively used to develop reliable, fast, and inexpensive tools for authenticity control. Initially applied for food differentiation as an alternative to statistical methods, AI tools opened a new dimension in adulteration identification based on images. This comprehensive review aims to emphasize the main pillars for applying AI for food authentication: (i) food classification; (ii) detection of subtle adulteration through extraneous ingredient addition/substitution; and (iii) fast recognition tools development based on image processing. As opposed to statistical methods, AI proves to be a valuable tool for quality and authenticity assessment, especially for input data represented by digital images. This review highlights the successful application of AI on data obtained through laborious, highly sensitive analytical methods up to very easy-to-record data by non-experimented personnel (i.e., image acquisition). The enhanced capability of AI can substitute the need for expensive and time-consuming analysis to generate the same conclusion.

Extraction of Oil from Allium iranicum Seed and Evaluation of Its Composition and Quality Characteristics

The Allium plant genus has many species, among which Allium iranicum (AI) from the family Amaryllidaceae is endemic to Iran. There is no report on the oil composition of AI seeds. In this study, oil from AI seeds was extracted by a solvent and its composition and quality characteristics were determined. The yield of seed oil was 14.3%. The most predominant unsaturated fatty acid was linoleic acid (64.4%), followed by oleic acid (16.9%), and the main saturated fatty acids were palmitic acid (13.6%) followed by stearic acid (2.8%). Beta-sitosterol (50.7%), campestrol (15.7%), and delta5-avenasterol (8.2%) were the most dominant phytosterols in extracted AI oil. The most dominant tocopherol was α-tocopherol (1188 ppm) along with low amounts of δ- and γ-tocopherols. The obtained results showed that the oil extracted from seeds of AI can be a valuable by-product of this plant with suitable nutritional indices and can be used as a new source of vegetable oil. Further research is required to reveal its potential pharmaceutical and food applications.

High temperature perturbs physicochemical parameters and fatty acids composition of safflower (Carthamus tinctorius L.)

Future climates will realise increasingly frequent extreme weather events, which will impact on the quantum and quality of crop production. While effects of extreme heat on crop production have been well studied hitherto, there remains a dearth of knowledge pertaining to the impacts of extreme heat on grain quality. As such, our purpose here was to evaluate the effects of terminal heat stress on the physicochemical properties and composition of seed oil of safflower plants. Using two contemporary cultivars with varying genetic tolerance to heat stress (Faraman and Sofeh), we found that exposure to extreme heat reduced grain yield by 53-57%. Four fatty acids (palmitic, stearic, oleic and linoleic acid) comprised 96-99% of total fatty acid methyl esters; relative composition varied in response to heat stress and other environmental conditions. In the first experimental year (2017-18), saturated fatty acids in Sofeh and Faraman cultivars increased by 69% and 18% respectively, while unsaturated fatty acids decreased by 9% and 4%, respectively. In the second experimental year (2018-19), saturated fatty acids increased by 10% in Sofeh and by less than 1% in Farman, while unsaturated fatty acids in both cultivars were not significantly altered. Physicochemical parameters differed across years and cultivars; exposure to high temperature increased chlorophyll and carotenoid content in Sofeh, but decreased the said parameters in Faraman. In 2017-18, effects of heat stress on thiobarbituric acid were variable, but in 2018-19, thiobarbituric acid increased in both cultivars. In all cases, saponification and iodine content increased in response to heat stress. In sum, the fatty acid profile of safflower exposed to terminal heat stress was less affected compared with oil physicochemical parameters, due to greater temperature sensitivity of the latter.

Physicochemical properties, profile of volatiles, fatty acids, lipids and concomitants from four Kadsura coccinea seed oils

The Kadsura coccinea fruit is a wild fruit that may be eaten and used medicinally. Its seeds are rich in nutrients but are typically thrown away without processing.The physicochemical characterization, volatiles, fatty acids, lipids and concomitants of cold-processed seed oils from four kinds of K. coccinea were evaluated. The average kernel yield and oil yield of K. coccinea seeds were 68.21 % and 30.44 %, respectively. The seed oil contains a moderate level of total phenolics (368.99-503.99 mgGAE/100 g), total flavonoids (95.01-126.18 mg RE/100 g), and β-sitosterol (1498.8-1712.7 mg/kg) with higher iodine value, lower acid value, saponification value and shorter induction time. GC analysis reveals appreciable amounts of linoleic acid (64.91-68.05 %) and squalene in seed oil. GC-MS analysis showed that the major volatile compounds were γ-muurolene (27.25-31.7 %), β-himachalene (19.51-20.37 %) and β-curcumene (15.78-16.78 %). Moreover, 16 terpenoids, 14 phenolics were identified by UPLC-QTOF-MS/MS. These results suggest that K. coccinea seed seems an promising alternative oilseed with biological ingredients for food, cosmetics and pharmaceutical industries.

A Comprehensive Study for Determination of Free Fatty Acids in Selected Biological Materials: A Review

The quality of oil is highly dependent on its free fatty acid (FFA) content, especially due to increased restrictions on renewable fuels. As a result, there has been a growing interest in free fatty acid determination methods over the last few decades. While various standard methods are currently available, such as the American Oil Chemists Society (AOCS), International Union of Pure and Applied Chemistry (IUPAC), and Japan Oil Chemists' Society (JOCS), to obtain accurate results, there is a pressing need to investigate a fast, accurate, feasible, and eco-friendly methodology for determining FFA in biological materials. This is owing to inadequate characteristics of the methods, such as solvent consumption and reproducibility, among others. This study aims to investigate FFA determination methods to identify suitable approaches and introduce a fresh perspective.

Sample preparation of free sterols from vegetable oils by countercurrent chromatography in co-current mode

Countercurrent chromatography (CCC) is a preparative instrumental method where both the mobile and stationary phases are liquids and which are predominantly used for the isolation of natural products. In this study, we widened the scope of CCC by using it as an instrumental method for the direct enrichment of the free sterol fraction from plant oils to which they contribute with ~ 1%. For the enrichment of sterols in a narrow band, we employed the so-called co-current CCC (ccCCC) mode in which both liquid phases of the solvent system (here: n-hexane/ethanol/methanol/water (34:11:12:2, v/v/v/v)) are moved at different flow rates in the same direction. Different from previous applications of ccCCC, the lower and predominant "stationary" phase (LP_s) was pumped twice as fast as the mobile upper phase (UP_m). This novel reversed ccCCC mode improved the performance but also required a higher demand of LP_s compared to UP_m. Therefore, the exact phase composition of UP_m and LP_s was determined by gas chromatography and Karl Fischer titration. This step enabled the direct preparation of LP_s which considerably reduced the waste of solvents. Internal standards (phenyl-substituted fatty acid alkyl esters) were synthesised and utilised to frame the free sterol fraction. This approach allowed a fractionation of free sterols based on the UV signal and compensated run-to-run variations. The reversed ccCCC method was then applied to the sample preparation of five vegetable oils. In addition to free sterols, free tocochromanols (tocopherols, vitamin E) were also eluted in the same fraction as free sterols.

Effect of Refining and Fractionation Processes on Minor Components, Fatty Acids, Antioxidant and Antimicrobial Activities of Shea Butter

Shea butter is becoming increasingly popular in foods, cosmetics and pharmaceutical products. This work aims to study the effect of the refining process on the quality and stability of fractionated and mixed shea butters. Crude shea butter, refined shea stearin, olein and their mixture (1:1 w/w) were analyzed for fatty acids, triacylglycerol composition, peroxide value (PV), free fatty acids (FFA), phenolic (TPC), flavonoid (TFC), unsaponifiable matter (USM), tocopherol and phytosterol content. Additionally, the oxidative stability, radical scavenging activity (RSA), antibacterial and antifungal activities were evaluated. The two main fatty acids in the shea butter samples were stearic and oleic. The refined shea stearin showed lower PV, FFA, USM, TPC, TFC, RSA, tocopherol and sterol content than crude shea butter. A higher EC50 was observed, but antibacterial activity was much lower. The refined olein fraction was characterized by lower PV, FFA and TFC in comparison with crude shea butter, but USM, TPC, RSA, EC50, tocopherol and sterol content was unchanged. The antibacterial activity was higher, but the antifungal activity was lower than those of crude shea butter. When both fractions were mixed, their fatty acid and triacylglycerol composition were similar to those of crude shea butter, but other parameters were different.

Hemp Seed Oil and Oilseed Radish Oil as New Sources of Raw Materials for the Synthesis of Bio-Polyols for Open-Cell Polyurethane Foams

We report on the development of open-cell polyurethane foams based on bio-polyols from vegetable oils: hemp seed oil, oilseed radish oil, rapeseed oil and used rapeseed cooking oil. The crude oils were pressed from seeds and subjected to an optimal solvent-free epoxidation process. Bio-polyols were obtained by a ring-opening reaction using diethylene glycol and tetrafluoroboric acid as catalysts. The resultant foams were analysed in terms of their apparent density, thermal conductivity coefficient, mechanical strength, closed cell content, short-term water absorption and water vapour permeability, while their morphology was examined using scanning electron microscopy. It was found that regardless of the properties of the oils, especially the content of unsaturated bonds, it was possible to obtain bio-polyols with very similar properties. The foams were characterized by apparent densities ranging from 11.2 to 12.1 kg/m3, thermal conductivity of <39 mW/m∙K, open cell contents of >97% and high water vapour permeability.

Spectral and Luminescence Properties of Linseed Oils of Different Prehistory

The spectral and luminescence properties of linseed oils with different background have been studied. High informativity of oil fluorophores (phenols, tocopherols, polyunsaturated fatty acids, vitamins, pigments) as to their native state depending on the influence of various destructive factors: extended storage period of oil (three years), exposure to sunlight for 50 h and contact with temperatures in the range of 60 ºC > t > 46 ºC was registered.It was revealed that: 1. Exposure of linseed oil to sunlight for 50 h and contact with temperatures 60 ºC > t > 46 ºC during the process of oil extraction don't lead to visible changes in the structures of their luminescence spectra and luminescence excitation spectra. 2. Long storage period of oil (> 3 years) leads to: (a) decomposition of phenols, tocopherols, polyunsaturated fatty acids (linoleic, linolenic, arachidonic), vitamins (B₂, E, carotene), accompanied by the appearance of emission bands with maxima λ_max = 350, 370, 390, 425, 440, 470, 520 nm, which are attributed to the products of their oxidation, increase of their luminescence intensity and changes in the structure of the luminescence excitation spectra of fluorophores: phenols, tocopherols, polyunsaturated fatty acids (linoleic, linolenic, arachidonic) and vitamins (B₂, E, carotene); (b) decrease in the intensity of the luminescence bands of phenol, tocopherol, carotene and chlorophyll pigment.

Characterization of Volatile Flavor Compounds in Supercritical Fluid Separated and Identified in Gurum (Citrulluslanatus Var. colocynthoide) Seed Oil Using HSME and GC-MS

In this study, the volatile compound profiles of gurum seed oil were determined using two methods: supercritical CO₂ extraction (SFE) and the screw press process (SPP). For volatile compounds extraction and identification, headspace solid-phase micro-extraction (HS-SPME) and GC-MS were used, respectively. A total number of 56 volatile compounds were revealed and identified in oil extracted by SFE, while only 40 compounds were detected in extracted oil by SPP. Acids, aldehydes, esters, ketones, furans, and other components were present in the highest ratio in oil extracted by SFE. In contrast, alcohols and alkenes were found in the highest proportion in oil extracted by SPP. In this study, it was observed that SFE showed an increase in the amounts of volatile compounds and favorably impacted the aroma of gurum seed oil. The results reveal that different extraction methods significantly impact the volatile components of gurum seed oil, and this study can help evaluate the quality of the oil extracted from gurum seeds.

Development of highly hydrophobic fabric phase sorptive extraction membranes and exploring their applications for the rapid determination of tocopherols in edible oils analyzed by high pressure liquid chromatography-diode array detection

Α novel, green, and facile fabric phase sorptive extraction (FPSE) prior to high pressure liquid chromatography with diode array detection (HPLC-DAD) methodology was developed for the efficient extraction and quantitative determination of tocopherols (α-, sum of (β+γ), and δ-) in edible oils. Among several highly hydrophobic FPSE membranes, sol-gel polycaprolactone-polydimethylsiloxane-polycaprolactone (sol-gel PCAP-PDMS-PCAP) coated polyester FPSE membrane was found as the most efficient in extracting tocopherol homologues from edible oil samples. To maximize the extraction efficiency of FPSE membrane, major parameters of FPSE including the membrane size, sample loading time, the choice of the appropriate elution solvent and the elution solvent volume, desorption time, and the influence of stirring were systematically optimized. The developed FPSE-HPLC-DAD methodology was validated and presented adequately low limits of detection (LODs) and limits of quantification (LOQs) over the ranges 0.05-0.10 μg/g, and 0.17-0.33 μg/g, respectively. The RSD% of the within-day and between-day assays were lower than 1.3, and 11.8, respectively, demonstrating good method precision. The trueness of the method was assessed by means of relative percentage of recovery and ranged between 90.8 and 95.1% for within-day assay, and between 88.7-92.8% for between-day assay. The developed methodology was applied in the analysis of edible oils.

Screening for mineral oil hydrocarbons in vegetable oils by silver ion-planar solid phase extraction

The analysis of mineral oil hydrocarbons in vegetable oils is challenging especially regarding the analysis of mineral oil aromatic hydrocarbons (MOAH) since native terpenes like squalene or β-carotene are usually extracted along with the MOAH fraction and interfere their detection. When applying a recently developed screening method for the analysis of mineral oil saturated hydrocarbons (MOSH) and MOAH in paper and cardboard by planar solid phase extraction (pSPE) to vegetable oils, native terpenes expectably interfered with MOAH analysis. Thus, an adaption of pSPE employing silver ions, named silver ion-planar solid phase extraction (Ag-pSPE), was developed in this study. Impregnation of thin-layers with silver nitrate (AgNO₃) was found to be very successful in retaining squalene and β-carotene. MOAH analysis of vegetable oils after saponification showed good repeatability (relative standard deviation (%RSD) <10%) and recoveries of 73.4-112.4% at a spiking level of 4.5 mg/kg (n = 4). For MOSH analysis, a simple solid phase extraction (SPE) clean-up with aluminum oxide removed native n-alkanes prior to Ag-pSPE. Recoveries for MOSH were 55.3-84.5% with %RSD <11% at a spiking level of 45.5 mg/kg (n = 4). Limits of decision and quantitation were at 7.2 and 22.2 ng/zone for MOSH and 1.1 and 3.4 ng/zone for MOAH, respectively, which corresponded to the recently introduced pSPE method, thus showing that analytes were not affected by the impregnation of HPTLC plates with AgNO₃. The method comparison with LC-GC showed similar results for MOSH, while the amounts for MOAH determined by Ag-pSPE were higher.

Bioactive Molecules of Mandarin Seed Oils Diminish Mycotoxin and the Existence of Fungi

Mandarin is a favorite fruit of the citrus family. Mandarin seeds are considered a source of nontraditional oil obtained from byproduct materials. This investigation aimed to assess the biomolecules of mandarin seeds and evaluated their antimycotic and antimycotoxigenic impact on fungi. Moreover, it evaluated the protective role of mandarin oil against aflatoxin toxicity in cell lines. The two types of extracted oil (fixed and volatile) were ecofriendly. The fatty acid composition, tocopherol, sterols, and carotenoids were determined in the fixed oil, whereas volatiles and phenolics were estimated in the essential oil. A mixture of the two oils was prepared and evaluated for its antimicrobial impact. The reduction effect of this mixture was also investigated to reduce mycotoxin secretion using a simulated experiment. The protective effect of the oil was evaluated using healthy strains of cell lines. Fixed oil was distinguished by the omega fatty acid content (76.24%), lutein was the major carotenoid (504.3 mg/100 g) and it had a high β-sitosterol content (294.6 mg/100 g). Essential oil contained limonene (66.05%), α-pinene (6.82%), β-pinene (4.32%), and γ-terpinene (12.31%) in significant amounts, while gallic acid and catechol were recorded as the dominant phenolics. Evaluation of the oil mix for antimicrobial potency reflected a considerable impact against pathogenic bacteria and toxigenic fungi. By its application to the fungal media, this oil mix possessed a capacity for reducing mycotoxin secretion. The oil mix was also shown to have a low cytotoxic effect against healthy strains of cell lines and had potency in reducing the mortality impact of aflatoxin B₁ applied to cell lines. These results recommend further study to involve this oil in food safety applications.

Co-pyrolysis of food waste and wood bark to produce hydrogen with minimizing pollutant emissions

In this study, the co-pyrolysis of food waste with lignocellulosic biomass (wood bark) in a continuous-flow pyrolysis reactor was considered as an effective strategy for the clean disposal and value-added utilization of the biowaste. To achieve this aim, the effects of major co-pyrolysis parameters such as pyrolysis temperature, the flow rate of the pyrolysis medium (nitrogen (N₂) gas), and the blending ratio of food waste/wood bark on the yields, compositions, and properties of three-phase pyrolytic products (i.e., non-condensable gases, condensable compounds, and char) were investigated. The temperature and the food waste/wood bark ratio were found to affect the pyrolytic product yields, while the N₂ flow rate did not. More non-condensable gases and less char were produced at higher temperatures. For example, as the temperature was increased from 300 °C to 700 °C, the yield of non-condensable gases increased from 6.3 to 17.5 wt%, while the yield of char decreased from 63.6 to 30.6 wt% for the co-pyrolysis of food waste and wood bark at a weight ratio of 1:1. Both the highest yield of hydrogen (H₂) gas and the most significant suppression of the formation of phenolic and polycyclic aromatic hydrocarbon (PAH) compounds were achieved with a combination of food waste and wood bark at a weight ratio of 1:1 at 700 °C. The results suggest that the synergetic effect of food waste and lignocellulosic biomass during co-pyrolysis can be exploited to increase the H₂ yield while limiting the formation of phenolic compounds and PAH derivatives. This study has also proven the effectiveness of co-pyrolysis as a process for the valorization of biowaste that is produced by agriculture, forestry, and the food industry, while reducing the formation of harmful chemicals.

Effects of storage on the oxidative stability of acorn oils extracted from three different Quercus species

BACKGROUND

Acorn fruit and its components and by-products are receiving renewed interest due to their nutritional and phytochemical features. In particular, the oil extracted from acorns is recognized for having high nutritional quality and for being rich in bioactive compounds. Despite the growing interest, few papers are available that consider the evolution of acorn-oil characteristics during storage. Our aim was to investigate the storage-related changes in acorn oils extracted from three Quercus species grown in Algeria (Q. ilex, Q. suber, and Q. coccifera) 180 days after production, with a focus on polar and volatile compounds, not yet investigated. Basic quality parameters, phenolic content, antioxidant activity and induction time were also monitored.

RESULTS

The oxidation markers (peroxide value and UV absorptions) increased during storage, whereas antioxidants decreased. A distinctive volatile profile was observed at the time of production, which underwent changes during storage. Polar compounds increased, whereas induction time decreased. The oil extracted from Quercus suber L. was the most affected by storage time.

CONCLUSION

Floral and fruity volatile compounds detected in the oils' headspace could explain the pleasant flavor of acorn oils reported by other authors. As with other vegetable oils, storage depletes both volatiles and antioxidants and produces oxidation compounds, such as oxidized triacylglycerols. However, the acorn oils that were studied were quite stable under storage in the dark at room temperature for 6 months. © 2020 Society of Chemical Industry.

Relationship between olive oil consumption and ankle-brachial pressure index in a population at high cardiovascular risk

BACKGROUND AND AIMS

The aim of this study was to ascertain the association between the consumption of different categories of edible olive oils (virgin olive oils and olive oil) and olive pomace oil and ankle-brachial pressure index (ABI) in participants in the PREDIMED-Plus study, a trial of lifestyle modification for weight and cardiovascular event reduction in individuals with overweight/obesity harboring the metabolic syndrome.

METHODS

We performed a cross-sectional analysis of the PREDIMED-Plus trial. Consumption of any category of olive oil and olive pomace oil was assessed through a validated food-frequency questionnaire. Multivariable linear regression models were fitted to assess associations between olive oil consumption and ABI. Additionally, ABI ≤1 was considered as the outcome in logistic models with different categories of olive oil and olive pomace oil as exposure.

RESULTS

Among 4330 participants, the highest quintile of total olive oil consumption (sum of all categories of olive oil and olive pomace oil) was associated with higher mean values of ABI (beta coefficient: 0.014, 95% confidence interval [CI]: 0.002, 0.027) (p for trend = 0.010). Logistic models comparing the consumption of different categories of olive oils, olive pomace oil and ABI ≤1 values revealed an inverse association between virgin olive oils consumption and the likelihood of a low ABI (odds ratio [OR] 0.73, 95% CI [0.56, 0.97]), while consumption of olive pomace oil was positively associated with a low ABI (OR 1.22 95% CI [1.00, 1.48]).

CONCLUSIONS

In a Mediterranean population at high cardiovascular risk, total olive oil consumption was associated with a higher mean ABI. These results suggest that olive oil consumption may be beneficial for peripheral artery disease prevention, but longitudinal studies are needed.

Edible Oils Differentiation Based on the Determination of Fatty Acids Profile and Raman Spectroscopy—A Case Study

This study proposes a comparison between two analytical techniques for edible oil classification, namely gas-chromatography equipped with a flame ionization detector (GC-FID), which is an acknowledged technique for fatty acid analysis, and Raman spectroscopy, as a real time noninvasive technique. Due to the complexity of the investigated matrix, we used both methods in connection with chemometrics processing for a quick and valuable evaluation of oils. In addition to this, the possible adulteration of investigated oil varieties (sesame, hemp, walnut, linseed, sea buckthorn) with sunflower oil was also tested. In order to extract the meaningful information from the experimental data set, a supervised chemometric technique, namely linear discriminant analysis (LDA), was applied. Moreover, for possible adulteration detection, an artificial neural network (ANN) was also employed. Based on the results provided by ANN, it was possible to detect the mixture between sea buckthorn and sunflower oil.

Deep eutectic solvent-based liquid-phase microextraction coupled with reversed-phase high-performance liquid chromatography for determination of α-, β-, γ-, and δ-tocopherol in edible oils

For simultaneous analysis of four fat-soluble tocopherols (α-, β-, γ-, and δ-) in edible oils, an efficient and green method using deep eutectic solvent-based liquid-phase microextraction (DES-LPME) coupled with reversed-phase high-performance liquid chromatography (RP-HPLC) was developed. The DESs formed by different quaternary ammonium salts and ethanol were used as the extractants. Tetrabutylammonium chloride (TBAC)-ethanol DES at a molar ratio of 1:2 achieved the best extraction efficiency. Under the optimized conditions, the detection limits were in the range of 2.1-3.0 ng mL^-1. The intra-day and inter-day repeatability were in the ranges of 3.9-5.3% and 4.8-7.1%, respectively, and the recoveries for the real samples varied from 80.7% to 105.4%. The developed method was successfully employed for the determination of all four tocopherol homologues with an RP-HPLC system containing a COSMOSIL π-NAP column in five edible oils collected locally. Graphical abstract.

Comparative metabolomics of Phialemonium curvatum as an omnipotent fungus cultivated on crude palm oil versus glucose

BACKGROUND

Sugars and triglycerides are common carbon sources for microorganisms. Nonetheless, a systematic comparative interpretation of metabolic changes upon vegetable oil or glucose as sole carbon source is still lacking. Selected fungi that can grow in acidic mineral salt media (MSM) with vegetable oil had been identified recently. Hence, this study aimed to investigate the overall metabolite changes of an omnipotent fungus and to reveal changes at central carbon metabolism corresponding to both carbon sources.

RESULTS

Targeted and non-targeted metabolomics for both polar and semi-polar metabolites of Phialemonium curvatum AWO2 (DSM 23903) cultivated in MSM with palm oil (MSM-P) or glucose (MSM-G) as carbon sources were obtained. Targeted metabolomics on central carbon metabolism of tricarboxylic acid (TCA) cycle and glyoxylate cycle were analysed using LC-MS/MS-TripleQ and GC-MS, while untargeted metabolite profiling was performed using LC-MS/MS-QTOF followed by multivariate analysis. Targeted metabolomics analysis showed that glyoxylate pathway and TCA cycle were recruited at central carbon metabolism for triglyceride and glucose catabolism, respectively. Significant differences in organic acids concentration of about 4- to 8-fold were observed for citric acid, succinic acid, malic acid, and oxaloacetic acid. Correlation of organic acids concentration and key enzymes involved in the central carbon metabolism was further determined by enzymatic assays. On the other hand, the untargeted profiling revealed seven metabolites undergoing significant changes between MSM-P and MSM-G cultures.

CONCLUSIONS

Overall, this study has provided insights on the understanding on the effect of triglycerides and sugar as carbon source in fungi global metabolic pathway, which might become important for future optimization of carbon flux engineering in fungi to improve organic acids production when vegetable oil is applied as the sole carbon source.

Chemical composition and oxidative stability of eleven pecan cultivars produced in southern Brazil

Nuts are considered highly nutritious foods and a source of health-promoting compounds. Therefore, the aim of this study was to evaluate the chemical composition (proximate composition, fatty acids, volatile compounds, total phenolics, squalene, and β-sitosterol) of eleven pecan cultivars harvested in Rio Grande do Sul State (Brazil) and investigate their oxidative stability by the Rancimat method. 'Barton' is the main cultivar produced in Brazil and presented the highest protein, linoleic acid, and linolenic acid values and the lowest saturated fatty acid values, which provide health benefits. 'Mahan' showed the highest oxidation induction time, both in extracted oil and ground samples, low abundance of lipid oxidation compounds, low polyunsaturated fatty acids, high levels of oleic acid and β-sitosterol, which suggests potential for storage. 'Stuart' and 'Success' had the highest total dietary fiber values. Moreover, analysis showed that 'Chickasaw' and 'Success' had large quantities of compounds correlated to lipid oxidation, suggesting low stability for long-term storage. These results imply that the physicochemical characteristics and proximate composition of pecan nut cultivars from southern Brazil have variable parameters that may depend on their genetic variability.

Multivariate analysis for FTIR in understanding treatment of used cooking oil using activated carbon prepared from olive stone

In this study, activated carbons prepared from the green and black olive stone (green OSAC and black OSAC) were used as adsorbents to investigate their removal efficiencies for oxidation products and polar compounds from used sunflower and corn cooking oils. The degree of oxidation level and polar compounds were evaluated using Fourier transform infrared (FTIR) with the principal component analysis and ultra-performance liquid chromatography. Two FTIR absorption peaks were used for the oil evaluation, namely 3007-3009 cm-1, which is related to C-H symmetric stretching vibration of the cis double bonds, and ~1743 cm-1, which is related to = CH and ester carbonyl stretching vibration of the functional groups of the triglycerides, C = O. The principal component analysis results showed significant variations in the oxidation level of the sunflower and the corn oils occurred after consecutive heating and French fries frying for 10 days. The oxidation products that are adsorbed on the surface of the OSAC forms π-complexes with the C = C parts of the OSAC system. It can be concluded that the prepared adsorbents can be promising, efficient, economically effective, and environmentally friendly alternative adsorbents for oil treatment applications.

Chemoprotective and antiobesity effects of tocols from seed oil of Maqui-berry: Their antioxidative and digestive enzyme inhibition potential

Maqui-berry (Aristotelia chilensis) is the emerging Chilean superfruit with high nutraceutical value. Until now, the research on this commodity was focused on the formulations enriched with polyphenols from the pulp. Herein, contents of tocols were compared in the seed oil of Maqui-berry obtained through three different extraction methods followed by determining their antioxidative and enzyme inhibitions in-vitro. Firstly, oilseed was extracted with n-hexane (Soxhlet method), chloroform/methanol/water (Bligh and Dyer method) and pressing (industrial). These samples were used to access their effects against DPPH, HORAC, ORAC, FRAP, Lipid-peroxidation (TBARS), α-amylase, α-glucosidase, and pancreatic lipase. All the isomers of tocopherol and tocotrienol were identified, and β-sitosterol was the only sterol found in higher amounts than other vegetable oils. The Bligh and Dyer method could lead to the highest antioxidative capacity compared to Soxhlet and press methods likely because the latter have a higher amount of tocopherols. Further, seed oil from Maqui berry and their tocols (α, β, γ, δ-tocopherols, tocotrienols, and β-sitosterol) warrant clinical investigation for their antioxidative and antiobesity potential. Taken together, these findings provide relevant and suitable conditions for the industrial processing of Maqui-berry.

Direct Discrimination of Edible Oil Type, Oxidation, and Adulteration by Liquid Interfacial Surface-Enhanced Raman Spectroscopy

The quality and safety of edible oils is a momentous but formidable challenge, especially regarding identification of oil type, oxidation, and adulteration. Most conventional analytical methods have bottlenecks in sensitivity, specificity, accessibility, or reliability. Surface-enhanced Raman spectroscopy (SERS) is promising as an unlabeled and ultrasensitive technique but limited by modification of inducers or surfactants on metal surfaces for oil analysis. Here, we develop a quantitative SERS analyzer on two-liquid interfacial plasmonic arrays for direct quality classification of edible oils by a portable Raman device. The interfacial plasmonic array is self-assembled through mixing the gold nanoparticle (GNP) sols and oil sample dissolved in chloroform without any surfactants or pretreatments. Different kinds of edible oils dissolved in chloroform directly participate in self-assembly of plasmonic arrays that finally localizes onto a three-dimensional (3D) oil/water interface. The 3D plasmonic array is self-healing, shape adaptive, and can be transferred to any glass containers as a substrate-free SERS analyzer for direct Raman measurements. It produces sensitive responses of SERS on different kinds of edible oils. By virtue of principal component analysis (PCA), this analyzer is able to quickly distinguish six edible oils, oxidized oils, and adulterated oils. Moreover, the solvent chloroform generates unique and stable SERS bands that can utilized as an inherent internal standard (IIS) to calibrate SERS fluctuation and greatly improve quantitation accuracy. Compared to conventional lab methods, this analyzer avoids complex and time-consuming preprocessing and provides significant advantages in cost, speed, and utility. Our study illuminates a facile way to determine edible oil quality and promises great potential in food quality and safety analysis.

Stimulated Brillouin scattering in combination with visible absorption spectroscopy for authentication of vegetable oils and detection of olive oil adulteration

Vegetable oils provide high nutritional value in the human diet. Specifically, extra virgin olive oil (EVOO) possesses a higher price than that of other vegetable oils. Adulteration of pure EVOO with other types of vegetable oils has attracted increasing attentions. In this work, a stimulated Brillouin scattering (SBS) combined with visible absorption spectroscopy method is proposed for authentication of vegetable oils and detection of olive oil adulteration. The results provided here have demonstrated that the different vegetable oils and adulteration oils exhibit significant differences in normalized absorbance values of two relevant wavelengths (455 and 670 nm) and frequency shifts of SBS. The normalized absorbance values of all spectra at the two relevant wavelengths of 670 nm and 455 nm linearly decrease with the increase of the adulteration concentration. The Brillouin frequency shifts exponentially increase with the increase of the adulteration concentration. Due to non-destructive and requiring no sample pretreatment procedure, this method can be effectively employed for authentication and detection of oils adulteration.