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Avocado oil is a food product of high commercial and nutritional value. As a result, it can be a subject of adulteration similar to other high-value edible oils, such as olive oil. For olive oil and many other foods products, NMR spectroscopy has been successfully used for authentication and quality assessment. In this study, we apply NMR analysis to avocado oil to differentiate it from other oils including olive, canola, high-oleic (HO) safflower, HO sunflower and soybean oil using commercial and lab-made samples of avocado oils. NMR allowed the rapid analysis of the fatty acid profile and detection of minor compounds, such as sterols, oxidation products, and hydrolysis products, which can be used to assess oil quality and authenticity. The NMR assignment was conducted using traditional 2D NMR and the novel NOAH super-sequences. Combining chemometrics with NMR enabled us to differentiate between avocado oil and other oils. Avocado oil has compositional similarities with other vegetable oils, such as HO sunflower and HO safflower oil, which can be used as potential adulterants. Despite these similarities, NMR-based metabolomics captured differences in the levels of certain compounds including fatty acids, terpenes, sterols, and oxidation products to detect adulteration and for quality control purposes.

Kernel oxidation susceptibility and pellicle darkening are among the biggest concerns regarding walnut quality. Monitoring oxidation is crucial to preserve quality from production to consumption. Chemical oxidation parameters (peroxide value and UV absorbances), fatty acid profile, tocopherols, phenols, and volatiles in ‘Chandler’ and ‘Howard’ kernels were studied at different time points during 28 weeks of storage to evaluate potential oxidation markers. During storage, peroxide value, UV absorbances, and volatiles concentration increased; oxidative stability, phenols, and tocopherols decreased, while fatty acid profile was unaffected. ‘Chandler’ had a lower peroxide value, K232, and K268; and higher kernel and oil oxidative stability compared to ‘Howard’. Phenols and tocopherols decreased 1.2-fold in ‘Chandler’ and 1.3-fold in ‘Howard’. Using multivariate analysis, samples were discriminated in three groups according with their oxidative levels. Increases of volatiles in oil and kernel were associated with higher oxidative levels. Pentanal, 2-methylpropanal, hexanal, (E)-2-pentenal, 3-octanone, octanal, (Z)-2-penten-1-ol, hexanol, (E)-2-octenal, 1-octen-3-ol, benzaldehyde, (E,E)-2,4-nonadienal, and hexanoic acid in kernels were adequate at distinguishing oxidation levels and as oxidative markers in walnuts. Kernel volatiles is a useful measurement for walnut oxidation during storage without any prior fat extraction.

Abstract Background Edible oils often are included in recipes for home-prepared pet diets to supply essential fatty acids, but there may be discrepancies between database values and oil profiles. Furthermore, storage time and conditions influence quality. Hypothesis/Objectives Determine the fatty acid profiles of commonly used oils and characterize fatty acid oxidation under recommended storage conditions. Samples Fourteen products were purchased and stored according to label instructions, representing 2 brands each of walnut, corn, canola, and flaxseed oils, and 3 each of safflower and sunflower oils. Methods Samples were collected at baseline and at 6 and 12 months and stored at −80°C until analysis. Aliquots were analyzed for fatty acid profile at baseline and 12 months, and at all 3 timepoints for free fatty acidity, peroxide value, and induction time. Results Linoleic acid concentrations exceeded the United States Department of Agriculture (USDA) Food and Nutrient Database for Dietary Studies (FNDDS) values except for 2/3 sunflower and 1/3 safflower oil samples. Peroxide value was static for 3/14 products and significantly increased at 6 or 12 months for 11/14 products. Induction time was static for 2/14 products and significantly decreased at 6 or 12 months for 12/14 products. Conclusions and Clinical Importance Sunflower and safflower oils are not reliable sources of linoleic acid. Cold storage appeared to better maintain oil quality. Oils for home-prepared pet foods should be carefully selected to ensure nutritional adequacy and refrigerated to maintain quality, especially those high in polyunsaturated fatty acids, high omega-6:omega-3 ratios, or both.

Extra virgin olive oil (EVOO), with high unsaturation degree (oleic acid, linoleic acid, and linolenic acid), is prone to oxidation during production and storage even with the presence of abundant antioxidants (e.g., phenolic compounds, alpha-tocopherol, and chlorophyll). The level of oxidation degradation is greatly affected by the EVOO chemical composition (free fatty acids, saturated and unsaturated fat ratio, total phenol content, etc.) and storage conditions (packaging material, oxygen, temperature, and light). With the increasing demand on qualitative acceptability and food safety of an EVOO product, consumers rely heavily on “shelf life” as a good indicator. Hence, it is critical for olive oil producers to provide accurate and practical information on shelf-life prediction. This review analyzes ten shelf-life prediction models that used various parameters and approaches for model establishment. Due to the complexity of chemical interactions between oil phase and environment under real-time storage and rapid accelerated testing conditions, further investigation is needed to scrutinize and minimize the discrepancies between real-time shelf life and predicted shelf life of EVOO products.

With innovations and advancements in analytical instruments and computer technology, omics studies based on statistical analysis, such as phytochemical omics, oilomics/lipidomics, proteomics, metabolomics, and glycomics, are increasingly popular in the areas of food chemistry and nutrition science. However, a remaining hurdle is the labor-intensive data process because learning coding skills and software operations are usually time-consuming for researchers without coding backgrounds. A MATLAB® coding basis and three-in-one integrated method, ‘Ana’, was created for data visualizations and statistical analysis in this work. The program loaded and analyzed an omics dataset from an Excel® file with 7 samples * 22 compounds as an example, and output six figures for three types of data visualization, including a 3D heatmap, heatmap hierarchical clustering analysis, and principal component analysis (PCA), in 18 s on a personal computer (PC) with a Windows 10 system and in 20 s on a Mac with a MacOS Monterey system. The code is rapid and efficient to print out high-quality figures up to 150 or 300 dpi. The output figures provide enough contrast to differentiate the omics dataset by both color code and bar size adjustments per their higher or lower values, allowing the figures to be qualified for publication and presentation purposes. It provides a rapid analysis method that would liberate researchers from labor-intensive and time-consuming manual or coding basis data analysis. A coding example with proper code annotations and completed user guidance is provided for undergraduate and postgraduate students to learn coding basis statistical data analysis and to help them utilize such techniques for their future research.

Geographical origin assessment of extra virgin olive oil (EVOO) is recognised worldwide as raising consumers’ awareness of product authenticity and the need to protect top-quality products. The need for geographical origin assessment is also related to mandatory legislation and/or the obligations of true labelling in some countries. Nevertheless, official methods for such specific authentication of EVOOs are still missing. Among the analytical techniques useful for certification of geographical origin, nuclear magnetic resonance (NMR) and mass spectroscopy (MS), combined with chemometrics, have been widely used. This review considers published works describing the use of these analytical methods, supported by statistical protocols such as multivariate analysis (MVA), for EVOO origin assessment. The research has shown that some specific countries, generally corresponding to the main worldwide producers, are more interested than others in origin assessment and certification. Some specific producers such as Italian EVOO producers may have been focused on this area because of consumers’ interest and/or intrinsic economical value, as testified also by the national concern on the topic. Both NMR- and MS-based approaches represent a mature field where a general validation method for EVOOs geographic origin assessment could be established as a reference recognised procedure.

Traditional methods used to determine oil purity like fatty acids and sterols are time consuming and chemically wasteful; standards that utilize these methods require a large set of samples to cover natural variables to establish upper and/or lower limits for each compound. Due to this, it can be challenging to determine the purity of newer products on the market, like avocado oil, when standards have not yet been fully developed. Triacylglycerol analysis in tandem with principal component analysis (PCA) differs from these tradition methods; standard ranges for each triacylglycerol are not needed to determine purity. This study built on our earlier work on olive oil but used laboratory-made avocado oils accounting for a wide range of natural variables to measure avocado oil triacylglycerols and apply PCA to detect adulteration in avocado oil. This method had the same purity determination accuracy as traditional fatty acid and sterol methods, while being less time consuming, producing less chemical waste, easier to perform than the original methods with the added advantage that it can be utilized immediately by industry while official standards are still being developed.

Juglone is a quinone that has been associated with both deleterious environmental effects and potential health benefits, depending on the concentrations. At high concentrations, juglone can limit the growth of some plants and exert toxic responses on some animals. At low concentrations, juglone is safe and even fosters positive effects, e.g. reduces cancer cell growth. Therefore, determining the concentration of juglone in walnut industry byproducts, particularly shells and wood chips, is important to help evaluate their safety and utility to be used as value-added products. In this work, we optimized the juglone extraction procedure and quantitative analytical method via liquid chromatography. Three solvents (methanol, aqueous acetone, and chloroform) were compared. Methanol performed effectively for wood chips, and aqueous acetone was the optimum solvent for shells. Our data showed that juglone concentration in black walnut shells (0.45 ± 0.12 µg/g db) was similar to that in English walnut shells (0.74 - 1.70 µg/g db). Juglone concentrations in wood chips were 28.84 ± 1.54 and 65.50 ± 2.13 µg/g db for English and black walnuts, respectively. Shells and wood chips were considered safe because their juglone concentrations were lower than the level that adversely affects some animals and plants.

Olive pomace (OP) is a valuable food byproduct that contains natural phenolic compounds with health benefits related to their antioxidant activities. Few investigations have been conducted on OP from the United States while many studies on European OP have been reported. OP of Arbequina, the most common cultivar from California, was collected and extracted by water, 70% methanol and 70% ethanol, followed by purification using macroporous absorbing resin. Results showed that the extractable total phenolic content (TPC) was 36–43 mg gallic acid equivalents (GAE)/g in pitted, drum-dried defatted olive pomace (DOP), with major contributions from hydroxytyrosol, oleuropein, rutin, verbascoside, 4-hydroxyphenyl acetic acid, hydroxytyrosol-glucoside and tyrosol-glucoside. Macroporous resin purification increased TPC by 4.6 times the ethanol crude extracts of DOP, while removing 37.33% total sugar. The antioxidant activities increased 3.7 times Trolox equivalents (TrE) by DPPH and 4.7 times TrE by ferric reducing antioxidant power (FRAP) in the resin purified extracts compared to the ethanol crude extracts. This study provided a new understanding of the extraction of the bioactive compounds from OP which could lead to practical applications as natural antioxidants, preservatives and antimicrobials in clean-label foods in the US.

In California, over 3.4 million tons of wine grapes were crushed in 2020 while every year roughly 20% of the grape mass goes unused. Grape cluster thinning at veraison, a common agricultural practice to ensure color homogeneity in wine grapes, adds to the production costs and generates substantial on‐farm loss during grapevine cultivation in which the health‐promoting values of thinned clusters (unripe grapes) are usually overlooked. In particular, the health‐promoting properties of flavanol monomers, specifically (+)‐catechin and (−)‐epicatechin, and their oligomeric procyanidins, have been extensively studied in cocoa and chocolate but not so much in grape thinned clusters in recent epidemiology studies. As part of the important agricultural by‐products upcycling effort, the current study compared thinned clusters from Chardonnay and Pinot noir, two premium wine grape varieties cultivated in California, to a traditionally Dutch (alkalized) cocoa powder that has been widely used in food applications. Thinned cluster fractions from Chardonnay and Pinot noir grapes grown in the North Coast of California showed much higher concentrations of flavanol monomers and procyanidins, with 208.8–763.5 times more (+)‐catechin, 3.4–19.4 times more (−)‐epicatechin, and 3.8–12.3 times more procyanidins (by degree of polymerization DP 1–7) than those in the traditionally Dutch cocoa powder. These flavanol‐rich thinned clusters that are also considered as plant‐based natural products suggested great potential to be functional ingredients in cocoa‐based products—which have been ubiquitously perceived as flavanol‐rich products by consumers—to enhance their overall dietary flavanol content. Grape thinned cluster fractions from Chardonnay and Pinot noir grapes grown in the North Coast of California showed higher concentrations of flavanol monomers and procyanidins, with 208.8–763.5 times more (+)‐catechin, 3.4–19.4 times more (−)‐epicatechin, and 3.8–12.3 times more procyanidins (by degree of polymerization DP 1–7) than a traditionally Dutch (alkalized) cocoa powder that has been widely used in food applications. Thus, grape thinned clusters could be considered as plant‐based natural products suggesting great potential to be functional ingredients in cocoa‐based products to enhance their overall dietary flavanol content.