Concentrations Of Ethyl Esters Research Articles

Hydrothermal Co-Liquefaction of Sugarcane Bagasse and Residual Cooking Soybean Oil for Bio-Crude Production

Hydrothermal co-liquefaction (co-HTL) is a process involving two sources of biomasses aiming at bio-crude production. Since there is a lack of studies performed with sugarcane bagasse and residual soybean oil, this study investigated different conditions for the co-HTL of these biomasses, with and without the presence of ethanol as a co-solvent to maximize the bio-crude yield. All co-HTL reactions were carried out in a 300 mL Parr® reactor at temperatures ranging from 200 to 300 °C. After the reaction, a vacuum filtration was performed to separate the bio-char, later washed with ethanol to extract heavy bio-crude, while the liquid-phase was mixed with dichloromethane to recover light bio-crude. Bio-crude yields of around 95 wt.% were obtained at 300 °C using ethanol and water as solvents. The highest bio-char yield (16.6 wt.%) was achieved when using only sugarcane bagasse as the substrate, without the presence of soybean oil. Bio-crude samples obtained at higher temperatures (280 °C and 300 °C) using ethanol as a hydrogen donor presented higher contents of both free fatty acids and fatty acid ethyl esters. This work presents a promising process to produce high-quality bio-crude using an abundant feedstock (sugarcane bagasse) in the presence of a lipid source which could cause environmental problems if poorly handled.

Esters and higher alcohols regulation to enhance wine fruity aroma based on oxidation-reduction potential

Fruity aroma is a crucial element in reflecting the flavor of wine, believed to be closely linked to esters and higher alcohols associated with the oxidation-reduction potential (ORP) of wine. In this work, the impact of ORP on the production of esters and higher alcohols, and consequently the fruity aroma in Cabernet Sauvignon (CS) and Ecolly wines were investigated. Results revealed that the maximum concentration of medium-chain fatty acid ethyl esters (MCFAEEs) was achieved at −80 mV, which was 48.78% and 25.10% higher than those of the CK groups (ORP without artificial control) in CS and Ecolly wines, respectively. However, the concentrations of acetates and higher alcohols in CS were not significantly different from that in CK, while those in Ecolly were elevated. Additionally, the temperate fruity aroma in CS and citrus aroma in Ecolly wines were enhanced at −80 mV. Partial least-squares regression further indicated that, higher alcohols contributed positively to these enhanced aromas of CS and Ecolly. MCFAEEs have also been suggested to have a positive impact on the fruity and floral aromas for CS and tropical fruity aroma for Ecolly wines. Our work provides an alternative for improving the aroma quality of wine through fermentation process.

The Influence of Prefermentation Skin Contact, Stabulation, and Skin Fermentation on the Aromatic Behaviour and Phenolic Compounds of Important Austrian White Wine Cultivars

Many varietal aromas of wine are located in the berry skin. In the present study, we evaluated four important Austrian grape varieties: Grüner Veltliner, Sauvignon Blanc, Traminer, and Pinot Blanc. We assessed whether prefermentation skin contact, fermentation with the skin (only for Grüner Veltliner), and stabulation (lees stirring; only for Sauvignon Blanc, Traminer, and Pinot Blanc) could enhance the varietal aromas of the different grape cultivars. The aim was to intensify the varietal aromas without extracting the undesirable phenols. We performed a detailed analytical characterisation of approximately 100 volatile and phenolic compounds as well as a sensory characterisation. Although mash fermentation significantly increased the spicy aromas of Grüner Veltliner, which are affected by climate change (especially the sesquiterpene rotundone), it markedly decreased the fruitiness and increased the bitterness; therefore, it cannot be recommended for this cultivar. For Sauvignon Blanc, stabulation is a possible option; the varietal aromas (thiols and methoxypyrazines) were increased in the final wines of these variants. For Pinot Blanc and Traminer, prefermentation skin contact yielded the best results: for Traminer, it produced the highest content of monoterpenes (especially z-rose oxide), and for Pinot Blanc, it produced the highest content of ethyl esters. To summarise, stabulation will not completely replace classic skin contact, and mash fermentation is certainly not an alternative for the production of standard Grüner Veltliner wine. However, additional investigations are necessary with regard to other grape varieties, terroirs, and vintages before we can make final recommendations.

Влияние винных и виноградных спиртов на качество напитков из виноградного сырья

Table grapes that have lost their marketable appearance are considered waste products. However, such grapes still possess some technological properties that make it possible to use them as a raw material for wine and grape spirits. This research featured the effect of the composition and technology of table grape alcohols on the volatile compounds and sensory profile 
 of grape beverages.
 The study involved six white and six red grape beverages. In the test samples, the fermentation process was stopped by adding wine spirits and grape spirits obtained by rectification of distillates from table grapes. In the control samples, the procedure involved rectified grain alcohol. The physicochemical parameters of drinks and spirits were defined by standard methods. The highly volatile compounds were determined by gas chromatography. The sensory assessment was conducted by panelists from the Winemaking Research Center of the North-Caucasian Federal Scientific Center of Horticulture, Viticulture, and Winemaking.
 In this study, the wine spirits and the grape spirits obtained from table grapes had no effect on the standard indicators, e.g., volatile acids and acetoin. However, they increased the mass concentrations of highly volatile compounds in the following manner: drinks with grain alcohol ˂ drinks with wine alcohol ˂ drinks with grape alcohol. The content of acetaldehyde increased by 10–14% while the contents of ethyl acetate, esters, and higher alcohols increased by 25–35, 4.5–8.5, and 15%, respectively. The furfural content increased by 0.4–1.4 mg/L in the samples with grape alcohol. The samples with white grape varieties acquired a more prominent floral-honey flavor whereas those with black grapes acquired hints of hazelnut and honey.
 As a result of the study, it was found that wine alcohol and grape alcohol moderately increased the content of volatile compounds in drinks and had a positive effect on their sensory perception, which proves the expediency of their use in beverage technology.

Screening and characterization of indigenous non-Saccharomyces cerevisiae with high enzyme activity for kiwifruit wine production

To explore the diversity and fermentation potential of non-Saccharomyces cerevisiae associated with kiwifruit, indigenous yeasts isolated from kiwifruit and natural fermentation were comprehensively analyzed. A total of 166 indigenous yeasts were isolated, of which 54 representative strains were used for subsequent enzyme activity characterization. Different colorimetric methods were used to verify the ability of these strains to secrete hydrolytic enzymes, and then six strains were selected for sequential fermentation by specific activity assay. The performance of indigenous yeasts in improving organic acids, polyphenols, volatile compounds and sensory characteristics of wines was evaluated holistically. Results indicated that most sequential fermentations exhibited significant improvements in vitamin C and polyphenols. Remarkably, the involvement of Zygosaccharomyces rouxii, Meyerozyma guilliermondii, and Pichia kudriavzevii increased the concentrations of ethyl esters, acetates and alcohols, enhancing floral and tropical fruit odors and ultimately achieving the highest overall sensory acceptability, thereby highlighting their potential in kiwifruit wine fermentation.

The influence of different yeast strains and yeast nutrients on the aroma of Krstač and Žižak wines

Krstač and Žižak are autochthonous grape varieties grown in Montenegro. Although international varieties are more popular, the autochthonous varieties are very important, especially for countries developing tourism. The fermentation aromas produced during alcoholic fermentation contribute significantly to wine quality. The effects of yeasts (Saccharomyces cerevisiae and Saccharomyces bayanus) and yeast nutrients (Fermaid E and Fermaid O) on aromatic compounds in wines were investigated. Using GC/FID-MS analysis, aroma compounds in Krstač and Žižak wines were characterized and quantified. Wines produced with the addition of yeast and yeast nutrients had mostly lower total alcohol content than wines obtained by spontaneous fermentation of Krstač and Žižak varieties. The results of this study showed that the concentration of compounds depends on the yeast strains. The yeast S. cerevisiae (ICV) provided a higher content of higher alcohols, while S. bayanus produced a higher concentration of esters and (medium chain) fatty acids. Total ester content ranged from 3.34 to 11.97 mg/l for Krstač wines and 8.51 to 13.68 mg/l for Žižak wines. Among all wines, Krstač and Žižak wines produced with S. bayanus and Fermaid E addition had the highest concentration of total esters. The yeast nutrients Fermaid E and O emphasized different characteristics of the yeasts. They had a statistically significant effect on the content of ethyl and acetate esters. The highest overall scores were obtained for ICVE and BayE Krstač wines (18.1 out of 20 points) and Žižak ICVE wine (18.2 out of 20 points).

Inoculation of Yarrowia lipolytica promotes the growth of lactic acid bacteria, Debaryomyces udenii and the formation of ethyl esters in sour meat

Yarrowia lipolytica N12 and A13 with high lipase activity obtained by mutagenesis were inoculated into sour meat, and their effects on physicochemical properties, microbial community succession, free amino acids, and volatile compounds of sour meat were investigated. Inoculation fermentation increased the contents of free amino acids observably, rapidly reduced pH, promoted the accumulation of total acids, decreased 2-thiobarbituric acid reactive substances (TBARS) values. In addition, the addition of Y. lipolytica might contribute to the growth of lactic acid bacteria, Candida spp., and Debaryomyces udenii, which play an important role in production of volatile compounds. It was shown that inoculation promoted the production of esters, aldehydes, and alcohols, especially ethyl esters, giving sour meat a better meat flavor. Besides, it was found that Y. lipolytica A13 had better fermenting property. Sample of A13 group had higher contents of ethyl esters, free amino acids and dominant microorganisms. The results may help to provide new strains for sour meat fermentation.

Wine aroma modification by Hanseniaspora uvarum: A multiple-step strategy for screening potential mixed starters

Hanseniaspora uvarum is a prevalent yeast species in vineyards. However, its application in grape wine fermentation remains limited. This study used culture-dependent and -independent approaches to investigate the dynamics of H. uvarum during the spontaneous fermentation of Cabernet Sauvignon grapes. The results revealed that H. uvarum constituted 77.49 % of the non-Saccharomyces yeast population during fermentation. An indigenous strain, QTX-C10, was isolated from the 148 H. uvarum strains using a multistep screening strategy. The 1:1 co-inoculation of QTX-C10 with Saccharomyces cerevisiae proved to be an optimal strategy for mixed fermentation, resulting in a 48.54 %–59.55 % increase in ethyl esters in Cabernet Sauvignon wine and a 96.94 %–110.92 % increase in Chardonnay wine. Furthermore, this approach reduced the acetic acid levels by 12.50 %–17.07 % for Cabernet Sauvignon wine and 10.81 %–17.78 % for Chardonnay wine. Additionally, increased ethyl ester content may enhance the tropical fruit flavor of Cabernet Sauvignon wines.

Identification of volatile organic compounds as markers to detect Monilinia fructicola infection in fresh peaches

Monilinia spp. are among the main fungal pathogen affecting peaches, and they can cause severe pre- and postharvest losses. Development of smart packaging technologies (e.g., volatile indicators), facilitating infection detection and preventing other fruit from being contaminated, is still limited. In this study, we compared for the first time the aroma profile of whole healthy fresh peaches to Monilinia fructicola-artificially inoculated peaches, identifying discriminant volatile organic compounds (VOCs). More than one hundred VOCs were detected by applying head space solid-phase microextraction followed by GC-MS analysis. The level of methyl esters, hydrocarbons, lactones, and acids decreased in infected peaches indicating fruit aroma deterioration, while the concentration of ethyl esters and alcohols increased. In particular, the amount of ethanol and derived ethyl acetate reached a maximum of 24- and 20-fold increase in the infected peaches, respectively. Isobutanol, propyl acetate, and ethyl isovalerate were specifically emitted by M. fructicola-infected peaches. These compounds might serve as markers for the development of smart sensors allowing the detection of fungal infection.

The regulatory effects of microbial community on the formation of higher alcohols and volatile flavor components in Hongqu rice wine brewing

The contents of higher alcohols (HAs) and volatile components produced by microbial metabolism largely determine the drinking comfort and flavor quality of Hongqu rice wine. The purpose of this study was to compare the differences of volatile flavor profile and microbial community in the brewing process of Hongqu rice wines with low and high HAs content (LHA and HHA). The results showed that the main HAs in Hongqu rice wine were isobututyl alcohol, isoamyl alcohol, phenylethyl alcohol, and the total content of HAs in HHA (749.07 ± 20.47 mg/L) was much higher than that in LHA (407.61 ± 20.80 mg/L). Multivariate statistical analysis and visualization showed that the volatile flavor characteristics of HHA and LHA were significantly different, and the contents of ethyl esters, medium- and long-chain fatty acids in HHA were higher than those in LHA. Microbiome analysis based on metagenomic sequencing indicated that fermentation starter has significant effect on the composition of microbial community during Hongqu rice wine brewing. Microbial species such as Cronobacter sakazakii, Weissella paramesenteroides, Klebsiella pneumoniae, Aspergillus niger, Millerozyma farinosa and Rhizopus delemar were significantly enriched in HHA brewing, while Pediococcus pentosaceus, Lactobacillus curvatus, Leuconostoc pseudomesenteroides and Leuconostoc mesenteroides were significantly enriched in LHA brewing. Furthermore, the potential relationships between the key microbial species and characteristic volatile components were revealed through correlation heatmap analysis. Bioinformatical analysis revealed that the abundances of microbial genes encoding enzymes involved in HAs metabolism were higher in HHA than LHA, but the gene abundance of phenylacetaldehyde dehydrogenase in LHA was significantly higher than that in HHA, which could limit the formation of HAs during Hongqu rice wine brewing. Collectively, this study provides important scientific data for enhancing the flavor quality of Hongqu rice wine, and lays a solid foundation for the healthy development of Hongqu rice wine industry.

Non-Saccharomyces Yeast Strains, Aromatic Compounds and Sensory Analysis of Italy and Negra Criolla Pisco from the Moquegua Region of Peru

In this study, we aimed to isolate and phenotypically characterize non-Saccharomyces yeast strains (NSYSs) from the skin of aromatic (Italy) and non-aromatic (Negra Criolla) grapes from vineyards in Moquegua, Peru, typically used for the production of pisco. Our second objective was to characterize the volatile compounds and sensory attributes of pisco made from these grapes. Pichia terricola (56%), Metschnikowia pulcherrima (31%), and Naganishia vaughanmartiniae (13%) were the main NSYSs isolated from the skin of aromatic Italy grapes and identified; meanwhile, Vishniacozyma carnescens (50%), Vishniacozyma heimaeyensis (30%), and Aureobasidium pullulans (20%) were identified on the skin of the non-aromatic Negra Criolla grapes. These NSYSs showed different capacities in terms of carbohydrate fermentation, polygalacturonase activity, ethanol tolerance, sulphite production, and nitrogen consumption. Moreover, the pisco resulting from these varieties of grape had different volatile profiles. Terpene alcohols such as citronellol, geraniol, linalool, and nerol were found in pisco made from Italy grapes, while higher contents of 2-phenylacetate and ethyl esters were found in Negra Criolla Pisco. Intermediate levels of both 1-hexanol and bencyl alcohol were also found in all the pisco. Sensory analysis performed by a trained pisco tasting panel showed that citric, floral, alcohol, and syrup descriptors were more marked in Italy Pisco, while nuts, syrup, alcohol, and floral were the most intense attributes of Negra Criolla Pisco. These results will contribute to determining the potential of indigenous grape yeasts from the Moquegua region as fermentation starters to improve the typical sensory qualities of the pisco produced in this region, which deserves further study.

Sequential fermentation with indigenous non-Saccharomyces yeasts and Saccharomyces cerevisiae for flavor and quality enhancement of Longyan dry white wine

In this study, we investigated the effect of the sequential fermentation of four selected indigenous non-Saccharomyces yeasts (Candida stellimalicola HL-S-5, Rhodotorula mucilaginosa HL-S-8, Hanseniaspora uvarum HL-S-9, and Pichia kluyveri XL-48-6) and Saccharomyces cerevisiae VL2 on the oenological parameters, volatile compositions, organic acids, and sensory characteristics of Longyan dry white wine. Results showed that the ethanol concentration of pure fermentation (11.12 ± 0.04%, v/v) was the highest among all fermentations. Furthermore, the aroma concentrations produced by the fermentation of R. mucilaginosa HL-S-8/VL2 (9929.35 ± 96.87 μg/L) and P. kluyveri XL-48-6/VL2 (9017.67 ± 85.91 μg/L) were significantly higher than that of VL2 (7654.64 ± 397.07 μg/L). In particular, the treatment of R. mucilaginosa HL-S-8/VL2 increased the content of acetic esters (512.11 ± 12.92 μg/L) and fatty acid ethyl esters (6893.64 ± 56.67 μg/L), which enhanced fruity and floral characteristics. The sequential fermentation of R. mucilaginosa HL-S-8/VL2 led to significantly higher organic acid content (3843.32 ± 73.93 mg/L) than the other samples. Moreover, the sequential fermentation of R. mucilaginosa HL-S-8/VL2 wine samples resulted in the highest scores in sensory evaluation. Therefore, the sequential fermentation of R. mucilaginosa HL-S-8/VL2 was an effective way to improve wine flavor and quality. This work will provide a useful reference for improving the flavor and quality of Longyan wine through non-Saccharomyces cerevisiae.

Effect of Different Vinification Techniques on the Concentration of Volatile Aroma Compounds and Sensory Profile of Malvazija Istarska Wines

The majority of chemical compounds that contribute to varietal aroma originate from grape skin. To investigate the differences between volatile aroma compounds when different maceration conditions are applied, a total of six vinification treatments were carried out on Malvazija istarska (Vitis vinifera L.) variety, non-maceration control treatment (C), pre-fermentative two days cryomaceration treatment at 8 °C (CRYO), seven days maceration treatment at 16 °C (M7), 14 days maceration treatment at 16 °C (M14), and prolonged post-fermentative maceration treatments at 16 °C for 21 day (M21) and 42 days (M42). Wines were subjected to GC/MS and sensory analysis. Obtained results showed that prolonged post-fermentative maceration treatments contained the highest concentration of total volatile aroma compounds, precisely monoterpenes, alcohols, and other esters. Contrary, C and CRYO wines resulted in highest concentration of ethyl and acetate esters, and fatty acids. In addition, sensory analysis showed that longer maceration treatment wines (M14, M21, M42) were characterized by more aroma complexity, varietal flowery typicity, pronounced fruitiness, with accentuated dried fruit, moderate honey, and herbal notes. Obtained results can provide valuable information to producers when choosing an appropriate vinification technique based on the desired wine style which may lead to a further diversification of white wine market.

The influence of yeast format and pitching rate on Scotch malt whisky fermentation kinetics and congeners

Yeast format and pitching rate are variables which can be easily manipulated in a distillery environment but are seldom altered. Fermentations using dried and liquid yeast were studied at laboratory scale and compared by application of a 4-parameter logistic model to measurements of the decline in apparent extract during fermentation. Congener analysis of new make distillate allowed comparison between compounds of interest produced during fermentation. The liquid yeast format demonstrated a significant reduction (p<0.05) in lag time, which was 68% shorter than dried yeast. Despite this, longer overall fermentation times were observed due to a slower exponential phase as compared to the dried yeast format. Alteration of the yeast pitching rate using dried and liquid formats, demonstrated that high rates resulted in reduced lag times. The maximum fermentation rates (Vmax) were assessed from the fermentation models and no consistent trend could be identified. Dried yeast was observed to achieve its maximum fermentation rate when underpitched. Substantially higher Vmax ­values were obtained with overpitched liquid yeast fermentations, resulting in faster fermentations, compared to underpitched liquid yeast fermentations. The liquid yeast format created more esters compared to dried yeast. The concentration of ethyl esters generally trended downwards for fermentations pitched with less yeast which fully attenuated. By combining the results of these studies, distillers can make informed decisions to optimise spirit character, quality, and distillery production.

Impact of glucose oxidase treatment in high sugar and pH musts on volatile composition of white wines

Climate change is modifying the composition of the grapes, increasing sugar and pH levels, which produces unbalanced wines with high alcohol degree, low acidity and poor aromatic notes. In this study, glucose oxidase (GOX) and catalase (CAT) were applied in white must with high sugar content and pH (>3.8) to simultaneously decrease glucose concentration and pH. The effect of enzyme treatment on volatile composition of wine was investigated. A concentration of 0.17 mkat/L for both GOX and CAT was sufficient to produce a remarkable reduction of glucose concentration in the must (61.5 g/L), achieving similar results within the pH range of 3–4. The musts subjected to enzymatic treatment yielded more balanced wines, lowering their alcohol content by 10–27 mL/L and pH by 0.3–0.5, while leaving their chromatic characteristics unchanged compared to the control wines. As positive effects, enzyme treatment reduced the concentrations of C6-alcohols with green-herbaceous notes and high-chain ethyl esters with soapy notes in wines, and did not modify the concentrations of short-chain ethyl esters, acids and higher alcohols. However, the concentrations of heptyl acetate and 2-phenylethanol with floral notes, and some ketones with floral and fruit notes, were lower in wines from treated musts.

Triethanolamine-based deep eutectic solvents as cosolvents in biodiesel production from black mustard (Brassica nigra L.) seed oil

The application of triethanolamine (TEOA)-based deep eutectic solvents (DESs) with glycerol (G), propylene glycol (PEG), 1,3-dimethylurea (DMU), ethylene glycol (EG), menthol (M), oleic acid (OLA), decanoic acid (DEA), and choline chloride (ChCl) (1:1, 1:2 or 2:1 mol/mol) in the CaO-catalyzed black mustard seed oil (BMSO) ethanolysis was studied. The ethanolysis was performed at 70 ºC, 12:1 ethanol-to-oil molar ratio, 20% DES, and 10% CaO (to BMSO). It was accelerated by the DESs with G, PEG, ChCl, DMU, M, and DEA and resulted in a higher fatty acid ethyl ester (FAEE) content (≥95.2 ± 0.6%) in 15 min than the control reaction. The TEOA:ChCl DES was most effective, providing within only 1.5 min an FAEE content of about 98.5%. With the TEOA:M and TEOA:PEG DESs, the FAEE content of over 91% was achieved for this time. Furthermore, the final product separation was achieved faster with all the applied DES than in the control reaction. With the TEOA:M and TEOA:ChCl DESs, separation was achieved immediately after the stopping of mixing and for 1 min, respectively. Two kinetic models were used for modeling the BMSO ethanolysis over CaO assisted by the TEOA:ChCl DES. The CaO reusability in three runs exceeded the FAEE content of 90%.

Oenological characteristics of two indigenous Starmerella bacillaris strains isolated from Chinese wine regions.

To broaden knowledge about the oenological characteristics of Starmerella bacillaris, the influence of two Chinese indigenous S. bacillaris strains on the conventional enological parameters and volatile compounds of Cabernet Sauvignon wines were investigated under different inoculation protocols (single inoculation and simultaneous/sequential inoculation with the commercial Saccharomyces cerevisiae EC1118). The results showed that the two S. bacillaris strains could complete alcohol fermentation alone under high sugar concentrations while increasing the content of glycerol and decreasing the content of acetic acid. Compared with wines fermented by EC1118 single inoculation, S. bacillaris single inoculation and S. bacillaris/EC1118 sequential inoculation increased the contents of isobutanol, ethyl isobutanoate, terpenes, and ketones and decreased the contents of isopentanol, phenylethyl alcohol, fatty acids, acetate esters, and total ethyl esters. Furthermore, for S. bacillaris/EC1118 simultaneous inoculation, the concentrations of ethyl esters were increased, contributing to a higher score of "floral" and "fruity" notes in agreement with sensory analysis. KEY POINTS: • S. bacillaris single and simultaneous/sequential inoculation. • Conventional enological parameters and volatile compounds were investigated. • S. bacillaris/EC1118 simultaneous fermentation increased ethyl esters.

Determination of four fatty acid ethyl esters in olive oil by solid phase extraction-gas chromatography

The fatty acid ethyl ester (FAEE) content of olive oil is an important indicator of its quality. At present, the international standard method used to detect FAEEs in olive oil is silica gel (Si) column chromatography-gas chromatography (GC); however, this technique presents a number of disadvantages, including complex operation, long analysis times, and high reagent consumption. In this study, a method based on Si solid phase extraction (SPE)-GC was established to determine four FAEEs in olive oil, namely, ethyl palmitate, ethyl linoleate, ethyl oleate, and ethyl stearate. First, the effects of the carrier gas were investigated, and He gas was ultimately selected as the carrier gas. Next, several internal standards were screened, and ethyl heptadecenoate (cis-10) was determined as the optimal internal standard. The SPE conditions were also optimized, and the effects of different brands of Si SPE columns on the recoveries of analytes were compared. Finally, a pretreatment method in which 0.05 g of olive oil was extracted with n-hexane and purified through a Si SPE column (1 g/6 mL) was developed. A sample could be processed within approximately 2 h using a total reagent volume of about 23 mL. Validation of the optimized method revealed that the four FAEEs have good linearities within the range of 0.1-5.0 mg/L (coefficients of determination (R2)>0.999). The limits of detection (LODs) of the method were within 0.78-1.11 mg/kg, and its limits of quantification (LOQs) were in the range of 2.35-3.33 mg/kg. The recoveries ranged from 93.8% to 104.0% at all spiked levels tested (4, 8, and 20 mg/kg), and the relative standard deviations were 2.2%-7.6%. Fifteen olive oil samples were tested using the established method, and the total FAEEs of three extra-virgin olive oil samples were found to exceed 35 mg/kg. Compared with the international standard method, the proposed method has the advantages of simpler pretreatment process, shorter operation time, lower reagent consumption and detection cost, high precision, and good accuracy. The findings provide an effective theoretical and practical reference for improving olive oil detection standards.

Analysis of the chemical composition and biological activity of secondary residues of Turkish Gall treated by semi-bionic technology

In order to meet the contemporary concept of sustainable development, the reuse of biological waste has also been emphasized. Lots of papers nowadays study the extraction of primary residues. The disposal of secondary residues is often neglected. The chemical composition and biological activity of secondary residues of Turkish Gall (SRTG) were researched in this paper. We selected five methods to extract the SRTG, and the extraction conditions were water, hydrochloric acid buffer (pH = 2), artificial gastric juice (pH = 2), phosphate buffer (pH = 6.8), and artificial intestinal solution (pH = 6.8). The changes of phenolic components were determined by spectrophotometry and high-performance liquid chromatography. The acid-base environment did not affect total polyphenols contents and gallic acid ethyl ester contents in SRTG. But it affected the gallic acid contents in SRTG. The contents of gallic acid in the hydrochloric acid buffer extraction groups were 1.63 times that of the water extraction group. The SRTG were extracted by hydrochloric acid buffer also had better inhibition on Escherichia coli and Staphylococcus aureus. In addition, SRTG showed positive effects on 1,1-Diphenyl-2-picrylhydrazyl Free, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), ·OH radicals, and Ferric ion reducing antioxidant power. Some active components of SRTG can be effectively released through the digestion of simulated gastric juices in vitro. The change of active ingredients affects the antibacterial and antioxidant capacity. The results provide data support for the conversion of secondary residues into products, such as feed additives. The SRTG has certain contributes to the value of the circular economy.Graphical

Volatile and sensory characterization of Tempranillo wines aged in Quercus alba oak barrels of different geographical origins in USA

Recent studies have shown the effect of barrel aging on the wine aroma composition not only depend on the wood specie but also on the geographical origin of the wood. However, there are no studies on the effect of oak barrels from different areas of the USA. Therefore, the aim of this work was to age Tempranillo red wines in Quercus alba oak barrels from four different origins of the United States, Missouri (M), Ohio (O), Kentucky (K), and Pennsylvania (P), and to study the volatile composition and olfactory attributes of the wines after 6 and 12 months of aging. Data revealed that the different origins produced wines with very different aromatic profile, especially after 6 months of aging. Wines aged 6 months in M and P barrels showed the highest Odour Activity Value (OAV) and highest concentrations of volatile compounds related to floral, fruity aromas, and wood-related compounds. Wines aged 12 months in M barrels maintained the highest OAV of wood aromas, high contents of acetates, furanic compounds and vanillin, and the highest contents of ethyl esters, γ-lactones, β-methyl-γ-octalactones and eugenol. Wines aged 12 months in M and K were the best valued in terms of global aromatic perception.