Sherry Vinegar Research Articles

Thermotolerant acetic acid bacteria in the production of a red wine vinegar by surface culture at different temperatures: volatile and polyphenolic composition

This work aims to determine the effect on the aromatic profile and phenolic content of red wine vinegars produced by surface culture at two different temperatures (30 °C and 37 °C) and using different inocula of acetic acid bacteria (Acetobacter malorum, Gluconobacter oxydans and a mixture of bacteria isolated from a Sherry vinegar). Fifty-seven volatile compounds and 23 polyphenolic and furfural compounds were identified. Vinegars obtained at 37 °C had poorer volatile profiles, with no significant influence of the strain of acetic bacteria. For polyphenolic content, temperature was also the most significant variable, so that the vinegars produced at higher temperatures had lower total anthocyanin contents, while no clear trend was observed regarding the influence of temperature on the low-molecular-weight phenolic constituents. The total tannin content in the vinegars obtained experienced slight increases after acetification, although this was not affected by temperature, and it was observed that when using the mixture of acetic acid bacteria from the Sherry vinegar, the total tannin content was significantly higher than when individual bacteria cultures of Acetobacter malorum or Gluconobacter oxydans were used. Temperature appears as a key parameter for the volatile and phenolic composition of red wine vinegar versus the use of different acetic acid bacteria.

Comparative study on the use of seasoned or unseasoned casks made of wood from different origins for the ageing of Sherry vinegar.

In the present study, the ageing process of Sherry vinegar in used (seasoned) or new casks made of chestnut, American oak, Spanish oak or French oak wood has been investigated, considering that no research has investigated whether this seasoning has a definite influence on the final composition of the aged beverage. The polyphenolic and volatile contents of the aged vinegars were determined and their sensory properties were evaluated. Different statistical tools were applied to the data collected. With respect to polyphenolic contents, ageing time was the most influential factor, followed by the seasoned-cask factor. The type of wood was only significant for gallic acid, p-hydroxybenzoic acid, methylfurfural, ethyl gallate, ferulic acid, coniferyl aldehyde and sinapaldehyde. Principal component analysis according to polyphenols did not allow the samples to be differentiated, whereas cluster analysis revealed a slight grouping trend according to ageing time and seasoning of the wood. In relation to volatile compounds, variance analysis revealed that, again, ageing time and cask-seasoning were the most significant factors, with the samples clustering according to these two parameters. Following the sensory study, a clear difference between seasoned and new cask vinegars could be established as a result of the high scores in olfactory quality obtained for those vinegars aged in new casks. This was probably because of an excess of the descriptor 'ethyl acetate' exhibited by seasoned-cask Sherry vinegars. The previous seasoning of the casks together with the ageing time conditioned the composition of the vinegars aged in casks of different botanical origin, which translated into differences at a sensory level. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Unraveling seasonings impact on cooked rice quality: Technological and nutritional implications for sushi

Sushi has become a worldwide consumed exotic dish, due to its flavor and texture, provided by the Koshihikari rice and the sushi seasoning (vinegar, sugar and salt). Nevertheless, limited information exists on the seasoning and cooked rice characteristics. Aim was to understand the effect of sushi seasoning, made with different vinegars from cereals and fruits, on the technological quality and in vitro digestibility of cooked rice. Raw and cooked Koshihikari rice were characterized, besides the vinegars used for making sushi seasoning, and their effect on the texture and hydrolysis of cooked rice. Koshihikari rice showed 66.4 °C gelatinization temperature and enthalpy (ΔH) of 4.09 ± 0.61 J/g. While vinegars presented differences in acidity (2.9–7.0%), sugar content and organic acid profile. The chemical composition of the vinegar affected the acidity, texture properties and in vitro starch hydrolysis (extension of hydrolysis) of flavored cooked rice. Sherry vinegar produced the highest acidity and adhesiveness, and citrus vinegar increased the extent of starch hydrolysis, likely due to its low acetic acid and high citric and tartaric acid contents. Using different type of vinegars for seasoning cooked rice allows extending the food quality characteristics with significant impact on health aspects.

Influence of Different Bacteria Inocula and Temperature Levels on the Chemical Composition and Antioxidant Activity of Prickly Pear Vinegar Produced by Surface Culture.

This work intends to determine the effect on the aroma profile, phenolic content and antioxidant activity of prickly pear vinegars produced by the surface culture at two different fermentation temperatures and using different acetic acid bacteria (AAB) inocula. Prickly pear wine was fermented at two temperature levels (30 and 37 °C) by using bacteria inocula containing Acetobacter, Gluconobacter or a mixture of bacteria isolated from Sherry vinegars. Eighty-five individual volatile compounds from different families and sixteen polyphenolic compounds have been identified. It was confirmed that the highest temperature tested (37 °C) resulted in a lower concentration of volatile compounds, while no significant effect on the vinegars’ volatile composition could be associated with the AAB inoculum used. Contrariwise, the highest content of polyphenolic compounds was detected in those vinegars produced at 37 °C and their concentration was also affected by the type of AAB inoculum used. Prickly pear wine displayed greater antioxidant activity than juices or vinegars, while the vinegars obtained through the mixture of AAB from Sherry vinegar showed higher antiradical activity than those obtained through either of the two AAB genera used in this study. It can be therefore concluded that, although the volatile content of vinegars decreased when fermented at a higher temperature, vinegars with a higher content in polyphenols could be obtained by means of partial fermentations at 37 °C, as long as thermotolerant bacteria were employed.

A Methodology Based on FT-IR Data Combined with Random Forest Model to Generate Spectralprints for the Characterization of High-Quality Vinegars.

Sherry wine vinegar is a Spanish gourmet product under Protected Designation of Origin (PDO). Before a vinegar can be labeled as Sherry vinegar, the product must meet certain requirements as established by its PDO, which, in this case, means that it has been produced following the traditional solera and criadera ageing system. The quality of the vinegar is determined by many factors such as the raw material, the acetification process or the aging system. For this reason, mainly producers, but also consumers, would benefit from the employment of effective analytical tools that allow precisely determining the origin and quality of vinegar. In the present study, a total of 48 Sherry vinegar samples manufactured from three different starting wines (Palomino Fino, Moscatel, and Pedro Ximénez wine) were analyzed by Fourier-transform infrared (FT-IR) spectroscopy. The spectroscopic data were combined with unsupervised exploratory techniques such as hierarchical cluster analysis (HCA) and principal component analysis (PCA), as well as other nonparametric supervised techniques, namely, support vector machine (SVM) and random forest (RF), for the characterization of the samples. The HCA and PCA results present a clear grouping trend of the vinegar samples according to their raw materials. SVM in combination with leave-one-out cross-validation (LOOCV) successfully classified 100% of the samples, according to the type of wine used for their production. The RF method allowed selecting the most important variables to develop the characteristic fingerprint (“spectralprint”) of the vinegar samples according to their starting wine. Furthermore, the RF model reached 100% accuracy for both LOOCV and out-of-bag (OOB) sets.

Application of Microwaves as an Advanced Technique for the Development of Sherry Vinegar Macerated with Pineapple

This work proposes the elaboration of a product based on the maceration of Sherry Vinegar together with pineapple in order to extract certain volatile compounds that can be found in pineapples, giving a final product with new organoleptic properties and increased polyphenolic content. Maceration trials were carried out with the application of microwaves and ultrasound, which reduced the maceration time from the traditional three-day solid-liquid maceration to just a few minutes. In addition, through maceration, the total polyphenol index increased significantly with respect to unmacerated vinegar, and the volatile profile of the vinegars was significantly modified. The tasting scores placed the pineapple macerated vinegar sample obtained by traditional maceration in the first place with respect to pineapple aroma; however, the microwave extraction samples were better rated in terms of overall quality. It can be concluded that the application of extracting energies, such as microwaves, can be a viable alternative for the production of sherry vinegar macerated with pineapple.

Use of ultrasound at a pilot scale to accelerate the ageing of sherry vinegar

In the present work, the accelerated ageing process of sherry vinegar has been studied at pilot scale by means of the joint application of ultrasound, micro-oxygenation and wood chips (American oak, French oak and Spanish oak). The CIELab parameters have been studied as well as the polyphenolic and volatile content of the aged vinegar samples. Vinegars aged with American oak presented different chromatic characteristics to those aged with French and Spanish oak and a lower polyphenolic and volatile content than the latter ones. On the other hand, Spanish oak generated vinegars with a higher content of volatile compounds and an intermediate polyphenolic profile between those obtained using French and American oak. In addition, the use of ultrasound for a period between 4 and 21 days, generated vinegars with similar characteristics to others that were aged in the traditional way for between 2 and 6 months. It has been demonstrated that the use of ultrasound, combined with micro-oxygenation and chip addition, is a technique which can accelerate the ageing process of vinegars at a pilot scale, so it could be a viable alternative to obtain sherry vinegars aged in a shorter time.

Flavored Sherry vinegar with citric notes: Characterization and effect of ultrasound in the maceration of orange peels

Accelerated maceration experiments of orange peels in Sherry vinegar employing ultrasounds (US) have been carried out. Their effect on the vinegaŕs volatile composition as well as on its olfactometric and sensory characteristics have been evaluated. The optimal conditions for the ultrasounds were determined as follows: sonication power 550 W/L; pulses 40 s On and 20 s Off; with orange peel 200 g/L established previously. Statistical studies showed that maceration under ultrasounds increased volatile compounds content, since the vinegars obtained showed a high content in alcohols, aldehydes and terpenes. Regarding the olfactometric study, the control vinegar exhibited the lowest values for the “floral”, “greasy” or “citric” categories and the highest value for the “sweet” category, whereas the US macerated vinegars presented the highest and lowest values for the “floral” and the “acid” categories, respectively. Based on their sensory evaluation, the panel members preferred the vinegar where orange peels had macerated under ultrasounds for 90 min. According to the results, ultrasound is a technology that could be employed to broaden the range of products manufactured by Sherry vinegar producers.

Suitability of alternative wood types other than American oak wood for the ageing of Sherry vinegar

The present study has consisted on the monitoring of Sherry vinegar during a whole year ageing in American oak, French oak, Spanish oak and chestnut barrels in order to determine the suitability of alternative wood types other than American oak for the ageing of this type of vinegar. Thirty-two volatile compounds were quantified, CIELab parameters were determined and sensory analyses were carried out during the whole process. The multivariate analysis of the data revealed that the samples that had been aged in Spanish oak barrels were getting more similar to those aged in French oak as the ageing process was progressing. Furthermore, the samples that had been aged in chestnut presented some volatile compounds significantly different from American oak. Finally, although French oak wood transferred the best organoleptic characteristics to Sherry vinegar, Spanish oak and chestnut seemed to be satisfactory alternatives for the ageing process.

Cognitive chaos on spectrofluorometric data to quantitatively unmask adulterations of a PDO vinegar

Different types of intelligent chaotic algorithms have been used for the determination and quantification of adulterants in Sherry vinegar. The product analyzed is one of the most exclusive and high-priced vinegars in the world, with protected designation of origin “Manzanilla-Sanlúcar de Barrameda”, from the Spanish province of Cádiz. It is produced and stored following classic procedures that allow the consumer to enjoy the typical outstanding organoleptic characteristics of this vinegar. Derived from its prestige and price, a spectroscopic tool based on fluorescence has been designed to locate several adulterations including cheap and low-quality vinegars such as those obtained from molasses, rice, cider, and white wine (adulteration range from 1 to 15% in weight). For this purpose, 192 fluorescence spectra from different vinegar samples obtained after irradiating with a laser diode have been analyzed mathematically. The goals established have been to determine the specific type of adulteration as well as their amounts in the prepared mixtures. Among the most outstanding results, it is worth mentioning that the intelligent models can quantify any of the adulterations with relative errors ranging from 1.4 to 7.2%.

Determination of caramel colorants’ by-products in liquid foods by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)

2-Methylimidazole, 4-methylimidazole (2-MI and 4-MI), 2-acetyl-4-(1,2,3,4-tetrahydroxybutyl) imidazole (THI) and 5-hydroxymethylfurfural (5-HMF) are neo-formed compounds generated during the manufacture of caramel colours and are transferred to the processed food. These contaminants are known to have a toxicological profile that may pose health risks. Hence, to characterise THI, 2- and 4-MI and 5-HMF levels in liquid foods, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and sample preparation was divided into two analytical strategies depending on the concentration range expected in the type of foods targeted. For the determination of the imidazole substitutes (THI, 2- and 4-MI), a sample enrichment and clean-up step by strong cation solid-phase extraction was developed. This method is capable of quantifying over a range of 5 ng ml–1 (LOQ) to 500 ng ml–1 with recoveries of 75.4–112.4% and RSDs of 1.5–15%. For determination of 5-HMF, a standard addition method was applied covering the linear range of 0.25–30 µg ml–1 with RSDs from 2.8% (for intraday precision) to 9.2% (for intermediate precision). The validated analytical methods were applied to 28 liquid food samples purchased from local markets. THI was found only in the beer samples at levels up to 141.2 ng ml–1. For 2-MI, non-quantifiable traces were observed for all samples, while 4-MI was observed in all samples with large concentration variations (from < LOQ to 563.9 ng ml–1). 5-HMF was found at expected concentrations, except for a sherry vinegar sample (113 µg ml–1), which required a high level of dilution before following the standard addition protocol.

A survey of biogenic amines in vinegars

This paper reports the determination of biogenic amines by high-performance liquid chromatography (HPLC) and fluorescence detection after derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) in balsamic, apple, and red, white, and Sherry wine vinegars. A solid-phase extraction (SPE) with mixed-mode resins method was used before analysis. The method was successfully validated obtaining adequate values of selectivity, response linearity, precision, accuracy, and low detection and quantification limits. The total content of biogenic amines in vinegars ranged from 23.35 to 1445.2μg/L, being lower than those reported in wines. Putrescine was the amine that showed the highest concentrations in most samples. Methylamine and phenylethylamine were not determined in any vinegar. Balsamic and “Pedro Ximénez” Sherry vinegars reached the highest amounts of biogenic amines, while apple, white and Sherry wine vinegars had the lowest concentrations. Principal component analysis using the biogenic amines as variables, allowed to separate the different kind of vinegars, excepting red vinegars.

Characterization and differentiation of high quality vinegars by stir bar sorptive extraction coupled to gas chromatography-mass spectrometry (SBSE–GC–MS)

A stir bar sorptive extraction gas chromatography–mass spectrometry (SBSE–GC–MS) method has been used for the characterization of the volatile composition of 26 high quality vinegars of three different protected geographical indications (traditional balsamic vinegar of Modena, balsamic vinegar of Modena, and Sherry vinegar). SBSE technique provided the identification of 113 volatile compounds, which belong to different chemical families (short-chain esters, acids, acetates and alcohols, phenols, lactones and benzenic and furanic compounds). 39 volatile compounds were never previously reported in wine vinegars. This characterization contributed to the differentiation of the 100% of the studied samples on the basis of raw material (two different types of wine, and cooked must), aging type (static and dynamic) and aging time (<5 years, between 5 and 25 years, and >25 years). Furanes and terpenes together with acids and alkanes were the most discriminant variables for raw material and aging time, respectively, whereas for aging type, these ones were acetates and esters.

Classification of Sherry vinegars by combining multidimensional fluorescence, parafac and different classification approaches

Sherry vinegar is a much appreciated product from Jerez-Xérès-Sherry, Manzanilla de Sanlúcar and Vinagre de Jerez Protected Designation in southwestern Spain. Its complexity and the extraordinary organoleptic properties are acquired thanks to the method of production followed, the so-called “criaderas y solera” ageing system. Three qualities for Sherry vinegar are considered according to ageing time in oak barrels: “Vinagre de Jerez” (minimum of 6 months), “Reserva” (at least 2 years) and “Gran Reserva” (at least 10 years).In the last few years, there has been an increasing need to develop rapid, inexpensive and effective analytical methods, as well as requiring low sample manipulation for the analysis and characterization of Sherry vinegar. Fluorescence spectroscopy is emerging as a competitive technique for this purpose, since provides in a few seconds an excitation-emission landscape that may be used as a fingerprint of the vinegar.Multi-way analysis, specifically Parallel Factor Analysis (PARAFAC), is a powerful tool for simultaneous determination of fluorescent components, because they extract the most relevant information from the data and allow building robust models. Moreover, the information obtained by PARAFAC can be used to build robust and reliable classification and discrimination models (e.g. by using Support Vector Machines and Partial Least Squares-Discriminant Analysis models).In this context, the aim of this work was to study the possibilities of multi-way fluorescence linked to PARAFAC and to classify the different Sherry vinegars accordingly to their ageing. The results demonstrated that the use of the proposed analytical and chemometric tools are a perfect combination to extract relevant chemical information about the vinegars as well as to classify and discriminate them considering the different ageing.

Chemical Characterization of Commercial Sherry Vinegar Aroma by Headspace Solid-Phase Microextraction and Gas Chromatography−Olfactometry

The sensorial representativeness of the headspace solid-phase microextraction (HS-SPME) aroma extract from commercial Sherry vinegars has been determined by direct gas chromatography-olfactometry (D-GCO). Extracts obtained under optimal conditions were used to characterize the aroma of these vinegars by means of GCO and aroma extract dilution analysis (AEDA). Among the 37 different odorants determined, 13 of them were identified for the first time in Sherry vinegars: 2 pyrazines (3-isopropyl-2-methoxypyrazine, 3-isobutyl-2-methoxypyrazine), 2 sulfur compounds (methanethiol, dimethyl trisulfide), 1 unsaturated ketone (1-octen-3-one), 1 norisoprenoid (β-damascenone), 1 ester (ethyl trans-cinnamate) and 6 aldehydes (2- and 3-methylbutanal, octanal, nonanal, (E)-2-nonenal and (E,E)-2,4-decadienal). The determination of the odor thresholds in a hydroacetic solution together with the quantitative analysis-which was also performed using the simple and fast SPME technique-allowed obtaining the odor activity values (OAV) of the aromatic compounds found. Thus, a first pattern of their sensory importance on commercial Sherry vinegar aroma was provided.

Characterization of Vitis vinifera L. subspecies sylvestris (Gmelin) Hegi in the Ebro river Basin (Spain)

A wild grapevine population of 76 vines of Vitis vinifera L. subspecies sylvestris (Gmelin) Hegi was found along the Iregua river valley (Northeastern Spain), located in the Iberica mountain-range. The characterization of this phytogenetic resource was based on an ampelographic description of the male and female individuals and an evaluation of their sanitary state. This shows that the imported North American downy and powdery mildews are the main pathogens, but no symptoms caused by phylloxera on roots were found. Different degrees of infestation caused by Eryophid mites, Colomerus vitis and Calipitrimerus vitis , were also registered on leaves. On the other hand, the red wines obtained show an alcoholic degree situated between 8.5 and 10.8, pH around 3.5 and a high intensity of colour, between 10.2 and, 11.3. The vinegar had only 3.5° of acetic acid. Its phenolic composition is similar to those reported from red and Sherry vinegars produced from cultivars. The genetic analysis based on 18 samples, using 16 nuclear microsatellites, shows a low genetic diversity (He = 0.45). This might be due to inbreeding caused by mating among siblings in this isolated population. The genetic comparison with the allowed cultivars of this Guarantee of Origin showed two distinct gene pools. So it indicated that there is no genetic contribution of these native vines to current instead of actual local varieties. It is necessary to preserve this phytogenetic resource to be used in breeding programs and to restore its destructed habitats by human different impacts.

Gas Chromatography−Mass Spectrometry (GC−MS) Characterization of Volatile Compounds in Quality Vinegars with Protected European Geographical Indication

The volatile composition of 26 premium quality vinegars belonging to three different protected geographical indications (traditional balsamic vinegar of Modena, balsamic vinegar of Modena, and sherry vinegar) has been characterized by means of a solid-phase extraction (SPE) gas chromatography-mass spectrometry GC-MS method. Among the about 90 quantified compounds, short-chain fatty acids, furanic compounds, enolic derivatives, and some esters were found to discriminate the samples as a consequence of differences in the extent of Maillard reactions, presence of alcoholic fermentation, or duration of wood aging.

Defining the Typical Aroma of Sherry Vinegar: Sensory and Chemical Approach

The aroma of the three different classes of Sherry vinegar was evaluated by gas chromatography/mass spectrometry (GC-MS) and gas chromatography/olfactometry (GC-O). GC-O was employed to identify substances responsible for aromatic notes associated with the selected descriptors of the typical aroma of Sherry vinegar and odor activity values (OAV) calculated to measure the single impact effect of different compounds selected by GC-O. Diacetyl, isoamyl acetate, ethyl isobutyrate, isovaleric acid, sotolon, and ethyl acetate reached high OAVs, turning out to be characteristic odor active compounds in Sherry vinegars. A total of 58 compounds were quantified, among them, 7 had not been previously reported in Sherry wine vinegars: ethyl 2-methylbutyrate, ethyl heptanoate, ethyl furoate, and ethyl benzoate, acetophenone, nonanoic acid, and sotolon. Linear discriminant analysis (LDA) reveals that using aroma compounds as variables, we can classify Sherry vinegars with 100% correct scores as different from red wine vinegars.

Targeting Key Aromatic Substances on the Typical Aroma of Sherry Vinegar

Two gas chromatography-olfactometry (GC-O) techniques were used to screen targeting compounds with an impact on the perceived quality of Sherry vinegar: detection frequency and aroma extract dilution analysis (AEDA). The GC-O study revealed the presence of 108 aromatic notes, of which 64 were identified. Diacetyl, isoamyl acetate, acetic acid, and sotolon reached the highest frequency and flavor dilution (FD) factors. Ethyl acetate accounted for the maximum frequency but only a FD factor of 4. To test the sensory impact of these odorants, they were added to a 7% (w/v) acetic acid solution. We determined similarity values (SV) between solutions and the Sherry vinegar. The highest value from the similarity test was observed when diacetyl, ethyl acetate, and sotolon were added simultaneously. The profile of this model solution and a representative Sherry vinegar showed good similarity in the general impression descriptor, which emphasizes the important contribution of these three compounds to the global aroma of this vinegar.

Sensory Evaluation of Sherry Vinegar: Traditional Compared to Accelerated Aging With Oak Chips

The aim of this work was to describe the sensory profile of wine vinegars aged with oak chips (accelerated aging) compared with those elaborated by a traditional method (sherry vinegar). Two types of oak chips (American and French) were used to perform sample infusions. The chips were subjected to toasting to simulate the heating effect during oak board bending in cask construction. Ten sensory parameters were selected to describe the vinegars with 11 trained panelists. Sensory profiles were compared and sensorial differences observed among the samples analyzed. These differences are largely associated with the pungent sensation rather than the sensory attributes generated from the oak wood.