Phenolic compounds and aroma‐impact odorants in herb liqueurs elaborated by maceration of aromatic and medicinal plants in grape marc distillates

Fresh Basil Infusion: Effect of Sous-Vide Heat Treatment on Their Volatile Composition Profile, Sensory Profile, and Color

Herbs, including basil, are used to enhance the flavor of food products around the world. Its potential is influenced by the quality of fresh herbs and processing practices, wherein conditions of heat treatment play an important role. The aim of the research was to determine the effect of sous-vide heat treatment on the volatile compounds profile, sensory quality, and color of basil infusions. The material used for research was aqueous basil infusion prepared conventionally at 100 °C, and using the sous-vide method (65, 75, and 85 °C). The composition of volatile compounds was identified by GC/MS analysis, the sensory profile was assessed using a group of trained panelists, while the color was instrumentally assessed in the CIE Lab system. No significant differences were found in the intensity of the taste and aroma of basil infusions at different temperatures. Seventy headspace volatile compounds were identified in the analyzed samples, ten of which exceeded 2% of relative area percentage. The most abundant compounds were eucalyptol (27.1%), trans-ocimene (11.0%), β-linalool (9.2%), and β-myrcene (6.7%). Most of the identified compounds belonged to the terpenes and alcohols groups. Our findings show that the conventional herbal infusion was more like a sous-vide infusion prepared at the lowest temperature SV65, while SV75 and SV85 were similar to each other but different from the conventional. However, a smaller number of volatile compounds in the samples heated at higher temperatures of sous-vide were identified. The sous-vide samples showed a higher content of alkanes. The sous-vide method (p ≤ 0.05) resulted in darker, less green, and less yellow basil leaves than fresh and traditionally steeped ones. Long heat treatment under vacuum at higher temperatures causes a pronounced change in the aroma composition.

Shading of Medical Plants Affects the Phytochemical Quality of Herbal Extracts

The manipulation of light intensity by shade nets can lead to exchanges in the phytochemical quality and antioxidants ofsome herbs. This study aimed to determine whether shading by pearl nets (50% shade index) could improve the bioactive compounds in several medicinal herbs such as thyme (Thymus vulgaris L.), marjoram (Origanum majorana L.), oregano (Origanum vulgare L.), lemon balm (Melissa officinalis L.), and peppermint (Mentha piperita L.), and their correspondingherbal extracts during a four-week maceration process in ethanol. Oregano and thyme provided the highest yield of total extractive substances (TES) from both shaded and non-shaded plants. Among all studied herbs, the highest level of antioxidants, expressed as total phenolic content (TPC) was found in extracts from shaded plants of lemon balm. Herbal extracts produced from non-shaded thyme and marjoram had higher flavonoid contents compared to herbal extracts from shaded plants. Accumulation of the investigated secondary metabolites depends more on the specificity of a plant species rather than light intensity. This study was an initial step in the production of medicinal plants with an increased quantity of antioxidant and other bioactive compounds during the maceration process in extracts, aimed to be used as natural alcoholic productwith added value.

Chemical characterization of eight herbal liqueurs by means of liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry

Herbal liqueurs are a large group of diverse alcoholic beverages with an ancient tradition produced by maceration of various herbs and spices and are commonly drunken before or after a meal to aid in the digestion because of their potential functional properties. In the presented work, eight different commercial herbal liqueurs were investigated with regard to their composition of phenolic compounds by liquid chromatography ion mobility quadrupole time-of-flight mass spectrometry (LC-IM-QTOF-MS). This multidimensional analytical platform uses all-ion fragmentation for a deep coverage of the foodome. After an extensive data clean-up, 3225 features were found. 213 features were manually annotated due to the absence of databases and software tools able to consider the drift time or Collison Cross Section (CCS) together with high resolution MS/MS spectra for identification. The identified compounds reflected the large variance between the investigated samples and a wealth of potential bioactive compounds that these liqueurs harbor.

Quantitative Descriptive Analysis of Traditional Herbal and Coffee Liqueurs made with Grape Marc Spirit (Orujo)

Orujo is a recognized traditional grape marc distillate from Galicia (NW of Spain). It is also employed as an alcohol base to elaborate coffee and herbal liqueurs and spirits. In this manuscript, quantitative descriptive analysis was applied to obtain the most important sensory terms that describe these traditional beverages. Thirteen trained panelists developed a complete sensory lexicon. Sixteen sensory descriptors (four in appearance, five in aroma, four in mouth, and three in aftertaste) were defined, valuated, and scored with the corresponding references, after elimination of hedonic, synonymous, and non-pertinent attributes according to statistical methods. The panelists evaluated a total of 464 samples in order to define their sensory profile. Panel performance was investigated showing good discriminatory ability, repeatability, and reproducibility. Principal Component Analysis (PCA) was also applied to identify the sensory descriptors that better discriminate the samples. The results obtained showed the importance of including new terms (orujo, chocolate-cocoa, floral, bitter, and astringent) in the tasting sheet, mainly in the case of coffee liqueurs to improve their sensory profile. The results of this study were useful for the development and implementation of an important tool for the corresponding regulating council in the sensory characterization and qualification of Galician liqueurs.

Physicochemical and aromatic characterization of carob macerates produced by different maceration conditions

Carob liqueur is an alcoholic drink (minimum 15% v/v of ethanol and 100 g/L of sugar) typical for the Mediterranean countries. In the current work, carob macerate produced by maceration of carob pods in hydroalcoholic base at different maceration conditions was characterized for the first time based on its aroma compounds/profile, physicochemical parameters, and chromatic characteristics. The results confirm the migration process of bioactive compounds, aroma compounds, and sugars flowing from the carob pod to the hydroalcoholic base. Changes in ethanol concentration modify the physical properties of the solvent and influence the phenolic and aroma compounds extraction, color, and acidity of the obtained samples. The higher content of phenolic compounds was determinate in the samples obtained in the darkness. The amounts of phenols were in the range of some red fruit liqueurs or walnut liqueurs, and sugars (mostly sucrose) ranging between 96 and 107 g/L. Twenty-six (out of total 94) aroma compounds were detected in all samples, of which 17 esters, 3 alcohols, 4 ketones, and 2 acids. Low molecular weight ethyl esters, ethyl hexanoate, ethyl 2-methyl propanoate, ethyl octanoate, ethyl benzoate, ethyl butanoate, and ethyl cinnamate, were the most abundant. Carob pod maceration in 50% v/v hydroalcoholic base (1:5 solid to liquid ratio) in darkness at room temperature during 8 weeks can be recommended as optimal maceration conditions for production of the aromatic carob macerate with functional properties.

Changes in beneficial bioactive compounds in eight traditional herbal liqueurs during a one-month maceration process

BACKGROUND

Herbs are rich in various beneficial bioactive compounds and they can be used for many different purposes. One of the most common is maceration of herbs in alcohol. Different substances respond differently to extraction in prepared solutions. It is very important to enhance the highest proportion of beneficial ingredients during the maceration process in a herbal liqueur. A comparative analysis of numerous different phenolic compounds from eight of the most frequently used herbs for making aperitifs in Europe was performed.

RESULTS

In the comparison among all studied herbs, the highest phenolic content was found with Artemisia absinthium (wormwood) (14.61 mg g^-1 ) and Mentha piperita (peppermint) (13.89 mg g^-1 ), while the lowest content was found with Centaurium erythraea (common centaury) (3.96 mg g^-1 ). Salvianolic acid isomers and caffeic acid derivatives were the greatest contributors to the total phenolic content in lemon balm, wormwood, peppermint, fennel and sage. These compounds contain more hydroxyl groups and they were better extracted at the beginning of the maceration process. Caraway and common centaury contain more flavonols (quercetin and kaempferol derivatives), with higher chemical stability and fewer hydroxyl groups in their structure.

CONCLUSION

The compositions of eight herbal liqueurs were highly related to the presence of different herbal ingredients and their solubility in the extract over time. Most flavonol derivatives were extracted over a longer time and the two liqueurs (common centaury and caraway) therefore had the highest phenolic contents after 3 weeks of maceration. © 2019 Society of Chemical Industry.