Inferring the origin of rare fruit distillates from compositional data using multivariate statistical analyses and the identification of new flavour constituents

Overview of the distinctive characteristics of strawberry, raspberry, and blueberry in berries, berry wines, and berry spirits

Red berries have gained popularity as functional and nutritious food due to their health benefits, leading to increased consumer demand and higher production, totaling over 11,000 ktons for strawberries, raspberries, and blueberries combined in 2021. Nutritionally, strawberries, raspberries, and blueberries present high levels of vitamin C (9.7-58.8 mg/100 g dry weight [dw]), folates (6-24 µg/100 g dw), and minerals (96-228 mg/100 g dw). Due to their perishable nature, producers have utilized alcoholic fermentation to extend their shelf life, not only increasing the lifespan of red berries but also attracting consumers through the production of novel beverages. Strawberry, blueberry, and raspberry wines possess low alcohol (5.5-11.1% v/v), high acidity (3.2-17.6 g/L), and interesting bioactive molecules such as phenolic compounds, carotenoids, polysaccharides, and melatonin. Distillation holds tremendous potential for reducing food waste by creating red berry spirits of exceptional quality. Although research on red berry spirits is still in the early stages, future studies should focus on their production and characterization. By incorporating these factors, the production chain would become more sustainable, profitable, and efficient by reducing food waste, capitalizing on consumer acceptance, and leveraging the natural health-promoting characteristics of these products. Therefore, this review aims to provide a comprehensive overview of the characteristics of strawberry, blueberry, and red raspberry in berries, wines, and spirits, with a focus on their chemical composition and production methods.

Alcoholic Fermentation as a Source of Congeners in Fruit Spirits

Fermentation is a crucial process in the production of alcoholic beverages such as spirits, which produces a number of volatile compounds due to the metabolic activities of yeast. These volatile compounds, together with the volatile components of the raw materials and the volatile compounds produced during the distillation and aging process, play a crucial role in determining the final flavor and aroma of spirits. In this manuscript, we provide a comprehensive overview of yeast fermentation and the volatile compounds produced during alcoholic fermentation. We will establish a link between the microbiome and volatile compounds during alcoholic fermentation and describe the various factors that influence volatile compound production, including yeast strain, temperature, pH, and nutrient availability. We will also discuss the effects of these volatile compounds on the sensory properties of spirits and describe the major aroma compounds in these alcoholic beverages.

Volatile Constituents of Some Selected Plant Species Traditionally Used as Tea in the Sharri Mountains (Kosovo)

The study evaluates the chemical composition of the volatile constituents of ten plant species traditionally used as herbal tea in the Sharri Mountain regions (Kosovo and North Macedonia). Volatile constituents responsible for the flavour and fragrance of selected species (Crataegus monogyna, Cydonia oblonga, Malus sylvestris, Matricaria chamomilla, Morus alba, Morus nigra, Rosa canina, Sambucus nigra, Tilia cordata, and Vaccinium myrtillus) were separated and then identified using GC-MS, whereas GC-FID is employed for the quantitative analysis. Experimental data revealed different patterns of volatile constituents depending on plant species. Monoterpenes, sesquiterpenes, diterpenes, and norisoprenoids were the most abundant volatile constituents. Principal component analysis (PCA) was deployed for data analysis and resulted in grouping these ten species in four principal clusters. The combination of various volatile constituents present in specific plant species may play an important role in the specific aroma and taste sensation of these species used as recreational teas.

Essential oil characterization of Prunus spinosa L., Salvia officinalis L., Eucalyptus globulus L., Melissa officinalis L. and Mentha x piperita L. by a volatolomic approach

In this study a volatolomic approach is proposed for the characterization of the volatile organic compound (VOC) composition of essential oils (EOs) extracted from common aromatic plants. Five species (Prunus spinosa L., Salvia officinalis L., Eucalyptus globulus L., Melissa officinalis L. and Mentha x piperita L.), particularly widespread in Southern Italy, were selected as recognized sources of natural bioactive compounds with beneficial properties. Hydro distillation and solid-liquid extraction with ethanol at different percentages were used to obtain EOs, and their extraction capabilities were compared analyzing chromatographic profiles obtained by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography - mass spectrometry (GC-MS). The analytical procedure was optimized in term of SPME fiber, adsorption time and desorption time. GC-MS analyses were performed allowing the profiling of the VOC fingerprint in each plant extract. Experimental data were processed by a statistical multivariate approach (Analysis of Variance and Principal Component Analysis obtained for compounds and chemical classes), confirming that EO aroma profiles were statistically different for each of the selected five plants. The proposed volatolomic approach has proved to be an easy and efficient tool to study the aroma profile, allowing the collection of specific information and opening new perspectives and opportunities for the detection and identification of VOCs in agricultural and ecological applications.

Identification, quantitation and sensorial contribution of lactones in brandies between China and France

Lactones are important flavor compounds in lots of foodstuffs. They also play an important role in brandy, but have not been studied at large. In this study, solid-phase extraction (SPE) and stir bar sorptive extraction (SBSE) combined with comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry (GC × GC-TOFMS) were applied to identify and quantify lactones in brandies between China and France. Totally 17 lactones were identified, four of which were detected only in SBSE. Among them, γ-valerolactone, γ-heptalactone, δ-octalactone, γ-undecanolactone and δ-dodecalactone were detected in brandy for the first time. The results of partial least squares-discriminant analysis (PLS-DA) revealed that lactones distinguished regional characteristics among different brandies. The omission test showed that four lactones (OAV > 1) had direct impact on the aroma of brandy, and other seven lactones at sub-threshold (0.1 < OAV < 1) provided peach and apricot aroma characteristics through synergistic effects.

Quantitation, Organoleptic Contribution, and Potential Origin of Diethyl Acetals Formed from Various Aldehydes in Cognac

Cognac wine distillate (WD), especially that produced during aging, is marked by complex and elegant aroma. This work aimed at expanding the knowledge on the Cognac WD aroma by a sensory-guided approach, involving a fractional-distillation technique and gas chromatography coupled to olfactometry and mass spectrometry (GC-O-MS). In doing so, a fruity-odor zone was highlighted in WD extracts that was attributed to the diethyl acetal family. Ten additional diethyl acetals were detected by GC-MS. Next, an assay method was developed and validated for seven of these diethyl acetals. Their detection thresholds were evaluated in a model solution of water/ethanol (60:40, v/v). 1,1-Diethoxy-3-methylbutane was shown to present a significant organoleptic impact because its olfactory-detection threshold (323 μg/L) is lower than its range of concentrations in WD (461 to 3337 μg/L). Given that diethyl acetals result from reactions between ethanol and aldehydes, quantitative correlations between diethyl acetals and corresponding aldehydes were considered.