Production method and varietal source influence the volatile profiles of spirits prepared from fig fruits (Ficus carica L.)

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.

Figs (Ficus carica L.) Used as Raw Material for Obtaining Alcoholic Fermented Beverages

The fig tree is one of the oldest species cultivated by mankind. In spite of having high nutraceutical value and a pleasant taste, the fig is not a widely cultivated fruit. Furthermore, figs are extremely perishable, therefore they are usually sold as dried fruits rather than fresh. To harness this valuable fruit, other derived products should also be considered. For instance, the production of alcoholic beverages fermented from figs comes in response to the interest of producers to capitalize on these fruits in other ways than as fresh or dried fruit or jam. The present research focuses on the possibility of obtaining marketable fermented beverages made from three fig varieties cultivated in southwestern Romania. The aim of the study was to provide an optimized technological process for the production of alcoholic beverages fermented from fresh figs and to assess their quality and acceptability. The products were obtained in triplicate from each fig variety and their quality was assessed by determining their main chemical parameters, as well as their sensory properties. This research provided valuable information regarding the technological process to be applied for fig fermented beverages, processes which can still be further refined to better meet the consumer demand.

Influence of elaboration process on chemical, biological, and sensory characteristics of European pennyroyal liqueurs

BACKGROUND

Mentha pulegium is an aromatic and medicinal plant used in different Mediterranean herb-based liqueurs, whose phytochemical composition depends on the elaboration technique used. The aim of this work was to investigate differences in the sensory, chemical, and biological characteristics of pennyroyal liqueurs elaborated by hydro-alcoholic (HI) and aqueous (AI) infusions, percolation (P), maceration (M), and distillation (D) techniques, and by the mixture of spirit with pennyroyal essential oil (EO). The volatile composition determined by gas chromatography-mass spectrometry (GC-MS) and gas chromatography coupled to flame ionization detection (GC-FID), the total phenolic (TPC) and flavonoid (TFC) contents, the antioxidant (AC), and enzyme (α-glucosidase, tyrosinase, and acetylcholinesterase) inhibitory capacities, and the sensory analysis by napping, were evaluated in the liqueurs obtained.

RESULTS

Monoterpenes and sesquiterpenes were the main volatiles present in liqueurs. The M, P, HI, and AI liqueurs showed the highest TPC, TFC, and AC values; and pulegone, the main hepatotoxic chemotype, was found in concentrations that gave rise to concern. The D and EO liqueurs stand out for their acceptable pulegone content and greater tyrosinase inhibition. Similar liqueur classifications were achieved by sensory analyses, and physico-chemical and biological analyses using multiple factor and principal component analyses, respectively.

CONCLUSION

These results are an important contribution to the identification of the most appropriate elaboration conditions for herbal liqueurs with the healthiest chemical composition and functional properties. © 2020 Society of Chemical Industry.

Comparative Study of Fig Volatile Compounds Using Headspace Solid-Phase Microextraction-Gas Chromatography/Mass Spectrometry: Effects of Cultivars and Ripening Stages

Aroma is one of the essential parameters that determine fruit quality. It is also an important feature of varietal characterization and so valuable for agro-biodiversity identification and preservation. In order to characterize changes in the aroma fingerprint through fig development, the main objective of the present research was to study the volatile organic compound (VOC) profiles of figs (Ficus carica L.) from three cultivars, Taamriwthe (TH), Azegzaw (AZ), and Averkane (AV), at three ripening stages (unripe, ripe, and fully ripe). Analyses was performed using Headspace Solid-phase Microextraction and gas chromatography coupled with mass spectrometry. Results revealed the presence of 29 compounds that were grouped into different chemical classes. Aldehydes comprised the most abundant VOCs identified in all the studied figs, while alcohols, ketones, and terpenes comprised the minor compounds found in TH, AZ, and AV figs, respectively. Different aroma descriptors were identified throughout the ripening stages of figs; fruity and green aromas were dominant in all cultivars, while a fatty aroma scarcely occurred in figs. A gallery plot representation demonstrated that certain VOCs differentiate the studied cultivars and the different ripening stages of figs. Principal component analysis findings demonstrated characteristic VOCs of distinct ripening stages and cultivars, those VOCs can be used as fingerprints to distinguish different cultivars and/or ripening stages.

Influence of extraction solvents on the polyphenol contents, compositions, and antioxidant capacities of fig (Ficus carica L.) seeds

Fig seeds are considered to be significantly responsible for the bioactive compounds of fig. In this study, the effects of six different solvents (100% acetone, 100% methanol, 100% ethanol, 50% (v/v) aqueous acetone, 50% (v/v) aqueous methanol and 50% (v/v) aqueous ethanol) with changing polarities on the polyphenol contents and antioxidant capacities of fig seed extracts were investigated. Total polyphenol contents (TPCs), total flavonoid contents (TFCs), antioxidant capacities (DPPH and FRAP assays) and polyphenol compositions of the extracts were evaluated. The results indicated that fig seeds extracted by 50% (v/v) aqueous methanol exhibited the highest TPC (714 mg GAE/kg DM), TFC (312 mg (+)-CE/kg DM), DPPH (41.6%) and FRAP (8504 mg FeSO4/kg DM) values. Also, same extract had the maximum values of chlorogenic acid (131.9 mg/kg DM), (-)-epicatechin (166.4 mg/kg DM) and rutin (50.7 mg/kg DM) (p<0.05). The extractability of syringic acid was determined to be highest with 50% aqueous methanol (8.03 mg/kg DM) and 50% aqueous ethanol (8.13 mg/kg DM) (p>0.05). The psoralen extractability was highest in 50% aqueous acetone (53.0 mg/kg DM) and 50% aqueous ethanol (54.0 mg/kg DM) (p>0.05). High correlations among TPCs, TFCs, antioxidant capacities and individual polyphenols of fig seed extracts were also observed.

A case study comparing distillation technologies for plum palinka production

Palinka production has a long tradition in Hungary and the neighboring countries. Previously, the fruit distillate was produced exclusively using the traditional Pot-Still Double Distillation (PSDD) technology. This distillation method means, in practice, a simple fractional distillation repeated twice. However, in other industries, such as the petroleum industry or the pharmaceutical industry, a continuous, so-called repeated distillation procedure is used (RCDS – Rectification Column Distillation Systems). In the production of palinka, the latter procedure has gained more and more ground in recent years, thus displacing the traditional technology. In the territory of today’s Hungary, there are more than 16,000 registered private palinka distillers. However, based on public databases, it is not possible to know the proportion of the two different palinka making processes used in palinka production. The two processes differ to a large degree. The amount of hearts obtained using the continuous operation plate rectification column (RCDS) is lower, while its alcohol content is very high: 75 – 90 vol%, depending on the fruit. On the other hand, when using the traditional pot-still double distillation (PSDD) method, the amount of hearts is higher, but its alcohol content is lower (60 – 70%). The continuous procedure, also called single-stage, is faster. This is one of the reasons for its popularity because it makes production more economical. The objective of our research was to find out whether a significant difference could be detected between the two plum palinkas produced using the two different distillation technologies, based on current legal requirements. Our research also included sensory testing to determine whether consumers could distinguish between the products manufactured in different ways. Our analyses were carried out in 2019 in the accredited laboratory of the National Food Chain Safety Office and among the students and staff of the Gödöllő campus of Szent István University.

Volatile and phenolic profiles of traditional Romanian apple brandy after rapid ageing with different wood chips

The aim of this work was to find differences in the volatile and phenolic profiles of the traditional Romanian apple brandy pălinca aged with various species of wood chips. Seven types of wood species, two types of oak (Quercus petraea and Quercus robur), plus sweet chestnut, mulberry, walnut, fir and cherry, were considered. The majority of volatile compounds characterizing the aroma profile of pălinca were esters, particularly ethyl esters, with ethyl isobutyrate, ethyl isovalerate, ethyl caproate, ethyl octanoate and ethyl decanoate as the most abundant. The most important source of catechin was cherry wood. Rutin and juglone were solubilised only in walnut wood aged brandy. Vanillin, increased significantly in chestnut aged apple brandy. Given the cost and difficulty in handling wooden barrels, and as an alternative being able to select from a range of specific wooden chips, this work could potentially guide actors in beverage industry to less expensive alternatives.

Nutritional, chemical and bioactive profiles of different parts of a Portuguese common fig (Ficus carica L.) variety

This study aims to give an unprecedented contribution on the chemical composition and bioactivities of the most produced and appreciated Portuguese fig variety ("Pingo de Mel") with the view of expanding the knowledge on its potentialities. An advanced characterization of its peel and pulp parts was carried out. Four free sugars (glucose, fructose, trehalose and sucrose), 5 organic acids (oxalic, quinic, malic, citric, and succinic acids), tocopherols in all their 4 forms, besides 23 fatty acids were detected in the samples. Fifteen different phenolic components were found in the peel hydroethanolic extract; whereas 12 were detected in the pulp hydroethanolic extract. Quercetin-3-O-rutinoside (rutin) was the major constituent of the peel, accounting for 33.8% of its phenolic content, followed by 5-O-caffeoylquinic acid and vanillic acid malonyl di-deoxyhexoside. Caffeic acid derivatives, such as caffeic acid hexosides, were the major components of pulp, followed by vanillic acid derivatives and O-caffeoylquinic acid. Both extracts displayed promising antioxidant capacities in all methods used, namely the 2,2-diphenyl-1-picrylhydrazyl radical-scavenging, the reducing power, the inhibition of β-carotene bleaching assays, the thiobarbituric acid reactive substances assay and the oxidative haemolysis inhibition assay; however, the peel presented significantly lower IC₅₀ values than pulp. The extracts showed practically identical antibacterial capacities, being effective against methicillin-sensitive Staphylococcus aureus (MICs = 2.5 mg/mL), besides methicillin-resistant S. aureus, Escherichia coli and Morganella morganii (MICs = 5 mg/mL). The obtained results evidence that the fig peel is superior to the corresponding pulp as it relates to nutritional and phenolic profiles as well as bioactivities, endorsing the urgency in valorising and exploiting this usually discarded industrial by-product.