Exploiting by-products from the oenological industry to extract antioxidant chemicals is a shared goal that combines the need to reduce the wine sector’s environmental impact with the need to improve the availability of these biomolecules, according to a circular economy approach. Natural deep eutectic solvents (NaDES) have recently captured researchers’ interest as a safer and more environmentally friendly alternative to traditional solvents due to their effectiveness, low toxicity, and stability. In this work, we set out to investigate several NaDES for the extraction of phenolic chemicals from local monovarietal grape pomace resulting from different vinification procedures (including both red and rosé vinification of Negroamaro and Primitivo grapes; rosé vinification of Susumaniello grapes and white vinification of Chardonnay, Fiano and Malvasia bianca grapes), with the additional goal of generalizing the use of NaDES to extract chemicals of interest from organisms selected from the wide plant biodiversity. Three binary choline chloride-based NaDES (DES-Lac, DES-Tar, and DES-Gly, with lactic acid, tartaric acid, and glycerol as hydrogen bond donors, respectively) were compared to ethanol as a conventional solvent, and the extracts were evaluated using HPLC/MS and colorimetric techniques. The results revealed that each NaDES produces a substantially higher total phenolic yield than ethanol (up to 127.8 mg/g DW from Primitivo rosé grape pomace). DES-Lac and DES-Tar were more effective for anthocyanins extraction; the most abundant compound was malvidin 3-O-glucoside (highest extraction yield with DES-Lac from Susumaniello pomace: 29.4 mg/g DW). Regarding phenolic compounds, DES-Gly was the most effective NaDES producing results comparable to ethanol. Unexpectedly, Chardonnay pomace has the greatest content of astilbin. In most cases, grape pomace extracts obtained by rosé and white vinification provided the maximum yield. As a result, NaDES have emerged as a viable alternative to traditional organic solvent extraction techniques, allowing for higher (or equal) yields while significantly lowering costs, hazards, and environmental impact.

Natural deep eutectic solvents (NaDESs) are emerging solvents for their yield when used for extraction of different molecules, including polyphenols. NaDESs are a cutting-edge technology that offers numerous advantages, including cheap cost, safety, effectiveness and environmental friendliness. However, due to NaDES’ high boiling point, the recovery and separation of compounds after the extraction is the bottleneck of the process. In this work, two affordable methods were tested for the recovery of phenolic compounds from three binary NaDESs (composed of choline chloride mixed separately with lactic acid, tartaric acid or glycerol as hydrogen bond donors): the antisolvent and the liquid–liquid extraction methods. The former was assessed by diluting the extracts with different aliquots of water, employed as antisolvent, which was ineffective. For the liquid–liquid extraction method, ethyl acetate (EtOAc), acetonitrile (ACN), 2-chlorobutane (2-CB) and 2-methyltetrahydrofuran (2-MeTHF) were compared. Except for ACN, all solvents were perfectly immiscible with the three NaDESs, forming biphasic systems that were analyzed by colorimetric assays and HPLC/MS. 2-MeTHF applied on a 10-fold water dilution of the NaDES extract reached recovery percentages higher than 90% for most of the non-anthocyanin phenols and good recovery (up to 80%) for some anthocyanins. 2-MeTHF appears to be the first known solvent capable of extracting anthocyanins from NaDESs. Finally, a two-step liquid–liquid extraction performed firstly with EtOAc and subsequently with 2-MeTHF is proposed for the separation of different phenolic fractions.

While studying aromas produced by the edible flowers of Tulbaghia violacea, we noticed a different production of (Z)-3-Hexenyl acetate (a green-leaf volatile, GLV) by purple (var. ‘Violacea’) and white (var. ‘Alba’) flowers. The white Tulbaghia flowers constantly emits (Z)-3-Hexenyl acetate, which is instead produced in a lower amount by the purple-flowered variety. Thus, we moved to analyze the production of (Z)-3-Hexenyl acetate by whole plants of the two varieties by keeping them confined under a glass bell for 5 h together with a SPME (Solid Phase Micro Extraction) fiber. Results show that six main volatile compounds are emitted by T. violacea plants: (Z)-3-Hexenyl acetate, benzyl alcohol, nonanal, decanal, (Z)-3-Hexenyl-α-methylbutyrate, and one unknown compound. By cutting at half-height of the leaves, the (Z)-3-Hexenyl acetate is emitted in high quantities from both varieties, while the production of (Z)-3-Hexenyl-α-methylbutyrate increases. (Z)-3-Hexenyl acetate is a GLV capable of stimulating plant defenses, attracting herbivores and their natural enemies, and it is also involved in plant-to-plant communication and defense priming. Thus, T. violacea could represent a useful model for the study of GLVs production and a ‘signal’ plant capable of stimulating natural defenses in the neighboring plants.

In recent decades, the food production chain has undergone transformations that have profoundly affected the way food is supplied, causing changes in the quality of the final products. Moreover, biodiversity is seriously threatened worldwide, and the valorization of local germplasm is a priority goal for most sectorial policies in Europe and elsewhere. Southern Italy and the Mediterranean basin present a vast heritage of fruit tree cultivars that is gradually being lost. Through this work, we aim to valorize a well-adapted local pear cultivar named Petrucina from the Salento area (southeastern Italy, Apulia region), which has never been studied before in detail. With this aim, the nutritional and nutraceutical features of pear flesh were characterized and compared with a reference pear cultivar that is widespread and well-known in Europe (cv. ‘Conference’). Petrucina fruits have shown a peculiar aromatic compound profile, and a content of up to 398.3, 30.9, and 4.7 mg/100 g FW of malic acid, citric acid, and ascorbic acid, respectively, much higher than that of Conference fruits. Additionally, Petrucina flesh presents a more than triple total phenolic content and an antioxidant activity more than double that of Conference, making Petrucina a true functional food that deserves wide appreciation.

With the intention of investigating in further depth the horticultural biodiversity resulting from the selection and conservation effort carried out by farmers (custodians) who are dedicated to growing traditional products, we focused on six local landraces of Brassica rapa L. subsp. sylvestris (L.) Janch.; we conducted analyses addressing the presence of glucosinolates (GLSs), phenolic compounds and the antioxidant capacity of extracts of B. rapa landraces belonging to three groups with different growth phase behavior from planting to inflorescence appearance in the Salento area (Puglia or Apulia region, Italy). The studies focused on three local landraces known by Salento farmers as cima di rapa cinquantina (two separate accessions, 50SC and 50SD), cima di rapa sessantina (accessions 60SC and 60SD) and rapacaula (accessions rcSD and rcGA). We revealed the presence of eleven different glucosinolates and three main flavonoids, such as kaempferol, quercetin and isorhamnetin derivatives. The distribution and content of glucosinolates and flavonoids varied widely among the different landraces. Glucobrassicanapin was the predominant compound in all landraces, followed by gluconapin, except for 60SC, where the main GLS was the indolic glucobrassicin. Moreover, 50SC, 50SD and 60SC are characterized by the highest flavonoid content and the highest antioxidant capacity. The findings provide the basis for the characterization of B. rapa subsp. sylvestris L. local landraces as a useful source of valuable metabolites for human health, as well as for identifying one landrace with higher nutritional value as a starting point for accession conservation and economic development.