Color, phenolic content, and chemical age values of red wines made from Cretan grape varieties (Kotsifali, Mandilari) were evaluated over nine months of maturation in different containers for two vintages. The wines differed greatly on their anthocyanin profiles. Mid-IR spectra were also recorded with the use of a Fourier Transform Infrared Spectrophotometer in ZnSe disk mode. Analysis of Variance was used to explore the parameter’s dependency on time. Determination models were developed for the chemical age indexes using Partial Least Squares (PLS) (TQ Analyst software) considering the spectral region 1830–1500 cm⁻¹. The correlation coefficients (r) for chemical age index i were 0.86 for Kotsifali (Root Mean Square Error of Calibration (RMSEC) = 0.067, Root Mean Square Error of Prediction (RMSEP) = 0,115, and Root Mean Square Error of Validation (RMSECV) = 0.164) and 0.90 for Mandilari (RMSEC = 0.050, RMSEP = 0.040, and RMSECV = 0.089). For chemical age index ii the correlation coefficients (r) were 0.86 and 0.97 for Kotsifali (RMSEC 0.044, RMSEP = 0.087, and RMSECV = 0.214) and Mandilari (RMSEC = 0.024, RMSEP = 0.033, and RMSECV = 0.078), respectively. The proposed method is simpler, less time consuming, and more economical and does not require chemical reagents.

The production of raisins, a method of grape preservation since antiquity, has evolved with various drying techniques that significantly impact the quality and safety of the final product. This study evaluates the efficacy of a solar indirect dryer compared to traditional sun-drying methods for drying Centennial Seedless and Sultanina grape cultivars in Crete, Greece. Key parameters assessed include environmental conditions, drying time, grape color, fungal contamination, and Ochratoxin A (OTA) levels. Grapes were dried in a controlled solar chamber and under open sun conditions. The solar chamber maintained higher average temperatures (34 °C) and lower relative humidity (39.7%) than outside conditions (24.2 °C and 58.7%, respectively), significantly reducing the drying time from 12 to 7 days. Raisins dried in the solar chamber exhibited improved color quality, with higher Lightness (L*), Hue Angle (h), and Chroma (C*) values, attributed to minimized enzymatic and nonenzymatic browning. Mycological analysis revealed a substantial reduction in Aspergillus section Nigri contamination in chamber-dried raisins, with mean colony-forming units per gram significantly lower than those of sun-dried raisins. Consequently, OTA levels were also significantly reduced in chamber-dried raisins, with Centennial Seedless showing a mean concentration of 1.01 µg/kg compared to 2.66 µg/kg in sun-dried samples, and Sultanina showing 0.70 µg/kg versus 2.05 µg/kg, respectively. These findings underscore the advantages of using solar indirect dryers to enhance drying efficiency, improve color quality, and reduce fungal and OTA contamination, highlighting the importance of adopting controlled drying technologies for safer, higher-quality raisins.

In recent years, significant efforts to produce healthier wines has led to the replacement or reduction of the addition of sulfites, using alternative substances or techniques. Resveratrol and related biophenols seem to be of great interest, since beyond their protective nature and contrary to sulfites they can positively affect consumer health. These bioactive phytochemicals are naturally produced in grapes as evolutionary acquired mechanisms against pathogens and UV irradiation. However, despite the efforts made so far attempting to develop economic and industrially adopted isolation techniques, available quantities of these biophenols for commercial use are still quite limited. Therefore, such molecules are still not able to meet the needs of industrial use due to their prohibitive marketable cost. In this review we summarize the efforts that have been made to biosynthesize these molecules through alternative, innovative ways. Increasing interest in modern biotechnological approaches has shed light on the exploitation of metabolically engineered microbial factories, instead of plants, to produce molecules of industrial interest. Such approaches, also reviewed here, are expected to lower the cost and appear promising to produce enough surplus to attract further oenological experimentation upon yielding functional wines. This development is expected to attract further industrial attention, continuing the race to partially or totally replace the external addition of sulfites. We also review important physicochemical properties of resveratrol in relation to enriching wines.

A wide range of fungal species is associated with post-harvest spoilage of grapes. However, Aspergillus carbonarius is the primary fungus responsible for the contamination of grapes with ochratoxin A, a mycotoxin causing several confirmed health effects to humans and animals. Aiming to find a method, safe for the consumers, to prevent post-harvest decay and ochratoxin A contamination of grapes, the potential use of essential oils as preservatives was investigated. Essential oils of Origanum dictamnus (dittany) , Origanum onites (oregano) , Origanum microphyllum (marjoram) , Thymbra capitata (thyme) , Satureja thymbra (savory) , Rosmarinus officinalis (rosemary) , Laurus nobilis (laurel) and Salvia officinalis (sage) were tested. The essential oil components were identified by GC/MS analysis. A first evaluation of the effectiveness of essential oils was performed in vitro , at a range of concentrations up to 300 μL L -1 . Based on the results of the in vitro tests, the four most effective essential oils ( O. dictamnus , O. onites , T. capitata and S. thymbra ) were tested on Sultana grapes, during post-harvest storage. The four essential oils tested, having the carvacrol and/or thymol as a common component, at a high concentration, significantly reduced, or even completely inhibited the growth of the fungus, in all treatments. As revealed from the results, the essential oils of O. dictamnus , O. onites and S. thymbra were the most effective, causing total inhibition on the growth of the fungus with a minimum concentration of 100 μL L -1 , followed by the essential oil of T. capitata , total effective with a minimum concentration of 200 μL L -1 . Essential oils of O. microphyllum , L. nobilis , S. officinalis and R. officinalis , although they had a significant effect on the growth of A. carbonarius , failed to inhibit its growth completely at any of the concentrations tested.

Wetlands are of great importance for providing the appropriate conditions for the diversity of species and inhabitants living in these ecosystems and for a wide range of public goods and services (fresh water, air filtering, recreational and tourism opportunities). However, despite their importance, wetlands are continuously degraded due to various human activities at an alarming rate worldwide. In the context of this study and considering the rational management of wetlands and the inevitable impact of climate change, a wetland, spatiotemporal monitoring system is proposed, implemented in the karst wetland of Almyros Stream (Heraklion, Crete, Greece). The implementation of this system is based on robust techniques from the allied fields of chemistry, earth and ecology assisted by GIS techniques. Our results indicate that this Mediterranean karst wetland of great ecological importance is under pressure because of pollution, climate change and land change. This argument is supported by (a) the high concentrations of water photosynthetic pigments and nutrients at certain times of the year, both provided by chemical analysis and partially verified by geophysical monitoring (spectral induced polarization) and (b) the high values of soil magnetic susceptibility at sites close to human infrastructures that is an indicator of heavy metals concentrations.

As the demand for high-quality wild greens rises, due to their high nutritional, culinary, and medicinal properties, the potential overexploitation and excessive disruption of their natural habitats bring serious environmental problems to the foreground. However, new alternative cultivation techniques, such as hydroponic cultivation, could take advantage of rational water management, optimal fertilization management and climate adaptation, to produce high-quality wild greens, all year round. As an initial step to assess optimal hydroponic cultivation conditions for golden thistle (Scolymus hispanicus L.), in this study we evaluated the effect of N:K ratio and electrical conductivity (EC) in the supplied nutrient solution on plant growth, yield and phenology. Four nutrient solutions were applied with a low or a high N:K ratio (1.59 or 2.38 mol/mol, respectively) combined with a low or a high electrical conductivity (EC) level (2.2 and 2.8 dS m−1, respectively) in a 2 × 2 factorial experiment set as a completely randomized block design with 4 blocks and 48 plants per block. Golden thistle seedlings were planted in plastic growth-bags of hydroponic perlite substrate in an open, drip-irrigated, soilless cultivation system. The experiment commenced in December 2018, in a plastic greenhouse at the campus of the Hellenic Mediterranean University, Crete, Greece. After four months of cultivation, the post-harvest analysis showed that the high N:K ratio significantly increased the fresh weight of leaf and edible tuberous root, whereas the tested EC levels in the nutrient solution had no impact on plant fresh weight. The experimental treatments did not significantly affect leaf chlorophyll concentration (SPAD meter readings), chlorophyll fluorescence (Fv/Fm) or the number of leaves and the specific weight of the tuberous root of the plants. Our results indicate that wild golden thistle could be domesticated as an edible vegetable, and cultivated hydroponically at different seasons of the year using relatively low nutrient concentrations, thereby minimizing aquifer nitrate and phosphate pollution. A nutrient solution with a relatively high N:K ratio (here 2.38 mol/mol) is recommended for the hydroponic cultivation of golden thistle.