Álvaro Peña-Neira

Chardonnay (Vitis vinifera L.) is one of the most widely cultivated white grape varieties in Chile, yet integrated studies addressing phenolic composition, polysaccharides, and color in commercial wines remain limited. This study characterized 30 commercial Chardonnay wines from major Chilean regions through a comprehensive analysis of phenolic composition, polysaccharide fractions, and CIELab color parameters, considering multiple sources of variability including vintage (2023–2024), closure type, geographic location, and valley of origin. Basic oenological parameters showed low variability, confirming their strong technological regulation in commercial wines. In contrast, total tannins, selected chromatic coordinates (particularly a* and hue angle), polysaccharide fractions, and several low-molecular-mass phenolics exhibited significant differences mainly associated with geographic origin and closure type. Among phenolic families, hydroxycinnamates, phenolic alcohols, and flavonols emerged as the most discriminant compositional domains. Multivariate analysis revealed that wine differentiation was structured by overlapping compositional gradients involving phenolic evolution, color expression, and polysaccharide composition rather than by vintage alone. Overall, the results highlight the multifactorial nature of Chardonnay wine composition and the combined contribution of grape origin, closure-associated bottle evolution, and winemaking factors. Nevertheless, because wines were commercially sourced and bottle age and storage conditions were not standardized, closure-associated differences should be interpreted cautiously as associations rather than causal effects.

Dry-farmed vineyards of Vitis vinifera L. cv. País in central–southern Chile represent one of the oldest viticultural systems in the Americas; however, objective compositional evidence supporting valley-scale typicity remains limited. This single-vintage study evaluated whether dry-farmed País wines from the Maule and Itata valleys exhibit compositional and sensory differences under standardized winemaking conditions. Ten monovarietal wines (2018 vintage; n = 5 per valley) were produced by controlled microvinification and analysed for general chemistry, phenolic composition, polysaccharides, chromatic attributes (CIELAB), and volatile compounds (SPME–GC–MS), together with descriptive sensory analysis by a trained panel. Total phenols (~1.2 g GAE L⁻¹), anthocyanins (~130 mg malvidin-3-glucoside equivalents L⁻¹), and tannins were low and comparable between valleys. However, differences were observed in specific compositional domains: Maule wines showed higher flavanols, polysaccharides, and aldehydes, whereas Itata wines exhibited higher ester levels. Sensory evaluation revealed differences in colour intensity, floral aroma, retronasal red-fruit notes, and astringency. Multivariate analysis (PCoA) revealed a structured but partial separation between valleys; however, this pattern was not supported by PERMANOVA, indicating limited statistical evidence for multivariate differentiation. These findings, based on a single vintage, suggest subtle compositional and sensory differences rather than strong valley-level typicity.

The diversification of craft beer styles has stimulated interest in innovative yeast-driven strategies to enhance sensory complexity while maintaining process robustness and stylistic integrity. In this context, non-Saccharomyces yeasts represent promising biotechnological tools for modulating fermentation performance and flavor development in brewing systems. This study evaluated the application of Lachancea thermotolerans and Torulaspora delbrueckii in the production of a Porter-style beer using sequential inoculation with Saccharomyces cerevisiae. All fermentations were conducted in triplicate from a wort with an original gravity of 1042. The final alcohol content ranged from 4.82 to 4.99% (v/v), and apparent attenuation varied between 84.1 and 88.9%, with no significant differences among treatments (p > 0.05). Color (92–94 European Brewery Convention (EBC) and bitterness (~18 International Bitterness Units (IBU) remained within Porter-style parameters across all fermentations. Total acidity ranged from 0.19 to 0.21% (lactic acid equivalents), while volatile acidity was significantly higher in the L. thermotolerans treatment (0.55 g L⁻¹) compared with the control (0.22 g L⁻¹) (p < 0.05). Sequential inoculation influenced early fermentation kinetics and modulated selected sensory attributes. Quantitative Descriptive Analysis (n = 18 panelists) indicated higher aroma intensity and foam quantity in beers produced with L. thermotolerans, whereas T. delbrueckii was associated with moderate increases in foam persistence. The roasted character and overall stylistic perception remained stable across treatments. These findings indicate that sequential inoculation with selected non-Saccharomyces yeasts enables measurable sensory differentiation in dark beer matrices without compromising fermentative performance or stylistic integrity. The results support their controlled integration as technological tools for sensory innovation in Porter-style beers.

In Chile, Pinot Noir is currently cultivated on 3937 hectares, representing 7.3% of the national vineyard area dedicated to wine production. Two distinct groups of Pinot Noir plant material coexist in commercial vineyards, as officially documented by the Chilean Ministry of Agriculture: historical mass selections introduced during the 19th century (e.g., Valdivieso: Val and Concha y Toro: C&T) and certified French clonal selections (notably 115 and 777) introduced in the 1990s. Given the relevance of phenolic compounds to wine quality—particularly their role in color stability and mouthfeel—wines produced from these selections were analyzed for spectrophotometric traits and individual phenolics using high-performance liquid chromatography. Results revealed variation in parameters associated with total phenolic content and wine composition. However, no consistent differentiation between clonal and massal-derived wines was observed. Overall, the findings suggest that, under commercial winemaking conditions, the genetic origin of the planting material exerts only a limited influence on the chemical composition of Chilean Pinot Noir wines.

The implementation of vegetative cover crops in vineyards is a sustainable alternative to chemical weed control, potentially influencing both soil fertility and grape-associated microbiota. This study evaluated the impact of six groundcover management strategies under vines—white clover (Trifolium repens), red clover (Trifolium pratense), burr medic (Medicago polymorpha), lupine (Lupinus albus), spontaneous weeds, and an herbicide-treated control—on the microbial dynamics and physicochemical properties of Cabernet Sauvignon must and wine from the Maipo Valley, Chile. Amplicon sequencing of bacterial (16S rRNA) and fungal (ITS) communities was combined with spontaneous fermentation trials and chemical analyses of must and wine. Fungal and bacterial communities on grape surfaces were dominated by Ascomycota and Proteobacteria, respectively, with no significant compositional differences among treatments. During fermentation, Metschnikowia and Tatumella were the most abundant non-Saccharomyces and bacterial genera, respectively, showing dynamic shifts across fermentation stages. Legume-based covers, particularly red clover, increased wine total acidity and polyphenol index while reducing pH. Correlation analyses revealed associations between specific microbial taxa (Metschnikowia, Cohnella, Saliterribacillus) and key enological parameters. Overall, these findings demonstrate that leguminous cover crops subtly modulate vineyard microbial ecology and fermentation outcomes, offering an environmentally sustainable pathway to enhance enological differentiation in semi-arid viticultural regions.

During red wine production, managing the pomace cap is key for a successful fermentation, allowing the extraction of phenolics and other metabolites and providing the necessary oxygen for yeast activity. In recent years, automatic cap management systems based on the injection of gases have gained popularity, despite the limited scientific information regarding the outcomes of their use. This trial aimed to evaluate the composition of wine during industrial red wine fermentations using an automatic sequential air injection system (i.e., AirMixing MI^TM). Fourteen lots of Cabernet Sauvignon grapes were fermented using four air injection regimes, where the intensity and daily frequency of air injections were set to either low or high. As expected, the treatment combining high-intensity and high-frequency air injection produced the largest dissolved oxygen peaks reaching up to 1.9 mg L⁻¹ per cycle, compared to 0.1 mg L⁻¹ in the low-intensity and low-frequency treatment. Yet, in all cases, little to no accumulation of oxygen overtime was observed. Regarding phenolics, the highest intensity and frequency of air injections led to the fastest increase in total phenolics, anthocyanins, short polymeric pigments, and tannin concentration, although compositional differences among treatments equilibrate by the end of fermentation. The main differences in phenolic compounds observed during fermentation were mediated by temperature variation among wine tanks. Based on these findings, it is advisable to keep the characterizing kinetics of phenolic extraction and expand the study to the aroma evolution of wines fermented with this technology.

Calcium tartrate instability in wines has been a neglected topic for many years. However, it seems that this problem is gaining prominence, and the industry welcomes inputs to address this issue. Among the alternatives that winemakers use for tartrate salt stabilization, the addition of authorized protective colloids is one of the best choices because they are easy to apply and have a low energetic cost. In the present study, the same red wine was treated with five different commercially available protective colloids in triplicate. The effectiveness of such colloids on calcium tartrate potential instability was estimated, in addition to their side effects on the phenolic composition of the treated wines and their astringency perception, as assessed by sensory analyses of the treated wine. The results show that, under these trial conditions, carboxymethylcellulose is the best choice for reducing the risk of calcium tartrate precipitation in wine. Moreover, the application of protective colloids to the wines had little effect on their color, phenolic composition, or evolution during one year of bottle storage. Finally, the addition of protective colloids did not impact the astringency intensity, but it influenced the dynamic perception of astringency according to the temporal dominance of sensation analysis.

The growth and development of green lettuce plants can be modulated by the prevailing light conditions around them. The aim of this study was to evaluate the effect of ambient light enrichment with different LED light spectra on agronomic characteristics, polyphenol concentration and relative gene expression of enzymes associated with polyphenol formation in ‘Levistro’ lettuce grown hydroponically in a Nutrient Film Technique (NFT) system for 28 days in a greenhouse. The spectra (blue:green:red:far-red) and red:blue (R:B) ratios obtained by enriching ambient light with Blue (B), White (W), Blue-Red (BR) and Red (R) LED light were B: 47:22:21:10, 0.5:1; W: 30:38:23:9, 0.8:1; BR: 33:15:44:8, 1.3:1 and R: 16:16:60:8, 3.8:1, respectively, and photosynthetically active radiation (PAR) under the different treatments, measured at midday, ranged from 328 to 336 µmoles m⁻² s⁻¹. The resulting daily light integral (DLI) was between 9.1 and 9.6 mol m⁻² day⁻¹. The photoperiod for all enrichment treatments was 12 h of light. The control was ambient greenhouse light (25:30:30:15; R:B = 1.2:1; PAR = 702 µmoles m⁻² s⁻¹; DLI = 16.9 mol m⁻² day⁻¹; photoperiod = 14.2 h of light). Fresh weight (FW) and dried weight percentage (DWP) were similar among the enrichment treatments and the control. The leaf number increased significantly under BR and R compared to B lights. The relative index of chlorophyll concentration (RIC) increased as plants grew and was similar among the enrichment treatments and the control. On the other hand, the concentration of chlorogenic acid and chicoric acid increased under BR and B lights, which was consistent with the higher relative expression of the coumarate 3-hydroxylase enzyme gene. In view of the results, it is inferred that half of the PAR or DLI is sufficient to achieve normal growth and development of ‘Levistro’ lettuce plants, suggesting a more efficient use of light energy under the light enrichment treatments. On the other hand, the blue and combined blue-red lights promoted the accumulation of phenolic compounds in the leaves of ‘Levistro’ lettuce plants.

The influence of the geographical location on the chemical composition of commercial Sauvignon Blanc wines was investigated. The assay was carried out on Sauvignon Blanc wines from three cold-climate valleys in Central Chile, Casablanca, Leyda, and San Antonio. The analyses revealed clear variations in some chemical parameters, especially in titratable acidity, which was higher in the geographical areas closest to the Pacific Ocean, such as the Leyda and San Antonio valleys. Regarding the composition of low-molecular-weight phenolic compounds, 17 compounds were found, and the results show that the Casablanca valley exhibits a greater abundance of monomeric flavanols, such as (+)-catechin, whereas the Leyda valley shows a higher abundance in flavonols and phenolic acids esterified with tartaric acid. Concerning the aromatic compound profile, the wines from the Casablanca valley showed a greater abundance of esters, C₁₃ norisoprenoids, and some terpenes. The PLS-DA analysis revealed some differences, especially between wines from Casablanca and Leyda, demonstrating that the difference in the chemical composition of the wines was influenced by the geographical area.

The genus Alstroemeria originates from South America, and Chile is one of the countries showing the highest number of taxa (49), of which 40 are endemic. However, anthropogenic and environmental factors are affecting the survival of these species; therefore, the conservation of their genetic variability is of great importance, and can be achieved through seed propagation. Seeds of this genus normally show dormancy, which prevents their germination under favorable conditions. The objective of this work was to understand the pre-germinative barriers to develop a seed propagation protocol for native alstroemerias and to determine the best method to break their dormancy. Seeds from 10 Alstroemeria species native to Chile were collected from the Coquimbo Region to Maule Region, and 5 pre-germination treatments combining scarification and stratification methods were evaluated. Moreover, a morphological and biochemical evaluation of the seeds was performed. The results showed a positive and significant effect on the percentage of emergence using seed soaking in water and cold stratification at 13 °C, obtaining the best results in A. pelegrina and A. angustifolia subsp. angustifolia (98.33% and 91.67%, respectively) after 30 days. The morphological characterization of seeds showed a wide range of size (diameter), from 2.18 mm (A. pulchra subsp. pulchra) up to 3.43 mm (A. pelegrina), and different shapes (pseudospherical and angular) and textures (rough and smooth). The highest phenol and tannin concentrations were observed in A. hookeri subsp. maculata with values of 4.71 and 30.95 mg g⁻¹ of seeds, respectively. A bigger size of the seed and a higher concentration of phenols could be related to a higher % of emergence of alstroemeria seeds.