Herbal distillates: A new era of grape marc distillates with enriched antioxidant profile

Chemometrically assisted differential pulse voltammetry for simultaneous and interference-free quantification of gallic and caffeic acids

This article explores the application of chemometric tools including multivariate curve resolution with alternating least squares for the simultaneous determination of gallic and caffeic acids on the surface of a glassy carbon electrode without additional modification. Gallic and caffeic acids are primary polyphenols, the most abundant in red wines produced in Argentina, and are often used as quality markers for them. These polyphenols significantly contribute to the organoleptic properties of wines from this origin, but their electrochemical signals overlap significantly, making simultaneous quantification challenging without additional experiments such as electrode modification or alternative analytical techniques beyond differential pulse voltammetry. This study successfully quantified these compounds in complex mixtures by generating second-order data from differential pulse voltammetry experiments conducted at various potential steps and subsequently applying multivariate curve resolution with alternating least squares. The use of constraints during optimization prevented rotational ambiguities common in this modeling, leading to unique results in validation samples. The limits of detection (LOD) found for gallic and caffeic acids were 1.6 and 7.6 mg L-1, which are in excellent agreement with the expected concentrations of these compounds in red wines. The concentration ranges analyzed showed a linear dependency (between the LOD and 300 mg L-1) with the signals estimated by the model for both analytes. Advantages such as simplicity, low cost, and high speed, as well as not requiring electrode modification, combined with excellent results obtained for real samples, make it a promising alternative for polyphenol analysis in the wine industry.

Effect of the storage process on quality characteristics of hemp-enriched "tsoureki" a rich-dough baked Greek product

The effects of the storage process on the quality characteristics of a hemp-enriched "tsoureki" (a rich-dough baked Greek product, rich-dough baked product [RDBP]) were investigated. The wheat flour was substituted with defatted hemp flour at selected ratios (0%-50% hemp:wheat flour). The baked products were stored at 25°C and at specific time intervals (0, 1, 4, 7, 10, and 14 days), and their properties were determined, including moisture content, water activity, structure, texture, color, total phenolic content (TPC), and antioxidant activity. Moreover, analyses of phenolic compounds were performed using quadrupole time of flight liquid chromatography-mass spectroscopy, identifying 14 compounds. Both the first-order kinetic model and modified Avrami equation, including the hemp-to-wheat ratio effect in the rate constant, well described the changes in the quality characteristics. The results showed that storage time and hemp incorporation significantly affected the quality of the product. Water activity decreased from 0.901 to 0.859, whereas moisture content decreased from 30.52%-32.33% (0 days) to 26.97%-27.02% w.b. (14 days) with storage time for all hemp additions. Hardness was greatly affected by hemp flour addition and approached 14.72 and 17.85 N after 14 days of storage for 30% and 50% substitutions, respectively. Springiness and cohesiveness decreased with hemp addition and storage time. The color difference of the hemp-enriched products compared to the control sample increased during storage. TPC increased due to the addition of hemp flour, whereas 14 compounds were identified. Based on property correlation, the hemp-enriched RDBP-tsoureki held its high-quality characteristics for 7 days of storage and contained a significant amount of bioactive compounds. PRACTICAL APPLICATION: Industrially produced, defatted hemp is a promising byproduct that can be used to nutritionally enhance baked goods. Modeling results can be used for the prediction of the properties that define product storage ability and also that the hemp-enriched, rich dough-baked Greek "tsoureki" could be produced while maintaining total phenolic content and antioxidant activity during 7 days of storage. These findings are expected to be used in the future in baked goods industry applications to produce goods with an improved nutritional profile.

The Metabolic and Antioxidant Activity Profiles of Aged Greek Grape Marc Spirits

In the last decade, "expressions" of grape marc spirits aged in wooden barrels of characteristic amber color and complex sensory attributes have been introduced. Yet studies on constituents migrating from the barrel to the beverage are scarce, and their metabolic profile remains unexplored. Furthermore, the literature on the assessment of their antioxidant activity is limited. NMR metabolomics and spectrophotometry have been implemented in 38 samples to elucidate the impact of the aging procedure on the metabolites' composition and establish whether these beverages exhibit antioxidant activity. Provenance was related to fusel alcohols, esters, acetaldehyde, methanol, saccharides, and 2-phenylethanol, while ethyl acetate and ethyl lactate contributed to discriminating samples of the same winery. Identified metabolites such as vanillin, syringaldehyde, and sinapaldehyde were related to the aging procedure. The maturation in the barrel was also associated with an increase in xylose, glucose, fructose, and arabinose. The antioxidant potential of the aged Greek grape marc spirits resulting from their maturation in oak barrels was highlighted. The metabolic profiling and antioxidant potential of aged Greek grape marc spirits were assessed for the first time. Finally, the enrichment of the aromatic region was noted with the presence of metabolites with a furanic and phenolic ring derived, respectively, from the polysaccharides' degradation or the thermal decomposition of lignin.

Optimization of an edible film formulation by incorporating carrageenan and red wine lees into fish gelatin film matrix

The study aimed to use response surface methodology (RSM) to create and understand a novel edible film made from fish gelatin (FG). This film includes wine lees (WL) and carrageenan (CAR). The concentrations of WL (0, 1, 2, and 3 %) and CAR (0, 1, and 3 %) were considered independent variables. The process variable combinations for the optimal response functions were 1.926 % WL and 3 % CAR, forming soft and rigid films with low tensile strength (TS) and high elongation at break (EAB%). Based on the evaluation of each response, FG film had the highest TS value, FG/CAR(3 %) film had the maximum EAB, and FG/WL (3 %)/CAR (3 %) film had the lowest vapor permeability (WVP) and the highest opacity (OP). The incorporation of WL considerably improved the functional properties of these films, enabling strong antioxidant activity and high phenolic content. Characterization of the films with analytical techniques: Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis demonstrated a considerable interaction between WL and FG, indicating a high level of compatibility between the two substances. Our data suggest that the formulation of edible films can be adjusted to fit the specific requirements of the design.

On the Assessment of Strawberries' Shelf-Life and Quality, Based on Image Analysis, Physicochemical Methods, and Chemometrics

The aim of the present study was to evaluate Marisol strawberries' (Fragaria × ananassa) physicochemical quality and shelf-life during storage, using an integrated analytical approach. More specifically, the research aimed to assess the strawberries' color, texture, and nutritional quality, over an 11-day storage period, employing physicochemical analyses, spectrophotometric assays, Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy, image analysis, and statistical tools. The results revealed significant changes in the outer surface texture and color characteristics, indicating spoilage progression. Physicochemical parameters such as water activity, moisture content, soluble solids, titratable acidity, and ascorbic acid content exhibited significant alterations, influencing the taste profile and freshness perception. Antioxidant and antiradical activities showed fluctuations, suggesting a potential decrease in phenolic content during storage. Moreover, the ATR-FTIR spectra findings confirmed the results regarding the moisture content, soluble solids, and total phenolic content. The integration of physicochemical and image analysis-derived features through a principal component analysis (PCA) enabled the accurate classification of samples based on storage days. Regression analysis, using these features, successfully predicted the storage day with high accuracy. Overall, this integrated analytical approach provided valuable information on the estimation of Marisol strawberries' shelf-life and the prediction of their quality deterioration, contributing to better fruit management and the minimization of discards.

Optimization of Ultrasound-Assisted Extraction and Characterization of the Phenolic Compounds in Rose Distillation Side Streams Using Spectrophotometric Assays and High-Throughput Analytical Techniques

Lately, the essential oils industry has been one of the most expanding markets globally. However, the byproducts generated after the distillation of aromatic plants and their transformation to novel high-added value products consist of a major up-to-date challenge. Thus, the scope of the current study is the optimization of ultrasound-assisted extraction (UAE) for the recovery of phenolic compounds from rose (Rosa damascena) post-distillation side streams using Box-Behnken design. In particular, the highest total phenolic content (TPC) was achieved at 71% v/v ethanol-water solution, at 25 min, 40 mL/g dry sample and 53% ultrasound power, while ethanol content and extraction time were the most crucial factors (p-value ≤ 0.05) for UAE. Both solid (RSB) and liquid (LSB) rose side streams exhibited significant antiradical and antioxidant activities. The interpretation of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra confirmed the presence of compounds with properties such as phenolic compounds, phenolic amide derivatives, and alcohols in the extracts. Moreover, the flavonoids naringenin, quercetin, and kaempferol were the major phenolic compounds, identified in the extracts by liquid chromatography-tandem mass spectrometry analysis (LC-MS/MS), followed by gallic, protocatechuic, p-hydroxybenzoic, and rosmarinic acids. Furthermore, the LC-MS/MS results pinpointed the effect of factors other than the extraction conditions (harvesting parameters, climatic conditions, plant growth stage, etc.) on the phenolic fingerprint of RSB extracts. Therefore, RSB extracts emerge as a promising alternative antioxidant agent in food products.

Polyphenol Composition by HPLC-DAD-(ESI-)MS/MS and Bioactivities of Extracts from Grape Agri-Food Wastes

BACKGROUND

Grape agri-food wastes, such as skin, seeds, and other discarded by-products, contain phytochemical compounds that offer potential health benefits.

METHODS

This study aimed to investigate the polyphenol composition and bioactivities of different extracts obtained from grape marc and seeds, with the goal of exploring their potential for application as natural food additives.

RESULTS

Regardless of the extraction method used (dynamic maceration, ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE)), all extracts exhibited relatively high concentrations of phenolic compounds. The chemical characterization of the extracts revealed the presence of specific compounds and chemical groups associated with each extraction methodology. Moreover, the extracts displayed satisfactory antioxidant activities, especially in inhibiting lipoperoxidation as assessed by the TBARS assay. Additionally, the extracts demonstrated effective inhibition against different strains of bacteria and fungi known as food contaminants. Taken together, these findings indicate that those extracts have the potential to be tested as natural antioxidants and preservatives with sustainable origins in food and beverage systems. Among the extraction methods evaluated, traditional maceration and UAE provided extracts with the highest antioxidant and antimicrobial activities.

CONCLUSIONS

Our results suggest the opportunity to explore grape marc and seeds discarded by the winery industry in Portugal as natural sources of bioactive compounds, which could be employed as functional food ingredients or technological additives. The valorization of grape biowastes offers a promising strategy to reduce waste and harness their potential health benefits.

Efficiency of Lactiplantibacillus plantarum JT-PN39 and Paenibacillus motobuensis JT-A29 for Fermented Coffee Applications and Fermented Coffee Characteristics

To develop a process for low-cost and ecologically friendly coffee fermentation, civet gut bacteria were isolated and screened to be used for fermentation. Among 223 isolates from civet feces, two bacteria exhibited strong protease, amylase, lipase, pectinase, and cellulase activities. By analyzing 16S rDNA phylogeny, those bacteria were identified to be Lactiplantibacillus plantarum JT-PN39 (LP) and Paenibacillus motobuensis JT-A29 (PM), where their potency (pure or mixed bacterial culture) for fermenting 5 L of arabica parchment coffee in 48-72 h was further determined. To characterize the role of bacteria in coffee fermentation, growth and pH were also determined. For mixed starter culture conditions, the growth of PM was not detected after 36 h of fermentation due to the low acid conditions generated by LP. Coffee quality was evaluated using a cupping test, and LP-fermented coffee expressed a higher cupping score, with a main fruity and sour flavor, and a dominant caramel-honey-like aroma. Antioxidant and anti-foodborne pathogenic bacteria activity, including total phenolic compounds of PM and LP fermented coffee extracts, was significantly higher than those of ordinary coffee. In addition, LP-fermented coffee expressed the highest antibacterial and antioxidant activities among the fermented coffee. The toxicity test was examined in the murine macrophage RAW 264.7 cell, and all fermented coffee revealed 80-90% cell variability, which means that the fermentation process does not generate any toxicity. In addition, qualifications of non-volatile and volatile compounds in fermented coffee were examined by LC-MS and GC-MS to discriminate the bacterial role during the process by PCA plot. The flavors of fermented coffee, including volatile and non-volatile compounds, were totally different between the non-fermented and fermented conditions. Moreover, the PCA plot showed slightly different flavors among fermentations with different starter cultures. For both the cupping test and biological activities, this study suggests that LP has potential for health benefits in coffee fermentation.

Quality Assessment of Ground Coffee Samples from Greek Market Using Various Instrumental Analytical Methods, In Silico Studies and Chemometrics

Coffee is one of the most widely consumed beverages worldwide due to its sensory and potential health-related properties. In the present comparative study, a preparation known as Greek or Turkish coffee, made with different types/varieties of coffee, has been investigated for its physicochemical attributes (i.e., color), antioxidant/antiradical properties, phytochemical profile, and potential biological activities by combining high-throughput analytical techniques, such as infrared spectroscopy (ATR-FTIR), liquid chromatography-tandem mass spectrometry (LC-MS/MS), and in silico methodologies. The results of the current study revealed that roasting degree emerged as the most critical factor affecting these parameters. In particular, the L* color parameter and total phenolic content were higher in light-roasted coffees, while decaffeinated coffees contained more phenolics. The ATR-FTIR pinpointed caffeine, chlorogenic acid, diterpenes, and quinic esters as characteristic compounds in the studied coffees, while the LC-MS/MS analysis elucidated various tentative phytochemicals (i.e., phenolic acids, diterpenes, hydroxycinnamate, and fatty acids derivatives). Among them, chlorogenic and coumaric acids showed promising activity against human acetylcholinesterase and alpha-glucosidase enzymes based on molecular docking studies. Therefore, the outcomes of the current study provide a comprehensive overview of this kind of coffee preparation in terms of color parameters, antioxidant, antiradical and phytochemical profiling, as well as its putative bioactivity.

Potential Health Benefits of Banana Phenolic Content during Ripening by Implementing Analytical and In Silico Techniques

Banana ranks as the fifth most cultivated agricultural crop globally, highlighting its crucial socio-economic role. The banana's health-promoting benefits are correlated with its composition in bioactive compounds, such as phenolic compounds. Thus, the present study attempts to evaluate the potential health benefits of banana phenolic content by combing analytical and in silico techniques. Particularly, the total phenolic content and antioxidant/antiradical activity of banana samples during ripening were determined spectrophotometrically. In parallel, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was implemented to unravel the variations in the phenolic profile of banana samples during ripening. Chlorogenic acid emerged as a ripening marker of banana, while apigenin and naringenin were abundant in the unripe fruit. In a further step, the binding potential of the elucidated phytochemicals was examined by utilizing molecular target prediction tools. Human carbonic anhydrase II (hCA-II) and XII (hCA-XII) enzymes were identified as the most promising targets and the inhibitory affinity of phenolic compounds was predicted through molecular docking studies. This class of enzymes is linked to a variety of pathological conditions, such as edema, obesity, hypertension, cancer, etc. The results assessment indicated that all assigned phenolic compounds constitute great candidates with potential inhibitory activity against CA enzymes.

Predictive Evaluation of Microbiological Stability of Soft Drinks with Lycium barbarum L. Stored at Temperature Shifts

Lycium barbarum L., used in Chinese traditional medicine for centuries, has gained popularity in Europe in the last decade because of its health-promoting properties assigned to phenolic compounds and antioxidant activity. Goji fruits and extracts are often used as ingredients in popular homemade milk cocktails. Within this study, the microbiological stability of the milkshake, with the addition of berries from NingXia Province and their extract, was evaluated using the ComBase^® prognostic model. The extraction of dry berries in water at 70 °C for 72 h produced an extract showing radical inhibition of 64.9% and a total phenol content of 63.6 mg g⁻¹. The phenolic compounds with the highest concentrations were in turn: 3-hydroxybenzoic acid, gallic acid, procyanidin B2, and catechin. The milkshake inoculated with the reference B. subtilis was a model for the study of its microbiological stability. Using ComBase^®, a microbiological response to the delayed cooling of goji berry extract and the milkshake with the addition of goji berries was predicted and the model’s accuracy assessed. The best-performing models were constructed for extract (Bias factor B_f 1.33, Accuracy factor A_f 3.43) and milkshake (B_f 1.29, A_f 1.65) in a profile simulating delayed refrigeration (22.5 °C–9 °C–23 °C). Despite discrepancies between predicted and observed bacterial growth due to the antimicrobial effect of the derivatives of goji berries, the models were validated as „overpredict”, i.e., „fail safe”, and may be used to prognose the stability of these products in the given temperature profile.

In Vitro and In Silico Studies to Assess Edible Flowers’ Antioxidant Activities

The incorporation of edible flowers in the human diet and culinary preparations dates back to ancient times. Nowadays, edible flowers have gained great attention due to their health-promoting and nutritive effects and their widespread acceptance by consumers. Therefore, edible flowers are ideal candidates for use in the design and development of functional foods and dietary supplements, representing a new and promising trend in the food industry. Thus, the present study attempts to assess the potential of various edible flowers against oxidative stress by applying a combination of in vitro, in silico and spectroscopic techniques. Specifically, the spectroscopic profiles of edible flower extracts were evaluated using ATR-FTIR spectroscopy, while their total phenolic contents and antioxidant/antiradical activities were determined spectrophotometrically. The most abundant phytochemicals in the studied flowers were examined as enzyme inhibitors through molecular docking studies over targets that mediate antioxidant mechanisms in vivo. Based on the results, the red China rose followed by the orange Mexican marigold exhibited the highest TPCs and antioxidant activities. All samples showed the characteristic FTIR band of the skeletal vibration of phenolic aromatic rings. Phenolic compounds seem to exhibit antioxidant activity with respect to NADPH oxidase, myeloperoxidase (MP), cytochrome P450 and, to a lesser extent, xanthine oxidase (XO) enzymes.

Towards the Optimization of Microwave-Assisted Extraction and the Assessment of Chemical Profile, Antioxidant and Antimicrobial Activity of Wine Lees Extracts

Wine lees, a sub-exploited byproduct of vinification, is considered a rich source of bioactive compounds, such as (poly)phenols, anthocyanins and tannins. Thus, the effective and rapid recovery of these biomolecules and the assessment of the bioactive properties of wine lees extracts is of utmost importance. Towards this direction, microwave-assisted extraction (MAE) factors (i.e., extraction time, microwave power and solvent/material ratio) were optimized using experimental design models in order to maximize the (poly)phenolic yield of the extracts. After optimizing the MAE process, the total phenolic content (TPC) as well as the antiradical, antioxidant and antimicrobial activity of the extracts were evaluated. Furthermore, Fourier transform infrared spectroscopy (FTIR) was employed to investigate the chemical profile of wine lees extracts. Red varieties exhibited higher biological activity than white varieties. The geographical origin and fermentation stage were also considered as critical factors. The white variety Moschofilero presented the highest antioxidant, antiradical and antimicrobial activity, while Merlot and Agiorgitiko samples showed noteworthy activities among red varieties. Moreover, IR spectra confirmed the presence of sugars, amino acids, organic acids and aromatic compounds. Thus, an efficient, rapid and eco-friendly process was proposed for further valorization of wine lees extracts.

Impact of tannin addition on the antioxidant activity and sensory character of Malagousia white wine

Enological tannins are assessed as promising alternative to SO2 in order to control oxidative process during winemaking, due to allergic reactions incurred by sulfite sensitive individuals. In the present study, the commercial enological Tara tannin "Vitanil B″ was added, as alternative to the addition of sulfites, at different concentrations (100-500 mg/L) in white wine from grapes of Vitis vinifera L. var. Malagousia in order to enhance antioxidant stability and sensory character of the wine. Considering photometric analyses and chromatic parameters results, tannin addition (300 mg/L) in Malagousia enhanced total phenolic content, antioxidant and antiradical activity and prevented color deterioration, for a storage period of 100 d, compared to control and sulfited wines. Moreover, aroma quality, body, after taste and overall acceptance of wine treated with 300 mg/L tannin, were highly appreciated and received the highest scores. The overall evaluation of tannin addition was performed by Principal Component Analysis, leading to discrimination of wines, according to photometric, color and sensory analysis parameters. Conclusively, tannin addition resulted in a considerable increase of total phenolic content, antioxidant and antiradical activity, compared to the control and sulfited wines, maintaining the sensory parameters and overall acceptance of Malagousia wine.

Combined Effect of Impregnation with an Origanum vulgare Infusion and Osmotic Treatment on the Shelf Life and Quality of Chilled Chicken Fillets

The scope of this work is the study of a combined process including a dipping step into an oregano (Origanum vulgare ssp. hirtum) infusion (OV) followed by osmotic treatment of chicken fillets at 15 °C. Chicken fillets were immersed in an osmotic solution consisting of 40% glycerol and 5% NaCl with (OV/OD) and without (OD) prior antioxidant enrichment in a hypotonic oregano solution. A comparative shelf life study of all the samples (untreated, OD and OV/OD treated) was then conducted at 4 °C in order to assess the impact of this process on the quality and shelf life of chilled chicken fillets. Microbial growth, lipid oxidation and color/texture changes were measured throughout the chilled storage period. Rates of microbial growth of pretreated fillets were significantly reduced, mainly as a result of water activity decrease (OD step). Rancidity development closely related to off odors and sensory rejection was greatly inhibited in treated fillets owing to both inhibitory factors (OD and OV), with water-soluble phenols (OV step) exhibiting the main antioxidant effect. Shelf life of treated chicken fillets exhibited a more than three-fold increase as compared to the untreated samples based on both chemical and microbial spoilage indices, maintaining a positive and pleasant sensory profile throughout the storage period examined.

Expanding the Role of Sub-Exploited DOE-High Energy Extraction and Metabolomic Profiling towards Agro-Byproduct Valorization: The Case of Carotenoid-Rich Apricot Pulp

Traditional extraction remains the method-of-choice for phytochemical analyses. However, the absence of an integrated analytical platform, focusing on customized, validated extraction steps, generates tendentious and non-reproducible data regarding the phytochemical profile. Such a platform would also support the exploration and exploitation of plant byproducts, which are a valuable source of bioactive metabolites. This study deals with the incorporation of (a) the currently sub-exploited high energy extraction methods (ultrasound (UAE)- and microwave-assisted extraction (MAE)), (b) experimental design (DOE), and (c) metabolomics, in an integrated analytical platform for the extensive study of plant metabolomics and phytochemical profiling. The recovery of carotenoids from apricot by-products (pulp) is examined as a case study. MAE, using ethanol as solvent, achieved higher carotenoid yields compared to UAE, where 1:1 chloroform-methanol was employed, and classic extraction. Nuclear magnetic resonance (NMR)-based metabolomic profiling classified extracts according to the variations in co-extractives in relation to the extraction conditions. Extracts with a lower carotenoid content contained branched-chain amino acids as co-extractives. Medium carotenoid content extracts contained choline, unsaturated fatty acids, and sugar alcohols, while the highest carotenoid extracts were also rich in sugars. Overall, the proposed pipeline can provide different the phytochemical fractions of bioactive compounds according to the needs of different industrial sectors (cosmetics, nutraceuticals, etc.).

Physicochemical and aromatic characterization of carob macerates produced by different maceration conditions

Carob liqueur is an alcoholic drink (minimum 15% v/v of ethanol and 100 g/L of sugar) typical for the Mediterranean countries. In the current work, carob macerate produced by maceration of carob pods in hydroalcoholic base at different maceration conditions was characterized for the first time based on its aroma compounds/profile, physicochemical parameters, and chromatic characteristics. The results confirm the migration process of bioactive compounds, aroma compounds, and sugars flowing from the carob pod to the hydroalcoholic base. Changes in ethanol concentration modify the physical properties of the solvent and influence the phenolic and aroma compounds extraction, color, and acidity of the obtained samples. The higher content of phenolic compounds was determinate in the samples obtained in the darkness. The amounts of phenols were in the range of some red fruit liqueurs or walnut liqueurs, and sugars (mostly sucrose) ranging between 96 and 107 g/L. Twenty-six (out of total 94) aroma compounds were detected in all samples, of which 17 esters, 3 alcohols, 4 ketones, and 2 acids. Low molecular weight ethyl esters, ethyl hexanoate, ethyl 2-methyl propanoate, ethyl octanoate, ethyl benzoate, ethyl butanoate, and ethyl cinnamate, were the most abundant. Carob pod maceration in 50% v/v hydroalcoholic base (1:5 solid to liquid ratio) in darkness at room temperature during 8 weeks can be recommended as optimal maceration conditions for production of the aromatic carob macerate with functional properties.

Effects of Infrared Radiation on Eggplant (Solanum melongena L.) Greenhouse Cultivation and Fruits' Phenolic Profile

The implementation of Infrared (IR) radiation in heated greenhouses possesses the advantage of high directional control and focused compensation of energy losses, appropriate for creating local microclimate conditions in highly energy-consuming systems, such as greenhouses. Moreover, it can efficiently maintain favorable environmental conditions at the plant canopy. The present study studies the application of Infrared (IR) heating in an experimental greenhouse with eggplant (Solanum melongena L.) cultivation. The experimental results are presented from a full cultivation period inside two identical, small scale experimental greenhouses, with IR and forced air heating system, respectively. The effects of IR heating over plant growth parameters, including the yield of the fruits as well as the total phenolic content and the antioxidant profile of eggplants fruits’ extracts are measured and discussed. The results indicate a greater uniformity production in the IR heating greenhouse in terms of antioxidant and radical scavenging activities, as well as the total phenolic content. Moreover, the phenolic profile of eggplant fruits from both greenhouses revealed the existence of numerous bioactive compounds, some of which were only characteristic of the eggplant fruits from IR heated greenhouses.

Shelf Life Extension and Improvement of the Nutritional Value of Fish Fillets through Osmotic Treatment Based on the Sustainable Use of Rosa damascena Distillation By-Products

The objective of this work is the comparative study of different osmotic treatments at 37 °C on the quality and shelf life of chilled sea bass fillets. Fish fillets were treated using osmotic solutions consisting of oligofructose (40%–50%–60%) and 5% NaCl with (BP/OT) and without (OT) former antioxidant enrichment by using Rosa damascena distillation by-products. Water activity decreased to approximately 0.95 after 330 minutes of osmotic treatment. Untreated and osmotically treated fish fillets (BP/OT) and (OT) were subsequently stored at 5 °C and their quality was evaluated based on microbial growth and lipid oxidation. Osmotic treatment extended significantly the shelf life of fish in terms of microbial growth; however, it also accelerated its lipid oxidation. The impregnation of Rosa damascena phenolics not only counterbalanced this negative effect, but led to a more than four-fold increase of the shelf life of sea bass, as compared to the untreated samples.

Evaluating the experimental cultivation of peppers in low-energy-demand greenhouses. An interdisciplinary study

BACKGROUND

Photovoltaics (PV) provide an alternative solution to cover energy demands in greenhouses. This study evaluates the effect of PV panels installed on the roofs of greenhouses, and the partial shading that they cause, on the growth parameters and growth indicators of the experimental cultivation of peppers (Capsicum annuum cv. California Wonder). The growth of the plants, the antioxidant profile, radical scavenging activity, total phenolic content, and the phenolic and metabolic profiles (using LC-MS spectrometry and NMR spectroscopy) are evaluated.

RESULTS

Data are presented from a full cultivation period. Results indicated that indoor temperatures were similar for both glass and glass-PV (glass with PV panels installed) greenhouses during the day and the night. The production yield was higher for the glass-PV greenhouses. The pepper fruits' weight, dimensions, and thickness were similar in both cases. Comparison of the pepper fruit extracts in terms of total phenolic content, antioxidant, and antiradical activities indicated differences that were not statistically significant. Photometric and spectroscopic studies both showed a smaller distribution of values in the case of the glass-PV greenhouse, probably indicating a more consistent phytochemical profile.

CONCLUSION

Covering only a small proportion (ca. 20%) of the greenhouse roof with photovoltaic panels contributes considerably to its energy demands without affecting plant growth and quality. © 2018 Society of Chemical Industry.

On the Characterization and Correlation of Compositional, Antioxidant and Colour Profile of Common and Balsamic Vinegars

Commercially available common and balsamic vinegars were examined, using a combination of spectrophotometric, chromatographic, colorimetric and spectroscopic methods. Total phenolic content, antioxidant activity, radical scavenging capacity, phenolic profile, colour parameters, Fourier Transform Infrared (FT-IR) absorbance spectra and Nuclear Magnetic Resonance (¹H NMR) spectra were comparatively studied. The main scope was the assessment of vinegar antioxidant and metabolic profiles and the identification of the most appropriate features influencing their type and subtypes. Red grape balsamic vinegars exhibited the strongest antioxidant profile. High total phenolic content and radical scavenging-antioxidant activity of vinegars was strongly correlated with high hue-angle and colour density values and low lightness and a* values. FT-IR spectra analysis confirmed the presence of organic acids and carbohydrates and, in combination with Gas Chromatography-Mass Spectrometry (GC-MS), the occurrence of phenolic compounds. NMR spectroscopy enabled the identification of 27 characteristic metabolites in each type of vinegar. The combination of all applied techniques provides critical information on compositional differences among the vinegars and could serve as an application tool for similar fermentation products.

Optimization of Polyphenol Extraction from Allium ampeloprasum var. porrum through Response Surface Methodology

Allium ampeloprasum var. porrum has been recognized as a rich source of secondary metabolites, including phenolic acids, flavonoids and flavonoid polymers (proanthocyanidins or condensed tannins), with related health benefits. Both parts of Allium ampeloprasum var. porrum (white bulb and pseudostem) are traditionally consumed either as a vegetable or as a condiment in many Mediterranean countries. The aim of the present study was to optimize the extraction conditions of polyphenols from white leek stem and green leek leaf by implementing a Box-Behnken design (BBD). The optimization considered basic factors affecting extraction efficiency, including extraction time, solvent to plant material ratio and solvent mixture composition. Maximum polyphenol yield was achieved at an extraction time of 80 and 100 min for white leek stem and green leek leaf extracts respectively, solvent to plant material ratio of 5:1 (v/w) and methanol to water ratio of 40:60 (v/v), for both leek extracts. Interestingly, higher total phenolic content was found in green leek leaf extracts compared to white leek stem extracts, due to a possible relationship between polyphenol production and sunlight radiation. High correlation values were also observed between total phenolic content and antioxidant-antiradical activity of optimized leek extracts.