Study of phenolic profile and antioxidant activity in selected Moravian wines during winemaking process by FT-IR spectroscopy

White wine phenolics: current methods of analysis

White wine phenolic analyses are less common in the literature than analyses of red wine phenolics. Analytical techniques for white wine phenolic analyses using spectrophotometric, chromatographic, spectroscopic, and electrochemical methods are reported. The interest of research in this area combined with the advances in technology aimed at the winemaking industry are promoting the establishment of novel approaches for identifying, quantifying, and classifying phenolic compounds in white wine. This review article provides an overview of the current research into white wine phenolics through a critical discussion of the analytical methods employed. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Polyphenols from Dichrostachys cinerea Fruits Anti-Inflammatory, Analgesic, and Antioxidant Capacity in Freund’s Adjuvant-Induced Arthritic Rat Model

Dichrostachys cinerea (L.) Wigth & Arn. (DC) is widely used in traditional medicine against several inflammatory diseases, especially rheumatoid arthritis, because of its antioxidant and anti-inflammatory effects. This study aimed to characterize the polyphenol-rich DC fruit extracts and investigate the analgesic, anti-inflammatory, and antioxidant effects in a rat inflammation model induced by complete Freund’s adjuvant (CFA). Water and ethanolic extracts were characterized using liquid chromatography coupled with mass spectrometry (LC-MS), Fourier-transform infrared (FTIR) spectroscopy, and gas chromatography coupled with mass spectrometry (GC-MS). The polyphenol-rich extracts were administered in three different concentrations for 30 days. Pain threshold, thermal hyperalgesia, edema, and serum biomarkers specific to inflammatory processes or oxidative stress were evaluated. Both extracts were rich in polyphenolic compounds, mainly flavan-3-ols, proanthocyanidins, and flavone glycosides, which had important in vitro antioxidant capacity. DC fruit extracts administration had the maximum antinociceptive and anti-inflammatory effects after one day since the CFA injection and showed promising results for long-term use as well. The measurement of pro-inflammatory cytokines, cortisol, and oxidative stress parameters showed that DC extracts significantly reduced these parameters, being dose and extract-type dependent. These results showed potential anti-inflammatory, analgesic, and antioxidative properties and revealed the necessity of using a standardized polyphenolic DC extract to avoid result variability.

Fourier transform infrared spectroscopy in monitoring the wine production

The complexity of the wine matrix makes monitoring of the winemaking process from the grapes to the final product crucial for the wine industry. In this context, analytical methodologies that can combine good accuracy, robustness, high sample throughput, “green character”, and by preference real-time analysis, are on-demand to create high-quality vitivinicultural products. In the last years, Fourier-transform Infrared Spectroscopy (FTIR) combined with chemometric analysis has been evaluated in several studies as an effective analytical tool for the wine sector. Some applications of FTIR spectroscopy have been already accepted by the wine industry, mainly for the prediction of basic oenological parameters, using portable and non-portable instruments, but still many others are waiting to be thoroughly developed. This literature review aims to provide a critical synopsis of the most important studies assessing grape and wine quality and authenticity, and to identify possible gaps for further research, meeting the needs of the modern wine industry and the expectations of most demanding consumers. The FTIR studies were grouped according to the main sampling material used - 1) leaves, stems, and berries; 2) grape must and wine applications - along with a summary of the basic limitations and future perspectives of this analytical technique.

Fermentation Condition and Quality Evaluation of Pineapple Fruit Wine

This research investigated the impact of the concentration of pineapple juice on the characteristics of pineapple wine during fermentation with Saccharomyces cerevisiae var. burgundy. Three ratios of fresh pineapple juice to water were mixed to obtain three treatments, which were T1—2:1, T2—1:1, and T3—1:2. The °Brix and pH of all pineapple juice and water ratios were adjusted to 25 and 4, respectively. The results showed that changes in alcohol, pH, Total Soluble Solids (TSS), Total Titratable Acidity (TAA, as citric acid), and Volatile Acidity (VA, as acetic acid) during the 10-day fermentation among three treatments were significantly different. The highest alcohol content was obtained from the 2:1 with values of 10.71% (v/v). The mixed ratio at 1:1 and 1:2 obtained the alcohol value of 9.61 and 8.35% (v/v), respectively. After ten days of fermentation, TSS, pH values, TAA, and VA were in the range of 9.7–13 °Brix, 3.56–3.82, 0.384–0.448, and 0.0013–0.0016, respectively. However, the appearance, aroma, and taste of all ratios were not significantly different. Sweetness and overall liking, wine with pineapple juice/water ratio at 2:1 had the highest score (p ≤ 0.05). The total antioxidant activities determined by DPPH and total phenolic content were 0.91 mmol/L TE and 365.80 mg/L GAE, respectively, as confirmed by FTIR spectral analyses.

Modeling the drying of ultrasound and glucose pretreated sweet potatoes: The impact on phytochemical and functional groups

The influence of ultrasonic frequency (20 kHz) and glucose pretreatments either alone or in combination on the drying of sweet potato slices (3 mm) using a hot-air dryer at 60 °C was tested to study the kinetics modeling, phytochemicals, antioxidant activities, and functional and textural changes of the final dried product. The results indicated that total phenolic content and total flavonoid content were significantly higher in glucose-pretreated samples while antioxidant activities were higher in ultrasound- and glucose-pretreated samples. For vitamin C, much degradation occurred in the glucose-pretreated samples when compared with the other pretreated samples apart from the control. Enzymatic browning made a minor contribution to the ultrasound/glucose-pretreated samples, while no significant differences were noted in the glucose-pretreated samples. A modified Henderson and Pabis (MHP) model, followed by the two-term and Hii models, fitted best among the 15 selected mathematical models. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed the presence of glucose, phenols, and flavonols in all samples. Microstructural analysis confirmed the hardness (N) in the final glucose-pretreated samples due to glucose layers and less cell damage.

Evolution of phenolic profile of white wines treated with enzymes

The aim of this study is to monitor the evolution of the principal phenolic compounds throughout the fermentation stage of white wines treated with different enzymes. The effect of five commercial enzymes on the evolution of the phenolic profile during the alcoholic fermentation of white wines obtained from Fetească regală and Sauvignon blanc varieties was evaluated. Physicochemical properties of resulted wine samples have been analyzed according to OIV standards and regulations. The evolution of the principal phenolic compounds was carried out using HPLC method. Enzymatic treatments did not significantly affect the physicochemical composition of the obtained wines. The analyzed samples showed different variations on the phenolic compound content, depending on the type of added enzyme and grape variety. The statistical analysis confirms that enzymes significantly contributed to the enrichment of the wines with phenolic compounds, especially with p-coumaric, gentisic, caftaric, and protocatechuic acids.

Thermal Isolation of a Clean Alloy from Waste Slag and Polymeric Residue of Electronic Waste

Unprecedented advances and innovation in technology and short lifespans of electronic devices have resulted in the generation of a considerable amount of electronic waste (e-waste). Polymeric components present in electronic waste contain a wide range of organic materials encompassing a significant portion of carbon (C). This source of carbon can be employed as a reducing agent in the reduction of oxides from another waste stream, i.e., steelmaking slag, which contains ≈20 wt%–40 wt% iron oxide. This waste slag is produced on a very large scale by the steel industry due to the nature of the process. In this research, the polymeric residue leftover from waste printed circuit boards (PCBs) after a physical-chemical recycling process was used as the source of carbon in the reduction of iron oxide from electric arc furnace (EAF) slag. Prior to the recycling tests, the polymer content of e-waste was characterized in terms of composition, morphology, thermal behavior, molecular structure, hazardous elements such as Br, the volatile portion, and the fixed carbon content. After the optimization of the ratio between the waste slag (Fe source) and the waste polymer (the carbon source), the microstructure of the recycled alloy showed no Br, Cl, S, or other contamination. Hence, two problematic and complex waste streams were successfully converted to a clean alloy with 4 wt% C, 4% Cr, 2% Si, 1% Mn, and 89% Fe.

Total polyphenol quantitation using integrated NIR and MIR spectroscopy: A case study of Chinese dates (Ziziphus jujuba)

INTRODUCTION

Polyphenols are the foremost measure of phytochemicals in Chinese dates due to their many potential health benefits such as averting cancers, reducing the risk of coronary artery disease, diuretic activity, myocardial stimulant, coronary dilator and muscle relaxant.

OBJECTIVE

To quantitate the polyphenols in Chinese dates using a data fusion approach with near-infrared (NIR) and mid-infrared (MIR) spectroscopy.

MATERIAL AND METHODS

A total of 80 Chinese dates samples were used for data acquisition from both NIR and MIR spectroscopy. The efficient spectral intervals were extracted by the synergy interval partial least square (Si-PLS) algorithm as input variables for NIR-MIR fusion model. A genetic algorithm (GA) was used to construct the model based on NIR-MIR fusion. The performance of the developed models was evaluated using correlation coefficients of calibration (R² ) and prediction (r² ), root mean square error of prediction (RMSEP), bias and residual prediction deviation (RPD).

RESULTS

The data fusion model based on the GA was superior compared to NIR and MIR build model. The optimal GA-fusion model yielded R²  = 0.9621, r²  = 0.9451, RPD = 2.44, calibration set bias = 0.004 and prediction set bias = 0.061, computing only 15 variables.

CONCLUSION

These findings reveal that integration of NIR and MIR is possible for the prediction of total polyphenol content in Chinese dates.

Influence of Ultrasonic Pretreatment with Hot Air Drying on Nutritional Quality and Structural Related Changes in Dried Sweet Potatoes

The drying of sweet potatoes not only helps to prolong its storage life but the dried form reportedly enriched with high bioactive compounds than regular sweet potatoes. The study aims to investigate the influence of dual-frequency ultrasound pretreatments (40 and 60 kHz) at two different hot air drying temperatures (70 °C and 80 °C) on quality of dried product. Ultrasound pretreatment at 40 kHz with 70 °C maintained the phytochemical compounds in the dried sweet potatoes. Ellagic acid and chlorogenic acid were found as predominant phenolic acids using HPLC analysis, while identification of two new bioactive compounds quercetin-3-rhamnoside and quercetin 3-β-D-glucoside were the novel finding of the current study. A short new band appeared in FTIR in all treatments from 2164 to 2041 cm−1 which refers to C = C alkenes functional group. The multivariate analysis showed a great influence of USH3 and USH1 with a positive relationship with most of bioactive compounds.

Rapid Determination of Active Compounds and Antioxidant Activity of Okra Seeds Using Fourier Transform Near Infrared (FT-NIR) Spectroscopy

Okra seeds (OSD) have been proved to possess significantly anti-fatigue activity and due to their high contents of flavonoids and polyphenols. While, the quality of OSD is easily affected by harvest time, region and other factors. In this research, the rapid method based on Fourier transform near infrared (FT-NIR) spectroscopy was developed for quality assessment of okra seeds. Firstly, 120 samples' spectra were acquired, and quantification of isoquercitrin, quercetin-3-O-gentiobioside, total phenols (TP) and antioxidant assays including 1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, ferric reducing antioxidant power (FRAP) were conducted. Next, partial least squares (PLS) regression and full cross-validation were applied to develop calibration models for these data, and external validation was used to determine models' quality. The coefficient of determination for calibration ( R c 2 ), the root mean square error of cross validation (RMSECV) and the corresponding determination coefficients for cross-validation ( R cv 2 ) proved all these models have excellent precision. Besides, the residual predictive deviation (RPD) of models (4.07 for isoquercitrin, 4.04 for quercetin-3-O-gentiobioside, 9.79 for TP, 4.58 for DPPH and 4.12 for FRAP) also demonstrated that these models possessed good predicative ability. All these results showed that FT-NIR spectroscopy could be used to rapidly determine active compounds and antioxidant activity of okra seeds.

Effect of Winemaking on the Composition of Red Wine as a Source of Polyphenols for Anti-Infective Biomaterials

Biomaterials releasing bactericides have currently become tools for thwarting medical device-associated infections. The ideal anti-infective biomaterial must counteract infection while safeguarding eukaryotic cell integrity. Red wine is a widely consumed beverage to which many biological properties are ascribed, including protective effects against oral infections and related bone (osteoarthritis, osteomyelitis, periprosthetic joint infections) and cardiovascular diseases. In this study, fifteen red wine samples derived from grapes native to the Oltrepò Pavese region (Italy), obtained from the winemaking processes of “Bonarda dell’Oltrepò Pavese” red wine, were analyzed alongside three samples obtained from marc pressing. Total polyphenol and monomeric anthocyanin contents were determined and metabolite profiling was conducted by means of a chromatographic analysis. Antibacterial activity of wine samples was evaluated against Streptococcus mutans, responsible for dental caries, Streptococcus salivarius, and Streptococcus pyogenes, two oral bacterial pathogens. Results highlighted the winemaking stages in which samples exhibit the highest content of polyphenols and the greatest antibacterial activity. Considering the global need for new weapons against bacterial infections and alternatives to conventional antibiotics, as well as the favorable bioactivities of polyphenols, results point to red wine as a source of antibacterial substances for developing new anti-infective biomaterials and coatings for biomedical devices.

Application of NIR and MIR spectroscopy for rapid determination of antioxidant activity of Radix Scutellariae from different geographical regions

INTRODUCTION

The beneficial health effects of traditional Chinese medicines are often attributed to their potent antioxidant activities, usually established in vitro. However, these wet chemical methods for determining antioxidant activities are time-consuming, laborious, and expensive.

OBJECTIVES

This study was conducted to establish a rapid determination of antioxidant activity of Radix Scutellariae using near-infrared (NIR) and mid-infrared (MIR) spectroscopy.

MATERIAL AND METHODS

Antioxidant capabilities were evaluated using 2,2-diphenyl-1-picrylhydrazyl hydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays. The total flavonoid contents (TFCs) of Radix Scutellariae were measured by the aluminium chloride colorimetric method. The same sample was then scanned using NIR and MIR spectroscopy. Chemometrics analysis using partial least-squares (PLS) regression was performed to establish the models for predicting the antioxidant activities of Radix Scutellariae.

RESULTS

A better predictive performance was achieved using PLS models based on NIR data. The determination coefficient (R(2)) and the residual predictive deviation (RPD) for the validation set were 0.9298 and 2.84 for DPPH, and 0.9436 and 2.66 for TFCs, respectively. MIR-PLS algorithms gave a slightly lower reliability (R(2) = 0.9090 and 0.9374, RPD = 2.01 and 2.42, for DPPH and TFC, respectively). Very comparable results for ORAC were obtained with the two methods.

CONCLUSION

The developed spectroscopic method can be successfully applied in high-throughput screening of the antioxidant capability of Radix Scutellariae samples. It can also be a viable and advantageous alternative to laborious chemical procedures.