Rapid determination of simple polyphenols in grapes by HPLC using a monolithic column

The development of a rapid, reliable and reproducible LC method for the determination and quantification of 13 polyphenols (gallic acid, protocatechuic aldehyde, gentisic acid, catechin, vanillinic acid, caffeic acid, vanillin, epicatechin, syringaldehyde, p-coumaric acid, ferulic acid, sinapic acid and resveratrol) in grapes and derived products is reported

Assessing the Effect of Intensive Agriculture and Sandy Soil Properties on Groundwater Contamination by Nitrate and Potential Improvement Using Olive Pomace Biomass Slag (OPBS)

Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/ 4.0/). -- (This article belongs to the Special Issue Biomass—a Renewable Resource for Carbon Materials)The relationship between agricultural activities, soil characteristics, and groundwater quality is critical, particularly in rural areas where groundwater directly supplies local people. In this paper, three agricultural sandy soils were sampled and analyzed for physicochemical parameters such as pH, water content, bulk density, electrical conductivity (EC), organic matter (OM), cation exchange capacity (CEC), and soil grain size distribution. Major and trace elements were analyzed by inductively coupled plasma-optical emission spectrometry (ICP/OES) to determine their concentrations in the fine fraction (FF) of the soils. Afterward, the elemental composition of the soils was identified by X-ray powder diffraction (XRD) and quantified by X-ray fluorescence (XRF). The surface soil characteristics were determined by the Brunauer–Emmett–Teller (BET) method, whereas the thermal decomposition of the soils was carried out using thermogravimetric analysis and differential scanning calorimetric (TGA-DSC) measurements. The morphological characteristics were obtained by scanning electron microscopy (SEM). Afterward, column-leaching experiments were conducted to investigate the soil’s retention capacity of nitrate (NO−3). Parallelly, a chemical and physical study of olive pomace biomass slag (OPBS) residue was carried out in order to explore its potential use as a soil additive and improver in the R’mel area. The OPBS was characterized by physicochemical analysis, assessed for heavy metals toxicity, and characterized using (XRD, XRF, SEM, and BET) techniques. The results show that the R’mel soils were slightly acidic to alkaline in nature. The soils had a sandy texture with low clay and silt percentage (<5% of the total fraction), low OM content, and weak CEC. The column experiments demonstrated that the R’mel irrigated soils have a higher tendency to release large amounts of nitrate due to their texture and a higher degree of mineralization which allows water to drain quickly. The OPBS chemical characterization indicates a higher alkaline pH (12.1), higher water content (7.18%), and higher unburned carbon portion (19.97%). The trace elements were present in low concentrations in OPBS. Macronutrients in OPBS showed composition rich in Ca, K, and Mg which represent 10.59, 8.24, and 1.56%, respectively. Those nutrients were quite low in soil samples. Both XRD and XRF characterization have shown a quasi-dominance of SiO2 in soil samples revealing that quartz was the main crystalline phase dominating the R’mel soils. Oppositely, OPBS showed a reduced SiO2 percentage of 26,29% while K, Ca, and P were present in significant amounts. These results were confirmed by XRF analysis of OPBS reporting the presence of dolomite (CaMg, (CO3)2), fairchildite (K2Ca (CO3)2), and free lime (CaO). Finally, the comparison between the surface characteristic of OPBS and soils by BET and SEM indicated that OPBS has a higher surface area and pore volume compared to soils. In this context, this study suggests a potential utilization of OPBS in order to (1) increase soil fertility by the input of organic carbon and macronutrients in soil; (2) increase the water-holding capacity of soil; (3) increase soil CEC; (4) stabilize trace elements; (5) enhance the soil adsorption capacity and porosity

Optimization of the Microwave-Assisted Extraction of Simple Phenolic Compounds from Grape Skins and Seeds

A method for the extraction of phenolic compounds from grape seeds and skins using microwave-assisted extraction (MAE) was developed. Optimization of the effects of the extraction parameters in terms of the results of extraction was obtained using the response surface methodology. The parameters studied were extraction solvent (methanol, ethanol, acetone, and water), percentage of methanol in water, quantity of sample in relation to volume of extraction solvent (solid:liquid, 10-50 mg mL(-1)), power (100-500 W), magnetic stirring speed (0-100%), and extraction time (5-20 min). Finally, the repeatability and the intermediate precision of the method were determined. The best conditions proved to be: 65% methanol in water as an optimum extraction solvent; 0.5 g of grape skin or seed in a volume of 25 mL; a power of 500 W with the maximum stirring speed (100%); and an extraction time of 5 min. The phenolic compounds proved to be stable in the optimized extraction conditions. The resulting repeatability and the intermediate precision of the optimized method showed a relative standard deviation below 7%. The new method applied on Napoleon grape allowed for the determination of catechin (453.2 (mg kg(-1))), epicatechin (306.3 mg kg(-1)), caftaric acid (22.37 mg caffeic acid equivalents kg(-1)), dihydrokaempferol-glycoside (11.13 mg kaempferol equivalents kg(-1)), quercetin (18.28 mg kg(-1)), quercetin-3-glucoside (20.09 mg quercetin equivalents kg(-1)), and kaempferol-3-glucoside (11.10 mg kaempferol equivalents kg(-1)).This research was co-financed by the 2014-2020 ERDF Operational Programme and by the Department of Economy, Knowledge, and Business at the University of the Regional Government of Andalusia. Project reference: FEDER-UCA18-108366. Documen

Optimal Design Approach Applied to Headspace GC for the Monitoring of Diacetyl Concentration, Spectrophotometric Assessment of Phenolic Compounds and Antioxidant Potential in Different Fermentation Processes of Barley

The present study aimed to validate a control method on the gas chromatography system (GC) based on the experimental design strategy, to examine the changes and correlation between the fermentation process and the quality of alcoholic and non-alcoholic beer product, especially the formation of diacetyl. On the other hand, spectrophotometric methods were applied to the determination of polyphenols content and the potential antioxidant activity of beer during different fermentation processes. with this aim, three modes of barley fermentation were used, specifically classical fermentation, stopped fermentation and thermal process. The results showed that the different fermentation modes had a major impact on diacetyl production. The highest concentration was obtained using stopped fermentation 0.36 mg/L, the lowest concentration value 0.07 mg/L was detected using the thermal process. Monitoring the increase of oxygen concentration between fermentation, filtration, and filling of the final product (32, 107, 130 ppm, respectively) has a significant impact on the concentration of diacetyl. The obtained results of spectrophotometric analysis showed that the total antioxidant activity changed during beer fermentation process and demonstrate that the extend of the antioxidant activity was very much dependent on the total polyphenolic content with a higher value in Hopped wort (13.41%, 65 mg GAE 100 mL(-1), 28 mg CE 100 mL(-1)) for antioxidant potential, total phenolic content, and total flavonoids content, respectively, whereas the lowest values was detected in Non-alcoholic beer using thermal process (7.24%, 35 mg GAE 100 mL(-1), 10 mg CE 100 mL(-1)) for antioxidant potential, total phenolic contents, and total flavonoids contents, respectively. Based on the results achieved, we reveal the impact of the fermentation process on the nutritional value of the final product

Wild strawberry (Arbutus unedo): Phytochemical screening and antioxidant properties of fruits collected in northern Morocco

The aim of this study was to determine the polyphenolic compounds and the antioxidant ability of Arbutus unedo fruits, collected from three regions of northern Morocco, using high-performance liquid chromatography coupled to diode array and electrospray ionization mass spectrometry detection. The proper extraction method has been selected to achieve this objective. After delipidation, the three harvests were extracted by sonication using two solvents with increased polarity ethyl acetate and MeOH:water, 80:20 (v/v). Total polyphenols, flavonoids, tannins and anthocyanins were respectively: 108.41 ± 9.29 mg GAE/g (w/w) dry weight (DW), 101.07 ± 5.6 mg QE/g (w/w) (DW), 0.45 ± 0.48 mg EC/g (w/w) (DW) and 0.35 ± 0.48 mg Pg-3-glu/g (w/w) (DW). EC50 values for reducing power and DPPH radical scavenging activities were between 1.37 ± 0.2 and 17.82 ± 0.12 µg/mL (w/v). A total of 75 compounds were tentatively identified and some of these had never been found until nowadays in Arbutus unedo. The average amount of antioxidant compounds obtained by semi-quantitative analyses was 120.35 ± 32.05 mg/100 g (w/w) (DW). The attained results clearly highlight the potential of A. unedo as a source of healthy compounds, which could be advantageously added to the daily diet, making it a potential candidate for the cure for many emerging diseases

Profiling the Volatile and Non-Volatile Compounds along with the Antioxidant Properties of Malted Barley

In this work, the stability of antioxidant compounds in malting barley seeds before and after the production of the final products is reported. In this reflection, the findings revealed that the process of fermentation had a significant impact on antioxidant activity. In vitro, antioxidant capacities were evaluated using DPPH free radical scavenging assay. The results obtained from the spectrophotometric analysis showed that the lowest inhibition value was observed in the samples that were obtained by the classical fermentation process (ABC) and the samples of non-alcoholic beer obtained by the thermal process (NABT), with free radical inhibition capacity values of 8.50% and 5.50%, respectively. The samples of hopped wort (HW) and malted barley seeds extract (BSE) showed very high antioxidant activity with free radical inhibition capacity of 14% and 12.60%, respectively. The obtained extracts were analyzed by gas chromatography and high-performance liquid chromatography, both combined with mass spectrometry detection (GC-MS, HPLC-MS). GC-MS analysis of the SPME extraction showed the presence of 29 compounds with isopentyl alcohol in major concentration (18.19%) in the alcoholic beer; on the other hand, the HPLC-DAD-ESI/MS analysis of the ethyl acetate extract showed the presence of 13 phenolic compounds. Interestingly, the degradation of 3-Hydroxyphloretin 2'-O-glucoside in the final products of the non-alcoholic beers was found. Finally, the FTIR analysis was also employed in order to detect the type of efficient groups present in the extracts

Elucidation of Antioxidant Compounds in Moroccan Chamaerops humilis L. Fruits by GC-MS and HPLC-MS Techniques

The aim of this study was to characterize the phytochemical content as well as the antioxidant ability of the Moroccan species Chamaerops humilis L. Besides crude ethanolic extract, two extracts obtained by sonication using two solvents with increased polarity, namely ethyl acetate (EtOAc) and methanol-water (MeOH-H2O) 80:20 (v/v), were investigated by both spectroscopy and chromatography methods. Between the two extracts, the MeOH-H2O one showed the highest total polyphenolic content equal to 32.7 +/- 0.1 mg GAE/g DM with respect to the EtOAc extract (3.6 +/- 0.5 mg GAE/g DM). Concerning the antioxidant activity of the two extracts, the EtOAc one yielded the highest value (1.9 +/- 0.1 mg/mL) with respect to MeOH-H2O (0.4 +/- 0.1 mg/mL). The C. humilis n-hexane fraction, analyzed by GC-MS, exhibited 69 compounds belonging to different chemical classes, with n-Hexadecanoic acid as a major compound (21.75%), whereas the polyphenolic profile, elucidated by HPLC-PDA/MS, led to the identification of a total of sixteen and thirteen different compounds in both EtOAc (major component: ferulic acid: 104.7 +/- 2.52 mu g/g) and MeOH-H2O extracts (major component: chlorogenic acid: 45.4 +/- 1.59 mu g/g), respectively. The attained results clearly highlight the potential of C. humilis as an important source of bioactive components, making it a valuable candidate to be advantageously added to the daily diet. Furthermore, this study provides the scientific basis for the exploitation of the Doum in the food, pharmaceutical and nutraceutical industries

Impacto del proceso de liofilización en la calidad de las fresas

Este trabajo expone el análisis y la modelación cinética de la deshidratación de las fresas enteras y por sec-ciones, durante el proceso de la liofilización. Fue utilizado un liofilizador Virtis 35L Gardiner. La liofilización se realizó a varias temperaturas de la plancha y para varios gruesos de producto, observándose que el aumento en la temperatura del plato de 30 a 70°C en el curso de la liofilización reduce la duración de este proceso en el caso de las fresas enteras de 48h a 36h y de 12h a 8h en el caso de las secciones, para obtener productos secos estables. El estudio del impacto de diferentes parámetros de la liofilización de las fresas demuestra que la temperatura tiene una incidencia importante en la reducción de la duración del proceso. Esto hace bajar los costos del proceso mientras se preserva la calidad de la fruta seca, abriendo así con el uso de esta tecnología el campo en el tratamiento de los productos alimenticios nuevos

Comparison Study and Assessment of Thermal Performance and Energy Self-sufficiency of Nearly Zero Energy Building (nZEB) in Two Different Climates

The paper presents a comparative study of a nearly zero-energy office building with respect to two different cities located in two different climate zones: a humid continental climate with dry winter, represented by the city of Seoul and a hot semi-arid climate, represented by the city of Benguerir. Obviously, climate is one of the most influential factors affecting indoor thermal comfort, energy demand and energy self-sufficiency of nZEBs. In this study, we first assess the impact of regional climate on the thermal performance, and we explore the influence of the local natural energy sources on the Solar BIPV and PV outputs in the two different cities: Benguerir and Seoul, respectively. And then, we explore the overall energy self-sufficiency of the nZEB for the respective climates. The differences in thermal need and energy self-sufficiency responses were statistically significant. With respect to Benguerir, the thermal energy needs for cooling amount to 71.5 kWh/m²/year, with almost no heating thermal needs and the Energy Balance (EB) reaches 0.88. On the other side, these metrics are around 52.56 kWh/m²/year for the total thermal needs with a share of 43% for heating thermal needs and a yearly EB equals to 0.6 for the nZEB in Seoul. Finally, it is important to mention that the BIPV output share out of the total solar energy output amounts to 57% and 61% for the cities of Seoul and Benguerir, respectively, which highlight the important role of BIPV in reaching advanced levels of energy self-sufficiency

A holistic digital workflow methodology to shifting towards net zero energy urban residential buildings in a semi-arid climate

Given the looming threats of climate change and the rapid worldwide urbanization, it is a necessity to prioritize the transition towards a carbon-free built environment. This research study provides a holistic digital methodology for parametric design of urban residential buildings with regard to the Mediterranean semi-arid climate zone of Morocco in the early design phase. The morphological parameters of the urban residential buildings, namely the buildings’ typology, the distance between buildings, the urban grid’s orientation, and the window-towall ratio, are evaluated in order to identify the key combinations of passive and active solar design strategies that determine the high energy performing configurations, based on the introduced Energy Performance Index (EPI), which is the ratio between solar BIPV production to maximum available installed BIPV capacity and the normalized thermal energy needs. Through an automated processing of 2187 iterations via Grasshopper, we simulate daylight autonomy, indoor thermal comfort and solar rooftop photovoltaic and building integrated photovoltaic (BIPV) energy potential. Then, we analyze the conflicting objectives of energy efficiency measures, active solar design strategies, and indoor visual comfort in the decision-making process that supports our goal of getting closer to net zero urban residential buildings. The digital workflow showed interesting trends in reaching a balanced equilibrium between performance metrics influenced by the contrasting impact of solar exposure on indoor daylight autonomy and thermal energy demand. Furthermore, the study’s findings indicate that it is possible to achieve an annual load match exceeding 66,56 % while simultaneously ensuring an acceptable visual indoor comfort (sDA higher than 0.4). The findings also highlight the important role of the BIPV system in shifting towards the net zero energy goal, by contributing up to 30 % of the overall solar energy output and covering up to 20 % of the yearly self-consumption. Moreover, the energy balance evaluation on an hourly basis indicates that BIPV system notably enhances the daily load cover factor by up to 5.5 %, particularly in the case of slab SN typology, throughout the different seasons. Graphical representations of the yearly, monthly and hourly load matches and the hourly energy balance of the best performing configurations provide a thorough understanding of the potential evolution of the urban energy system over time as a result of the gradual integration of active solar electricity production