Addition Of Citric Acid Research Articles

Organosolv Treatment of Red Grape Pomace for Effective Recovery of Antioxidant Polyphenols and Pigments Using a Ternary Glycerol/Ethanol/Water System under Mild Acidic Conditions.

The purpose of this investigation was (i) the development of a novel, green tertiary solvent system, composed of water, ethanol and glycerol, and (ii) the implementation of an organosolv treatment of red grape pomace (RGP) for the efficient production of polyphenol-containing extracts with enhanced antioxidant properties. The treatment developed was performed under mild acidic conditions, imparted by the addition of citric acid, and it was first evaluated on the basis of severity, establishing linear models that described the correlation between treatment performance and combined severity factors. To solicit treatment optimization, response surface methodology was implemented, considering solvent acidity and residence time as the treatment variables. The optimized treatment afforded maximum total polyphenol (166 ± 6 mg GAE g-1 DM), total pigment (4.4 ± 0.2 mg MvE g-1 DM) and total flavanol (31.5 mg CtE g-1 DM) yields and extracts with particularly enhanced antioxidant activity. This might be attributed to specific constituents with high antioxidant potency, such as catechin, determined in the extract using high-performance liquid chromatography. Thus, the treatment developed is proposed as a highly efficient process to generate RGP extracts enriched in polyphenolic compounds, with enhanced antioxidant activity. Such extracts might then be valorized as food additives, to provide antioxidant protection and/or pigmentation.

Effect of pre‐treatments on quality and storage stability of turmeric rhizome candy

SummaryTurmeric rhizome candy, a phytonutrient‐rich shelf‐stable dehydrated and microbiologically stable product was prepared by variation in thermal processing (blanching) and citric acid treatments. It was stored for a period of 90 days and evaluated at an interval of 30 days for chemical, organoleptic, optical, bioactive and textural attributes. FTIR confirmed the significant impact of pre‐treatments on the bioactive compounds of fresh candy. Hardness of the candy increased with decrease in moisture content during storage. Vitamin C, curcumin and total phenols were retained well in the candies up to 90 days of storage study. Addition of citric acid during processing resulted in reduction of hardness and better colour retention. Index of acceptability was maximal for the candy prepared after pre‐treatment T4 (Blanching‐20 min + citric acid 2%). Thus, this investigation can impart the medicinal properties of turmeric in the form of healthy confectionery with good acceptability among consumers.

Role of citric acid in enhancing aromatic hydrogenation performance in Ni-HPW/SiO2 catalysts

In this study, we utilized a sol-gel method to prepare Ni-HPW/SiO2 catalysts with varying citric acid (CA):Ni molar ratios ranging from 0 to 5.0. The catalysts demonstrated different levels of activity in the hydrogenation of ethylbenzene, which correlated to their respective CA:Ni ratios. Introducing citric acid in the preparation process of nickel-based catalysts yielded mesopore formation and reduced NiO particle size, producing a more uniform NiO dispersion on SiO2, which was confirmed by BET, XRD, and TEM analyses. The results of H2-TPR, H2-TPD, NH3-TPD, and Py-IR analyses suggested that the addition of citric acid augmented the interaction between phosphotungstic acid (HPW), Ni species, and SiO2. Citric acid improved Ni species and HPW dispersion, fostering increased HPW-Ni species formation. This, in turn, generated additional electron-deficient Ni ions, stemming from semi-reduced HPW-Ni species, which acted as Lewis acid sites, enhancing Ni+ species effectiveness in activating aromatic rings. The better-dispersed, non-HPW-bound NiO, which, upon complete reduction to Ni, led to a substantial rise in H2 bond cleavage, thereby facilitating more hydrogen spillover. Overall, the infusion of citric acid into fabricating Ni-HPW/SiO2 catalysts sparked a significant surge in their aromatic hydrogenation ability.

Effects of dietary citric acid on growth performance, mineral status, body and muscle composition, muscle growth and mTOR signaling in yellow catfish Pelteobagrus fulvidraco fed with low-manganese diets

The positive impacts of dietary citric acid (CA) on aquaculture species have been studied. However, the wide application of CA in aquatic-feed requires a comprehensive understanding of its nutritional functions. Here, an 8- week feeding trial was performed to determine whether dietary CA supplementation could improve manganese (Mn) utilization and thus reduce Mn excretion by investigating the effect of dietary CA on growth performance, mineral statues, body and muscle composition, muscle growth and mTOR signaling of yellow catfish Pelteobagrus fulvidraco fed with low-manganese (L-Mn) diets. Four isonitrogenous and isolipidic diets were formulated and fed to triplicated groups of fish. A suitable Mn diet containing 5.7 mg kg−1 Mn was set as the control, while the diets without extra Mn addition was regarded as L-Mn group. The other two diets were supplemented with 30 g kg−1 CA into the control and L-Mn diet, respectively. The results showed that the weight gain, specific growth rate, feed efficiency, protein content in muscle, iron concentration in serum, and Mn content in whole body and muscle were significantly decreased after L-Mn diet and resumed by dietary CA addition (P < 0.05). Dietary low-Mn markedly decreased the diameters of muscle fibers, which was alleviated by CA supplementation. Dietary Mn and CA interacted to affect the density of the muscle fiber density, the mRNA expression of muscle development-, myocyte myogenic and myocyte enhancer factors-related genes (P-interaction <0.05). Besides, expression of genes in muscle involved in mTOR signaling including mtor, s6 and eif4e were significantly down-regulated in fish fed L-Mn diet compared to the control. CA supplementation reversed the L-Mn diet induced decrease of their mRNA levels. Furthermore, the protein expression of p-mTOR, S6 and p-S6 were significantly decreased after L-Mn diet, and were upregulated by CA supplementation in the muscle (P < 0.05). Taken together, this study revealed that CA as a feed additive could improve growth performance, mineral bioavailability, muscle growth and protein synthesis in yellow catfish under the condition of Mn deficiency. These positive effects may be partially attributed to dietary CA supplementation improving Mn absorption and bioavailability. This study also has a significance for the development of environmentally friendly feeds for the aquatic species.

A comparative study on the effects of fungal and bacterial phytase with or without citric acid on growth performance, serum mineral profile, bone quality, and nutrient retention in broilers.

Current research aimed to compare the effects of fungal and bacterial phytase with or without citric acid (CA) on growth performance, serum mineral profile, bone quality, and nutrient retention in birds given non-phytate phosphorus (nPP)-deficient diets. A total of 216 Indian River broiler chicks were disturbed into six groups, namely, i) positive control (PC), ii) negative control (NC) contained 0.2% lower nPP than that in the PC diet, iii) NC + fungal phytase (Aspergillus niger), iv) NC + fungal phytase with 2% CA, v) NC + bacterial phytase (Escherichia coli), and vi) NC + bacterial phytase with 2% CA. Compared to the PC group, the NC group showed poor performance, serum phosphorus (P) content, P retention, and bone quality. However, with the inclusion of phytase, all these phenomena were improved. The addition of bacterial phytase showed better values compared with fungal phytase. The main effects of phytase were significant for the feed conversion ratio (FCR), metabolizable energy conversion ratio (MECR), and P retention. The addition of CA, either with fungal or bacterial phytases, did not show considerable beneficial effects on overall performances. However, the main effects of CA were significant on the FCR, MECR, and crude protein conversion ratio. Incorporating bacterial and fungal phytase into low-nPP diets enhanced the broiler's performance. The effects of bacterial phytase were more apparent than those of fungal phytase. However, the efficacy of phytase based on the source might relate to dose, and other factors need further investigation.

Citric acid–enhanced Fe2+ and Cu2+ synergistic activation of persulfate for rhodamine B degradation

Citric acid (CA) and Cu2+ were used to enhance Fe2+-activated persulfate (PDS) for rhodamine B (RhB) oxidative degradation. The effects of PDS concentration, Fe2+ concentration, CA concentration, Cu2+ concentration, pH, and common inorganic anions in water on PDS activation and RhB degradation were investigated. Results showed that sulfate and hydroxyl radicals were the primary active substances in the reaction system, with sulfate radical playing a key role. The addition of CA and Cu2+ improved the efficiency of RhB decomposition, achieving a removal rate of 98.4% after 30 min of reaction, governed by pseudo-first-order. The presence of a complexing agent, allows effective RhB removal over a wide pH range. The free sulfate radical (SO4·−) concentration increases with increasing Fe2+ concentration. However, when the Fe2+ concentration was higher than 0.5 mM, self-quenching of SO4·− occurred and the RhB degradation rate decreased. In contrast, with increasing PDS concentration, the degradation rate of RhB continued to increase. The radical process was the main mechanism of RhB decomposition. Analysis of intermediates showed that C–C and C–N bond cleavage was the most likely degradation mode for contaminants to become small molecules.

Betanin dye extracted from ayrampo (Opuntia soehrensii) seeds to develop dye-sensitized solar cells.

Pigments extracted from ayrampo seeds of the Peruvian-native prickly pear (Opuntia soehrensii) were used in dye-sensitized solar cells with promising efficiencies. The performance of the solar cells was then improved via the addition of citric acid to stabilise the photosensitive dye, and an efficiency of 1.41% was achieved with current output remaining stable after 7 days. Upon testing in low-light conditions, the solar conversion efficiency of devices increased to 4%. This paper not only highlights the potential of natural sensitizers in DSSCs but also shows that simple extraction and gentle handling methods can contribute to the device performance.

Modification of Polyethylene Glycol and Citric Acid on Palm Fiber Waste Nanofibers on the Adsorption of Violet Crystal Dyes

&lt;p&gt;This study developed nanofibers derived from sugar palm fiber waste, incorporating citric acid and polyethylene glycol (PEG) modifications to adsorb crystal violet (CV) dye. The synthesis process involved alkalization-acid hydrolysis and bleaching techniques. Subsequent analyses of nanofiber characteristics were conducted using Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX). The efficacy of these modified nanofibers in adsorbing CV was quantitatively measured using an Ultraviolet-Visible (UV-Vis) spectrophotometer. The study successfully synthesized nanofibers from sugar palm fiber waste with modifications: PEG-modified nanofibers (NP 2 and NP 24) and citric acid-modified nanofibers (NS 2 and NS 24). These modifications resulted in nanofibers with a smooth, white texture. FTIR analysis of the samples (N, NP 2, NP 24, NS 2, and NS 24) revealed the presence of functional groups essential for cellulose, specifically -OH, C-H, and C-O groups. The addition of citric acid introduced a new group, C=O, albeit with very weak intensity. PEG modifications were evident from the stretching observed in the -OH groups. SEM analysis confirmed the presence of a layer on the nanofibers, attributed to citric acid (NS 2 and NS 24) and PEG (NP 2 and NP 24). XRD results indicated that the pre-and post-modification nanofibers exhibited a semi-crystalline phase. The adsorption mechanism was predominantly guided by Van der Waals electrostatic interactions between the absorbent material and the adsorbate. Intriguingly, the citric acid and PEG modifications did not significantly alter the adsorption outcomes. The adsorption capacity remained stable over time, as evidenced by measurements of 0, 15, 30, 45, 60, 90, and 120 minutes.&lt;/p&gt;

Rapid Detection of Adulteration in Boswellia Extracts with Citric Acid by UPLC–HRMS and 1H NMR

Boswellia serrata ole-gum-resin extracts (BSEs) are commonly used as food supplements, especially in osteoarthritis management. The quality standard is established by determining 11-keto-β-boswellic acid (KBA) and acetyl-11-keto-boswellic acid (AKBA) content using high-performance liquid chromatography (HPLC) or assessing the total boswellic acid (TBA) content by titrimetry. The limited geographical distribution of Boswellia species and increasing industrial demand could increase the risk of adulteration in Boswellia-containing products. In this study, 14 BSEs from commercial sources, used in food supplements, were analyzed in comparison with a USP Reference Standard extract. The KBA and AKBA content was determined by HPLC, whereas the TBA content was determined by titration. Targeted UHPLC-high-resolution mass spectrometry (HRMS) was applied to identify the carboxylic acid content in the samples. The 1H NMR spectra of extracts were also analyzed. Only two products met the criteria for KBA and AKBA content. Although, the TBA content complied with the expected amount, 10 extracts contained citric acid levels of 6–11% even though citric acid is not a cha­racteristic component of BSEs. Our results suggest undeclared addition of citric acid to comply with declared contents of TBA when using titration methods. Incorporation of citric acid to industrial samples – in order to alter the outcomes of the titration analysis – was demonstrated for the first time.

Enhancement of norfloxacin degradation by citrate in S-nZVI@Ps system: Chelation and FeS layer

The degradation of organic pollution by sulfur-modified nano zero-valent iron(S-nZVI) combined with advanced oxidation systems has been extensively studied. However, the low utilization of nZVI and low reactive oxygen species (ROS) yield in the system have limited its wide application. Herein, a natural organic acid commonly found in citrus fruits, citric acid (CA), was combined with the conventional S-nZVI@Ps system to enhance the degradation of norfloxacin (NOR). The addition of CA increased the NOR removal by about 31% compared with the conventional S-nZVI@Ps system under the same experimental conditions. Among them, the enhanced effect of CA is mainly reflected in its ability to promote the release of Fe2+ and accelerate the cycling of Fe2+ and Fe3+ to further improve the utilization of nZVI and the generation of ROS; it also promotes the dissolution of the active substance (FeS) on the surface of S-nZVI to further improve the degradation rate of NOR. More importantly, the chelate of CA and Fe2+ (CA-Fe2+) had higher reactivity than alone Fe2+. Free radical quenching and electron spin resonance (ESR) experiments indicated that the main ROS for the degradation of NOR in the CA/S-nZVI@Ps system were SO4•- and OH•. CA-bound sulfur-modifying effects on NOR degradation was systematically investigated, and the degradation mechanism of NOR in CA/S-nZVI@Ps system was explored by various techniques. Additionally, the effect of common anions in water matrix on the degradation of NOR in CA/S-nZVI@Ps system and its degradation of various pollutants were also studied. This study provides a new perspective to enhance the degradation of pollutants by S-nZVI combined with advanced oxidation system, which can help to solve the application boundary problem of S-nZVI.

Influence of time-temperature in the antioxidant activity, anthocyanin and polyphenols profile, and color of Ardisia compressa K. extracts, with the addition of sucrose or citric acid

The objective of this study was to analyze and optimize the influence of heating time and citric acid (CA) or sucrose addition of Ardisia compressa K. extracts on phenolic compounds (TPC), monomeric anthocyanins (MAA), antioxidant activity (TAC), color density (CD), and hue tint (HT), using a full factorial design. Extractions were performed: temperature (25, 50, or 70 °C), time (15, 30, 60, or 90 min), CA (0.0 or 0.02 g), and sucrose (0.0 or 5.0 g). HPLC-DAD-ESI-MS was conducted in extracts without additives and with the addition of CA (0.02 g) or sucrose (5.0 g), at 25, 50, or 70 °C for 15 min. CA-added extracts showed maximum TPC, MAA, TAC (DDPH and ABTS assays), and CD values, with the lowest HT values. Malvidin 3-O-galactoside and myricetin-O-hexoside were the predominant anthocyanin and non-anthocyanin polyphenols. Time, temperature, and solute influenced the optimized extraction of TPC, MAA, anthocyanins, TAC, CD, and HT.

Citric acid and temperature programming assisted synthesized Vanadium Silicate-1 for oxidative desulfurization of dibenzothiophene

Vanadium-MFI zeolites possess phenomenal potential for catalytic oxidation, while their application is constrained by vanadium content and species distribution. Here, we constructed Vanadium Silicate-1 (VS-1) with enhanced content and preferable distribution by the addition of citric acid in tandem with a temperature-program strategy. Citric acid could modulate the pH in the initial gel and coordinate with vanadium, inhibiting the hydrolysis of vanadium and promoting vanadium incorporation. Moreover, a temperature program was employed to generate unsaturated silicon species, overcoming the tendency of aggregation in vanadium precursor and further promoting vanadium insertion. Furthermore, the effects of the first-stage crystallization temperature and time on the properties of zeolite have been investigated in detail. The sample synthesized through the optimal temperature program achieved 99.9 % dibenzothiophene conversion in 2 h, 10.4 times that of conventional synthesis. To explain the excellent reaction activity, the relationship between different vanadium species and reaction results was investigated. Through linear fitting, V=O(OSi)2(OH) was considered as the dominant active species in oxidative desulfurization (ODS) reaction. Notably, the recycled zeolite proved good reusability, further enhancing its promising application prospect.

Novel cross-linking of toxic-free biopolymers for cellulose-gelatin films from avocado seed waste

Renewable, low-cost, and environmentally friendly processes have been continuously developed to produce biopolymers for various functional materials. This study aims to develop cellulose-gelatin film as a toxic-free biopolymer. Combining the excellent properties of cellulose and gelatin offers a promising alternative for improving the desirable properties. Herein, avocado seed waste was chemically treated and used as a cellulose-rich filler for gelatin-based film synthesis. Furthermore, different influences were examined with- and without- citric acid addition as a cross-linker agent. The citric acid cross-linked film has cellulose trapped in gelatin matrix structure with a smooth surface, good elasticity, sufficient flexibility, and free-toxic substance. Moreover, this study demonstrated that citric acid cross-linking design successfully improved the percent elongation film from 2.47 to 68.04 %, enhanced the water absorption capacity to 99.71 % at 24 h, and revealed high antibacterial activity, implying potential future application, especially for wound dressing.

Enhanced catalytic performance for methane dehydro‐aromatization on Mo/HMCM‐49 prepared with citric acid

AbstractA simple citric acid (CA)‐ammonium molybdate co‐impregnation method was applied to prepare the Mo‐based MCM‐49 catalyst to ameliorate the dispersion of metallic Mo for methane dehydro‐aromatization reaction (MDA). The newly prepared catalyst has higher crystallinity and maintains the original morphology of zeolite, which proves that the addition of citric acid will not destroy the basic structure of the catalyst. Based on H2‐TPR, UV‐vis, NH3‐TPD and XPS characterization results, it can be corroborated that the introduction of citric acid changes the coordination state of Mo element. Brønsted acid sites can stabilize the monomeric Mo oxide species by increasing MoOx migration into the MCM‐49 zeolite pores channel after calcination, which may affect the distribution of active sites MoCx and thus improve MDA catalytic activity. The experimental results show that the Mo‐based MCM‐49 catalyst with nCA : nMo ratios of 1.0 has higher methane conversion (14.5 %) and aromatics yield (9.8 %). The combination of XPS, TG and Raman tests of the spent catalyst confirms that the newly synthesized catalysts produce less carbon deposition, thus improving the catalytic durability during the MDA reaction.

Development of lightweight, high-strength, and highly porous ligno-nanocellulosic foam with excellent antioxidant and insulation properties

This study reports an environmentally friendly ligno-nanocellulosic foam prepared by utilizing lignin (LGN), cellulose nanofiber (CNF), and citric acid (CA) as a green crosslinker through an easy, low-cost, and environmentally friendly process. The FTIR study and XPS analysis of the prepared LGN/CNF foams confirm the crosslinking between the components, which leads to lower shrinkage, lower density, and higher porosity than the neat CNF foam, achieving a remarkably low density of 19.59 mg/cm3 and high porosity of 98.84 % The morphology and microstructure of the foam show a uniform three-dimensional porous network built by strong cell walls. The crosslinked LGN/CNF foams indicate 182 % higher compressive modulus and 306 % higher compressive strength at 70 % strain than the neat CNF foam. Further, the addition of LGN and CA enhances the antioxidant activity of the foam. The prepared foam shows lower thermal conductivity and better sound absorption performance than the neat CNF foam, indicating a potential to be used as thermal insulation and sound-absorbing materials that can mitigate greenhouse gas emissions.

Construction of Ni/C composites with double-shell hollow porous structure toward high-efficiency microwave absorption

Designing structure at the nanoscale of materials has been proved to be an effective way to control electromagnetic parameters and optimize microwave absorption performance. For constructing lightweight microwave absorption materials, abundant studies focus on the preparation of absorbent with hollow, porous or yolk-shell structure. However, it is still a challenge to integrate multiple structures on one material by simple method. In this work, we found that the addition of citric acid in the preparation process played an extremely important role in regulating the structure of Ni-MOF, and developed one-step approach to synthesis double-shell hollow porous Ni-MOF. After the carbonization process, the Ni/C composite was obtained. The controllable morphology of Ni-MOF endowed Ni/C composite adjustable absorbing properties. Under the assistance of citric acid, the Ni/C composite with yolk-shell, porous, as well as double-shell hollow porous structure was also synthesized. The optimal reflection loss was −56.18 dB, the broadest bandwidth was 6.1 GHz at 2.2 mm for double-shell hollow porous Ni/C composite. Particularly, strong reflection loss at C band, X band, and Ku band was realized by regulating the structure of Ni/C composite. This work revealed the mechanism of microstructures regulating the absorbing properties, which could be beneficial to the further development of MOFs derived absorbent.

Dietary citric acid improves growth performance, feed utilization, phosphorus utilization, lateral scute hardness, and duodenal microstructure in juvenile hybrid sturgeon (Acipenser baerii ♀ × A. schrenckii ♂)

This study was performed to evaluate the feasibility of using citric acid (CA) as a feed supplement to improve phosphorus (P) utilization by juvenile hybrid sturgeon (19.75 ± 0.13 g). Four isophosphoric (1.00% total P) diets containing 0.5%, 1.0%, 2.0%, 4.0% CA were formulated (1.0% P-0.5% CA, 1.0% P-1% CA, 1.0% P-2% CA, 1.0% P-4% CA). A normal P (1.00% total P) diet and a high P (1.40% total P) diet without CA addition were designed as a negative control (1.0% P-0% CA) and a positive control (1.4% P-0% CA), respectively. A commercial diet (1.48% total P) was applied as a reference group (1.4% P-commercial). The seven diets were randomly allocated to 21 tanks with 15 fish per tank. The fish were hand fed to apparent satiation three meals daily for 8 weeks. The results manifested that significantly improved growth performance (final body weight, weight gain rate) and feed utilization (feed conversion ratio, protein efficiency ratio) were discovered in 1.0% P-0.5% CA group compared with two control groups. The P contents in dorsal muscle, vertebrae, and serum were significantly higher in 1.0% P-1% CA group compared with negative control. Additionally, the P retention rate in 1.0% P-0.5% CA and 1.0% P-1% CA groups were significantly higher than 1.4% P-0% CA group. Dietary addition of 0.5% and 1.0% CA significantly improved hardness of lateral scute compared with negative control. Compared with the negative control, the serum alkaline phosphatase activity was significantly improved by addition of 0.5% and 1.0% CA. Supplementation with 0.5% CA significantly elevated duodenal micromorphology (villi height, muscularis thickness, lamina propria width) compared with negative control. The duodenal type IIa sodium phosphate cotransporter (NaPi-IIa) mRNA level was significantly up-regulated by addition of 1.0% CA compared with two control groups. In a nutshell, CA could be a suitable feed supplement in sturgeon diet and dietary supplementation of 0.5% CA improved growth performance, feed utilization, P utilization efficiency, lateral scute hardness, and duodenal micromorphology.

Performance characterization of water extracts of Camellia oleifera cake/sodium N-lauroylsarcosinate foam detergent with high foamability

In this study, we hypothesized that an environment-friendly foam detergent with synergistic effects could be synthesized from saponins-rich water extracts (WE) of Camellia oleifera cake, sodium N-lauroylsarcosinate (SLS), citric acid (CA), and ethanol. The ratio of WE and SLS was optimized by comparing the foam properties and cleaning efficiency. The synergistic effect was elucidated by viscosity, surface tension, zeta potential, contact angle, and particle size. The effects of ethanol and CA on the foam properties and cleaning efficiency were also studied, and the potential mechanism was analyzed. The results showed that SLS-WE (3−1) with the strongest foamability had the highest cleaning efficiency (82.8%) for olive oil. This is related to the synergistic effects of surface activity between WE and SLS. The addition of WE improved the foam elasticity and yield stress of the mixture system, thus preventing secondary contamination. The addition of CA (0.1 wt%), ethanol (3.7 wt%), and CA/ethanol (0.1/3.7 wt%) improved the foamability with no negative effect on foam stability. The cleaning efficiency of foam detergent reached 93.7% under the mixture of CA and ethanol. The SLS-WE (3−1) system improved the oil imbibition of foam by reducing surface tension and bubble size. Moreover, the SLS-WE (3−1) foam had a strong wiping motion. Ethanol and citric acid increased cleaning efficiency by improving imbibition and wiping, respectively. The environmentally friendly foam detergent fabricated in this research exhibited high foamability, stability, and cleaning efficiency.

Addition of Organic Acids to Base Wines: Impacts on the Technological Characteristics and the Foam Quality of Sparkling Wines.

Climate change is causing a significant decrease in the total acidity of grapes and related wines. This represents a serious issue for sparkling wine production. Consequently, before the second fermentation, the acidification of base wines is often necessary. However, the impacts of the most important organic acids on the foam properties of sparkling wines are not yet well known. The impacts of the addition of tartaric, malic, citric, and lactic acid on the quality of Falanghina and Bombino sparkling wines were evaluated. Analyses were performed soon after the second fermentation and one year after aging sur lees. The addition of each different organic acid to the two base wines resulted in significant changes in the sparkling wines not only in terms of pH, titratable acidity, and buffering capacity but also in the content of total amino acids and, in some cases, in the height of the foam and its stability over time. For both grape varieties, acidified wines showed a lower content of total amino acids in comparison with the control wines. The addition of lactic acid determined a higher persistency of the foam even after one year of aging sur lees only in Falanghina wines. The results obtained herein highlight the importance of organic acids and the pH of the base wines for the content of amino acids in sparkling wines. No strict correlation between organic acid addition and the foamability of wines was observed.

The Impact of Solvent Composition and Copper (Cu) Ion Doping on Dye Anthocyanin on Increasing Dye-Sensitized Solar Cell (DSSC) Efficiency

&lt;p class="AbstractText"&gt;The development of Dye Sensitized Solar Cells (DSSC) is increasing fast because fabrication costs are more affordable than silicon solar cells. In this study,&lt;em&gt; anthocyanin pigments&lt;/em&gt; were used as a natural dye source. Anthocyanins are a group of flavonoids that can be extracted most proficiently in acidic conditions; therefore, variations in the composition of solvents and acids significantly impact anthocyanin yield. The anthocyanin pigments in this study were extracted from dragon fruit peels using a maceration method with variations in methanol composition and the addition of hydrochloric acid or citric acid (3/0; 3/0.5; 3/1). This study aims to improve the efficiency of DSSC by varying the solvent composition and adding Cu ion doping. The characterizations include measurement of absorbance, functional group, and efficiency using UV-Vis Spectrophotometer, Fourier Transform Infrared (FTIR), and current-voltage, respectively. The results show that anthocyanin dye with a composition of methanol/acid (3/0) and the addition of Cu ion produced the highest absorbance value and efficiency of 0.4102 Ω&lt;sup&gt;-1&lt;/sup&gt;m&lt;sup&gt;-1&lt;/sup&gt; and 0.016%, respectively.&lt;/p&gt;