Onion Peel Extract Research Articles

Characterization and evaluation of antioxidant potential of onion peel extract of eight differentially pigmented short-day onion (Allium cepa L.) varieties

Outer papery peel of onion bulb is an inevitable bio-waste generated in the course of postharvest handling and processing. Onion peels are rich source of nutraceutically important polyphenolic compounds having many therapeutic potentials. In this study, we characterized onion peel extract (OPE) of eight differentially pigmented short-day onion varieties through ultra-high-performance liquid chromatography coupled with high-resolution single stage Orbitrap spectrometry and evaluated the antioxidant potential. A total of 49 phenolic compounds were identified in this study which include 33 anthocyanin, 8 flavanol, 4 flavones, and 1 each of pyranoanthocyanin, chalcone, phenolic acid, and ellagitannins. Anthocyanin was the most abundant polyphenolic compound followed by flavanol in all the varieties. Among anthocyanin, 10 cyanidin, 10 delphinidin, 4 peonidin, 4 petunidin, 3 pelargonidin, and 2 malvidin were identified. Cyanidin-3-(6-malonylglucoside), delphinidin, and delphinidin-3-galactoside were the predominant pigment in dark red varieties (BDR and BRJ), and its abundance suggests a key role in the differential pigmentation pattern of onion peel. Total phenol content (TPC) in peels ranged from 1738.21 to 1757.76 mg GAE/100 g DW in dark red onion, 1306.58 to 1646.73 mg GAE/100 g DW in red onion, and 78.77 to 85.5 mg GAE/100 g DW in white onion varieties. The mean total anthocyanin content was maximum (28.23 mg/100 g DW) in dark red varieties (BDR) and minimum (0.11 mg/100 g DW) in white variety (BSW). Total antioxidant activity ranged from 4.71 to 79.80 μmol/g DW, 22.71 to 286.7 μmol/g DW, and 8.72 to 156.89 μmol/g DW estimated through FRAP, ABTS, and DPPH methods, respectively. In all three methods, it was maximum in dark red var. BDR and minimum in white var. BSU.

Onion Peel Extract Prevents Intestinal Inflammation via AMK-Activated Protein Kinase Activation in Caco-2/HT-29 Cells.

Obesogenic diets cause intestinal inflammation and dysfunction. Polyphenols have shown a positive impact on reducing inflammation in in vitro studies. However, their bioactivity may not be the same in the in vivo system due to structural alteration by the gastrointestinal digestive process. The purpose of this study was to investigate the anti-inflammatory effect of onion peel and its major bioactive compound, quercetin, in the intestine and further examine the impact of intestinal digestion on this effect. Onion peel extract (OPE) and quercetin (Q) were digested using gastrointestinal digestive enzymes in vitro and then treated into lipopolysaccharide (LPS)-stimulated Caco-2/HT-29 cells. Genes and proteins related to tight junction, inflammation, and epithelial integrity were measured. OPE and digested OPE (DOPE) had a higher protective effect on LPS-induced tight junction and inflammatory genes and paracellular permeability than Q and digested Q (DQ). DOPE was more effective than OPE, while digestion did not change the activity of Q. The anti-inflammatory effect of OPE and Q with or without digestion was achieved by inhibiting nuclear factor kappa B through AMP-activated protein kinase-activated silent mating-type information regulation 2 homolog 1. It was the first to find that a crude extract, after undergoing gastrointestinal digestion, demonstrated a notably superior anti-inflammatory effect in the cell study, suggesting the consumption of onion peels could potentially yield similar benefits in the human intestine. This discovery underscores the potential of onion peel polyphenols in combating intestinal inflammation, making them a compelling area of research for future therapeutic applications using food byproducts.

Storage Stability and Anthocyanin Degradation Kinetics of Alginate/Carboxymethyl Cellulose–based Emulsion Fortified with Red Onion Peel Extracts and its Application in the Preservation of Fresh Strawberries

Storage Stability and Anthocyanin Degradation Kinetics of Alginate/Carboxymethyl Cellulose–based Emulsion Fortified with Red Onion Peel Extracts and its Application in the Preservation of Fresh Strawberries

PSV-2 Rumen fluid metabolomics of dairy cows fed combinations of essential oil blend, onion peel extract and prebiotics using the RUSITEC system

Abstract Dairy products have a crucial role in the diets of over 6 billion people worldwide, providing essential nutrients such as energy, high-quality protein, and micronutrients. With dairy cows accounting for nearly 81% of global milk production, strategies to increase milk production sustainably are vital, especially with the U.S. being the second-largest producer. Essential oil blends (EOB), onion peel extract (OPE), and prebiotics such as mannan oligosaccharides (MOS) and galacto-oligosaccharides (GOS) offer promising avenues to enhance bovine milk production. These additives have the potential to modify rumen ecology and fermentation activity, while also mitigating greenhouse gas emissions in dairy cows. Therefore, this study investigated the effects of combining EOB, OPE, GOS, and/or MOS on specific rumen metabolites and metabolic pathways using the rumen simulation technique (RUSITEC) system. Rumen-cannulated non-lactating Holstein Friesian cows (n = 3) were used as rumen fluid donors. Total mixed ration (TMR) consisted of corn silage (60%), alfalfa hay (20%), and concentrate (20%). Using a completely randomized design, 16 fermentation vessels were divided into 4 groups with 4 replicates each over a 9-d period. The treatments included a control group (CON; TMR only), GEO (TMR+GOS+EOB+OPE), MEO (TMR+MOS+EOB+OPE), and OLEO (TMR+OLG+EOB+OPE). The EOB comprised of garlic, lemongrass, cumin, lavender, and nutmeg (4:2:2:1:1), while OLG contained GOS and MOS in equal proportions. EOB was added at 10 µL/g, and OPE, GOS, MOS, and OLG were included at 30 mg/g TMR. Rumen effluents were collected over 5 d for quantitative untargeted metabolome analysis. Analysis of rumen effluents using liquid chromatography-mass spectrometry and MetaboAnalyst 5.0 revealed 495 detected and identified metabolites. Volcano plot analysis showed no significant differences (P ≥ 0.05) in metabolite abundance between the CON and MEO, GEO, or OLEO treatments. Partial least squares-discriminant analysis (PLS-DA) also indicated no clear separation between the CON and treatment groups, suggesting no significant alteration in the metabolome. Compared with CON, the relative concentrations of dopamine 4-O-glucuronide, proline, and histamine were less while pyrocatechol was greater in MEO group. Isomer 1 of 2-hydroxyhepta-2,4-dienedioic acid, histamine, and dopamine 4-O-glucuronide were less while 2-aminomuconic acid and isomer 1 of hulupinic acid were greater in the GEO group. Histamine was less and hydroxypyridine was greater in the OLEO group. Phosphonate and phosphinate metabolism tended to be upregulated in OLEO. Meanwhile, metabolic pathways related to amino acids, vitamins, nitrogen metabolism, and primary bile acid biosynthesis remained unaltered by MEO, GEO and OLEO treatments. In summary, the study demonstrated that the inclusion of MEO, GEO, and OLEO had no adverse effects on rumen metabolites. Future research should focus on combinations of nutraceuticals that could positively impact nutrient metabolism and production performance of dairy cows.

Combination Effects of African Leaf Ethanol Extract (Vernonia amygdalina Del.) with Red Onion Peel (Allium cepa L.) as Antidiabetes in Streptozotocin-induced Mice

Type 2 diabetes arises when the body becomes resistant to insulin or when the pancreas fails to produce sufficient insulin. This study aimed to evaluate the antidiabetic effects of reducing blood glucose levels in white male mice through the administration of an ethanol extract of African leaves and onion peel, as well as to determine the duration of these effects. Streptozotocin was used to induce diabetes in the mice, and the experiment was conducted over a period of 21 days. The mice were divided into seven groups: Group 1 received a placebo (CMC Na 0.5%), Group 2 received glibenclamide (0.013 mg/20 g body weight), Group 3 received a single dose of African leaf extract (4.2 mg/20 g BW), Group 4 received a single dose of onion peel extract (4 mg/20 g BW), and Groups 5, 6, and 7 received combinations of African leaf and onion peel extracts at ratios of 1:1, 1:2, and 2:1, respectively. The results demonstrated that the combined administration of African leaf and onion peel extracts significantly reduced blood glucose levels, with decreases of 44.701%, 49.929%, and 51.996% in the 1:1, 1:2, and 2:1 group, respectively. The 1:1 combination was particularly effective, showing a reduction in blood glucose levels comparable to the positive control, which achieved a 45.957% decrease. The administration of the test preparations effectively reduced blood glucose levels over 21 days, with significant reductions observed on both the 14th and 21st days.

Active Food Packaging from Alginate-Based Film Containing Onion Peel Extract (Allium cepa)

Consumers wanting safe and eco-friendly food packaging have led to better active packaging materials. Alginate is a polysaccharide extracted from seaweed and has the potential to be considered a promising material for packaging applications; however, its application is limited due to poor mechanical properties and high water vapor (WVP). The mechanical and barrier properties can be altered by adding or blending with other materials, such as the incorporation of bioactive compounds from onion peel extract (Allium Cepa). This study was designed to extract onion peel and test its antioxidant and antimicrobial activities; alginate-based film incorporated different concentrations of onion peel extract (12.5%, 25%, and 50%) (w/v) and determined its antioxidant or antimicrobial activity and physicochemical properties. Results demonstrated that the onion peel extract and alginate-based films containing onion peel extract show antioxidant activity; however, no antimicrobial activity was detected. When the concentration of onion peel extract (Allium Cepa) in alginate-based film increased, it significantly improved the alginate-based film's mechanical properties, colour, solubility, and biodegradability. However, the water vapour permeability was reduced by increasing the onion peel extract. In conclusion, adding onion peel extract improved the antioxidant activity, colour, mechanical strength, solubility, and biodegradability characteristics of alginate-based films compared to control. Hence, this film has the potential to be used as active packaging.

Insights into bioactive constituents of onion (Allium cepa L.) waste: a comparative metabolomics study enhanced by chemometric tools

BackgroundOnion waste was reported to be a valuable source of bioactive constituents with potential health-promoting benefits. This sparked a surge of interest among scientists for its valorization. This study aims to investigate the chemical profiles of peel and root extracts of four onion cultivars (red, copper-yellow, golden yellow and white onions) and evaluate their erectogenic and anti-inflammatory potentials.MethodsUPLC-QqQ-MS/MS analysis and chemometric tools were utilized to determine the chemical profiles of onion peel and root extracts. The erectogenic potential of the extracts was evaluated using the PDE-5 inhibitory assay, while their anti-inflammatory activity was determined by identifying their downregulating effect on the gene expression of IL-6, IL-1β, IFN-γ, and TNF-α in LPS-stimulated WBCs.ResultsA total of 103 metabolites of diverse chemical classes were identified, with the most abundant being flavonoids. The organ’s influence on the chemical profiles of the samples outweighed the influence of the cultivar, as evidenced by the close clustering of samples from the same organ compared to the distinct separation of root and peel samples from the same cultivar. Furthermore, the tested extracts demonstrated promising PDE-5 and anti-inflammatory potentials and effectively suppressed the upregulation of pro-inflammatory markers in LPS-stimulated WBCs. The anti-inflammatory activities exerted by peel samples surpassed those of root samples, highlighting the importance of selecting the appropriate organ to maximize activity. The main metabolites correlated with PDE-5 inhibition were cyanidin 3-O-(malonyl-acetyl)-glucoside and quercetin dimer hexoside, while those correlated with IL-1β inhibition were γ-glutamyl-methionine sulfoxide, γ-glutamyl glutamine, sativanone, and stearic acid. Taxifolin, 3’-hydroxymelanettin, and oleic acid were highly correlated with IL-6 downregulation, while quercetin 4’-O-glucoside, isorhamnetin 4’-O-glucoside, and p-coumaroyl glycolic acid showed the highest correlation to IFN-γ and TNF-α inhibition.ConclusionThis study provides a fresh perspective on onion waste as a valuable source of bioactive constituents that could serve as the cornerstone for developing new, effective anti-PDE-5 and anti-inflammatory drug candidates.

Onion Peel Extract/Copper Oxide Nanoparticles as Corrosion Inhibitors for Carbon Steel in Hydrochloric Acid: Extraction, Characterization, Electrochemical Study, and Theoretical Explorations

The effectiveness of onion peel extract (OPE) as a corrosion inhibitor for carbon steel in a 1 M hydrochloric acid solution was investigated using weight loss (WL) techniques, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and surface morphological examination. Additionally, this process was characterized by Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and transmission electron microscopy (TEM). According to weight loss measurements, the protective efficiency of OPE increases with rising OPE concentration and decreases with increasing temperature of the corrosive solution. Polarization curves indicate that OPE acts as a mixed-type inhibitor in hydrochloric acid. The adsorption mechanism, supported by EIS results, shows that charge-transfer resistance increases and double-layer capacitance decreases with higher inhibitor concentration. The adherence of OPE to carbon steel follows the Langmuir isotherm, indicating a physical adsorption process, and the spontaneous adsorption of the inhibitor molecules is evidenced by the negative values of Gibb’s free energy of adsorption. The synergistic effect of copper oxide nanoparticles (CuO–NPs) in combination with OPE on the corrosion inhibition of carbon steel was also evaluated. The results demonstrated that the inhibition efficiency of OPE is enhanced in the presence of CuO–NPs due to synergistic interactions between OPE extract molecules and CuO–NPs. The electron-donating capacity of the chemical components in OPE was confirmed through theoretical studies employing quantum chemistry methods.

Poly-vinyl-pyrrolidone capped luminescent zinc oxide nanocomposites as excellent tools for germicidal and photo-catalytic performances.

Alternate antibiotics developed through the involvement of nanomaterials are gaining interest due to their economical and lower toxicity concerns. A newly developed biopolymer-based polyvinylpyrrolidone/zinc oxide (PVP/ZnO) nanocomposite (NCs) was efficiently synthesized by an environment-friendly approach, utilizing onion and garlic peel extract as a bio-surfactant, zinc acetate as the source, PVP as the stabilizing agent, and sodium hydroxide as the precipitant. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) investigations verified the crystalline properties of ZnO, PVP, and PVP/ZnO-based NCs. The structure of the biopolymer-linked ZnO particles interpolated inside the PVP array was seen to have a layered and flaky structure, as validated by field emission scanning electron microscopy (FE-SEM) analysis, which revealed its occurrence in the nanometer range. The XRD examination verified that the surface topographical image of PVP/ZnO NCs had an average thickness of 21 nm. The PVP/ZnO nanocrystals demonstrated exceptional photocatalytic efficacy, with a breakdown rate of 88% and almost 92% for the methylene blue dye. Therefore, the PVP/ZnO matrix exhibits superior antibacterial activity compared to other extracts, resulting in greater microbial suppression. The results above indicate that the ZnO-intercalated PVP array has a stronger reinforcing effect than other components. Hence, PVP/ZnO nanocrystals exhibit enormous potential as a favorable substance for environmental and biomedical intentions.

Enhancing the stability of DSSC by Co-activation of microwave synthesized TiO2 with biomass derived carbon dots

Dye-sensitized solar cells (DSSCs) that utilize natural dyes have garnered interest due to their low cost, eco-friendly manufacturing process, and competitive photovoltaic performance. However, their efficiency and stability issues have hindered their widespread implementation. To enhance their performance, this paper proposes a novel approach of modifying the photoanode with carbon dots (CDs) to align the band gap for easier carrier collection. The material properties were thoroughly characterized by examining their structural, morphological, optical, and electrical properties. In this study, titanium dioxide (TiO2) was synthesized using the microwave-assisted solvothermal method, while nitrogen-doped CDs derived from Citrus medica fruit juice were prepared using a simple hydrothermal treatment. Three sets of Natural Dye Sensitized Solar Cells (NDSSC) devices were created using co-activated photoanode (CD/TiO2) and unmodified photoanode (TiO2) with Platisol T/sp coated ITO serving as the counter electrode. Hibiscus (Hibiscus rosa-sinensis) and Onion (Allium cepa) peel extracts were utilized as sensitizers and Iodolyte HI-30 as the electrolyte. The most efficient device attained an efficiency of 3.5 % with Voc = 0.81 V and Jsc = 6.57 mA/cm2. This marks the highest efficiency reported using Hibiscus as a sensitizer with the current configuration, accompanied by prolonged device stability. This study showcases the potential of Citrus medica-derived nitrogen-doped CDs in achieving durable device stability.

An enhanced multifunctional chitosan-based active packaging film reinforced with cinnamon essential oil encapsulating onion peel anthocyanins

The fabrication of bio-hybrid composites utilizing polymers, nanomaterials, essential oils, and other substances is gaining popularity due to its multi-functionality and application across various fields. Many industries today effectively employ innovative composite and multilayer materials by considering their benefits in several areas. In particular, the food industry uses innovative, multi-functional packaging materials based on biodegradability to accomplish multiple tasks. Many researchers have recently shown interest in an innovative and intelligent food packaging film with indicators for real-time food safety and protection. It is preferable to use anthocyanins, as an indicator in the active packaging film to track the freshness of food by observing color changes in the packaged film upon a shift in pH. In the current investigation, ethanol was used as a solvent to obtain anthocyanin-rich onion peel extracts (AROPE), using conventional and ultrasound-assisted extraction techniques, which were then used as an indicator in the packaging films. To develop antioxidant and pH-sensing films, anthocyanin-rich onion peel extract was blended into the chitosan and cinnamon essential oil matrix. Films displayed significant color variations in acidic and alkaline environments over short periods making them easy to perceive with the naked eye. For real-world applications, the fabricated films mechanical, structural, and physical characteristics were further explored. Because of their sensory qualities, colors, and antimicrobial benefits, these novel chitosan-based films could be ideal for food packaging to enhance food security.

Antimicrobial Properties of Newly Developed Silver-Enriched Red Onion-Polymer Composites.

Simple low-cost, nontoxic, environmentally friendly plant-extract-based polymer films play an important role in their application in medicine, the food industry, and agriculture. The addition of silver nanoparticles to the composition of these films enhances their antimicrobial capabilities and makes them suitable for the treatment and prevention of infections. In this study, polymer-based gels and films (AgRonPVA) containing silver nanoparticles (AgNPs) were produced at room temperature from fresh red onion peel extract ("Ron"), silver nitrate, and polyvinyl alcohol (PVA). Silver nanoparticles were synthesized directly in a polymer matrix, which was irradiated by UV light. The presence of nanoparticles was approved by analyzing characteristic local surface plasmon resonance peaks occurring in UV-Vis absorbance spectra of irradiated experimental samples. The proof of evidence was supported by the results of XRD and EDX measurements. The diffusion-based method was applied to investigate the antimicrobial activity of several types of microbes located in the environment of the produced samples. Bacteria Staphylococcus aureus ATCC 29213, Acinetobacter baumannii ATCC BAA 747, and Pseudomonas aeruginosa ATCC 15442; yeasts Candida parapsilosis CBS 8836 and Candida albicans ATCC 90028; and microscopic fungi assays Aspergillus flavus BTL G-33 and Aspergillus fumigatus BTL G-38 were used in this investigation. The greatest effect was observed on Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa bacteria, defining these films as potential candidates for antimicrobial applications. The antimicrobial features of the films were less effective against fungi and the weakest against yeasts.

Effects of the Ethanolic Extract of Onion Peel on the Physicochemical Properties of Wheat Starch

AbstractThe objective of this study is to examine the interactions between wheat starch (WS) and ethanol extract of onion peel (EEOP) at varying concentrations (1.0%, 2.5%, 5.0%, and 10.0%) during the process of gelatinization, and to assess the impact of these interactions on the physicochemical and retrogradation characteristics of wheat starch. In contrast to the control group, the incorporation of EEOP results in a reduction in retrogradation, an increase in solubility, and an increase in the swelling degree of wheat starch. Furthermore, the addition of the EEOP effectively hinders the retrogradation process of wheat starch. The incorporation of EEOP has the potential to decrease the enthalpy associated with starch retrogradation. Accordingly, the addition of 10% EEOP results in a decrease of 43.6% in the enthalpy of starch retrogradation in wheat starch after a storage period of 15 days, as compared to the control group. In addition, the incorporation of an enzyme known as EEOP has the potential to reduce the occurrence of crystallization in the process of starch retrogradation. Hence, the incorporation of EEOP may impede the regression of WS.

Onion Peel as a Potential Source of Antioxidants and Antimicrobial Agents

Dry outer onion leaves resulting from the industrial processing of onions are currently discarded as agricultural waste, although some studies have demonstrated that onion peel has beneficial biological effects. Considering the traditional applications of onion peel, the present study evaluated comparatively the chemical and biological characteristics of four types of onion peel extracts, utilizing methanol, ethanol, acetone, or ethyl acetate as the extracting solvent. The extracts were analyzed for their chemical composition, antioxidant potential, and antimicrobial activity. The chemical analysis by UHPLC-DAD-ESI/MS identified 23 compounds in the extracts, belonging to phenolic acids and flavonoids. Quercetin was the main compound in all extracts, ranging in concentrations from 14.91 mg/g DW in the ethanol extract to 48.53 mg/g DW in the methanol extract. The highest contents of total phenols and flavonoids were found in the acetone extract, and the methanol extract demonstrated the highest antioxidant activity in DPPH and ABTS assays. The antimicrobial potential of the extracts was screened using a microdilution method against a spectrum of gastrointestinal microorganisms. The results revealed that all four extracts have significant antimicrobial potential against the tested microorganisms, of which the ethanol extract demonstrated the highest antimicrobial potency.

Green Synthesis of Silver/Silver Chloride Nanoparticles using Shallot Peel Extract as Reducing Agent

Precious metal nanoparticles, especially silver, can be an alternative antibacterial agent that is more promising than antibiotics, which tends to induce resistance over time. Unfortunately, most Silver nanoparticle (AgNP) manufacturing methods involve hazardous substances, extreme conditions, high energy, and complicated separations. Reduction of AgNO3 solution with plant extracts can serve as a ‘green’ synthesis pathway, especially if using food processing waste or other biological materials. Reducing substances that are commonly found in plant extracts, such as flavonoids, are widely contained in shallots (Allium cepa L. var. aggregatum) which are commonly used as food ingredients in Indonesia, but the processing waste is still not widely used. This paper describes the synthesis of silver nanoparticles (AgNP) with the AgNO3 solution reduction method, using onion peel waste extract as a reducing agent. Experiments were carried out with variations in the ratio of AgNO3 solution to onion peel extract. The resulting AgNPs were characterized by TEM and UV-vis.

Phytosynthesis via wasted onion peel extract of samarium oxide/silver core/shell nanoparticles for excellent inhibition of microbes

The aqueous onion peel extract (OPE) was used to synthesize silver nanoparticles (Ag-onion), samarium oxide nanoparticles (Sm2O3-onion), and silver/samarium oxide core/shell nanoparticles (Ag@Sm2O3-onion). The produced nanoparticles were characterized by thermal gravimetric analysis (TGA), infrared spectra (FT-IR), absorption spectra (UV–Vis), energy band gap, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), zeta potential, and transmission electron microscopy (TEM). OPE and NPs were tested for the disinfection of some water microbes. XRD analysis exhibited an amorphous structure of samarium oxide in both Sm2O3-onion and Ag@ Sm2O3-onion. The isolated bacteria from the water sample were Bacillus subtilis (OQ073500) and Escherichia coli (MW534699), while the isolated fungi were Alternaria brassicae (MZ266540), Aspergillus flavus (MT550030), Aspergillus penicillioides (MW957971), Pythium ultimum (MW830915), Verticillium dahlia (MW830379), Fusarium acuminatum (MZ266538), Candida albicans (MW534712), and Candida parapsilosis (MW960416). High levels of antimicrobial activity were seen in both the nanoparticles and the aqueous onion peel extract. Based on experimental results, Ag@Sm2O3 demonstrated the highest activity as an effective disinfectant, indicating the effectiveness of the modification process.

A sustainable synthesis, characterization of modified waste onion peels and its exploration in various applications

The modification of waste to a bio-based material that is economical, environmentally sustainable, and extremely effective is crucial for organic conversions. For bio waste, that doesn’t decompose easily and have bad impact on environment such as onion peels, a suitable method is introduced which focuses on utilizing onion peels, a commonly discarded agricultural waste, as a valuable resource for antibacterial studies and bio sensing of heavy metals. A comparative study to analyse these properties were done using onion peel extract and saponified onion peels. The saponified material was obtained by treating onion peels (Allium cepa) with sodium hydroxide in the presence of calcium carbonate. The popularity of saponification reaction and saponified material is rising because of their special qualities and uses as disinfectants, surfactants, antifungal agents, in drugs for target based delivery etc. The saponified onion peels was analyzed by FTIR (Fourier transform infrared spectroscopy), and XRD (X-ray diffraction), EDX (energy-dispersive X-ray), SEM (scanning electron microscopy). Furthermore, against Bacillus subtilis (Gram positive), antibacterial activity of onion extract and saponified onion peels were studied. In comparative study onion peel extract shows better inhibition zone then saponified onion peels. Bio sensing of heavy metals were done by using these materials, onion peel extract shows visual colour change with Nickel chloride (NiCl2), Cobalt chloride (CoCl2), Potassium bromide (KBr), Manganese sulphate (MnSO4), Mercury chloride (HgCl2) and Copper sulphate (CuSO4) metal salts.

Development of Antibacterial Cotton Fabric by Application of Fruit and Vegetable Peel Extracts - A Sustainable Approach

The objective of this study is to assess the effect of Solanum incanum fruit (SIFE) and red onion peel (ROPE) extracts treatments on cotton fabric properties. The two factor factorial design was used, the first factor is concentration of the methanolic extract with two levels (3 g/l and 5 g/l) and the second is combination of extracts (25:75 SIFE: ROPE; 50:50 SIFE: ROPE; 75:25 SIFE: ROPE, 100% SIFE, 100% ROPE). Each extract was applied separately and in combination of different proportions on cotton fabric by the pad-dry-cure method using citric acid as a cross-linking agent. After treatment, the physical properties antimicrobial, wash durability and structual properties were determined. Air permeability, water absorbency and tensile strength were decreased for the treated fiber compared with control. Among all treatments, the cotton fabric treated with 50:50 combination was found best in bacterial reduction. This study concluded that, the natural source can sucessfully replace with synthetic chemicals.

Onion peel extract as milk freshness indicator in biopolymer-based intelligent packaging films

Intelligent food packaging is used to monitor quality / freshness of packaged food product, and to communicate them to consumers. Natural color-based pH indicators can be effective agents in biopolymer-based intelligent packaging systems. In this study, gelatin and sodium alginate-based sustainable intelligent packaging films incorporated with onion peel extract (OPE) as the pH indicator were fabricated for monitoring and indicating milk freshness. Effects of incorporation of OPE on moisture content, solubility, swelling, transparency, antioxidant activity, and total phenolic contents of the fabricated films were also evaluated. The developed films were characterized using Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), and their color changes due to pH sensitivity were measured. The fabricated intelligent films / labels were tested against milk at different pH of 6.5, 6, 5.5, 5, 4.5, 4, and 3.5, and the discernible color changes were measured. The developed intelligent films / labels showed significant change in their color with change in pH of the milk samples. Thus, the films can be used as sustainable alternative, as freshness indicator for packaged milk.

The Chemistry Behind Biological Properties of Agro-industrial Portuguese By-Products

As the global population grows, food production and processing generate significant by-products that cause environmental issues. These by-products contain bioactive compounds, including phenolic compounds, which have beneficial biological properties. Extracting these compounds and incorporating them into various products, can promote circular economy. This study examined the correlation between the chemical composition and biological properties of phenolic-rich extracts from chestnut shells, grape seeds, onion peels, and passion fruit peels. Using HPLC–DAD, the primary compounds were identified and quantified. The study analysed their antioxidant, and antibacterial properties, sun protection factor, and α-amylase inhibitory capacity. Catechin was found in all four extracts, with the grapeseed extract having higher levels. Chestnut shell extract revealed the best antioxidant properties, with a total phenolic content of 497.5 mgGAE/g. On the other hand, onion peel extract exhibited the best antibacterial capacity, as well as the highest sun protection factor value (4.8). Concerning the ability to inhibit the α-amylase enzyme, all the extracts displayed the ability to inhibit more than 70% of this enzyme. Overall, the presented extracts had varying phenolic compositions and biological properties. It is crucial to evaluate the chemical composition of extracts to comprehend their biochemical properties and define their potential applications.Graphical