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A continuous population and industrialization growth have enhanced the production of chemical compounds as well as their structural chemical diversification. Unfortunately, they have become an increasing burden for the environmental sustainability and biodiversity. The need for producing and using environmentally friendly products become increasingly evident in the current context of environmental concerns. It is crucial to develop new products and technologies that reduce their overall harmful environmental impact and promote its sustainability. In this study, the citrus peels waste was transformed into a potential antibacterial and antifungal extract by hydrodistillation. The efficacy of orange peels hydro distillation process in obtaining plant extracts was improved by a pre-enzyme-assisted extraction step. Enzymes such as cellulase and pectinase improved the breakdown of cellulose and pectin structures, which led to an increased extraction yield of bioactive compounds and antimicrobial activity.

The citrus processing industry is responsible for the generation of large volumes of waste side streams, represented principally by fruit peels. These tissues are exceptionally rich in polyphenolic bioactive phytochemicals, and there has been a great industrial interest for their valorization. The examination presented herein targeted at developing a fast and straight-forward aqueous extraction process, based on ultrasonication, for the efficacious recovery of polyphenolic compounds from waste orange peels. After an initial single-factor examination, the response surface optimization showed that a maximum total polyphenol yield of 12.81 mg chlorogenic acid equivalents (GAE) per g−1 dry mass could be achieved by setting sonicator amplitude at 80%, for 15 min, using a duty cycle of 2/2 (2 s on/2 s off). Comparison of this methodology with a stirred-tank extraction demonstrated that the ultrasonication technique was equally effective, requiring ambient temperature and considerably shorter resident time. The combination of both techniques using the ultrasonication process as a pretreatment step did not boost extraction yield, and the extracts produced had similar polyphenolic composition and antioxidant activity. However, a slight enhancement of the recovery of individual constituents was noted. It is proposed that efficient extraction of polyphenolic substances from waste orange peels may be accomplished using the present methodology, which is a low-cost (ambient temperature, short time) and sustainable (water as solvent) process. [ABSTRACT FROM AUTHOR]

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The citrus processing industry is responsible for the generation of large volumes of waste side streams, represented principally by fruit peels. These tissues are exceptionally rich in polyphenolic bioactive phytochemicals, and there has been a great industrial interest for their valorization. The examination presented herein targeted at developing a fast and straight-forward aqueous extraction process, based on ultrasonication, for the efficacious recovery of polyphenolic compounds from waste orange peels. After an initial single-factor examination, the response surface optimization showed that a maximum total polyphenol yield of 12.81 mg chlorogenic acid equivalents (GAE) per g−1 dry mass could be achieved by setting sonicator amplitude at 80%, for 15 min, using a duty cycle of 2/2 (2 s on/2 s off). Comparison of this methodology with a stirred-tank extraction demonstrated that the ultrasonication technique was equally effective, requiring ambient temperature and considerably shorter resident time. The combination of both techniques using the ultrasonication process as a pretreatment step did not boost extraction yield, and the extracts produced had similar polyphenolic composition and antioxidant activity. However, a slight enhancement of the recovery of individual constituents was noted. It is proposed that efficient extraction of polyphenolic substances from waste orange peels may be accomplished using the present methodology, which is a low-cost (ambient temperature, short time) and sustainable (water as solvent) process.

Citrus peels contain abundant polyphenols, particularly flavonoids, and have been shown to exert lipid accumulation decreasing ability. In this study, Citrus depressa peel applied to oven drying and extracted with ethanol extract as CDEE to analyze its flavonoids compositions and investigated its effects on a high-fat diet (HFD)-induced obese mice model. CDEE contained several flavonoids such as hesperidin, sinesentin, nobiletin, tangeretin, 5-demethylnobiletin, and 5-demethyltangeretin. The mice fed an HFD, and administration of 2% CDEE to could decrease weight gain, abdominal fat weight, inguinal fat weight, and the adipocyte size, and CDEE also reduced serum total cholesterol (TCHO), triacylglycerol (TG) compared with mice fed only on HFD. CDEE hindered lipid accumulation through a decreased fatty acid synthase (FAS) protein expression via upregulation of the protein expression of AMP-activated protein kinase α (AMPKα). Moreover, CDEE modulated gut microbiota that altered by HFD through an increased abundance of Lactobacillus reuteri compared with the HFD group. The results demonstrated that CDEE helps decrease lipid accumulation through the AMPK pathway, which also indicates a prebiotic-like effect on gut microbiota. [ABSTRACT FROM AUTHOR]

Citrus peels are an important by-product of citrus processing industries, but a large part is considered waste. There has been increased attention in the last five years on these industrial by-products, especially those containing residual essential oils (EOs). Lemon, orange, and mandarin peels from Egypt were subjected to hydro-distillation to obtain EOs, which were analyzed via mass spectrometry (GC/MS) and by building Global Natural Products Social Molecular Networking (GNPS-MN) for the purpose of visually exploring the volatile components of citrus species. The constructed MN revealed that D-Limonene, α-pinene, and β-pinene are the dominant volatile constituents in the three Egyptian citrus species. The EOs from three citrus peels exhibited promising activities as antioxidants using two tested methods: 1,1-diphenyl-2-picryl-hydrazil (DPPH) and nitric oxide (NO) compared with vitamin C. Lemon EO proved excellent antimicrobial activity against Gram-positive and negative bacteria. Additionally, the three citrus EOs showed good activities against the yeast Candida albicans. Regarding the anti-inflammatory assay, the three citrus EOs showed promising activities as COX-1 and COX-2 inhibitors. This study concludes that EOs extracted from citrus peel waste can be valorized as an innovative strategy for food preservation or may be incorporated in cosmetics and pharmaceutical formulations in alignment with circular economy principles. [ABSTRACT FROM AUTHOR]

Breakfast cereals (BFCs) are a popular choice for breakfast and the BFC market is growing at an annual rate of 4.1 % and stands as a 70 billion dollar enterprise today. However, there are a number of questions raised about the medicinal properties of BFCs as they are processed foods lot of added refined sugars and reduced fibres especially when made from processed grains. Therefore, improving the medicinal values of BFCs will include minimizing the refined sugar content, increasing the fibre content and fortifying with natural bioactive compounds which possess medicinal properties. Citrus peels are rich in fibre and bioactive compounds, even though they are considered a waste in many countries. Incorporating citrus peels into BFCs without adversely affecting the sensory properties will enhance the medicinal properties of BFCs as the peels have a number of already established medicinal properties. Citrus peel-enriched BFCs could be a tool in Functional Nutrition as they will not only supply needed nutrients to start the day, but they will also be able to prevent and manage degenerative conditions through their ability to modulate other factors connected with diseases such as inflammation regulation, mood disorders and weight control.

High volume of postharvest materials including peels from citrus fruits is periodically generated, which contributes to environmental pollution. Investigating the chemical composition cum antioxidant property of these ‘wastes’ would be instructive in achieving value addition in the food and pharmaceutical value chain. On this premise, this study carried out phytochemical screening and antioxidant activity of three (3) commonly cultivated citrus varieties namely Citrus sinensis ‘valencia’, Citrus sinensis ‘washinton’ and Citrus sinensis ‘thompson navel’. The peels were extracted using ethanol and hexane in a Soxhlet extractor and thereafter subjected to phytochemical and Gas Chromatography/Mass Spectrometry (GC/MS) analyses, ferric ion reducing antioxidant power (FRAP), hydrogen peroxide scavenging and cupric ion reducing antioxidant capacity (CUPRAC) assays to evaluate their antioxidant potentials. Results show that Citrus sinensis peel extracts contain alkaloids, flavonoids, phenols, phytosterols, diterpenes, tannins and glycosides. GC/MS analysis identified about 48 compounds in each extract; with the predominant bioactive compounds being limonene (16.5%), ascorbic acid (17.7%), stearic acid (26.3%), linalool (4.7%), linoleic acid (16.18%), palmitic acid (15.23%), pentadecyclic acid (1.1%). Ethanol and hexane extracts of Valencia exhibited higher FRAP (9.09 ± 0.13) and CUPRAC (2.04 ± 0.06) values while the ethanol extract of Ibadan sweet demonstrated greater hydrogen peroxide scavenging activity (1.39 ± 0.00). Citrus peels are rich in bioactive compounds with excellent antioxidant activity and may serve as potential sources of natural antioxidants for food products or pharmaceutical formulations.

Citrus peels are an important by-product of citrus processing industries, but a large part is considered waste. There has been increased attention in the last five years on these industrial by-products, especially those containing residual essential oils (EOs). Lemon, orange, and mandarin peels from Egypt were subjected to hydro-distillation to obtain EOs, which were analyzed via mass spectrometry (GC/MS) and by building Global Natural Products Social Molecular Networking (GNPS-MN) for the purpose of visually exploring the volatile components of citrus species. The constructed MN revealed that D-Limonene, α-pinene, and β-pinene are the dominant volatile constituents in the three Egyptian citrus species. The EOs from three citrus peels exhibited promising activities as antioxidants using two tested methods: 1,1-diphenyl-2-picryl-hydrazil (DPPH) and nitric oxide (NO) compared with vitamin C. Lemon EO proved excellent antimicrobial activity against Gram-positive and negative bacteria. Additionally, the three citrus EOs showed good activities against the yeast Candida albicans. Regarding the anti-inflammatory assay, the three citrus EOs showed promising activities as COX-1 and COX-2 inhibitors. This study concludes that EOs extracted from citrus peel waste can be valorized as an innovative strategy for food preservation or may be incorporated in cosmetics and pharmaceutical formulations in alignment with circular economy principles.

Citrus fruits have been consumed by world's population for several centuries. Since it's an edible source possesses various uses in treating many diseases. Among various diseases urolithiasis is one of the major issues globally demands in painless surgical treatment. Calcium Oxalate (CaOx) is found to be the most prevailing constituent of renal calculus in humans which tends to be the categories of the urolithiasis. Citric acid is commonly used in treating to dissolve them in medications. Citrate compound has the ability to bind with calcium stones to relieve oxalates in urine. The objective of the present study is to assess the efficacy of citrate compounds from waste citrate peels describing the inhibition of calcium oxalate (CaOx) crystals. Multistep extraction procedures were performed for the selected citrus peels of Citrus limon, Citrus limetta and Citrus sinensis using different solvents (hexane, aqueous and ethanol) and were tested for its inhibitory actions with different parameters against the synthesized CaOx crystals. The synthetic CaOx crystals were characterized by Microscopy, FTIR, SEM, XRD, and TGA. The structural change in the crystal was observed for inhibition at various stages like nucleation, growth and aggregation when treated with the ethanol extracts of citrus peels. Thus the present investigation concludes that the ethanol extracts of C. sinensis peels highly inhibits at a concentration of 1000 (µg/mL) in 60 min when compared to other solvents. This research would give additional information in preparation of drugs against CaOx urolithiasis in future pharmaceutical development processes. [ABSTRACT FROM AUTHOR]

Obtaining polyphenols from horticultural waste is an emerging trend that enables the valorization of resources and the recovery of value-added compounds. However, a pivotal point in the exploitation of these natural extracts is the assessment of their chemical stability. Hence, this study evaluates the effect of temperature storage (20 and −20 °C) and drying methods on the phenolic composition and antioxidant activity of clementine and lemon peel extracts, applying HPLC-DAD-MS, spectrophotometric methods, and chemometric tools. Vacuum-drying treatment at 60 °C proved to be rather suitable for retaining the highest antioxidant activity and the hesperidin, ferulic, and coumaric contents in clementine peel extracts. Lemon extracts showed an increase in phenolic acids after oven-drying at 40 °C, while hesperidin and rutin were sustained better at 60 °C. Hydroethanolic extracts stored for 90 days preserved antioxidant activity and showed an increase in the total phenolic and flavonoid contents in lemon peels, unlike in clementine peels. Additionally, more than 50% of the initial concentration was maintained up to 51 days, highlighting a half-life time of 71 days for hesperidin in lemon peels. Temperature was not significant in the preservation of the polyphenols evaluated, except for in rutin and gallic acid, thus, the extracts could be kept at 20 °C. [ABSTRACT FROM AUTHOR]

The peels extracted from various citrus species are major source of phenols, flavonoids and anti-microbial agents. The purpose of this study was a detailed investigation of the phytochemical and pharmacological character of the ethanolic (80%), methanolic and acetone extracts of the peel of local variants of orange (lemon, grape fruit, mousami, fruiter, and shikri malta). The extracts were studied to find out the total phenolic contents (TPC), and total flavonoids (TF) present. The antioxidant activities were assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging effect, and the reducing power was determined through free radical scavenging activity (FRAP) assays. The sensitivity of four bacterial strains to peels extracts was examined by applying the diffusion disc on agar medium method. It was found that ethanol was the best extracting agent for TPC and TF in fruit peels under study. The highest TPC (21.33 ± 0.06 mg GAE/g) was quantified in orange peels, whereas fruiter contained the lowest TPC (20.40 ± 0.03 mg GAE/g) in ethanolic extract. The highest amount of TF (2.02 ± 0.08 mg QE/g) was quantified in lemon peels, whereas shikri malta contained lowest quantity of TF (1.04 ± 0.02 mg QE/g). The highest free radical scavenging activity (93.1%) of DPPH was exhibited by lemon peels, whereas the least activity (78.6%) was shown by mousami peels. Ethanolic extract of orange peels demonstrated more reducing power while showing an absorption of 1.98, followed by methanolic (1.11) and acetone (0.81) extracts. The inhibition effect of methanolic extract of lemon peels (inhibition zone = 18 mm) against B. subtilis was considerable and comparable to that of ciprofloxacin. Gas chromatography/mass spectrometry (GC/MS) was used to detect the compounds in ethanolic extract and up to 14 compounds were detected. These compounds were also assessed for their docking scores. Plausible binding modes with polyphenol oxidase and four best compounds were selected for molecular dynamics (MD) simulation to analyze their structural stability with receptor.

The bioactive components and bioactivities of citrus peel can be enhanced with microbial fermentation. Accordingly, this study investigated the ability of Aspergillus niger CGMCC3.6189 to accumulate flavonoids in Citrus reticulata peel powder (CRPP) by solid-state fermentation (SSF). Under the optimal SSF conditions including 80% moisture, 30 °C, pH 4.0, 4 × 107 spores/g d.w. CRPP, and 192 h, the total phenolic content (TPC), total flavonoid content (TFC), and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activities of fermented CRPP significantly increased by 70.0, 26.8, 64.9, and 71.6%, respectively. HPLC analysis showed that after fermentation, the contents of hesperidin, nobiletin, and tangeretin were significantly increased from 19.36, 6.31, and 2.91 mg/g to 28.23, 7.78, and 3.49 mg/g, respectively, while the contents of ferulic acid and narirutin were decreased under the optimal fermentation conditions. Fermentation time is one of the most important factors that affect the accumulation of flavonoids and antioxidant activity; however, extended fermentation time increased the darkness of CRPP color. Therefore, our study provides a feasible and effective SSF method to increase the bioactive components and the antioxidant activity of CRPP that may be used in food, nutraceutical, and medicinal industries. [ABSTRACT FROM AUTHOR]

In this study, 126 Cobb 500 commercial broiler chicks were fed a control basal (C) diet (corn-soy basal diet on an ad libitum basis) alone or with two different citrus peel. A completely randomized design with 42 chickens was used to investigate the effect of 2% orange peel (OP) or 2% grapefruit peel (GP) on broiler performances and thigh meat quality. The treatment containing 2% OP had a significant (P

This study focused on the use of citrus bio-waste and obtention of silica-based materials through the sol-gel technique for promoting a greener and more sustainable catalysis. The sol-gel method is a versatile synthesis route characterized by the low temperatures the materials are synthesized in, which allows the incorporation of organic components. This method is carried out by acid or alkali hydrolysis combined with bio-waste, such as orange and lemon peels, generated as co-products in the food processing industry. The main objective was to obtain silica-based materials from the precursor TEOS with different catalysts—acetic, citric and hydro-chloric acids and ammonium hydroxide—adding different percentages of lemon and orange peels in order to find the influence of bio-waste on acids/alkali precursor hydrolysis. This was to partially replace these catalysts for orange or lemon peels. The solids obtained were characterized with different techniques, such as SEM, FT₋IR, potentiometric titration and XRD. SEM images were compared with pure silica obtained to contrast the morphology of the acidic and alkali hydrolysis. However, until now, few attempts have been made to highlight the renewability of reagents used in the synthesis or to incorporate bio-based catalytic processes on larger scales.

Citrus peel, a fruit-processing waste, is a substantial source of naturally occurring health-promoting compounds, including polyphenols, and has great potential as a dietary supplement for enhancing the functional properties of food. The present work aimed to investigate the effects of sour orange (SO), sweet orange (SWO), and lemon (LO) peels on the typical physiochemical, antioxidant, antibacterial, and probiotic properties of synbiotic yoghurt fermented by acidophilus-bifidus-thermophilus (ABT)-type cultures during cold storage (0–28 days). High-performance liquid chromatography-diode array detection (HPLC-DAD) analysis showed that the total phenolic content in the SO peel were more than 2-fold higher than that in the SWO and LO peel. The predominant phenolic compounds were myricetin (2.10 mg/g dry weight) and o-coumaric acid (1.13 mg/g) in SO peel, benzoic acid (0.81 mg/g) and naringin (0.72 mg/g) in SWO peel, and benzoic acid (0.76 mg/g) and quercetin (0.36 mg/g) in LO peel. Only 0.5% (w/w) of citrus peel addition did not reduce the overall acceptance of ABT synbiotic yoghurt but led to increased acidity and decreased moisture during cold storage (14 and 28 days). Additionally, compared to control samples without citrus peel addition, supplementation with citrus peels improved the antioxidant property of the ABT synbiotic yoghurt. ABT milks with SO and SWO peel addition had significantly stronger DPPH radical scavenging activities than that with LO peel addition (p < 0.05). Antibacterial analysis of ABT synbiotic yoghurt with citrus peel addition showed that the diameters of inhibition zones against S. aureus, B. subtilis, and E. coli increased by 0.6–1.9 mm relative to the control groups, suggesting the enhancement of antibacterial activities by citrus peels. The viabilities of probiotic starter cultures (L. acidophilus, S. thermophilus, and Bifidobacterial sp.) were also enhanced by the incorporation of citrus peels in synbiotic yoghurt during cold storage. Hence, our results suggest that citrus peels, especially SO and SWO peels, could be recommended as a promising multifunctional additive for the development of probiotic and synbiotic yoghurt with enhanced antioxidant and antibacterial properties, as well as probiotic viability. [ABSTRACT FROM AUTHOR]

Gastric ulcer and hepatotoxicity due to irrational drug overuse are two of the most serious conditions associated with inflammation and oxidative stress that affect the digestive system. This study aimed to experimentally evaluate the hepatoprotective/gastroprotective effects of aqueous and butanol citrus peel extracts and hesperidin in rat models of ulcer and hepatotoxicity. Acute toxicity study was performed for determining the safe dose of citrus extracts to analyze efficacy. In the experiments on hepatoprotective and gastroprotective effects, rats were classified into nine groups in each experiment: (1) negative control, (2) positive control hepatotoxic model with paracetamol (640 mg/kg)/gastric ulcer model:ethanol 70% (1 ml), (3)reference hepatoprotective:silymarin (25 mg/kg)/gastroprotective:ranitidine (50 mg/kg), and (4–9) groups treated for 2 weeks before induction of each disease with either citrus aqueous or butanol extracts or hesperidin (125–250 mg/kg). Drugs, ethanol, or tested compounds were administered orally. The levels of biochemical parameters, such as AST, ALT, NO, MDA, CRP, and ILβ6, were significantly reduced, but CAT level was increased. Postmortem examination of liver and stomach tissues of treated animals revealed marked improvement compared with positive control animals. Hesperidin exerted the best hepatoprotective, antioxidant, anti-inflammatory, and gastroprotective effects, followed by butanol and then aqueous citrus peel extracts.

The production of citrus juice generates a large quantity of by-products, which are often discarded or used for animal feed. However, several studies have shown its richness in valuable compounds, namely organic acids. Thus, this work intended to valorize orange and lime peels as renewable sources of citric acid. An experimental design combining five levels of the independent variables time (2–45 min), ultrasonic power (50–500 W), and ethanol proportion (0–100%) was implemented and response surface methodology (RSM) was applied to optimize the extraction process. The UPLC-PDA analysis showed that orange peel presented a higher citric acid content than lime. For lime and orange peels, the extraction yield was maximized by sonicating at low power for 5.8 or 35.5 min, using a low ethanol proportion or only water as a solvent, respectively. Overall, optimal UAE conditions were defined for the sustainable extraction of citric acid from citrus by-products, thus contributing to its valorization and upcycling into natural food ingredients. [ABSTRACT FROM AUTHOR]

In this work, the use of natural organic wastes (orange and lemon peels) as sources of citric acid was evaluated along with the application of the photoelectro-Fenton (PEF) system under non-modified pH as a novel alternative to degrade a complex mixture of pharmaceuticals: sulfamethoxazole (SMX—7.90 × 10–5 mol/L) and trimethoprim (TMP—6.89 × 10–5 mol/L). The system was equipped with a carbon felt air diffusion cathode (GDE) and a Ti/IrO2 anode doped with SnO2 (DSA). A 3.6 × 10–5 mol/L solution of commercial citric acid was used as a reference. The pharmaceuticals' evolution in the mixture was followed by high-performance liquid chromatography (HPLC). The addition of natural products showed an efficient simultaneous degradation of the antibiotics (100% of SMX and TMP at 45 min and 90 min, respectively) similar to the performance produced by adding the commercial citric acid to the PEF system. Moreover, the addition of natural products allowed for an increment of biodegradability (100% removal of TOC by a modified Zahn Wellens test) and a decrease in ecotoxicity (0% in the bioassay with D. Magna) of the treated solutions. The antibacterial activity was eliminated after only 45 min of treatment, suggesting that the degradation by-products do not represent a significant risk to human health or the environment in general. Results suggest that, because of the efficient formation of Fe-citrate complexes, the PEF could be enhanced by the addition of natural organic wastes as a sustainable alternative ecological system for water contaminated pharmaceuticals. Additionally, the potential of reusing natural organic wastes has been exposed, contributing to an improved low-cost PEF by decreasing the environmental contamination produced by this type of waste. [ABSTRACT FROM AUTHOR]

In this work, a method based on ultra-high-performance liquid chromatography with a photodiode array detector (UPLC-PDA) was developed to comprehensively analyze phenolic compounds in peels of lime (Citrus × latifolia), lemon (Citrus limon), and rangpur lime (Citrus × limonia). The reverse-phase separation was achieved with a C18 fused-core column packed with the smallest particles commercially available (1.3 um). The method was successfully coupled with high-resolution mass spectrometry (HRMS), allowing the detection of 24 phenolic compounds and five limonoids in several other citrus peels species: key lime, orange and sweet orange, tangerine, and tangerine ponkan, proving the suitability for comprehensive analysis in citrus peel matrices. Additionally, the developed method was validated according to the Food and drug administration (FDA) and National Institute of Metrology Quality and Technology (INMETRO) criteria, demonstrating specificity, linearity, accuracy, and precision according to these guidelines. System suitability parameters such as resolution, tailoring, plate count were also verified.

Obtaining polyphenols from horticultural waste is an emerging trend that enables the valorization of resources and the recovery of value-added compounds. However, a pivotal point in the exploitation of these natural extracts is the assessment of their chemical stability. Hence, this study evaluates the effect of temperature storage (20 and −20 °C) and drying methods on the phenolic composition and antioxidant activity of clementine and lemon peel extracts, applying HPLC-DAD-MS, spectrophotometric methods, and chemometric tools. Vacuum-drying treatment at 60 °C proved to be rather suitable for retaining the highest antioxidant activity and the hesperidin, ferulic, and coumaric contents in clementine peel extracts. Lemon extracts showed an increase in phenolic acids after oven-drying at 40 °C, while hesperidin and rutin were sustained better at 60 °C. Hydroethanolic extracts stored for 90 days preserved antioxidant activity and showed an increase in the total phenolic and flavonoid contents in lemon peels, unlike in clementine peels. Additionally, more than 50% of the initial concentration was maintained up to 51 days, highlighting a half-life time of 71 days for hesperidin in lemon peels. Temperature was not significant in the preservation of the polyphenols evaluated, except for in rutin and gallic acid, thus, the extracts could be kept at 20 °C.

With growing consumer awareness, exploitation of renewable resources is cost-effective and environment friendly. This work examines the potential of citrus peels as natural antioxidants and antimicrobials for food preservation. Extraction yield, total soluble phenols and flavonoids of various citrus peels (sweet orange, lemon, tangerine and grapefruit) were optimized by varying the solvent type. While the highest extract yield (~16 ​g/100g) was obtained from the sweet orange peels in methanol, extraction with ethanol maximized the concentration of total phenols and flavonoids (~80 ​mg catechol equivalents/100 ​g dry weight). In addition, sweet orange peel extract showed the highest DPPH, ABTS and hydroxyl radical scavenging values. UPLC-ESI-MS/MS analysis of aqueous and ethanolic extracts of sweet orange peels revealed more than 40 polyphenolic compounds including phenolic acids and flavonoids, some of which have not been previously reported. The predominant polyphenols were narirutin, naringin, hesperetin-7-O-rutinoside naringenin, quinic acid, hesperetin, datiscetin-3-O-rutinoside and sakuranetin. The incorporation of sweet orange peel extract into two vegetable oils enhanced their oxidative stability. In addition, all citrus peel extracts possessed high antimicrobial activity against several food-borne pathogens, and the activity was highest for the sweet orange peel extract. Overall results suggested the great potential of sweet orange peels as natural antioxidant and antimicrobials, which can be efficiently extracted using a simple and low-cost method, for enhancing the storage stability and safety of vegetable oils.

This study comparatively evaluated inhibitory effect of essential oils (EOs) from tangerine and lemon peels on some enzymes [angiotensin‐converting enzyme (ACE), acetylcholinesterase (AChE), arginase, monoamine oxidase (MAO), phosphodiesterase‐5 (PDE‐5), adenosine deaminase (ADA) and 5'‐nucleotidase] related to erectile dysfunction (ED), as well as thiobarbituric acid reactive species (TBARs) level in isolated Wistar albino rats' penile homogenate. In addition, the chemical compositions of these EOs were characterized via gas chromatography coupled with flame ionization detector (GC‐FID). The result revealed that the studied EOs were able to inhibit these erectogenic enzymes and TBARs level in a dose‐dependent manner. The EOs were found to be rich in monoterpenes hydrocarbon. However, the major constituent in both oils was D‐limonene, 45.48% and 34.99% abundance in lemon and tangerine EOs, respectively. Other phytoconstituents detected in substantial amounts include the following: 4‐Vinyl‐2‐methoxyphenol (5.42% and 2.97%), N‐methyl‐D3‐Aziridine (6.58% and 10.01%) and Xanthotoxin (12.055 and 18.7%) for lemon and tangerine EOs, respectively. It is suggestive that these EOs owe their exceptional inhibitory capacities to the availability of these phytochemicals. Hence, their ability to inhibit ACE, AChE, arginase, MAO, PDE‐5, ADA and 5'‐nucleotidase activities, and TBARs level could be the possible mechanism by which the studied EOs exert their therapeutic potentials in the management of ED. [ABSTRACT FROM AUTHOR]

This study focused on the use of citrus bio-waste and obtention of silica-based materials through the sol-gel technique for promoting a greener and more sustainable catalysis. The solgel method is a versatile synthesis route characterized by the low temperatures the materials are synthesized in, which allows the incorporation of organic components. This method is carried out by acid or alkali hydrolysis combined with bio-waste, such as orange and lemon peels, generated as coproducts in the food processing industry. The main objective was to obtain silica-based materials from the precursor TEOS with different catalysts--acetic, citric and hydro-chloric acids and ammonium hydroxide--adding different percentages of lemon and orange peels in order to find the influence of bio-waste on acids/alkali precursor hydrolysis. This was to partially replace these catalysts for orange or lemon peels. The solids obtained were characterized with different techniques, such as SEM, FT-IR, potentiometric titration and XRD. SEM images were compared with pure silica obtained to contrast the morphology of the acidic and alkali hydrolysis. However, until now, few attempts have been made to highlight the renewability of reagents used in the synthesis or to incorporate bio-based catalytic processes on larger scales. [ABSTRACT FROM AUTHOR]

The bioactive components and bioactivities of citrus peel can be enhanced with microbial fermentation. Accordingly, this study investigated the ability of Aspergillus niger CGMCC3.6189 to accumulate flavonoids in Citrus reticulata peel powder (CRPP) by solid-state fermentation (SSF). Under the optimal SSF conditions including 80% moisture, 30 °C, pH 4.0, 4 × 107 spores/g d.w. CRPP, and 192 h, the total phenolic content (TPC), total flavonoid content (TFC), and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activities of fermented CRPP significantly increased by 70.0, 26.8, 64.9, and 71.6%, respectively. HPLC analysis showed that after fermentation, the contents of hesperidin, nobiletin, and tangeretin were significantly increased from 19.36, 6.31, and 2.91 mg/g to 28.23, 7.78, and 3.49 mg/g, respectively, while the contents of ferulic acid and narirutin were decreased under the optimal fermentation conditions. Fermentation time is one of the most important factors that affect the accumulation of flavonoids and antioxidant activity; however, extended fermentation time increased the darkness of CRPP color. Therefore, our study provides a feasible and effective SSF method to increase the bioactive components and the antioxidant activity of CRPP that may be used in food, nutraceutical, and medicinal industries.

Aging and agro-waste are major challenges. Natural ingredients are preferred in skincare. This study intended to isolate the essential oils (EO) from the leftover peels obtained from three commonly edible Citrus species fruit peels, namely Citrus paradisi (grapefruit), Citrus sinensis (sweet orange), and Citrus deliciosa (mandarin). Gas chromatography/mass spectrometry analysis identified volatile constituents in EO and headspace aroma. Multivariate analysis distinguished between the three species. The antiaging effects of Citrus EO were assessed in vitro and in silico, studying volatile interactions with target enzymes. C. sinensis peels had the highest oil yield, rich in monoterpenes. C. paradisi and C. deliciosa contained sesquiterpenes. Limonene dominated the hydrodistilled EO: 94.50% in C. paradisi, 96.80% in C. sinensis, and 80.66% in C. deliciosa. Unsupervised multivariate analysis of Citrus species revealed that  d-limonene, γ-terpinene, and β-pinene are the key phytochemical markers contributing to their diverse chemical composition. C. paradisi exhibited the highest enzyme inhibitory activity, with IC 50 values of 12.82, 27.58, and 18.16 µg/mL for tyrosinase, elastase, and collagenase, respectively. In silico studies showed that the volatiles can inhibit the tested antiaging enzymes. According to these findings, the investigated agro-waste might slow aging in skin care., (© 2024 Deutsche Pharmazeutische Gesellschaft.)

The bioactive phytochemicals derived from citrus wastes are considered to have various physiological and biological activities that may be potentially helpful in nutraceutical, pharmaceutical, and processed food industries. This study assessed the anti-Fusarium and antioxidant potential and chemical constituents of essential oil extracted from the peels of Citrus paradisi, Citrus sinensis, and Citrus aurantium. Phytochemical screening by Gas chromatography identified 24, 26, and 39 constituents in Citrus paradisi, Citrus sinensis, and Citrus aurantium, respectively. Amongst which, limonene (84-87 %) was found to be present in major proportion followed by other major components like a-myrcene, geranial, (+)-valencene, a-pinene, and neral. The estimation of polyphenol contents (PPC) (1.041±0.04 - 7.705±0.26 GAE µg/5mg) and the free radical scavenging activity of these major chemical components was determined by 1,1-diphenyl-2-picrylhydrazyl free radical scavenging ability (IC50: 0.71±0.02-2.99±0.1 µg, and reducing power (RP) (0.75±0.026-1.972±0.067). Anti-Fusarium activity was evaluated against two major food spoilage Fusarium species namely, Fusarium graminearum and Fusarium culmorum. Dose-dependent activity of growth inhibition effect of essential oils was observed. Citrus aurantium peel essential oil proved to be most effective with 100% inhibition of F. graminearum. [ABSTRACT FROM AUTHOR]

Citrus peel, a fruit-processing waste, is a substantial source of naturally occurring health-promoting compounds, including polyphenols, and has great potential as a dietary supplement for enhancing the functional properties of food. The present work aimed to investigate the effects of sour orange (SO), sweet orange (SWO), and lemon (LO) peels on the typical physiochemical, antioxidant, antibacterial, and probiotic properties of synbiotic yoghurt fermented by acidophilus-bifidus-thermophilus (ABT)-type cultures during cold storage (0–28 days). High-performance liquid chromatography-diode array detection (HPLC-DAD) analysis showed that the total phenolic content in the SO peel were more than 2-fold higher than that in the SWO and LO peel. The predominant phenolic compounds were myricetin (2.10 mg/g dry weight) and o-coumaric acid (1.13 mg/g) in SO peel, benzoic acid (0.81 mg/g) and naringin (0.72 mg/g) in SWO peel, and benzoic acid (0.76 mg/g) and quercetin (0.36 mg/g) in LO peel. Only 0.5% (w/w) of citrus peel addition did not reduce the overall acceptance of ABT synbiotic yoghurt but led to increased acidity and decreased moisture during cold storage (14 and 28 days). Additionally, compared to control samples without citrus peel addition, supplementation with citrus peels improved the antioxidant property of the ABT synbiotic yoghurt. ABT milks with SO and SWO peel addition had significantly stronger DPPH radical scavenging activities than that with LO peel addition (p < 0.05). Antibacterial analysis of ABT synbiotic yoghurt with citrus peel addition showed that the diameters of inhibition zones against S. aureus, B. subtilis, and E. coli increased by 0.6–1.9 mm relative to the control groups, suggesting the enhancement of antibacterial activities by citrus peels. The viabilities of probiotic starter cultures (L. acidophilus, S. thermophilus, and Bifidobacterial sp.) were also enhanced by the incorporation of citrus peels in synbiotic yoghurt during cold storage. Hence, our results suggest that citrus peels, especially SO and SWO peels, could be recommended as a promising multifunctional additive for the development of probiotic and synbiotic yoghurt with enhanced antioxidant and antibacterial properties, as well as probiotic viability.

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Diabetes mellitus (DM) has a worldwide prevalence with very alarming situation in low-income and developing countries including Pakistan. During this project, we investigated peels of two commonly used Citrus species, i.e., C. sinensis and hybrid Citrus (C. nobilis and C. delicense) for their antioxidant, antidiabetic, antiglycation, antimicrobial and anti-inflammatory activities. Initially the peels were dried and extracted with various solvents. Then, HPLC and ATR-FTIR analysis was performed and finally the extracts and fractions were analyzed for their biological properties. The HPLC and ATR-FTIR data showed the presence of phenolics and flavonoids. In C. sinensis peels, high concentration of phenolics (87.3 ± 0.11 mg/g GAE) were observed in ethyl acetate part followed by methanolic fraction (72.5 ± 0.12 mg/gGAE). Both extracts exhibited strong antioxidant activity, antimicrobial and anti-biofilm properties. In Advanced Glycation End Products (AGEs) assay, total extract of C. sinensis showed moderate (IC50 = 1.23 mg/mL) activity. All tested fractions were active in respect of α-glucosidase inhibition, whereas in 15-lox assay, only n-hexane fraction presented excellent activity (90%). On the other hand, in case of hybrid Citrus, a moderate inhibition was found in the case of total extract (IC50 = 0.25 mg/mL). Among fractions, highest inhibition was noticed for the methanolic part of crude extract (IC50 = 0.10 mg/mL). Both the total crude extract (IC50 = 0.23 mg/ml) and methanolic part of plant extract (IC50 =0.36 mg/ml) showed α-glucosidase inhibition, whereas only moderate 15-lox inhibition was observed. [ABSTRACT FROM AUTHOR]

The production of citrus juice generates a large quantity of by-products, which are often discarded or used for animal feed. However, several studies have shown its richness in valuable compounds, namely organic acids. Thus, this work intended to valorize orange and lime peels as renewable sources of citric acid. An experimental design combining five levels of the independent variables time (2–45 min), ultrasonic power (50–500 W), and ethanol proportion (0–100%) was implemented and response surface methodology (RSM) was applied to optimize the extraction process. The UPLC-PDA analysis showed that orange peel presented a higher citric acid content than lime. For lime and orange peels, the extraction yield was maximized by sonicating at low power for 5.8 or 35.5 min, using a low ethanol proportion or only water as a solvent, respectively. Overall, optimal UAE conditions were defined for the sustainable extraction of citric acid from citrus by-products, thus contributing to its valorization and upcycling into natural food ingredients.

The orange tree (Citrus sinensis) is a species of fruit shrubs of the Rutaceae family. Essential oils from citrus peels are widely used in various agro-food and pharmaceutical preparations and hence they must be recovered using green extraction methods. In this study, we compare the efficiency of five extraction techniques (conventional hydro-distillation (HD), Salt-assisted extraction by HD (S-HD), Ultrasound-assisted extraction by HD (US-HD), Enzymes-assisted extraction by HD (E-HD), and Solvent-free microwave extraction (SFME)) for the extraction of essential oil from Citrus sinensis peels. The essential oils were compared with regard to their chemical compositions, light microscopy analysis, total energy consumption, and antioxidant activity. GC/MS analysis allowed the identification of 28 compounds in the different essential oils. The principal identified component was limonene (86.7 %, 87.9 %, 88.2 %, 88.3 %, 85.4 % for HD, S-HD, US-HD, E-HD, and SFME, respectively), followed by β-pinene, sabinene, linalool and α-terpineol. The obtained essential oils were analyzed for their antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. Results indicated that essential oil extracted by SFME showed the highest antioxidant activity (IC50 = 0.0175 mg/ml) and extraction yield (3.58 % ± 0.05) consuming lower energy (0.312 kW h-1) in a shorter extraction time (30 min) comparing with the other tested techniques. Hence, the SFME would be an interesting green method for the recovery of essential oil from C. sinensis peels useful in agro-food, cosmetic, and pharmaceutical preparations as an alternative for undesirable chemical additives. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to determine the physico-chemical and antioxidant properties of bitter orange (Citrus aurantium), bergamot (Citrus bergamia) and grapefruit (Citrus paradisi) peels and jams traditionally produced from them. Total dry matter, water soluble dry matter, pH and titratable acidity values of citrus peel jams were determined between 78.23 -- 80.01 g/100 g, 70.15 - 70.87 °Bx, 3.36 - 3.49 and 0.26 -- 0.27%, respectively. The total phenolic contents of citrus peel jams were determined between 22.38 - 38.21 mg GAE/100 g, and the total flavonoid contents were determined as 2.45 - 6.30 mg CE/100. With the processing of the peels into jam, the ascorbic acid content decreased by 82.47 - 84.50% and was determined as 13.91 - 16.43 mg/100 g. The highest amount of total phenolic was found in grapefruit peel jam. It was determined that bitter orange peel jam has the highest total flavonoid and ascorbic acid content. DPPH radical scavenging activity decreased significantly with the jam processing. [ABSTRACT FROM AUTHOR]

In this study, 126 Cobb 500 commercial broiler chicks were fed a control basal (C) diet (corn-soy basal diet on an ad libitum basis) alone or with two different citrus peel. A completely randomized design with 42 chickens was used to investigate the effect of 2% orange peel (OP) or 2% grapefruit peel (GP) on broiler performances and thigh meat quality. The treatment containing 2% OP had a significant (P<0.05) effect on broiler performances. At the end of the trial (d 42), 6 broiler chickens per group were sampled for determination of thigh meat color, TPA, proximate chemical composition and primary oxidation products. Rations containing up to 2% OP and GP had a slight effect on proximate composition of raw broiler thigh meat. The Cie-Lab parameters have changed significantly (P<0.05) through in an increase in lightness, L*, and yellowness, b*, but they did not affect redness, a*. The color difference, ΔE*, between the OP and GP samples vs. C samples, was highlighted. The results of Warner Bratzler mechanical test showed a significant (P<0.05) increase of hardness in OP group while the cohesiveness was significantly (P<0.05) higher in GP group compared with C group. Chewiness was significantly (P<0.05) higher in both experimental treatment while resilience and springiness were similar in all three treatments. Regarding the primary oxidation products, conjugated diene (CD) and conjugated trienes (CT) of broiler thigh meat after 7 days of refrigeration were significantly (P<0.05) lowered in both experimental treatments showing that degradation process was delayed in thigh meat from experimental treatments. [ABSTRACT FROM AUTHOR]

To meet the increasing demand for agricultural products the use of agricultural pesticides increased in the second half of the twentieth century, especially pesticides of high toxicity. As a result of the environmental damage caused by the misusing of pesticides, calls were increasing for preserving the components of biological diversity and environmental balance, and for adopting organic agriculture. In the other hand in the last two centuries a huge revolution in the quantities of consumed food were pointed and as a result the rubbish increased. This study aimed at reducing the percentage of organic garbage resulted from homes and fresh juice restaurants, then recycling it in the form of pesticide made from different types of citruses. In this study two types of citrus: lemon and orange were used. Large quantities of their peels were collected and dried at room temperature; each one kilo gram of dried peel was produced from ten kilo grams of wet peels. After three weeks of drying the dried peels were smashed to get fine powder, finally those powders were treated in the lab by using steam desalination and by using Methyl Ether to produce essential oils. In addition to the technical part, the economical analysis of using essential oils as an insecticide, anti- fungal, or anti-bacterial were applied as a second part of this study. Nevertheless, the social part included a questioner was covered local families by asking the interviewees about the knowledge of recycling the peels of citrus and their ability to collect the peels for recycling. Two scenarios were analyzed for the economic part; first one by considering the cost of peels was zero the second one that the peels were being bought from different families. Finally, the result of economic part was indicated that the extraction of essential oil from citrus peels drain extra income if specific quantity of peels was collected. [ABSTRACT FROM AUTHOR]

• Acetic acid activated Citrus peels and calcium alginate spherical beads were facilely prepared. • Prepared adsorbent is proven effective in adsorbing the cationic dyes. • Maximum MB and CV adsorption capacities were 923 and 881 mg/g. • Regeneration tests show that the adsorbents have excellent reusability potential. Acetic acid-modified powdered and encapsulated cellulose-based modified citrus peels CPAA and CPAA-A were easily prepared and characterized using FTIR, DRX, BET, SEM, pH PZC and Boehm analysis, to investigate the single and binary adsorption of MB and CV dyes. Many parameters that affect adsorption phenomena were investigated: pH (3–11) of initial dyes solution, contact time, and initial dyes concentration (25–300 mg·L−1). Kinetics modeling shows that the adsorption of MB and CV onto adsorbents was well described by pseudo-first-order. CV and MB adsorption capacities on CPAA-A were respectively 881.36 and 923.07 mg·g−1 found by Langmuir model showing homogeneous and monolayer adsorption of MB and CV. The removal of dyes in the binary system shows that adsorption was slightly or nether affected by the simultaneous presence of the dyes in solution. CPAA-A and CPAA show very high adsorption capacities proving to be very useful in the field of water treatment in single or binary systems. [ABSTRACT FROM AUTHOR]

This study reveals variation in phenolic acids and antimicrobial attributes of peel extracts from ripe and unripe lisbon lemon [Citrus limon (L.) Osbeck] fruit. Total phenolic contents in ripened lemon peels were significantly (p < 0.05) higher (138.66–344.33 GAE mg/g DW) than the unripen lemon peel (122.33–277.10 GAE mg/g DW). The total amount of individual phenolic acids as analyzed by RP-HPLC in unripe and ripened peels ranged from 3.8 ± 2.2 to 1453.6 ± 66.4 and 3.4 ± 1.8 to 1772 ± 64 mg/kg, respectively with gallic, caffeic, cinnamic, syringic, vanilic, vanillin, p-coumaric, m-coumaric and o-coumaric acids as the main compounds detected. As per disk diffusion measurement, different solvent (methanol, ethyl acetate and chloroform) extracts from ripened and unripe lemon peel exhibited considerable antimicrobial activity against four bacterial strains including Salmonella typhimurium, Bacillus subtilus, Escherichia coli and Staphylococcus aureus with 50% chloroform extracts having the best potential. The composition of phenolics and antimicrobial activity of tested peels varied notably in relation to extraction solvents and fruit maturity stages. Overall, the present results support potential uses of limon peels as a natural source of high-value phenolics/antimicrobial agents for nutra-pharmaceutical developments. [ABSTRACT FROM AUTHOR]

Citrus fruits are known to contribute towards health considering their nutritional composition as well as bioactive ingredients. Although utilized at the industrial level, household-level consumption of citrus peel is not a common concept. The current study was conducted to compare the composition of different citrus fruits as well as to compare their peels and pulps composition. Three samples of citrus fruits (oranges (Citrus Sinensis) [sample O], lemons (Citrus Limons) [sample L], and grapefruits (Citrus Paradisi) [sample G]) were selected. Two variables; type of fruit with three categories (O vs L vs G) and part of the fruit with two categories (peel vs pulp) were studied. Proximate contents (AOAC methods), antioxidant activity (modified DPPH bleaching), Ferrous ion chelating activity, and total phenol content (Folin-Ciocalteu method) were determined for each sample. One-way ANOVA and post hoc analysis was run to note down differences among various samples. Except for moisture and fat, all other proximate components showed significantly higher amounts in peels compared with pulp. Fiber and ash contents were significantly higher in peels compared with pulps for all three fruits with a mean difference of L=10.1g, O= 9.29g, G= 10.19g for fiber and L= 0.18g, O=0.37g, G=0.10g for ash. Protein and carbohydrate were found in higher quantity in peels of Samples O and L (mean difference L=0.38g, O=0.15g for protein and L=8.1g, O=13.86g) while significantly lower in the peel of sample G (mean difference protein=1.14g, carbohydrate=0.98g). Antioxidant capacity, total phenolic content and chelating activity were found to be significantly higher in peels of L, O, and G though these contents were not significantly correlated (p>0.05) to one another. The findings of this study show that citrus fruits are a rich source of nutrients as well as phytochemicals. The peels of citrus fruits can serve as better sources of antioxidants, phenolic content, chelating properties, and some nutrients than their pulps. This study provides evidence for the benefits of utilizing peels at the household level while reducing food waste. [ABSTRACT FROM AUTHOR]

Citrus processing industry generates the large amount of byproducts, which are rich in polyphenols that have high antioxidant properties. These polyphenols can be extracted and utilized in different applications. In present investigation, comparative study was undertaken using maceration (M) and ultrasound assisted extraction (UAE) for the efficient extraction of polyphenols from citrus peels of different cultivars such as 'kinnow mandarin' (Citrus reticulata) and 'mousambi' (Citrus limetta). The total phenols (28.30 mg/GAE g dw), flavonoids (4.40 mg/CE g dw) and DPPH radical scavenging activity (48.23%) were attained from kinnow mandarin peels whereas total phenols (21.99 mg/GAE g dw), flavonoids (2.07 mg/CE g dw) and DPPH radical scavenging activity (39.73%) were obtained from mousambi peels using UAE method. Therefore, the results indicated the efficiency of UAE method as compared to maceration technique for the extraction of polyphenols in terms of high yield and their antioxidant properties. [ABSTRACT FROM AUTHOR]

The gel properties of pectin are significantly connected with its molecular structure. In this paper, we investigated the relationship between low methoxyl pectin (LMP) molecular structure and gel strength in the same degree of esterification (DE) range. LMP with DE of 31% ± 2% was prepared from citrus peels by acid, alkaline, enzymatic, and citric acid/sodium citrate solution methods. And based on data from monosaccharide composition, Mw, and NMR spectroscopy, the proportion of structural regions was speculated. The result revealed that C-LMP (pectin de-esterified by citric acid/sodium citrate solution method) was a highly branched macromolecular polysaccharide with short HG and enriched RG-I, with HG and RG-I proportions of 19.37% and 76.96%. According to the gel property investigation, of all the LMP samples, A-LMP-0.7 (pectin de-esterified by acid method at pH 0.7), which possessed lengthy HG and enriched RG-I domain, exhibited the best gel strength. C-LMP, A-LMP-0.5 (pectin de-esterified by acid method at pH 0.5), and B-LMP (pectin de-esterified by alkaline) failed to form a complete gel due to the low HG linearity, sparse RG-I and low Mw, respectively. The purposed mechanism for the effects of low methoxyl pectin (LMP) chain conformation on its gel structure. [Display omitted] • LMPs with DE of 31% ± 2% was prepared by different de-esterification methods. • HMP had the longest HG and largest Mw. • LMP obtained by alkaline de-esterification possessed the lowest Mw. • LMP prepared by buffer salt de-esterification had short HG and enriched RG-II. • LMP de-esterified by acid method exhibited the most stable gel network structure. [ABSTRACT FROM AUTHOR]

Sorptive properties of peels of citrus fruit (grapefruit, mandarin, orange, and lemon) were tested against cationic dyes popular in the industry: BV10 and BR46, and the kinetics of colorant sorption was determined. The experimental data obtained were matched to the pseudo-first/second-order model and to the intramolecular diffusion model. The maximum sorption capacity of citrus fruit peel (Langmuir, Langmuir 2, and Freundlich isotherm) was determined as well. The maximum sorption capacity of BR46, amounting for Q = 57.04 mg/g, was exhibited by orange peel, whereas the best sorbent for BV10 turned out to be lemon peel (Q = 5.66 mg/g). [ABSTRACT FROM AUTHOR]

• First simultaneous isolation of six polymethoxyflavones (PMFs) from citrus peels. • New application of high performance counter current chromatography (HPCCC). • Contribution to broadening the application of HPCCC in the field of food chemistry. • Perspectives for large scale separation of PMFs for biological property evaluation. Successful isolation of polymethoxyflavones (PMFs) from citrus peels has led to numerous evaluations of PMFs in a broad spectrum of biological activities, such as inhibition of chronic inflammation, cancer prevention and anti-atherogenic properties. Recent reports associated with the health promoting properties of PMFs in citrus fruits have dramatically increased. However, the limiting factor in animal and human study of PMFs is still the supply of pure PMFs, such as tangeretin, nobiletin, sinensetin and 3,5,6,7,3′,4′-hexamethoxyflavone. Herein, we introduce the newly developed efficient separation method using high-performance counter-current chromatography (HPCCC) in isolating multiple pure single PMFs simultaneously in one cycle process. With the smallest preparation loop on the semi-preparative HPCCC instrument, the optimized solvent system of hexanes/ethyl acetate/methanol/water resulted in the isolation of pure sinensetin, tangeretin, nobiletin, 3,5,6,7,3′,4′-hexamethoxyflavone, 5,6,7,4′-tetramethoxyflavone and 3,5,6,7,8,3′,4′-heptamethoxyflavone directly from crude sweet orange peel extract in one cycle of separation process by HPCCC in the mode of reverse phase. The purity of each of the six isolated PMFs is greater than 96.6% analyzed by high-performance liquid chromatography and proton nuclear magnetic resonance. Scale-up and high purity of individual PMFs can be separated by using a large separation loop in preparative HPCCC model. The renovated HPCCC methodology can be practically used in natural product isolation and consequent biological property evaluation. [ABSTRACT FROM AUTHOR]

Near Infrared (NIR) method combined with chemometrics was utilized to achieve the target of deeper insight into the chemical diversity and to discriminate the different species and chemovarieties of Citrus peels. Unsupervised principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used for comparing of samples. A clear separation among the eight investigated species and cultivars was revealed, except for the red and white C. paradisi peels samples. Furthermore, fingerprint-bioflavonoids content relationship was modeled by partial least squares regression. A practical approach based on reflectance NIR measurements and partial least squares regression (PLSR) was demonstrated for quantitative determination of the bioflavonoids hesperidin and diosmin and compared to other reported methods. The regression coefficients (R2) between predicted values and pre-determined hesperidin and diosmin content were >0.98, indicating the possibility to simultaneously quantify hesperidin and diosmin in Citrus samples directly from NIR measurements using an adequate PLS regression. Citrus sinensis followed by Citrus reticulata samples were found the most enriched in the bioflavonoids hesperidin and diosmin. NIR-multivariate analysis can therefore be used for discrimination of different varieties and selection of citrus species with desired amounts of specific bioflavonoids which could successfully be analyzed in such complex plant matrices which can prove useful for further pharmaceutical implementation. Unlabelled Image • 73 citrus peel samples were evaluated using NIR-chemometrics. • PCA, HCA were used for comparing and classification of samples. • Clear separation among the eight investigated species and cultivars was revealed. • Fingerprint-diosmin and hesperidin content relationship was modeled by PLSR. • PLSR models successfully used for prediction of bioflavonoids in complex matrices. [ABSTRACT FROM AUTHOR]

Cellulose is the most common polymer in the world, formed by β-1,4 linked glucopyranose units. In this study, citrus peels (lemon, mandarin, orange and grapefruit) were used for the production of bacterial cellulose (BC). The peels were hydrolyzed with dilute acid and hydrolysates were used for BC production. The production of BC was carried out at 28–32 °C for 21 days under static conditions with Komagataeibacter hansenii GA2016. BC yields were found to be between 2.06 and 3.92%. It was found that the FTIR spectra of the BCs produced in citrus peel hydrolysates were similar to BC produced in the commercially available nutrients. The result of this study showed that all the BCs produced from citrus peels were characterized to have high water holding capacity, thin fiber diameter, high the thermal stability and high crystallinity. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Citrus peels have been reported useful in folk medicine for the management of cardiovascular diseases, but there is dearth of information on the possible mechanisms for their therapeutic action. The aim of this study was to investigate the effect of methanolic extracts from some citrus [lime (Citrus limon), tangerine (Citrus reticulata), shaddock (Citrus maxima)] peels on some enzymes relevant to the management of cardiovascular diseases [monoamine oxidase (MAO), phosphodiesterase-5 (PDE-5) and angiotensin-1-converting enzyme (ACE)]. Methods: Effect of methanolic extracts of lime, tangerine and shaddock peels on MAO, PDE-5 and ACE were carried out using standard methods. In addition, the ability of the extracts to prevent oxidative damage in rat heart homogenates was also investigated. Finally, the total polyphenol content of extracts was determined. Results: The results revealed that methanolic extracts of lime, tangerine and shaddock peels inhibited MAO, PDE-5, ACE and pro-oxidants induced lipid peroxidation in rat heart homogenate in a concentration-dependent manner. Conclusions: Findings in this study revealed citrus peel methanolic extracts as natural inhibitor of enzymes (MAO, PDE-5 and ACE) implicated in cardiovascular diseases. Therefore, citrus peels could help in the management of cardiovascular diseases possibly through inhibition of these enzymes. [ABSTRACT FROM AUTHOR]