Mandarin Peel Research Articles

Significant improved co-extraction of hesperidin and narirutin from mandarin peel, a food processing by-product, based on statistical predictive models

Mandarin peel (MP) from food processing contains useful ingredients such as flavonoids, thus valorization strategies for MP are expected to be the first step in realizing a sustainable society. This study designed the co-extraction of two flavonoids (hesperidin and narirutin) from MP based on a multiple regression model with extraction temperature, time, and solid loading as the major variables. Numerical optimization determined that the optimal condition to maximize the extraction of both flavonoids was 60.0 °C, 100.9 min, and 95.7 g/L. Under this condition, the experimental results showed that the recovery of hesperidin and narirutin achieved 31.9 and 14.8 mg/g-biomass, respectively, which were in over 90% agreement with the predicted values. Total flavonoid content of MP extract was 81.9 mg/g-biomass, and antioxidant activity (ABTS EC50: 2.8 μg/mL) was similar to ascorbic acid. Previous studies have reported the identification of major flavonoids in MP, however, this is the first to achieve maximum recovery of two targeted flavonoids. In particular, the innovation of this study was the optimization of co-extraction, which demonstrated the high potential of MP extract as a natural antioxidant.

Effect of H2O2/ascorbic acid degradation and gradient ethanol precipitation on the physicochemical properties and biological activities of pectin polysaccharides from Satsuma Mandarin

In this work, three degraded polysaccharides (DMPP-40, DMPP-60, DMPP-80) were successfully obtained by H2O2/ascorbic acid degradation and gradient ethanol precipitation from Satsuma mandarin peel pectin (MPP), and their physicochemical properties, antioxidant and prebiotic activities were investigated. The molecular weight of MPP, DMPP-40, DMPP-60, DMPP-80 were determined to be 336.83 ± 10.57, 18.93 ± 0.54, 26.07 ± 0.83 and 8.71 ± 0.27 kDa, respectively. The ethanol concentration significantly affected the physicochemical properties of DMPPs. DMPP-60 showed the highest yield (69.07 %) and uronic acid content (64.85 %), DMPP-80 showed the lowest molecular weight (8.71 kDa), and the composition and proportion of monosaccharides of DMPPs were significantly different. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR) confirmed that DMPPs exhibited similar functional groups, while X-ray diffraction (XRD) indicated that DMPP-40 possessed some crystallographic sequences. Scanning electron microscopy (SEM) images directly verified the fragmented structure and reduced surface area of DMPPs. Besides, the H2O2/ascorbic acid treatment could obviously reduce the apparent viscosity and thermal stability of MPP. Meanwhile, the results of bioactivity assay showed that DMPPs possessed better antioxidant activity and probiotics pro-proliferative effects compared with MPP. DMPP-80 could significantly inhibit lipopolysaccharides (LPS)-stimulated production of inflammatory factors (including nitric oxide (NO), interleukin (IL)-6, tumor necrosis factor (TNF)-α and interleukin (IL)-1β) in RAW264.7 cells. Results suggest that the H2O2/ascorbic acid combined with gradient ethanol precipitation has potential applications in degradation and separation of MPP to improve its biological activities.

Mandarin Peels-Derived Carbon Dots: A Multifaceted Fluorescent Probe for Cu(II) Detection in Tap and Drinking Water Samples.

Carbon dots (CDs) derived from mandarin peel biochar (MBC) at different pyrolysis temperatures (200, 400, 600, and 800 °C) have been synthesized and characterized. This high-value transformation of waste materials into fluorescent nanoprobes for environmental monitoring represents a step forward towards a circular economy. In this itinerary, CDs produced via one-pot hydrothermal synthesis were utilized for the detection of copper (II) ions. The study looked at the spectroscopic features of biochar-derived CDs. The selectivity of CDs obtained from biochar following carbonization at 400 °C (MBC400-CDs towards various heavy metal ions resulted in considerable fluorescence quenching with copper (II) ions, showcasing their potential as selective detectors. Transmission electron microscopic (TEM) analysis validated the MBC-CDs' consistent spherical shape, with a particle size of <3 nm. The Plackett-Burman Design (PBD) was used to study three elements that influence the F0/F ratio, with the best ratio obtained with a pH of 10, for 10 min, and an aqueous reaction medium. Cu (II) was detected over a dynamic range of 4.9-197.5 μM and limit of detection (LOD) of 0.01 μM. Validation testing proved the accuracy and precision for evaluating tap and mountain waters with great selectivity and no interference from coexisting metal ions.

Effects of mandarin peel powder on growth, biochemical, immune, and intestinal health in Oreochromis niloticus at suboptimal temperatures

This 60-day study aimed to examine the efficacy of a diet supplemented with mandarin peel powder (MP) in enhancing the health and survival of Oreochromis niloticus under suboptimal temperature conditions (21 ℃). One hundred and eighty Nile tilapia fish (22.51 ± 0.04 g) were randomly distributed into four experimental groups; each of 3 replicates (15 fish per replicate). The first group (CONT) received a basal diet without MP. The second (MP10%), third (MP15%), and fourth (MP20%) groups were fed diets containing 10, 15, and 20% MP powder, respectively. At the end of the feeding trail, growth performance, serum growth hormone, α-amylase enzyme, lysozyme activity, nitric oxide, protease activity, globulin, serum levels of IL-1ß, antioxidant status, and intestinal histology were measured. The results showed insignificant differences between CONT, MP15%, and MP20% groups in the final body weight and specific growth rate. The growth hormones in the MP15% and MP20% groups did not show a significant difference compared to fish fed a normal basal diet (CONT). However, the amylase enzymes were significantly greater in both groups. The MP20% and MP15% groups showed a significant increase in antioxidant, lysozyme, nitric oxide, and protease activities compared to CONT. The results also showed that fish that were fed a diet with MP had significantly less of the pro-inflammatory cytokine interleukin-1 beta, and their intestinal villi got wider, especially in the MP20% group. It could be concluded that feeding tilapia on a diet with 20% MP is an effective strategy to improve their health when the temperature is below 21 °C. This is because the fish exhibit higher levels of antioxidant activity, reduced pro-inflammatory responses, and improved intestinal health without difference in the growth performance in compared to control group.

Improved Sugar Recovery from Mandarin Peel under Optimal Enzymatic Hydrolysis Conditions and Application to Bioethanol Production

Improved Sugar Recovery from Mandarin Peel under Optimal Enzymatic Hydrolysis Conditions and Application to Bioethanol Production

Effect of coatings containing 1-methylcyclopropane or mandarin peel extract on the freshness and metabolic profiles of cold stored strawberry

The application of coatings is a strategy for maintaining the freshness of highly perishable fruits. This research aimed to evaluate the quality indices of strawberries (Amaou) coated with new coatings based on the sodium carboxymethyl cellulose (CMC) and cellulose nanofibres (CNF) with incorporated mandarin peel extract (ME) or 1-methylcyclopropene (1-MCP) during storage at 20days at 5 °C and 85% relative humidity (RH). Dissolving the coating solution containing ME in 1-MCP maintained its colour for up to 50 days. Coatings enhanced with ME and/or 1-MCP maintained fresh strawberries more effectively than the control, reducing weight loss and maintaining firmness, total soluble solids (TSS), citric acid, colour, and total phenolic content. The CCM2–2 coating solution showed superior effects on the weight loss and relative percentages of strawberry metabolites compared to the other coatings, as confirmed by the different components.

Extraction and characterization of phenolic compounds from mandarin peels using conventional and green techniques: a comparative study

The exploration of citrus waste valorization extends beyond its environmental benefits to encompass potential health implications, particularly in cancer prevention. The bioactive compounds extracted from citrus waste, notably polyphenols like quercetin, gallic acid, hesperidin, and ferulic acid, hold promising anti-cancer properties. Research suggests that these compounds exhibit potent antioxidant and anti-inflammatory effects, which are integral in combating carcinogenesis. Quercetin, a flavonoid abundantly found in citrus extracts, has garnered attention for its ability to inhibit cancer cell proliferation and induce apoptosis, thereby impeding tumor growth. Gallic acid, another prevalent compound, demonstrates anticancer potential through its modulation of signaling pathways associated with cell survival and proliferation. Hesperidin, known for its antioxidative properties, has shown promise in suppressing tumor growth and metastasis by targeting various molecular pathways involved in cancer progression. Ferulic acid, renowned for its anti-inflammatory and antioxidant activities, exhibits chemopreventive effects by inhibiting carcinogen activation and promoting detoxification processes within the body. The present study compares conventional (soxhlet, maceration) and non-conventional (ultrasound, microwave) techniques to obtain these polyphenols from mandarin peels. The maximum total phenolic content of 3.78 mg GAE/ g dry peels and DPPH activity of 69.89% was observed using 80% methanol and ultrasound assisted extraction. The presence of these compounds was confirmed using advanced analytical methods such as FT-IR and HPLC. The phenolic compounds (mg/g dry peels) such as gallic acid (0.29 ± 1.08), p-coumaric acid (0.17 ± 0.52), chlorogenic acid (0.30 ± 0.56), ferulic acid (1.49 ± 1.36), hesperidin (1.34 ± 0.51), naringenin (0.56 ± 0.94), and quercetin (0.33 ± 1.02), observed during UAE were 25–35% higher values compared to other techniques. By harnessing the bioactive potential of citrus waste-derived compounds, particularly for cancer prevention, this study contributes to both environmental sustainability and human health enhancement, paving the way for innovative strategies in functional food development and nutraceutical applications.

Mandarin biochar-CO-TETA was utilized for Acid Red 73 dye adsorption from water, and its isotherm and kinetic studies were investigated

Environmental pollution is a major issue today due to the release of dyestuff waste into the environment through industrial wastewater. There is a need for affordable and effective adsorbents to remove harmful dyes from industrial waste. In this study, Mandarin biochar-CO-TETA (MBCOT) adsorbent was prepared and used to remove Acid Red 73 (AR73) dye from aqueous solutions. The efficiency of dye removal was influenced by various factors such as solution pH, contact time, initial AR73 dye concentration, and MBCOT dosage. All experiments were conducted at 25 ± 2 °C, and the optimal pH was determined to be 1.5. The optimal conditions for dye removal were found to be an AR73 dye concentration of 100 mg/L, an MBCOT dosage of 1.5 g/L, and a contact time of 150 min, resulting in a 98.08% removal rate. Various models such as pseudo-first-order (PFO), pseudo-second-order (PSO), film diffusion (FD), and intraparticle diffusion (IPD) were used to determine the adsorption kinetics of AR73 dye onto MBCOT. The results showed that the PSO model best explains the AR73 dye adsorption. Furthermore, Langmuir and Freundlich's isotherm models were studied to explain the adsorption mechanism using experimental data. The adsorption capacities at equilibrium (qe) in eliminating AR73 dye varied from 92.05 to 32.15, 128.9 to 65.39, 129.25 to 91.69, 123.73 to 111.77, and 130.54 to 125.01 mg/g. The maximum adsorption capacity (Qm) was found to be 140.85 mg/g. In conclusion, this study demonstrates that biochar produced from mandarin peels has the potential to be an effective and promising adsorbent for removing AR73 dye from water.

CsERF003 enhanced peel coloration by promoting both chlorophyll degradation and carotenoid accumulation in citrus

Uneven coloration is a common phenomenon in citrus fruit during the ripening stage, as affects the appearance and economic value of the fruit. The elevated expression of CsERF003 during the degreening process of both lemon and satsuma mandarin peels was reported. In this research, a similar performance of CsERF003 in the pericarp coloration process was also identified by transcriptome analysis of 'Fengjie 72–1' navel orange and Lane Late navel orange. However, the regulatory mechanism of CsERF003 is not clear yet. Overexpression of CsERF003 could deepen the color of citrus callus and promote peel degreening of Newhall navel orange, which was attributed to the upregulation of genes involved in chlorophyll degradation and carotenoid synthesis. Furthermore, CsERF003 acted as an activator to promote the expression of CsLCYE, but couldn’t activate the expression of CsLCYB1 and CsLCYB2; CsERF003 could also bind to the promoter of CsSGR to activate its expression. Together, our findings shed light on the regulatory mechanism of CsERF003 in chlorophyll degradation and carotenoid accumulation, particularly in the α-branch of carotenoid metabolism. These insights offer valuable perspectives for the genetic enhancement of peel coloration in citrus.

Antioxidant activities of lemon and mandarin peel extracts as natural preservatives in ghee (butter oil) stored at different storage temperatures

Using natural preservatives in ghee and fat-rich products has great economic importance as it can minimize adverse effects on human health and improve the marketing prospects of products. The present study aimed to use lemon (Citrus lemon L.) and mandarin (Citrus reticulata L.) peel extracts as natural preservatives instead of synthetic antioxidants of butylated hydroxyanisole (BHA) to retard the oxidation of ghee during accelerated storage at various temperatures. Antioxidant activities of lemon peel extracts (LPE), mandarin peel extracts (MPE) and BHA in ghee samples stored at different storage temperatures (T1: 5±2°C, T2: 25±2°C, T3: 60±2°C) were evaluated during the storage period (0, 20 and 40 days). The peroxide value (PV), free fatty acids (FFA), and antioxidant activity of the ghee samples were analyzed and compared with control sample (without additives). The PV and FFA content were significantly higher in the control sample than in the ghee samples treated with BHA, LPE, and MPE at all storage temperatures and during the storage period. All treatments led to a reduction in the PV and FFA content, but LPE had the most significant effect, followed by BHA and MPE, respectively. Antioxidant activity was evaluated by the 3-ethyl benzthiazoline-6-sulphonic acid (ABTS) assay; LPE had the highest antioxidant activity, followed by MPE. Compared to the control sample: BHA, LPE and MPE led to a higher reduction in the PV and FFA content of ghee samples at all storage temperatures and periods owing to their antioxidant activities. Results of incorporated samples showed that using LPE (0.1%) prevented the development of PV and FFA content of ghee samples less than using BHA (0.2%). The present study suggests that LPE (0.1%) could be used as a good natural antioxidant preservative to reduce oxidative deterioration of ghee and fat-rich products.

Green synthesis of silver nanoparticles by waste of Murcott Mandarin peel as a sustainable approach for efficient heavy metal removal from metal industrial wastewater

This study introduces a sustainable and environmentally friendly method for synthesizing silver nanoparticles (Ag-NPs) using waste from Murcott Mandarin peel (Citrus reticulata Blanco × C. sinensis (L.) Obs.). By repurposing agricultural waste as a precursor for nanoparticle synthesis, the research not only reduces waste but also aligns with green chemistry principles. The synthesis process involved extracting bioactive compounds from Murcott Mandarin peel, which acted as both reducing and stabilizing agents during nanoparticle formation. Characterization techniques, including UV–Vis spectroscopy and X-ray diffraction (XRD), confirmed the successful formation of silver nanoparticles. These nanoparticles demonstrated exceptional efficiency in removing heavy metals from metal industrial wastewater, particularly lead ions. Batch experiments revealed significant adsorption capabilities, with lead ions being uptake by silver nanoparticles at a rate of 42.7 mg/g under optimal conditions of pH 5.5 and 60 min of stirring. Additionally, Murcott Mandarin Solid Residue (MM-SR) obtained from the filtration process during Ag-NP synthesis exhibited promising lead ion uptake, reaching 6.6 mg/g under the same optimal conditions. The eco-friendly synthesis route and the efficient heavy metal removal capabilities of silver nanoparticles underscore the potential of utilizing agricultural waste in nanomaterial synthesis for wastewater treatment. This approach not only tackles waste disposal challenges but also generates value-added materials with practical applications in environmental management. Overall, the study emphasizes the importance of exploring innovative and sustainable pathways for nanoparticle synthesis, highlighting the promising role of silver nanoparticles synthesized from Murcott Mandarin peel waste in cost-effective and environmentally benign strategies for heavy metal removal in metal industrial wastewater treatment.

Narirutin-Rich Celluclast Extract from Mandarin (Citrus unshiu) Peel Alleviates High-Fat Diet-Induced Obesity and Promotes Energy Metabolism in C57BL/6 Mice.

Mandarin peel, a main by-product from the processing of citrus juice, has been highlighted for its various bioactivities and functional ingredients. Our previous study proved the inhibitory effects of Celluclast extract from mandarin peel (MPCE) on lipid accumulation and differentiation in 3T3-L1 adipocytes. Therefore, the current study aimed to evaluate the anti-obesity effect of MPCE in high-fat diet (HFD)-induced obese mice. The high-performance liquid chromatography (HPLC) analysis exhibited that narirutin and hesperidin are the main active components of MPCE. Our current results showed that MPCE supplementation decreased adiposity by reducing body and organ weights in HFD-induced obese mice. MPCE also reduced triglyceride (TG), alanine transaminase (ALT), aspartate transaminase (AST), and leptin contents in the serum of HFD-fed mice. Moreover, MPCE significantly inhibited hepatic lipid accumulation by regulating the expression levels of proteins associated with lipid metabolism, including sterol regulatory element-binding protein (SREBP1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC). Furthermore, MPCE administration significantly inhibited both adipogenesis and lipogenesis, with modulation of energy metabolism by activating 5' adenosine monophosphate-activated protein kinase (AMPK) and lipolytic enzymes such as hormone-sensitive lipase (HSL) in the white adipose tissue (WAT). Altogether, our findings indicate that MPCE improves HFD-induced obesity and can be used as a curative agent in pharmaceuticals and nutraceuticals to alleviate obesity and related disorders.

Comparative Evaluation of Secondary Metabolite Chemodiversity of Citrus Genebank Collection in Greece: Can the Peel be More than Waste?

Citrus fruits are among the most economically important crops in the world. In the global market, the Citrus peel is often considered a byproduct but substitutes an important phenotypic characteristic of the fruit and a valuable source of essential oils, flavonoids, carotenoids, and phenolic acids with variable concentrations. The Mediterranean basin is a particularly dense area of autochthonous genotypes of Citrus that are known for being a source of healthy foods, which can be repertoires of valuable genes for molecular breeding with the focus on plant resistance and quality improvement. The scope of this study was to characterize and compare the main phenotypic parameters (i.e., peel thickness, fruit volume, and area) and levels of bioactive compounds in the peel of fruits from the local germplasm of Citrus in Greece, to assess their chemodiversity regarding their polyphenolic, volatile, and carotenoid profiles. A targeted liquid chromatographic approach revealed hesperidin, tangeretin, narirutin, eriocitrin, and quercetin glycosides as the major polyphenolic compounds identified in orange, lemon, and mandarin peels. The content of tangeretin and narirutin followed the tendency mandarin > orange > lemon. Eriocitrin was a predominant metabolite of lemon peel, following its identification in lower amounts in mandarin and at least in the orange peel. For these citrus-specific metabolites, high intra- but also interspecies chemodiversity was monitored. Significant diversity was found in the essential oil content, which varied between 1.2 and 3% in orange, 0.2 and 1.4% in mandarin, and 0.9 and 1.9% in lemon peel. Limonene was the predominant compound in all Citrus species peel essential oils, ranging between 88 and 93% among the orange, 64 and 93% in mandarin, and 55 and 63% in lemon cultivars. Carotenoid analysis revealed different compositions among the Citrus species and accessions studied, with β-cryptoxanthin being the most predominant metabolite. This large-scale metabolic investigation will enhance the knowledge of Citrus peel secondary metabolite chemodiversity supported by the ample availability of Citrus genetic resources to further expand their exploitation in future breeding programs and potential applications in the global functional food and pharmaceutical industries.

Preparation, Characterization and Application of Active Food Packaging Films Based on Sodium Alginate and Twelve Varieties of Mandarin Peel Powder.

The industrial processing of mandarin fruits yields a large amount of peel waste, resulting in economic losses and environmental pollution. The peels of mandarin fruits are a good source of biomass and active substances that can be used to produce food packaging systems. In this study, active food packaging films were prepared based on sodium alginate and twelve varieties of mandarin peel powder. The structures, properties, and corn oil packaging performance of the films were compared. Results showed that the twelve varieties of mandarin peel powder differed in pectin, lipid, protein, crude fiber, and total phenol contents. The prepared films all exhibited a yellow color, 117.73-152.45 μm thickness, 16.39-23.62% moisture content, 26.03-90.75° water contact angle, 5.38-8.31 × 10-11 g m-1 s-1 Pa-1 water vapor permeability, 5.26-12.91 × 10-20 m2 s-1 Pa-1 oxygen permeability, 4.87-7.90 MPa tensile strength, and 13.37-24.62% elongation at break. Notably, the films containing mandarin peel powder with high pectin and lipid contents showed high moisture/oxygen barrier ability and mechanical properties. The films containing mandarin peel powder with high total phenol content exhibited high antioxidant- and antimicrobial-releasing abilities and good performance in delaying corn oil oxidation. Overall, the results suggested that the films have good application potential in active food packaging.

Thermochemical treatment of mixed mandarin peel and algae via microwave and H3PO4 activation: process optimization and adsorption mechanism for methylene blue dye

Thermochemical treatment of mixed mandarin peel and algae via microwave and H3PO4 activation: process optimization and adsorption mechanism for methylene blue dye

The Effects of Microwave and Oven Drying on Bioactive Compounds Individual Phenolic Constituents and the Fatty Acid Profiles of Bitter Orange, Mandarin and Grapefruit Peel and Oils

The Effects of Microwave and Oven Drying on Bioactive Compounds Individual Phenolic Constituents and the Fatty Acid Profiles of Bitter Orange, Mandarin and Grapefruit Peel and Oils

Laboratory evaluation of a bio-insecticide candidate from tangerine peel extracts against Trialeurodes vaporariorum (Homoptera: Aleyrodidae).

The excessive use of synthetic insecticides in modern agriculture has led to environmental contamination and the development of insect resistance. Also, the prolonged use of chemical insecticides in producing flowers and tomatoes in greenhouses has caused health problems for workers and their offspring. In this study, we analyzed the efficacy of mandarin peel (Citrus reticulata L.) essential oil (EO) as a natural insecticide against greenhouse whitefly (Trieurodes vaporariorum W., Homoptera: Aleyrodidae), a common pest in greenhouse production of different crops. Petroleum ether (PET) and n-hexane (HEX) were used as solvents to extract essential oil (EO) from tangerine peels. The yield of EO was 1.59% and 2.00% (m/m) for PET and HEX, respectively. Additionally, the insect-killing power of EO was tested by checking how many greenhouse whiteflies died at different times. The results showed that PET and HEX extracts of tangerine EO effectively controlled greenhouse whiteflies. Furthermore, with both solvents, a 12.5% (v/v) application was as practical as the commercial insecticide imidacloprid. Further characterization tests with the polarimeter, FTIR, HPLC-RP, and GC-MS showed that the essential oil (EO) contained about 41% (v/v) of d-limonene and that this compound may be responsible for the observed insecticidal properties. Therefore, tangerine peel essential oil is an excellent botanical insecticide candidate for controlling greenhouse whiteflies.

Egyptian Citrus Essential Oils Recovered from Lemon, Orange, and Mandarin Peels: Phytochemical and Biological Value

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.

Effect of oil phase type and lutein loading on emulsifying properties and in vitro digestion of mandarin peel pectin emulsions

Oil phases with different chain lengths and saturations were used to make mandarin peel pectin (MPP) emulsions with and without lutein loading. The outcomes demonstrated that the emulsifying, digesting characteristics and lutein bioaccessibility of MPP emulsion were related to the addition of lutein and also oil phase species. After lutein addition, the apparent viscosity of MPP emulsions and interfacial tension were dramatically decreased. MPP emulsions made from medium-chain triglyceride (MCT) oil displayed higher absolute zeta potential, free fatty acid release, and lutein bioaccessibility, while those made from long-chain triglyceride (LCT) (palm oil, corn oil, and olive oil) had higher volume average particle size and interfacial tension. The findings offered a theoretical foundation for effective delivery and release of lutein by pectin emulsion.

Micronutrient and antinutrient content of semi-processed fruit peels: Towards boosting immunity.

Fruits are excellent sources of micronutrients; hence, their consumption is highly recommended. However, fruit peels, often discarded, despite some being edible have been reported to contain essential nutrients and antioxidants, which contribute to disease prevention and well-being. This study sought to evaluate the micronutrient and antinutrient content of 10 edible fruit peels namely, orange, mango, pineapple, banana, lemon, mandarin, red apple, cucumber, guava and pawpaw peels. Laboratory analyses of the fruit peels were conducted at the University of Calabar, in a well-ventilated and temperature controlled environment to ensure accurate results. The research design was quantitative and experimental; laboratory analyses were carried out to determine the minerals, vitamins and antinutrients in fruit peels using AOAC standard methods. Data were analysed using ANOVA on SPSS version 20.0. Calcium was the most predominant of the minerals analysed, with values ranging from 33.12 ± 0.05 mg/100 g (cucumber peels) to 72.04 ± 0.08 mg/100 g (mango peels); calcium was followed by magnesium. Mandarin, banana and pineapple peels had statistically similar (p > 0.05) content of zinc (about 1.2 mg/100g), which was significantly (p < 0.05) higher than others. Mandarin peels had significantly higher content (100.48 ± 2.03 mg/100 g) of vitamin C, while cucumber peels recorded the lowest (27.50 ± 0.01 mg/100 g). The results show significant concentrations of micronutrients such as iron, selenium and vitamin K; among the antinutrients, hydrogen cyanide had the highest concentrations, followed by phytate. The values were within safe limits. Therefore, the processing of fruit peels, for use as dietary additives to enrich foods and boost immunity, should be promoted. The study shows the potential of fruit peels as food additives.