Search Results (43)

The recovery of green waste and biomass presents a significant challenge in the 21st century. In this context, this study aims to valorize waste generated by the fruit juice processing industry at the N’Gaous unit (composed of the orange peel, fibers, pulp, and seeds) as an adsorbent to eliminate an anionic dye and to enhance its adsorption capacity through thermal activation at 200 °C and 400 °C. The aim is also to determine the parameters for the adsorption process including contact time (0–120 min), solution pH (2–10), initial dye concentration (50–700 mg/L), and adsorbent dosage (0.5–10 g/L). The adsorption tests showed that waste activated at 400 °C (AR400) demonstrated a higher efficiency for removing indigo carmine (IC) from an aqueous solution than waste activated at 200 °C (AR200) and unactivated waste (R). The experimental maximum adsorption capacities for IC were 70 mg/g for unactivated waste, 500 mg/g for waste activated at 200 °C, and 680 mg/g for waste activated at 400 °C. These tests were conducted under conditions of pH 2, an equilibrium time of 50 min, and an adsorbent concentration of 1 g/L. The analysis of the kinetic data revealed that the pseudo-second-order model provides the best fit for the experimental results, indicating that this mechanism predominates in the sorption of the pollutant onto the three adsorbents. In terms of adsorption isotherms, the Freundlich model was found to be the most appropriate for describing the adsorption of dye molecules on the R, AR200, and AR400 supports, owing to its high correlation coefficient. Before adsorption tests, the powder R, AR200 and AR400 were characterized by various analyses, including Fourier transform infrared (FTIR), pH zero charge points and laser granularity for structural evaluation. According to the results of these analyses, the specific surface area (SSA) of the prepared material increases with the increase in the activation temperature, which expresses the increase in the adsorption of material activated at 400 °C, compared with materials activated at 200 °C and the raw material. Full article

The valorization of citrus peel byproducts presents a sustainable and innovative approach to reducing food waste while improving the nutritional content of fruit-based products. Citrus peels, a significant byproduct of the fruit juice industry, are abundant in bioactive compounds with recognized health benefits and functional properties, making them particularly suitable for jam production. The global citrus industry generates substantial amounts of waste, with peels accounting for approximately 50% of the total fruit mass. Conventional disposal methods often result in environmental concerns and the underutilization of valuable bioresources. This study aims to investigate the potential of incorporating citrus peel into jam formulations as a means of enhancing their nutritional and functional properties. Jams were prepared using a traditional processing technique (TP) incorporating citrus peel. The experimental jam variants included pomelo peel jam (PPJ), lime peel jam (LiPJ), lemon peel jam (LePJ), clementine peel jam (CPJ), orange peel jam (OPJ), and grapefruit peel jam (GPJ). All jam samples were subjected to comprehensive analyses, including assessments of chemical composition, total soluble solids (TSSs), titrable acidity (g/100 g acid citric), macro- and microelement contents, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity using the FRAP assay. The study revealed high levels of biologically active compounds, such aspolyphenols, flavonoids, and vitamin C, in the jams, highlighting their antioxidant properties and potential health benefits. Among the jams, lemon peel jam (LePJ) exhibited the highest antioxidant activity and polyphenol content, making it a superior choice in terms of functional benefits. In terms of sensory analysis, orange peel jam (OPJ) was the most favored by consumers, demonstrating its high acceptability and potential for market success. Full article

Brazil is a global leader in the orange industry, producing approximately one-fourth of the world’s oranges and generating over 50% of the associated waste. These by-products are rich in bioactive compounds; however, their improper disposal poses environmental risks. This study employs an eco-friendly approach—microwave-assisted extraction—to recover valuable compounds from orange juice production waste. The extracted compounds were analyzed using nuclear magnetic resonance (NMR) and gas chromatography–mass spectrometry (GC–MS). Key bioactives, including D-limonene, valencene, hesperidin, and carbohydrates, were successfully identified. NMR effectively traces and semi-quantifies these compounds, while microwave-assisted extraction enables the sustainable recovery of high-purity hesperidin, confirmed by NMR (87.66%) and HPLC (84.30%) analyses. Full article

This work aimed to propose the reuse of processing waste from the Sicilian almond (Prunus amygdalus Batsch.) cultivar Tuono for the formulation of a new functional baked product (muffin) that is gluten- and lactose-free. Muffins were prepared using orange juice, rice flour, extra virgin olive oil, and enriched almond skin (3% and 6% w/w). The chemical-physical parameters, total phenols, and flavonoids (TPC and TFC), as well as the biological properties of the ingredients and muffins, were evaluated. Sensory analyses were also conducted. DPPH, ABTS, β-carotene bleaching, and FRAP tests were applied to measure the antioxidant potential. Muffin extracts were also tested against α-amylase and α-glucosidase enzymes. Muffins enriched with 6% almond skin (M6) showed the highest TPC and TFC with values of 26.96 mg gallic acid equivalent (GAE)/g and 24.12 mg quercetin equivalent (QE)/g, respectively. M6 exerted a promising antioxidant activity as an inhibitor of lipid peroxidation, with an IC₅₀ of 15.44 μg/mL at 30 min incubation. Moreover, muffin M6 showed a promising α-glucosidase inhibitory effect (IC₅₀ of 51.82 μg/mL). Based on the obtained results and supported by sensory analysis, muffins enriched with almond skin should be proposed as a promising example of upcycling for the development of a new functional bakery product. Full article

Citrus fruits are widely consumed worldwide; however, one of their primary uses is juice production, resulting in over 40 million tons of agro-industrial waste. Citrus peel is the main agro-industrial by-product in citrus production. In recent years, secondary metabolites of interest, mainly polyphenols such as hesperidin, have been identified in citrus peels. Currently, green alternatives like natural deep eutectic solvents (NADES) based on choline chloride and glucose (Glu), combined with ultrasound-assisted extraction, are studied to obtain polyphenol-rich extracts with potential health applications. This study aims to evaluate the effect of: (1) molar ratios (MR) of 1:0.5, 1:1 or 1:2 mol/mol of choline chloride (ChCl):glucose (Glu); (2) the percentage of added water (WA: 50, 60 or 70%) to NADES; and (3) different citrus peels of Citrus aurantium (bitter orange), Citrus sinensis (sweet orange), and Citrus limon (lemon) used for extraction, on polyphenol profiles, total polyphenol content (TPC), and antioxidant capacity (Ax) of the extracts. The extracts were analyzed using ultra-performance liquid chromatography (UPLC) and evaluated using the Folin–Ciocalteu method for TPC and DPPH assay for quantifying AC. A factorial experimental design 3³ was implemented. The extract obtained with an MR of 1:1 (ChCl:Glu) from Citrus aurantium peel exhibited the highest concentration of hesperidin (2003.37 ± 10.91 mg/100 g dry mass), whereas an MR of 1:2 (ChCl:Glu) exhibited the highest concentration of neohesperidin (1045.94 ± 1.27 mg/100 g dry mass), both using 60% WA. This extract also showed the highest antioxidant capacity, achieving 100% inhibition. On the other hand, the highest concentration of total phenolic content (TPC) (96.23 ± 0.83 mg GAE/100 g dry mass) was obtained using C. aurantium peel with an MR of 1:0.5 (ChCl:Glu) and 60% WA. The extracts also presented high concentrations of rutin and catechin. These findings highlight the potential of revalorizing citrus peels, particularly Citrus aurantium, and their extracts obtained with NADES for possible health applications. Full article

Citrus waste has been used as a source of bioplastics for research in different ways. Because the juice industry produces significant amounts of residue each year, it would be advantageous to use the byproducts in the creation of new materials. Researchers have long explored eco-friendly methods to convert citrus and other organic waste into polymers for producing biodegradable films. The goal of this study is to create biofilms from orange waste (OW) and ginger waste (GW) using an ultrafine grinder and study the films’ properties. Since pectin has the ability to gel, and because cellulosic fibers are strong, citrus waste has been studied for its potential to produce biofilms. After being washed, dried, and milled, orange and ginger waste was shaped into films using a casting process. Tensile testing was used to determine the mechanical properties of biofilms, while dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) were used to determine their thermal properties. As the number of grinding cycles increased, the suspension’s viscosity increased from 29 mPa.s to 57 mPa.s for OW and from 217 mPa.s to 376 mPa.s for GW, while the particle size in the suspension significantly decreased. For OW and GW films, the highest tensile strength was 17 MPa and 15 MPa, respectively. The maximum strain obtained among all films was 4.8%. All the tested films were stable up to 150 °C, and maximum degradation occured after 300 °C. Full article

A byproduct from orange juice processing known as pastazzo represents a significant organic waste stream. Rich in essential oils and known for its inhibitory effect on plant germination, pastazzo could serve as a valuable input for agricultural purposes. This study assesses the effects of a 40% w/v orange pastazzo water extract (OPWE) produced by hydrodynamic cavitation on the germination of two species, one of economic interest (Lactuca sativa L.) and one common weed (Chenopodium album L.). Three dilutions of OPWE in water (25%; 50%; 75%) were compared to a control treatment in four experiments, using (i) seeds in Petri dishes; (ii) seeds in commercial substrate; (iii) C. album seeds and transplanted L. sativa in commercial substrate; and (iv) other weeds in an open-field plantation of L. sativa. Highly rich in limonene, OPWE applied at higher concentrations in Petri dishes caused the effective inhibition of germination in C. album and a germination delay in L. sativa. Similar results were observed in the germination of the two species in commercial substrate, with none of the dilutions affecting L. sativa biomass. In the field experiment, despite a relatively low number of weeds in the control treatment, higher OPWE concentrations reduced the number of grasses and forbs, largely confirming the inhibitory effects. We conclude that OPWE produced with hydrodynamic cavitation, an efficient and affordable method of extraction, represents an effective crop treatment due to the species-specific effects of its constituent limonene on plant germination. Further tests are essential to understand the extent to which OPWE interacts with other species and types of substrate. Full article

Few valorization pathways have been implemented as alternatives to reduce the orange peel waste (OPW) disposal in landfills. OPW can be a source of income or economic savings in juice production factories since this waste is a potential source of value-added products (e.g., bioactive compounds) and energy vectors (e.g., biogas). Valorization alternatives should be based on (i) orange peel chemical composition, (ii) market analysis, and (iii) availability. Nevertheless, few literature papers have highlighted the chemical composition change caused by the different juice production schemes as a potential opportunity to obtain different value-added products and biorefinery schemes. Thus, the aims of this review paper are related to (i) reviewing different orange fruit processing pathways, (ii) analyzing several OPW chemical compositions reported in the open literature, (iii) providing a summary of OPW extraction pathways for bioactive compounds production, and (iv) evaluating the effect of applying different extraction methods on bioactive compound extraction performance. This review includes a description of the OPW matrix, market insights, packaging, physicochemical characterization, processing technologies, and suggested biorefinery approaches. Finally, different extraction methods for obtaining bioactive compounds from OPW are compared. As a result, the supercritical fluid extraction process has the highest extraction performance and selectivity since this method extracted a high amount of hesperidin (8.18 g/kg OPW db.). In conclusion, OPW is a source of bioactive compounds and valuable products that can be introduced in juice-producing factories to increase product portfolio or economic savings by changing the energy matrix. Full article

Batch experiments were conducted to test orange waste (OW), an agricultural solid waste byproduct from the orange juice manufacturing industry, as adsorbent for binary solutions of Cd²⁺-Cr³⁺ and Zn²⁺-Cr³⁺. Fourier transform infrared spectroscopy (FTIR) and the point of zero charge (pH_pzc) were used to identify the functional groups on the OW surface involved in biosorption. The biosorption equilibrium data for both binary-metal solutions were obtained and fitted to various isotherm models. The extended Sips and the non-modified Redlich-Peterson isotherm models gave the best fit for the experimental data. According to the extended Sips model, the maximum biosorption capacity of OW was 0.573 mmol·g⁻¹ for Cd²⁺, 0.453 mmol·g⁻¹ for Zn²⁺, and 1.96 mmol·g⁻¹ for Cr³⁺. The sorption capacity dropped to 0.061 mmol·g⁻¹ for Cd²⁺ and to 0.101 mmol·g¹ for Zn²⁺ in their binary systems with Cr³⁺ for the higher initial metal concentrations in the solution. However, the maximum sorption capacity of chromium was only slightly affected by the presence of Cd²⁺ or Zn²⁺. For both binary systems, the presence of a second metal ion in the solution always conduces to a reduction in the sorption of the other metal in the solution. The presence of Cr³⁺ decreased the sorption of Cd²⁺ and Zn²⁺ more than vice versa. Conclusively, effective removal of Cr³⁺ ions from an aqueous solution can still be achieved in the presence of Cd²⁺ or Zn²⁺. Full article

The development of efficient energy storage systems is critical in the transition towards sustainable energy solutions. In this context, the present work investigates the viability of using orange juice, as a promising and sustainable precursor, for the synthesis of activated carbon electrodes for supercapacitor technologies. Through the carbonization-activation process and controlling the preparation parameters (KOH ratio and activation time), we have tailored the specific surface area (SSA) and pore size distribution (PSD) of the resulting carbon materials—crucial parameters that support supercapacitive performance. Several spectroscopic, morphological, and electrochemical techniques are used to characterize the obtained carbon materials. In particular, our optimization efforts revealed that a 5:1 KOH ratio with an activation time up to 120 min produced the highest SSA of about 2203 m²/g. Employing these optimal conditions, we fabricated symmetric coin cell supercapacitors using Na₂SO₄ as the electrolyte, which exhibited interesting specific capacitance (~56 F/g). Durability testing over 5000 cycles sustained the durability of the as-made activated carbon electrodes, suggesting an excellent retention of specific capacitance. This study not only advances the field of energy storage by introducing a renewable material for electrode fabrication but also contributes to the broader goal of waste reduction through the repurposing of food byproducts. Full article

Orange-juice production represents a significant, world-leading economic sector in Brazil. Orange processing residues, however, correspond to 50% to 60% of the in natura fruit mass. Despite the high amount of generated waste, which is disposed of in landfills or used as raw material to produce low-value animal feed, studies on the use of this waste are still developing in Brazil. However, orange peels contain compounds that can be precursors to higher value-added products in different sectors. Therefore, this study presents a conceptual proposal for a biorefinery integrated into the orange-juice-production route to assess integrated processes’ technical, environmental, and economic performance to convert waste into chemicals, fuels, and energy. A stationary process simulation model was developed to analyze the manufacturing of four products, namely, D-limonene, pectin, biomethane, and electricity, comparing the results to the conventional feed production route according to generated revenue and environmental impacts. The results indicate that pectin production is the highest financial-return route, presenting the most significant environmental impact, whereas D-limonene production is more attractive, generating the second-highest revenue with the lowest associated environmental impacts. Full article

Pectinases are enzymes used in several industrial processes. Seven agroindustrial wastes—jackfruit seed meal (Artocarpus heterophyllus), cocoa seed peel (Theobroma cacao), cocoa husks (Theobroma cacao), passion fruit husks (Passiflora edulis), mangosteen husks (Garcinia mangostana), malt residue (Hordeum vulgare) and the peach palm waste (Bactris gasipaes Kunth.)—were evaluated to produce a crude extract containing pectinase activity by Penicillium rolfsii CCMB 714. The jackfruit seed meal was chosen as the best substrate for solid-state fermentation, which was optimized with 4 mL of water as a wetting agent for 2 days at 35 °C and with a 0.5% nitrogen source, whereby the pectinase production increased by 44% (362.09 U/g). The obtained crude extract was characterized and applied to wastes saccharification and orange juice clarification. The pectinase showed better activity at a pH of 3.0 to 5.0 and 55 °C, it stably maintained over 80% of activity at 30–50 °C for up to 60 min and 1 mM CuSO₄ increased the pectinase activity by 17%. The saccharification of agroindustrial wastes (cocoa husks, mangosteen husks and passion fruit husks) resulted in 126.55 µmol/mL of reducing sugars from passion fruit husks, which represents an increase of 126% after optimization (45 °C for 22 h). For the clarification of orange juice, it was possible to reduce the absorbance of the juice by 55%. These results elucidate the potential of the low-cost pectinase solution from P. rolfsii CCMB 714 cultivated in jackfruit seed meal for both the enzymatic pretreatment of plant biomass and the application in beverage industries. Full article

The bioconversion of agri-food waste into high-value products is gaining growing interest worldwide. Orange peel waste (OPW) is the main by-product of orange juice production and contains high levels of moisture and carbohydrates. In this study, the orange waste extract (OWE) obtained through acid hydrolysis of OPW was used as a substrate in the cultivation of the marine microalgae Nannochloropsis oculata. Photoheterotrophic (PH) and Photoautotrophic (PA) cultivations were performed in OWE medium and f/2 medium (obtained by supplementing OWE with macro- and micronutrients of f/2 medium), respectively, for 14 days. The biomass yields in PA and PH cultures were 390 mg L⁻¹ and 450 mg L⁻¹, while oil yields were 15% and 28%, respectively. The fatty acid (FA) profiles of PA cultures were mostly represented by saturated (43%) and monounsaturated (46%) FAs, whereas polyunsaturated FAs accounted for about 10% of the FAs. In PH cultures, FA profiles changed remarkably, with a strong increase in monounsaturated FAs (77.49%) and reduced levels of saturated (19.79%) and polyunsaturated (2.72%) FAs. Lipids obtained from PH cultures were simultaneously extracted and converted into glycerol-free biodiesel using an innovative microwave-assisted one-pot tandem protocol. FA methyl esters were then analyzed, and the absence of glycerol was confirmed. The FA profile was highly suitable for biodiesel production and the microwave-assisted one-pot tandem protocol was more effective than traditional extraction techniques. In conclusion, N. oculata used OWE photoheterotrophically, resulting in increased biomass and oil yield. Additionally, a more efficient procedure for simultaneous oil extraction and conversion into glycerol-free biodiesel is proposed. Full article

More than 58 million metric tonnes of oranges were produced in 2021, and the peels, which account for around one-fifth of the fruit weight, are often discarded as waste in the orange juice industry. Orange pomace and peels as wastes are used as a sustainable raw material to make valuable products for nutraceuticals. The orange peels and pomace contain pectin, phenolics, and limonene, which have been linked to various health benefits. Various green extraction methods, including supercritical carbon dioxide (ScCO₂) extraction, subcritical water extraction (SWE), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE), are applied to valorize the orange peels and pomace. Therefore, this short review will give insight into the valorization of orange peels/pomace extraction using different extraction methods for health and wellness. This review extracts information from articles written in English and published from 2004 to 2022. The review also discusses orange production, bioactive compounds in orange peels/pomaces, green extractions, and potential uses in the food industry. Based on this review, the valorization of orange peels and pomaces can be carried out using green extraction methods with high quantities and qualities of extracts. Therefore, the extract can be used for health and wellness products. Full article

The main aim of this study was to evaluate the effect of the addition of selected industrial food wastes on the fate of micro- and macro-elements within an anaerobic digestion process (AD), as well as define the relationship between their content and AD efficiency. Orange peels, (OP), orange pulp (PL) and brewery spent grain (BSG) were used as co-substrates, while municipal sewage sludge (SS) was applied as the main component. The introduction of co-substrates resulted in improvements in feedstock composition in terms of macro-elements, with a simultaneous decrease in the content of HMs (heavy metals). Such beneficial effects led to enhanced methane production, and improved process performance at the highest doses of PL and BSG. In turn, reduced biogas and methane production was found in the three-component digestion mixtures in the presence of OP and BSG; therein, the highest accumulation of most HMs within the process was also revealed. Considering the agricultural application of all digestates, exceedances for Cu, Zn and Hg were recorded, thereby excluding their further use for that purpose. Full article