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• 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]

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]

• 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]

The paradigm shifts from discarding horticulture byproducts to exploiting them for their bioactive potential has encouraged research on non-conventional extraction techniques such as extraction using microwave, ultrasound, high-pressure, etc. Kinnow peels, a primary residue of kinnow processing industry, are profuse with polysaccharides, such as dietary fiber which can be isolated and used as a functional ingredient in fortified/enriched foods. In the present study, ultrasound-assisted extraction (UAE) and ultrasound-assisted-enzymatic extraction (UAEE) have been optimized to maximize dietary fiber yield from kinnow peel waste. Total dietary fiber (TDF) of 52.042 ± 0.862% was observed using UAE at 38% amplitude, liquid to solid ratio (LSR) of 40 mL/g, at 44 °C, after sonication time of 13 min, which increased to 60.974 ± 0.827% upon sequential enzymatic treatment. The WHC, OHC, and GAC of extracted dietary fiber ranged between 8.17 and 9.24 ± 0.11 g/g, 2.96–4.68 ± 0.09 g/g, and 1.56–2.28 ± 0.04 mmol/g. The physicochemical characterization of dietary fiber using analytical instruments and its functional properties such as oil/water holding, and glucose adsorption capacities proved that kinnow peels dietary fiber can be used to develop fiber-enriched products. The extracted fiber has been used to develop cookies which showed good nutritional, sensory, and textural properties with an overall acceptability of 7.15–7.84. This research will be helpful in scale-up studies on the valorization of different citrus peels through an extraction approach. [Display omitted] [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize a polysaccharide found in citrus peels with an anti-metastatic property. CPE-II was purified by the pectinase digestion of citrus peels. During in vivo lung metastasis of Colon26-M3.1, administration of 10 μg of CPE-II per mouse showed 81.3% inhibition of metastasis. CPE-II consists of 15 different monosaccharides and 22 different glycosyl linkages, characteristic of rhamnogalacturonan II (RG-II). The primary structure was elucidated based on sugar composition, methylation analysis, oligosaccharide analysis, and sequencing using GC, GC–MS, LC–MS, and ESI–MS/MS analyses. Sequential degradation using partial acid hydrolysis indicated that CPE-II contained Rha p -(1 → 5)-Kdo, Ara f -(1 → 5)-Dha, an AceA-containing nonasaccharide, and an uronic acid-rich oligosaccharide in addition to an α-(1 → 4)-galacturono-oligosaccharide main chain. The molecular weight of CPE-II was observed to decrease from 9 to 5 kDa at a pH value of <2.0, as observed by HPSEC. Thus, we propose that the anti-metastatic CPE-II is primarily present as an RG-II dimer. [ABSTRACT FROM AUTHOR]

Renewable sources of hydrogen are of major interest in the context of energy production through fuel cells. The technical feasibility of CHP system composed by orange peels steam/air gasification unit coupled with a solid oxide fuel cell (SOFC) was investigated in this study. To this purpose, a zero-dimensional process simulation model of the CHP system using Aspen Plus was developed. Mathematical model was experimentally validated in a lab scale apparatus. Moreover, optimal operative conditions and integration options were investigated, as well as the system maximum theoretical overall efficiency. Results showed that in order to obtain 120 kW of DC power from the specific SOFC, 65 kg/h of biomass with 20% of moisture and 173 kg/h of raw biomass with 70% of water needed to be fed in the CHP system. It was theoretically proved that 120 kW of DC power and 135 kW of heat could be produced from SOFC unit at the selected operative conditions, with a net CHP maximum efficiency equal to 74%. [ABSTRACT FROM AUTHOR]

The thermal and ex-situ catalytic pyrolysis of different citrus peels, Citrus paradisi peel, Citrus sinensis peel, Citrus unshiu peel, and Citrus limon peel, were studied by thermogravimetric, evolved gas analysis–mass spectrometry and tandem micro-reactor–gas chromatograph/mass spectrometry analyses. Kinetic analysis revealed more complicated reaction steps and a wider range of activation energies of citrus peels than those of wood powder due to the presence of pectin in the citrus peels. Large amounts of methanol formation from each citrus peel were also recorded by evolved gas analysis–mass spectrometry and fast pyrolysis–gas chromatograph/mass spectrometry analyses at the main decomposition temperature of pectin, between 150 and 250 °C. Mesoporous MFI was found to be a more effective catalyst for the production of mono aromatic compounds (benzene, toluene, ethylbenzene, and xylene; 3.06–4.17 C%) and light olefins (ethene, propene, butene, and butadiene; 8.13–9.13 C%) than Al-MCM-41 (mono aromatic compounds 0.67–0.93 C% and light olefins 3.61–4.58 C%) because of its higher catalytic activity in deoxygenation and aromatization due to the stronger acidity of mesoporous MFI. The yield of mono aromatic compounds over mesoporous MFI was highest from C. paradisi peel (4.17 C%), followed in order by C. sinensis peel (3.83 C%), C. unshiu peel (3.61 C%), and C. limon peel (3.06 C%), due mainly to the different contents and properties of pectin in each citrus peel. The higher activities of mesoporous MFI than Al-MCM-41 were also maintained during the 7 times sequential catalytic pyrolysis of C. paradisi peel, demonstrating the stability of mesoporous MFI catalyst. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this work is to investigate the effect of microwave dehydration (100, 180, 300, 450 and 600W) on the physico-chemical (shrinkage, total phenols and color) and technological properties (water and oil retention capacities) and the drying behaviour of three citrus peel cultivars (thompson navel, mandarin and lemon). The fresh citrus peel of thompson navel, mandarin and lemon are characterized by high moisture (3.140±0.159; 3.798±0.070 and 3.010±0.143kg water/kg db) and fiber (41.644±1.891; 27.894±2.358 and 39.135±1.250g/100g db) contents. As excepected, whatever the citrus cultivar, the microwave power level has a significant effect on drying time of the citrus peel (drying time ranges from 51.5±2.828min to 79±0.707min at 100W and from 8.75±0.353min to 12±0.707min at 600W). Shrinkage of volume does not depend on the peel cultivar variety and on the microwave drying level but on the quantity of evaporated moisture. Microwave drying induces a significant increase of the water retention capacities of the three citrus peels. The microwave powers lower than 450W were in favour of the best water retention capacities. Microwave drying decreases significantly the oil retention capacities of all citrus peels and the total phenolic contents of mandarin and lemon peels. The maximal peel phenolic contents were preserved for drying microwave power higher than 450W. Also, microwave drying does not have a significant effect on color parameter (L*, a*, b*) of thompson and mandarin peels howerver it induces a significant decrease of the parameter b* and an increase of the global color difference, ΔE, of lemon peels. [Copyright &y& Elsevier]

Abstract: The use of phytogenic bioactive compounds to control poultry helminthes is increasing in different production systems. In vitro and in vivo anthelmintic activity of citrus peels against Ascaridia galli was investigated. Ethanolic extracts of three citrus peels species were suspended in 0.5% dimethyl sulfoxide (DMSO) to form an experimental composition (EC). EC was mainly composed of Limonene (96%), followed by β-Pinene (1.5%), α-Pinene (0.5%), and Sabinene (0.3%). For in vitro investigation, adult A. galli worms (n =225) were collected from naturally infected chickens and distributed to 3 equal groups. Groups 1, 2, and 3 were exposed to Fenbendazole (0.5mg/ml), EC (50mg/ml), and 0.5% DMSO, respectively. For in vivo investigation, 200 Lohmann Selected Leghorns chicks were infected at 1-day old with 250 embryonated A. galli eggs. At 6 weeks of age, 150 A. galli infected birds were randomly allocated into 5 equal groups. Groups 1, 2, and 3 were treated with 300, 600, and 1200mg ECkg−1 body weight, respectively. Group 4 was treated with Fenbendazole (50mgkg−1). Group 5 was left as control. Birds were euthanized 2-weeks post-treatment, and all worms were collected from their intestines. EC possessed significant (P <0.001) in vitro anthelmintic properties on live worms. No significant (P >0.05) difference was quantified between number of motile worms exposed either to EC or Fenbendazole 7h post-exposure. A significant (P <0.0001) reduction in fecal egg count was observed 14 days post-treatment with 1200mgkg−1 EC. No significant differences were observed in worm burden of the 300mg EC-treated group compared to the controls. In contrast, the 600 and 1200mg EC-treated groups showed significant (P <0.0001) reduction in worm burden. Fenbendazole was the most effective in reducing A. galli burden (Efficacy=97%) followed by 1200mg ECkg−1 (68%), 600mg ECkg−1 (66%), and 300mg ECkg−1 (5%). It is concluded that citrus peels extracts have potential anthelmintic properties against A. galli. [Copyright &y& Elsevier]

Abstract: Citrus peel biosorbents are efficient in removing heavy metals from wastewater. Heavy metal recovery and sorbent regeneration are important for the financial competitiveness of biosorption with other processes. The desorbing agents HNO3, NaNO3, Ca(NO3)2, EDTA, S, S-EDDS, and Na-Citrate were studied at different concentrations to optimize cadmium elution from orange or grapefruit peels. In most cases, desorption was fast, being over 90% complete within 50min. However sodium nitrate and 0.001M nitric acid were less efficient. Several new models for desorption kinetics were developed. While zero-, first- and second-order kinetics are commonly applied for modeling adsorption kinetics, the present study adapts these models to describe desorption kinetics. The proposed models relate to the number of metal-filled binding sites as the rate-determining reactant concentration. A model based on first order kinetics with respect to the remaining metal bound performed best. Cd bound in subsequent adsorption after desorption was similar to the original amount bound for desorption by nitric acid, but considerably lower for calcium nitrate as the desorbent. While complexing agents were effective desorbents, their cost is higher than that of common mineral acids. Thus 0.01–0.1M acids are the most promising desorbing agents for efficient sorbent regeneration. [Copyright &y& Elsevier]

• A robust HPLC method able to simultaneously analyze 22 phenolic compounds. • Phenolic compound compositions differed significantly in citrus species. • Mandarin: the most total phenols and flavonoids; kumquat: the most phenolic acid. • Positive correlation between compound composition and antioxidant property. • Genetic background plays a role in determining citrus peel compound composition. Citrus peels have health-promoting effects and are a rich source of antioxidant substances. This study evaluated the compositions of phenolic compounds and antioxidant activities in the peels of 52 citrus varieties with consistent planting time and management. The highest levels of total phenols (72.95 ± 37.60 mg/g DW) and total flavonoids (71.43 ± 37.64 mg/g DW) were found in mandarin. The highest phenolic acid content (18.78 ± 0.38 mg/g DW), dominated by protocatechuic acid, was found in kumquat. The antioxidant potency composite index was 6.23–94.56, suggesting mandarin varieties HJ, TWPG, TTPG, AY28, BZH and TCJC had the highest antioxidant activity. Statistics analysis indicated phenolic compounds and antioxidant activity were positively correlated. Principal component analysis and hierarchical cluster analysis suggested a strong relationship between phenolic compound composition and genetic background. This study indicated significant differences in the biological properties of various types of citrus peels; which are valuable for future utilization and research of citrus peels. [ABSTRACT FROM AUTHOR]

Abstract: Biosorption by materials such as citrus peels could be a cost effective technique for removing toxic heavy metals from wastewater. Orange peels, lemon peels and lemon-based protonated pectin peels (PPP) had Langmuir sorption capacities of 0.7–1.2mequiv./g (39–67mg/g) of Cd per biosorbent dry weight. A potentiometric titration was interpreted using a continuous pK a spectrum approach. It revealed four acidic sites with pK a values of 3.8, 6.4, 8.4 and 10.7, and a total site quantity of 1.14mequiv./g. Sorption isotherms of untreated citrus peels showed an unusual shape with two plateau values. Protonated pectin peels on the other hand showed a typical Langmuir behavior with a higher sorption capacity than untreated peels. At lower pH, metal binding was reduced due to increased competition by protons. This was modeled using pH-sensitive isotherm equations. It was not necessary to assume four binding sites; using one site with pK a 3.8 and a quantity of 1.14mequiv./g was sufficient. It was possible to accurately predict metal uptake at one pH using the metal binding constant determined at a different pH. A 1:1 stoichiometry model fit the sorption isotherms shape better than a 1:2 stoichiometry. For constant pH, the 1:1 stoichiometry reduces to the Langmuir model. [Copyright &y& Elsevier]

Abstract: Biosorption can be used as a cost effective and efficient technique for the removal of toxic heavy metals from wastewater. Waste materials from industries such as food processing and agriculture may act as biosorbents. This study investigates the removal of cadmium by fruit wastes (derived from several citrus fruits, apples and grapes). Citrus peels were identified as the most promising biosorbent due to high metal uptake in conjunction with physical stability. Uptake was rapid with equilibrium reached after 30–80min depending on the particle size (0.18–0.9mm). Sorption kinetics followed a second-order model. Sorption equilibrium isotherms could be described by the Langmuir model in some cases, whereas in others an S-shaped isotherm was observed, that did not follow the Langmuir isotherm model. The metal uptake increased with pH, with uptake capacities ranging between 0.5 and 0.9meq/g of dry peel. Due to their low cost, good uptake capacity, and rapid kinetics, citrus peels are a promising biosorbent material warranting further study. [Copyright &y& Elsevier]

Abstract: Narirutin can be successfully recovered from water-extracts of Citrus unshiu peels using the moderately polar acrylic resin, Amberlite XAD-7. The narirutin adsorption yield in this study was determined to be in excess of 95% at the following conditions for XAD-7 resin: three hours of equilibrium time, an initial narirutin concentration of at least 1500mg/l, and a resin content equal to 40 times the narirutin concentration. The adsorption isotherm of narirutin on XAD-7 resin is appropriately described by the Freundlich equation. The constants, K and n, from Freundlich’s adsorption isotherm were determined to be 7.89 and 0.34, respectively. The optimum desorption yield was found to be in excess of 89%, when 80% methanol was used as a desorption solvent. In conclusion, the recovery of narirutin from water-extracts of Citrus unshiu peels can be easily and effectively achieved via adsorption and desorption on Amberlite XAD-7, which has been shown to generate a final recovery yield of approximately 84%. The results of this study bring us closer to a batch process method for the large-scale production of narirutin. [Copyright &y& Elsevier]

Abstract: The total phenolic contents of five citrus peels (Yen Ben lemon, Meyer lemon, grapefruit, mandarin and orange) extracted by enzyme-assisted aqueous extraction were evaluated using the Folin–Ciocalteu assay. The main parameters that affected the yield of phenolics include the condition of the peels, temperature of the extraction, types of enzymes, enzyme concentration and species of citrus. Generally, grapefruit peel had the highest total phenolic contents, followed by mandarin, Yen Ben lemon, orange and Meyer lemon peel. Cell wall degrading enzymes weakened or broke down the integrity of the cell walls of the citrus peels and eased the extraction. The highest recovery using Celluzyme MX in the enzyme-assisted extraction process was up to 65.5% (about 87.9% of the solvent extraction). The total antioxidant activity (using the FRAP) assay of the phenolics enzymatically extracted from different citrus peels were compared. The phenolics in grapefruit peels had the highest total antioxidant activity, followed by Yen Ben lemon, mandarin, orange and Meyer lemon. [Copyright &y& Elsevier]

Abstract: The total phenolic contents of five citrus peels (Yen Ben lemon, Meyer lemon, grapefruit, mandarin and orange) extracted either by ethanol or by simple aqueous extraction were evaluated using the Folin-Ciocalteu assay and compared. The main parameters that affected the yield of phenolics included the condition of the peels, temperature of the extraction, solvent concentration and species of citrus. Generally, grapefruit peel had the highest total phenolic contents, followed by mandarin, Yen Ben lemon, orange and Meyer lemon peel. High extraction (about 74%) was obtained using ethanol as solvent and the percentage extraction could further be increased using a higher temperature of 80°C. In addition, the total antioxidant activity of the phenolic contents extracted from different citrus peels were investigated using the FRAP assay. The phenolics in grapefruit peels had the highest total antioxidant activity, followed by Yen Ben lemon, mandarin, orange and Meyer lemon. [Copyright &y& Elsevier]

Citrus peels can be a valuable source of pectin and narirutin. Narirutin can be extracted during the washing step of citrus peels in the pectin production process. In this study narirutin extraction conditions were optimized to maximize the narirutin extraction yield while minimized pectin loss. Washing temperature, time, and HCl concentration of the washing solution were chosen as independent variables of the central composite design. The results showed a good fit with the second-order polynomial equation, which was statistically acceptable at P<0.05 level. Pectin loss was directly correlated with the increases in temperature, time, and HCl concentration during washing procedure. Consequently, the higher the temperature and longer the time, the yield of narirutin extracted was greater, although higher HCl concentration had a negative effect on narirutin extraction yield. The present study indicated that the combination of washing temperature (62 °C), time (30 min), and the absence of HCl in the washing solution was found to be optimum conditions, yielding 0.6% of narirutin with a pectin loss of only 1.5% based on the dry citrus peels. The characterization of narirutin extracted from citrus peels was performed using HPLC and NMR. [Copyright &y& Elsevier]

Polymethoxyflavones (PMF) are a group of flavonoids isolated from citrus peels that show crystallization properties. The purpose of this study was to investigate the impact of PMF crystallization on the microstructure, stability and bioaccessibility of PMF-loaded high internal phase emulsions (HIPE) stabilized using protein and polysaccharide complexes. To improve the loading capacity of PMF, a HIPE stabilized using biopolymeric complexes was developed as a container for PMF at concentrations ranging from 1 to 4%. At supersaturation, low-density crystals remained dispersed throughout the HIPE while high-density crystals formed a three-dimensional network that disrupted the oil-in-water interface. Based on the microstructure and the rheological studies, the density of the crystals affected the stability properties. The storage temperature significantly influenced the stability of the PMF-containing HIPE system. The simulated lipolysis study showed that the bioaccessibility of crystalline PMF in a HIPE stabilized using protein-polysaccharide complexes was lower than that of solubilized PMF, indicating that the dissolution of PMF could significantly affect their bioaccessibility with simulated digestion conditions. To conclude, crystal formation in a lipid-rich delivery system affected the stability during storage, as well as the dissolution with simulated digestion condition. [Display omitted] • PMF crystallizes in MCT oil and in HIPE-complexes. • PMF crystals grew rapidly at supersaturated concentration at high temperature. • PMF crystallization affected the stability and rheological properties of HIPE. • Large PMF crystals in the HIPE reduced the bioaccessibility of PMF. [ABSTRACT FROM AUTHOR]

Agro-industrial waste is among the most abundant and accessible sources of biomass for conversion to solid biofuel, but sustainable bioenergy must be highly efficient. Therefore, the high and low heating value of briquettes produced from citrus peels (pear orange, ponkan tangerine, tahiti lemon), rice and yellow potato was evaluated, both from conventional and organic cultivation. For this, apparent density, total moisture and ash content of twelve compositions were determined. Compressive strength and smoke density using Ringelmann scale were also determined. In addition, the amount of nutrients (N, P, K, Ca and Mg) and heavy metals (Cu, Zn, Fe, Mn, Pb and Al) from the ashes of five samples were measured by FAAS. The high heating value of the specimens varied between 14.6 and 17.2 MJ/kg and low heating value between 13.1 and 15.8 MJ/kg, with the wood between 7.12 and 10.47 MJ/kg, and all samples presented suitable maximum resistance for the storage and handling of solid biofuel for domestic use. Although the nutrients are present in the samples, it was observed that the biomasses of organic cultivation had higher nitrogen content, and the values of Cu, Zn, Fe, Pb and Al were lower in the samples, and in other nutrients variations in quantities occurred. The smoke density for solid biofuel with biomass from organic cultivation was lower than those found in specimens from conventional cultivation. All the briquettes developed showed capability to replace traditional sources of heat. Image 1 [ABSTRACT FROM AUTHOR]