Supplementary Information Review Modern extraction and purification techniques for obtaining high purity food grade bioactive compounds and value-added co-products from citrus wastes Neelima Mahato1*, Mukty Sinha 2†, Kavita Sharma3†, Rakoti Koteswararao2†, Moo Hwan Cho1 School of Chemical Engineering, Yeungnam University, Gyeongsan, Republic of Korea38541; neelapchem@gmail.com; mhcho@ynu.ac.kr 2 Department of Medical Devices, National Institute of Pharmaceutical Education and Research, Ahmedabad, Palej, Gandhinagar, India-382 355; muktys@gmail.com, Kingpharmatech@gmail.com 3 Department of Chemistry, Idaho State University, Pocatello 83209, ID, USA; sharkum2@isu.edu * Correspondence: Neelima Mahato; neelapchem@gmail.com; Tel.: (+82-010-2798-8476) 1 † Contributed equally as second author Figure S-1: Major citrus producing countries in the world [1-3]. Figure S-2: (a). Origin and spread of citrus fruits across the globe from Himalayan foot hills in India and Southeast re gions of China [4,5]; (b): The native citrus fruits, and (c and d): cultivated and hybrid varieties. Photographs are collect ed from and labelled according to the information available at Sogwipo Citrus Museum, Jeju, South Korea Figure S-3: (a) Cross between the native varieties and evolution of hybrid variants in citrus, and (b) list of main citrus varieties cultivated globally [4,6] Table S-1: General description and principle of different methods and techniques used in the extraction of valuable compounds from citrus Method Principle Working condition Ref. Conventional solvent extraction Limitations: • Longer extraction time, requirement of costly and high purity solvent, • Evaporation of the huge amount of solvent, low extraction selectivity • Thermal decomposition of thermolabile compounds Soxhlet Extraction ➢ For extracting valuable bioactive compounds from various natural sources. ➢ A small amount of dry sample is placed in a thimble, thimble is then placed in distillation flask which contains the solvent of particular interest; After reaching to an overflow level, the solution of the thimbleholder is aspirated by a siphon; Siphon unloads the solution back into the distillation flask. ➢ The solution carries extracted solutes into the bulk liquid. ➢ Solute remained in the distillation flask and solvent passes back to the solid bed of plant. ➢ The process runs repeatedly until the extraction is complete Water as solvent, temperature 100° C; duration 6 – 10 h [7], [8] Maceration ➢ Grinding of plant materials into small particle to increase the surface area for proper mixing with solvent. ➢ In the process, appropriate solvent (menstruum) is added in a closed vessel. At room temperature; solvent – methanol, ethanol, water; duration 10-24 h [7] ➢ The liquid is strained off but the marc which is the solid residue of this extraction process is pressed to recover large amount of occluded solutions. ➢ The obtained strained and the press out liquid are mixed and separated from impurities by filtration. ➢ Occasional shaking in maceration facilitates extraction by increase diffusion, and removes concentrated solution from the sample surface to menstruum for more extraction yield. Hydrodistillation (HD) ➢ For extraction of bioactive compounds and essential oils from plants. ➢ Performed before dehydration of plant materials. ➢ 3 types of HD- water distillation, water and steam distillation and direct steam distillation ➢ The plant materials are packed in a still compartment; water is added in sufficient amount and then brought to boil. OR, direct steam is injected into the plant sample. ➢ Hot water and steam act as the main influential factors to free bioactive compounds of plant tissue. ➢ Indirect cooling by water condenses the vapor mixture of water and oil. Condensed mixture flows from condenser to a separator, where oil and bioactive compounds separate automatically from the water ➢ HD involves 3 physicochemical processes; Hydro-diffusion, hydrolysis and decomposition by heat. ➢ Limited for thermolabile compound extraction. Non-conventional extraction techniques Only water used as solvent, 90 – 100° C; Organic solvents are not involved [9], [10] Ultrasound➢ Waves pass through a medium by creating compression and expansion; assisted extraction produces cavitation, which means production, growth and collapse of (UAE) bubbles. ➢ A large amount of energy can produce from the conversion of kinetic energy of motion into heating the contents of the bubble at high temperature ➢ The extraction mechanism involves two main types of physical phenomena, (a) the diffusion across the cell wall and (b) rinsing the contents of cell after breaking the walls Sound wave in range of 20 kHz to 100 MHz; Working temperature 5000 K; pressure 1000 atm; heating and cooling rate above1010 K/s. Pulsed-electric ➢ Suspension of a living cell in electric field, an electric potential passes field extraction through the membrane of that cell; based on the dipole nature of (PEF) membrane molecules, electric potential separates molecules according to their charge in the cell membrane. ➢ After exceeding a critical value of approximately1 V of transmembrane potential, repulsion occurs between the charge carrying molecules that form pores in weak areas of the membrane and causes drastic increase of permeability Electric field -500 and [14], 1000 V/cm; for 10-4–10-2 s [15], very less increase in [16] temperature Enzyme-assisted extraction (EAE) ➢ For compounds retained in the polysaccharide-lignin network by hydrogen or hydrophobic bonding ➢ The addition of specific enzymes like cellulase, a-amylase, and pectinase during extraction enhances recovery by breaking the cell wall and hydrolyzing the structural polysaccharides and lipid bodies ➢ two approaches for enzyme-assisted extraction: (1) enzyme-assisted aqueous extraction (EAAE) and (2) enzyme-assisted cold pressing (EACP) ➢ EAAE methods for the extraction of oils from various seeds Enzymes used for extraction: cellulase, aamylase, and pectinase, at room temperature [11], [12], [13] [17,18 ] [1925] ➢ In EACP technique, enzymes is used to hydrolyze the seed cell wall, ➢ enzyme composition and concentration, moisture content of plant materials, particle size of plant materials, solid to water ratio, and hydrolysis time are key factors for extraction ➢ eco-friendly technology for extraction of bioactive compounds and oil as water used as solvent [26,27 ] Microwave assisted extraction ➢ The principle of heating is based upon its direct impacts on polar materials; Electromagnetic energy is converted to heat following ionic conduction and dipole rotation mechanisms; During ionic conduction mechanism heat is generated because of the resistance of medium to flow ion. ➢ Due to ionic conduction and movement heat is generated ➢ The extraction involve three sequential steps; first, separation of solutes from active sites of sample matrix under increased temperature and pressure; second, diffusion of solvent across sample matrix; third, release of solutes from sample matrix to solvent. ➢ Advantages: quicker heating for the extraction of bioactive substances from plant materials Microwaves frequency range 300 MHz to 300 GHz. Pressurized liquid extraction /pressurized fluid extraction / accelerated fluid extraction (ASE)/ enhanced solvent ➢ Application of high pressure to remain solvent liquid beyond their normal boiling point. High pressure facilitates the extraction process. ➢ The higher extraction temperature can promote higher analyte solubility by increasing both solubility and mass transfer rate and, also decrease the viscosity and surface tension of solvents, thus improving extraction rate ➢ decrease time consumption and solvent use; preferred for extraction of polar compounds Ethanol and water [28(70:30) at 50–150 °C; 31] water at 50–130 °C extraction (ESE)/ and high pressure solvent extraction (HSPE) Supercritical Fluid ➢ Supercritical fluid possesses gas-like properties of diffusion, viscosity, Extraction (SFE) and surface tension, and liquid-like density and solvation power, suitable for extracting compounds in a short time with higher yields ➢ The system consists of a tank of mobile phase, CO2, a pump to pressurize the gas, co-solvent vessel and pump, an oven containing extraction vessel, a controller to maintain the high pressure inside the system and a trapping vessel. CO2 (31 °C); pressure 100 and 450 bar [3236] Sub Critical water ➢ SCW have high density, high reactivity, and good solubility for a series of (SCW) extraction organic compounds and high catalytic activity. ➢ Citrus fruit with distilled water placed in a vessel which can withstand the pressure, after tightly closing, the vessel was placed in an extractor, the extraction performed in SCW at given temperature range and pressure. ➢ After achieving desired conditions, the vessel immediately and taken out from the oven and cooled to room temperature. ➢ Then the extracts centrifuged and the supernatants stored at 4°C. Hot water; temperature range 100 and 374°C under high pressure to maintain its liquid state (critical point of water, 22.4MPa and 374°C) [37,38 ] Microwave irradiation power: 135W- 445W; time 5-10 min [39,40 ] Microwave Steam Distillation or microwave ‘dry’ distillation ➢ Used to obtain essential oils from aromatic herbs ➢ Involves placing fresh vegetable material in a microwave reactor. The internal heating of the in situ water within the plant material distends it and makes the glands and oleiferous receptacles burst. (MSD) Cold Pressing ➢ This process thus frees essential oil, which is entrained by the in situ water of the plant material by azeotropic distillation. ➢ The vapor then passes through a condenser outside the microwave cavity, where it condensed. ➢ The distillate is collected continuously in a receiving flask. ➢ The epidermis and oil glands lacerated with a needle, creating areas Low pressure, room [39,41 of compression in the peel surrounded by areas of lower pressure, temperature, water used ] across which the oil flows to the exterior. as solvent ➢ The oil was carried down to a decantation vessel in a stream of water, the emulsion collected and separated by centrifugation. ➢ The essential oil collected, dried over anhydrous sodium sulphate and stored at 4 °C until used. Simultaneous saccharification and fermentation (SSF) ➢ The technique used for the production of ethanol from Citrus waste; ➢ It combines enzymatic hydrolysis with fermentation in the same vessel at the same time. ➢ Enzymes hydrolyze polysaccharides into sugars which immediately consumed by yeast to produce ethanol. ➢ Hydrolysis rates increases by reducing product inhibition of enzymes and reduces container usage by combining the saccharification and fermentation into one tank. ➢ Widely used in the dry grind corn ethanol industry Saccharomyces cerevisiae [42] yeast and Escherichia coli Bacteria; 10–12 rpm at 37 °C. Supercritical CO2 (SC-CO2) extraction ➢ Ultrasonic techniques can enhance SC-CO2 extraction ➢ Both extraction method applied together ➢ Yield is more compare to individual process Ultrasonic power outputs 0 to 400W; maximal [43] enhanced by ultrasound resistant pressure 35MPa; temperature 55 ◦C Microwave hydro- ➢ Combination of microwave heating and gravity working at atmospheric diffusion and pressure. The plant material is directly placed in a microwave reactor gravity without any added solvent or water; heating of thein situ water within (MHG) the plant material distends the plant cells and rupture of the glands and cell receptacles; heating frees molecules of interest together with in-situ water, i.e., hydro-diffusion, allows the extract to diffuse outside the plant material and ➢ Extract drop by earth gravity out of the microwave reactor through the perforated Pyrex disc. No solvent used; microwave power 500W for15 min [44] Figure S-4. Schematic representation of different extraction techniques Table S-2: Estimation and analysis of the products obtained from extraction Type of activity Method of estimation Expressed in Units Ref Diluted extract of orange, distilled water and Folin–Ciocalteau reagent (2 N) mg of gallic acid added; after 5 min of incubation at room temperature, solution of Na2CO3 equivalents (GAE) per 100 g of weight of (2% v/v) and distilled water added to the mixture and incubated for 90 min; orange peel. after incubation, absorbance measured at 750 nm. [37,45, 46] Ferric Reducing Ability Assay (FRAP) FRAP reagent prepared as a mixture of 0.1 M acetate buffer (pH 3.6), 10 mM of 2,4,6-tris(2-pyridyl)-s-triazine, and 20 mM ferric chloride (10:1:1, v/v/v). For the assay, 1.9 mL of reagent added to 0.1 mL of extract. Absorbance at 593 nm, measured;6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) solution used to perform the calibration curves. Trolox equivalent antioxidant capacity (TEAC) milligrams per gram of DW [46,47] 2,2-azinobis-(3ethylbenzothiazolin e-6-sulfonate) (ABTS)Free Radical Scavenging Assay A decolorization assay; To oxidize the colorless ABTS to the blue-green ABTS radical cation, ABTS (7 mM) mixed with potassium persulfate and kept for 12-16 h at room temperature in the dark; for the analysis, the ABTS solution diluted with ethanol; the diluted ABTS solution added to the extract (diluted 5 times by 80 % methanol), the mixture stirred for 30 s and allowed to stand for 15 min at room temperature, and then the absorbance reading determined at 734 nm. Trolox equivalent antioxidant capacity (TEAC) milligrams per gram of DW [47] Reduction of Molybdenum Total antioxidant capacity measurement based on the ability of potent IC50 values antioxidant to reduce molybdenum ions. The results are presented as IC50 Total Phenolics by Folin-Ciocalteu spectrophotometric method Antioxidant activity [48] values that indicate the concentration of extracts that reduces the 50% of molybdenum. Catechin used as standard probe. 2,2-dephenyl-1picrylhydrazyl (DPPH) Radical Scavenging Activity After mixing the citrus extract with DPPH radical in ethanol for 10 min, the Percentage utilization of [37] absorbance of the sample measured at 517 nm. The Radical Scavenging DPPH radical Activity expressed as percentage according to the following formula: % RSA= (1 – sample OD/control OD)×100. Reducing Power The Citrus extract, phosphate buffer (pH 6.6), and potassium ferricyanide Reduced concentration [37] solution mixed and incubated at 50 °C for 20 min. A trichloroacetic acid of Fe3+ ions solution added to the mixture and centrifuged. The resulting supernatant (1.0 ml) mixed with distilled water (1.0 ml) and a ferric chloride solution (0.1 ml), and then the absorbance measured at 700 nm. Hydroxyl radical assay Hydroxyl radicals obtained by the Fenton reaction and detected by spin Percentage trapping in a system consisting of H2O2 (2 mM), FeCl2 (0.3 mM), DMF and 5,5-dimethyl-1-pyroline-Noxide, DMPO (112 mM) as control sample. The influence of extract on the amounts of hydroxyl radicals trapped by DMPO is studied by adding the DMF solution of the extract to the reaction system in the concentration range of 0.05 – 2.0 mg/ml. ESR spectra recorded 2.5 min after mixing on an ESR spectrometer. The scavenging Activity of • OH(SA.OH) value of the extract defined as: SA• OH (%)= 100 × (H0 – H×) / H0, Where, H0 and H× are the height of the second peak in the ESR spectrum of DMPO/•OH spin adduct of the samples without and with extract, respectively. [49] Thiobarbituric Lipid oxidation of sample assessed by 2-thiobarbituric acid Method: An mg of malondialdehyde Acid-Reactive aliquot of sample homogenized with Tricoloro acetic acid (5 %) and per kg of sample Substances (TBARS) butylated hydroxyanisole (BHA) (0.8 %) on an ultrasonic bath for 5 min and then centrifuged for 5 min at 3000 rpm; the supernatant added to TBA (0.8 %) and heated in water bath (70 °C) for 30 min for pink color development. The tube cooled and then the absorbance measured at 532 nm. TBARS calculated from a standard curve of malondialdehyde freshly prepared by acidification of ,1,3,3-tetraetoxypropane in the range from 0.006 to 0.299 μg/ml. Peroxide value (PV) The lipid samples dissolved in glacial acetic acid: chloroform (3/2 v/v), and meq. KI solution (14-g KI/10 mL distilled water) added; the mixture titrated lipid against 0.01 N sodium thiosulphate with the presence of starch as an indicator. Peroxide value calculated as: PV(meq. peroxide O2/kg lipid)= (V – B × Nf/W) × 1000; Where, V = amount of thiosulphate, B = spent thiosulphate for the blank, W = weight of the sample (g), Nf = the normality for sodium thiosulphate. peroxide [49] [50] O2/kg [51] Superoxide radical Peel extract at different concentrations (25-400 mg/mL) added to 1 mL Percentage inhibition of [52] scavenging power Na2CO3 (5 %), 0.3 mL EDTA (0.5%), and 0.4 mL nitrobluetetrazolium (NBT). superoxide radical The absorbance of the mixture measured immediately at 560 nm. The reaction initiated by the addition of 0.4 mL hydroxlylamine hydrochloride and incubated at 25 °C for 5 minutes; NBT reduction determined with a spectrophotometer at 560 nm. A parallel control (without extract) and standard ascorbic acid analyzed in a similar manner. The percent scavenging activity calculated as follows: A1 Percentage inhibition of superoxide radical = [1 − ] × 100 A0 Where, A1 is the absorbance of extract sample and A0is the absorbance of control. Lipolytic Effects Sample mixed with 900 μL of chloroform and 50 μL of olive oil in a tightly Percent of oleic acid screwed cap vessel. The control sample is prepared using chloroform instead of peel oils or authentic compounds. 4-(4-Hydroxyphenyl)-2-butanone (raspberry ketone) is employed as a standard compound to examine the lipolytic effects; 20 mM 4-(4-hydroxyphenyl)-2-butanone in chloroform added to the reaction mixture (final concentration of 1 mM); The mixture is shaken and left to stand for 60 min at 37 °C in an incubator. After 60 min, the sample subjected to GC analysis. The lipolytic effect is investigated by evaluating the increase of peak area at the gas chromatogram. [53] Antifouling agent The test is done on mussels (Mytilus edulis), a leading shellfish. The test is Percentage inhibitory performed to evaluate the adhesion inhibiting effect on the shellfish, which activity cannot adhere to the surface in presence of the extract. The percentage shrinkage of roots of shell mussels is recorded. [54] The paper disc diffusion method employed to determine the antimicrobial activity of the essential oils. For the assays, cultures of the following microorganisms are used: two Gram positive (S. aureus and S. epidermidis) and two Gram-negative (Pseudomonas aeruginosa and E. coli) Bacteria, and two yeasts (Saccharomyces cerevisiae and Candida albicans). Suspensions of the tested microorganisms are spread onto solid media plates. Filter paper discs are individually impregnated with 50 ml essential oil then lay onto the surfaces of the inoculated plates. At the end of the incubation time (24 h at 37 °C for bacteria, 48 h at 25 °C for yeasts), positive antibacterial and [39] by mussels inhibitory effect test Antimicrobial Activity Width (mm, including the diameter of the disc) of the zone of inhibition after incubation ? ? ? antifungal activities established by the presence of measurable zones of inhibition. Total Flavonoids Content An aliquot of diluted sample solution mixed with distilled water and 5 % mg of rutin equiv. per NaNO2 solution. After 6 min, 10 % AlCl3 solution added and allowed to 100 gram of fresh peel stand for few min, then 4 % NaOH solution added to the mixture. Immediately, water is added to bring the final volume to 5 mL, and then the mixture is thoroughly mixed and allowed to stand for another 15 min and absorbance taken at 510 nm. Rutin is used as standard compound for the quantification of total flavonoids. [55] Ash content determination 1–2 g of the sample accurately weighed into a weighed empty crucible Percent of ash separately. The crucible placed in a furnace and heated for 3–4 h at 600 °C to burn off all the organic matter. The crucible is taken out of the furnace and placed in a desiccator to cool and weighed. Weight of ash Ash content (%) = × 100 weight of sample [56] Equivalent weight determination Weighed pectin sample and transferred into a 250 mL conical flask and Equivalent to NaOH ethanol, NaCl added to it. Later, distilled water and few drops of phenol red molarity indicator are added to the mixture. The solution slowly titrated (to avoid possible deesterification) with 0.1 M NaOH to endpoint of pink color. weight of pectin sample Equivalent weight = × 1000 ml of alkali × Normality of alkali [56] Methoxyl content determination To the neutral solution titrated for equivalent weight, containing pectic Percentage of methoxyl substances, 0.25 N NaOH is added and shaken thoroughly; allowed to stand content [56] for 30 min at room temperature in a stoppered flask; after that 0.25 N HCl is added. The contents are titrated with 0.1 N NaOH until pink color as end point. ml of alkali × normality of alkali × 3.1 Methoxyl content (%) = weight ofsample Moisture content determination A dried empty petri dish dried in an oven, cooled in a desiccator and Percentage of water weighed. Five grams of the pectin samples transferred into the crucibles in content the oven and heated at 130 °C for 1 h. The petri dish cooled to room temperature in a desiccator and weighed. Wt. of the pectin sample after drying Moisture content (%) = × 100 Wt. of pectin sample [56] Alkalinity assay Anhydrounic acid To determine the alkalinity of ash, the ash is dissolved in 25 mL of 0.1 N Percentage of carbonate HCl. The contents are heated and cooled to room temperature. This mixture is titrated with 0.1 N NaOH using phenolphthalein indicator until end point of orange color. Volume of NaOH × 60 × 60 Alkalinity (%) as carbonate = Wt. of ash × 1000 [56] Anhydrounic acid m. e. alkali for free acid × m. e. alkali for saponofication × m. e. titrable ash = Wt. of sample (mg) where, m.e.= mili equivalent Galacturonic acid (GA), sugars and ethanol contents 10 mL of sample centrifuged at 4000 rpm and 4 °C for 8 min, and the In percent supernatant filtered to determine sugars, GA, and ethanol. The sugars [57] (glucose, fructose, galactose, arabinose, sucrose, rhamnose, and xylose) and galacturonic acid (GA) are analyzed by ionic chromatography. Ethanol is quantified by injecting 0.8 L of filtered supernatant into a gas chromatograph with FID detector. The ethanol standard curve was determined for concentrations between 0.02 and 5% (v/v). GA Galacturonic acid is determined by m-hydroxydiphenyl method. Samples mixed thoroughly with 0.125 M sodium tetraborate solution (in concentrated sulfuric acid) in an ice bath. The mixtures heated in a boiling bath for 5 min and subsequently cooled in an ice bath; the mixtures added with 0.15% mhydroxydiphenyl (in 0.5 % NaOH) and mixed; A pink color develops during 5 min. After that, the absorbance recorded at 520 nm. μg Total sugars By phenol–sulfuric acid method: Samples mixed thoroughly with aqueous Microgram per milliliter solution of phenol of 5 %. Then concentrated sulfuric acid quickly introduced into the reaction medium. After homogenization, the mixtures heated in a boiling bath for 5 min, cooled in an ice bath and placed in the dark for 30 min. An orange color appears. The absorbance recorded at 492 nm. A standard curve was obtained using glucose at 25, 50, 100 and 200 μg mL-1. [58] Ethanol analysis Quantified in a gas chromatography [59,60] Degree of esterification (DE) Pectin dissolved in ethanol, 1 g NaCl and some drops of phenolphthalein. Percentage The solution is titrated with 0.1 N NaOH, V1; then NaOH was added in this solution which stirred at room temperature for 30 minutes. After that, 0.25 N Volume by volume [58] [61] [58] HCl is added and the solutions shaken until the pink color disappeared. The solution is titrated again with 0.1 N NaOH, V2; DE value is calculated according to the following formula below: V2 × 100 % DE = V1 + V2 Total dry matter Citrus pulp pellets obtained after fermentation and filtration, used to Weight content determine total dry matter by drying at 70 °C for 20 h, followed by drying in [60] a vacuum oven at 70 °C for 1 h. Para-anisidine value (PAV) The sample dissolved in n-hexane, and the absorbance of the mixture Gram -1 measured at 350 nm (A1). Para-anisidine reagent (1mL) added to 5 mL of the mixture and held in the dark for 10 min before absorbance reading (A2) at 350 nm. The result is calculated as PAV= 25 (1.2A2- A1)/m, Where, m represents mass of sample oil. [51] d-Limonene analysis Scott method: based on a bromination reaction with the double bonds of the ml molecule. For most flavor and specialty chemical applications, d-limonene is analyzed instrumentally by GC/MS. [62] Pectin content Crude pectin added in 250 ml flask, then adding 0.1N NaOH and soaked for Percentage 7 hours, then added 1 N CH3COOH and CaCl2 after 5 minutes and kept it for 1 hour; the solution is boiled, filtered and dried; Calcium pectate is washed with hot water until not having Cl– ion in the solution, dried at 105°C. The pure level of pectin is calculated according to the following formula below: [61] m × 0.92 × 100 M P (%): the pure level of pectin m (g): weight of calcium pectate M (g): weight of crude pectin 0.92: pectins have 92% in volume of calcium pectate P= Figure S-5: Classification of major citrus phytochemicals extracted from different parts of citrus wastes Figure S-6: Steps involved in the different extraction method employed for total polyphenolic content from citrus peels [63-65] Figure S-7: Molecular structures of major flavonoids: aglycones, glucosides, and polymethoxylated forms Figure S-8: Steps involved in the extraction and purification of flavonoids from citrus peels [64, 66-74] Figure S-9: Molecular structures of phenolic acids found in citrus fruits Figure S-10: Steps involved in the extraction of total phenols, anthocyanins and phenolic acids from citrus waste [47, 75-77] Figure S-11: Molecular structures of common citrus (a) limonoid aglycones and (b) limonoid glucosides [78] Figure S-12: (a-b) Steps involved in the different extraction methods for limonoids from citrus peels and seeds; (b-g) Limonoid aglycones, and (h-l) limonoid glucosides [79,80] Figure S-13: Molecular structures of coumarins found in citrus wastes Figure S-14: Molecular structure of synaphrene and p- synaphrene Figure S-15: Steps involved in the extraction of synaphrine [81] Figure S-16: Molecular structures of the pigments found in citrus wastes Figure S-17: Important steps in the extraction of carotenoids [82-85] Table S-3: Composition of pigments in different citrus varieties [6] Valencia orange Endocarp (15 mg/l) Tangerine Eureka Lemon Peels Endocarp Peels Endocarp (120 (27 mg/l) (186 (0.6 mg/kg) mg/kg) mg/kg) (Approximate percentage of total carotenoids) Hydrocarbons 3.1 5.8 4.2 - Phytoene 4.0 Phytofluene 13.0 6.1 7.2 3.5 α-Carotene β-Carotene 0.5 1.1 0.1 0.3 Cryptoxanthin Cryptoflavin 3-Hydroxy- α-Carotene 5.3 0.5 1.5 1.2 1.2 0.3 Lutein Zeaxanthin 2.9 4.5 1.2 0.8 Antheraxanthin Mutatoxanthin 5.8 6.2 6.3 Violaxanthin Luteoxanthin 7.4 17.0 44.0 16.0 0.3 0.2 4.1 0.4 Mono-ols 33.0 24.0 0.8 3.4 1.0 0.6 Diols 2.9 3.3 3.3 3.5 Monoetherdiols 9.7 6.2 2.2 2.8 Dietherdiols 14 24.0 3.5 9.1 Peels (1.4 mg/kg) Ruby Red Grapefruit Endocarp Peels - - 1.6 47.0 22.0 18.0 4.4 1.4 6.6 4.0 6.8 17.0 27.0 0.1 7.2 26.0 - 9.7 - 0.7 0.2 1.4 1.3 0.1 - - 0.3 - 0.9 - - - 0.7 0.4 0.2 - - 0.9 0.4 1.0 1.8 Auroxanthin 12.0 2.3 0.4 1.9 - - 0.3 1.6 0.4 1.1 - - 0.2 - 0.3 - Polyols Valenciaxanthin Valenciachromes Sinensiaxanthin 2.8 1.0 2.0 2.2 0.7 3.5 0.2 0.2 Figure S-18: Steps involved in the different extraction methods for seed oils from the citrus seeds [66,86] Figure S-19: Water soluble and insoluble volatile constituents found in citrus wastes Figure S-20: Molecular structure of main lipids found in citrus wastes Figure S-21: Steps involved in the extraction of cellulose and sugars [66,87,88] Figure S-22: Steps involved in the extraction of sugars from citrus waste [66, 86, 88, 89] Figure S-23: Extraction of inverted sugars from citrus waste [90] Figure S-24: Production of Xanthan gum from citrus waste [91] Figure S-25: Production of various important organic acids, viz., succinic acid, citric acid, lactic acid and vinegar, and vitamins from citrus waste [66,86,92-96] Figure S-26: Steps involved in the extraction, separation and isolation, and determination of different phenolic compounds [97] Figure S-27: Fragmentation pathway of 5,6,7,4’-tetramethoxyflavanone [98] References: 1. Report. Citrus fruits 2016 Summary; United States Department of Agriculture, National Agricultural Statistics Service. 2. Agriculture, U.S.D.A. Citrus: World markets and trade Foreign Agricultural Service 2019 July. 3. Distribution, E. The growth of the world’s citrus trade; Produce Citrus: 2019. 4. Wu, G.A.; Terol, J.; Ibanez, V.; López-García, A.; Pérez-Román, E.; Borredá, C.; Domingo, C.; Tadeo, F.R.; Carbonell-Caballero, J.; Alonso, R., et al. Genomics of the origin and evolution of Citrus. Nature 2018, 554, 311–316. 5. Weisskopf, A.; Fuller, D.Q. Citrus fruits: Origins and development; Springer: New York, NY, 2014. 6. Kefford, J.F. The chemical constituents of citrus fruits. Advances in Food Research 1960, 9, 285-372. 7. Azmir, J.; Zaidul, I.S.M.; Rahman, M.M.; Sharif, K.M.; Mohamed, A.; Sahena, F.; Jahurul, M.H.A.; Ghafoor, K.; Norulaini, N.A.N.; Omar, A.K.M. Techniques for extraction of bioactive compounds from plant materials: A review. Journal of Food Engineering 2013, 117, 426–436. 8. Liu, Y.; Shi, J.; Langrish, T.A.G. Water-based extraction of pectin from flavedo and albedo of orange peels. Chemical Engineering Journal 2006, 120, 203-209. 9. Vankar, P.S. Essential oils and fragrances from natural sources. Resonance 2004, 9, 30-41. 10. Silva, L.V.; Nelson, D.L.; Drummond, M.F.B.; Dufossé, L.; Glória, M.B.A. Comparison of hydrodistillation methods for the deodorization of turmeric. Food Research International 2005, 38, 1087-1096. 11. Suslick, K.S.; Doktycz, S.J. The effects of ultrasound on solids" in Advances in Sonochemistry; JAI Press: New York, 1990; Vol. 1, pp. 197-230. 12. Mason, T.J.; Paniwnyk, L.; Lorimer, J.P. The uses of ultrasound in food technology. Ultrasonics Sonochemistry 1996, 3, 253-260. 13. Nishad J.; Saha S.; Kaur C. Enzyme‐ and ultrasound‐assisted extractions of polyphenols from Citrus sinensis (cv. Malta) peel: A comparative study. Journal of Food Processing and Preservation 2019, 43, e14046. 14. Bryant, G.; Wolfe, J. Electromechanical stress produced in the plasma membranes of suspended cells by applied electrical fields. Journal of Membrane Biology 1987, 96 129-139. 15. Fincan, M.; Dejmek, P. In situ visualization of the effect of a pulsed electric field on plant tissue. Journal of Food Engineering 2002, 55, 223-230. 16. Lebovka, N.I.; Bazhal, M.I.; Vorobiev, E. Estimation of characteristic damage time of food materials in pulsed-electric fields. Journal of Food Engineering 2002, 54, 337-346. 17. Singh, R.K.; Sarker, B.C.; Kumbhar, B.K.; Agrawal, Y.C.; Kulshreshtha, M.K. Response surface analysis of enzyme-assisted oil extraction factors for sesame, groundnut, and sunflower seeds. Journal of Food Science and Technology 1999, 36, 511-514. 18. Latif, S.; Anwar, F. Physicochemical studies of hemp (Cannabis sativa) seed oil using enzyme-assisted cold-pressing. European Journal of Lipid Science and Technology 2009, 111, 1042-1048. 19. Hanmoungjai, P.; Pyle, D.L.; Niranjan, K. Enzymatic process for extracting oil and protein from rice bran. Journal of the American Oil Chemists Society 2001, 78, 817-821. 20. Rosenthal, A.; Pyle, D.L.; Niranjan, K.; Gilmour, S.; Trinca, L. Combined effect of operational variables and enzyme activity on aqueous enzymatic extraction of oil and protein from soybean. Enzyme and Microbial Technology 2001, 28, 499– 509. 21. Sharma, A.; Khare, S.K.; Gupta, M.N. Enzyme-assisted aqueous extraction of peanut oil. Journal of American Oil Chemist’s Society 2002, 79, 215-218. 22. Concha, J.; Soto, C.; Chamy, R.; Zuniga, M.E. Enzymatic pretreatment on Rose- Hip oil extraction: hydrolysis and pressing conditions. Journal of American Oil Chemist’s Society 2004, 81, 549-552. 23. Niranjan, K.; Hanmoungjai, P. Enzyme-aided aqueous extraction; ACS Publishing: 2004. 24. Dominguez, H.; Ntiiiez, M.J.; Lema, J.M. Enzyme-assisted hexane extraction of soybean oil. Food Chemistry 1995, 54, 223-231. 25. Puri, M.; Sharma, D.; Barrow, C.J. Enzyme-assisted extraction of bioactives from plants. Trends in Biotechnology 2012, 30, 37-44. 26. Jain, T. Microwave assisted extraction for phytoconstituents – An overview. Asian Journal of Research in Chemistry 2009, 2, 19-25. 27. Letellier, M.; Budzinski, H. Microwave assisted extraction of organic compounds. Analysis 1999, 27, 259-270. 28. Nieto, A.; Borrull, F.; Pocurull, E.; Marcé, R.M. Pressurized liquid extraction: a useful technique to extract pharmaceuticals and personal-care products from sewage sludge. Trends in Analytical Chemistry 2010, 29, 752-764. 29. Ibañez, E.; Herrero, M.; Mendiola, J.A.; Castro-Puyana, M. Extraction and characterization of bioactive compounds with health benefits from marine resources: macro and micro algae, cyanobacteria, and invertebrates; Springer: 2012; pp. 55-98. 30. Luengo, E.; Alvarez, I.; Raso, J. Improving the pressing extraction of polyphenols of orange peel by pulsed electric fields. Innovative Food Science & Emerging Technologies 2013, 17, 79-84. 31. Richter, B.E.; Jones, B.A.; Ezzell, J.L.; Porter, N.L.; Avdalovic, N.; Pohl, C. Accelerated solvent extraction: A technique for sample preparation. Analytical Chemistry 1996, 68, 1033-1039. 32. Hannay, J.B.; Hogarth, J. On the solubility of solid in gases. Proceeding of the Royal Society of London 1879, 29, 324-326. 33. Zosel, K. Method for separation of mixtures. 1964. 34. Sihvonen, M.; Järvenpää, E.; Hietaniemi, V.; Huopalahti, R. Advances in supercritical carbon dioxide technologies. Trends in Food Science and Technology 1999, 10, 217-222. 35. Giannuzzo, A.N.; Boggetti, H.c.J.; Nazareno, M.n.A.; Mishima, H.T. Supercritical fluid extraction of naringin from the peel of Citrus paradisi. Phytochemical Analysis 2003, 14, 221-223. 36. Herrero, M.; Mendiola, J.A.; Cifuentes, A.; Ibá˜nez, E. Supercritical fluid extraction: Recent advances and applications. Journal of Chromatography A 2010, 1217, 2495-2511. 37. Kim, J.-W.; Nagaoka, T.; Ishida, Y.; Hasegawa, T.; Kitagawa, K.; Lee, S.-C. Subcritical water extraction of nutraceutical, compounds from citrus pomaces. Separation Science and Technology 2009, 44, 2598-2608. 38. M’hiri, N.; Ioannou, I.; Ghoul, M.; Boudhrioua, N.M. Extraction methods of citrus peel phenolic compounds: a review. Food Reviews International 2014, 30, 265-290. 39. Ferhat, M.A.; Meklati, B.Y.; Farid Chemat. Comparison of different isolation methods of essential oil from Citrus fruits: cold pressing, hydrodistillation and microwave ‘dry’ distillation. Flavour Fragrance Journal 2007, 22, 494-504. 40. Shakir, I.K.; Salih, S.J. Extraction of essential oils from citrus by-products using microwave steam distillation. Iraqi Journal of Chemical and Petroleum Engineering 2015, 16, 11- 22. 41. Ferhat, M.A.; Boukhatem, M.N.; Hazzit, M.; Meklati, B.Y.; Chemat, F. Cold pressing, hydrodistillation and microwave dry distillation of citrus essential oil from Algeria: A comparative study. Electronic Journal of Biology 2016, S1, 3041. 42. Wilkins, M.R.; Widmer, W.W.; Grohmann, K. Simultaneous saccharification and fermentation of citrus peel waste by Saccharomyces cerevisiae to produce ethanol. Process Biochemistry 2007, 42, 1614-1619. 43. Yanxiang Gao; Nagy, B.; Liu, X.; Béla Simándi; Wang, Q. Supercritical CO2 extraction of lutein esters from marigold (Tagetes erecta L.) enhanced by ultrasound. Journal of Supercritical Fluids 2009, 49, 345-350. 44. Bousbia, N.; Vian, M.A.; Ferhat, M.A.; Meklati, B.Y.; Chemat, F. A new process for extraction of essential oil from Citrus peels: Microwave hydrodiffusion and gravity. Journal of Food Engineering 2009, 90, 409-413. 45. Singleton, V.L.; Rosi, J.A. Colorimetry of total phenolics with phosphomolybdic– phosphotungstic acid reagents. American Journal of Viticulture Enology 1965, 16, 144–158. 46. Li, B.B.; Smith, B.; Hossain, M. Extraction of phenolics from citrus peels I. Solvent extraction method. Separation and Purification Technology 2006, 48, 182– 188. 47. Guihua Xu; Ye, X.; Chen, J.; Liu, D. Effect of heat treatment on the phenolic compounds and antioxidant capacity of citrus peel extract. Journal of Agricultural and Food Chemistry 2007, 55, 330-335. 48. Prieto, P.; Pineda, M.; Aguilar, M. Spectrophotometric quantitation of antioxidant capacity through the formation of a phosphomolybdenum complex: specific application to the determination of vitamin E. Analytical Biochemistry1999, 269, 337-341. 49. Tumbas, V.T.; Ćetković, G.S.; Djilas, S.M.; Čanadanović-Brunet, J.M.; Vulić, J.J.; Knez, Ž.; Škerget, M. Antioxidant activity of mandarin (Citrus reticulata) peel. Acta periodica technologica 2010, 41, 1-203. 50. Dhuique-Mayer, C.; Tbatou, M.; Carail, M.; Caris-Veyrat, C.; Dornier, M.; Amiot, M.J. Thermal degradation of antioxidant micronutrients in citrus juice: kinetics and newly formed compounds. Journal of Agricultural and Food Chemistry 2007, 55, 4209-4216. 51. Yerlikayaa, P.; Gokoglu, N.; Topuz, O.K.; Gumus, B.; Yatmaz, H.A. Antioxidant activities of citrus albedo and flavedo fragments against fish lipid oxidation. Journal of Aquatic Food Product Technology 2016. 52. Safdar, M.N.; Kausar, T.; Jabbar, S.; Mumtazb, A.; Ahad, K.; Saddozai, A.A. Extraction and quantification of polyphenols from kinnow (Citrus reticulata L.) peel using ultrasound and maceration techniques. Journal of Food and Drug Analysis 2016, 1-13. 53. Choi, S. Lipolytic effects of citrus peel oils and their components. Journal of Agricultural and Food Chemistry 2006, 54, 3254-3258. 54. Oong, S.H. Environmental friendly pollution -proof agent made from citrus fruits. 2006. 55. Hussain.A.Abd El-aal, F.T.H. Food preservative activity of phenolic compounds in orange peel extracts (Citrus sinensis L.). LucrăriŞtiinţifice Seria Zootehnie 2010, 53, 233-240. 56. Bhatlu, M.L.D.; Prashant Katiyar; Singh, S.; Verma, A.K. Pre-harvest dropped kinnow (Citrus reticulata Blanco) waste management through the extraction of naringin and pectin from their peels using indigenous resin. Journal of the Institution of Engineers (India): Series A 2016, 97, 285-290. 57. MaríaBoluda-Aguilar; García-Vidal, L.; González-Castañeda, F.d.P.; LópezGómez, A. Mandarin peel wastes pretreatment with steam explosion for bioethanol production. Bioresource Technology 2010, 101, 3506–3513. 58. Zouambia, Y.; Ettoumi, K.Y.; Krea, M.; Moulai-Mostefa, N. A new approach for pectin extraction: Electromagnetic induction heating. Arabian Journal of Chemistry 2017, 10, 480–487. 59. Belisario-Sánchez, Y.Y.; A.Taboada-Rodríguez; Marín-Iniesta, F.; LópezGómez, A. Dealcoholized wines by spinning cone column distillation: phenolic compounds and antioxidant activity measured by the 1,1-diphenyl2-picrylhydrazyl method. Journal of Agricultural and Food Chemistry 2009, 57, 6770–6778. 60. MaríaBoluda-Aguilar; López-Gómez, A. Production of bioethanol by fermentation of lemon (Citrus limon L.) peel wastes pretreated with steam explosion. Industrial Crops and Products 2013, 41, 188– 197. 61. Quoc, L.P.T.; Huyen, V.T.N.; Hue, L.T.N.; Hue, N.T.H.; Thuan, N.H.D.; Tam, N.T.T.; Thuan, N.N.; Duy, T.H. Extraction of pectin from pomelo (Citrus maxima) peels with the assistance of microwave and tartaric acid. International Food Research Journal 2015, 22, 1637-1641. 62. Goodrich, R.M.; Braddock, R.J. Major by-products of the Florida Citrus Processing Industry; Food Science and Human Nutrition Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida: Florida, FSHN05-22, 2006. 63. Hegde, P.; Agrawal, P.; Gupta, P.K. Isolation and optimization of polyphenols from the peels of orange fruit. Journal of Chemical and Pharmaceutical Sciences 2015, 8, 463-468. 64. Khan, M.K.; Abert-Vian, M.; Fabiano-Tixier, A.S.; Dangles, O.; Chemat, F. Ultrasound-assisted extraction of polyphenols (flavanone glycosides) from orange (Citrus sinensis L.) peel. Food Chemistry 2010, 119, 851-858. 65. Xu, G.; Ye, X.; Chen, J.; Liu, D. Effect of heat treatment on the phenolic compounds and antioxidant capacity of citrus peel extract. Journal of Agricultural and Food chemistry 2007, 55, 330-335. 66. Shan, Y. Comprehensive utilization of citrus by-products; Academic Press Elsevier: London, UK, 2016. 67. Nafisi-Movaghar, K.; Druz, L.L.; Victoria, C.P. Process for conversion of citrus peels into fiber, juice, naringin and oil. US 8481099B2 (Patent) 2013. 68. Service, A.R. Chemistry and technology of citrus, citrus products and byproducts; US Government Printing Office: Washington DC, 1956. 69. Rosa J. D.P; Ruiz-Palomino P.; Arriola-Guevara E.; García-Fajardo J.; Sandoval G.; Guatemala-Morales G.M. A green process for the extraction and purification of hesperidin from Mexican lime peel (Citrus aurantifolia Swingle) that is extendible to the Citrus genus. Processes 2018, 6, 266(1-13). 70. Hoshino, M.; Suetsugu, T.; Iwai, H.; Takamizu, A.; Tanaka, M.; Quitain, A.; Sasaki, M.; Goto, M. Extraction of citrus flavonoids from peel of Citrus junos using supercritical carbon dioxide with polar solvent. Transactions of the Materials Research Society of Japan 2014, 39, 309-311. 71. Nandan, M.P.; Meena, V. Extraction, modelling and purification of flavonoids from Citrus medica peel. International Journal of Applied Sciences and Biotechnology 2015, 3, 588-591. 72. Londoño-Londoño, J.; Lima, V.R.d.; Lara, O.; Gil, A.; Pasa, T.B.C.; Arango, G.J.; Pineda, J.R.R. Clean recovery of antioxidant flavonoids from citrus peel: Optimizing an aqueous ultrasound-assisted extraction method. Food Chemistry 2010, 119, 81-87. 73. Inoue, T.; Tsubaki, S.; Ogawa, K.; Onishi, K.; Azuma, J.-i. Isolation of hesperidin from peels of thinned Citrus unshiu fruits by microwave-assisted extraction. Food Chemistry 2010, 123, 542-547. 74. Cheigh, C.I.; Chung, E.Y.; Chung, M.S. Enhanced extraction of flavanones hesperidin and narirutin from Citrus unshiu peel using subcritical water. Journal of Food Engineering 2012, 110, 472-477. 75. Magwaza, L.S.; Oara, U.L.; Cronje, P.j.R.; Landahl, S.; Ortiz, J.O.; Terry, L.A. Rapid methods for extracting and quantifying phenolic compounds in citrus rinds. Food Science and Nutrition 2016, 4, 4-10. 76. Li, B.B.; Smith, B.; Hossain, M.M. Extraction of phenolics from citrus peels. I. Solvent extraction method. Separation and Purification Technology 2006, 48, 182– 188. 77. Bocco, A.; Cuvelier, M.-E.; Richard, H.; Berset, C. Antioxidant activity and phenolic composition of citrus peel and seed extracts. Journal of Agricultural and Food Chemistry 1998, 46, 2123-2129. 78. Sharma, K.; Mahato, N.; Cho, M.H.; Lee, Y.R. Converting citrus wastes into value added products: Economical and environment friendly approaches. Nutrition 2017, 34, 29-46. 79. Patil, B.S.; Yu, J.; Dandekar, D.V.; Toledo, R.T.; Singh, R.K.; Pike, L.M. Citrus bioactive limonoids and flavonoids extraction by supercritical fluids. Potential Health Benefits of Citrus, ACS Symposium Series 2006, 936, 18-33. 80. Jayaprakasha, G.K.; Brodbelt, J.S.; BhatBhimanagouda, N.G.; Patil, S. Methods for the separation of limonoids from citrus. In Proceedings of Potential Health Benefits of Citrus; pp. 34-51. 81. Andrade, A.S.; Schmitt, G.C.; Rossato, L.G.; Russowsky, D.; Limberger, P. Gas chromatographic method for analysis of p-synephrine in Citrus aurantium L. products. Chromatographia 2009, 69, 225-229. 82. Johnson, J.D.; Viale, H.E.; Wait, D.M. Method for extracting carotenoid pigments from citrus oils. 1978. 83. Shukla, P.; Gawande, S.; Thorat, A. Extraction, Identification and Utilization of Pigments extracted from citrus wastes. International Journal of Science and Research 2016, 5, 840-847. 84. Boukroufa, M.; Boutekedjiret, C.; Chemat, F. Development of a green procedure of citrus fruits waste processing to recover carotenoids. ResourceEfficient Technologies 2017, 3, 252–262. 85. Johnson, J.D.; Viale, H.E.; Wait, D.M. Method for extracting carotenoid pigments from citrus oils. 1977. 86. Service), A.A.R. Chemistry and technology of citrus, citrus products and byproducts; United States Department of Agriculture: Washington, DC, 1962. 87. Hiasa, S.; Iwamoto, S.; Endo, T.; Edashige, Y. Isolation of cellulose nanofibrils from mandarin (Citrus unshiu) peel waste. Industrial Crops and Products 2014, 62, 280–285. 88. Kumar, C.S.C.; Mythily, R.; Chandraju, S. Extraction of carbohydrate from sweet orange peels (Citrus sinensis L.) and their identification via LC /MS and thin layer chromatographic analysis. Biosciences Biotechnology Research Asia 2011, 8, 709-715. 89. Velasco, D.; Senit, J.J.; Torre, I.d.l.; Santos, T.M.W.; Yustos, P.; Santos, V.E.; Ladero, M. Optimization of the enzymatic saccharification process of milled orange wastes. Fermentation 2017, 3, 37. 90. Milch, R.A.; Guerry-Kopecko, P.; Koeble-Smith, C.; Sybert, E.M. Preparation of high fructose syrups from citrus residues. 1985. 91. Bilanovic, D.; Shelef, G.; Green, M. Xanthan fermentation of citrus waste. Bioresource Technology 1994, 48, 169-172. 92. Moriguchi, M. Fermentative production of pyruvic acid from citrus peel extract by Debaryomyces coudertii. Agricultural and Biological Chemistry 1982, 46, 955 -961. 93. Oguntoyinbo, S.I.; Babajide, J.M.; Adenekan, M.K.; Ajayi, J.O.; Kareem, S.O.; Ayelaagbe, I.O.; Atanda, O.O.; Bodunde, G. Chemical properties of vinegar produced from sweet orange peels (Citrus sinensis). Journal of Agricultural and Veterinary Sciences 2011, 3, 51-61. 94. Torrado, A.M.; Cortés, S.; Salgado, J.M.; Max, B.; Rodríguez, N.; Bibbins, B.P.; ConvertiI, A.; Domínguez, J.M. Citric acid production from orange peel wastes by solid-state fermentation. Brazilian Journal of Microbiology 2011, 42, 394-409. 95. Kagan, J.J.; Pilnik, W.; Smith, M.D. Citrus by-products, lactic acid production by fermentation of citrus peel juice. Journal of Agricultural and Food Chemistry 1960, 8, 236-238. 96. Patsalou, M.; Menikea, K.K.; Makri, E.; Vasquez, M.I.; Drouza, C.; Koutinas, M. Development of a citrus peel-based biorefinery strategy for the production of succinic acid. Journal of Cleaner Production 2017, 166, 706-716. 97. Kuo, P.-C.; Liao, Y.-R.; Hung, H.-Y.; Chuang, C.-W.; Hwang, T.-L.; Huang, S.C.; Shiao, Y.-J.; Kuo, D.-H.; Wu, T.-S. Anti-inflammatory and neuroprotective constituents from the peels of Citrus grandis. Molecules 2017, 22, 967-967. 98. Li, S.; Lo, C.Y.; Ho, C.T. Hydroxylated polymethoxyflavones and methylated flavonoids in sweet orange (Citrus sinensis) peel. Journal of Agricultural and Food Chemistry 2006, 54, 4176-4185. View publication stats