Effect of Ionic Liquids in the Elaboration of Nanofibers of Cellulose Bagasse from Agave tequilana Weber var. azul by Electrospinning Technique.

The objective of this paper was to report the effect of ionic liquids (ILs) in the elaboration of nanofibers of cellulose bagasse from Agave tequilana Weber var. azul by the electrospinning method. The ILs used were 1-butyl-3-methylimidazolium chloride (BMIMCl), and DMSO was added as co-solvent. To observe the effect of ILs, this solvent was compared with the organic solvent TriFluorAcetic acid (TFA). The nanofibers were characterized by transmission electron microscopy (TEM), X-ray, Fourier transform-infrared using attenuated total reflection (FTIR-ATR) spectroscopy, and thermogravimetric analysis (TGA). TEM showed different diameters (ranging from 35 to 76 nm) of cellulose nanofibers with ILs (CN ILs). According to X-ray diffraction, a notable decrease of the crystalline structure of cellulose treated with ILs was observed, while FTIR-ATR showed two bands that exhibit the physical interaction between cellulose nanofibers and ILs. TGA revealed that CN ILs exhibit enhanced thermal properties due to low or null cellulose crystallinity. CN ILs showed better characteristics in all analyses than nanofibers elaborated with TFA organic solvent. Therefore, CN ILs provide new alternatives for cellulose bagasse. Due to their small particle size, CN ILs could have several applications, including in food, pharmaceutical, textile, and material areas, among others.

Nanoencapsulation of Eggplant (Solanum melongena L.) Peel Extract in Electrospun Gelatin Nanofiber: Preparation, Characterization, and In Vitro Release.

This study describes the preparation and characterization of eggplant peel extract-loaded electrospun gelatin nanofiber and study of its in vitro release. Results obtained by scanning electron microscopy (SEM) and transmission electronic microscopy (TEM) micrograph revealed that eggplant peel extract-loaded electrospun gelatin nanofiber is in nanometric range with an average diameter 606.7 ± 184.5 and 643.6 ± 186.7 nm for 20 and 33.3 mg mL-1 of extract addition, respectively. Moreover, the incorporation of extract improved morphology by being smooth, homogeneous, and without account formation compared to nanofibers without extract (control). Fourier transform-infrared (FT-IR) spectra indicated that interaction exists between electrospun gelatin nanofiber and eggplant peel extract by hydrogen bond interactions, mainly. Electrospun gelatin nanofibers showed encapsulation efficiency greater than 90% of extract and a maximum release of 95 and 80% for the medium at pH 1.5 and 7.5, respectively. Therefore, the electrospinning technique is a good alternative for the conservation of bioactive compounds present in the eggplant peel through electrospun gelatin nanofiber.

Utilisation of collagenolytic enzymes from sierra fish (Scomberomorus sierra) and jumbo squid (Dosidicus gigas) viscera to generate bioactive collagen hydrolysates from jumbo squid muscle.

Crude extracts of collagenases from jumbo squid (Dosidicus gigas) hepatopancreas and sierra fish (Scomberomorus sierra) viscera were used to hydrolyse squid muscle collagen into peptides with inhibitory capacity over angiotensin I-converting enzyme (ACE) and ABTS free radicals [2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)], as a measure of their antihypertensive potential and antioxidant activity, respectively. Proteins from 20 to 200 kDa were found in both enzyme extracts; however, in comparison to the jumbo squid extract (JSE), the extraction yield and specific activity of the enzymatic sierra fish extract (SFE) were ≈ 40% greater, suggesting the presence of enzymes with different collagenolytic activity. Moreover, the utilised collagen was obtained with a yield of 0.98 ± 0.09 g/100 g muscle from jumbo squid arms, which after an incubation with JSE and SFE generated peptides with different biological activity. However, the collagen hydrolysates from the enzymatic SFE contained a higher proportion of low-molecular-weight peptides than that obtained from JSE (15.2 and 7.9% of < 3 kDa peptides, respectively). Finally, the antioxidant potential and ACE-inhibitory activity were increased after hydrolysis, being the SFE the one that showed a greater increase of both biological activities (82.28% of ACE inhibition and 64% of ABTS inhibition).

Biochemical Characterization of a Novel α/ß-Hydrolase/FSH from the White Shrimp Litopenaeus vannamei.

(1) Background: Lipases and esterases are important enzymes that share the α/ß hydrolase fold. The activity and cellular localization are important characteristics to understand the role of such enzymes in an organism. (2) Methods: Bioinformatic and biochemical tools were used to describe a new α/ß hydrolase from a Litopenaeus vannamei transcriptome (LvFHS for Family Serine Hydrolase). (3) Results: The enzyme was obtained by heterologous overexpression in Escherichia coli and showed hydrolytic activity towards short-chain lipid substrates and high affinity to long-chain lipid substrates. Anti-LvFHS antibodies were produced in rabbit that immunodetected the LvFSH enzyme in several shrimp tissues. (4) Conclusions: The protein obtained and analyzed was an α/ß hydrolase with esterase and lipase-type activity towards long-chain substrates up to 12 carbons; its immunodetection in shrimp tissues suggests that it has an intracellular localization, and predicted roles in energy mobilization and signal transduction.

Partial Characterization of a Low-Molecular-Mass Fraction with Cryoprotectant Activity from Jumbo Squid (Dosidicus gigas) Mantle Muscle.

Freezing conditions affect fish muscle protein functionality due to its denaturation/aggregation. However, jumbo squid (Dosidicus gigas) muscle protein functionality remains stable even after freezing, probably due to the presence of low-molecular-mass compounds (LMMC) as cryoprotectants. Thus, water-soluble LMMC (<1 kDa) fraction obtained from jumbo squid muscle was evaluated by Fourier transform infrared spectrometry. From its spectra, total carbohydrates, free monosaccharides, free amino acids and ammonium chloride were determined. Cryoprotectant capacity and protein cryostability conferred by LMMC were investigated by differential scanning calorimetry. Fraction partial characterization showed that the main components are free amino acids (18.84 mg/g), carbohydrates (67.1 µg/mg) such as monosaccharides (51.1 µg/mg of glucose, fucose and arabinose in total) and ammonium chloride (220.4 µg/mg). Arginine, sarcosine and taurine were the main amino acids in the fraction. LMMC, at the mass fraction present in jumbo squid muscle, lowered the water freezing point to -1.2 °C, inhibiting recrystallization at 0.66 °C. Significant myofibrillar protein stabilization by LMMC was observed after a freeze-thaw cycle compared to control (muscle after extraction of LMMC), proving the effectiveness on jumbo squid protein muscle cryo- stability. Osmolytes in LMMC fraction inhibited protein denaturation/aggregation and ice recrystallization, maintaining the muscle structure stable under freezing conditions. LMMC conferred protein cryostability even at the very low mass fraction in the muscle.

Effect of temperature on the actomyosin-paramyosin structure from giant squid mantle (Dosidicus gigas).

BACKGROUND: The secondary structure of a protein determines its functional properties, such as its gelling capacity. The α-helix and ß-sheet comprise its main structures. Myofibrillar proteins from jumbo squid are composed mainly of the actomyosin-paramyosin complex; this complex contains a high percentage of α-helix, because actin, paramyosin, and myosin constitute 30%, 100%, and 55% of the α-helix, respectively. It is important to elucidate the role of the secondary structures in the gelation of giant squid proteins as they form gel. The role of the secondary structures in the gelation of giant squid proteins is therefore very important. For this reason, the objective of this work was to evaluate the effect of temperature on the structural behavior of actomyosin-paramyosin isolate (API) from Dosidicus gigas. RESULTS: The unfolding of the API system, which is composed of the actomyosin-paramyosin complex, was clarified by studying surface hydrophobicity and viscosity. Three characteristic peaks were found, associated with myosin, paramyosin, and actin. Infrared and circular dichroism corroborated the view that API undergoes major structural changes, because it proceeds from mostly an α-helix structure to 100% ß-sheet. CONCLUSION: The structural rearrangement favors gelation by cross-linking, generating new protein-protein and water-protein interactions, which create a more stable structure compared to mantle proteins (MP). Likewise, the presence of sarcoplasmic and stromal proteins in D. gigas muscle prevents the unfolding of myofibrillar proteins, favoring gelation by agglomeration, decreasing the ability to trap water and thus its gelling capacity. © 2019 Society of Chemical Industry.

Refolding and Activation from Bacterial Inclusion Bodies of Trypsin I from Sardine (Sardinops sagax caerulea).

BACKGROUND: Trypsin from fish species is considered as a cold-adapted enzyme that may find potential biotechnological applications. In this work, the recombinant expression, refolding and activation of Trypsin I (TryI) from Monterey sardine (Sardinops sagax caerulea) are reported. METHODS: TryI was overexpressed in Escherichia coli BL21 as a fusion protein of trypsinogen with thioredoxin. Refolding of trypsinogen I was achieved by dialysis of bacterial inclusion bodies with a recovery of 16.32 mg per liter of Luria broth medium. RESULTS: Before activation, the trypsinogen fusion protein did not show trypsin activity. Trypsinogen I was activated by adding 0.002 U of native TryI purified from the sardine pyloric caeca (nonrecombinant). The activated recombinant trypsin showed three times more activity than the nonrecombinant trypsin alone. CONCLUSION: The described protocol allowed obtaining sufficient amounts of recombinant TryI from Monterey sardine fish for further biochemical and biophysical characterization of its coldadaptation parameters.

Evaluation of Antioxidant Capacity, Protective Effect on Human Erythrocytes and Phenolic Compound Identification in Two Varieties of Plum Fruit (Spondias spp.) by UPLC-MS.

Plum edible part was used to obtained extracts by during a 4 h maceration process using three different solvents (ethanol, methanol and water) for the determination of total phenols and flavonoids, antioxidant capacity by (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hemolysis inhibition in human blood assays. Subsequently, phenolic compounds were identified using ultra-performance liquid chromatography (UPLC-MS). The results indicated that the ethanolic extract of plum fruit being a good source of phenolic (12⁻18 mg GAE/g FW) and flavonoids (2.3⁻2.5 mg QE/g FW) content in both varieties of plum. Also, the fruits proved a good source of antioxidants as measured by DPPH and ABTS; likewise, plum aqueous extracts showed the highest protective effect on human erythrocytes with 74.34 and 64.62% for yellow and red plum, respectively. A total of 23 bioactive compounds were identified by UPLC-MS, including gallic acid, rutin, resorcinol, chlorogenic acid, catechin, and ellagic acid, and the antioxidant capacity can be attributed to these species. The edible part of plum contains compounds of biological interest, suggesting that this fruit has antioxidant potential that can be exploited for various technologies.

Nanofibers of cellulose bagasse from Agave tequilana Weber var. azul by electrospinning: preparation and characterization.

In this study, cellulose of bagasse from Agave tequilana Weber var. azul was extracted to elaborate nanofibers by the electrospinning technique. Fiber characterization was performed using Transmission Electron Microscopy (TEM), x-ray, Fournier Transform-InfraRed (FT-IR) spectroscopy, and thermal analysis by Differential Scanning Calorimetry-Thermogravimetric Analysis (DSC-TGA). Different diameters (ranging from 54.57 ±â€¯0.02 to 171 ±â€¯0.01 nm) of nanofibers were obtained. Cellulose nanofibers were analyzed by means of x-ray diffraction, where we observed a total loss of crystallinity in comparison with the cellulose, while FT-IR spectroscopy revealed that the hemicellulose and lignin present in the agave bagasse were removed. Thermal analysis showed that nanofibers exhibit enhanced thermal properties, and the zeta potential value (-32.5 mV) demonstrated moderate stability in the sample. In conclusion, the nanofibers obtained provide other alternatives-of-use for this agro-industrial residue and could have potential in various industrial applications, among these encapsulation of bioactive compounds and reinforcing material, to mention a few.

Antioxidant Peptides from Terrestrial and Aquatic Plants Against Cancer.

Cancer is the leading cause of morbidity and mortality worldwide. Therefore, the search for new and less aggressive treatments is currently the focus of the anticancer research. An attractive alternative for this purpose is the use of bioactive peptides from plants. Plants live everywhere on Earth, both on land and in water, and they are a major source of diverse molecules with pharmacological potential as antioxidant peptides. Hence, this review focuses on the importance of the antioxidant activity of terrestrial and aquatic plant peptides against cancer throughout several mechanisms. The influence of the antioxidant activity of peptides by different factors such as molecular weight and amino acid composition as a crucial factor for anticancer activity is also revised. Furthermore, the relation of antioxidant activity with anticancer property as well as safety and legal aspects of protein hydrolysates and bioactive peptides for their use in cancer treatments is discussed.

Physicochemical characterization of actomyosin-paramyosin from giant squid mantle (Dosidicus gigas).

BACKGROUND: The giant squid (Dosidicus gigas) has been proposed as raw material to obtain myofibrillar protein concentrates. However, it has been observed that colloidal systems formed from squid proteins have limited stability. Therefore, the isolation and characterization of the actomyosin-paramyosin isolated (API) complex were performed, because they are the main proteins to which functionality has been attributed. RESULTS: Densitogram analysis revealed 45% of actin, 38% of myosin and 17% of paramyosin. The amino acid profile indicates a higher proportion of acidic amino acids, which gives a higher negative charge; this was supported by the zeta potential. Total sulfhydryl (TSH) content was lower compared with proteins of other aquatic species. CONCLUSION: The higher percentage of actin in relation to myosin, the presence of paramyosin, as well as the low content of sulfhydryl groups, could comprise the main causes of the low technological functional property of proteins from D. gigas mantle. © 2017 Society of Chemical Industry.

Phenolic Compounds of Potato Peel Extracts: Their Antioxidant Activity and Protection against Human Enteric Viruses.

Potato peels (PP) contain several bioactive compounds. These compounds are known to provide human health benefits, including antioxidant and antimicrobial properties. In addition, these compounds could have effects on human enteric viruses that have not yet been reported. The objective of the present study was to evaluate the phenolic composition, antioxidant properties in the acidified ethanol extract (AEE) and water extract of PP, and the antiviral effects on the inhibition of Av-05 and MS2 bacteriophages, which were used as human enteric viral surrogates. The AEE showed the highest phenolic content and antioxidant activity. Chlorogenic and caffeic acids were the major phenolic acids. In vitro analysis indicated that PP had a strong antioxidant activity. A 3 h incubation with AEE at a concentration of 5 mg/ml was needed to reduce the PFU/ml (plaque-forming unit per unit volume) of Av-05 and MS2 by 2.8 and 3.9 log10, respectively, in a dose-dependent manner. Our data suggest that PP has potential to be a source of natural antioxidants against enteric viruses.

An in vitro study of alkaline phosphatase sensitivity to mixture of aflatoxin B1 and fumonisin B1 in the hepatopancreas of coastal lagoon wild and farmed shrimp Litopenaeus vannamei.

This study aimed to establish the combined effect of aflatoxin B1 (AFB1) and fumonisin B1 (FB1) on wild Litopenaeus vannamei hepatopancreas alkaline phosphatase (AP) activity compared with that of farmed shrimp. AP activity in hepatopancreas extract was confirmed by several specific inhibitor assays. AP activity of wild shrimp was higher than that of farmed shrimp (p < 0.05). However, AP activity from both wild and farmed shrimp was inhibited when incubated with AFB1 and FB1. The greatest inhibition occurred when AP was incubated with a mixture of AFB1 and FB1. The IC50 for AFB1 on AP activity of wild and farmed shrimp hepatopancreases was 0.790 and 0.398 µg/mL, respectively. The IC50 of FB1 was 0.87 µg/mL for wild shrimp and 0.69 µg/mL for farmed shrimp. These results suggest that, at the mycotoxins concentrations used in the study, AP from farmed L. vannamei was sensitive to the presence of both mycotoxins; however, AP is more sensitive to the combination of AFB1 + FB1 suggesting a possible synergistic or potentiating inhibitory effect.

Chymotrypsin isolation from jumbo squid (Dosidicus gigas) hepatopancreas: Partial characterization and effect on muscle collagen.

Chymotrypsin was purified from jumbo squid hepatopancreas (HP) with 2.4-fold and yield 1.9%, and characterized with a molecular weight of 31 kDa, as estimated by sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE). Chymotrypsin effect over collagen extracted from the mantle, fins and arms of the jumbo squid was evaluated. The enzyme exhibited the maximum activity at pH 7 and 65°C using Suc-Ala-Ala-Pro-Phe-p-nitroanilide (SAAPNA) as a substrate and it was identified using the specific inhibitors N-tosyl-L-phenylalaninechloromethyl ketone (TPCK) and phenyl methyl sulfonyl fluoride (PMSF), showing residual activities of 6% and 0%, respectively. Furthermore, high activity was observed in the pH range of 4.0 to 8.0. Purified enzyme showed a moderate in vitro activity using muscle collagen as a substrate. Although further research is needed, the results suggest that the enzyme has a potential application where acidic or slightly alkaline conditions are needed.

Total Phenolic, Flavonoid, Tomatine, and Tomatidine Contents and Antioxidant and Antimicrobial Activities of Extracts of Tomato Plant.

The purpose of this study was to evaluate the antioxidant and antimicrobial properties of extracts of different fractions of two tomato plant cultivars. The stems, roots, leaves, and whole-plant fractions were evaluated. Tomatine and tomatidine were identified by HPLC-DAD. The leaf extracts from the two varieties showed the highest flavonoids, chlorophyll, carotenoids, and total phenolics contents and the highest antioxidant activity determined by DPPH, ABTS, and ORAC. A positive correlation was observed between the antioxidant capacities of the extracts and the total phenolic, flavonoid, and chlorophyll contents. The Pitenza variety extracts inhibited the growth of pathogens such as E. coli O157:H7, Salmonella Typhimurium, Staphylococcus aureus, and Listeria ivanovii, yielding inhibition halos of 8.0 to 12.9 mm in diameter and MIC values of 12.5 to 3.125 mg/mL. These results suggest that tomato plant shows well potential as sources of various bioactive compounds, antioxidants, and antimicrobials.

Quality and shelf life of the gonad of lion's paw scallop transported and stored whole in refrigeration / Qualidade e vida de prateleira da gônada do bivalve pata de leão, transportado e armazenado inteiramente em refrigeração

The effect of refrigerated 48h transport and 4 days storage on the quality and shelf life of the whole lion's paw scallop Nodipecten subnodosus gonad was evaluated. Proximal composition, adenosine 5´triphosphate (ATP) and related products, K-value, total volatile bases (TVB-N), trimethylamine (TMA-N), pH, fatty acid profile and microbiological analyses were quantified. Gonad holds a significant composition of essential fatty acids while levels of gonadal ATP were initially low; moreover, K-value of the gonad remained constant. With respect to TVB-N and TMA-N, only the former exceeded allowed limits. The pH level showed no significant variation during storage and, despite the high level of TVB-N, according to the TMA-N as well as microbiological analyses it was demonstrated innocuity after 4 days under the transportation and storage conditions utilized.

Avaliou-se o efeito do transporte em refrigeração por 48 horas e quatro dias de armazenamento sobre a qualidade e vida de prateleira da gônada do bivalve pata de leão, Nodipecten subnodosus. Determinou-se a composição centesimal, a adenosina 5'trifosfato (ATP) e afins, o índice K, bases voláteis totais (TVB-N), trimetilamina (TMA-N), pH, perfil de ácidos graxos e análise microbiológica. A Gônada apresentou uma importante composição de ácidos graxos essenciais e baixos níveis iniciais de ATP, enquanto o índice K manteve-se constante. Quanto a TVB -N e TMA- N, apenas as primeiras ultrapassaram os limites admissíveis. Os valores de pH não mostraram nenhuma mudança significativa durante o armazenamento e, apesar dos altos níveis de TVB -N, de acordo com a análise quantitativa e microbiológica TMA- N, a segurança do produto foi demonstrada após quatro dias sob as condições de transporte e armazenamento utilizado.

Chemical constitution and effect of extracts of tomato plants byproducts on the enteric viral surrogates.

Byproducts of tomato are known to include phenolic compounds but have not been studied in depth. In this study, the phenolic compositions of (stem, leaf, root, and whole plant) of two tomato cultivars, Pitenza and Floradade, were analyzed by HPLC-DAD. In parallel, the antiviral effects of crude extracts on viral surrogates, the bacteriophages MS2 and Av-05 were evaluated. The leaf extracts from the two varieties showed the highest concentration of phenolic compounds. The compounds identified were gallic acid, chlorogenic acid, ferulic acid, cafeic acid, rutin, and quercetin, and they represented 3174.3 and 1057.9 mg/100 g dried weight of the Pitenza and Floradade cultivars, respectively. MS2 and Av-05 titers at 5 mg/mL were reduced by 3.47 and 5.78 log10 PFU/mL and 3.78 and 4.93 log10 PFU/mL by Pitenza and Floradade cultivar leaf extract, respectively. These results show that tomato extracts are natural sources of bioactive substances with antiviral activity.

Jumbo squid (Dosidicus gigas) mantle collagen: extraction, characterization, and potential application in the preparation of chitosan-collagen biofilms.

Collagen-based biomaterials have been widely used due to its binding capabilities. However the properties and potential use of new collagen sources are still under investigation. Fish by-products are an excellent source of collagen. Thus, acid-soluble collagen (ASC) was extracted, and biochemical and physicochemically characterized from one under-utilized specie, jumbo squid (Dosidicus gigas). In addition, commercial chitosan (95-50%)-ASC (5-50%) blend films were successfully prepared by casting, and characterized by infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The molecular masses of the ASC subunits were about 190kDa, 110kDa, and 97kDa, the content of proline and hydroxyproline was 10.9% and 2.8%, respectively. The FT-IR and nuclear magnetic resonance spectra ((1)H NMR) confirmed collagen peptidic crosslinks, and one endothermic peak was found at 119 degrees C. The FT-IR spectrum showed that chitosan and ASC remain linked into the films mainly due to hydrogen bonding. The 85:15 (chitosan:ASC) ratio was selected for its thermal and mechanical analyses. The thermograms of this film indicated the presence of two peaks, one at 87-98 degrees C and the other at 142-182 degrees C. The chitosan:ASC blend produced a transparent and brittle film, with high percentage of elongation at break, and low tensile strength in comparison to chitosan films. D. gigas mantle might be useful as a new source of plasticizer agent in the preparation of biofilms in composites with chitosan.

Efecto de la concentración de quitosano y ph sobre la remoción de sólidos en agua de cola de la industria sardinera / Effect of chitosan concentration and ph on the removal of solids from stickwater produced in the sardine industry / Efeito da concentração de quitosana e ph sobre la remoção de sólidos em resíduos líquidos da indústria de sardinhas

El agua de cola es un efluente complejo compuesto por una gran variedad de sólidos, los cuales deben ser removidos en su mayor parte para generar un efluente que pueda ser vertido directamente al mar. En el presente estudio el agua de cola se centrifugó y posteriormente se trató con quitosano a distintos valores de pH y concentraciones con la finalidad de remover sólidos presentes. Mediante la centrifugación se logró remover el 33,88% de los sólidos totales; 28,52% de proteína; 97,50% de grasa; 40% de ceniza y 20% de NNP, y disminuyeron la DBO5 y la DQO en un 42,2 y 63,3% respectivamente. El porcentaje de transmitancia aumentó de 14,6 a 18,4 siendo éste un cambio pequeño en relación al contenido de sólidos removido. La adición de quitosano al agua de cola centrifugada redujo en 25% el contenido de sólidos totales, 55% el de proteína, 40% el de grasa, 24% el de cenizas y 60% el de NNP. De igual forma, disminuyó la DBO5 y la DQO en un 48,4 y 31,2% respectivamente. Como resultado de la adición el porcentaje de transmitancia aumentó de 18,4 a 86,0; indicando que tal aumento se debió principalmente a la remoción de pigmentos y no de materia orgánica. Se logró una disminución importante en DBO5 y DQO; sin embargo, se requieren otras herramientas para reducir estos valores a concentraciones establecidas en la reglamentación sanitaria.

The stickwater is a complex effluent consisting of a variety of solids, most of which should be removed to produce a new effluent that can be directly poured into the sea. In this study, stickwater was centrifuged to remove solids and the resulting liquid was then treated with chitosan at different concentrations and pH to eliminate the solids left in it. Centrifugation extracted 33.88% of total solids, 28.52% protein, 97.50% fat, 40% ash and 20% NPN. It also decreased in 42.2 and 63.3% the BOD5 and COD, respectively. Transmittance percent increased from 14.6 to 18.4, a small change in relation to the content of solids removed. The addition of chitosan to centrifuged stickwater decreased 25% of the total solids content, 55% of protein, 40% fat, 24% ash and 60% NPN. Likewise, the addition of chitosan decreased the BOD5 and COD in 48.4 and 31.2%, respectively. As a consequence, transmittance increased from 18.4 to 86.0%, indicating that such increase was mainly due to the elimination of pigments rather than organic matter. A significant decrease was achieved in BOD5 and COD; nevertheless, other tools are required to reduce these figures to the levels established by the environmental health regulations.

O residuo liquido (stickwater) é un efluente complexo composto por uma grande variedade de sólidos, os quais deven ser removidos principalmente para gerar un efluente que possa ser vertido diretamente ao mar. No presente estudo o residuo líquido foi centrifugado e posteriormente tratado com quitosana a distintos valores de pH e concentrações com a finalidade de remover sólidos presentes. Mediante a centrifugación se conseguiu remover 33,88% dos sólidos totais; 28,52% de proteína; 97,50% de gordura; 40% de cinza e 20% de NNP, e diminuiram a DBO5 e a DQO em 42,2 e 63,3% respectivamente. A porcentagem de transmitância aumentou de 14,6 a 18,4 sendo esta uma mudança pequena em relação ao conteúdo de sólidos removido. A adição de quitosana no residuo líquido centrifugado reduziu em 25% o conteúdo de sólidos totais, 55% o de proteína, 40% o de gordura, 24% o de cinzas e 60% o de NNP. De igual forma, diminuiu a DBO e a DQO em 48,4 y 31,2% respectivamente. Como resultado da adição, a porcentagem de transmitância aumentou de 18,4 a 86,0; indicando que tal aumento foi devido principalmente à remoção de pigmentos e não de matéria orgânica. Alcançou-se uma diminuição importante em DBO5 e DQO; no entanto, são requeridas outras ferramentas para reduzir estes valores a concentrações estabelecidas na regulamentação sanitária.