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Cheese whey (CW) is the liquid by-product of cheese and yogurt making. This potential pollutant has high-quality nutrients exploitable through fermentation processes. Using high-intensity ultrasound on dairy products has shown several technological advantages for bioprocesses. Therefore, this study aimed to investigate the effect of high-intensity ultrasound (HIUS) on kefir grains biomass increase and specific metabolites in CW kefir. Fresh CW was ultrasonicated at 9.0 ± 2.7 and 18.0 ± 3.0 W/cm2 for 30 and 180 s, inoculated with kefir grains, and fermented for 40 h. Total exopolysaccharide production, kefir grains biomass increase, titratable acidity, pH, and soluble solids were analyzed every 8 h. CW pretreated with 18.0 ± 3.0 W/cm2 for 180 s and fermented for 16 h had significantly higher (p < 0.05) total exopolysaccharide concentration than the control: 212.7 ± 0.0 and 186.6 ± 0.0 mg/L, respectively. Ultrasonicated CW at 18 W/cm2 for 30 and 180 s at 24 h fermentation time had significantly higher kefir grains biomass (p < 0.05) than the control: 44.2 ± 0.8 and 43.6 ± 0.9 g/L, and 40.5 ± 0.4 g/L, respectively. Fresh CW pretreated with HIUS enhanced the biosynthesis of kefir beverage total exopolysaccharides concentration and kefir grains biomass.

Fishing products are characterized for being highly perishable; therefore, preservation methods are used to retain freshness and quality and extend shelf life. One of the factors that most impact the loss of freshness, quality, and shelf life is storage temperature. This study evaluated the effect of storage temperature (0 ºC and 5 °C) on the quality and shelf life of tilapia (Oreochromis niloticus) muscle during 20 days of storage. Adenosine 5’-triphosphate (ATP) and related compounds, K-value, pH, color, texture, water holding capacity (WHC), total volatile bases (TVB-N), and total count of mesophilic microorganisms were monitored. Both time and storage temperature had a significant effect (P < 0.05) on the K-value, TVB-N, and total count of mesophilic microorganisms. The overall results of this study indicated that the edible quality of tilapia muscle was affected by storage temperature, observing a shelf life of 16 days at 0°C and 8 days at 5 ºC.

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

Se realizó la microencapsulación por coacervación compleja de extractos de higo en tres etapas de madurez, utilizando dos complejos: Proteína de Soya Aislada con Goma Arábiga (SPI/GA) y Gelatina con Goma Arábiga (G/GA) como material de pared. La estabilidad de las cápsulas se evalúo en términos de la presencia de compuestos fenólicos, la actividad antioxidante mediante las técnicas de ABTS y bioensayo de hemólisis. El rendimiento fue mayor en el complejo de G/GA, con valores superiores al 60 %. Este complejo también logró una mejor formación de perlas de acuerdo a su morfología. Ambos complejos (SPI/GA y G/GA) mostraron estabilidad en términos de capacidad antioxidante, por lo tanto, el proceso de coacervación compleja es una técnica capaz de retener los compuestos fenólicos presentes en el higo.ABSTRACTMicroencapsulation was performed by complex coacervation of fig’s extracts in three stages of maturity, using two complexes: isolated soy protein with arabic gum (ISP/AG) and gelatin with arabic gum (G/ AG) as wall material. The stability of the capsules was evaluated in terms of the presence of phenolic compounds, the antioxidant activity using the techniques by ABTS and hemolysis bioassay. In addition, we obtained the yield percentage and morphology of the microcapsules. The yield was higher in the G/AG complex, with values greater than 60 %. This complex also has a better pearl formation according to its morphology. Both complexes (G/AG. ISP/AG and G/AG) have stability in terms of antioxidant capacity; therefore, the complex coacervation process is a technique capable to retain phenolic compounds present in fig.

El objetivo de la presente investigación fue evaluar el efecto de la temperatura de almacenamiento (0 y 5ºC) sobre los principales metabolitos y parámetros relacionados con el rigor mortis del músculo de tilapia (Oreochromis niloticus). Se evaluó el índice de rigor (IR), adenosina 5´-trifosfato (ATP), glucógeno, ácido láctico, pH y textura. El análisis del IR se realizó durante 266 h de almacenamiento a las dos temperaturas, mientras que el resto de los parámetros se monitorearon al tiempo 0 y a las 48 h de almacenamiento en ambas temperaturas. Se encontró que tanto la temperatura como el tiempo de almacenamiento presentaron un efecto significativo sobre el IR, siendo más pronunciado a 5°C en comparación al de 0°C.ABSTRACTThe aim of this research was to evaluate the effect of storage temperature (0 and 5°C) on the main metabolites and related parameters to rigor mortis in muscle of tilapia (Oreochromis niloticus). The rigor index (IR), adenosine 5’-triphosphate (ATP), glycogen, lactic acid, pH and texture were evaluated. The IR analysis was performed during 266 hours of storage at the two temperatures, while the rest of the parameters were monitored at 0 and at 48 hours of storage at both temperatures. It was found that both temperature and storage time, had a significant effect on IR, being more pronounced at 5°C compared to 0°C.

El presente trabajo de investigación determinó el efecto de la temperatura estable y oscilante del agua de mar a tres diferentes niveles (21, 24 y 28°C), sobre la condición fisiológica de la almeja mano de león Nodipecten subnodosus. Para ello, se evaluaron los siguientes indicadores fisiológicos: contenido de adenosina trifosfato (ATP), glucógeno y carbohidratos totales, así como índice de rendimiento muscular (IRM) y carga energética adenilada (CEA), los cuales se determinaron en el músculo abductor de organismos extraídos directamente de la laguna y después de la aplicación de los tratamientos. Se encontró que, en el experimento, las concentraciones de ATP, contenido de glucógeno, carbohidratos totales, e IRM disminuyeron significantemente (P

Horticultural products disinfection with short wave ultraviolet light (UV-C) depends mainly on dose. This parameter is defined as the product between time and intensity radiation. In general, short doses cause beneficial or hormetic effects, such as decrease of microbial load and fruits and vegetables quality preservation. While UV-C light high doses or long exposure times generate changes in those products, such as enzymatic browning, loss of texture, among others, which cause a decrease in shelf life and functional properties. Therefore, this article presents the most cited techniques to determine doses in horticultural products, some experimental and others that employ microbiology and mathematical knowledge, radiochromic films and computational fluid dynamics (CFD). The review highlights that CFD allow the development of simulations in real environments, quickly and economically, including radiation models prone to experimental validation and help to improve the arrengement of horticultural products in the equipment to achieve a uniform irradiation.ABSTRACTLa desinfección de productos hortofrutícolas con luz ultravioleta de onda corta (UV-C) depende principalmente de la dosis. Este parámetro se define como el producto entre el tiempo e intensidad de radiación. En general, las dosis cortas ocasionan efectos benéficos u horméticos, tales como la disminución de carga microbiana y preservación de la calidad de las frutas y hortalizas durante su vida útil. Mientras que las dosis altas o los largos tiempos de exposición a la luz UV-C generan cambios en dichos productos, tales como el oscurecimiento enzimático, pérdida de textura, entre otros, los cuales provocan una disminución de la vida útil y la pérdida de las propiedades funcionales. Por lo tanto, este artículo presenta las técnicas más citadas para determinar las dosis en productos hortofrutícolas, algunas de carácter experimental y otras que emplean conocimientos de microbiología y matemáticas, películas radiocrómicas y la dinámica de fluidos computacional (CFD). La revisión destaca que la CFD permite el desarrollo de simulaciones en entornos reales de forma rápida y económica, comprende modelos de radiación que pueden ser validados de forma experimental y ayuda a mejorar la disposición de los productos hortofrutícolas en el equipo para lograr una irradiación más uniforme.

BACKGROUND: The secondary structure of a protein determines its functional properties, such as its gelling capacity. The α‐helix and β‐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% β‐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

The aim of this study was to evaluate the effects of chitosan-tomato plant extract (C-TPE) edible coating (EC) applications on the physicochemical, microbiological, sensory and antioxidant capacity of chicken during storage. Edible coatings prepared with chitosan 1%, acetic acid 1%, glycerol and TPE (0.1 and 0.3%) were tested. The slices were submerged for 1 minute in different treatments (T1: C 1%; T2: C 1% + TPE 0.1%; T3: C 1% + TPE 0.3%; T4: control) and stored at 4 °C. At the end of the storage period, the treatments exhibited the greatest physicochemical and microbiological effects in the slices, reducing the microbial population relative to the control. The T2 treatment exhibited the highest antioxidant capacity, total phenolic content and overall acceptance. The results demonstrate that the application of C with the addition of a natural extract, such as those from the tomato plant, can be an alternative method for preserving chicken meat.

Physicochemical and structural properties of soluble jumbo squid (Dosidicus gigas) elastin recovered from skin by-products were evaluated. The molecular weight of isolated elastin was ~40 k...

The giant squid (Dosidicus gigas) might be used as a raw material for a protein concentrate. However, it has been observed that colloidal systems formed from squid proteins have limited functionality. Therefore, several investigations have been done to improve the functional properties of squid proteins. Recently ultrasound has been considered a technology for improving the functional properties of proteins. For this reason and considering that jumbo squid is an important fishery in northwest Mexico, the purpose of this research was to determine the effect of sonication time on the main functional properties of proteins. Sonication at 20 kHz and 20% amplitude were used during 0, 30, 60, and 90 s for foam and emulsion evaluations, and for 0, 1, and 3 min to evaluate gelling capacity. The emulsifying activity index was the highest at 60 s, while the emulsion stability index was the best at 90 s. Foaming capacity was significantly higher at 60 and 90 s, while the foam stability was 100% for all treatments. Finally, the water holding capacity and the texture profile analysis of gels showed an improvement.

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 (

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

This research studies the application of ultrasound (US) on sarcoplasmic proteins from giant squid (Dosidicus gigas) mantle and its effect on its functional properties. US was applied during 30, 60 and 90 s. A decrease was observed in the emulsifying activity index (EAI), an increase in the emulsifying stability index (ESI), an increase in the foaming capacity (FC) and a decrease in the foaming stability (FS). In addition, the application of US increased the surface hydrophobicity (So) and decreased the viscosity with the increase in temperature. Functional properties of sarcoplasmic giant squid mantle proteins increase with the application of ultrasound.

Navicula incerta is a benthic diatom with potential use in nutrition and health for humans and aquaculture. Therefore, it is important to know its optimal growth conditions and biochemical composition. In this study, the effects of nitrate and silicate concentration on the growth kinetics and biochemical composition of N. incerta under laboratory conditions were measured. F/2 media was used as the control, and different concentrations of nitrogen (N/4, N/8 and N/16) and silicates (Si/4, Si/8 and Si/16) were evaluated. We measured cell concentration, chlorophyll-a and conducted proximal chemical analyses. It was found that different concentrations of nutrients affected the diatom’s growth kinetics and affected the concentrations of ash, chlorophyll, protein, lipids and carbohydrates. The highest concentration of lipids was obtained in the limiting treatment of nitrogen N/8 (27.09%), while the lowest value was found with silicate Si/8 media (16.97%). Carbohydrates increased compared to the control, with the N/16 treatment presenting the maximal concentration (23.31%). Treatments with reduced nitrate (N/8 and N/16) demonstrated the lowest concentrations of protein (18.75 and 12.44%, respectively), while in reduced silicate treatments, no statistical differences (P ≥ 0.05) were observed. Therefore, media limited nitrogen and silicates affected the growth kinetics and proximal chemical composition of N. incerta. The growth of this species using the N/8 medium is a suitable method for increasing lipid concentration in N. incerta.

In recent years it has been pointed out that the feed of farmed fish has an effect on the quality of the final product. Therefore, this study evaluated the effect of fishmeal (FM) replacement by a mixture of plant protein (MPP) on the development of rigor mortis of tilapia (Oreochromis niloticus). One hundred and twenty fish at an initial average weight of 123 ± 6.3 g were fed with three extruded isonitrogenous and isolipidic 6.2% crude lipids experimental diets, in which FM were replaced by 0% (D0), 50% (D50), and 100% (D100) of MPP (soybean meal, corn meal, wheat meal, and sorghum meal). A reference diet (DC) containing FM as the main protein source was used as a control. The fish were divided into triplicate groups per dietary treatment. The experiment was conducted in a tank system at 26.8°C water temperature for 67 days. The chemical composition of experimental diets and muscle were determined. The glycogen, adenosine 5′-triphosphate (ATP) and related compounds, pH, shear force, and rigor index (RI%) were monitored during storage on ice for 48 h. The results indicated that FM replacement affected (p≤0.05) the muscle composition, where the fish fed with D100 presented the higher content of lipids and ash. Fish fed with D0 and DC presented a more pronounced onset of rigor mortis and also showed a higher IR%, a lower content of glycogen, ATP, adenosine 5′-diphosphate (ADP), adenosine 5′-monophosphate (AMP), pH, and shear force. The changes in chemical composition of muscle and other parameters evaluated indicated that FM replacement increases energy reserves (glycogen, ATP, ADP, and AMP) which delayed the onset of rigor mortis, as well as a lower pH and shear force in the muscle of tilapia. Therefore, the substitution of FM by MPP could contribute to delaying the onset of rigor mortis and with this, the quality and shelf life of tilapia could be increased.

Se evaluó el efecto de las enzimas de vísceras de sardina Monterey en el tratamiento del agua de cola producida por sardinas crinuda y Monterey y, se compararon con enzimas de un extracto comercial. Además, se aplicó una centrifugación complementaria al ensayo. La enzima comercial tuvo mayor actividad proteasa que la enzima de víscera de sardina (0.65 U/mg vs. 0.35 U/mg) y que la actividad colagenasa (0.022 Hyp/mg/min vs. 0.0102 Hyp/mg/min). Se observaron grados de hidrolisis mayores sobre agua de cola de sardina crinuda (16.1 %), y no se registraron diferencias significativas (P≥0.05) en el agua de cola de sardina Monterey por el uso de las enzimas de vísceras de sardina Monterey y enzimas comercial. Se obtuvo mayor hidrolisis al aplicar la enzima de víscera de sardina Monterey sobre el agua de cola centrifugada (57.1 % vs. 17.4 %) sin importar la especie de sardina utilizada. La enzima comercial disminuyó la viscosidad sobre el agua de cola, mientras que la enzima de víscera de sardina Monterey lo hizo sobre el agua de cola centrifugada. La electroforesis mostró una disminución de la fracción PM>220 kDa en el agua de cola. Lo anterior, indicó que la enzima comercial tuvo una mayor actividad sobre agua de cola, mientras que la enzima de víscera de sardina Monterey lo tuvo en agua de cola centrifugada, sin importar el tipo de sardina utilizada para la elaboración del agua de cola.

The aim of this study was to evaluate the effectiveness of chitosan&ndash, tomato plant extract (C-TPE) edible coating (EC) on the physicochemical, microbiological, sensory, and antioxidant capacity changes of pork during storage. Edible coatings prepared with chitosan 1%, acetic acid 1%, glycerol, and TPE (0.1% and 0.3%) were tested. Slices of pork were submerged in different treatments (T1: C 1%, T2: C 1% + TPE 0.1%, T3: C 1% + TPE 0.3%, T4: control) and stored at 4 &deg, C. The different treatments showed the best results in physicochemical and microbiological analyses, with reduced microbial population relative to the control. The highest antioxidant capacity and total phenolic content were shown in T3, and the overall acceptance was better in T2. The results show that the application of C with the addition of natural extracts, such as the tomato plant with antioxidant and antimicrobial properties, can be an alternative method for preserving pork.

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 ± 0.02 to 171 ± 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.

Se evaluó el efecto de la centrifugación complementaria en la composición química y reológica parcial, así como la biodegradabilidad del agua de cola de sardinas Monterey y sardina crinuda como alternativa en la recuperación de sólidos. Se utilizó agua de cola y se centrifugó para posteriormente aplicarle los análisis respectivos. Es de resaltar que la centrifugación complementaria reduce significativamente la concentración de sólidos totales, viscosidad, demanda bioquímica de oxígeno (DBO5) y demanda química de oxígeno (DQO) a valores cercanos al 50 %. La concentración de colágeno en el agua de cola (11.7 mg/g y 3 mg/g) fue más alta que las observadas después de centrifugar (3.3 y 0.87 mg/g), además, la viscosidad presentó una relación con la concentración de colágeno/gelatina, que ayuda a calcular la biodegradabilidad. Esta, se calculó mayor de 2.5 pero menor de 5. Se concluye que la centrifugación complementaria como operación unitaria aumenta la recuperación de sólidos y mejora del tratamiento agua de cola.

Se evaluó el efecto de tres niveles de sustitución de proteínas de origen animal por vegetal sobre la condición fisiológica de la tilapia del Nilo Oreochromis niloticus. Para ello, se formularon alimentos experimentales con 0, 50 y 100% sustitución de proteína animal por proteína vegetal. Los alimentos tuvieron un 37% de proteína y un contenido calórico de 17.6 kJ/g. Para la sustitución se utilizó una mezcla de harinas de soya, trigo, maíz y sorgo. El efecto de los alimentos se evaluó en un bioensayo de 60 días, suministrando diariamente los alimentos a las 09:00, 13:00 y 17:00h. Para evaluar la condición fisiológica se cuantificó la concentración de ATP, carbohidratos totales, glucógeno y pH del tejido muscular. Asimismo, se calculó la carga energética adenilada (AEC) y se determinó la composición química de las dietas experimentales y del músculo. Los resultados obtenidos indicaron que los niveles de sustitución de proteína de origen animal por proteína de origen vegetal, no afectaron (P

Optimal usage of urea-based fertilizers can increase their use efficiency and reduce pollution. A new alternative for prolonged-release (PR) urea based on wheat-gluten (WG) membranes obtained by electrospinning was studied. The effect of pH and temperature on the release rate of urea and its transport mechanisms were evaluated. At pH 4, 7, and 10, the equilibration times obtained were 1, 3, and 5 h, respectively. Additionally, at a higher temperature, a larger amount of urea was released into the medium. The Ritger–Peppas model suggests that with pH 4 and pH 10, at 25 °C, there is an anomalous diffusion mechanism. On the other hand, the remainder of the release conditions tested showed a release mechanism of urea by simple diffusion. According to the results, a potential application of these wheat-gluten membranes on the release system of urea for soils with pH 7 and soil temperatures between 25 and 40 °C is proposed.

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.

Collagen is the major connective tissue (CT) protein and one of the main constituents of the jumbo squid (Dosidicus gigas). Therefore, physicochemical changes of pepsin-solubilized collagen (PSC) and insoluble collagen (IC) were studied after cooking (100°C/30 min) of muscle (mantle, fins, and arms). Different pyridinoline (Pyr) contents (the major cross-linking molecule in collagen fibers) were found in the fresh muscle of the three anatomical regions. After the cooking process, a decrease from 10 to 30% in the thermal resistance of collagen was observed, depending on the anatomical region and fraction evaluated. Furthermore, the electrophoretic profile, Fourier transform infrared (FTIR) spectroscopy, and the amino-acid profile revealed that structural changes occurred in the two different collagen fractions caused by the thermal process, and the changes were greater in the mantle. Under the conditions applied in this study, collagen fractions from the squid arms showed more stability during the cooking process due to the high cross-linking degree of their fibers.

The chemical structure, thermal denaturation and nanostructure of collagen, obtained from a cation-exchange separation of the mantle, fins and tentacles of jumbo squid (Dosidicus gigas), were comparatively studied. The main idea of this work, was to provide an in-depth understanding of the interdependence between pyridinoline (Pyr) content, helix chemical structure and nanostructure of squid collagen with squid tissue firmness. The tentacles required more shear force and its collagen presented the higher temperature and enthalpy of transition, than the mantle and fins. The tentacle firmness may be explained by the relatively higher imino amino acid content, proline and lysine hydroxylation degrees and Pyr content of its collagen. Moreover, among the regions studied, the collagen from the tentacles had a more intense β band chain. Also, the Fourier transform infrared analysis and Raman spectra, implied that the collagen in the tentacles, was more intermolecularly ordered than the mantle and fins. Consistent with these results, a comparative evaluation of the surface morphology of the three regions, with atomic force microscopy, suggested a more ordered collagen structure in the tentacles (lower roughness values). Based on the above, collagen from tentacles has a higher degree of molecular order that sustains a higher muscle firmness compared to that of other anatomical regions.

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.; © 2017 Society of Chemical Industry.

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.

Chitosan films (CF) [1 and 2% w/v] alone and with cinnamaldehyde (CNE) [0.25, 0.5 and 1% v/v] were prepared using an emulsion method, and the obtained films were characterized in terms of water vapor permeability (WVP), water solubility and optical, mechanical and antioxidant properties. The incorporation of CNE at 1% (v/v) significantly decreased the water solubility of the film by approximately 4% for the 1 and 2% CF films, whereas the WVP increased (2.5–3.5 times). The incorporation of CNE (0.25 and 0.5%) into 2% CF significantly increased the tensile strength (TS) (62 and 34%, respectively) and the percent elongation (%E) values, 26, 30 and 52% for CF that contained 0.25, 0.5 and 1% CNE, respectively. The largest value of the elasticity modulus (EM) was observed for 2% CF with 0.25% CNE. All films exhibited a yellow appearance (b*), but the CNE content had a marked impact on the coloration of the films. The CNE recoveries of the CF films (1 and 2%) with 1% of CNE were high (43 and 67%). The antioxidant activities indicated that the incorporation of 1% CNE into CF films (1 and 2%) increased the antioxidant activity. The protective effects of the films with and without CNE on erythrocytes were very strong (36–72% hemolysis inhibition). These results suggest there are potential applications for CF-CNE films as active packaging for the preservation of food products.

Chemical–structural properties and crosslinking degree (lysyl oxidase [Lox] enzymatic activity and pyridinoline [Pyr] content) of collagen isolated from the muscle of octopus (Octopus vulgaris), guitarfish (Rhinobatos productus), and cazon (Mustelus lunulatus) are reported and related with the muscle texture. Histological analysis revealed more collagen fibers stained in the tissues from octopus, which also showed greater shear force (SF) (191.9 ± 38.2 N) compared with the guitarfish (19.7 ± 5.3 N) and cazon (26.2 ± 14.3 N) muscle. The extent of cross‐linked collagen decreased in the order: octopus > guitarfish > cazon. An increase in the total enzymatic activity of the Lox, Pyr content, and insoluble collagen (IC) extraction yield matched with an increase in the SF (p

(1) Background: Lipases and esterases are important enzymes that share the &alpha, /&beta, 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 &alpha, 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 &alpha, 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.

Conventional plastic materials accumulation has led to a constant search to develop friendly packaging, edible coatings from biopolymers are an example. Since different proteins have different behavior and plastizicer compatibility, in this work, the effect of different polyalcohols (glycerol, sorbitol, maltitol, mannitol, and xylitol) as plasticizers on squid protein films behavior was studied. The results show that except for mannitol, transparent, and flexible films can be obtained. None of them showed transmission to light on the ultraviolet (UV) spectrum. However, only glycerol and sorbitol were sufficiently flexible to evaluate their mechanical properties, in which glycerol had a more elastic behavior with an elongation at a break of 920% and tensile strength (TS) of 0.94 MPa, while sorbitol exhibited a more plastic behavior with an elongation at break of 511% and a TS of 4.41 MPa. Water-vapor transmission rate was higher in glycerol, with 194.41 g&middot, m&minus, 2d&minus, 1, while sorbitol had 44.27 g&middot, 1 but presented blooming. This could be due to low interaction between sorbitol and the protein matrix, correlating with the film-solubility results. Amide I band of the Fourier transform infrared (FT-IR) spectra demonstrated higher denaturation and loss of alpha helical structure in glycerol film, followed by maltitol/sorbitol, xylitol, mannitol, and the control film. This in accordance with thermogravimetric analysis (TGA) results. The results of this study prove that only glycerol and sorbitol are suitable to obtain a see-through flexible film.

The present study was accomplished to gain insights into the biochemical and kinetic properties of Rhyzopertha dominica’s α-amylase isoforms (named RdA70, RdA79, and RdA90) expressed in progenies reared in wheat varieties differing in α-amylase inhibitory activity. An inverse relationship was observed between the progenies’ amylase activity and the wheat inhibitory activity. Wheat samples with a high and low infestation (named HI-Borlaug and LI-Villa Juarez, respectively) were chosen to simplify the study. The progenies amylases were isolated by hydrophobic interaction chromatography, while the wheat samples were analyzed in α-amylase inhibitory activity by size exclusion chromatography. The isoforms RdA70 and RdA90 from LI-Villa Juarez progeny showed higher enzyme activities (73.8 and 43.4%, respectively) than those from HI-Borlaug. When the amylase isoforms were tested in susceptibility to inhibition by the inhibitory albumins, those from LI-Villa Juarez were more susceptible than those of the HI-Borlaug. Determination of the kinetic parameters revealed that RdA70 from the HI-Borlaug progeny showed 3.0-fold less starch affinity than that from the LI-Villa Juarez (Km of 12.3 ± 1.8 versus 4.0 ± 0.3). The rest of the α-amylases did not show the same pattern as RdA70 in the HI-Bourlag as that their starch affinity was further reduced (RdA79 Km = 23.1 ± 4.3, RdA90 Km = 17.1 ± 2.9). Estimation of IC50 values confirmed the high sensitivity of the three α-amylases of the LI-Villa Juarez progeny to wheat α-amylase inhibitors. The inhibitor constant Ki was the lowest for RdA70 in the LI-Villa Juarez progeny indicating the inhibitor’ tight binding to that isoenzyme. These results suggest that R. dominica uses RdA70 to bind large amounts of wheat α-amylase inhibitors than RdA79 and RdA90 as a physiological defense mechanism.

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.