Nanoencapsulation of Maqui (Aristotelia chilensis) Extract in Chitosan-Tripolyphosphate and Chenopodin-Based Systems.

Maqui berries contain a high percentage of anthocyanins with high antioxidant and anti-inflammatory capacity but that are unstable in the colonic site. Nanocarriers based on polysaccharides and/or proteins can protect against the degradation of anthocyanins. The aim of this study was the nanoencapsulation of maqui extract (ME) in chitosan-tripolyphosphate (CTPP-ME), chenopodin (CH-ME), and chenopodin-alginate (CHA-ME). A standardised ME was prepared and then encapsulated in the nanosystems. The physicochemical properties, encapsulation parameters, and the interactions of ME with the nanovehicles were characterised. The cyanidin-3-glucoside released and ORAC activity in phosphate buffer at pH 7.4 were evaluated. The content of ME was 8-9 mg of cyanidin-3-glucoside/g of extract. CTPP with ME at 3% obtained the highest encapsulation efficiency (EE = 91%), and no significant differences were observed in size (274-362 nm), PDI (0.5-0.7), and zeta potential (+34-+41 mV) when the concentration of ME changed from 1% to 5%. CH-ME was shown to be smaller (152 nm) than CTPP-ME, and CH-ME and CHA-ME showed lower EE (79% and 54%, respectively) than CTPP-ME. FT-IR revealed a stronger interaction of ME with CTPP-ME than with CH-ME. Both systems showed a significantly lower release than free ME, and the T50 value of CTPP-ME 3% (328 min) was higher than CH-ME (197 min). Both protected the ORAC activity of ME.

Development of a scalable procedure by a discontinuous crossflow DF/UF to obtain a concentrate of chenopodin from a dead-end centrifugal UF at bench scale.

The aim of this study was to develop a scalable crossflow diafiltration/ultrafiltration procedure for quinoa 11S globulin purification starting at the bench scale using Ultra15 centrifugal filter devices. The electrophoretic profiles of centrifugal ultrafiltration fractions showed a high heterogeneity in the bands, while crossflow ultrafiltration reduced the phenomena of protein sticking to the membrane, avoiding aggregate formation. In the crossflow protein concentration, flux decline curves were studied according to Hermia's fouling mechanisms and the resistance in a series model. High reversible resistance was related to external mechanisms due to complete blockage of the membrane surface followed by cake formation. The crossflow ultrafiltration was the most efficient technique for obtaining 57 kDa chenopodin isolate with higher processing capacity, purity and protein yield. The diafiltration/ultrafiltration process proved to be adequate and easy to handle to scale up the production of the 11S quinoa globulin.

Soluble complexes between chenopodins and alginate/chitosan: Intermolecular interactions and structural-physicochemical properties.

The research aim was to study the nature of intermolecular interactions involved in the formation of soluble complexes between chenopodins (QP) and anionic/cationic polysaccharides, sodium alginate (Alg) and chitosan (CH), above the pI of QP at different protein-polysaccharide ratios; and to evaluate their structural-physicochemical properties. The interactions and properties analysed by electrical conductivity, zeta potential, hydrodynamic particle size, intrinsic and extrinsic fluorescence spectroscopy, circular dichroism spectroscopy, differential scanning calorimetry and infrared spectroscopy. The protein-polysaccharide ratio and the type of polysaccharide influenced the complexes properties. In QP-CH complexes, the main interactions were electrostatic, while in QP-Alg complexes, hydrophobic interactions, hydrogen bonds and weak electrostatic interactions were detected. Changes in secondary and tertiary structure and increased thermal stability of chenopodins in the presence of both polysaccharides were observed. QP-Alg and QP-CH complexes seemed to have achieved the strongest interactions at 1:4, 2:3 and 3:2 ratios and at 1:4 and 2:3 ratios, respectively.

Effect of high-intensity ultrasound treatment in combination with transglutaminase and nanoparticles on structural, mechanical, and physicochemical properties of quinoa proteins/chitosan edible films.

The effect of high-intensity ultrasound (US) combined with transglutaminase treatment (TG) and the inclusion of nanoparticles (Np) on the structural, mechanical, barrier, and physicochemical properties of quinoa protein/chitosan composite edible films were evaluated. Structurally it was observed that the maximum temperatures of the thermal degradation increased with the use of combined US and TG treatment, generating films with superior thermal stability. FTIR results showed that in the amide zone I oscillations of the polypeptide structure were related to the stretching vibrations of CO in the US/TG-Np edible film. Which has generally been associated with changes in the structure and formation of covalent bonds by the action of TG. The US improved mechanical properties by increasing the tensile strength (with or without the application of TG). While combining US-TG produced a significant increase in thickness, decrease in elongation percentage, and increase in tensile strength. Which can be attributed to cross-linking produced by TG. Water vapour permeability increased in all cases. In general, the combination of US-TG treatments showed a more pronounced effect on the structure and mechanical properties.

Thymol nanoemulsions incorporated in quinoa protein/chitosan edible films; antifungal effect in cherry tomatoes.

Thymol nanoemulsions were produced by spontaneous emulsification, ultrasound, and a combination of both methods. The best result in terms of size and polydispersion was spontaneous emulsification where thymol was efficiently encapsulated, the nanoemulsions inhibited Botrytis cinerea at 110 ppm of thymol. A 10% dilution of this nanoemulsion in water was used to prepare quinoa-chitosan films. The film microstructure was porous and heterogeneous. The tensile strength of the film was significantly lower but its mean elongation at break was similar to that of the control film. The water vapour permeability was similar to that of the control film. The effect of nanoemulsion-thymol-quinoa protein/chitosan coating on mould growth in inoculated cherry tomatoes was evaluated. Compared with control samples (tomatoes without coating and those coated with quinoa protein/chitosan), tomatoes with this coating and inoculated with B. cinerea showed a significant decrease in fungal growth after 7 days at 5 °C.

Shelf-life of fresh blueberries coated with quinoa protein/chitosan/sunflower oil edible film.

BACKGROUND: The aim of this study was to evaluate quinoa protein (Q), chitosan (CH) and sunflower oil (SO) as edible film material as well as the influence of this coating in extending the shelf-life of fresh blueberries stored at 4 °C and 75% relative humidity. These conditions were used to simulate the storage conditions in supermarkets and represent adverse conditions for testing the effects of the coating. The mechanical, barrier, and structural properties of the film were measured. The effectiveness of the coating in fresh blueberries (CB) was evaluated by changes in weight loss, firmness, color, molds and yeast count, pH, titratable acidity, and soluble solids content. RESULTS: The tensile strength and elongation at break of the edible film were 0.45 ± 0.29 MPa and 117.2% ± 7%, respectively. The water vapor permeability was 3.3 × 10(-12) ± 4.0 × 10(-13) g s(-1) m(-1) Pa(-1). In all of the color parameters CB presented significant differences. CB had slight delayed fruit ripening as evidenced by higher titratable acidity (0.3-0.5 g citric acid 100 g(-1)) and lower pH (3.4-3.6) than control during storage; however, it showed reduced firmness (up to 38%). CONCLUSION: The use of Q/CH/SO as a coating in fresh blueberries was able to control the growth of molds and yeasts during 32 days of storage, whereas the control showed an increasing of molds and yeast, between 1.8 and 3.1 log cycles (between 20 and 35 days).

Effect of edible quinoa protein-chitosan based films on refrigerated strawberry (Fragaria × ananassa) quality

Background Strawberries are non-climacteric fruits with a low respiration rate, but are subject to serious fungal deterioration during postharvest handling. The edible coatings based on chitosan (CH), quinoa protein-chitosan (Q/CH) and quinoa protein-chitosan-sunflower oil (Q/CH/SO) may provide a solution to this problem. Thus, in this work CH, Q/CH and Q/CH/SO were elaborated and applied to fresh strawberries, and its effect on the strawberries shelf life during storage for 15 d was evaluated by mold and yeast count, fungal decay, carbon dioxide rate, physicochemical properties, and sensory evaluation. Results On all analysis days, the strawberries coated with the film-forming CH, Q/CH and Q/CH/SO solutions presented a significant lower amount of mold and yeast growth than the uncoated strawberries. Coated strawberries with Q/CH/SO decreased the CO2 emission rate by 60% compared to the uncoated strawberries. The color of the strawberries was not influenced by the films. There was no significant difference between the different coating groups and the uncoated group in the physicochemical parameters. Sensory analysis showed that the coating application retained the total sensorial quality. Conclusions Fresh strawberries coated with CH, Q/CH/SO and Q/CH edible films had longer shelf lives than uncoated fruits.

Spray Freeze-Drying as an Alternative to the Ionic Gelation Method to Produce Chitosan and Alginate Nano-Particles Targeted to the Colon.

Chitosan and alginate nano-composite (NP) carriers intended for colonic delivery containing prednisolone and inulin were obtained by two processes. Spray freeze-drying using chitosan (SFDC) or alginate (SFDA) was proposed as an alternative to the traditional chitosan-tripolyphosphate platform (CTPP). NPs were fully characterised and assessed for their yield of particles; level of prednisolone and inulin release in phosphate and Krebs buffers; and sensitivity to degradation by lysozyme, bacteria and faecal slurry. NPs based on chitosan showed similar properties (size, structure, viscoelastic behaviour), but those based on SFDC showed a higher mean release of both active ingredients, with similar efficiency of encapsulation and loading capacity for prednisolone but lower for inulin. SFDC was less degraded in the presence of lysozyme and E. coli and was degraded by B. thetaiotaomicron but not by faecal slurry. The results obtained with SFDA were promising because this NP showed good encapsulation parameters for both active ingredients and biological degradability by E. coli and faecal slurry. However, it will be necessary to use alginate derivatives to reduce its solubility and improve its mechanical behaviour.

Release of prednisolone and inulin from a new calcium-alginate chitosan-coated matrix system for colonic delivery.

Putative colonic release formulations of calcium (Ca)-alginate coated with chitosan containing two different actives, prednisolone and inulin, were prepared in three different sizes, beads (D50 = 2104 µm) and microparticles (D50 = 354 and 136 µm). The formulations were tested in standard phosphate buffer and biorelevant Krebs bicarbonate buffer at pH 7.4, and were further evaluated in the presence of the bacterium E. coli. Product yield and encapsulation were higher with prednisolone than with inulin. In Krebs bicarbonate buffer, a clear relationship between particle size and prednisolone release was observed. In contrast, release of inulin was independent of the particle size. In phosphate buffer, the particles eroded quickly, whereas in Krebs buffer, the particles swelled slowly. The difference in behavior can be attributed to the formation of calcium phosphate in the phosphate buffer medium, which in turn weakens the Ca-alginate matrix core. In the presence of E. coli, the formulations were fermented and the release of prednisolone was accelerated. In conclusion, the buffer media affects formulation behavior and drug release, with the bicarbonate media providing a better simulation of in vivo behavior. Moreover, the susceptibility of the formulations to bacterial action indicates their suitability as carriers for colonic drug delivery.

Caracterización bioquímica, fisicoquímica y funcional de turbot (Scophthalmus maximus) y estudio de sus modificaciones durante el almacenamiento a 4ºC / Biochemical, physicochemical and functional characterization of turbot (Scophthalmus maximus). Study of the changes occurring during the 4ºC storage

El turbot es un pez plano (Scophthalmus maximus), es uno de los peces que se adapta muy bien al cultivo intensivo en granja. Es necesario conocer sus propiedades fisicoquímicas-bioquímicas-tecnológicas y cómo éstas cambian durante su almacenamiento una vez que han sido cosechados. El objetivo de este estudio fue evaluar la composición centesimal, propiedades bioquímicas, fisicoquímicas y funcionales, y cómo se ven influidas por el almacenamiento a 4ºC durante 16 días. Se determinó su composición proximal, electroforesis en geles de poliacrilamida desnaturantes (PAGE-SDS), estabilidad térmica proteica a través de calorimetría diferencial de barrido (DSC). Se evaluó pH, nitrógeno básico volátil total (NBV-T), pérdida por goteo, textura, capacidad de retención de agua (CRA), emulsificación (CE) y gelificación (CG). El análisis proximal fue: humedad 76,3%; proteínas 19,6%; lípidos 2,71%; cenizas 1,3%. Se encontraron dos transiciones térmicas (DSC) a 47,5°C (miosina) y 76,9ºC (actina). PAGE-SDS mostraron perfiles correspondientes a proteínas miofibrilares y sarcoplasmáticas y durante el almacenamiento no se vieron alterados El pH cambió desde 5,9 a 6,6; las NBV-T variaron desde 20,0 a 39,5 mg NBVT/100 g músculo al día 16. CRA presentó valores de 10,5% y llegando al final a 58,1%, sin embargo no presentó CG. La CE y CRA aumentaron por el almacenamiento debido a cambios conformacionales de las proteínas. El esfuerzo de compresión fluctuó entre 111,2 a 106,0 N; el esfuerzo de cizalla fue disminuyendo en el tiempo de almacenamiento desde 148,6 a 95,2 N. La pérdida por goteo varió entre 1,7% a 2,5%. El estudio de almacenamiento refrigerado por 16 días, permitió concluir que el parámetro de frescura de NBV-T, sobrepasa el límite permitido de comercialización a los 14 días de almacenamiento, determinando de esa forma su vida útil.

The turbot (Scophthalmus maximus) is a kind of flatfish that is well adapted to intensive farm culture. After the harvest it is necessary to know the physicochemical, biochemical and technological properties and if during the refrigerated storage, changes of these properties are developed. The main objective of the study was the assessment of the proximal composition, the biochemical, physicochemical and functional properties, and how they are influenced during the 16 days storage at 4º C. Parameters such as centesimal composition, PAGE-SDS, and protein thermal stability through a DSC were carried out. pH, total volatile base-nitrogen (TVBN) dripping, texture, holding water capacity (WHC), emulsification (EC) and gelification (GC) were also determined. Results for the proximal composition were: humidity 76,3%; fat content 2,71%; proteins 19,6%; and ashes 1,3%. Two different thermal transitions at 47,5°C (myosin) and 76,9°C (actin) were observed. The PAGE-SDS showed profiles corresponding to myofibrilars and sarcoplasmatic proteins, which presented no changes during the storage. pH experimented an increase from 5,9 to 6,6; TVB-N showed a variation from 20,0 to 39,5 mg TVB-N/100 g of muscle at the day 16. The WHC started with a 10,5% and ended in 58,1%; no GC was observed. The increase of the EC and WHC during the storage was due to conformational changes of proteins. The compression force presented a fluctuation between 111,2 and 106,0 N and the shear strain decreased during the storage from 148,6 to 95,2 N. The dripping showed a variation between 1,7% and 2,5%. According to the results of the storage during 16 days at 4ºC, the NBV-T content determined a shelf life of 14 days.

[Biochemical, physicochemical and functional characterization of turbot (Scophthalmus maximus). Study of the changes occurring during the 4 degrees C storage]. / Caracterización bioquímica, fisicoquímica y funcional de turbot (Scophthalmus maximus) y estudio de sus modificaciones durante el almacenamiento a 4 degrees C.

The turbot (Scophthalmus maximus) is a kind of flatfish that is well adapted to intensive farm culture. After the harvest it is necessary to know the physicochemical, biochemical and technological properties and if during the refrigerated storage, changes of these properties are developed. The main objective of the study was the assessment of the proximal composition, the biochemical, physicochemical and functional properties, and how they are influenced during the 16 days storage at 4 degrees C. Parameters such as centesimal composition, PAGE-SDS, and protein thermal stability through a DSC were carried out. pH, total volatile base-nitrogen (TVB-N) dripping, texture, holding water capacity (WHC), emulsification (EC) and gelification (GC) were also determined. Results for the proximal composition were: humidity 76.3%; fat content 2.71%; proteins 19.6%; and ashes 1.3%. Two different thermal transitions at 47.5 degrees C (myosin) and 76.9 degrees C (actin) were observed. The PAGE-SDS showed profiles corresponding to myofibrilars and sarcoplasmatic proteins, which presented no changes during the storage. pH experimented an increase from 5.9 to 6.6; TVB-N showed a variation from 20.0 to 39.5 mg TVB-N/100 g of muscle at the day 16. The WHC started with a 10.5% and ended in 58.1%; no GC was observed. The increase of the EC and WHC during the storage was due to conformational changes of proteins. The compression force presented a fluctuation between 111.2 and 106.0 N and the shear strain decreased during the storage from 148.6 to 95.2 N. The dripping showed a variation between 1.7% and 2.5%. According to the results of the storage during 16 days at 4 degrees C, the NBV-T content determined a shelf life of 14 days.

The effect of chitosan as internal or external coating on the 5-ASA release from calcium alginate microparticles.

The effect of chitosan as internal or external coating on the mesalamine (5-ASA) release from calcium alginate microparticles (CaAl) was studied, and a delayed release of 5-ASA system intended for colonic drug delivery was developed. The external chitosan coating was developed by immersion of wetted CaAl in chitosan solution and the internal coating by mixing 5-ASA with chitosan solution and drying before the preparation of CaAl. Both systems were coated with Acryl-EZE® using combined fluid bed coating and immersion procedure. The results showed that in phosphate medium (pH 7.5), chitosan as 5-ASA coating promotes a quick erosion process accelerating drug release, but chitosan as external coating (CaAlCS) does not increase the T (50) value compared with the microparticles without chitosan (CaAl). Chitosan as internal or external coating was not effective to avoid the quick 5-ASA release in acidic medium (pH 1.2). The presence of ß-glucosidase enzymes increases significantly the 5-ASA release for CaAl, while no effect was observed with chitosan as internal or external coating. Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray data revealed that 5-ASA did not form a solid solution but was dispersed in the microparticles. The Acryl-EZE® coating of microparticles was effective because all the formulations showed a low release, less than 15%, of 5-ASA in acid medium at pH 1.2. Significant differences in the percentage of 5-ASA released between formulations were observed in phosphate buffer at pH 6.0. In phosphate buffer at pH 7.2, all the formulations released 100% of 5-ASA.

Study of some physicochemical and functional properties of quinoa (chenopodium quinoa willd) protein isolates.

The amino acid composition and the physicochemical and functional properties of quinoa protein isolates were evaluated. Protein isolates were prepared from quinoa seed by alkaline solubilization (at pH 9, called Q9, and at pH 11, called Q11) followed by isoelectric precipitation and spray drying. Q9 and Q11 had high levels of essential amino acids, with high levels of lysine. Both isolates showed similar patterns in native/SDS-PAGE and SEM. The pH effect on fluorescence measurements showed decreasing fluorescence intensity and a shift in the maximum of emission of both isolates. Q9 showed an endotherm with a denaturation temperature of 98.1 degrees C and a denaturation enthalpy of 12.7 J/g, while Q11 showed no endotherm. The protein solubility of Q11 was lower than that of Q9 at pH above 5.0 but similar at the pH range 3.0-4.0. The water holding capacity (WHC) was similar in both isolates and was not affected by pH. The water imbibing capacity (WIC) was double for Q11 (3.5 mL of water/g isolate). Analysis of DSC, fluorescence, and solubility data suggests that there is apparently denaturation due to pH. Some differences were found that could be attributed to the extreme pH treatments in protein isolates and the nature of quinoa proteins. Q9 and Q11 can be used as a valuable source of nutrition for infants and children. Q9 may be used as an ingredient in nutritive beverages, and Q11 may be used as an ingredient in sauces, sausages, and soups.

Estudio de las modificaciones en proteínas de reineta (Bramas australis): sometidas a congelación y almacenamiento a 18°C y 30°C / Stydy of the reineta protein modifications (Brama australis): put under freezing and storage to 18°C and 30°C

El presente trabajo tuvo como objetivo estudiar las propiedades funcionales y térmicas en carne de reineta (Brama australis) congelada, mediante los análisis de capacidad de retención de agua (CRA), capacidad formadora de gel (CFG), textura, capacidad emulsionanate (CE) y calorometría diferencial de barrido (DSC). Para este estudio se utilizaron filetes de reinetas obtenidos y extraídos bajo las mismas condiciones, los cuales fueron trozados, envasados, congelados y almacenados a temperaturas de 18°C y 30°C durante siete meses. Los resultados para todos los tratamientos térmicos empleados no mostraron diferencias estadísticamente significativas entre individuos. Para los pescados congelados a 18°C y 30°C, los valores de proteínas totales fructuaron entre 23,5 ± 0,0 y 25,4 ± 1,0 por ciento respectivamente. Para el caso de CRA los valores se encontraron en un rango de 0,45 ± 0,1 y 1,59 ± 0,0 g agua/ g proteínas. En cuanto a la CFG sólo hubo formación de gel para la reineta fresca, existiendo producción de agregados de protéicos para las muestras almacenadas. Por otra parte los valores de CE fluctuaron entre 960 a 1400 g de aceite/g proteína, con una tendencia al aumento a medida que el tiempo de almacenamiento fue mayor. Para el caso del DSC los valores de temperatura y desnaturalización (T) y entalpía de desnaturalización (?H) de miosina fluctuaron entre 39,2 ± 0,5 y 44,8 ± 0,8°C y entre 1,12 ± 0,3 y 0,52 ± 0,2 J/g. Para la actina los valores fluctuaron entre 71,0 0,6 y 75,3 ± 0,5°C y entre 0,5 ± 0,1 y 0,7 ± 0,1 J/g, la cooperatividad disminuyó a medida que pasó el tiempo, lo cual está demostrando un cierto grado de desplazamiento de las proteínas. Los valores encontrados para propiedades térmicas presentan una directa relación con respecto a los valores de propiedades funcionales estudiadas, presentando ambos una disminución en el tiempo

[Study of the reineta protein modifications (Brama australis), put under freezing and storage to -18 degrees C and -30 degrees C]. / Estudio de las modificaciones en proteínas de reineta (Brama australis), sometidas a congelación y almacenamiento a -18-C y-30-C.

The objective of the present work was to study functional and thermal properties of reineta (Brama australis) frozen meat, analysed by water retention capacity (WRC), gel forming capacity (GFC), texture, emulsifying capacity and differential scanning calorimetry (DSC). For this study, reineta fillets were obtained and extracted by the same conditions, and cutted, packaged, frozen and stored at -18 degrees C and -30 degrees C for 7 months. The results obtained, showed that there were no signifficant differences in the responses to thermal treatment for all the specimens. For samples frozen at -18 degrees C and -30 degrees C, the protein contents were 23.5 + 0.0 and 25.4 + 1.0%, respectively. The WRC values were 0.45 + 0.1 and 1.59 +/- 0.0 g water/g protein, respectively. The gel forming capacity was only present in the fresh samples, whereas the frozen stored ones only form protein aggregates. The emulsifying capacity was between 960 and 1400 g oil / g protein, and the storage time increased this value. The miosin denaturation temperature (Td) and denaturation enthalpy (?H), obtained by DSC, fluctuated between 39.2 +/- 0.5 to 44.8 +/- 0.8 degrees C and 1.12 +/- 0.3 to 0.52 +/- 0.2 J/g, respectively. The actina values were between 71.0 +/- 0.6 to 75.3 +/- 0.5 degrees C and between 0.5 +/- 0.1 to 0.7 +/- 0.1 J/g. Cooperativity decreased as the storage time increased. This is showing a certain degree of protein displacement. The values found by thermal analyses showed a direct relationship with the functional properties, both decreasing with storage time.

[Effect of thermal treatments on the chemical characteristics of mora crab meat (Homalaspis plana)]. / Efecto de tratamientos térmicos sobre las características químicas de carne de jaiba mora (Homalaspis plana).

Marine species muscles present non-proteins nitrogenated compounds, used as quality index. They are total volatile basis (NBVT), trimethylamine oxide (TMAO) and trimethylamine (TMA). pH is considered too as a quality index. The aim of this work was to evaluate these parameters in a fresh and canned marine product from the V region, corresponding to mora crab (Homalaspis plana). Fresh pincer meat from mora crab was extracted and kept in ice until theits analysis and thermal process of the canned product. A 3(2) statistical design was applied, considering two variables with 3 levels: 15, 30 y 45 minutes time levels: 80 degrees, 100 degrees y 121 degrees C temperature levels. Nine conditions of time-temperature were obtained. The thermal treatment caused an increase in pH and BVT. The TMA was increased since reduction of TMAO.

Influence of the extracting solvent upon the structural properties of Amaranth (Amaranthus hypochondriacus) glutelin.

Two amaranth glutelin preparations, Gt-bo extracted with borate buffer at pH 10 and Gt-na extracted with 0.1 N NaOH, were characterized and compared with the amaranth polymerized 11S globulin (Gp, globulin-P). Gt-bo and Gt-na presented very similar polypeptidic composition and a similar reactivity against an anti-Gp polyclonal antibody, although lower than that of Gp. It is demonstrated that Gt-na is composed of denatured and dissociated molecules, whereas Gt-bo consists of folded molecules. The size, polypeptidic composition, thermal stability, and denaturation enthalpy of Gt-bo molecules were similar to those of Gp subjected to a borate treatment at pH 10. The Gp immunoreactivity decreased to the level of Gt reactivity when subjected to alkaline treatment; this could be due to conformational changes. Results suggest that, like Gp, amaranth Gt molecules may be hexameric oligomers of approximately 300 kDa. They would be partially unfolded during the alkaline extraction.

Efecto de tratamientos térmicos sobre el contenido de lisina disponible en carne de jaiba mora (Homalaspis plana) / Effect of thermal treatment on the available lysine content of mora crab (Homalaspis plana) meat

The effect of different high temperatures treatments on the available lysine content of mora crab meat, was studied. Fresh pincer meat from mora crab (from the V region) was extracted and kept in ice until the thermal process of the canned product. A 3(2) statistical design was applied, considering the following variables temperature (80 degrees C, 100 degrees C and 121 degrees C) and time (15, 30 and 45 minutes). Nine conditions temperature-time were obtained. Nutritional properties from available lysine were studied. A decrease from 8.33 (in raw meat) to 6.01 g/g protein in the most drastic thermal conditions, was observed. It ca be concluded that the content of available lysine in mora crab meat is more affected by time than by the temperature of the thermal treatments. Therefore the nutritive quality can be maintained applying high temperature and short time treatments.

Caracterización funcional y bioquímica de la carne del manto de jibia (dosidicus gigas) / Biochemistry and functional characterization of squid mantle meat (dosidicus gigas)

En el presente trabajo se realizó la caracterización funcional y bioquímica de la carne del manto de jibia (dosidicus gigas) almacenada a -25ºC por 6 meses. Se estudiaron la capacidad emulsionante, capacidad de retención de agua y la capacidad de gelificación. Además se buscaron las condiciones óptimas para la separación y diferenciación de las proteínas miofibrilares de las sarcoplasmáticas. Dentro de las propiedades funcionales se encontró que la carne descongelada del manto de jibia es capaz de emulsionar 2.817,4 g aceite/g proteína, de retener 3,64 g agua/g proteína. La capacidad de formar geles fue nula, lo cual se atribuyó al tiempo de almacenamiento. Respecto a la obtención de proteínas miofibrilares de carne del manto de jibia, se concluyó que con dos lavados a baja fuerza iónica (I=0,05), las proteínas sarcoplasmáticas son eliminadas de la matriz proteica. Mediante la realización de PAGESDS, de los extractos de carne de manto de jibia obtenidos a dos fuerzas iónicas diferentes (I=0,5 y I=0,05), se logró diferenciar las proteínas miofibrilares de las sarcoplasmáticas. Del estudio realizado se deduce que las proteínas del manto jibia poseen una buena capacidad de emulsionar y retener agua, por lo que se puede considerar una muy buena materia prima para el desarrollo de productos para untar. En el caso de productos gelificados, es necesario realizar estudios complementarios en la carne fresca para poder inferir en relación a esta propiedad funcional

Determinación de la composición químico-proximal y la formulación de un producto tipo gel jibia (dosidicus gigas) / Determination of proximal chemical composition of squid (Dosidicus gigas) and development of gel product

Se realizó un estudio de la carne del manto de jibia (dosidicus gigas), cefalópodo que habita casi la totalidad de la costa chilena. Se determinó la caracterización químico-proximal determinándose que la jibia presenta buenas características nutricionales, por el alto contenido de proteínas y bajo contenido de grasa. Los resultados de la caracterización química fueron los siguientes; calorías/100g de carne: 70. (por cálculo); humedad: 82.23 ñ 0,98 por ciento; proteínas: 15,32 ñ 0,93 por ciento; cenizas: 1,3 ñ 0,12 por ciento; grasa: 0,87 ñ 0,18 por ciento; ENN: 0,27 por ciento ( por diferencia). Por otra parte, se elaboró un producto tipo gel con carne de jibia, en estudios previos se definió el contenido de NaCI y tripolifosfato de sodio; además de otros aditivos que confieren características de gel. Finalmente se seleccionaron formulaciones que contenían carragenina, alginato de sodio y albúmina de huevo, cada una en tres concentraciones diferentes. A estas formulaciones se les midió la fuerza de gel. Los valores más altos de la fuerza de gel, obtuvieron con la adición de albúmina de huevo, seguida de carragenina y de alginato que dio baja fuerza de gel, los resultados indicaron que la carne de jibia, no presentó buenas propiedades de gelificación