Secondary school mathematics teachers’ professional learning in a lesson study

Background: Lesson study is an innovative professional development process, originated from Japan, that is important to know if it may be applicable in other cultural contexts. Objective: This paper analyses professional learning of mathematic teachers involved in lesson study. Design: Qualitative and interpretative research, using participant observation. Setting and participants: The participants are seventeen mathematics teachers of secondary school at the teaching public network of Rio Grande do Sul State. Data collection and analysis: Research’s empirical material consist of field notes produced in the context of lesson study sessions, teachers’ textual productions systematized in their logbooks, audio recordings of the research lesson and debriefing session. Results: The results highlight that teachers’ participation in lesson study provided them professional learning related to deepening of the curricular content to teach at classroom, as well about teaching resources to teach mathematics topics and also about the collaborative work in the school context, the reflection on professional practices and about the teacher’s education approaches prevalent in the educative settings. Conclusions: The study suggests that lesson study is a powerful professional development process both regarding mathematics teaching and professional culture

Gelatin based films capable of modifying its color against environmental pH changes

The aim of this work was to develop biodegradable protein-based films capable of sense pH changes. These protein films were prepared by casting from aqueous solutions of bovine gelatin, glycerol and three acid-base indicators: methyl orange (MO), neutral red (NR) and bromocresol green (BCG), at pH 2, 6 and 11. All resulting protein films were homogeneous, thin and had different colors depending on pH and the indicator used. The response of these materials was evaluated simulating their contact with liquid and semisolid media, and with a container headspace at acid and alkaline pH. In all tests, developed protein films could modify their color after being in contact with media of different pH. The physicochemical properties of films were also affected differently by the presence of each acid-base indicator. While the addition of BCG did not significantly modify the properties of control gelatin films, except its color; the incorporation of MO and NR into film-forming solutions significantly improved mechanical properties and decreased the water solubility and moisture content of the resulting protein films without affecting their water vapor permeability.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Caracterización de almohadillas liberadoras de SO2 en base a proteínas de soja para la prevención de pardeamiento en manzanas frescas cortadas

The use of polymeric matrices releasing active principles is a promising strategy to circumvent dipping treatments and reduce additive usage. Herein, we developed soy protein-based films containing 0, 10, 25 or 50% sodium sulfite on protein isolate basis (SPI), and determined the influence of the antioxidant on the color, thickness, opacity, solubility, moisture, water permeability and mechanical properties of the resulting materials. Raising sulfite concentration reduced the tensile strength, without affecting the Young´s modulus of the films. The formulation containing 50% sodium sulfite on SPI basis was selected based on the lighter color, lowest moisture and higher permeability of the resulting films to evaluate the efficacy of the materials to prevent apple browning. The incorporation of SO2-releasers in packages containing fresh-cut apples delayed fruit yellowing (increase of b*values) by 40%. This shows that sodium sulfite soy protein based films may be useful to extend the postharvest life of fresh-cut apple.Centro de Investigación y Desarrollo en Criotecnología de AlimentosLaboratorio de Investigación en Productos Agroindustriale

Fish oil-in-water emulsions stabilized by soy proteins and cellulose nanocrystals

This work aimed to develop fish O/W emulsions using soy protein isolate (SPI) and cellulose nanocrystals (CNC) either as separate stabilising agents or in combination. The fish O/W emulsions were prepared using aqueous dispersions containing SPI and/or different concentrations of CNC at neutral pH. The effects of each component and their concentration on the microstructure, droplet size, zeta potential, rheological behaviour, and stability of the resulting emulsions during its quiescent storage at room temperature were analysed. Emulsions prepared with both SPI and CNC showed droplets with larger sizes and surface charge than those stabilized only by SPI and were more stable than those stabilized by each component separately. The concentration of CNC determined the physicochemical and rheological properties of SPI + CNC emulsions, as well as the intervening destabilization mechanisms. Emulsion stabilized by SPI + 0.1% CNC that had a high degree of initial flocculation, turned out to be the most stable during 15 days of quiescent storage at room temperature.Fil: Di Giorgio, Luciana. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Salgado, Pablo Rodrigo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Mauri, Adriana Noemi. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin

Caracterización de almohadillas liberadoras de SO2 en base a proteínas de soja para la prevención de pardeamiento en manzanas frescas cortadas

The use of polymeric matrices releasing active principles is a promising strategy to circumvent dipping treatments and reduce additive usage. Herein, we developed soy protein-based films containing 0, 10, 25 or 50% sodium sulfite on protein isolate basis (SPI), and determined the influence of the antioxidant on the color, thickness, opacity, solubility, moisture, water permeability and mechanical properties of the resulting materials. Raising sulfite concentration reduced the tensile strength, without affecting the Young’s modulus of the films. The formulation containing 50% sodium sulfite on SPI basis was selected based on the lighter color, lowest moisture and higher permeability of the resulting films to evaluate the efficacy of the materials to prevent apple browning. The incorporation of SO2-releasers in packages containing fresh-cut apples delayed fruit yellowing (increase of b* values) by 40%. This shows that sodium sulfite soy protein-based films may be useful to extend the postharvest life of fresh-cut apple.Fil: Ortiz, Cristian Matias. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Laboratorio de Investigación en Productos Agroindustriales; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Mauri, Adriana Noemi. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Vicente, Ariel Roberto. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Laboratorio de Investigación en Productos Agroindustriales; Argentin

Smart edible films based on gelatin and curcumin

This work studied the preparation of edible smart films based on gelatin and curcumin. Films were prepared by casting using water and an ethanol-water mixture as solvents. The addition of curcumin, besides affecting the physicochemical properties of gelatin films, colored them depending on the pH of the film-forming dispersion (yellow at pH=6 and red at pH=11). It also provided films with important antioxidant properties, but no antimicrobial activity. The response of these materials against pH changes was evaluated simulating their contact with liquid and semisolid foods, and with a container headspace at acid and alkaline pH. In all tests, gelatin films with curcumin added could modify their color after being in contact with media of different pH. The use of an ethanol-water mixture as solvent was a good alternative to intensify film color and the visualization of their response capacity against pH changes, as well as to increase the antioxidant properties and hydrophobicity of films. These edible films could be used as smart food packaging, since they could inform consumers if the product was suitable for consumption through their capacity to sense pH changes.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Caracterización de almohadillas liberadoras de SO2 en base a proteínas de soja para la prevención de pardeamiento en manzanas frescas cortadas

The use of polymeric matrices releasing active principles is a promising strategy to circumvent dipping treatments and reduce additive usage. Herein, we developed soy protein-based films containing 0, 10, 25 or 50% sodium sulfite on protein isolate basis (SPI), and determined the influence of the antioxidant on the color, thickness, opacity, solubility, moisture, water permeability and mechanical properties of the resulting materials. Raising sulfite concentration reduced the tensile strength, without affecting the Young´s modulus of the films. The formulation containing 50% sodium sulfite on SPI basis was selected based on the lighter color, lowest moisture and higher permeability of the resulting films to evaluate the efficacy of the materials to prevent apple browning. The incorporation of SO2-releasers in packages containing fresh-cut apples delayed fruit yellowing (increase of b*values) by 40%. This shows that sodium sulfite soy protein based films may be useful to extend the postharvest life of fresh-cut apple.Centro de Investigación y Desarrollo en Criotecnología de AlimentosLaboratorio de Investigación en Productos Agroindustriale

Gelatin based films capable of modifying its color against environmental pH changes

The aim of this work was to develop biodegradable protein-based films capable of sense pH changes. These protein films were prepared by casting from aqueous solutions of bovine gelatin, glycerol and three acid-base indicators: methyl orange (MO), neutral red (NR) and bromocresol green (BCG), at pH 2, 6 and 11. All resulting protein films were homogeneous, thin and had different colors depending on pH and the indicator used. The response of these materials was evaluated simulating their contact with liquid and semisolid media, and with a container headspace at acid and alkaline pH. In all tests, developed protein films could modify their color after being in contact with media of different pH. The physicochemical properties of films were also affected differently by the presence of each acid-base indicator. While the addition of BCG did not significantly modify the properties of control gelatin films, except its color; the incorporation of MO and NR into film-forming solutions significantly improved mechanical properties and decreased the water solubility and moisture content of the resulting protein films without affecting their water vapor permeability.Centro de Investigación y Desarrollo en Criotecnología de Alimento

Secondary School Mathematics Teachers’ Professional Learning in a Lesson Study

Background: Lesson study is an innovative professional development process, originated from Japan, that is important to know if it may be applicable in other cultural contexts. Objective: This paper analyses professional learning of mathematic teachers involved in lesson study. Design: Qualitative and interpretative research, using participant observation. Setting and participants: The participants are seventeen mathematics teachers of secondary school at the teaching public network of Rio Grande do Sul State. Data collection and analysis: Research’s empirical material consist of field notes produced in the context of lesson study sessions, teachers’ textual productions systematized in their logbooks, audio recordings of the research lesson and debriefing session. Results: The results highlight that teachers’ participation in lesson study provided them professional learning related to deepening of the curricular content to teach at classroom, as well about teaching resources to teach mathematics topics and also about the collaborative work in the school context, the reflection on professional practices and about the teacher’s education approaches prevalent in the educative settings. Conclusions: The study suggests that lesson study is a powerful professional development process both regarding mathematics teaching and professional culture

Recent Developments in Smart Food Packaging Focused on Biobased and Biodegradable Polymers

Food packaging has a crucial function in the modern food industry. New food packaging technologies seek to meet consumers and industrial's demands. Changes related to food production, sale practices and consumers' lifestyles, along with environmental awareness and the advance in new areas of knowledge (such as nanotechnology or biotechnology), act as driving forces to develop smart packages that can extend food shelf-life, keeping and supervising their innocuousness and quality and also taking care of the environment. This review describes the main concepts and types of active and intelligent food packaging, focusing on recent progress and new trends using biodegradable and biobased polymers. Numerous studies show the great possibilities of these materials. Future research needs to focus on some important aspects such as possibilities to scale-up, costs, regulatory aspects, and consumers' acceptance, to make these systems commercially viable.Fil: Salgado, Pablo Rodrigo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Di Giorgio, Luciana. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Musso, Yanina Soledad. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Mauri, Adriana Noemi. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin