Evolución de la proteólisis durante la maduración de quesos Danbo elaborados con distintos cultivos iniciadores

La determinación de nitrógeno soluble a pH 4,6 (NNC), nitrógeno soluble en ácido tricloroacético (12 %) (NTCA) y nitrógeno soluble en ácido fosfotúngstico (5 %) (NPTA) se utiliza como índice de maduración de quesos, ya que proporciona información adecuada de la extensión global de la proteólisis. La formación de péptidos y aminoácidos durante la maduración del queso contribuye directamente al desarrollo del sabor y textura del queso, de allí la importancia de conocer si el uso de distintos cultivos iniciadores genera diferencias en el desarrollo de la proteólisis. En este trabajo se estudiaron los cambios proteolíticos durante la maduración de quesos Danbo elaborados con cultivos iniciadores que difieren en la proporción de sus microorganismos componentes: Lote A con: 60 % Streptococcus thermophilus subsp. thermophilus – 40 % (Lactococcus lactis subsp. lactis + Lactococcus lactis subsp. cremoris) y Lote B con: 50 % Streptococcus thermophilus subsp. thermophilus – 50 % (Lactococcus lactis subsp. lactis y Lactococcus lactis subsp. cremoris). Se analizaron quesos con 0, 15, 30 y 45 días de maduración y se determinó contenido de humedad, pH, contenido de nitrógeno en queso y contenido de nitrógeno de las distintas fracciones nitrogenadas. El lote elaborado con un mayor porcentaje de cultivo mesófilo (Lactococcus lactis subsp. lactis y Lactococcus lactis subsp. cremoris), lote B, fue el que presentó mayor proteólisis primaria y mayor formación de oligopéptidos y aminoácidos libres

Fast Electrochemical Method for Organic Dye Decolorization Using Recycled Li-Ion Batteries

In this paper, the application of recycled Li-ion battery spent cathodes (LIB-SC) combined with a NaHCO3/H2O2 system is presented for the first time in the literature as an alternative for the degradation of potentially toxic organic molecules. The model pollutant choice was methylene blue molecule. The spent cathode composition corresponds to LiCoO2, which was proved by the XRD and EDX. Regarding the decolorization of methylene blue solution, the addition of NaHCO3, in comparison with only H2O2, reduces the complete decolorization time by 96%. This reduction occurs because the radical CO 3 . is more stable than OH. In this way, the application of the system proposed in this article is aimed at solving two major global problems: the disposal of cell phone batteries and the pollution of liquid effluents

ELECTROCHEMICAL CORROSION STUDY VIA LINEAR POLARIZATION IN PEAS CAN

The aim of this work is to study the corrosion of tinplate can for peas. Firstly, the characterization of canning solution was made. The values of pH, conductivity, Brix, viscosity, density and content of Fe were, respectively, 5.88; 32.6 mS/cm; 6.6%; 3,42cP; 1.026 g/ml; 12.05 mg/kg. The corrosion rate in the cans was determined by linear polarization technique. The electrodes with and without varnish were analyzed in the first and fifth day of the experiment for the 3 parts of the can. The corrosion rate increased significantly when the coating was removed and the body showed a higher corrosion rate, reaching 1.7 mm/year in the absence of varnish. The microstructure of the samples was evaluated by scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The increase of iron on the surface, evidenced by energy dispersive spectroscopy (EDS) may have contributed to the corrosion in the samples without varnish

PRACTICAL LESSONS: IMPORTANT TOOL IN THE NATURAL SCIENCE TEACHING

The practical lessons are a powerful tool for the learning process improvement in science subjects, especially in chemistry field, as they provide a better association of practice and theory, problem solving and daily inquiries. This project aimed to enhance and encourage learning in science as well as collaborating with the formation of young students from public schools. Took part in this project around 70 youngsters from the first year of high school. Two questionnaires were applied to the students, one before starting the research and another at the end, through which we could observe an excellent development of the students regarding the scientific concepts and school performance. Throughout the year practical activities were developed, with content related to daily life, always making usage of alternative materials and a booklet, which was developed to assist this project. The lessons were developed in their classroom. It can be assured that the practical lessons were crucial to the science teaching, because they enabled a better learning theory. The results were very promising towards the development and interest of students and teachers

ANALYSIS OF PROJECT ABOUT CERRADO FRUITS DEVELOPED WITH STUDENTS FROM TWO PUBLIC SCHOOLS

The Brazilian Cerrado has enormous diversity featuring a large number of fruit native plants that have a high nutritional value and distinctive flavor. This work belongs to an extension program of Cerrado fruits, where two species stand out in this region: Cagaita tree (Eugenia dysenterica DC) and Pequi tree (Caryocar brasiliense). The same was done in a neighborhood located near the Federal University of Sao Joao del Rei, Campus of Sete Lagoas - MG and developed in two municipal schools, with the participation of students of 4th and 5th years and other servers. The goal of this project was to disseminate knowledge to the participants of the reality that surrounds them, and on these two fruits of the Cerrado, providing support materials for environmental preservation awareness. The work took four steps, one of which was to answer a questionnaire by students. The main results showed that students, teachers and cooks did not know Pequi and Cagaita, native fruit species of one of the richest biomes and threatened the world. It was possible to realize the interest of those involved in the project, in order to educate about the importance of ensuring the collection and use of these fruits for the next generations