Silvana Albertini

Efeito de revestimentos comestíveis na conservação de mamões minimamente processados

Summary The experiment evaluated the effects of carbohydrate-based coatings on the microbiological, physical, physical-chemical and sensory properties of the fresh cut (FC) Formosa papaya stored under refrigeration. After treatment with calcium chloride, peeled and sliced portions of the fruit were immersed in 3.0% rice starch (RS), 0.5% sodium alginate (SA) and 0.25% carboxymethylcellulose (CMC) solutions, and stored at 5 °C and 90% RH. The products were assessed after 1, 3, 6, 9, 12 and 15 days of storage. The use of the RS, SA and CMC-based coatings for TC papaya resulted in lower total coliform counts than presented by the control sample. The papaya coated with RS and CMC showed decreased and increased respiration rates, respectively. The coated samples showed lower soluble solid contents, with decreased pH values after storage day 9, and the use of CMC as a coating resulted in increased pulp firmness on day 15. Variations in the colour parameters (Luminosity, Hue and Chroma) did not compromise the sensory quality of the TC papaya, and the sensory attributes of the coated samples did not differ from the control samples throughout the 15 days of experimentation. Since most of the positive results were shown on days 12 and 15, and considering the costs of this technology and price of the coatings, for periods of up to 9 days the best option consists of simply sanitizing the fruits, as done with the control samples. If aiming to preserve the shelf life of the papaya slices for a longer period of time (namely, up to 15 days), the above coatings may show satisfactory results so long as the storage conditions described here are accurately reproduced.

Utilização de serragem e bagaço de cana-de-açúcar para adsorção de cádmio

Metals which come from anthropogenic activities contaminate the atmosphere, inputs and raw materials and, consequently, the trophic chain, thus affecting humankind. Due to the accumulation of these metals, as well as their harmful consequences, studies are being carried out to evaluate the levels reached by such contaminations. The objective of this work was to test the capacity of the sawdust and pulp from cane, in adsorber heavy metals from model solutions of chloride of cadmium, at the concentrations of 25 and 50 mg.L-1. The triplicates of samples taken for analysis were dried in the air in an airy atmosphere, without any processes, and the experiments were done with 10 g of residue and 500 mL of solution of chloride of cadmium in PVC reactors with a capacity of 1300 mL, where the homogeinization was made manually during the contact of 16 hours25. As the capacity of adsorption of the metal for the residue was not drained at first, the possibility of a new contact reusing the remaining solution was studied, maintaining the proportion at 1:5025. In a second stage they were tested at times of 12, 8 and 4 hours. The amount of cadmium was determined by the atomic absorption spectrofotometry (AAS) in the contact solution, after separating the residue for filtration. According to the results, we can say that these residues can be used as adsorbents of heavy metals in effluent treatment.

Effects of chemical treatments on fresh-cut papaya

Four treatments (control, 0.1% cinnamaldehyde, 0.75% calcium chloride and combination of 0.1% cinnamaldehyde and 0.75% calcium chloride) were used to evaluate chemical effects on shelf life, quality and sensory acceptability of fresh-cut papaya (Carica papaya L.). Papaya slices were packed and covered with polypropylene film, stored at 5 °C; and evaluated after 1, 3, 6, 9, 12, and 15 days for microbiological and physicochemical changes. A sensory evaluation was performed at 1, 3, 6, 9, and 12 days. There was no occurrence of Salmonella, Escherichia coli or psychotropic bacteria. The cinnamaldehyde alone and a combination of cinnamaldehyde and calcium chloride treatments yielded better control of the total coliforms. The combination treatment decreased the CO2 concentration and increased the maintenance of papaya firmness. All the treatments had acceptability. The combination treatment was the most effective treatment for flavor, taste, and preservation until day 12.

Efeito de tratamentos químicos na respiração e parâmetros físicos de melão 'Amarelo' minimamente processado

The effect of the application of chemical treatments was evaluated on the respiratory activity and the impact on the physical parameters of fresh cut melons. Selected fruits were washed and sanitized and minimally processed in cubes, divided in four lots which consisted of: control, treated with calcium chloride (1%), with ascorbic acid (1%) and coated with sodium alginate (1%). The cubes were packed in trays with cover of polyethylene terephtalate (PET) and stored at 5±1oC and 73±5% HR, during 12 days. The cubes were evaluated on their respiratory rate, ethylene production, loss of fresh mass, coloration, texture and humidity content. During the period of storage, independent of the treatment, a reduction of the respiratory rate occurred; ethylene production was not detected in fruits. Chemical treatments had no influence on loss of fresh mass, texture and humidity content; however the film of sodium alginate resulted in darker coloration of melon pulp due to the film solution color.

Determinação de isotermas de adsorção de Saccharomyces cerevisiae empregando acetato e sulfato de cádmio

To determine the isotherms of the adsorption of cadmium for Saccharomyces cerevisiae, acetate and sulphate salts were used at the concentrations of 5, 10, 20, 40, 60, 80, and 100 mg.L-1. The biomass was produced from a starter culture of Saccharomyces cerevisiae IZ 1904. After the contact of 16 hours among the microrganism study and the solution-test, the biomass was separated by a centrifugation and the cadmium residue content was determined directly in the supernatant by atomic absorption spectrophotometry. For the two salts which were used, a growing accumulation of cadmium was observed at concentrations of 5, 10, 20, and 40 mg.L-1. In the concentrations of 60; 80 and 100 mg.L-1 a decrease in the accumulation of the metal was observed, showing damage to the cellular wall, not always observed at the membrane citoplasmatics level, visualized by a scanning electron microscopy.