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Effects of the mechanical damage on the water absorption process by corn kernel

The purpose of this study was to investigate and model the water absorption process by corn kernels with different levels of mechanical damage Corn kernels of AG 1510 variety with moisture content of 14.2 (% d.b.) were used. Different mechanical damage levels were indirectly evaluated by electrical conductivity measurements. The absorption process was based on the industrial corn wet milling process, in which the product was soaked with a 0.2% sulfur dioxide (SO2) solution and 0.55% lactic acid (C3H6O3) in distilled water, under controlled temperatures of 40, 50, 60, and 70 oC and different mechanical damage levels. The Peleg model was used for the analysis and modeling of water absorption process. The conclusion is that the structural changes caused by the mechanical damage to the corn kernels influenced the initial rates of water absorption, which were higher for the most damaged kernels, and they also changed the equilibrium moisture contents of the kernels. The Peleg model was well adjusted to the experimental data presenting satisfactory values for the analyzed statistic parameters for all temperatures regardless of the damage level of the corn kernels.

Influence of packaging on the quality of Brazil nuts

The Brazil nut is an important commodity that grows in the Amazon rainforest and is notable for its high nutritional value. However, the effect that packaging has on product shelf-life is unclear. This study evaluated the microbiological and nutritional quality of unshelled Brazil nuts packed in (a) nylon and polypropylene under vacuum, and (b) in polyethylene terephthalate and polyethylene aluminized films. The nuts were stored for nine months under natural environmental conditions. The most probable number of total and thermotolerant coliforms and Escherichia coli, and counting of molds and yeast were determined in the unshelled nuts shortly after collection and every three months during storage. Moisture, lipids, ash, neutral detergent fiber, and acid detergent fiber contents were measured by the gravimetric method. Crude protein content was measured using the Kjeldahl method. Coliform levels were within legislated standards in both types of packaging. Mold and yeast growth increased with time in both types of packaging (0.1x101 to 9.5x103 colony forming units g-1), but only nuts packaged in aluminum film showed a significant increase after six months of storage. After nine months of storage, both types of packaged nuts had good nutritional quality. Aluminized packaging resulted in better conservation of the lipid fraction and lower permeability to water vapor, however, vacuum packaging was more effective in controlling fungal growth, possibly due to the lack of oxygen.

INFLUÊNCIA DA TEMPERATURA DE SECAGEM SOBRE AS PROPRIEDADES FÍSICAS DOS GRÃOS DE SOJA - DOI: 10.13083/1414-3984/reveng.v23n3p212-219

The objective of this study was to evaluate the effect of drying temperature on physical properties of soybeans. To evaluate the effect of temperature, soybean samples with an initial moisture content of 0.244 (db) were dried in an standard hot air oven at temperatures of 40, 50, 60, 70 and 80 °C until reaching the final moisture content of 0.136 (db), followed by determining the physical properties: angle of repose, bulk density, real density, one thousand grain weight, color and electrical conductivity of the solution of the soybean exudates. It was noted that the drying temperature significantly influenced the physical properties of soybeans, resulting in increased angle of repose and electrical conductivity of the exudate solutions. The bulk and real densities, one thousand grain weight and the characteristic color of soybeans decreased with increasing drying temperature. It was concluded that as the drying temperature increase there was a decrease in quality of the grains analyzed.

Chemical treatment of papaya seeds aiming at long-term storage and control of damping off 1

Damping off is a nursery disease of great economic importance in papaya and seed treatment may be an effective measure to control. The aim of this work was to evaluate the quality of papaya seeds treated with fungicides and stored under two environmental and packaging conditions. Additionally, the efficiency of fungicide treatments in the control of damping-off caused by Rhizoctonia solani was evaluated. Papaya seeds were treated with the fungicides Captan, Tolylfluanid and the mixture Tolylfluanid + Captan (all commercial wettable powder formulations). Seeds of the control group were not treated. The seeds were stored for nine months in two conditions: packed in aluminum coated paper and kept at 7 ± 1°C and in permeable kraft paper and kept in non-controlled environment. At the beginning of the storage and every three months the seed quality (germination and vigor tests), emergence rate index, height, dry mass and damping of plants in pre and post-emergence (in contaminated substrate and mycelia-free substrate) were analyzed. Both storage conditions as well as the fungicide treatments preserved the germination and seed vigor . In the infested substrate, seedling emergence was favored by fungicides, but in post-emergence, fungicides alone did not control the damping off caused by R. solani. Symptoms of damping off were not observed in the clean substrate. The results showed that the fungicide treatments may be used to pretreat papaya seed for long-term storage and commercialization.