Uso da irradiação e de revestimento comestível na conservação de pinhão [Araucaria angustifolia (Bertoloni) Otto Kutze] in natura e minimamente processado

Abstract

Pinhão is the seed Araucaria angustifolia, rich in carbohydrates with low glycemic index, minerals and vitamin C, as well as phenolic compounds present in the bark, which diffuse into the seed. However, this seed has a high degree of perishability and is affected by infestation of larvae, sprouting and fungi during storage, due to its high water activity, which hinders its commercialization. The objective of this study was to evaluate the conservation of in natura pinhão using gamma radiation/refrigeration, as well as minimally processed pinhão using edible coatings. In the first experiment, the in natura pinhões were submitted to radiation (1 kGy), also having a non-irradiated control, both samples were stored at room temperature and under refrigeration (4 °C). The pinhão were packed in high density polyethylene bags and evaluated during 90 days of storage for weight loss, acidity, reducing sugars, vitamin C, firmness, color, total phenolic compounds, antioxidant activity and microbiological analyzes. In general, the preservation by refrigeration, without the application of irradiation, resulted in better results in the conservation of in natura pinhão by reducing the loss of mass, the percentage of reducing sugars and enabling the obtaining of higher vitamin C content and antioxidant activity. However, the application of radiation on the pinhão associated with refrigeration caused, in general, the lowest counts of the evaluated microorganisms. In the second experiment, the pinhões were minimally processed and coated with chitosan, gelatin and chitosan/gelatin by the layer-by-layer technique. After, the pinhões were dried under forced ventilation, packaged in a polyethylene terephthalate package and stored at 4 °C for 10 days. The analyzes performed were weight loss, pH, reducing sugars, vitamin C, color, microbiological analysis and sensory analysis. Benefits were observed with the use of chitosan and gelatin coatings, especia ly when applied by the layer-by-layer technique. With the application of the chitosan/gelatin coating the best combination of results was obtained, mainly reduction of mass loss and inhibition of growth of fungi and aerobic psychrotrophic bacteria. A tendency of color maintenance, absence of thermotolerant coliforms and positive coagulase Staphylococcus were also obtained. The coating did not retard the maturation process, thus higher vitamin C contents were obtained. The coatings did not influence the taste and aroma of minimally processed pinhões. It is believed that these techniques can be used for seed conservation, encouraging their consumption.