No abstract

De modo geral, a sua floração se dá de agosto a novembro, coincidindo com o período das chuvas, com pico em setembro, já a frutificação ocorre de novembro a fevereiro ( ALMEIDA et al., 1998). A sazonalidade é um fator que limita a comercialização e o acesso da população ao pequi.A desidratação do pequi seria uma excelente alternativa para conservar e garantir o comércio do fruto em períodos de entressafra. A liofilização constitui um processo de desidratação em que a água do produto submetida ao prévio congelamento passa diretamente do estado sólido para o gasoso (sublimação), em condições especiais de temperatura e pressão. Para que isso ocorra, é necessário que a pressão de vapor e a temperatura da camada de gelo sublimável estejam abaixo do ponto tríplice da água. O vapor libertado pela sublimação é captado pelo condensador, que deve estar a uma temperatura mais baixa do que o produto a ser liofilizado (KING, 1988). Krokida e Philippoulous (2006) avaliaram os efeitos da secagem convencional e da secagem por liofilização no flavor de maçãs. Os resultados mostraram que a secagem por liofilização garantiu produtos com qualidade de flavor altamente superior àqueles secados por método convencional. AbstractIn this study, food powders obtained from the freeze-dried pequi (Caryocar brasiliense Camb.) pulps (internal mesocarp) were developed by adding alcohols (ethanol and isopropyl alcohol) in concentrations of 0, 5, and 10% and sugars (sucrose and fructose) in concentrations of 0, 5, and 10%. Microstructure analyses by photonic microscopy of the freeze-dried powders were used to evaluate the degree of crystallization. Color analyses using a Minolta colorimeter and the total carotenoid values using a spectrophotometer were also done. The results show that treatments with a sucrose and ethanol combination presented the formation of crystalline structures and the best preservation of the carotenoid contents. The higher the concentration of the alcohol added in the pre-treatments, the better preserved the caretenoids in the freeze-dried powders became. Treatments with fructose and isopropyl alcohol produced freeze-dried powders that were typically amorphous presenting caking phenomena. Pre-treatments with sucrose and ethanol are the solution to these problems since they are able to produce freeze-dried powders of the pequi pulp with physical chemical and microstructural stability.

a b s t r a c tPeki (Caryocar brasiliense Camb.) is a Brazilian fruit with an extremely high b-carotene content, but the b-carotene is unstable under dry storage conditions. This work reports on the product development and stability of freeze-dried peki fruit pulp. Freeze-dried products were made by adding alcohols (ethanol and isopropyl alcohol; at concentrations of 0, 5 and 10 mL/100 mL of extract) and sugars (sucrose and fructose; at concentrations of 0, 5 and 10 g/100 mL of extract) to the peki fruit pulps followed by freezedrying. Scanning electron microscopy was used to analyze the microstructure of the freeze-dried products by visualizing the crystallized forms. The product hardness and total carotenoid content following the different treatments were measured using a texture analyzer and a spectrophotometer, respectively. The stability of these foods was evaluated by their water sorption during their storage in various relative humidity environments at 25 C. There were characteristic differences in their hygroscopic behaviors. The pretreatment with sucrose and ethanol improved the freeze-dried product and yielded a lower number of collapsed structures. Changes during the storage were observed. The pulp pretreated with sucrose was amorphous and metastable, but the drying process was accelerated by the presence of alcohol (mainly ethanol), which resulted in protected structures without any sign of collapse.