Aplicação de diferentes métodos de secagem para obtenção de macaúba (Acrocomia aculeata) em pó

• Autor(a) principal: Oliveira, Dalany Menezes
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1434
• topic: Acrocomia aculeata; Secagem; Liofilização; ß-caroteno; Macaúba; Suplementação alimentar; Brasil.; Acrocomia aculeata; Drying; Lyophilization; beta-carotene; Macaúba; Supplementary feeding; Brazil.; Ciências Agrárias; Ciência e Tecnologia de Alimentos

Grugru palm (Acrocomia aculeata (Jacq.) Lodd. Ex Mart.) is native to the savannas, open woodlands and 'cerrados' in tropical America. Several products can be obtained from such palm, especially the fruit pulp with great nutritional potential once it is a natural source of ß-carotene, vitamin A and minerals. Grugru palm fruits can be consumed fresh or in powder form, they can also be used as raw material for formulations many products formulations. The powder can be obtained by different drying techniques, but some of these processes cause a large quality loss (nutritional and sensory) in the final product. For this reason, knowing the properties of the grugru palm pulp and powder is important for adding value to the regional fruits and approaching the drying processes for better conservation, development of products and preparation of various types of food. AIMS. Application of two drying processes, lyophilization and oven dehydration in order to obtain grugru palm powder, carry out physical and hysicochemical evaluations, determine bioactive components and both pulp and powder hygroscopic behavior to finally evaluate the stability of quality parameters for the dehydrated product stored for 120 days in different packages. The grugru palm fruits were harvested in the Araripe Plateau of Cariri area, State of Ceara, Brazil, and then taken to the Laboratory of Food Quality Control and Drying of Federal University of Ceará (UFC) the fruits were selected according to both ripeness and sanity rates to be soon sanitized and peeled, the pulp was then set apart by the use of a knife and stainless steel. All the obtained pulp was homogenised, grinded and divided in plastic packages containing 100g pulp. Initially, the product characterization was conducted concerning respiratory rate, physical, chemical and mineral analysis. Later on, the analyses on the pulp were performed, handled to form two types of pulp: integral pulp (IP) and pulp with 8% maltodextrin (MP). Four grugru palm powders were prepared using the following processes: oven drying with air circulation at 65° C for 25 hours, without maltodextrin (T1) and with 8% of maltodextrin (T2); lyophilization for 25 hours, without maltodextrin (T3) and with 8% of maltodextrin (T4). Physical analyses were conducted on: water activity, color, adsorption isotherms, hygroscopicity and degree of caking; Physcochemical analyses were conducted on: moisture, pH, tritable acidity, soluble solids; Bioactive components: total phenolic, yellow flavonoids, vitamin C, ß-carotene and vitamin A. While studying the stability of quality parameters, each treatment was placed in different packages: plastic - P; laminated - L; laminated and vacuum closed - LV. Subsequently, the packages were stored at room temperature (± 25° C) for 120 days and analyzed every 30 days for the following determinations: moisture, water activity, color, ß-carotene, total phenolics and yellow flavonoids. Data were statistically analyzed through the analysis of variance (ANOVA), the differences between the averages were determined by the Tukey test at 5% probability. The fresh fruit evaluation revealed a respiration rate of 74.45 ml CO2.kg-1. h-1. High levels of sugars, soluble solids, pH, aw, lipids and carotenoids were found; however, the pulp showed low levels of acidity, moisture and ashes. Potassium (K) presented the highest content, followed by magnesium (Mg) and calcium (Ca); zinc (Zn) showed the lowest content. The results also showed high contents of ß-carotene and vitamin A, high levels of water activity and soluble solids, low level of moisture and acidity in the grugru palm pulp, characterizing it as a sweet product. The pulps in this study showed an orange color, and the IP showed a more intense orange color than that from MP. The T3 and T4 treatments presented the highest levels of the bioactive compounds: phenolics, vitamin C, ß-carotene and vitamin A, indicating that lyophilization was better in holding these compounds. However, both T1 and T2 levels of flavonoids showed higher values than those of T3 and T4. The best treatment in reducing moisture and water activity (aw) was T3, but all drying methods reduced moisture and aw levels, thus providing the inhibition of microbial growth. The T2 powder showed the darkest L* parameter, and the chromaticities a* and b* of T3 presented the most saturated yellow color followed by T4, revealing more attractive colors. The adsorption isotherms results showed that all models studied were fitted to the grugru palm powder dehydrated in oven and lyophilization. The adsorption isotherms were classified as Type III. The values for hygroscopic behaviors were 6.39 and 5.17% and for degree of caking were 3.11 and 0.03% for T1 and T2, respectively. The values for hygroscopic behaviors were 7.68 and 6.86% and for degree of caking 0.33 and 0.09% for T3 and T4, respectively. The GAB model was the best at representing isotherms behavior in T1 and T3, and the Oswin model in T2 and T4. For stability study on bioactive compounds and the quality parameters for grugru palm powder analyzed each 30 days during 120 days of storage at room temperature (± 25° C), the following results were obtained: the moisture content and water activity for all treatments and packages presented a gradual increase, except for water activity in T1 and T2 packed in LV. At the end of 120 days of storage, all treatments stored in plastic bags (P) and T1 stored in laminated packs surpassed the maximum moisture allowed by the legislation. In the color evaluation, T1 showed the most visible changes in brightness (L*) at the end of the experiment. The values for -a* coordinate were low, presenting a grayish hue for the powder; this coordinate showed no significant decrease during the storage period. The chromaticity +b* showed a yellow hue for the powder for all treatments, being T3 and T4 more saturated than T1 and T2. The dehydration method affected the content of ß-carotene: T3 and T4 ß-carotene concentrations were higher than those from oven dehydration (T1 and T2); another factor that influenced the ß-carotene content was the addition of maltodextrin. During the storage period, the ß-carotene has degraded regardless of both treatment and packaging. The phenolic contents presented a decrease at the end of the storage period. All treatments showed a slight fluctuation in the flavonoids values and a raise at the end of 120 days of storage. The grugru palm fruit has a high respiratory rate, therefore the pulp processing is recommended in order to increase the product shelf life. Grugru palm pulp proved to be a sweet fruit, presenting low acidity, orange color and excellent levels of bioactive components, particularly the levels of ß-carotene. The adsorption isotherms of grugru palm powders can be classified as Type III. This powder is regarded as a nonhygroscopic and non-caking product. The best drying process in this study was lyophilization. The best conservation of grugru palm powder at room temperature (± 25° C) is lyophilization without maltodextrin (T3) and storage in laminated and vacuum closed packages (LV). This way, grugru palm can be regarded as an alternative for food enrichment and supplement.