00 mg/100 g) and Af the ascorbic acid content after 55% degradation during storage ( Labuza & Schmidl, 1985). The results obtained were

statistically evaluated using the variance analysis (ANOVA) and the means compared by Tukey’s test using version 7.0 of the Statistica program. Fig. 1 shows the results obtained for moisture content. It can KRX-0401 nmr be seen that there was greater water absorption in the accelerated state (35 °C and 90% RH), increasing by about 4.7 times as compared to the product at zero time, whereas under environmental conditions, this increase was about 2.5 times. According to Arlindo et al. (2007), the hygroscopic characteristics of some foods depend mainly on their chemical composition and storage

conditions (air relative humidity), which explains the greater increase in moisture content under the accelerated conditions. Few papers can be found in the literature concerning the shelf life of dehydrated powdered products stored in controlled environments. Thus, the increase in moisture content of the product at the end of the experiment can be attributed to the permeability of the packaging materials, favouring the absorption of moisture from the environment of the controlled storage system. Powdery products have presented, in general, low moisture contents, in the 4–6% interval. In this

study, in the accelerated condition (35 °C) the product showed 6% of moisture content in 26 days VRT752271 datasheet FAD of storage; under these conditions, the vitamin C retention was 75% of initial value. In environmental conditions (25 °C), the same moisture content was obtained in approximately 49 days and the product showed 45% vitamin C retention (Fig. 1 and Fig. 3). Fig. 2 shows the results obtained for water activity of the powdered guavira pulp, indicating that, as for moisture content, the water activity increased during storage, being greater under accelerated conditions (0.680) than under environmental conditions (0.470). This difference can be attributed to the relative humidity of the air in the storage environment. According to Garcia, Padula, and Sarantopulos (1989) as cited by Gomes et al. (2004), the type of packaging material used for food products constitutes a barrier that impedes or hinders contact between the food and the external environment. Nevertheless the permeability of the packaging materials should be considered. Depending on the permeability rates of water vapour and oxygen, greater absorption of moisture can occur from the environment, consequently influencing the water activity and justifying the greater absorption of water under accelerated conditions.