RESUMEN
Spray-drying technique is widely used in the production of powder from fruit juices. Carrier type and inlet temperature are two major factors that influence drying efficacy and powder quality. In this study, barberry juice (Berberis vulgaris L.) was powdered using 12% (w/v) maltodextrin with 4-7 and 16.5-19.5 dextrose equivalents (DEs) at two different inlet temperatures at 130 and 150 °C. Moisture content, bulk density, hygroscopicity, color, total anthocyanin content (TAC), microstructure, glass transition temperature and the X-ray diffraction of the prepared powders were investigated. The inlet temperatures and the utilization of maltodextrin with different DEs as the carrier agent, had different effects on the physicochemical properties of the prepared powders. By increasing the inlet temperature, the moisture content decreased while hygroscopicity increased. At inlet temperature of 130 °C, powders prepared with lower maltodextrin DEs had higher moisture content and bulk density, but lower hygroscopicity (p < 0.05). The SEM result demonstrated that, a decrease in color of the powder by increasing the inlet temperature. Darker particles with higher a* values and total anthocyanin contents (4.68 mg/g) were obtained when a larger amount of maltodextrin with lower DEs was utilized. At the lower inlet temperature, the powder particles had smoother surfaces. The glass transition temperature of the powders ranged from 47.1 to 54 °C based on different inlet temperature and DEs as well as moisture content. The amorphous surfaces of the dried particles were verified via X-ray diffraction profiling. Overall, applying different DEs in combination and lower inlet temperature led to the more appropriate physical and functional properties to the barberry powder. The TAC significantly depended upon the carrier agent, the inlet air temperature, and the interaction between the two variables.
RESUMEN
The aim of the present investigation was to explore the possibility of developing a fruit snack formulation based on dried fig powder and chocolate-coated. Dried Fig (Ficus carica L.) powder with a maximum particle size of 354 µm and the lowest compaction force was formulated as the core. Persian gum was prepared at the concentrations of 1.5, 2 and 2.5% and xanthan gum was prepared at the levels of 0.25, 0.39 and 0.54% as the middle layer to the coating of the core. Regarding rheological assessments, sugar-free chocolate containing 29.3% isomalt was selected for the coating of the outer chocolate shell in the entitled snack. Textural analysis showed that coating of the core with hydrocolloids decreased hardness and adhesiveness of the samples (p < 0.05). It was also observed that increasing the xanthan gum and Persian gum concentration led to the reduction of adhesiveness in the snacks (p < 0.05). Coating of cores with hydrocolloids resulted in lower thickness of the chocolate outer shell, as well (p < 0.05). Results of the sensory evaluation tests demonstrated that, the samples with hydrocolloid coating were the most preferred ones by the panelists.