Search Results (2)

This study aimed to investigate the impact of ultrasonic pretreatment vacuum drying (UAVD) and temperature on drying kinetics and qualitative attributes of blood oranges in comparison to several drying methods: hot air drying (HAD), vacuum drying (VD), and freeze drying (FD). The drying kinetics and modeling, total phenolic content (TPC), antioxidant capability (assessed using DPPH and ABTS tests), individual phenolic profiles, vitamin C concentration, and color factors were meticulously examined. Drying times were recorded as 22.5 h, 12.5 h, and 9 h for HAD; 11.5 h, 9.5 h, and 8.5 h for VD; and 10 h, 8.5 h, and 7.5 h for UAVD at 50, 60, and 70 °C, respectively. The HAD, VD, and UAVD procedures were conducted at 50, 60, and 70 °C, resulting in reduced drying periods with increasing temperature. The integration of ultrasound markedly lowered drying durations. Eleven thin-layer drying models were utilized to recreate the drying process precisely. The D_eff values of the HAD, VD, and UAVD dried samples varied from 9.08 × 10⁻⁶ to 2.82 × 10⁻⁵ m²/s, from 2.60 × 10⁻⁵ to 2.96 × 10⁻⁵ m²/s, and from 2.20 × 10⁻⁵ to 2.99 × 10⁻⁵, respectively. Among the desiccated blood orange slices, the greatest total phenolic content (TPC) was observed in freeze-dried samples (131.27 mg GAE/100 g), followed by those dried using ultrasonic-assisted vacuum drying (UAVD) at 50 °C (128.77 mg GAE/g DM). Dried blood orange slices had a vitamin C content of 29.79 to 49.01 mg/100. The drying process substantially impacted the color parameters L*, a*, and b*. These findings highlight the efficacy of ultrasound-assisted drying in decreasing drying duration while improving the retention of bioactive components in blood orange slices. Full article

The choice of time/temperature combination is critical for ensuring microbiological stability and retaining the characteristic taste of dried blood orange slices. The aim of this study was to investigate the capability of hot air-drying technique to maintain the quality characteristic of dried blood orange slices stored in modified atmosphere packaging (MAP). Hot air-drying at 70 °C for 12 h preserved shrinkage without altering the longitudinal diameter, though thickness was significantly reduced, especially in samples with passive MAP. Increased hardness and masticability were noted due to water removal, with active MAP maintaining high hardness and colour integrity up to 100 days of storage (D100). Sensory analysis revealed differences in colour intensity and flavour between active and passive MAP-stored slices. Headspace solid-phase microextraction (HS-SPME) chromatography identified key chemical compounds contributing to aroma and flavour, highlighting the complex interplay between temperature, storage conditions, and volatile organic compounds production. The study demonstrates that drying combined with MAP storage enhances organoleptic qualities and nutritional value, offering a method to produce a healthy, tasty, and visually appealing snack. Full article