Proceedings of the 15th SLACAN - Latin American Symposium on Food Science and Nutrition

Umbu peel (UP) is a byproduct of the food industry rich in phenolic compounds, presenting high potential as a functional component in many food applications. The drying process can extend shelf-life and favor the application as flour in innovative products. The objective of this study was to dry UP in a conventional oven with renewal and constant air circulation at temperatures of 40, 60, and 80°C for 3 hours, being weighed every 5 min up to 60 min and every 10 min between 60 and 180 min. The response evaluated were the drying rate at the critical moisture level (DRCML), final moisture and total soluble phenolic content (TSPC). The initial moisture content of the sample was 82.20±0.05%, and the DRCML was 0.25 and 0.34kg of H2O/s.m2 for 60 and 80°C, respectively. This measure (DRCML) was not detected when the drying process was carried out at 40°C, since the drying curve presented a constant decline throughout the time. The final moisture content of the samples was 53.09±2.51, 36.88±1.74 and 10.36±1.01%, and the TSPC content was 2.27±0.04, 1.68±0.08 and 1.28±0.05gGAE/100g (db), for 40, 60 and 80°C (P<0.01), respectively. UP had an initial content of 4.17±0.10gGAE/100g (db) for phytochemicals, indicating a loss of 45.46, 59.56 and 69.26% for temperatures of 40, 60 and 80°C. Although the drying temperature at 40 and 60°C showed a lower loss of TSPC, the final moisture content was above what is stipulated for the best flour storage (<15%), thus demonstrating that drying at 80°C showed better performance. An additional time for samples dehydrated at lower temperatures could result in proper moisture content, but we believe TSPC loss also would increase. The drying process at 80°C showed a lower moisture content, resulting in a more stable product with representative TSPC content.
Funding agencies: CAPES; CNPq; FAPEMIG.