Effects of convective dehydration and subsequent storage in modified atmosphere on Sicilian red oranges.
Among the various processing techniques also for citrus fruits, dehydration and, in particular, convective hot air dehydration is spreading lately. This is seen not only as a technique for extending the shelf life of food, but also as a means of increasing its value. Dried fruits have a very high total energy, fibers and nutrients density.
The purpose of a recent study, carried out by a group of Italian researchers (Roppolo et al., 2023), was to analyse the effects of convective drying and subsequent modified atmosphere (Map) storage on the physico-chemical (weight loss, consistency, color, browning index and citrus color index), microbiological (total mesophile bacteria, psychotrophic bacteria, yeasts, molds, Enterobacteriaceae, Listeria spp. and L. monocytogenes), nutraceutical (mineral and vitamin composition) and sensory (consumer test) properties of red orange fruits.
In particular, for this analyses oranges of the varieties Moro, Tarocco and Sanguinello, deprived of flavedo and albedo, were cut transversely into 0.5 cm thick slices, and subjected to a temperature of 70 °C for 12 h and then stored in 100% N2 MAP for 3 months. In conclusion, the results indicate a good tendency of the fruit to dehydrate: The proposed process allows the production of an innovative product to be consumed as or as a basis for other food preparations.
Impact of hot-air dehydration and modified atmosphere storage on the quality of mango fruit.
Being a climateric fruit, fresh mango has a limited shelf-life due to the high respiration rate, high production of ethylene gas and diseases that cause the post-harvest loss of valuable nutrients and the decline of the market value. Therefore, the aim of a recent study carried out by a group of Italian researchers (Tinebra et al., 2023), was to develop a simple technological process, capable of obtaining a dried mango that best maintains the nutritional characteristics of the fresh fruit.
To limit the waste of produce, fruit commercially defined as “non-compliant” or “scrapped” of the Tommy Atkins cultivar at two different ripeness levels (Green and Mature), were used; they were dried using a hot air stream and stored in modified atmosphere with a mixture containing 100% N2. To identify the right time/temperature combination, tests were carried out using two different temperatures, 50 and 70°C. The fruit properties were best preserved at 70°C for a period of 12 h.
Qualitative, sensory and microbiological analyses were performed over a ten-day time interval. The resulting product is characterized by a pleasing structure and colour, high mineral and fiber content, intense taste and aroma, typically mango, and microbiologically healthy, confirming the validity of the processing method used. Finally, the application of modified atmosphere allowed to best maintain the dried fruit properties for a long period of storage.
References
Roppolo et al., Acta Italus Hortus – Riassunti dei lavori XIV Giornate Scientifiche SOI, Torino, 21-22 giugno 2023, pp. 265.
Tinebra et al., Acta Italus Hortus – Riassunti dei lavori XIV Giornate Scientifiche SOI, Torino, 21-22 giugno 2023, pp. 252.
