Minimization of the adverse environmental effects of discarded onions by avoiding disposal through dehydration and food-use

FABANI, MARÍA PAULA; ROMAN, MARÍA CELIA; RODRIGUEZ, ROSA A.; MAZZA, GERMÁN D.

JOURNAL OF ENVIRONMENTAL MANAGEMENT

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2020 vol. 271 p. 1 - 11

0301-4797

Onion is a commonly used vegetable in the Cuyo Region,Argentina, and important in the world global vegetable production ranking. Productionlevels often exceed immediate markets of fresh sale, and excesses, althoughstill edible, are currently discarded (mostly incinerated and disposed in landfill,creating numerous environmental hazards). To minimize these adverseenvironmental problems, this research investigates upgrading the discardedproducts by dehydration, hence guaranteeing their ultimate food-use. Thedehydration process of discarded onion cv. CrioulaRoxa was hence studied at 60 and 70°C, temperatures selected to maintain themain physicochemical characteristics of the onions, while also creating optimumheat and mass transfer coefficients while significantly reducing the energyconsumption and CO2 emissions. When using an electrically-heated convective dryer, theSpecific Energy Consumption (SEC) values and the CO2 emissionsduring dehydration at 70ºC are 738.89 kWh.kg-1 and 264.74 kg of CO2kg-1, respectively. These values are only 41.61 kWh.kg-1 and2-4 kg of CO2 kg-1 if a solar dryer is applied. The thermaldiffusivities were 1.86´10-10m2 s-1 (dehydration) and 1.08´10-10m2 s-1 (rehydration), showing a weak effect of thedehydration process on the solid structure and properties.