Solar Dehydration of Sliced Onion

Elzubeir, Asim Osman

doi:10.1080/19315260.2013.802754

Cited by 8 publications

(2 citation statements)

References 2 publications

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“…Another usual option is the manufacture Solar 2022, 2 of jams and jellies, with addition of high amounts of sugar, resulting in a less healthy product. Dehydration is one of the oldest techniques of food preservation still widely used for preserving figs, grapes, or fish, in a passive and direct mode, despite it being time-consuming and the fact that food is often contaminated by dust, insects, fungi, and bacteria [3]. However, it lowers the cost of packaging, storing and transportation by reducing the final weight and volume.…”

Section: Introductionmentioning

confidence: 99%

Design of a Friendly Solar Food Dryer for Domestic Over-Production

Fernandes

Tavares

2022

Solar

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Solar drying is one of the many ways of efficiently making use of solar energy to meet the human demand for improved sustainability. In this study, we describe the construction and testing of two indirect solar dryer prototypes, especially designed for vegetables and fruits. The dryers had two compartments: a solar panel and a drying chamber. The dryers were mainly made of wood (Prototype 1) and styrofoam (Prototype 2) and both used recycled aluminum cans. The calculated yield of solar panels was 82% and 77% for Prototype 1 and 2, respectively. The drying tests performed with different fresh products showed that it was possible to dry all of them until less than 10% of their initial weight, at different times, depending on the type of product. As regards the apple slices, the solar dryers were able to remove 95.7% and 95.0% of initial moisture on a wet basis for Prototype 1 and 2, respectively. Comparative tests were conducted with an electric commercial dryer using the same product to explore the drying dynamics and costs. The cost of the final dry product, excluding the purchase of fresh goods, was 6.83 €/kg for the electric dryer, 1.78 €/kg for Prototype 1 and 1.72 €/kg for Prototype 2. Dehydrated apple slices are currently available on the market for around 34.50 €/kg. Our solar dryers can dry quality products at a very low cost for their entire life span, which allows them to compete with electric systems to prevent food waste in a cheaper and environmentally friendly way.

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Section: Introductionmentioning

confidence: 99%

Design of a Friendly Solar Food Dryer for Domestic Over-Production

Fernandes

Tavares

2022

Solar

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“…At a temperature of 40 C and operating time of 120 min, infrared drying reduced the moisture content of fresh onion feed by~86%, whereas the moisture content removal was 97% in this study. In this study, the drying conditions applied were superior than solar dryers working at a temperature of 30 C and relative humidity of~60% (Elzubeir, 2014). Solar dryers require 13 h to dry onion slice from 83% to 20% wet basis.…”

Section: Resultsmentioning

confidence: 89%

Effects of drying temperature and relative humidity on the quality of dried onion slice

Sasongko

Hadiyanto

Djaeni

et al. 2020

Heliyon

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Onion, a very common season ingredient, is useful as an antioxidant and optimal conditions are required for its drying while ensuring the best quality is retained. This study evaluated the effect of drying temperatures and relative humidity on both drying rate and onion quality. Onions with an average diameter of 20.125 ± 0.025 mm were peeled and sliced into a thickness of 1.233 ± 0.029 mm. They were then dried for 120 min under various temperatures ranging from 40 to 70 °C. Both moisture content and total phenolic compounds were measured and analyzed as responses, and the data obtained were used for estimating the kinetic parameters of drying rate and total phenolic compounds degradation. The results show that the drying kinetics followed Fick's model. Moreover, the total phenolic compounds degradation can be properly expressed using a first-order reaction model, and the optimization using response surface method revealed that the optimum conditions of onion slice drying were achieved at 49.6 °C and relative humidity of 0.65%. These conditions can significantly reduce drying time with phenolic compounds retention of up to 96%.

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