Effect of solar drying methods on total phenolic contents and antioxidant activity of commonly consumed fruits and vegetable (mango, banana, pineapple and tomato) in Tanzania

Mongi, Richard J.; Ndabikunze, Bernadette K.; Wicklund, Trude; Chove, Lucy M.; Chove, Bernard

doi:10.5897/ajfs2015.1232

Cited by 8 publications

(2 citation statements)

References 39 publications

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“…However, there were no measurements taken at night for the consecutive drying days, wherein the partially dried grapes were left inside the dryer throughout the night of the consecutive drying days with an insulation blanket. At the end of each experiment, the dried products were packed in polyethylene bags and stored at −4 • C prior to laboratory analysis [58]. The dry matter of grapes was determined by placing the dried product in an oven for 12 h at 120 • C [31].…”

Section: Methodsmentioning

confidence: 99%

A New Mode of a Natural Convection Solar Greenhouse Dryer for Domestic Usage: Performance Assessment for Grape Drying

Tawfik,

Oweda,

Abd El-Wahab

et al. 2023

Agriculture

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It is known that the natural convection (NC) solar drying process is a simple and cheap method for drying foodstuffs, but it is not preferable for common users in the case of drying high-moisture content agro-products due to the slow rate of drying. Meanwhile, the forced convection (FC) drying process is most appropriate for such products, but its economic feasibility may be affected due to high initial and maintenance costs. Therefore, the present study proposed a controlled natural convection (CNC) drying mode using a solar greenhouse dryer (SGD) for drying grapes with two types of cover materials, glass and Plexiglas, through intermittent operation with a PV system to save energy as a simple and inexpensive domestic dryer instead of the common forced convection SGD and the conventional natural convection SGD. The obtained results of the new CNC drying mode using a Plexiglas SGD showed a higher drying rate than the NC drying mode and are close to the FC drying mode using the same cover material. The initial moisture content of the grapes was reduced from 5.91 g water/g dry matter to the final moisture content of 0.15 g water/g dry matter within 12 h and 15 h for the CNC and NC drying modes, respectively, using the Plexiglas SGD. Moreover, the thermal drying efficiency for the two mentioned drying modes was 12.5 and 9.7%, respectively. The Page model was found to be the most appropriate model to predict the kinetics of the SGD in all drying modes, regardless of the cover type. The new CNC drying mode using the Plexiglas SGD achieved the lowest cost per kg of dried grapes (1.26 USD/kg), the highest total saved costs over the lifespan of the dryer (USD 245.46) and the shortest payback period (1.08 years) compared to the other two dryers, NC-SGD and FC-SGD. Generally, the CNC-SGD had good performance over the NC-SGD because it is not affected by the fluctuation in the volume, velocity and direction of the inlet ambient air/wind during drying grapes as a high-moisture content product without external heating sources or complicated parts. Thus, the proposed drying system has the advantage in terms of simplicity, cheapness and saving energy compared to FC-SGD.

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Section: Methodsmentioning

confidence: 99%

A New Mode of a Natural Convection Solar Greenhouse Dryer for Domestic Usage: Performance Assessment for Grape Drying

Tawfik,

Oweda,

Abd El-Wahab

et al. 2023

Agriculture

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“…Dried old leaves with using the oven produces antioxidant activity with the highest water content, total phenol, total flavonoid, and specific total tannins (Widarta & Wiadnyani, 2019). Greater degradation can occur not only due to polyphenol oxidase but also due to long heating time (Richard et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

The combination tea of corn silk (Zea mays L.) and rosella flowers (Hibiscus sabdariffa L.): Antioxidant levels using different drying methods

Ulmillah

Suri

Kamelia

et al. 2022

Inornatus Biol. Educ. J.

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Corn silk and rosella flowers are plants whose utilization can still be developed, especially in the food sector. The secondary metabolites found in both plants serve as a source of natural antioxidants to combat free radicals. This study aims to examine the effect of variations in drying methods on the antioxidant activity content of a combination tea of corn silk and rosella flower. Antioxidant level test using the DPPH method. Analysis of antioxidant data in the form of determining the IC50 value using probit linear regression analysis. The study results show that drying using the oven method has an IC50 of 83 ppm while drying in the sun has an IC50 of 121 ppm. Research findings indicate high antioxidant levels in a combination of corn silk and rosella flower tea through oven drying and moderate antioxidants in direct drying in the sun.

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The application of solar drying process for the valorisation of papaya fruit

Pacifico

Gara

Stellari

et al. 2022

Eur Food Res Technol

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Effect of solar drying methods on total phenolic contents and antioxidant activity of commonly consumed fruits and vegetable (mango, banana, pineapple and tomato) in Tanzania

Cited by 8 publications

References 39 publications

A New Mode of a Natural Convection Solar Greenhouse Dryer for Domestic Usage: Performance Assessment for Grape Drying

A New Mode of a Natural Convection Solar Greenhouse Dryer for Domestic Usage: Performance Assessment for Grape Drying

The combination tea of corn silk (Zea mays L.) and rosella flowers (Hibiscus sabdariffa L.): Antioxidant levels using different drying methods

The application of solar drying process for the valorisation of papaya fruit

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