Drying of olive leaves in a geothermal dryer and determination of quality parameters of dried product

Helvaci, Huseyin Utku; Menon, Abhay; Aydemir, Levent Yurdaer; Korel, Figen; Akkurt, Gülden Gökçen

doi:10.1016/j.egypro.2019.02.065

Cited by 15 publications

(11 citation statements)

References 16 publications

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“…The main reason for this color preservation is the protection against solar irradiation of the solar tunnel dryer, so Kinetics of Drying Medicinal Plants by Hybridization of Solar Technologies DOI: http://dx.doi.org /10.5772/intechopen.89686 dehydrated plants are kept more similar to fresh ones. For this reason, it is preferable to dry in a closed and controlled environment, which is consistent with studies of Helvaci et al [46].…”

Section: Colorimetric Analysissupporting

confidence: 90%

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Kinetics of Drying Medicinal Plants by Hybridization of Solar Technologies

Téllez¹,

Téllez²,

Navarro³

et al. 2020

Current Drying Processes

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Historically, medicinal plants have always had an important place in medicine. Medicinal plants processing represents a great challenge, due to their compounds sensitive to the environmental conditions that surround and degrade them. Mostly of these plants require to be dry to preserve its safety and medicinal properties; therefore, for proper drying, it is necessary to use sustainable devices that protect the desirable characteristics of plants from direct radiation. In this work, the kinetics of dehydration of three medicinal plants are presented in an indirect solar dryer. In addition, the experimental results were adjusted to nine mostly used models, to estimate the drying conditions required to achieve a desired final moisture content. Modified Page and Page were the models with better fit to experimental results. Furthermore, a computational simulation of temperature evolution and distribution inside the dryer is presented. These results agree with those obtained experimentally.

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Section: Colorimetric Analysissupporting

confidence: 90%

“…The temperatures reached in the dryer with the hybridization of solar technologies remained stable during most of the day, with a variation between 45 and 50°C (Figures 3 and 12), which, as reported in the literature reviewed, are optimal to prevent the loss of important properties in vegetables and medicinal plants [46,50].…”

Section: Computational Analysismentioning

confidence: 78%

Kinetics of Drying Medicinal Plants by Hybridization of Solar Technologies

Téllez¹,

Téllez²,

Navarro³

et al. 2020

Current Drying Processes

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“…In their research, it was found that the depletion of TPC (arising from the increase in drying time) is potentially minimized with a drying temperature of 50 • C and air velocity of 1 m/s. An optimized geothermal drying approach investigated by Helvaci et al [29] described that drying at a temperature of 50 • C and air velocity of 1 m/s is effective in lessening the depletion of polyphenols in dried olive leaves. Nourhene et al [30] investigated the drying kinetics of olive leaves from four Tunisian cultivars through solar drying (using an indirect forced convection) and reported that the rate of moisture diffusivity (ranging from 2.95 × 10 −10 to 3.60 × 10 −9 m 2 /s) relies on drying temperatures as well as cultivar variations.…”

Section: Typical Preprocessing Means Applicable To Olive Leave Extraction 21 Dryingmentioning

confidence: 99%

Roles of Drying, Size Reduction, and Blanching in Sustainable Extraction of Phenolics from Olive Leaves

Markhali

2021

Processes

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It is now known that olive leaves contain a sizable portion of polyphenols and there is much research highlighting that these natural ingredients favorably exhibit bio-functional activities. In this regard, many studies have focused on the exploration of optimum conditions involved directly in the extraction process. These investigations, while being highly valuable, may somewhat cast a shadow over other contributing factors such as those involved in the preprocessing of leaves, including size reduction, drying, and blanching. The use of these unit operations under appropriate conditions, together with other benefits, potentially exert improved surface area, homogeneity, and diffusion/mass transfer which may help develop the liberation of target bio-compounds. The research work in this area, particularly size reduction, is relatively limited. Although in various experiments they are incorporated, not many studies have focused on them as the main predictor variables. The performance of further research may help ascertain the magnitude of their effects. Consideration of the operational parameters in preprocessing step is equally important as those in the processing/extraction step that may comparably influence on the extraction efficiency. This review provides an overview of the potential roles of drying, size reduction, and blanching in the extraction efficiency of phenolics from olive leaves.

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“…In general, OTL are constituted by both low molecular weight substances and more complex molecules. Constituents belonging to the first group can be removed by washing with water or organic solvents: extracts, with a fundamentally organic nature, such as aliphatic and aromatic hydrocarbons; alcohols; phenols (especially oleuropein, hydroxytyrosol, and flavonoids as major compounds [1,8]); aldehydes; ketones; phenolics acids (vanillic, p-coumaric, and ferulic acids); waxes; glycerides and nitrogen compounds; as well as ashes, constituted by mineral substances of calcium, potassium, and magnesium, which are mainly in the form of carbonates, oxalates, and silicates. On the other hand, the structural macromolecules making up the cell wall consist mainly of cellulose, hemicellulose, and lignin, although there are also other molecules such as pectins, glycoproteins, suberine, and cutin.…”

Section: Introductionmentioning

confidence: 99%

Acid Hydrolysis of Olive Tree Leaves: Preliminary Study towards Biochemical Conversion

Mateo

Barbanera

et al. 2020

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Olive tree leaves, an abundant agricultural by-product without enough industrial market outlets, are presented in this study as a relevant resource of available carbohydrates to be chemically treated for monomeric sugar production. Characterization of two main granulometric fractions is the starting point for testing the specific effect and the relevance of three main factors (time, temperature, and sulfuric acid concentration) on diluted acid hydrolysis with respect to oligosaccharides, simple sugars, and fermentation inhibitory compounds production. The selected conditions (100 ∘ C, 90 min, and 6% w/w H 2 SO 4 ) to perform the small scale hydrolytic process, considering response surface methodology (2 3 factorial design with center points), implied production of acetic acid and hydroxymethylfurfural in concentrations not exceeding 1.10 kg m − 3 and 0.25 kg m − 3 , respectively. Thus, these experimental conditions were the reference framework to evaluate the effect of a meaningful scaling stage in a hydrolysis reactor, considering kinetic parameters based on hydrolysis rates and d-glucose and d-xylose generation.

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Drying of olive leaves in a geothermal dryer and determination of quality parameters of dried product

Cited by 15 publications

References 16 publications

Kinetics of Drying Medicinal Plants by Hybridization of Solar Technologies

Kinetics of Drying Medicinal Plants by Hybridization of Solar Technologies

Roles of Drying, Size Reduction, and Blanching in Sustainable Extraction of Phenolics from Olive Leaves

Acid Hydrolysis of Olive Tree Leaves: Preliminary Study towards Biochemical Conversion

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