Drying kinetics and effective moisture diffusivity of purslane undergoing microwave heat treatment

Demırhan, Elçin; Özbek, Belma

doi:10.1007/s11814-010-0251-2

Cited by 34 publications

(26 citation statements)

References 54 publications

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“…The purpose of a mass and energy transfer model in a food production process is to describe the physical process as accurately as possible [10,11]. Mathematical models are an important tool for minimizing operational problems in the simulation of roasting, such as product damage, high energy consumption, hardness, palatability, and creation of products with a non-uniform quality, among others [12,13]. Knowledge of dehydration kinetics is necessary for the design, optimization, and control of the process [14].…”

Section: Introductionmentioning

confidence: 99%

Kinetic Studies and Moisture Diffusivity During Cocoa Bean Roasting

et al. 2019

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Cocoa bean roasting allows for reactions to occur between the characteristic aroma and taste precursors that are involved in the sensory perception of chocolate and cocoa by-products. This work evaluates the moisture kinetics of cocoa beans during the roasting process by applying empirical and semi-empirical exponential models. Four roasting temperatures (100, 140, 180, and 220 °C) were used in a cylindrically designed toaster. Three reaction kinetics were tested (pseudo zero order, pseudo first order, and second order), along with 10 exponential models (Newton, Page, Henderson and Pabis, Logarithmic, Two-Term, Midilli, Verma, Diffusion Approximation, Silva, and Peleg). The Fick equation was applied to estimate the diffusion coefficients. The dependence on the activation energy for the moisture diffusion process was described by the Arrhenius equation. The kinetic parameters and exponential models were estimated by non-linear regression. The models with better reproducibility were the pseudo first order, the Page, and the Verma models (R2 ≥ 0.98). The diffusion coefficients that were calculated were in the order of 1.26 to 5.70 × 109 m s−2 and the energy activation for moisture diffusion obtained was 19.52 kJ mol−1.

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Section: Introductionmentioning

confidence: 99%

Kinetic Studies and Moisture Diffusivity During Cocoa Bean Roasting

et al. 2019

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“…The tender stems and leaves can be eaten raw, cooked or pickled. The leaves can be frozen or dried and stored for many years [12].…”

Section: Introductionmentioning

confidence: 99%

“…The reduction of water activity by moisture removal leads to significant reduction of weight and volume, minimizing packaging, transportation and storage costs [14]. Drying also, alters other physical, biological and chemical properties of foods [12]. Hot-air drying is one of the most frequently used operations for food dehydration [15].…”

Section: Introductionmentioning

confidence: 99%

Effect of Drying Methods on the Antioxidant Capacity, Color and Phytochemicals of Portulaca oleracea L. Leaves

Youssef¹,

Mokhtar²

2014

J Nutr Food Sci

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Portulaca oleracea is globally used both as a vegetable and as an herb for medical and therapeutic purposes; hence the need to investigate its phytonutrients. The aim of this study was to evaluate the effects of different drying methods (hot-air drying, microwave drying and freeze-drying) on the color, phytochemicals content and antioxidant capacity of purslane leaves. The fresh purslane leaves had high contents of total phenolics (1447.59 mg GAE/ 100 g) and flavonoids (5011.87 mg QE/ 100 g) on dry weight basis. They exhibited high antioxidant capacity (53.23% and 147.78 μmol trolox/ 100 g) measured by DPPH and ABTS assay, respectively. Chromatic coordinates (L * , a * and b *) as well as total color difference (ΔE) were affected by drying methods. Drying methods caused a significant decrease in total phenolics, total flavonoids and antioxidant capacity of purslane leaves. Drying by hot-air at 50ºC and freezedrying had the lowest adverse effects on antioxidant capacities of purslane leaves while microwave drying cannot be a competitive process for preserving antioxidants and antioxidant capacity of purslane leaves. The changes in the antioxidant capacity due to the drying methods were positively correlated with the content of phenolics (R 2 = 0.9043-0.9885). Therefore, it can be suggested that special care should be taken when processing method is selected for the exploration of purslane leaves.

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“…The reduction of water activity by moisture removal leads to significant reduction of weight and volume, minimizing packaging, transportation and storage costs (Okos et al, 1992). Drying also, alters other physical, biological and chemical properties of foods (Demirhan and Özbek, 2010). Hot-air drying is one of the most frequently used operations for food dehydration (Krokida and Maroulis, 1999;Youssef and Mokhtar, 2014).…”

mentioning

confidence: 99%