CFD simulation of heat transfer and polyphenol oxidation during tea fermentation

Lian, Guoping; Thiru, A.; Parry, Andrew D.; Moore, Steve

doi:10.1016/s0168-1699(01)00184-3

Cited by 15 publications

(7 citation statements)

References 23 publications

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“…Greater bed thickness results in accumulation of heat in oxidizing leaves and actual temperature within the leaf bed is higher, which in turn leads to faster degradation of catechins. This is also supported by the findings of Lian et al (), where a significant temperature rise in oxidizing leaves along bed thickness was reported. However, the effect of bed thickness on degradation of catechins is not very pronounced and residual levels of catechins are only slightly reduced at greater bed thickness.…”

Section: Resultssupporting

confidence: 89%

“…The amount of catechins is reduced to less than 10% of its original content in black tea (Wang, Provan, & Helliwell, ). TF are formed by enzymatic oxidation and condensation of catechins with di‐ and trihydroxylated B rings (Kusano, Matsuo, Saito, & Tanaka, ; Lian, Thiru, Parry, & Moore, ). Level of TF and their fractions (Panigrahi, Bhol, & Das, ; Qu et al, ; Wright, Mphangwe, Nyirenda, & Apostolides, ), catechin fractions and ratio between polyphenoloxidase and catechins (Lopez, Thomas, Pius, Kumar, & Muraleedharan, ; Saravanan, John, Raj Kumar, Pius, & Sasikumar, ) have been considered as reliable black tea quality parameters.…”

Section: Introductionmentioning

confidence: 99%

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Analysis and modeling of major polyphenols during oxidation in production of black tea

Das

Samanta

Datta

2019

J Food Process Preserv

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Analysis of four different catechins, four theaflavins (TF), and thearubigin (TR) in oxidizing macerated CTC (crush–tear–curl) and rolled orthodox leaves of TV25 clone was done. Tea leaves were oxidized at different air temperatures (20, 25, 30, and 35°C) and thickness of oxidizing leaf bed (2 and 5 cm). Rate of depletion of catechins was modeled using Michaelis–Menten equation. Depletion of dihydroxylated catechins (EC, ECG) was found to be more affected by change in air temperature than trihydroxylated catechins (EGC, EGCG). Amount of maximum total TF at different temperatures was in the range of 1.19%–1.3% for CTC‐macerated leaves and 0.33%–0.43% for rolled orthodox leaves. Quadratic and linear regression equations, developed to model the change in TF and TR contents, respectively, were good fit. Bed thickness does not have any significant effect on TF content in both CTC and orthodox leaves as revealed from ANOVA. Practical applications Oxidation or fermentation of macerated leaves is a crucial step in black tea processing that needs to be carefully monitored. Tea processing facilities maintain only air humidity level during fermentation. Air temperature is also an important factor affecting the degradation of catechins and formation of different pigment compounds. Optimum amount of unoxidized catechins and oxidized compounds TF and TR affects the quality of final product. Modeling of catechin, TF, and TR contents in oxidizing leaves will help to manipulate processing conditions such as air temperature, duration, and bed thickness to produce good quality black tea.

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Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Analysis and modeling of major polyphenols during oxidation in production of black tea

Das

Samanta

Datta

2019

J Food Process Preserv

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“…In another study, modeling of aerobic and anaerobic fermentation has been performed to produce ethanol in an agitated reactor and mass fractions of glucose, ethanol, cellulose–enzyme complex, and cells in the reactor were calculated using the contour plots 27. CFD has also been extensively used in food industry with applications in production and post‐production techniques like drying, baking, tea production, brewing, refrigerating, sterilization, ventilation, storage, and transportation 28–34…”

Section: Microbial Fermentation And/or Mammalian Cell Culturementioning

confidence: 99%

Review of Computational fluid dynamics applications in biotechnology processes

Sharma

Malhotra

Rathore

2011

Biotechnology Progress

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Computational fluid dynamics (CFD) is well established as a tool of choice for solving problems that involve one or more of the following phenomena: flow of fluids, heat transfer,mass transfer, and chemical reaction. Unit operations that are commonly utilized in biotechnology processes are often complex and as such would greatly benefit from application of CFD. The thirst for deeper process and product understanding that has arisen out of initiatives such as quality by design provides further impetus toward usefulness of CFD for problems that may otherwise require extensive experimentation. Not surprisingly, there has been increasing interest in applying CFD toward a variety of applications in biotechnology processing in the last decade. In this article, we will review applications in the major unit operations involved with processing of biotechnology products. These include fermentation,centrifugation, chromatography, ultrafiltration, microfiltration, and freeze drying. We feel that the future applications of CFD in biotechnology processing will focus on establishing CFD as a tool of choice for providing process understanding that can be then used to guide more efficient and effective experimentation. This article puts special emphasis on the work done in the last 10 years.

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“…Key examples of this include computational fluid dynamics (CFD) modelling of porous media phenomena [2][3][4][5], basic theory on unsaturated flow in soils [6][7][8], the modelling of bioreactions themselves [9][10][11][12], studies on the importance of aeration and temperature in bioremediation [13][14][15][16][17], the modelling of in-situ remediation, for example of groundwater, [18,19] and modelling of ex-situ processes [20][21][22]. Recently, Li et al [23] developed a simple analytical model to compare with field trials of different aeration techniques considering the orientation of venting pipes and suction pressure from a winddriven fan.…”

Section: Previous Researchmentioning

confidence: 99%

Simulation of biopile processes using a hydraulics approach

Crapper

2009

Journal of Hazardous Materials

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CFD simulation of heat transfer and polyphenol oxidation during tea fermentation

Cited by 15 publications

References 23 publications

Analysis and modeling of major polyphenols during oxidation in production of black tea

Analysis and modeling of major polyphenols during oxidation in production of black tea

Review of Computational fluid dynamics applications in biotechnology processes

Simulation of biopile processes using a hydraulics approach

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