Determination of Thermal Properties of Coffee Beans at Different Degrees of Roasting

Cardoso, Danilo Barbosa; Andrade, Ednilton Tavares de; Calderón, Renso Alfredo Aragón; Rabelo, Mariane Helena Sanches; Dias, Camila de Almeida; Lemos, Isabela Ávila

doi:10.25186/cs.v13i4.1491

Cited by 12 publications

(7 citation statements)

References 14 publications

(18 reference statements)

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“…The specific heat values seem to be in accordance with those found by Cardoso et al (2018), Burmester et al (2011), however, the results can also be affected by the calculation model since the regression terms can change (Pérez‐Alegría et al, 2001).…”

Section: Resultssupporting

confidence: 88%

Improving the drying performance of parchment coffee due to the newly redesigned drying chamber

Duque‐Dussán

Banout

2022

J Food Process Engineering

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The Colombian coffee growers face many complications when using traditional open-sun drying techniques such as post-harvest process delays or incomplete grain dryness because of climate conditions. Therefore, local workshops began fabricating low-capacity dryers simulating the industrial equipment working principles. One of the most commercialized units is a triple tray rectangular-shaped dryer with a 31.25 kg capacity of dry parchment coffee per batch, providing the issue with an acceptable solution. However, it was redesigned into a circular shape holding a lower grain bed thickness and a vertical air inlet with a diffusive tray. Both units were simulated using the Thompson and the Michigan State University grain drying mathematical models to obtain their theoretical drying time. Then, a computational fluid dynamics simulation was conducted, attaining the unit's drying air behavior, the circular dryer exhibited notable drying times reduction and even air distribution, optimizing the dryer's performance, representing a benefit for the coffee-growing farmers. Practical ApplicationsA cylindrical arranged coffee dryer with a vertical air inlet reduces the drying time of the grain, allowing a better rentability of the grower and improves the air distribution inside the equipment, meaning that the moisture removal will occur uniformly, safeguarding that the product's final moisture content meets the required conditions for safe storage.

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Section: Resultssupporting

confidence: 88%

Improving the drying performance of parchment coffee due to the newly redesigned drying chamber

Duque‐Dussán

Banout

2022

J Food Process Engineering

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“…Then the total heat flux ("charge") on each component of the boundary will be related to the boundary temperatures via capacitance matrix. We note in passing that there is so-called "thermal capacitance matrix" [41,42], unrelated to the geometric matrix defined here.…”

Section: Resultsmentioning

confidence: 99%

Capacitance Matrix Revisited

Smolić¹,

Klajn²

2021

PIER B

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The capacitance matrix relates potentials and charges on a system of conductors. We review and rigorously generalize its properties, block-diagonal structure, and inequalities, deduced from the geometry of system of conductors and analytic properties of the permittivity tensor. Furthermore, we discuss alternative choices of regularization of the capacitance matrix, which allow us to find the charge exchanged between the conductors having been brought to an equal potential. Finally, we discuss the tacit approximations used in standard treatments of the electric circuits, demonstrating how the formulae for the capacitance of capacitors connected in parallel and series may be recovered from the capacitance matrix.

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“…C for powdered sugar. 22,23 Higher heat conductivity of ground coffee particles might lead to better polymer melting during the sealing process. This can supply good encircling around the particles and results in higher seal strength.…”

Section: T-peel Testmentioning

confidence: 99%

Effects of process parameters and solid particle contaminants on the seal strength of low‐density polyethylene‐based flexible food packaging films

2021

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Seal strength is a key indicator of heat seal quality in flexible packaging. In this study, the effect of seal bar geometry, material composition and food particle contamination on the seal strength of widely used low‐density polyethylene (LDPE)‐based compound films was examined. Additionally, the maximum level of allowable solid food particle contamination was determined for ground coffee particles and powdered sugar. The results showed that adding metallocene LLDPE compound decreases seal initiation temperature (SIT) and increases overall seal strength. Also, changing seal bar geometry from flat to grooved bar with 0.56‐mm pitch height enhanced the seal strength significantly. Moreover, pressure mapping and T‐peel tests at SIT pointed out that grooved bars alter the pressure distribution and first contact points through the seal surface. Contamination of ground coffee particles at the seal interface as occurs during the packaging process when a powdery product is dropped in a package did not affect the seal strength up to 10 g/m2 at 0.5‐s dwell time. Above that amount, seal strength dropped dramatically. In the case of powdered sugar, threshold contaminant level was 2 g/m2 at 0.5‐s dwell time. Consequently, it has been revealed that knowing the type and the amount of contaminant during the food packaging process is important to maintain the seal quality, to find optimum process values between dosing and filling and to choose the right seal bar design because they can have a critical influence, especially at seal initiation phase.

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Determination of Thermal Properties of Coffee Beans at Different Degrees of Roasting

Cited by 12 publications

References 14 publications

Improving the drying performance of parchment coffee due to the newly redesigned drying chamber

Improving the drying performance of parchment coffee due to the newly redesigned drying chamber

Capacitance Matrix Revisited

Effects of process parameters and solid particle contaminants on the seal strength of low‐density polyethylene‐based flexible food packaging films

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