Interfacial rheology study of espresso coffee foam structure and properties

Piazza, Laura; Gigli, J.; Bulbarello, Andrea

doi:10.1016/j.jfoodeng.2007.06.001

Cited by 70 publications

(48 citation statements)

References 28 publications

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“…Formation of a stable gas-liquid interface is based on the diffusion and rapid adsorption of stabilisers on the newly formed surface (47). Optimum foaming capacity is reached with a reduced lag period and with rapid diffusion of the emulsifier toward the interface (19).…”

Section: Stability Of Gas-liquid and Liquid-liquid Interfaces: Interfmentioning

confidence: 99%

Interfacial rheology: An overview of measuring techniques and its role in dispersions and electrospinning

Pelipenko¹,

Kristl²,

Rošic³

et al. 2012

Acta Pharmaceutica

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Colloidal disperse systems represent the increasing number of modern delivery systems whose primary characteristic, a large interfacial area, causes thermodynamic instability. Therefore, the foremost challenge in dispersion design is the reduction of interface instability and an understanding of the behaviour of interfaces. Interfacial rheology is one of the most powerful tools for observing occurrences at the interphase. As previously mentioned, the stability of such systems is provided by the formation of a stable interfacial layer of surfactants around each dispersible particle. The stability of these systems can be improved by using more than one surfactant, but it must be kept in mind that different surfactants can have varying mechanisms of stabilisation, some of which can be mutually incompatible. Surfactant selection is therefore crucial and must be based on physicochemical properties, stability of the interfacial film, mobility of the molecules in the interfacial film, HLB, film formation kinetics, compatibility and interactions between molecules on the surface, CMC, etc. Interfacial rheological properties have yet to be thoroughly explored. Only recently, methods have been introduced that provide sufficient sensitivity to reliably determine viscoelastic interfacial properties. In general, interfacial rheology describes the relationship between the deformation of an interface and the stresses exerted on it.Due to the variety in deformations of the interfacial layer (shear and expansions or compressions), the field of interfacial rheology is divided into the subcategories of shear and dilatational rheology. While shear rheology is primarily linked to the long-term stability of dispersions, dilatational rheology provides information regarding short-term stability. Interfacial rheological characteristics become relevant in systems with large interfacial areas, such as emulsions and foams, and in processes that lead to a large increase in the interfacial area, such as electrospinning of nanofibers.

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Section: Stability Of Gas-liquid and Liquid-liquid Interfaces: Interfmentioning

confidence: 99%

Interfacial rheology: An overview of measuring techniques and its role in dispersions and electrospinning

Pelipenko¹,

Kristl²,

Rošic³

et al. 2012

Acta Pharmaceutica

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“…During the percolation, the hot water flows through the grounded coffee panel, solubilizing and emulsifying proteins and low-molecular weight surfactant, which are responsible for the physical properties of the crema. Particularly some of the oils are emulsified by the pressure provided by the espresso machine and give the creamy sensation of the foam (Piazza et al, 2008). Two distinguish EC foam features are the persistency and foam index.…”

Section: Introductionmentioning

confidence: 99%

A new method for Espresso Coffee brewing: Caffè Firenze

Parenti¹,

Guerrini²,

Masella³

et al. 2013

J Agricult Engineer

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Espresso coffee is the most popular choice for Italian coffee consumers. It has been estimated that every day, in the world, over of 50 million of Espresso cups are taken. As a consequence of this success, a large number of devices to make Espresso have been developed. In this scenario, a new device has been recently developed and patented (Eu. Patent 06 023 798.9; US 2010/0034942 A1). This brew method, named "Caffè Firenze", uses a sealed extraction chamber, where water and gas provides pressure higher than the other extraction methods. Three main parts compose the apparatus: the gas source, the extraction chamber and the heat exchanger. The gas source provides the pressured gas required to raise the pressure of the system. The extraction chamber is made with chrome-brass and accessorized with two heating glow plugs. Many are the factors affecting Espresso quality: it is known that, coffee type, roasting conditions and degree, grinding and storage strongly affect the obtained brew. Also, several studies have been carried out on the effect of the setting parameters on quality, for example water pressure, water temperature, and brew time. Among the characteristics that determine Espresso quality, the main attribute for the visual analysis is, without doubts, the foam, also called "crema". Indeed, height, aspect, and persistency of foam are features much appreciates by consumers. Two distinguish Espresso foam parameters are the persistency and foam index. Equipping a commercial bar machine with the new designed extraction chamber makes feasible the comparison between the traditional way to brew Espresso and the new device. The comparison was made holding the previous mentioned conditions, and differences were evaluated in terms of physical parameters and aromatic profiles.Caffè Firenze shows pronounced differences compared with traditional Espresso in term of foam-related parameters. Also, the new extraction device produces coffees with higher values of body-related parameters, such density and viscosity. The two kinds of Espressos are perceived different at visual analysis and taste by a panel test.

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“…14 Foamability is a desirable property required in some chemical, foods, cosmetic and pharmaceutical processes. [15][16][17][18][19] An ideal foamforming must be non-toxic and able to produce abundant, dense and stable foam, even at low concentration. 20,21 There are several methods to assess foamability and foam stability, 16,22 including the foam decay evaluation and rate of liquid drained from foam.…”

Section: Introductionmentioning

confidence: 99%

Foam-forming properties of Ilex paraguariensis (mate) saponin: foamability and foam lifetime analysis by Weibull equation

et al. 2010

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Recebido em 17/7/09; aceito em 15/3/10; publicado na web em 30/7/10 Saponins are natural soaplike foam-forming compounds widely used in foods, cosmetic and pharmaceutical preparations. In this work foamability and foam lifetime of foams obtained from Ilex paraguariensis unripe fruits were analyzed. Polysorbate 80 and sodium dodecyl sulfate were used as reference surfactants. Aiming a better data understanding a linearized 4-parameters Weibull function was proposed. The mate hydroethanolic extract (ME) and a mate saponin enriched fraction (MSF) afforded foamability and foam lifetime comparable to the synthetic surfactants. The linearization of the Weibull equation allowed the statistical comparison of foam decay curves, improving former mathematical approaches.

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Interfacial rheology study of espresso coffee foam structure and properties

Cited by 70 publications

References 28 publications

Interfacial rheology: An overview of measuring techniques and its role in dispersions and electrospinning

Interfacial rheology: An overview of measuring techniques and its role in dispersions and electrospinning

A new method for Espresso Coffee brewing: Caffè Firenze

Foam-forming properties of Ilex paraguariensis (mate) saponin: foamability and foam lifetime analysis by Weibull equation

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