Effect of water activity on the mechanical properties of selected legumes and nuts

Borges, Antje; Peleg, Micha

doi:10.1002/(sici)1097-0010(199712)75:4<463::aid-jsfa898>3.0.co;2-y

Cited by 27 publications

(24 citation statements)

References 8 publications

(10 reference statements)

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“…In most cases calculated parameters could be used to compare different samples of the same material and to asses its mechanical properties in a consistent manner (Peleg, 1998). The irregular and irreproducible forcedeformation characteristics could be normalized by introduction of dimensionless stress which was used to observe plasticizing and antiplasticizing effect caused by adsorption of water by cereal-based snacks (Barrett, Normand, Peleg, & Ross, 1992;Borges & Peleg, 1997;Marzec, 2002;Nuebel & Peleg, 1993;Rohde, Normand, & Peleg, 1993).…”

Section: Introductionsupporting

confidence: 77%

“…In numerous publications a similar shape of deformation curves for snacks and cereal-based products compressed in bulk was reported (Barrett & Peleg, 1992a, 1992bBorges & Peleg, 1997;Fontanet, Davidou, Dacremont, & Le Meste, 1997;Saklar, Ungan, & Katnas, 1999;Tesch, Normand, & Peleg, 1996;Ulbricht, Normand, & Peleg, 1995). Processes taking place during compression interpret the sigmoid shape of deformation curves of material with sponge-like structure.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Antiplasticization of cereal-based products by water. Part II: Breakfast cereals

Gondek

Lewicki

2006

Journal of Food Engineering

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Section: Introductionsupporting

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Antiplasticization of cereal-based products by water. Part II: Breakfast cereals

Gondek

Lewicki

2006

Journal of Food Engineering

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“…This technique has been also used for the study of mechanical properties of many others beans, see e.g. (Tran et al, 1981, Borges andPeleg, 1997; Al Salah and Galland, 1985). In our previous paper (Nedomova, 2010) results on the coff ee grain compression has been presented.…”

supporting

confidence: 63%

Strength of coffee beans under static and dynamic loading

Nedomová¹,

Trnka²,

Stoklasová³

et al. 2013

Acta Univ. Agric. Silvic. Mendelianae Brun.

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NEDOMOVÁ ŠÁRKA, TRNKA JAN, STOKLASOVÁ PAVLA, BUCHAR JAROSLAV: Strength of coff ee beans under static and dynamic loading. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 3, pp. 743-749 Paper deals with experimental research on the crushing of coff ee beans of diff erent kinds under quasi-static and dynamic compression. The process of the crushing is described in details. It has been shown that there is variability in the crushing strength values. A relation between crushing strength and the coff ee grain shape is also studied. Roasted Arabica coff ee (Coff ea arabica) beans were used for analyses. Arabica coff ees were produced in diff erent countries. All Arabica samples were submitted to a light roast. The detail analysis of the experimental data shows that there is no signifi cant relation between parameters describing the fracture behaviour of the grains and grain geometry. These parameters are also independent on the grain weight. Compression of the coff ee grains leads to their crushing. The fracture force is diff erent for the diff erent kinds of the coff ee. The same is fact valid also for the strain at the fracture and for the energy absorbed during the grain crushing. Dynamic loading leads to the increase in the fracture force of coff ee grains in comparison with the quasi static loading. coff ee beans, compression loading, strength, impact loadingThe knowledge of the strength and toughness of the coff ee beans is necessary in order to evaluate their brittleness. The reaching of a certain degree of brittleness is very important for the grinding to which coff ee beans have to be subjected to before brewing. The uniformity of the product of the grinding process depends on various factors including the brittleness of the roasted coff ee bean and it aff ects the extraction of soluble solids to obtain the coff ee brew (Clo and Voilley, 1983;Clarke and Macrae, 1987). Even though the changes in the textural and mechanical characteristics to which the coff ee bean undergo during roasting play a relevant role in the quality of the roasted beans, these properties have been scarcely studied until now.The textural changes of coff ee beans during their roasting have been studied e.g. by Pitia et al. (2001) using of the static compression of the coff ee beans. The same technique has been used for the study of the infl uence of the moisture content and water activity on the mechanical properties of the coff ee beans (Pitia et al., 2007). This technique has been also used for the study of mechanical properties of many others beans, see e.g. (Tran et al., 1981, Borges andPeleg, 1997; Al Salah and Galland, 1985). In our previous paper (Nedomova, 2010) results on the coff ee grain compression has been presented. These results have been obtained for the quasi static loading.The grinding of the coff ee represents a loading process which is dynamic rather than static. It means the mechanical properties like crushing strength should be evaluated at the dynamic loading. In ...

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“…Os tratamentos 9; 10 e 8 diferenciaram-se significativamente dos tratamentos 3; 5; 4 e 11, evidenciando que os ensaios afetaram distintamente a absorção e a dessorção de água da amêndoa. BORGES & PELEG (1997) afirmaram que a presença de óleo nas nozes parece ser a principal causa da ausência de fragilidade, sendo o fator limitante da absorção ou dessorção de água, tornando-as mais ou menos rígidas. A afirmação é válida para a amêndoa da castanha de caju que, para os tratamentos considerados, tanto na absorção como na dessorção, apresentaram alterações relativamente pequenas no teor de água, comparadas àquelas sofridas pela casca.…”

Section: Determinação Do Teor De áGuaunclassified

Características físicas e mecânicas do endocarpo e da amêndoa da castanha de caju 'CCP 76' antes e após tratamento térmico

Araújo¹,

Ferraz²

2008

Eng. Agríc.

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RESUMO:As características viscoelásticas da casca da castanha de caju in natura dificultam a sua decorticação por compressão. Para facilitar a abertura da casca e a liberação da amêndoa, as castanhas são submetidas à hidratação e tratamento térmico em banho de líquido da casca da castanha (LCC) a 210 °C. Com o objetivo de conhecer o comportamento do produto, para futuros desenvolvimentos de mecanismos decorticadores, procurou-se caracterizar a castanha do clone 'CCP 76' por meio das principais dimensões, massa, volume e ensaios mecânicos do endocarpo e da amêndoa, antes e após o tratamento térmico. Os tratamentos consistiram em várias combinações de tempo de hidratação e tempo de residência em banho de LCC. Aplicou-se a metodologia de superfície de resposta para identificar o melhor tratamento. Construíram-se dispositivos de abertura manual da castanha, cisalhamento do endocarpo e penetração da amêndoa para a realização dos ensaios mecânicos. Observaram-se alterações no comprimento, na largura e na espessura, assim como na massa e no volume, antes e após os tratamentos. Os resultados do ensaio de cisalhamento do endocarpo e da rigidez da amêndoa indicam diferença entre o material in natura e o tratado termicamente. As alterações nas dimensões de massa e de volume apontam para a necessidade de uma classificação após o tratamento térmico, quando essas constituírem parâmetros relevantes no processo de decorticação. A tendência da superfície de resposta mostrou que o ensaio com 79 h de hidratação e 165 s de residência em LCC a 210 °C foi o mais próximo da região de ótimo. PALAVRAS-CHAVE: Anacardium ocidentale, viscoelasticidade, propriedades mecânicas. MECHANICAL CHARACTERISTICS OF ENDOCARP AND KERNEL OF CASHEW NUT 'CCP 76' PRIOR AND POST THERMAL TREATMENTABSTRACT: Viscoelastic characteristics of raw cashew nut shell hinder its decortication by compression. In order to facilitate the shell opening and to liberate the kernel, nuts were subjected to hydration and thermal treatment in cashew nut shell liquid (CSL) at 210 °C. With the objective of developing more appropriate shelling mechanisms the cashew nut 'CCP 76' was characterized by its main dimensions, mass and volume, as well as mechanical behavior of the endocarp and kernel, prior and after thermal treatments. The treatments consisted in submitting the nuts to several combinations of hydration and thermal treatment times. The response surface methodology was applied to identify the best treatment. Specially built devices were used for manual opening of the cashew nut, shear of the endocarp and penetration of the kernel. Changes were observed in the dimensions, length, width, and thickness as well as in mass and volume values prior and after treatments. Results of endocarp shear and kernel stiffness tests pointed out differences between raw and treated nuts. Changes in dimensions, mass, and volume pointed out to performing sizing after thermal treatments if dimensions are relevant in shelling. The response surface methodology indicated that the treatment compris...

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Effect of water activity on the mechanical properties of selected legumes and nuts

Cited by 27 publications

References 8 publications

Antiplasticization of cereal-based products by water. Part II: Breakfast cereals

Antiplasticization of cereal-based products by water. Part II: Breakfast cereals

Strength of coffee beans under static and dynamic loading

Características físicas e mecânicas do endocarpo e da amêndoa da castanha de caju 'CCP 76' antes e após tratamento térmico

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