Roasting

About: Roasting is a research topic. Over the lifetime, 12505 publications have been published within this topic receiving 92988 citations. The topic is also known as: roasting (cooking).

Paleotemperature Analysis of Caribbean Cores P6304-8 and P6304-9 and a Generalized Temperature Curve for the past 425,000 Years

Abstract: Different techniques for preparing organic carbonates for mass spectrometric analysis may give slightly different results depending upon the material used and the grain size to which it is reduced. Two deep-sea cores from the central Caribbean have been analyzed. The samples from one core have been treated with vacuum roasting, and the samples from the other core have not been roasted. The two sets of results are similar and differ 0.5‰ from samples that have been ground to powder and roasted in a stream of helium. When using pelagic Foraminifera, no roasting and vacuum roasting appear to yield isotopic results slightly closer to the true temperature than the results obtained with helium roasting. The two cores analyzed and others previously described are correlated by means of several different criteria. This correlation yields a generalized temperature curve which extends from the present to 425,000 years ago. The high (.997), direct correlation observed between the stratigraphic positions of the isotop...

Effect of roasting on the formation of chlorogenic acid lactones in coffee.

Abstract: Of all plant constituents, coffee has one of the highest concentrations of chlorogenic acids. When roasting coffee, some of these are transformed into chlorogenic acid lactones (CGL). We have studied the formation of CGL during the roasting of coffee beans in Coffea arabica cv. Bourbon; C. arabicacv. Longberry; and C. canephora cv. Robusta. Individual CGL levels were determined by comparison of HPLC peaks with those of synthetic CGL standards. Seven CGL were identified: 3-caffeoylquinic-1,5-lactone (3-CQL), 4- caffeoylquinic-1,5-lactone (4-CQL), 3-coumaroylquinic-1,5-lactone (3-pCoQL), 4-coumaroylquinic-1,5-lactone (4-pCoQL), 3-feruloylquinic-1,5-lactone (3-FQL), 4-feruloylquinic-1,5-lactone (4-FQL), and 3,4-dicaffeoylquinic-1,5-lactone (3,4-diCQL). 3-CQL was the most abundant lactone in C. arabica and C. canephora, reaching peak values of 230 +/- 9 and 254 +/- 4 mg/100 g (dry weight), respectively, at light medium roast ( approximately 14% weight loss). 4-CQL was the second most abundant lactone (116 +/- 3 and 139 +/- 2 mg/100 g, respectively. The maximum amount of CGL represents approximately 30% of the available precursors. The relative levels of 3-CQL and 4-CQL in roasted coffee were reverse to those of their precursors in green coffee. This suggests that roasting causes isomerization of chlorogenic acids prior to the formation of lactones and that the levels of lactones in roasted coffee do not reflect the levels of precursors in green coffee.

Chemical characterization and antioxidant properties of coffee melanoidins.

Abstract: Melanoidins, the brown polymers formed through Maillard reaction during coffee roasting, constitute up to 25% of the coffee beverages' dry matter. In this study chemical characterization of melanoidins obtained from light-, medium-, and dark-roasted coffee beans, manufactured from the same starting material, was performed. Melanoidins were separated by gel filtration chromatography and studied by MALDI-TOF mass spectrometry. Results showed that the amount of melanoidins present in the brews increased as the intensity of the thermal treatment increased, while their molecular weight decreased. The antioxidant activity of melanoidins isolated from the different brews was studied by using different methodologies. Melanoidins antiradical activity determined by ABTS(*)(+) and DMPD(*)(+) assays decreased as the intensity of roasting increased, but the ability to prevent linoleic acid peroxidation was higher in the dark-roasted samples. Data suggest that melanoidins must be carefully considered when the relevance of coffee intake in human health is studied.