Caracterização reológica e físico-química de méis de abelha (Apis mellifera L.) do Estado do Piauí.

Abstract

The objective of this work has been to characterize the physical-chemical parameters and the rheological behavior of bee honeys samples (Apis mellifera L.) which have been produced in the state of Piaui. The determination of these parameters, were accomplished in* samples of "Marmeleiro" (Croton sonderianus Mull. Arg.), "Jitirana" (Hyptis suaveolens), "Camaratuba" (Cratylia mollis Mart. Benth), "Silvestre" {Serjania glabrata) and "Angico de Bezerro" [Piptadenia muniliformis) honeys; all these samples collected in the state of Piaui, at Picos, Itainopolis, Vera Mendes and Isaias Coelho cities. It had been followed the recommendation of the Ministry of the Agriculture and provision to make the physical-chemical characterization of these samples. The found medium values were: humidity 19,4%, hydroxymethylfurfural 3,7 mg HMF/kg honey, reducer sugars 77,2%, apparent sucrose 2,47%, ashes 0,10%, free acidity 23 meq/kg honey, insoluble solids in water 0,4%, diastase activity 15,9 DN, °Brix 78,9 and pH 4,2 and all the samples were inside of the demanded patterns by the Ministry of the Agriculture and Provision. The experimental data were collected for the study of the rheological behavior with the aid of a Brookfield viscometer model RVT, with geometry of concentric cylinders, in the temperatures of 2 0 , 25, 30, 3 5 and 40°C. The rheometric experimental data were adjusted by the empiric models of the rheological behavior of Ostwald-of-Waele (Law of Potency) and Herschel-Bulkley, and both represented a good adjustment to the experimental data. According to the obtained results (R2>0,98) we can note that any model in the estimation of rheological behavior of the studied honeys can be used. All the samples presented non-newtonian behavior, with characteristic of pseudoplastics fluid the apparent viscosity of different honeys varied beturen 0,19 and 6 , 5 3 Pa.s for a fix deformation rate ( 3 2 s~1). The temperature effect in the apparent viscosity followed a Arrhenius relation.