Sugar profiles and conductivity of stingless bee honeys from Venezuela

Apidologie, Jan 1996

S. Bogdanov, P. Vit, V. Kilchenmann

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Sugar profiles and conductivity of stingless bee honeys from Venezuela

Sugar profiles and conductivity of stingless bee honeys from Venezuela S Bogdanov 2 P Vit 2 0 Departamento Ciencia de los Alimentos, Facultad de Farmacia, Universidad de Los Andes , Mérida , Venezuela 1 Bee Department, Federal Dairy Research Station , 3097 Liebefeld, Bern , Switzerland 2 V K1ilchenmann Summary — The HPLC sugar profiles and the conductivity of 42 stingless bee honey samples from Venezuela were determined. Three of the honey types were produced by Melipona species (n = 24), while the rest belonged mainly to five Trigona species. The main sugars of the Melipona honeys were fructose and glucose, with an average of 36.7 g/100 g. The Trigona (Frieseomelitta) honeys had a completely different sugar spectrum. There the principal sugar was a disaccharide with the retention time of maltose with an average content of 32.3 g/100 g, while fructose and glucose had smaller concentrations: 24.4 and 18.1 g/100 g respectively. The Melipona honeys contained also small quantities of maltose and only traces of oligosaccharides, while the Trigona honeys had small but measurable amounts of turanose, trehalose and erlose. The conductivity values of the Melipona honeys varied from 0.32 to 0.44 mS/cm and were significantly lower than those of the non-Melipona ones with minimum and maximum values of 1.04 and 1.07 mS/cm. honey / sugar / conductivity / HPLC / Meliponinae / Venezuela - INTRODUCTION The carbohydrates are the major components of honey. The monosaccharides fructose and glucose are the dominant fraction and account for 85-95% of the honeybee honey sugars, the remainder being represented by a number of different di- and trisaccharides ( Doner, 1977 ; Bogdanov and * Correspondence and reprints The sugar composition of stingless bee honeys has been studied occasionally. Nogueira-Neto (1953) , Maurizio (1964) and Phadke (1968) presented fructose, glucose and sucrose values for few samples of Melipona and Trigona honeys. Roubik (1983) measured the sugar concentration of honey in 86 colonies of 27 stingless bee species from Panama, by refractometric Brix units converted into gram equivalents. Klink (1992) analysed enzymatically the glucose, fructose and sucrose content of stingless bee honeys from Costa Rica. Vit et al (1994) compared the reducing sugar- and apparent sucrose content of honeys from 40 colonies of nine stingless bee species from Venezuela, using the Codex alimentarius reducing sugar method. The pollen spectrum of these honeys was also investigated (Vit and Ricciardelli D’Albore, 1994) . The sugar profile and the conductivity are those quality criteria, which are best suitable for differentiating different sorts of honey. In the present study we measured the sugar content by HPLC and the conductivity of 42 stingless bee honey samples from Venezuela and discuss their role in elucidating the entomological origin of stingless bee honeys. However, we cannot correlate our measurements to the floral origin of the honeys, due to the very few monofloral samples (Vit and Ricciardelli D’Albore, 1994) . MATERIALS AND METHODS Honey samples Forty-two honey samples were extracted from sealed honey pots of stingless bee (Apidae, Meliponinae) hives located in different regions of Venezuela during 1987-1988. Due to the restricted number of honey samples from certain species, we can only refer separately to three Melipona: M compressipes compressipes, M favosa favosa, M trinitatis and to one Trigona species: Frieseomelitta aff varia. The other, non-Melipona (mostly Trigona) species, have one or two honey samples each and were grouped together. For further details concerning the honeys and their origin, see Vit et al, 1994. Analysis HPLC analysis was done according to Bogdanov and Baumann (1988) : 10 μL of filtered 20% (g/vol) honey solutions were directly injected on a 25 x 4.6 cm column filled with 3 mm Spherisorb-Amino mounted on a HP 1084 chromatographic system equipped with a Spectraphysics RI-detector 6040 with 80% acetonitrile as eluent. The temperature of the column and the refractometer was 40 °C. The following sugars were used as sugar standards (g/100 mL): 4% fructose and glucose, and 0.5% each of sucrose, turanose, maltose, trehalose, erlose, melezitose and raffinose. Except for erlose (Senn Chemicals, Dielsdorf, Switzerland), all sugars were purchased from Merck or Fluka (Switzerland). The detecting limit of the sugars is 0.1g/100 g honey. Conductivity was measured on 20% (g/g by dry weight) honey solutions at 20 °C (Swiss food manual, 1996) and is expressed in millisiemens (mS) per cm. The statistical significance of the differences between the various parameters of each honey group was determined with Fischer’s least-significant-difference test of a Systat software package. RESULTS The results of our analysis are summarised in table I, typical sugar profiles of the two types of HPLC profiles honeys are shown in figure 1. The Melipona honeys had fructose and (...truncated)


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S. Bogdanov, P. Vit, V. Kilchenmann. Sugar profiles and conductivity of stingless bee honeys from Venezuela, Apidologie, 1996, pp. 445-450, Volume 27, Issue 6, DOI: doi:10.1051/apido:19960602