PRELIMINARY DATA ON BRAZILIAN MONOFLORAL HONEY FROM THE NORTHEAST REGION USING FT-IR ATR SPECTROSCOPIC, PALYNOLOGICAL, AND COLOR ANALYSIS

Abstract

Fourier transform infrared attenuated total reflectance (FT-IR ATR) spectroscopy was used to determine 14 different measurands in northeast Brazilian honey samples. Nine different honey samples (six monofloral and three polyfloral) from 2009 obtained from the company CEARAPI underwent FT-IR ATR, palynological, color, and sensorial analysis to obtain preliminary results for these types of honey. The results showed that there are five monofloral, three bifloral, and one extrafloral honey, and also that mid-infrared spectrometry can be used as a screening method for the routine analysis of Brazilian honey, with the advantages of being rapid, nondestructive, and accurate. Infrared (IR) Spectroscopy deals with the infrared part of the electromagnetic spectrum. It measures the absorption of different IR frequencies by a sample positioned in the path of an IR beam. Currently, infrared spectroscopy is one of the most common spec- troscopic techniques used in the food industry. With the rapid de- velopment of infrared spectroscopic instrumentation software and hardware, the application of this technique has expanded into many areas of food research. It has become a powerful, fast, and nondes- tructive tool for food quality analysis and control. Fourier Transform (FT) Spectroscopy is an instrumental technique in which spectra are acquired based on measurements of electromagnetic radiation using time domain or space domain and a mathematical method (F T) is applied to convert the raw data to frequency domain. The main application of FT Spectroscopy is the acquisition of absorption spectra.1 IR is based on the absorption of electromagnetic radiation at wavelengths in the range between 800 and 2500 nm. This technique has many advantages such as being rapid and nondestructive, and allows the determination of multiple measurands in a single step.2 Quantitative Infrared Spectroscopy is generally based on calibra- tions by partial least squares (PLS) regression between the spectra and the results obtained by physicochemical reference methods. Building the statistical model is relatively time consuming, and is only profitable if a large number of samples can be analyzed. 2 In this study, a previously published calibration was used,3 which had been successfully used for predicting the physicochemical parameters in the quality control of stingless bee Brazilian honey.4 Infrared Spectroscopy of different monofloral honey samples and subsequent statistical analysis using principal component analysis (PCA) and linear discriminant analysis (LDA) showed that successful classification of the botanical origin of honey is possible. MIR (mid - -infrared) spectroscopy has been successfully used for classification of monofloral European honey. 2,5,6