Prediction of Physicochemical Properties in Honeys with Portable Near-Infrared (microNIR) Spectroscopy Combined with Multivariate Data Processing

Abstract

There is an increase in the consumption of natural foods with healthy benefits such as honey. The physicochemical composition contributes to the particularities of honey that differ depending on the botanical origin. Botanical and geographical declaration protects consumers from possible fraud and ensures the quality of the product. The objective of this study was to develop prediction models using a portable near-Infrared (MicroNIR) Spectroscopy to contribute to authenticate honeys from Northwest Spain. Based on reference physicochemical analyses of honey, prediction equations using principal components analysis and partial least square regression were developed. Statistical descriptors were good for moisture, hydroxymethylfurfural (HMF), color (Pfund, L and b* coordinates of CIELab) and flavonoids (RSQ > 0.75; RPD > 2.0), and acceptable for electrical conductivity (EC), pH and phenols (RSQ > 0.61; RDP > 1.5). Linear discriminant analysis correctly classified the 88.1% of honeys based on physicochemical parameters and botanical origin (heather, chestnut, eucalyptus, blackberry, honeydew, multifloral). Estimation of quality and physicochemical properties of honey with NIR-spectra data and chemometrics proves to be a powerful tool to fulfil quality goals of this bee product. Results supported that the portable spectroscopy devices provided an effective tool for the apicultural sector to rapid in-situ classification and authentication of honey.

The Influence of Chemical Contaminants on the Physicochemical Properties of Unifloral and Multifloral Honey

“…Lightly colored honey is preferred over dark honey. Floral origin and the nectar source can influence honey color [ 154 ]. The age, storage conditions, processing and harvesting of honey in old or new combs found in the hive, and time in the formation of the comb in the beehive cause modification of honey color [ 155 ].…”

Evaluating the Presence and Contents of Phytochemicals in Honey Samples: Phenolic Compounds as Indicators to Identify Their Botanical Origin

“…The methodology used for the study of the botanical characteristics was based on the determination of the pollen contained in the honey by centrifugation. In total, 52% of the honey samples contained between 2000 and 10,000 grains of pollen per gram of honey, according to the classes of Maurizio; 39% of these samples contained between 10,000 and 50,000 grains of pollen per gram of honey [19]. The pollen spectrum of the samples consisted of 82 different pollen types, with 45% of them likely to be labelled as monofloral, while the remaining 55% were considered multi-floral, in which was included 16% whose majority origin was honeydew (HD).…”

“…Several analytical procedures have been reported to determine honey physicochemical properties including colour, viscosity, pH, moisture, free acidity, electrical conductivity, sugars, HMF (hydroxymethylfurfural) content, formol index and insoluble solids [15][16][17][18][19], but due to the high number of existing honey varieties, more specific techniques are needed. The use of chromatography coupled to mass detectors (MS) to obtain a deep chemical characterization of this product is a very valuable option.…”

Towards a Better Understanding of Nutritional and Therapeutic Effects of Honey and Their Applications in Apitherapy

“…Moreover, it is well-known that honey undertakes important composition changes during storage, due to the chemical reactions that occur in the presence of high temperature or long preservation conditions [9]. Among these reactions, 5-HMF and diastase [224] are considered key elements for the indication of honey freshness [88,225,226] or possible adulteration with inverted sugars [9]. Furthermore, the 5-HMF content in honey is established by the Codex Alimentarius Standard Commission (5-HMF in honey at 40 mg/kg and 80 mg/kg for tropical origin honeys).…”

“…Different methods are used for analysing the composition of honey and identifying its authenticity, including physicochemical parameters assay [51], using linear discriminant analysis (LDA) [227] or carbon isotope ratios and trace elements [228] and pollen analysis (melissopalynological analysis) [100,229]. Other modern assets available for honey authentication are the chemometric procedure [224,230], mass spectrometry [231,232], high-performance liquid chromatography (HPLC) [233,234], spectroscopy (UV visible), near-infrared (NIR) [114,225], gas chromatography coupled with mass spectrometry (GC-MS) [235,236] or nuclear magnetic resonance (NMR) [237,238]. However, in the majority of cases, when evaluating the authenticity and traceability of honey samples, combined analytical methods are employed by using various clustering and classification algorithms [22,220].…”