Application Of ~1H Nuclear Magnetic Resonance For The Identification Of Honey Floral Origin And Adulteration

Honey,as a kind of natural sweeteners,is very popular all over the world.Unfortunately,there is growing occurrence of adulterated and falsely-labelled Chinese monofloral honeys.Several methods have been applied for identifying honey quality.However,there are some limitations about these methods such as unreliability and expertise and so on.In recent years,~1H Nuclear Magnetic Resonance(~1H NMR)technology has been widely used for the identification of adulteration and traceability of many agricultural products,but few researches are reported regarding the use of the technique for honey quality.This study was carried out using NMR spectroscopy with chemometric methods to classify floral origins and syrup adulteration of honey such as rape honey,acacia honey and lychee honey.The methods could be applied to technical support for the healthy development of bee products industry.This paper is mainly divided into three parts:1.Nuclear Magnetic Resonance(NMR)spectra combined with chemometrics methods were employed to identify and classify acacia,rape and lychee honey.According to the study of One-way analysis of variance(ANOVA),it is inferred that there may be significant differences among the contents of proline,?-glucose and turanose.In the pretreatment process,phosphoric acid butter was added to inhibit the water peak of NMR.Based on the optimized range,both partial least squares discriminant analysis(PLS-DA)and orthogonal partial least squares discriminant analysis(OPLS-DA)models were built.The results showed that the identification effect was best by UV scaling chemical analysis interval between 0.10 and 6.00,.The discriminant effect of OPLS-DA model is better than that of PLS-DA model,the discriminant interpretation ability of the OPLS-DA model is 95.8%for samples and 90.5%for unknown samples.Therefore,the integral interval of?0.10-6.00 combined with OPLS-DA model could be used to classify honey according to their floral origins.2.Nuclear Magnetic Resonance(NMR)spectra combined with chemometrics methods were applied to analysis acacia honey mixed with rape honey.A total of 13 concentration gradients mixed honey samples with 5%-90%rape honey were prepared.Based on the optimized integral interval,two models were established including orthogonal partial least squares discriminant analysis model and partial least squares analysis model.The results showed that after UV scaling with?0.10-6.00,acacia honey,rape honey and mixed honey could be identified effectively,and the lowest amount of identifiable adulteration was 10%.3.Nuclear Magnetic Resonance(NMR)spectra combined with chemometrics method were applied to detect the adulterated samples with different proportions of rice syrup,beet syrup and corn syrup.A total of 8 concentration gradients mixed syrup with 5%-70%rape honey were prepared.The results showed that after UV scaling,the OPLS-DA model based on the data of?3.00-6.00 can effectively distinguish the adulterated samples with at least 5%syrup from the pure honey samples.