Dose-Dependent Differentiation of Gamma-Irradiated Hazelnut Samples by Mid-Infrared Spectroscopy Coupled with Chemometrics

Ayca Dogan,Jose S Camara,Feride Severcan,Mete Severcan

doi:10.1155/2020/8859104

Abstract

Gamma irradiation is used as a food preservation method. It is known that high-dose irradiation causes several structural and functional damages. Therefore, the detection of high-dose irradiated food samples is a critical issue in international trade. The objective of this work is to evaluate the potential of Fourier transform infrared (FTIR) spectroscopy for the differentiation of γ-irradiated hazelnuts at higher doses (3 kGy and 10 kGy) from the lower (1.5 kGy) and nonirradiated ones using multivariate statistical analysis, namely, principal component analysis (PCA) and hierarchical cluster analysis (HCA). This study showed that high-dose irradiated hazelnut samples can be clearly differentiated from the low-dose irradiated samples using unsupervised methods based on the spectral differences. Furthermore, dose-dependent discrimination was also achieved. In conclusion, FTIR spectroscopy combined with multivariate statistical analysis has potential for the development of a reliable and fast methodology for separation of high-dose irradiated food samples.

Highlights

Hazelnut (Corylus avellana L.) has importance in human nutrition and health because of its unique fat and nonfat composition, which affects human health positively [1, 2]. e role of hazelnut in reducing the cardiovascular disease, diabetes, and cancer has been reported [3]
To obtain nut tissue powder, all samples were ground and dried in a MAXI dry lyo freeze dryer for overnight. en, the ground samples mixed with potassium bromide (KBr) in a 1/100 ratio. is powder was compressed into a thin KBr disk under a pressure of ∼100 kg/cm2 for 8 minutes for Fourier transform infrared (FTIR) spectroscopic investigation. is process was repeated three times for each control and irradiated samples, and the average spectrum was obtained for each sample using OPUS Software Programme
We focused on FTIR spectroscopy coupled with multivariate analysis, which is used to monitor the differentiation of hazelnut samples in response to gamma irradiation treatment. e power and sensitivity of FTIR spectroscopy together with a multivariate spectral analysis, namely, cluster and principal component analyses, were tested

Summary

Introduction

Hazelnut (Corylus avellana L.) has importance in human nutrition and health because of its unique fat (mainly oleic acid) and nonfat (protein, natural sterols, dietary fiber, tocopherols, and phenolic antioxidants) composition, which affects human health positively [1, 2]. e role of hazelnut in reducing the cardiovascular disease, diabetes, and cancer has been reported [3]. Hazelnut and its processed products are used in food, pharmaceutical, and cosmetic industry [6]. One of the main problems in hazelnut industry is to keep quality maintenance during storage due to insect disinfection and food-borne pathogens [7]. Quality of nuts can be affected during the storage period due to the changes in the physiology and biochemistry of the nut after harvesting [8]. Erefore, clear understanding of the physiological and biochemical changes of plants during the postharvest period will contribute to improve storage conditions and preserve the quality of food samples. To prevent the postharvest loss of hazelnut and other crops, food irradiation is recognized as an effective technology [9]

Methods

Results

Conclusion