Vibrational Spectroscopy Combined with Chemometrics as Tool for Discriminating Organic vs. Conventional Culture Systems for Red Grape Extracts.

Cristiana Radulescu,Cristina Mihaela Nicolescu,Radu Lucian Olteanu,Lavinia Claudia Buruleanu,Georgeta Carmen Holban,Marius Bumbac

doi:10.3390/foods10081856

Abstract

Food plants provide a regulated source of delivery of functional compounds, plant secondary metabolites production being also tissue specific. In grape berries, the phenolic compounds, flavonoids and non-flavonoids, are distributed in the different parts of the fruit. The aim of this study was to investigate the applicability of FTIR and Raman screening spectroscopic techniques combined with multivariate statistical tools to find patterns in red grape berry parts (skin, seeds and pulp) according to grape variety and vineyard type (organic and conventional). Spectral data were acquired and processed using the same pattern for each different berry part (skin, seeds and pulp). Multivariate analysis has allowed a separation between extracts obtained from organic and conventional vineyards for each grape variety for all grape berry parts. The innovative approach presented in this work is low-cost and feasible, being expected to have applications in studies referring to the authenticity and traceability of foods. The findings of this study are useful as well in solving a great challenge that producers are confronting, namely the consumers’ distrust of the organic origin of food products. Further analyses of the chemical composition of red grapes may enhance the capability of the method of using both vibrational spectroscopy and chemometrics for discriminating the hydroalcoholic extracts according to grape varieties.

Highlights

IntroductionThe beneficial health effects of fruits have been attributed to the presence of fibers, minerals, vitamins (i.e., provitamin A, carotenoids, vitamins C and E) and phytochemicals, including phenolic acids, flavonoids, and anthocyanins
The beneficial health effects of fruits have been attributed to the presence of fibers, minerals, vitamins and phytochemicals, including phenolic acids, flavonoids, and anthocyanins
The results showed that differences exist between the spectral profiles of hydroalcoholic extracts from different culture for Merlot, Feteasca Neagra, Pinot Noir and Muscat Hamburg varieties, confirming that the Fourier transform infrared (FTIR) and Raman spectra contain important information for discriminating among samples

Summary

Introduction

The beneficial health effects of fruits have been attributed to the presence of fibers, minerals, vitamins (i.e., provitamin A, carotenoids, vitamins C and E) and phytochemicals, including phenolic acids, flavonoids, and anthocyanins. Food plants provide a regulated source of delivery of functional compounds. Most of the bioactive substances have specific functions within the plant. Plant secondary metabolites production is generally under strict regulatory control and is tissue specific; any attempt to regulate their biosynthesis might result in adverse effects elsewhere in the plant and toxicity [1]. The synthesis of specific metabolites, which can be very plant specific, is controlled through highly branched pathways and carefully regulated. Given the wide diversity in the structure and function of these metabolites in the plant, differences in temporal and spatial distribution of the metabolite can occur, depending on the stage of the development of the plant and between different plant organs and cell types [1,2,3]

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