Shelf-Life Evolution of the Fatty Acid Fingerprint in High-Quality Hazelnuts (Corylus avellana L.) Harvested in Different Geographical Regions.

Marta Cialiè Rosso,Giorgia Purcaro,Steven Mascrez,Federico Stilo,Chiara Cordero,Carlo Bicchi

doi:10.3390/foods10030685

Marta Cialiè Rosso, Giorgia Purcaro + Show 4 more

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https://doi.org/10.3390/foods10030685

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Abstract

Hazelnuts are characterized by a relatively high abundance of oleic acid and poly-unsaturated fatty acids, which give this fruit a high nutritional value. As a counterbalance, such a lipid profile is more susceptible to autoxidation and/or degradation reactions under enzymatic catalysis. Lipid oxidation occurs on fatty acids (FAs), both esterified on triacylglycerols and in free form (after lipolysis), but with favorable kinetics on the latter. In this study, the quali-quantitative changes in FA profiles (both free and esterified) were monitored during the shelf life (time 0, 6, and 12 months) as a function of different drying and storage conditions and different cultivars and geographical areas. A derivatization/extraction procedure was performed to quantify the profile of free and esterified fatty acids accurately. The overall profile of the free and esterified fatty acids concurred to create a biological signature characteristic of the cultivar and of the harvest region. The free and esterified forms’ characterization enabled the efficient monitoring of the effects of both the hydrolytic activity (increment in overall free fatty acids) and the oxidative process (decrease in unsaturated free fatty acids versus esterified fatty acids) over the 12 months of storage.

Highlights

Hazelnuts (Corylus avellana L.) are characterized by high fat content, with triacylglycerols as the main components [1]
Hazelnut lipids are dominated by TAGs combining the six more abundant fatty acids, namely oleic (C18:1 n-9), linoleic (C 18:2 n-6), palmitic (C 16:0), stearic (C 18:0), linolenic (C 18:2 n-3), and arachidic (C 20:0) acids, in different proportions
Hazelnut kernel is rich in monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) and low in saturated fatty acids (SFAs), considering that palmitic and stearic acids represent around 5% and 2% of total fatty acids, respectively [26]

Summary

Introduction

Hazelnuts (Corylus avellana L.) are characterized by high fat content, with triacylglycerols as the main components [1]. The relatively high abundance of monoand unsaturated fatty acids gives this fruit a high nutritional value, as well as a great susceptibility to autoxidation and/or degradation reactions under enzymatic catalysis. Many studies have been carried out to characterize the lipid fraction of hazelnut and to evaluate its stability during the shelf life [4,5,6]. State-of-the-art literature unequivocally indicates the geographical origin and environmental conditions as the most influencing variables on the lipid composition [7,8] in terms of acidic profile. Storage, water activity (aw), and temperature [4,6] have a clear and decisive impact on its chemical stability [9]

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