Co-Processed Olive Oils with Thymus mastichina L.-New Product Optimization.

Fátima Peres,Suzana Ferreira-Dias,Luisa L Martins,Marta Roldão,Miguel Mourato

doi:10.3390/life11101048

Abstract

Olive co-processing consists of the addition of ingredients either in the mill or in the malaxator. This technique allows selecting the type of olives, the ingredients with the greatest flavoring and bioactive potential, and the technological extraction conditions. A new product—a gourmet flavored oil—was developed by co-processing olives with Thymus mastichina L. The trials were performed using overripe fruits with low aroma potential (cv. ‘Galega Vulgar’; ripening index 6.4). Experimental conditions were dictated by a central composite rotatable design (CCRD) as a function of thyme (0.4−4.6%, w/w) and water (8.3−19.7%, w/w) contents used in malaxation. A flavored oil was also obtained by adding 2.5% thyme during milling, followed by 14% water addition in the malaxator (central point conditions of CCRD). The chemical characterization of the raw materials, as well as the analysis of the flavored and unflavored oils, were performed (chemical quality criteria, sensory analysis, major fatty acid composition, and phenolic compounds). Considering chemical quality criteria, the flavored oils have the characteristics of “Virgin Olive Oil” (VOO), but they cannot have this classification due to legislation issues. Flavored oils obtained under optimized co-processing conditions (thyme concentrations > 3.5−4.0% and water contents varying from 14 to 18%) presented higher phenolic contents and biologic value than the non-flavored VOO. In flavored oils, thyme flavor was detected with high intensity, while the defect of “wet wood”, perceived in VOO, was not detected. The flavored oil, obtained by T. mastichina addition in the mill, showed higher oxidative stability (19.03 h) than the VOO and the co-processed oil with thyme addition in the malaxator (14.07 h), even after six-month storage in the dark (16.6 vs. 10.3 h).

Highlights

Virgin olive oil is the oil extracted from the fruits of the olive tree (Olea europaea L.)
The low moisture content of the olives highlights the need to perform the optimization of water addition in the malaxation trials, in combination with thyme addition
Ash and protein contents of thyme are higher than the values reported by Barros et al [39]

Summary

Introduction

Virgin olive oil is the oil extracted from the fruits of the olive tree (Olea europaea L.)using exclusively mechanical extraction techniques under conditions that will not affect the original composition of the oil. Many research studies have shown that virgin olive oil has bioactive properties with impacts on health, in preventing cardiovascular diseases, cancer, diabetes, and neurodegenerative diseases [1,2,3,4] These benefits are due to its fatty acid profile, especially to the high content in oleic acid, and to the presence of several bioactive compounds [1,5,6,7]. This evidence led the European Union, in 2006, to approve nutritional and health claims for virgin olive oil (VOO), to be included on the label. Combining these aspects with the consumers’ trend towards products offering health benefits, the great challenge to promote and protect this type of olive orchard is related to the production of high-quality oils (extra virgin olive oil—EVOO)

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