Enzymatic Process Enhances the Flavour Profile and Increases the Proportion of Esters in Citrus Essential Oils

Abstract

Citrus essential oils (CEOs) are important flavors in the food and confectionary industries. A lipase process was proposed for enhancing the flavor profiles and increasing the proportions of esters in CEOs. The effects of the enzymatic process were explored by detecting the constituents of the CEOs of American sweet orange oil (ASO) and Brazil mandarin oil (BMO) through GC/MS and sensory evaluation by a trained panel, and positive effects were confirmed by both methods. A further eleven kinds of CEOs were treated via the lipase process and increments of 10 - 1170% were achieved in the proportions of esters, which were mostly ethyl esters. Enhancement in fruity odor, especially the top note, was demonstrated by all CEOs after enzymatic processing. All CEOs were tested for antimicrobial activities, and only ASO displayed fairly ideal antimicrobial activities. Meanwhile, modified ASO showed a certain increase in antimicrobial activities. This methodology might be considered a sustainable route for acquiring 'natural' essential oils with enhanced flavor profiles and simultaneously enhancing the comprehensive utilization of citrus fruits.

Simultaneous geraniol and citronellol transesterification using Pseudomonas fluorescens lipase for the production of fragrance, flavour and pharmaceutical esters: a kinetic study

“…It was observed that esterification has the inherent disadvantage of deactivating the enzyme owing to the low pH caused by the acetic acid reagent. Modification of the aromatic profiles of palmarosa oil [17] and citrus oil [18] to broaden their applications has also been reported. More recently, lipase-catalysed transesterification of various essential oils, such as citronella oil, was studied by Amaral et al [19] who showed 90 to 100% conversion of primary terpene alcohols in various essential oils for a reaction time of 24 hours.…”

Lipase-catalysed changes in essential oils revealed by comprehensive two-dimensional gas chromatography

“…Following a recent screening and optimisation study [7], the present work focuses on the application of the immobilised Candida antarctica lipase A (CALA)-identified as the best-performing commercial biocatalyst in previous stages of this study-to the biotransformation of terpenoid and phenyl alcohols in essential oil samples. Unlike other similar studies targeting only one or a few samples or standards [5,[8][9][10][11][12], the performance of the aforementioned biocatalyst towards an extensive number of alcohol substrates in 35 natural samples of different complexities is investigated here, in order to better understand the selectivity and inhibition effects (if any) involved in such processes. Comprehensive two-dimensional gas chromatography with mass spectrometry detection (GC×GC-MS) was used for its superior resolution and improved compound identification capacity, enabling the qualitative assessment of reaction changes in samples of different complexities.…”

Air Diffusion of Aroma-Active Components from Crude Citrus Essential Oils and Their Extract Phases Obtained by Solvent Extraction

“…Citrus essential oils (CEOs) are important raw materials present in the formulation of perfumes, foods, beverages, soft drinks, cosmetics, pharmaceuticals, and so on. − The volatile fraction of CEOs is mainly composed of terpenes (∼0.95 mass fraction), which have been reported as unstable components, easily degraded when exposed to the air, light, or heat, generating compounds with unpleasant odor that will compromise the final aroma and commercial value of the CEOs. , CEOs are also composed of oxygenated compounds, which, although in lower amounts, are mainly responsible for the typical CEOs’ aroma, accounting for their quality and price establishment . Solvent extraction is a technique widely applied to separate the oxygenated fraction from the terpenes present in this kind of natural matrix ,− that allows one to maintain the original CEO aroma , and improve its stability .…”