Natural Aroma Compounds Research Articles

Use of natural aroma compounds to improve shelf-life and safety of minimally processed fruits

Minimally processed fruits are an important area of potential growth in rapidly expanding fresh cut produce. However, the degree of safety obtained with the currently applied preservation methods seems to be not sufficient. The interest in the possible use of natural compounds to prevent microbial growth has notably increased in response to the consumer pressure to reduce or eliminate chemically synthesized additives in foods. The aim of this work is to give an overview on the application of natural compounds, such as hexanal, 2-(E)-hexenal, hexyl acetate and citrus essential oils, to improve the shelf-life and the safety of minimally processed fruits as well as their mechanisms of action.

Scale-up of pervaporation for the recovery of natural aroma compounds in the food industry Part 2: optimisation and integration

In this study the integration and optimisation of hydrophobic pervaporation for the recovery of natural aroma compounds in the food industry has been studied. The simulation developed in the first part of this study was applied to the design and scale-up of pervaporation units for the recovery of natural apple juice aroma. Both semi-batch and continuous process configurations were considered and the process conditions were optimised taking the cost of the process into account. For the semi-batch process, the cost per kg concentrated aroma was between 31.30 and 33.60 ▪, depending on the membrane type. When returning the recovered aroma to the apple juice after heat treatment, the cost of aroma recovery per kg concentrate was between 0.31 and 0.34 ▪. In the case of the continuous process, the cost for the apple juice aroma recovery was between 2.19 and 5.38 ▪, while the cost of aroma recovery per kg apple juice was between 0.03 and 0.05 ▪. Upon analysing the optimised processes with a sensitivity analysis of the key cost factors associated with pervaporation, membrane life-time and membrane cost, it was revealed that the membrane life-time is more important than the membrane cost and that the continuous process is more sensitive to changes in membrane life-time and membrane cost. Overall, this study revealed that pervaporation has the potential to become an alternative to conventional processes in recovering and concentrating aroma compounds in the food industry.

Scale-up of pervaporation for the recovery of natural aroma compounds in the food industry. Part 1: simulation and performance

The possibility of using pervaporation for the recovery of natural aroma compounds in the food industry has been widely recognised. The aim of this study was to build a bridge between experimental studies of multi-component systems and potential applications of pervaporation in the food industry. Therefore, a novel process simulation of pervaporation has been developed for multi-component mixtures. By applying this simulation to 10 aroma compounds of relevance in the food industry, the influence of process parameters such as permeate pressure, feed temperature, degree of aroma folding and membrane area, on the performance of pervaporation has been investigated. Based on the results of the simulations, it has been demonstrated that process simulation can play an important role in integrating and optimising pervaporation in the food industry.

A novel approach for the production of natural aroma compounds using agro-industrial residue

Experiments were carried out to study the production of aroma compounds from coffee husk by a fungal culture of C. fimbriata in solid state fermentation. Hot water treated coffee husk seemed to be useful substrate for aroma production in comparison to whole coffee husk or its water extract. Raw data were integrated in order to calculate the total volatiles (TV) accumulated during the fermentation using the Gompertz model. Glucose addition between 20–35% increased significantly the yields of aroma compounds. Supplementation of leucine further improved the TV production significantly (about 58%), specially the esters. When soybean oil was added, TV production was similar to the control, showing that the fungus was not able to use soybean oil for its primary metabolism, nor it acted as precursor for the synthesis of methyl ketones as reported for other fungi. Addition of saline solution drastically decreased the volatile production. Under optimized conditions, a total of 13 compounds were produced which included alcohols (2), aldehyde (1), ketones (2) and esters (8). Ethyl acetate was the prominent compound, followed by ethanol.

Isolation of a Bacillus sp. capable of transforming isoeugenol to vanillin

Natural aroma compounds are of major interest to the flavor and fragrance industry. Due to the limited sources for natural aromas, there is a growing interest in developing alternative sources for natural aroma compounds, and in particular aromatic aldehydes. In several microbial species aromatic aldehydes are detected as intermediates in the degradation pathway of phenylpropanoids. Thus, bioconversion of phenylpropanoids is one possible route for the production of these aroma compounds. The present work describes the isolation of microbial strains, capable of producing vanillin from isoeugenol. Bacterial strains isolated from soil, were screened for their ability to transform isoeugenol to vanillin. One of these strains, strain B2, was found to produce high amounts of vanillin when grown in the presence of isoeugenol, and was also capable of growing on isoeugenol as the sole carbon source. Based on its fatty acids profile, strain B2 was identified as a Bacillus subtilis sp. The bioconversion capabilities of strain B2 were tested in growing cultures and cell free extracts. In the presence of isoeugenol, a growing cultures of B. subtilis B2 produced 0.61 g l −1 vanillin (molar yield of 12.4%), whereas cell free extracts resulted in 0.9 g l −1 vanillin (molar yield of 14%).

Biotechnological production of flavours and fragrances.

The biotechnological generation of natural aroma compounds is rapidly expanding. Aroma chemicals, such as vanillin, benzaldehyde (bitter almond, cherry) and 4-(R)-decanolide (fruity-fatty) are marketed on a scale of several thousand tons per year. Their possible production by single-step biotransformations, bioconversions and de novo synthesis using microorganisms, plant cells or isolated enzymes is shown. The perspectives of bioprocesses for the oxifunctionalisation of lower terpenes by genetically modified organisms and economic aspects are discussed.