Retention Of Aroma Compounds Research Articles

Coupling crossflow microfiltration and nanofiltration for the concentration of aroma compounds in a raspberry hydroalcoholic extract

AbstractThis work investigated the coupling of microfiltration (MF) and nanofiltration (NF) to concentrate the volatile compounds in a raspberry hydroalcoholic extract. Enzymatic treatment increased the MF permeate flux by 30%–50%. The highest MF permeate flux was above 50 kg·h−1·m−2 at a mass reduction ratio of 5. MF allowed efficient clarification of the extract without significant retention of aroma compounds. Among the NF membranes tested using the MF permeate as feed, one membrane was clearly more effective in concentrating the extract in terms of flux (19 kg·h−1·m−2 at 35 bar), retention of aroma compounds (average retention of 85%), phenolic compounds (61%) and dry matter (90%). Three other membranes were of interest for the fractionation of volatiles in both permeate and retentate but with a lower permeate flux. Finally, one membrane retained few aroma compounds but showed 70% dry matter retention, making it a promising method for aroma purification versus dry matter content in the permeate.Practical ApplicationsIn this study, we investigated the coupling of crossflow MF and NF with a pectinolytic pretreatment, in order to concentrate the aroma compounds from a raw organic raspberry extract. The aim was to avoid aroma degradation and reduce the operating costs, compared to the conventional concentration thermal technologies. Few authors have studied aroma concentration by NF, which presents an interesting area of research for industrial applications. This work provides keys for flavor manufacturers to add value to their products at a low cost and with limited environmental impact, producing concentrated natural aroma extracts for food. Another originality of this work for industrial companies was to show that thanks to the same process, several fractionations could be achieved simply by modifying the operating conditions. Therefore, this work contributed to propose new applicable processing for the production of natural flavors in a context of high consumer and market demand for organic ingredients.

Improvement of rheological and sensory properties of Lactobacillus helveticus fermented milk by prebiotics

The fermentation characteristics and aroma-producing properties of Lactobacilli could influence the flavour quality of fermented milk, an important influencing factor of consumers' preference. In this study, fermented milk was prepared using Lactobacillus helveticus and the dynamic changes in the sensory quality of fermented milk throught fermentation were to assess the dynamic changes in sensory quality of fermented milks throughout the fermentation process, including rheological properties and flavour profiles. Styrene, linalool, octanoic acid, and 1-nonanol were considered as the key flavour components during fermentation. The quality of the fermented milk tends to be stabilized after 24-h, showing the minimal off-flavour at 48-h and optimal fermented aroma at 72-h. Three prebiotics (inulin, Galactooligosaccharides and inulin mixed with Galactooligosaccharides) were added to Lactobacillus spiralis fermented milk separately, and the results showed that inulin mixed with Galactooligosaccharides was the most effective group in improving the organoleptic quality of the fermented milk. Overall, the experimental results provide deeper insights into the release and retention of aroma compounds during fermentation and scientific reference for broadening the application of prebiotics and flavour-producing Lactobacilli in fermented milk processing.

Unraveling the influence of lipids on aroma generation in non-smoked bacon during boiling through untargeted lipidomics analysis

This study explored the key lipid precursors that influence the aroma in the lean portion of bacon by investigating the alterations in volatiles and lipid profiles during boiling of bacon. A total of 19 key aroma compounds were identified, with the highest concentration reached after 20 min of boiling. Lipidomic analysis revealed 1211 distinct lipid molecules, predominantly composed of glycerides and glycerophospholipids. Notably, the triglyceride (TG) (16:0/18:0/18:1) and TG (18:0/18:1/18:1) were assumed to contribute to the retention of aroma compounds. Multivariate statistical analysis identified 569 differentially abundant lipids which serve as biomarkers for distinguishing between various boiling times. Correlation analysis identified 67 lipid molecules that exhibited a high correlation (r < −0.8) with aroma compounds, including 23 TG and 9 phosphatidylethanolamine (PE). Removal of the fat portion from bacon and subsequent prolonged boiling resulted in a notable reduction in the glycerolipid content of the bacon, accompanied by a corresponding decline in the concentration of aroma compounds. Consequently, the application of a suitable processing method can result in an optimal aroma of bacon prior to consumption, and TG and PE play vital roles in the formation of aroma.

Comprehensive analysis of key aroma compounds enhanced by Tamarix ramosissima Ledeb in mutton roasted by air-frying roast technology by means of SAFE-GC-O-MS and lipidomics

Little information is known about the increased aroma compounds and possible mechanism in Tamarix ramosissima Ledeb roasted mutton (TRM). A comprehensive analysis of aroma compounds and lipids were firstly performed by lipidomics and sensomics approach. The results indicated that 9 out of 53 aroma compounds were considered as key odorants, including 5-methyl-2,3-diethylpyrazine. The roasted mutton contained highest levels of phosphatidylcholine (PC, 13.95%), triglyceride (TG, 13.50%), and phosphatidylethanolamine (PE, 12.25%). TG 18:0_18:0_18:1 and nine odorants were the potential biomarkers for discriminating differential samples due to variable importance in projection (VIP) > 1 and p < 0.05. PCs and TGs, including PC 21:0_13:1 and TG 16:0_18:1_18:1, might be predominantly responsible for the formation and retention of aroma compounds, respectively. This will clarify the enhanced effect of Tamarix ramosissima Ledeb on the presence of aroma compounds via lipid pathways in roasted mutton.

Potential use of Thai mango (Mangifera indica Linn. cultivar Chok-Anan) seed porous starch for retention of aroma compounds from coffee extract

This study aimed to extract and modify the properties of the starch from Thai mango seeds (cultivar Chok-Anan). The porous starch samples were obtained using enzymatic treatment and its potential to retain aroma compounds from coffee extract was evaluated. The physicochemical properties, structure characteristics, porosity characteristics and adsorption quantity of starches were also determined. The retention of coffee aroma compounds was investigated through combining starch or porous starch with odorants, and storing the mixtures at room temperature for 7 and 14 days, respectively. The chemical properties of aroma compounds as well as starch surface properties were observed to affect the retention of aroma compounds upon storage. Additionally, 2-furanmethanol, d-limonene and maltol were selected to be the primary target compounds to assess the retention of odorants. This study observed a noticeable decrease in d-limonene content throughout the storage period. On the contrary, after 14 days of storage, the porous starch exhibited high retention of hydroxy compounds including 2-furanmethanol and maltol. However, after prolonged storage their ability to retain 2-furanmethanol and maltol slightly decreased. Therefore, the porous starch derived from mango seeds exhibited the potential to retain coffee aroma compounds and could be a desirable green adsorbent for food and cosmetic industries.

Analysis of aroma components changes in Gannan navel orange at different growth stages by HS-SPME-GC–MS, OAV, and multivariate analysis

The ripe Gannan navel oranges have an appealing aroma, but few studies have reported the changes of these aromatic substances during the growth of navel oranges. In this study, changes of aroma components in Gannan navel orange from 119 to 245 days after flowering were systematically studied using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC–MS) coupled with multivariate analysis, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). A total of 43 and 54 aroma components were identified in pulp and peel of navel orange, respectively. The odor active value (OAV) results indicated that 14 substances were the key aroma components during the growth of navel orange. Among them, the contribution of linalool, β-myrcene and limonene were the highest. The multivariate statistical analysis further confirmed that 14 and 18 compounds could be used as key markers to distinguish the pulp and peel at different growth stages, respectively. Results from this study contributed to a better understanding of the dynamic variation and retention of aroma compounds during navel orange growth, and have great potential for industrial application.

Effects of degree of milling on nutritional quality, functional characteristics and volatile compounds of brown rice tea.

This study investigated the effects of rice preparation using different degrees of milling (DOM) from 0% to 13% on the nutritional composition, functional properties, major volatile compounds and safety of brown rice tea (BRT). We found that 2% DOM reduced 52.33% of acrylamide and 31.88% of fluorescent AGEs. When DOM was increased from 0% to 13%, the total phenolic content (TPC) of brown rice tea decreased by 48.12%, and the total flavonoid content (TFC) and condensed tannin content (CTC) also decreased significantly, with the smallest decrease at 2% DOM. In addition, the inhibitory activities of α-amylase, α-glucosidase and pancreatic lipase as well as the antioxidant activity also decreased gradually. Analysis by electronic nose and gas chromatography-mass spectrometry (GC-MS) showed that alkanes, furans, aldehydes, pyrazines and alcohols were the major volatiles in BRT, with 2% DOM having the greatest retention of aroma compounds. An orthogonal partial least squares discriminant analysis (OPLS-DA) and VIP score (VIP > 1 and p < 0.05) analysis were used to screen 25 flavor substances that contributed to the differences in BRT aroma of different DOMs. These results suggest that 2% milled BRT can improve safety and palatability while maximizing the retention of flavor compounds and nutrients. The findings of this study contribute to an enhanced understanding of the dynamics of changes and preservation of aroma compounds and nutrients present during the processing of BRT.

Understanding the role of lipids in aroma formation of circulating non-fried roasted chicken using UHPLC-HRMS-based lipidomics and heat transfer analysis

The role of lipids in aroma formation of circulating non-fried roasted (CNR) chicken with different roasting times was studied using ultra-high performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS)-based lipidomics and heat transfer analysis. Thirteen odorants were confirmed as important aroma compounds of CNR chicken, including dimethyl trisulfide, 3,5-dimethyl-2-ethylpyrazine, nonanal, and 1-octen-3-ol. A comprehensive lipidomics analysis identified 1254 lipids in roasted chickens, classified into 23 distinct lipid categories that included 281 phosphatidylcholines (PC), 223 phosphatidylethanolamines (PE), and 202 triglycerides (TG). Using OPLS-DA analysis, the lipid PG (18:1_18:1) showed promise as a potential biomarker for distinguishing between chickens subjected to CNR treatments with varying roasting times. The lipids PC, PE, and their derivatives are likely to play a crucial role in the formation of aroma compounds. In addition, TGs that contributed to the retention of key odorants in roasted chicken included TG (16:0_16:0_18:1), TG (16:0_16:0_18:0), and TG (16:0_18:1_18:1). Findings further showed that lower water activity and specific heat capacity promoted the formation and retention of aroma compounds during the CNR process. This study contributed to a better understanding of the formation of aroma compounds through lipid oxidation in roasted chicken.

Exploring the formation and retention of aroma compounds in ready-to-eat roasted pork from four thermal methods: A lipidomics and heat transfer analysis

For the first time, the formation and retention effects of key aroma compounds in ready-to-eat pork roasted using circulating non-fried roast (CNR), microwave heat (MWH), superheated steam (SHS) and traditional burning charcoal (BCC) were comprehensively analyzed. The results showed that 20 out of 50 odorants were key aroma compounds. The 2,3-dimethylpyrazine, trimethylpyrazine, and LPC 18:2-SN1 were potential biomarkers that distinguished roasted pork. Phospholipids, especially phosphatidylcholine (PC), phosphatidylserine (PS), and phosphatidylethanolamine (PE), played a crucial role on the generation of key aroma compounds in roasted pork. Moreover, triglyceride (TG) that included TG (16:0_18:1_18:1), TG (16:0_18:0_18:0), and TG (16:0_18:0_18:1) were responsible for the retention of key odorants. This study further found that appropriate heat transfer conditions (thermal conductivity, specific heat capacity), and water activity contributed to the formation and retention of key odorants in roasted pork. The CNR method could be a promising alternative to the traditional BCC method in roasted pork.

Comprehensive binding analysis of glycated myosin with furan derivatives via glucose by means of multi-spectroscopy techniques and molecular docking simulation

Myosin is an ideal binding receptor for aroma compounds and its functional properties are easily affected by glucose. The study comprehensively clarified the effects of glucose glycation-induced structural modifications of myosin on its binding ability with furan derivatives, including 2-methylfuran, 2-furfural, and 2-furfurylthiol. The results demonstrated that the binding levels of furan derivatives were obviously affected by the glycation levels of myosin due to the changes of myosin structure and surface. The increased glycation levels caused the unfolding of myosin structure and accelerated the aggregation, as were exhibited by the data of zeta potential, particle size, microstructure, and secondary structure. The glycated myosin with wrinkled surfaces favored the significant increase of hydrophobic interactions (31.59–69.50 μg), the more exposure of amino acid residues (3459–6048), the formation of free sulfhydryl groups (16.37–20.58 mmol/104g) and hydrogen bonds. These key (non)covalent linkages accounted for the generation of glycated myosin-odorants complex, including 2-furfurylthiol (29.17–47.87 %), thus enhancing the resultant binding ability as evidenced by the free furan derivatives concentrations, fluorescence quenching and molecular docking simulation analysis. The glycated myosin for 8 h bound highest concentrations of furan derivatives. The results will provide comprehensive data on the retention of aroma compounds in meat products.

Insight into the dynamic variation and retention of major aroma volatile compounds during the milling of Suxiang japonica rice

The work compared the aroma profiles of various rice cultivars, and investigated the impacts of milling process on the major volatile compounds and sensory profiles of Su100 rice. Results suggested that a total of 66 volatiles were identified in four rice cultivars, whereas 2-Acetyl-1-pyrroline (2-AP) was only detected in Su100 rice. With increasing the DOM, the contents of most volatile compounds and sensory attributes decreased. Electronic nose and gas chromatography-mass spectrometry (GC–MS) analysis revealed that esters, aldehydes, benzene derivatives and alcohols were dominant volatiles. 6% DOM rice had the greatest number of volatile compounds and best aroma properties. Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) model successfully distinguished the five rice samples varying in the DOM due to their aroma profiles. Moreover, 6 aroma-active compounds were identified by gas chromatography–olfactometry (GC-O) and odor activity values (OAVs). Outcomes from this research contributed to a better understanding of the dynamic variation and retention of aroma compounds in rice processing.

Volatile Composition and Sensory Properties as Quality Attributes of Fresh and Dried Hemp Flowers (Cannabis sativa L.).

Flowers of hemp (Cannabis sativa L.) are widely used in cosmetics, food, and in the pharmaceutical industry. The drying process plays a key role in retention of aroma and also in the quality of products. Seven variants of hemp flower drying, including convection drying (CD), vacuum–microwave drying (VMD), and combined drying consisting of convective pre-drying followed by vacuum–microwave finishing drying (CPD-VMFD) were checked in this study. For each process, we applied the two-term model. Dried material was submitted to color and chromatographical assessments. Analyses of obtained essential oil showed the presence of 93 volatile compounds, predominantly β-myrcene, limonene, and β-(E)-caryophyllene, as well as α-humulene. Application of 240 W during VMD and 50 °C during CD gave the highest retention of aroma compounds, amounting to 85 and 76%, respectively, but with huge color changes. Additionally, sensory analysis proved that drying with a microwave power of 240 W provides a product most similar to fresh material.

Aroma-retention capacities of functional whey protein aggregates: Study of a strawberry aroma in solutions and in fat-free yogurts

The aroma-retention capacity of functional whey protein aggregates (WPA) was compared to that of native whey protein isolate (WPI) in aqueous solutions and in fat-free yogurts. The retention of aroma compounds, constituting a model strawberry aroma, was evaluated by calculating gas-matrix partition coefficients using headspace gas chromatography (HS-GC).The retention capacity of WPA differed from the one of WPI for three out of seven aroma compounds detected in HS-GC. Incorporating WPA in fat-free yogurts tended to decrease the release of hydrophobic aroma compounds such as 2-nonanone or methyl-cinnamate. The magnitude of the differences between the partition coefficients of yogurts enriched in WPI or WPA was lower than in aqueous solutions, which is likely to be due to the higher complexity of the food matrix and potential interactions with other ingredients. Overall, the different aroma-retention capacities of native WPI and functional WPA are likely to lead to unbalanced aroma, especially in fat-free dairy products.

Active Food Packaging Based on Biopolymers and Aroma Compounds: How to Design and Control the Release.

Aroma compounds are known to be efficient active agents for a broad range of applications (antimicrobial, anti-oxidant, insect repellent…) that are highly sought when aiming at extending shelf life of food or biological products. However, they are intrinsically odorant and volatile at ambient temperature, which restricts the processing routes used to introduce them in a polymeric matrix and can affect their mode of action and limit efficiency. Indeed, due to their high sensitivity toward temperature they can be lost or transformed during processing. Acting after being released in the headspace, their concentration has to be controlled to avoid any odorant contamination of the targeted products. Hence, the ability for an aroma compound to be retained in a polymeric matrix, and then released when submitted to a triggering effect, are the two main requirements that should be satisfied. The volatile nature of the aroma compound offer the possibility when introduce in the packaging to act by direct or indirect contact with the product and thus to be used in different ways; as a coating layer directly applied on the product surface, as a self-supported film or as coated paper when associated with a paper sheet, as well as an object that could be inserted in the package. As biopolymers such as proteins and polysaccharides are able to retain aroma compounds but also to favor their release by modification of their structure when the relative humidity (RH) and temperature change, they are relevant carriers of these specific aroma compounds. Examples of how active packaging systems with limonene, eugenol and carvacrol as active agents were designed and elaborated. These examples will be presented with a special focus on the processing conditions and the way to improve their aroma compound retention and the release control (biopolymer nature, cyclodextrin clay addition…). Avrami's equation has been used to model the transfer of aroma compound and to advantageously compare it taking into account the mechanism in relation to the biopolymer structural changes.

Insights in aroma compound retention by mucosa during consumption through mathematical modelling

A multidisciplinary approach combining physiology and physical chemistry and associating experimental measurements with in silico modelling was applied to explain the release of aroma compounds during food consumption. Experimental release kinetics obtained by inhaling gaseous samples through controlled protocols highlighted different release behaviours, depending on aroma compound properties. The associated mathematical model described mass transfer mechanisms between the different compartments of the naso-oro-pharyngeal cavities and included both physicochemical and physiological parameters. One of the main developments was notably to consider the possible retention of aroma compounds by wetted mucosa. Model sensitivity analysis confirmed the key role of interaction between aroma compounds and mucosa (air/mucosa partition coefficient) and of individual breath parameters (current breath volume and respiratory frequency) on the persistence of aroma compound in exhaled air. These achievements show that the association of an experimental approach and mechanistic modelling constitutes a powerful tool to improve the understanding of aroma release and persistence.

Combination of transglutaminase and sourdough on gluten-free flours to improve dough structure.

The aim of this work was to evaluate the effects of microbial transglutaminase (mTG) and sourdough on gluten-free (GF) flours. Besides deamidation and incorporation of amines, mTG catalyses protein cross-links, modifying dough structure. Sourdough from lactic acid bacteria (LAB) and yeast modifies dough protein composition, determining proteolysis, which induce the formation of aroma precursor metabolites. The chemical-physical interactions of volatile molecules with various constituents of the matrix affect the retention of aroma compounds. Here, the effect on volatile molecule profiles and on protein networks formation after mTG treatment in sourdoughs obtained with four GF flours belonging to cereals, pseudo-cereals and legumes (rice, corn, amaranth and lentil) was investigated. Sourdough was prepared with a two-step fermentation using Lactobacillus sanfrancisciensis (LSCE1) and Candida milleri (PFL44), then mTG was added after 21h of fermentation at increasing levels. The results showed that mTG had the capacity to modify GF flour proteins and improve protein networks formation, involving mainly the prolamin protein fraction. This is particularly relevant for the production of GF backed goods generally lacking of technological, structural and sensorial features compared with products obtained with wheat flour sourdough fermentation. Interestingly, mTG treatment of sourdough affected also the volatile composition and indeed possibly the final organoleptic properties of the products.

An approach to adapt aroma in fat-free yoghurt systems: Modelling and transfer to pilot scale

Aroma retention and flavour perception of dairy products largely depend on the fat content of their respective varieties. When the milk fat content of model milk solutions was increased from 2% to 12%, a linear increase in the matrix-air partition coefficient KMG, as determined by the phase ratio variation (PRV) method, was observed for six aroma compounds in the log P range of +1.8 to +4.5, namely ethyl butanoate, ethyl-2-methylbutanoate, (Z)-3-hexenyl acetate, ethyl hexanoate and limonene. (Z)-3-hexenol, the least hydrophobic compound (log P = +1.6), was slightly less retarded at increased fat content. With the exception of limonene, it was observed that the higher the log P, i.e., the hydrophobicity of the aroma compound, the more pronounced was the linear increase of KMG and hence retention. The successful scale-up from basic laboratory research into pilot plant for the aroma compound retention in fat-free yoghurt is presented.

Effect of konjac glucomannan addition on aroma release in gels containing potato starch

The present study aimed to measure the retention of aroma compounds (ethyl acetate, ethyl hexanoate and carvacrol) in dispersions based on konjac glucomannan and/or potato starch, and to highlight the influence of konjac glucomannan on the mechanisms involved in aroma retention. Publications on the effect of konjac glucomannan on aroma release are scarce. Konjac glucomannan is a polysaccharide used as a food additive for its viscous and emulsifying properties. Retention of aroma compounds in dispersions was calculated from partition coefficients which were measured using the phase ratio variation method. This method, consisting of analyses of the headspace at equilibrium, enables the determination of the partition coefficient of volatile compounds in a gas/liquid system without external or internal calibration. The three aroma compounds chosen for this study behave differently toward amylose. Prior to the release study, the complexing behavior of carvacrol with starch, hitherto unknown, was investigated by X-ray diffraction: V6III amylose complexes were formed with carvacrol. Our results showed no specific interaction between ethyl hexanoate and potato starch or konjac glucomannan. Ethyl acetate retention seemed to be due to trapping in the complex network of polysaccharides and to the density of this network. Retention of carvacrol was influenced by the nature of polysaccharides present in the dispersion, and was mainly governed by specific interaction with starch. Additionally, the addition of konjac glucomannan to potato starch dispersions decreased the retention of volatile compounds complexing starch, but had little effect on the retention of the other aroma compounds.

Fining white wine with plant proteins: effects of fining on proanthocyanidins and aroma components

Plant-derived insoluble proteins (wheat gluten, and isolates from pea, lentil, and soybean) were used as fining agents in model white wine (made from Catalanesca grapes) after cold stabilization. Plant proteins were effective in giving a fast and remarkable decrease in turbidity. GC/MS and HPLC/MS approaches indicated that individual proteins had a different impact on the levels of compounds relevant to wine stability. Protein stability of wine was not affected by fining with plant proteins. Lentil proteins and gluten gave the best removal of monomeric and dimeric flavonol. Both caused a decrease in the total content of fermentative aroma compounds, such as ethyl esters, acetate esters, and alcohols. Lentil proteins had the highest impact on the aroma components, giving a marked decrease in aroma components. Gluten may thus be regarded as giving the best balance between fining efficacy and retention of aroma compounds. Also, gluten in the treated wines remained well below the suggested threshold for gluten-free foods. This study provides a methodological frame for thorough characterization of the impact of specific interventions on key wine components.

Retention of aroma compounds by corn, sorghum and amaranth starches

The presented study addressed assays of odorant retention from an essential oil mixture by native corn, sorghum and amaranth starches using capillary gas chromatography (GC) and differential scanning calorimetry (DSC). The essential oil mixture consisted of 30 main compounds, including monoterpene and sesquiterpene hydrocarbons, alcohols, ketone, phenols and ester. The native starches were characterized for their chemical composition (amylose, protein, and surface lipids content), surface properties (surface area, pore diameter), and microstructure (SEM). The starches were mixed with odorants, stirred intensively, and stored at room temperature in the dark for 2days (reference sample), 3 and 7months. The chemical properties of odorants, their composition in the mixture as well as starch surface properties were observed to affect the retention of aroma compounds upon storage. Irrespective of starch botanical origin, a significant loss was noticed in monoterpene hydrocarbons throughout the storage period. Alcohols, ketone, phenols and sesquiterpene hydrocarbons were highly retained on amaranth and sorghum starches upon 3months of storage. However, after prolonged storage their retention diminished, especially in the case of amaranth starch. The DSC results obtained for stored corn and sorghum starches with odorants demonstrated an extra endothermic contribution, which indicated that the aroma compounds were highly retained by the gelatinized starch matrixes. Furthermore, the odorants showed ability to interact with the solubilized amylose.