Aroma Enrichment Research Articles

The m6A reader SlYTH2 negatively regulates tomato fruit aroma by impeding the translation process

N6-methyladenosine (m6A) is a fundamentally important RNA modification for gene regulation, whose function is achieved through m6A readers. However, whether and how m6A readers play regulatory roles during fruit ripening and quality formation remains unclear. Here, we characterized SlYTH2 as a tomato m6A reader protein and profiled the binding sites of SlYTH2 at the transcriptome-wide level. SlYTH2 undergoes liquid-liquid phase separation and promotes RNA-protein condensate formation. The target mRNAs of SlYTH2, namely m6A-modified SlHPL and SlCCD1B associated with volatile synthesis, are enriched in SlYTH2-induced condensates. Through polysome profiling assays and proteomic analysis, we demonstrate that knockout of SlYTH2 expedites the translation process of SlHPL and SlCCD1B, resulting in augmented production of aroma-associated volatiles. This aroma enrichment significantly increased consumer preferences for CRISPR-edited fruit over wild type. These findings shed light on the underlying mechanisms of m6A in plant RNA metabolism and provided a promising strategy to generate fruits that are more attractive to consumers.

Salivary β-glucosidase as a direct factor influencing the occurrence of halitosis

β-Glucosidases are enzymes present in all living organisms, playing a pivotal role in diverse biological processes. These enzymes cleave β-glycosidic bonds between carbohydrates, or between a carbohydrate and a non-carbohydrate moiety, which may result in the liberation of volatile aglycones. Released compounds execute diverse physiological roles, while the industry takes advantage of exogenously added β-glucosidases for aroma enrichment during food and beverage production. β-Glucosidase enzymatic activity has been reported in human saliva and given the fact that these enzymes are involved in aroma release, we investigated here the correlation between β-glucosidase activity in human saliva and the occurrence of halitosis. Measurement of salivary enzyme activity of 48 volunteers was performed using p-nitrophenyl-β-d-glucopyranoside as substrate. Each volunteer was clinically evaluated by a dental surgeon and clinical and laboratorial data were statistically analyzed. Gas-chromatography of saliva headspace allowed the analysis of the direct role of exogenous β-glucosidase on aromatic /volatile profile of saliva samples. The data demonstrated a positive correlation between halitosis and enzymatic activity, suggesting that the enzyme exerts a direct role in the occurrence of bad breath. Gas-chromatography analysis demonstrated that exogenously added enzyme led to the alteration of volatile organic content, confirming a direct contribution of β-glucosidase activity on saliva volatile compounds release. Although halitosis is a multifactorial condition, the complete understanding of all governing factors may allow the development of more effective treatment strategies. Such studies may pave the way to the use of β-glucosidase inhibitors for halitosis clinical management.

Encapsulation of orange and lavender essential oils in chitosan nanospherical particles and its application in leather for aroma enrichment

Incorporating “smartness” into leathers leads to enormous value addition. One such smartness is development of scented leather. Lavender and orange oils have been microencapsulated and infused into the leather. Viscosity, opacity, and transmittance have been measured in order to optimize oil: surfactant ratio. Emulsion polymerization technique has been adopted for encapsulation of scent oils using chitosan as wall material. Percentage encapsulation efficiency, oil load and content have been studied for the encapsulated products. Lavender oil encapsulates hold better oil content and loading than orange oil encapsulates. Further, encapsulates have been characterized using particle size, surface morphology, FT-IR and TGA and results were corroborating. The encapsulated product withstands high temperature up to 500 °C and also it also shows antimicrobial activity. Encapsulated scent oils have been incorporated into leather and subjected to perception, strength, washability and diffusion coefficient studies. Thus, successful value addition to leather through incorporating of pleasant smell has been made possible resulting in “smart scented” leathers.

Effects of sucrose monopalmitate (P90), Tween 80 and modified starch on coffee aroma retention and release in coffee oil-based emulsions

Despite the convenience and extended shelf life of instant coffee, its aroma profile is less desirable compared to freshly brewed coffee. The objective of this study was to evaluate the effects of sucrose monopalmitate (P90), modified starch (MS) and Tween 80 on coffee aroma retention and release in oil-in-water emulsion matrices (coffee oil as the flavor matrix) and upon spiking into instant coffee, with an aim to enrich instant coffee aroma. The volatile profiles of P90-, MS- and Tween 80-stabilized coffee emulsions before, after freeze-drying and upon spiking into instant coffee were characterized with HS-SPME-GC-MS/FID and compared. The extent of volatile retention and release varied with the type of emulsifiers and volatile classes. Aldehydes and phenolic compounds levels in P90-stabilized coffee emulsions were 40% and 30% significantly lower compared to the control while their levels in Tween 80-stabilized coffee emulsion were 8% and 38% lower compared to the control respectively. Phenolic compounds levels in MS-stabilized coffee emulsion were 13% significantly lower compared to the control. Volatile retention remained after freeze-drying for P90- and Tween 80-stabilized coffee emulsions where total volatile levels were 12% and 25% significantly lower compared to the controls, respectively. The total volatiles levels of instant coffees spiked with P90- and MS-stabilized coffee emulsions were higher compared to the blank and spiking with the controls. The trend was reversed when Tween 80-stabilized coffee emulsion was spiked. Therefore, P90- and MS-stabilized coffee emulsions exhibited some extent of controlled aroma release and could be utilized for instant coffee aroma enrichment.

Assessment of β-d-glucosidase activity of intact cells of two Oenococcus oeni strains with synthetic and natural substrates

The β-d-glucosidase (βG) activity of intact cells of Oenococcus oeni SD-2a and 31MBR was assessed with synthetic and natural substrates, also its partial characterisation was investigated. Results showed that intact cells of both strains showed βG activity, SD-2a performing higher than 31MBR, against either synthetic or natural substrate. The high βG activity of SD-2a intact cells under wine-like temperature, pH, ethanol concentration, and glucose concentration could be of great interest for its utilisation in winemaking. SD-2a proved promising for aroma enrichment in winemaking.

Arginase inhibition, antibacterial and antioxidant activities of Pitanga seed (Eugenia uniflora L.) extracts from sustainable technologies of high pressure extraction

Abstract Pitanga seed extracts from supercritical extraction (SFE), pressurized liquid extraction (PLE) and conventional Soxhlet extraction had their bioactive properties tested in vitro. The essays included antioxidant (reducing power, DPPH • and ABTS •+ ) and antibacterial ( S. aureus , E. coli , P. aeruginosa and B. subtilis ) activities, as well as the arginase enzyme inhibition test. Purified PLE extracts presented the highest antioxidant capacity (33.37 µM Trolox×g −1 extract) and arginase inhibition (75.96%). All extracts presented the same value of minimum concentration inhibition, 125 µg×g −1 , indicating high antibacterial potential. The purified fractions from extracts obtained using SFE and PLE processes had increased arginase from Leishmania inhibition, 48.48% and 75.96% respectively, compared to Soxhlet (37.59%). These findings suggest that using different extraction methods on Pitanga seed can produce compounds with diverse activities. Extracts from Pitanga seed, a residue from the juice processing industry, possess characteristic fruit volatiles and could be used as natural aroma enrichment of Pitanga products or in functional foods formulations since compounds of the extracts present bioactive activities.

Aroma compound recovery by hydrophobic pervaporation: The effect of membrane thickness and coupling phenomena

In this study, pervaporation experiments were performed with binary and ternary model solutions of pomegranate aroma compounds to investigate the effect of membrane thickness and coupling phenomena on the permeation flux and aroma enrichment factors. Various composite POMS and PDMS membranes were tested for pervaporation and compared for their separation performance. In order to evaluate the significance of mass transfer resistance in the boundary layer with respect to the mass transfer resistance in the membrane, experiments were carried out using membranes with different thickness. The results showed that the permeation flux through both membrane types decreased markedly with increasing the membrane thickness, while the aroma compound enrichment factors increased. Coupling effects was qualitatively evaluated by comparing the aroma partial flux from the binary and ternary feed solutions. It was observed that the permeation of some aroma compounds was affected by presence of other aroma compounds.

Impregnation Techniques for Aroma Enrichment of Apple Sticks: A Preliminary Study

The food industry often utilizes flavor-enriched, semifinished food products as ingredients in more complex preparations. To the best of our knowledge, there are no methods to produce minimally processed food items to which flavorings have been added. In this investigation, apple sticks were enriched with a green apple aroma using different techniques. In particular, vacuum impregnation (VI), ultrasound technology (USI), and the combination of these two techniques (VUSI) were compared with atmospheric pressure impregnation (AI). An isotonic solution of fructose containing ascorbic acid and green apple flavoring was used for impregnation of apple sticks. Different treatment times (2.5, 5.0, and 12.5 min) were investigated, and the relative amount of the major compounds of impregnation flavoring was recorded. Significant differences between treatments were detected: VI and VUSI gave the highest aroma enrichment at 5.0 min of treatment. Different impregnation behaviors were recorded for alcohols and esters: the former increased even after 5.0 min of treatment, and the other components increased until 5.0 min and then decreased, mainly when ultrasound was applied (USI and VUSI). Some possible explanations of these results are proposed, although additional studies are needed to explain the mechanisms involved.

Vacuum membrane distillation of the main pear aroma compound: Experimental study and mass transfer modeling

In this work, the recovery of the main pear aroma compound, ethyl 2,4-decadienoate, by means of vacuum membrane distillation is studied. A commercial hollow fiber module of polypropylene (PP) microporous membranes and a model solution of ethyl 2,4-decadienoate in ethanol–water mixtures were used in the experimental study. The effect of the operating variables, aroma feed concentration, feed flow rate, temperature and downstream pressure onto the process performance was analysed. Aroma enrichment factors up to 15 were experimentally obtained. A strong and reversible sorption of the aroma compound onto the PP material was observed. This phenomena was characterized by a linear adsorption isotherm, q a = K ads C a e , where K ads(295.96 K) = 0.27 kg kg −1 m 3 kg −1. A mathematical model able to predict the kinetics of the components separation and the partial component fluxes and enrichment factors was developed. In this model the classical gas transport mechanisms through the membrane pores, i.e. Knudsen and molecular diffusion, together with the sorption-diffusion phenomenon through the non-porous membrane portion, expressed by means of the surface diffusivity, were considered. The surface diffusivity of ethyl 2,4-decadienoate on the polypropylene was estimated to be D a s = 1.01 × 10 − 11 m 2 s − 1 at 296 K.

Multicomponent pervaporation process for volatile aroma compounds recovery from pomegranate juice

The present work describes the possibility of using pervaporation process to recover the pomegranate aroma compounds from an actual pomegranate juice and a model aroma solution. Four different chemicals representing four major kinds of aroma compounds, namely, 3-methyl butanal, isopentyl acetate, n-hexanol and α-ionone, were utilized in this work. Three POMS membranes and two PDMS membranes were tested for pervaporation and compared for their separation performance. The influence of various operating parameters such as feed flow rate, feed temperature and permeate pressure on the permeation flux and aroma compounds enrichment factor was investigated. Feed flow rate was shown to have no significant effect on both total flux and aroma enrichment factor, whereas feed temperature and permeate pressure had highly significant effects. An increase in feed temperature led to higher flux and enrichment factor. As permeate pressure increased, the flux and enrichment factor of some aroma compounds decreased. Some of the aroma compounds showed higher enrichment factor at higher permeate pressures. Finally, the activation energy of permeation and the membrane permeability for each aroma compound were determined.

Aroma enrichment and the change during storage of non-aromatic milled rice coated with extracted natural flavor

Three non-aromatic rice varieties (RD23, SPR1 and SPR90) were coated in a modified spouted bed with 30% sorbitol-plasticized rice-starch film containing 25% pandan ( Pandanus amaryllifolius Roxb.) leaf extract produced by the supercritical fluid with carbon dioxide extraction method. The coated and uncoated samples and uncoated aromatic rice (KDML and PTT1 varieties) were packed in plastic bags (nylon15/PE20/LLDPE75) and stored at 25 °C for 6 months. Gas chromatography–mass spectrometry analysis revealed that the coating treatment resulted to similar flavor volatile profile as that of aromatic varieties, particularly the presence of 2-acetyl-1-pyrroline (ACPY) which is the main volatile compound responsible for the jasmine aroma. ACPY was absent in uncoated non-aromatic rice and ACPY content of non-aromatic rice coated with natural pandan extract was lower than that of uncoated aromatic rice. During storage, ACPY levels decreased. Coated non-aromatic rice retained higher ACPY levels than the aromatic PTT1 variety. The coating treatment also reduced the n-hexanal content of stored grains. Thus, the coating technique is a promising approach for rice aroma improvement and at the same time, for reducing the potential for oxidative rancidity during grain storage.

Changes in the composition of volatiles by post‐harvest application of alcohols to red delicious apples

AbstractThe effect of exogenous short‐chain n‐alcohols on the concentrations of main aroma components in mature intact Red Delicious apples and aged apple tissue discs has been studied. Storage of intact apples in an atmosphere containing ethanol vapours for 24 h resulted in a more than threefold increase in the sum of ethyl ester concentrations. The simplified model of tissue discs was applied to examine the influence of various ethanol concentrations on rate and time course of ester formation. On supplying a range of n‐alkan‐1‐ols and 2‐keto valeric acid in equimolar amounts to the discs, maximum conversion into esters was found with butanol and pentanol. The possibility of an in vivo aroma enrichment before processing of fruits is discussed.

The quantitative composition of natural and technologically changed aromas of plants. II. Aroma compounds in oranges and their changes during juice processing (author's transl)

After enzyme inhibition with methanol the original volatile compounds of the fruits were investigated in order to compare the quantitative composition of the aroma substances in orange fruits and juices. Aroma compounds of fresh, flash pasteurized and pasteurized juices were analysed. After aroma enrichment by liquid-liquid extraction, prefractionation of the flavor compounds by column chromatography on silicagel 56 flavor substances in the fruits and in the different juices were identified and determined by gas chromatography and mass spectrometry. In comparison to their content in the fruits only 10% of the terpenic hydrocarbons and about 30-66% of the esters were found on average in the fruits. Among the secondary flavor substances, which were not present or present only in traces in the fruits, but showed in juices concentrations up to 0,2 ppm, were 4-terpinenol, carveol and tr-2,8-menthadien-1-ol. After a thermic treatment also 3-hydroxy-2-butanone and 3-methyl-2-buten-1-ol were identified.