Concentration Of Aroma Compounds Research Articles

Introducing CCD1 into isolated Rhodotorula strain enhances flavor production and improves cigar fermentation

IntroductionThe fermentation process plays an important role in enhancing the quality of cigar tobacco leaves. Through fermentation, microbial metabolism can degrade aromatic precursors and macromolecules, which increases the content of aroma compounds and reduces irritancy of tobacco leaves.MethodsTo further enhance the fermentation effect of cigar tobacco leaves, a Rhodotorula strain (Rh3), capable of producing carotenoids and improving fermentation quality, was isolated from cigar tobacco leaves. Subsequent genetic engineering techniques introduced the carotenoid cleavage dioxygenase 1 (CCD1) gene into the isolated Rh3.ResultsThe modified Rh3 exhibits a significant increase in carotenoid degradation products compared with the original Rh3 in culture medium (from 0.29 μg/mg to 15 μg/mg). Subsequent cigar tobacco leaf fermentation experiments revealed that the modified Rh3 produced 65.9% more carotenoid degradation products compared to the control group, outperforming the original strain, which achieved a 41.4% increase. Furthermore, the modified strain preserves its ability to improve the intrinsic chemical composition of cigar tobacco leaves.DiscussionWe show here that modified Rh3 can increase the content of carotenoid degradation products, thereby enhancing the fermentation effect of cigar tobacco leaves. This study presents a beneficial exploration to improve the quality of cigar tobacco leaves for future use and offers a promising strategy for producing flavor compounds from discarded tobacco leaves.

Exploring the evolution of sugars and volatile compounds in Marselan grape berries under water stress

The coordination between sugar and aroma compounds concentration in grape berries under water stress still unclear. Here, the field grown ‘Marselan’ (Vitis vinifera L.) vines were submitted to two levels of water stress (T1: −0.40 MPa ≤ ΨPD < −0.20 MPa; T2: −0.60 MPa ≤ ΨPD < −0.40 MPa) from 20 to 120 days after anthesis across two consecutive vintages (2021, 2022). The concentration of bound aroma compounds was promoted at ripe stage under T1, with a particularly significant increase in bound higher alcohols. In the PCA analysis, we found that the influences caused by weather conditions between two vintages were larger than those between treatments, the cooler weather promoting the concentration of aroma compounds. According to the OPLS-DA analysis, the concentration of bound benzyl alcohol, 1-heptanol, α-terpineol, 1-octen-3-ol and 1-hexanol was closely related to that of sugar. Furthermore, T1 promoted the expression of sugar transporters, glycosyl transferase and higher alcohol concentration at the veraison stage; in particular, the expression of VvSUC12 was highly correlated with the concentration of bound alcohols. Taking all findings into consideration, T1 could be more favorable to increase the bound alcohols concentration by upregulating the β-D-glucose transport.

Characterization of Changes in Ripening Process of Volatile Apple Compounds Based on HS-SPME-GC-MS Analysis

The aim of this study was to identify the aromatic compounds present in different apple varieties and to gain insights into the changes in the aromatic compounds during ripening. Three apple varieties (“Red Astrachan”, “Ning Qiu”, and “Golden Delicious”) at different stages of ripening were selected for this study; their peel and pulp were analyzed via headspace solid-phase microextraction (HS-SPME)–gas chromatography–mass spectrometry (HS-SPME-GC-MS), and 30 volatile compounds were identified. The samples’ differences were analyzed using heat map cluster analysis, principal component analysis (PCA), and an independent samples t-test. The results showed that the content of aromatic compounds in the peel was higher than that in the pulp. The relative content of esters in the aromatic compounds of the three apple varieties followed the order of pulp &gt; peel and “Ning Qiu” &gt; “Golden Delicious” &gt; “Red Astrachan”. This suggests that “Ning Qiu” combines the advantages of its parents in terms of its aroma content. The highest concentrations of aroma compounds in “Red Astrachan” and “Ning Qiu” accumulate before the ripening stage, and care should be taken to choose an appropriate harvesting time according to the different needs during production. The main compounds of “Red Astrachan” are aldehydes and C8 esters, while those of “Ning Qiu” and “Golden Delicious” are alkenes and esters. After analyzing the relative odor activity values (rOAVs) of key volatile compounds and their aroma descriptors during the harvest period, acetic acid pentyl ester, butanoic acid hexyl ester, hexanoic acid hexyl ester, and 2-ethyl-1-Hexanol were found to contribute the most to the overall flavor of the peel and pulp. “Ning Qiu” combines the parental advantages of the concentrated peel of “Red Astrachan” and the astringent pulp of “Golden Delicious”, with compounds in its composition that give a pleasing aroma. Mature “Ning Qiu” fruits have a more intense aroma and fruity flavor. The development of flavor-specific varieties has provided the theoretical basis for future research in molecular hybridization, molecular-assisted breeding, and the molecular biology of apple flavor synthesis and metabolism.

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.

Unlocking the potential of Kluyveromyces marxianus in the definition of aroma composition of cheeses.

The cheese microbiota is very complex and is made up of technologically-relevant, spoilage, opportunistic and pathogenic microorganisms. Among them lactic acid bacteria and yeasts are the main ones. One of the most interesting dairy yeasts is Kluyveromyces marxianus because of its technological properties including the ability to produce aroma compounds. This study investigated the contribution of Kluyveromyces marxianus to the gross composition and aroma profile of cow cheeses. Experimental cheeses were prepared by inoculating a co-culture of K. marxianus FM09 and a commercial strain of Lacticaseibacillus casei and compared with cheeses obtained with only L. casei. The gross composition was determined by a FoodScan™ 2 Dairy Analyser, and free amino acids were evaluated at 507 nm after reaction with Cd-ninhydrin. The volatile organic compounds were extracted by head-space solid phase micro-extraction and analyzed by gas chromatography-mass spectrometry coupled with odor activity values. qRT-PCR was applied to determine the expression of genes involved in esters synthesis and degradation. The inoculation of K. marxianus induced an increase of pH and a reduction of protein content of cheeses, in agreement with the stronger proteolysis detected in these cheeses. K. marxianus influenced the content of aroma compounds both quantitatively and qualitatively. In particular, an increase of higher alcohols, esters and organic acids was observed. Moreover, 12 compounds were detected only in cheeses obtained with the co-culture. These differences were in agreement with the odor activity values (OAV). In fact, only 11 compounds showed OAV > 1 in cheeses obtained with the commercial strain, and 24 in those obtained with the co-culture. The qPCR analysis revealed an over expression of ATF1, EAT1, and IAH1 genes. Kluyveromyces marxianus could act as an important auxiliary starter for cheese production through the development and diversification of compounds related to flavor in short-aged cow cheeses.

Enhancing variety aromatic characteristics of Muscat wine through cold maceration with indigenous cryotolerant Metschnikowia pulcherrima Mp0520

Cold maceration (CM) is widely applied in winemaking to improve wine aroma and overall quality. However, more efficient CM techniques for industrial-scale winemaking are still needed. This study examined the impact of CM with indigenous cryotolerant Metschnikowia pulcherrima Mp0520 (Mp-CM) on the Muscat wine aromatic characteristics. The results demonstrated a significant divergence in the types and concentrations of aroma compounds between Mp-CM wine and the control. The Mp-CM wine exhibited a significantly higher terpenes content, resulting in a Muscat wine characterized by terpenes, compared to the control predominated by esters. Additionally, the Mp-CM wine demonstrated elevated levels of α-terpineol and terpinolene, potentially enhancing the varietal aroma stability of Muscat wine. Furthermore, Mp-CM gave Muscat wine a heightened fruity aroma and a more complex aroma. These findings suggested that the Mp-CM utilized in this study offered promising avenues for enhancing the variety aroma characteristics of Muscat wine on large scale winemaking.

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.

Volatomic differences among Vitis amurensis cultivars and its hybrids with V. vinifera revealed the effects of genotype, region, and vintage on grape aroma

Vitis amurensis grape, an East Asian Vitis species, has excellent cold and disease resistance and exhibits high winemaking potential. In this study, the aroma compounds in grapes from five V. amurensis cultivars (‘Beiguohong’, ‘Beiguolan’, ‘Shuangfeng’, ‘Shuanghong’, ‘Shuangyou’) and three interspecific hybrids (‘Beibinghong’, ‘Xuelanhong’, ‘Zuoyouhong’) from two regions (Zuojia and Ji’an, Jilin, China) were identified via HS-SPME-GC/MS. The results showed that V. amurensis grapes had a greater concentration of aroma compounds than the interspecific hybrid berries. ‘Beibinghong’ was relatively rich in terpenes, although their concentrations were all lower than the threshold. ‘Shuangfeng’ contained more concentrations of free C6/C9 compounds, alcohols, aromatics and aldehydes/ketones than the other cultivars. The aroma characteristics of ‘Beiguolan’ and ‘Shuanghong’ were relatively similar. The grapes from the lower temperature and more fertile soil of Zuojia contained more C6/C9 compounds, norisoprenoids and alcohols, while aromatics were more abundant in the grapes from Ji’an, which was warmer than the Zuojia region. Herbaceous, floral, fruity and sweet were the main aroma series of V. amurensis grapes. Our study could provide a reference for the development and utilization of V. amurensis grapes and lay a foundation for the development of wild grape cultivars and the production of wines with characteristic styles.

Development and characterization of Japanese soy sauce-like fermented seasoning with various ingredients

Ten types of ingredients, including pressed barley, sprouted brown rice, red sorghum, amaranth, glutinous millet, upland rice, rice bran, chickpeas, rapeseed pomace, and perilla pomace, were utilized to develop a soy sauce-like seasoning. Free amino acid, aroma compound, and sensory evaluation values were measured in comparison to regular soy sauce (fermented with soybean and wheat). The content of free amino acids was highly correlated with the total nitrogen content, with regular soy sauce showing the highest value. The taste attribute amino acids levels were also high in regular soy sauce, rapeseed pomace, and perilla pomace, which attributed to a rich flavor. Except for sprouted brown rice and pressed barley, the remaining nine seasonings exhibited distinctive or elevated content of aroma compounds. Sensory evaluation separated eleven seasonings into sprouted brown rice, together with upland rice, and the rest. PLSR analysis identified sixteen free amino acids as flavor key contributors and twenty-four key aroma contributors. Among the eleven types of seasoning, regular soy sauce was characterized by a sweet and umami taste, while rapeseed pomace was predominantly bitter. The aroma of regular soy sauce was mainly derived from grains and tea, whereas rapeseed imparted distinctive flavors of broth smell and a fragrant aroma.

Study on the Effect of Different Concentrations of SO2 on the Volatile Aroma Components of 'Beibinghong' Ice Wine.

SO2 plays an important role in wine fermentation, and its effects on wine aroma are complex and diverse. In order to investigate the effects of different SO2 additions on the fermentation process, quality, and flavor of 'Beibinghong' ice wine, we fermented 'Beibinghong' picked in 2019. We examined the fermentation rate, basic physicochemical properties, and volatile aroma compound concentrations of 'Beibinghong' ice wine under different SO2 additions and constructed a fingerprint of volatile compounds in ice wine. The results showed that 44 typical volatile compounds in 'Beibinghong' ice wine were identified and quantified. The OAV and VIP values were calculated using the threshold values of each volatile compound, and t the effect of SO2 on the volatile compounds of 'Beibinghong' ice wine might be related to five aroma compounds: ethyl butyrate, ethyl propionate, ethyl 3-methyl butyrate-M, ethyl 3-methyl butyrate-D, and 3-methyl butyraldehyde. Tasting of 'Beibinghong' ice wine at different SO2 additions revealed that the overall flavor of 'Beibinghong' ice wine was the highest at an SO2 addition level of 30 mg/L. An SO2 addition level of 30 mg/L was the optimal addition level. The results of this study are of great significance for understanding the effect of SO2 on the fermentation of 'Beibinghong' ice wine.

Brown rice protein–dietary fibre conjugate improves bioaccessibility of minerals via modifying gelling structure of yoghurt

SummaryThe present study aims to provide an overview of the impact of brown rice protein (BRP) conjugated with microcrystalline cellulose via the Maillard reaction on characteristic features of yoghurt and the bioaccessibility of essential minerals in this dairy product. The confirmation of conjugation was conducted using FTIR spectroscopy. Adding BRP or Maillard conjugate (MC) proved beneficial in enhancing the water‐holding capacity and decreasing the syneresis of samples. Additionally, yoghurt (MCY) containing the Maillard conjugate demonstrated superior performance in these properties. A lower number of pores and a stronger gel network (structural integrity) were identified in MCY compared to the other samples (BRPY: yoghurt containing BRP and PY: plain yoghurt). On the other hand, in general, supplementation of BRP and MC led to slight alteration in the concentration of aroma compounds. Similarly, the impact of BRP and MC on changes in the molecular weight distribution of proteins during in vitro gastrointestinal digestion was negligible. Bioaccessibility values of Ca and Mg in PY were 53.72% and 10.72%, respectively. The improvement in these values was observed in BRPY (Ca: 57.33% and Mg: 15.60%). Moreover, adding MC to yoghurt led to a tighter interface structure (indicating rigid gel), which allowed more minerals to bind, increasing mineral bioaccessibility (Ca: 64.40% and Mg: 31.14%). A higher general acceptability in sensory evaluation was scored for PY followed by MCY and BRPY. Ultimately, the positive effect of ingredients (especially MC) on yoghurt quality was obvious.

Effects of processing methods on the aroma of Poria cocos and its changing regulations during processing

Poria cocos is a natural source of fungal food raw materials. Processing method is a key effecting the aroma of Poria cocos. In this study, the aroma compounds of Poria cocos products processed using sweating-low-temperature drying (SW-LD), sweating-high-temperature drying (SW-HD), steaming-low-temperature drying (ST-LD), and steaming-high-temperature drying (ST-HD) were compared by headspace solid-phase microextraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC–MS), and the changes in aroma compounds of Poria cocos products during processing were analyzed. GC–MS analysis showed SW-HD product had highest content of aroma compounds. Aroma activity value (OAV) analysis indicated that 9 aroma compounds contributed to the overall aroma of Poria cocos. Among 9 compounds of Poria cocos, 1-octen-3-ol, hexanal, nonanal, octanal, trans-2-octenal, and heptanal contributed to mushroom, refreshing, sweet and fatty characters. In addition, the aroma compound changes during the processing were analyzed, revealing that steaming and sweating were the key processes affecting the aroma of Poria cocos products. The findings of this study provide valuable theoretical guidance for the development of Poria cocos processing technology.

The role of fines in espresso extraction dynamics

The impact of particle size distribution of coffee grounds on espresso extraction was explored. Finely ground coffee for espresso has a characteristically bimodal particle size distribution. For a given median grind size, different grinding technologies can yield a different share of fines (particles < 100 µm). We performed espresso extractions for a range of median particle sizes and systematically varying the share of fines by adding sieved fines to the coffee grounds. Dynamic beverage weights, extraction percentage, extraction time and dynamic headspace PTR-MS (proton-transfer mass spectrometer) analysis and sensory evaluation of the resulting brews were measured. We show that the share of fines plays a key role in the espresso extraction flow rate. An increase of share of fines decreases coffee bed permeability, leads to reduced flow rates and longer extraction times. A statistical model using partial least squares regression of the particle size distributions of coffee grounds confirms that fines decrease the coffee bed permeability. The PTR-MS analysis shows a non-linear increase of aroma compounds in the cup with increasing extraction yield. Our hypothesis is that both extraction efficiency and post-extraction evaporative losses of aroma compounds influence the final aroma compound concentrations in the cup.

A test-tube vinification method for high-throughput characterisation of the oenological and aromatic potential of white wines

The quality of wine largely depends on aroma perception, but the genetic basis explaining the variations of aroma compound concentrations in wines is still fragmentary. To unravel links between genetic variations and aroma compound variations in hundreds of genotypes, we developed a small-scale, high-throughput test-tube vinification (TTV) method capable of producing white wines that reveal the genetic potential at the scale of a single vine stock. We evaluated this method on commercial grapevine varieties (Riesling, Gewurztraminer, Chardonnay, Chasselas, Floreal, Muscat à petits grains blancs) and genotypes resulting from a bi-parental cross, covering a wide aromatic palette. The wines produced were described by usual oenological parameters and GC-MS profiling of volatile compounds. We compared the wines obtained with the TTV method to commercial wines and to wines obtained from larger fermentation volumes (5–10 L). Our results show that the TTV method is suitable to produce white wines on a very small scale, i.e., less than 100 mL and that these small-scale wines faithfully reflect the aromatic potential of the different varieties, as would larger volume methods. The proposed method is a high-throughput approach to assess the oenological potential of hundreds of grapevine genotypes from grape material harvested on a single vine. This wine-focused direct phenotyping method will pave the way for a better understanding of the genetic determinism of wine aromas, especially for molecules that are not directly present in grapes, such as volatile thiols and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN).

Integrated Analysis of Transcriptome and Metabolome to Unveil Impact on Enhancing Grape Aroma Quality with Synthetic Auxin: Spotlight the Mediation of ABA in Crosstalk with Auxin.

It is widely accepted that prevéraison application of naphthaleneacetic acid (NAA) can delay the ripening of grapes and improve their quality. However, how NAA impacts grape aroma compound concentrations remains unclear. This study incorporated the analyses of aroma metabolome, phytohormones, and transcriptome of Vitis vinifera L. cv. Cabernet Sauvignon grapes cultivated in continental arid/semiarid regions of western China. The analyses demonstrated that NAA application increased β-damascenone and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) in the harvested grapes by delaying véraison and upregulating VvPSY1 and VvCCD4b expressions. Additionally, NAA treatment decreased 2-isobutyl-3-methoxypyrazine (IBMP) at the same phenological stage. Notably, abscisic acid (ABA) levels increased in NAA-treated grapes during véraison, which triggered further changes in norisoprenoid metabolisms. The ABA-responsive factor VvABF2 was potentially involved in VvPSY1 positive modulation, while the auxin response factor VvARF10 may play a role in VvCCD4b upregulation and VvOMT2 downregulation during NAA induction. VvARF10 possibly acts as a crosstalk node between the ABA and auxin signaling pathways following NAA treatment in regulating aroma biosynthesis.

Identification of aroma compounds responsible for apple flavor via palatability score prediction in tree-based regression models

Apple flavor has been linked to the composition of aroma compounds; however, the impact of varying concentrations of aroma compounds remains poorly understood. While sensory evaluation is commonly used to analyze food palatability, assessing the effect of concentration of all aroma compounds poses challenges. This study screened 174 apple genotypes for significant aroma compounds using regression models, Gas chromatography–mass spectroscopy analysis, and sensory palatability scores. Two models viz. Random Forest and XGBoost were employed to predict palatability scores, surpassing the limitations of correlation analysis. Shapley's additive explanatory value analysis identified 5-hexenol, ethyl 2-methyl butyrate, 2-methylbutyl acetate, (E,E)-α-farnesene, and (Z)-3-hexenol as key aroma compounds. In a sensory evaluation validating the effect of aroma compound concentration, the variation in (E,E)-α-farnesene concentration negatively affected sensory palatability scores. This study demonstrated a novel approach for identifying aroma compounds that impact apple flavor, providing valuable insights to enhance apple quality and palatability.

Characterization of key aroma compounds in Rice flavor baijiu from different rice raw materials by gas chromatography-ion mobility spectrometry and gas chromatography-olfactometry-quadrupole time of flight mass spectrometry

Rice flavor baijiu is one of the four traditional Chinese liquors, but the flavor difference caused by rice raw materials has received little attention. In this study, gas chromatography-ion mobility spectrometry (GC-IMS) combined with gas chromatography-olfactometry-quadrupole time of flight mass spectrometry (GC-O-QTOF/MS) were used to analyze five Rice flavor baijiu brewed from different rice raw materials. The results showed that there was a significant difference in the number and content of aroma compounds between the baijiu made from japonica rice and indica rice, and a total of 34 volatiles were characterized by the GC-IMS technique, which effectively constructed the fingerprint profile of the flavor differences of Rice flavor baijiu. GC-O-QTOF combined with aromatic extract dilution analysis (AEDA) tests identified 42 characteristic aroma active regions, 34 of which could be identified and quantified by the internal standard method. Sixteen aroma-active compounds in five baijiu samples showed high odor activity values (OAV). In addition, multivariate statistical analyses such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) effectively revealed the distribution patterns of the samples and their separation of relevant aroma activity markers. Six key aroma compounds, including isopentyl acetate, ethyl hexanoate, benzeneacetaldehyde, phenethyl acetate, undecane-2-one, and ethyl decanoate, were screened to have a greater effect on the flavor of Rice flavor baijiu.

Development of a New Method for the Quantitative Analysis of Aroma Compounds Potentially Related to the Fruity Aroma of Red Wines.

To determine the concentrations of aroma compounds involved in the fruity aroma of red wines, an analytical method was developed and optimized using liquid-liquid extraction and gas chromatography coupled to mass spectrometry (GC/MS). The aim was to reduce sample preparation and analysis time, with a single sample preparation and a single injection being needed to quantify 43 compounds. 19 esters, 13 monoterpenes, 5 C13-norisoprenoids, and 6 C6-aldehyde and alcohol compounds were quantified in 14 red wines made from different grape varieties grown in the Mediterranean basin. Samples were selected based on typical varietal aroma by a panel of experts, who produced 7 olfactory descriptors linked to desirable or non-desirable wine aromas. The instrumental analysis showed variations in concentrations of the quantified compounds among the wines. The wines described using positive fruity descriptors had higher mean total concentrations of esters, C6-alcohols, monoterpenes, and C13-norisoprenoids. Some non-ester compounds were positively correlated with the fruity descriptors. Sensory profile results obtained by a panel of 16 trained judges revealed that the addition of non-ester compounds (including 2 cyclic esters) to a red wine initially described as having cooked fruit aromas had a positive contribution to some fresh fruity notes. This study opens up new avenues for research on the potential involvement of non-ester compounds in the fruity expression of red wines.

Comparison of the effects of oven‐ and microwave‐roasting on the physicochemical properties and bioactive compounds of tomato seeds and oils

AbstractThe tomato processing industry generates a significant amount of a by‐product (pomace), which is a mixture of peels and seeds. The purpose of this study was to compare the effects of conventional oven‐roasting (at 120°C, 150°C, and 180°C for 25 min) and innovative microwave‐roasting (at 240, 388, and 536 W for 3 min) pretreatments on the physicochemical properties, fatty acid profiles, bioactive contents, and aroma profiles of tomato seeds and their hexane‐extracted oils. The total flavonoids contents (TFCs) of the seeds decreased from 258.40 to 141.20 mg quercetin equivalent (QE) per kg after roasting. All roasting treatments improved the extractability of both α‐ and γ‐tocopherols. The amounts of total tocopherols in the seeds increased from 917.61 to 1256.25 mg kg–1 after pretreatment. Luteolin was found to be the most abundant phenolic in seed oils, increasing from 10.68 to 91.72 mg kg–1, followed by quercetin, ferulic acid, and catechin. Within each roasting technique, the ones treated at 150°C and 338 W yielded the oils with the highest concentrations of aroma compounds, 418 and 92 mg kg–1, respectively. The detrimental effect of microwave‐roasting on these compounds was more pronounced. In conclusion, microwave‐roasting at shorter times than conventional roasting produced tomato seed oils with well‐preserved bioactive components and few unfavorable changes.Industrial relevance: Conventional oven‐roasting has been widely applied to oilseeds to improve oil yield as well as to obtain desirable sensory characteristics of extracted oils for years. However, longer roasting times may also cause detrimental changes in the properties of oils. On the other side, microwave‐assisted applications as an emerging technology provide homogenous and well‐controlled heat distribution, shorter treatment times, and considerable energy savings for the processing of various foods. Microwave technology has been easily scaled up and is currently employed for sterilization, drying, pasteurization, precooking, and extraction by the food and chemistry industries. Therefore, the present research suggests the use of microwaves for comparatively short roasting times to produce edible oils with enhanced physicochemical attributes and bioactives contents, and well‐maintained sensory properties. This promising innovative technology has the potential to be industrialized for a cost‐effective seed roasting process.

Effect of Herbal Feed Additives on Goat Milk Volatile Flavor Compounds.

The aim of this study is to investigate the effects of herbal supplements administered to goats on sensory quality and volatile flavor compounds in their milk. The experiment was conducted on sixty Polish white improved goats randomly allocated into five feeding groups (four experimental and one control) of twelve goats each. The trial lasted 12 weeks. The experimental animals received supplements containing a mixture of seven or nine different species of herbs at 20 or 40 g/animal/day. The control group received feed without any herbal supplements. Milk obtained from experimental and control groups of animals was characterized by a low content of aroma compounds, with only 11 chemical compounds being identified. Decanoic methyl ester, methylo 2-heptanone and methylo-butanoic methyl ester had the highest share in the total variability of the tested aroma compounds (PCA). During the sensory evaluation, the smell and taste of most of the samples were similar (p > 0.05). However, the addition of herbal feed supplements lowered the concentration of Caproic acid (C6:0), Caprylic acid (C8:0) and Capric acid (C10:0), which caused a significant reduction in the goaty smell of milk. The obtained results indicate that the studied herbal supplements can reduce the intensity of goaty smell and allow goat milk production without modification of other sensory features.