Odor Properties Research Articles

Effect of Artisanal Processing on Volatile Compounds and Sensory Characteristics of Traditional Soft-Ripened Cheeses Matured with Selected Lactic Acid Bacteria

The present research evaluated the effect of selected Lacticaseibacillus casei strains with anti-Listeria monocytogenes properties on the characteristics of traditional soft-ripened cheeses produced in two different seasons. Physicochemical, microbiological, texture, volatile compound, and sensory evaluations were performed on the cheeses after 60 days of ripening. The inoculation with protective cultures of selected LAB did not negatively affect the physicochemical parameters of the cheeses. Thirty-two volatile compounds were identified, including acids, alcohols, ketones, aldehydes, and esters, with differences between productions and inoculated batches. The selected LAB strains improved the sensory profile of the soft-ripened cheeses, decreasing values of texture parameters such as hardness, gumminess, and chewiness related to a softer texture and increasing umami taste and floral and lactic odor attributes. Sensory analysis revealed that consumers perceived differences between inoculated and non-inoculated cheeses, although the overall acceptability was not affected. This study provides valuable information for the artisanal cheese industry, demonstrating that it is possible to use selected protective lactic acid bacteria to assure food safety without compromising traditional flavor and even improving sensorial attributes.

Odor prediction of whiskies based on their molecular composition

Aroma compositions are usually complex mixtures of odor-active compounds exhibiting diverse molecular structures. Due to chemical interactions of these compounds in the olfactory system, assessing or even predicting the olfactory quality of such mixtures is a difficult task, not only for statistical models, but even for trained assessors. Here, we combine fast automated analytical assessment tools with human sensory data of 11 experienced panelists and machine learning algorithms. Using 16 previously analyzed whisky samples (American or Scotch origin), we apply the linear classifier OWSum to distinguish the samples based on their detected molecules and to gain insights into the key molecular structure characteristics and odor descriptors for sample type. Moreover, we use OWSum and a Convolutional Neural Network (CNN) architecture to classify the five most relevant odor attributes of each sample and predict their sensory scores with promising accuracies (up to F1: 0.71, MCC: 0.68, ROCAUC: 0.78). The predictions outperform the inter-panelist agreement and thus demonstrate previously impossible data-driven sensory assessment in mixtures.

The Preharvest Application of Stress Response Elicitors Improves the Content of Bioactive Compounds without Modifying the Sensory Attributes of Butterhead Lettuce (Lactuca sativa var. capitata).

Using stress elicitors in fruits and vegetables is considered a good strategy to increase the content of bioactive compounds in plant foods. However, bioactive compounds can affect the sensory characteristics of food products, and little is known about their shelf-life stability in fresh produce treated with elicitors. In the present work, carotenoids and polyphenols were quantified by spectrophotometric methods in red and green butterhead lettuce treated with elicitors that had previously been demonstrated to increase bioactive compounds: arachidonic acid (AA), methyl jasmonate (MJ), and Harpin protein (HP). The bioactive compounds were determined immediately and during three weeks after harvest. A descriptive sensory analysis was carried out, which included odor, taste, tactile, and visual attributes of control and elicitor-treated lettuce. Carotenoids showed greater shelf-life stability than polyphenols, and both were more stable in red than in green lettuce during the first two weeks of storage. The best elicitor was MJ, which increased phenolic compounds (red and green lettuce), anthocyanins, and carotenoids (red lettuce) through the storage period. Color intensity, crispness, wettability, and bitter taste were some of the primary sensory attributes in butterhead lettuce and were not affected by any treatment. Other organoleptic properties were also not affected by the elicitors. These results suggest that elicitation could improve the content of bioactive compounds, which is stable through the shelf-life of butterhead lettuce, without any adverse effect on the sensory properties.

Identification of volatile and odor-active compounds in Maojian herbal tea (Dracocephalum rupestre Hance)

Maojian herbal tea originates from Xinzhou, Shanxi, China, and is renowned as one of the prominent northern Chinese herbal teas. However, the volatile and key odor-active compounds in Maojian herbal tea have not been reported. Using headspace-solid-phase microextraction coupled with gas chromatography–mass spectrometry, a total of 87 volatile compounds were identified. Thirteen aroma compounds were distinguished as the key odor-active compounds of Maojian herbal tea based on gas chromatography–olfactometry analysis, and odor activity values, including trans-β-ionone, cis-jasmone, β-caryophyllene, humulene, hexanal, nonanal, linalool, alloocimene B, β-cyclocitral, β-bourbonene, ylangene, δ-cadinene and indole. The results of partial least squares regression analysis demonstrate strong correlations between the odor-active compounds and odor properties. β-Caryophyllene is the main contributor to the woody aroma of Maojian herbal tea. The results of the present study offer a scientific insight into the aroma profile of Maojian herbal tea.

Comparative evaluation of sensory and instrumental flavor profiles of four edible microalgae: Spirulina platensis, Chlorella pyrenoidosa, Chlamydomonas reinhardtii, and Haematococcus pluvialis

Microalgae sensory features are an important parameter to consider in food applications. The current study comparatively evaluated the flavor profiles of four commercial edible microalgae species, i.e., Spirulina platensis, Chlorella proteinosa, Chlamydomonas reinhardtii, and Haematococcus pluvialis through sensory evaluation by a trained expert panel (n = 15) and chemical profiling of flavor compounds, with multivariate statistical methods used to correlate descriptive taste and odor analysis with non-volatile and volatile compounds. S. platensis displayed characteristic salty and umami tastes arising from inorganic ions and 5′-nucleotides, respectively, as well as “muddy” and “floral” odor attributes mainly associated with sulfur compounds and ketones. C. proteinosa and C. reinhardtii shared the taste attributes of sweetness and bitterness mainly contributed by free amino acids, as well as the odor attributes of “seaweed” and “mushroom” in association with aldehydes and alcohols. H. pluvialis had a typical sour taste owning to the presence of abundant organic acids, and smelled “fatty”, “phenolic”, “licorice”, and “fruity” due to aromatic ester and phenolic compounds. Overall, our results provide fundamental insights into the sensory features of common edible microalgae to guide future food applications.

Prediction on Air-Nasal Mucus Partition Coefficients of Odor Compounds.

The air-nasal mucus partition coefficient is a crucial property among all of the interaction mechanisms between odor molecules and olfactory receptors, since this property contributes to our sense of smell. Due to the complexity of the mucus composition, in vivo determination of the air-mucus partition coefficient is a technical challenge. A predictable model of the air-mucus partition coefficient can provide valuable insights into the chemical properties that govern olfactory perception and can help design desired odorants. In this study, we propose a novel model based on the deep-layer neural network (DNN) algorithm to predict the air-mucus partition coefficients for a range of odor compounds. The molecular surface charge density (σ-profile) calculated from the COnductor like Screening MOdel for Real Solvents (COSMO-RS) thermodynamic package was adapted as descriptors of structural features of odor molecules. The results revealed that the air-mucus partition coefficients are highly correlated to the σ-profile of the studied compounds. The information obtained from the study provided interpretable results, which not only help in identifying the molecular features that contribute to the air-mucus partition coefficient of odorants but also aid in the design of compounds with the desired odor properties.

Effects of Thymus vulgaris, Zataria multiflora, Salvia verticillata, and ε-polylysine on shelf-life extension of sweet basil leaves

ABSTRACT Due to basil’s short shelf life and the insufficient research on utilizing plant extracts and ɛ-polylysine as a natural preservative for vegetables, this research was to investigate different concentrations of plant extracts of Thymus vulgaris, Zataria multiflora, Salvia verticillata, and ε-Polylysine on increasing the shelf life of basil during cold storage at a temperature of 8°C over 12 days. All the treatments had less weight loss compared to the control group at the end of the storage period. ε-Polylysine (3 ml/L) and T. vulgaris (2 g/L) treatments effectively reduced spoilage symptoms by decreasing the activity of degrading enzymes like cellulase and polyphenol oxidase. Additionally, these treatments increased the activity of enzymes such as catalase, which inhibits the production of reactive oxygen species. By preserving phenolic compounds, antioxidant activity, ascorbic acid, and reducing microbial load, the ε-Polylysine (3 ml/L) and T. vulgaris (2 g/L) treatments extended the shelf life and quality of basil. The results indicate that using ε-Polylysine (3 ml/L) and T. vulgaris (2 g/L) treatments effectively preserved the sensory attributes of basil, including freshness, appearance, overall acceptability, and odor, throughout storage. Furthermore, these treatments reduced spoilage, extended shelf life, and improved the nutritional value of basil during storage.

Mechanisms underlying the formation of main volatile odor sulfur compounds in foods during thermal processing.

Volatile sulfur compounds (VSCs) significantly influence food flavor and garner considerable attention in flavor research due to their low sensory thresholds, diverse odor attributes, and high reactivity. Extensive research studies have explored VSC formation through thermal processes such as the Maillard reaction, thermal pyrolysis, oxidation, and enzymatic reactions. However, understanding of the specific reaction mechanisms and processes remains limited. This is due to the dispersed nature of existing studies, the undefined intermediates involved, and the complexity of the matrices and processing conditions. Given these limitations, the authors have shifted their focus from foods to sulfides. The structure, source, and chemical characteristics of common precursors (sulfur-containing amino acids and derivatives, thiamine, thioglucoside, and lentinic acid) and their corresponding reactive intermediates (hydrogen sulfide, thiol, alkyl sulfide, alkyl sulfenic acid, and thial) are provided, and the degradation mechanisms, reaction rules, and matrix conditions are summarized based on their chemical characteristics. Additionally, the VSC formation processes in several typical foods during processing are elucidated, adhering to these identified rules. This article provides a comprehensive overview of VSCs, from precursors and intermediates to end products, and is crucial for understanding the mechanisms behind VSC formation and managing the flavor qualities of processed foods.

Effect of a minimal processing route for the production of infant formulas on their sensory properties

Infant formulas (IFs), the sole adequate substitute to human milk, undergo several thermal treatments during production that can damage milk proteins and promote the formation of Maillard reaction products, modifying nutritional and sensory properties. The aim of this study was to determine the impact of a minimally processing route based on membrane filtration associated with different levels of heat treatment, on the odor, taste, texture and color attributes of IFs, then to compare with those of commercial milks. Three experimental IFs (produced with membrane filtration associated with low - T-, medium - T+, or high thermal treatments - T+++) were evaluated. Triangular tests conducted with a panel of 50 adults highlighted clear disparities between all the IFs. The same panel applied the Check-All-That-Apply method to evaluate the IFs: the range of variability between T- and T+++ was similar to that between the 2 commercial IFs, and the sensory characteristics of the experimental IFs were not far from the commercial brands for flavor and texture attributes. Analysis performed on the citation frequencies for each descriptor differentiated T-/T+ from T+++, but all the experimental IFs were described with positive sensory characteristics, unlike one commercial IF. Volatile organic compounds (VOCs) content of IFs with low and high thermal treatments were analyzed. Forty VOCs were identified by gas chromatography-mass spectrometry. T- contained a higher quantity of VOCs than T+++, except for benzaldehyde (Maillard reaction product), and aldehydes (oxidation-related products) were the most represented compounds. In conclusion, the processing was associated with sensory differences among IFs, but no marked difference in flavors was found according to CATA and physicochemical analysis. Additionally, no unpleasant sensory descriptors were noted. This shows that the minimally processed route leads to IFs that could fit well within the market from a sensory point of view.

Factors affecting scum formation and the use of electronic nose to identify fundamental odor properties in urban estuaries

Factors affecting scum formation and the use of electronic nose to identify fundamental odor properties in urban estuaries

Is the perception of odour pleasantness shared across cultures and ecological conditions? Evidence from Amazonia, East Africa, New Guinea, Malaysia and Poland.

What makes an odour pleasant or unpleasant? The inherent properties of the constituent chemical compounds, or the nose of the beholder, driven by idiosyncratic differences and culture-specific learning? Here, 582 individuals, including Tanzanian Hadza hunter-gatherers, Amazonian Tsimane' horticulturalists, Yali from the Papuan highlands and two industrialized populations (Poles, Malaysians), rated the pleasantness of 15 odour samples. We find considerable similarities in odour assessments across cultures, but our data do not fully support a claim regarding the universality of smell preferences. Despite cross-cultural similarities in olfactory assessments, probably driven by odour properties, we suggest that odour availability in ecological and cultural niches bears an undeniable effect on human odour preferences.

Comparative study on nutraceutical and sensorial characteristics of saffron (Crocus sativus L.) cultivated in Iran, Spain, and Türkiye.

Quality properties of 14 saffron samples from Iran, Spain, and Türkiye were compared. Significant differences were observed between anthocyanins, volatile compounds, fatty acids, total phenolic content, and antioxidant activity of saffron samples (P < 0.05). Besides, significant differences in color parameters were observed. Moreover, a total of 13 volatile compounds were identified in the saffron samples using. headspace-solid-phase microextraction-gas chromatography-mass spectrometry, safranal and α-isophorone being the two predominant aroma compounds. Regarding fatty acids, significant differences were seen in the fatty acid profiles of saffron samples (P < 0.05), while linoleic acid was the most concentrated fatty acid. In terms of sensory properties, different concentrations of safranal, α-isophorone and 4-ketoisophorone may lead to significant differences in the odor and taste attributes of saffron samples (P < 0.05). Changes in corm origin along with climate and agricultural conditions may affect the quality characteristics of saffron cultivated in different geographical areas to a significant degree. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of Lactobacillus plantarum and flavourzyme on protein degradation and flavor development in grass carp during fermentation

This study examined the effect of Flavourzyme and Lactobacillus plantarum (L. plantarum) on protein degradation and flavor development during grass carp fermentation. The control groups comprised natural fermentation and fermentation with L. plantarum. Compared with the two control samples, those exposed to combined Flavourzyme and L. plantarum fermentation exhibited lower moisture content and enhanced protein hydrolysis, which accelerated the production of water-soluble taste substances (trichloroacetic acid-soluble peptides and free amino acids). The electronic tongue and electronic nose results indicated that the grass carp subjected to combined fermentation way displayed a more intense umami taste and aroma. Moreover, the sensory evaluation results confirmed that the combined fermentation method significantly improved the taste and odor attributes of fermented grass carp. In conclusion, combined fermentation with Flavourzyme and L. plantarum may effectively reduce fermentation time and enhance the flavor of fermented grass carp products.

UV-C-induced changes in a white wine: Evaluating the protective power of hydrolysable tannins and SO&lt;sub&gt;2&lt;/sub&gt;

UV‑C treatment is a non-thermal technology that could be used for the microbiological stabilisation of must and wine. However, light - in this case UV‑C light - has an impact on wine. UV‑C is a high-energy light source and can promote photo-induced oxidation reactions. The formation of reactive oxygen species during the UV-C treatment of wine can be prevented via supplementation with antioxidants. These have the ability to neutralise reactive oxygen species or directly interact with the products of photo-induced oxidation reactions. This study investigates the impact of different UV‑C doses on the chemical and sensory characteristics of Chardonnay wine and examines the protective effect of two antioxidants: sulphur dioxide (SO2) and hydrolysable tannins. A sensory evaluation revealed that UV‑C doses higher than 1 kJ/l increased the colour intensity and the oxidised and burnt odour attributes of the wine. The peach odour attribute decreased with UV‑C treatment. On a chemical level, increasing UV‑C doses promoted the formation of compounds such as acetaldehyde and 2‑aminoacetophenone (2‑AAP), while causing the degradation of C13‑norisoprenoids, higher alcohols, monoterpenes and esters. Contrary to expectations, SO2 did not act as an antioxidant when wine was treated with UV-C. It intensified the burnt odour attribute and did not mitigate the intensity of the oxidised odour attribute, which can be explained by the formation of acetaldehyde. However, hydrolysable tannins acted as antioxidants when combined with UV‑C treatment, effectively mitigating the formation of 2‑AAP and acetaldehyde, while preventing the wine from becoming oxidised.

Improved Quantification of Geosmin and 2-Methylisoborneol in Farmed Fish Using Stable Isotope Dilution Gas Chromatography-Mass Spectrometry.

A requisite to improving the taste and odor attributes of farmed fish is the availability of accurate and practical analytical methods to quantify 2-methylisoborneol (MIB) and geosmin (GSM). Solid-phase microextraction (SPME) enables reliable measurement of nanogram per liter quantities of MIB and GSM in water. In contrast, direct headspace (HS)-SPME of biological matrices with variable proximate compositions can increase bias and uncertainty in off-flavor determinations. Analytical recovery plays a crucial role in the accurate determination of MIB and GSM in fish, and this study investigates strategies to maximize and account for this recovery factor. MIB and GSM values in off-flavor catfish and trout were measured using direct HS-SPME and distillation as sample preparation techniques. Trout samples prepared by distillation yielded 10-fold higher GSM recoveries than those from direct HS-SPME (31% versus 3%). A stable isotope dilution method (SIDM) was implemented by routinely spiking samples with known quantities of deuterium-labeled MIB and GSM, allowing for the correction of sample-to-sample recovery deviations. SIDM-determined GSM values generated recoveries of 106 and 95% for direct HS-SPME and distilled trout, respectively. Aspects of the strategies and techniques presented can be incorporated into existing analytical methods to improve the accuracy and sample throughput. Particularly, routine inclusion of SIDM in the evaluation of MIB and GSM can facilitate identification of reliable practices to control off-flavors in aquaculture.

Physical properties of odorants affect behavior of trained detection dogs during close-quarters searches

Trained detection dogs have a unique ability to find the sources of target odors in complex fluid environments. How dogs derive information about the source of an odor from an odor plume comprised of odorants with different physical properties, such as diffusivity, is currently unknown. Two volatile chemicals associated with explosive detection, ammonia (NH3, derived from ammonium nitrate-based explosives) and 2-ethyl-1-hexanol (2E1H, associated with composition C4 plastic explosives) were used to ascertain the effects of the physical properties of odorants on the search behavior and motion of trained dogs. NH3 has a diffusivity 3.6 times that of 2E1H. Fourteen civilian detection dogs were recruited to train on each target odorant using controlled odor mimic permeation systems as training aids over 6 weeks and then tested in a controlled-environment search trial where behavior, motion, and search success were analyzed. Our results indicate the target-odorant influences search motion and time spent in the stages of searching, with dogs spending more time in larger areas while localizing NH3. This aligns with the greater diffusivity of NH3 driving diffusion-dominated odor transport when dogs are close to the odor source in contrast to the advection-driven transport of 2E1H at the same distances.

Data-centric artificial olfactory system based on the eigengraph

Recent studies of electronic nose system tend to waste significant amount of important data in odor identification. Until now, the sensitivity-oriented data composition has made it difficult to discover meaningful data to apply artificial intelligence in terms of in-depth analysis for odor attributes specifying the identities of gas molecules, ultimately resulting in hindering the advancement of the artificial olfactory technology. Here, we realize a data-centric approach to implement standardized artificial olfactory systems inspired by human olfactory mechanisms by formally defining and utilizing the concept of Eigengraph in electrochemisty. The implicit odor attributes of the eigengraphs were mathematically substantialized as the Fourier transform-based Mel-Frequency Cepstral Coefficient feature vectors. Their effectiveness and applicability in deep learning processes for gas classification have been clearly demonstrated through experiments on complex mixed gases and automobile exhaust gases. We suggest that our findings can be widely applied as source technologies to develop standardized artificial olfactory systems.

The role of the mediodorsal thalamus in chemosensory preference and consummatory behavior in rats.

Experience plays a pivotal role in determining our food preferences. Consuming food generates odor-taste associations that shape our perceptual judgements of chemosensory stimuli, such as their intensity, familiarity, and pleasantness. The process of making consummatory choices relies on a network of brain regions to integrate and process chemosensory information. The mediodorsal thalamus is a higher-order thalamic nucleus involved in many experience-dependent chemosensory behaviors, including olfactory attention, odor discrimination, and the hedonic perception of flavors. Recent research has shown that neurons in the mediodorsal thalamus represent the sensory and affective properties of experienced odors, tastes, and odor-taste mixtures. However, its role in guiding consummatory choices remains unclear. To investigate the influence of the mediodorsal thalamus in the consummatory choice for experienced odors, tastes, and odor-taste mixtures, we pharmacologically inactivated the mediodorsal thalamus during 2-bottle brief-access tasks. We found that inactivation altered the preference for specific odor-taste mixtures, significantly reduced consumption of the preferred taste and increased within-trial sampling of both chemosensory stimulus options. Our results show that the mediodorsal thalamus plays a crucial role in consummatory decisions related to chemosensory preference and attention.

Effect of Low-calorie Sweeteners on Sensory, Physicochemical, and Quality Attributes of Goldenberry (Physalis peruviana L.) Juice

Background: The goldenberry is a fruit that grows in the Andean valleys of Ecuador and Peru. The goldenberry has a high nutritional value, thanks to the presence of ascorbic acid, carotenoids, and total phenols. Also, this fruit has shown the ability to attenuate hepatorenal injuries, antidiabetic and antihypertensive effects, and hepatoprotective effects. Objective: The work aimed to take advantage of the nutritional and medicinal properties of the goldenberry (Physalis peruviana L.) by developing a juice substituting sucrose for low-calorie sweeteners. Also, this study evaluated the effect of these sweeteners on sensory, physicochemical, and quality of juice attributes. Methods: Different formulations were tested, varying the percentage of pulp, sweeteners (sucrose, sucralose, and acesulfame K), and stabilizer (xanthan gum). The formulations were subjected to sensory analysis using 48 semi-trained tasters. The acidity, pH, soluble solids, and density were analyzed using the methodology described in Ecuadorian standards. In addition, the nutritional and microbiological quality was analyzed, and a shelf-life study was carried out under normal and accelerated conditions. Results: The best formulation was elaborated with 30% goldenberry pulp, 0.016% acesulfame K, 0.0054% sucralose, and 0.1% xanthan gum. The best formulation showed 0.3% of protein, 0.3% of ash, 4% of carbohydrates, and 35 mg/100 g of vitamin C. Consumption of 500 ml of the beverage provided 17 Kcal. It can be preserved for 2.5, 1.6, and 0.8 months at 8, 20, and 35ºC storage temperatures, respectively. Conclusion: The best formulation scored better in odor and general acceptability attributes. Also, this formulation showed a synergistic effect between the fruit components and the low-calorie sweeteners, generating an effect that intensifies the sensory fruity aroma.

Pengaruh Suhu Pengeringan terhadap Karakteristik Kimia, Fisik dan Sensoris Dendeng Ikan Lemuru (Sardinella lemuru)

&#x0D; &#x0D; &#x0D; Lemuru fish (Sardinella lemuru) is susceptible to spoilage, especially when its abundance is high, requiring processing. One form of processing is to turn it into lemuru fish jerky.Tthe production of lemuru fish jerky still faces challenges in achieving satisfactory product quality due to the varying meat characteristics of different fish types, necessitating diverse drying temperatures. The aim of this research was to investigate the effect of drying temperature on the chemical, physical, and sensory properties of lemuru fish jerky and to obtain the optimal drying temperature for producing jerky with the best quality. The experiment followed a Randomized block design with five treatment levels: 50°C, 55°C, 60°C, 65°C, and 70°C. Drying was carried out until the moisture content reached a maximum of 12%. All treatments were repeated three times, resulting in 15 experimental units. The data were analyzed using analysis of variance, and treatments showing significant effects were further tested using Duncan's Multiple Range Test. The results showed that drying temperature significantly influenced (P&lt;0,05) the moisture content, fat content, protein content, ash content, hardness, water activity (Aw), color values (L, a*, and b*) and sensory characteristics (color, odor, texture, and overall acceptance) of lemuru fish jerky. Drying at 65°C for 7 hours resulted in lemuru fish jerky with the best chemical, physical, and sensory characteristics, including moisture content of 11.51%, fat content of 6,01%, protein content of 49,61%, ash content of 11,04%, insoluble ash content of 0.07%, Aw value of 0.55, hardness value of 69,25 N, L value of 26.50, a* value of 5.00, b* value of 4.87, and preferred sensory properties of color, odor, texture, and overall acceptance by the panelists.&#x0D; &#x0D; &#x0D;