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Correction: Chemical Senses, Volume 46, 2021, bjab050, https://doi.org/10.1093/chemse/bjab050 Published: 08 December 2021 Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments, such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation, and initial results of a multilingual, international questionnaire to assess self-reported quantity and quality of perception in 3 distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, and 8 others, aged 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste, and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change +/- 100) revealed a mean reduction of smell (-79.7 +/- 28.7, mean +/- standard deviation), taste (-69.0 +/- 32.6), and chemesthetic (-37.3 +/- 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell but also affects taste and chemesthesis.The multimodal impact of COVID-19 and the lack of perceived nasal obstruction suggest that severe acute respiratory syndrome coronavirus strain 2 (SARS-CoV-2) infection may disrupt sensory-neural mechanisms.

The aim of this study was to investigate whether the use of smoked ingredients could enhance either salty or umami taste, whether any enhancement was due to taste-active or taste-enhancing compounds, and whether smoky aroma induced taste enhancement. A trained sensory panel (n=12) performed three-Alternative Forced Choice (3-AFC) discrimination tests with nose clips on to assess taste-active and taste-enhancing compounds in smoked water. The first set of 3-AFC discrimination tests investigated whether there were any tastes, particularly salty or umami, in water with addition of 1% of a commercial smoked water. The second set of 3-AFC tests investigated whether the smoked water contained umami-enhancing compounds when mixed with various concentrations of MSG and /or ribonucleotides in water. Set 3 was similar but was carried out in a model chicken soup containing MSG with or without ribonucleotides. Our data show that the addition of smoked water can increase the umami taste in aqueous solutions, but this is masked in more complex matrices. This means we can investigate odour-induced taste enhancement of smoked water, in the knowledge that there will be minimal contribution to the umami and salty taste from the smoked water.

Diketopiperazines are cyclic dipeptides which impart bitterness and metallic flavour. They have previously been reported at subthreshold levels in raw cheese, but not studied in cooked cheese. Four diketopiperazines (cyclo-Pro-Pro, cyclo-Val-Pro, cyclo-Ala-Pro and cyclo-Leu-Pro) were detected in seven cooked cheeses (parmesan, mozzarella, and five different cheddars). Diketopiperazines were present in substantially higher concentrations in the cooked cheeses than their raw counterparts and were above bitter and metallic thresholds in some cooked samples. Diketopiperazine formation during cooking was higher in mature cheeses than in young cheeses, suggesting that aging cheeses produces precursors to diketopiperazine formation in the raw cheese.

Among those many individuals who suffer from a reduced odor sensitivity (hyposmia/anosmia) some individuals also experience disorders that lead to odor distortion, such as parosmia (i.e., distorted odor with a known source), or odor phantoms (i.e., odor sensation without an odor source). We surveyed a large population with at least one olfactory disorder (N = 2031) and found that odor distortions were common (46%), with respondents reporting either parosmia (19%), phantosmia (11%), or both (16%). In comparison to respondents with hyposmia or anosmia, respondents with parosmia were more likely to be female, young, and suffering from post-viral olfactory loss (p < 0.001), while respondents with phantosmia were more likely to be middle-aged (p < 0.01) and experiencing symptoms caused by head trauma (p < 0.01). In addition, parosmia, compared to phantosmia or anosmia/hyposmia, was most prevalent 3 months to a year after olfactory symptom onset (p < 0.001), which coincides with the timeline of physiological recovery. Finally, we observed that the frequency and duration of distortions negatively affects quality of life, with parosmia showing a higher range of severity than phantosmia (p < 0.001). Previous research often grouped these distortions together, but our results show that they have distinct patterns of demographics, medical history, and loss in quality of life.

(E)-β-Damascenone (bDam) is one of the most important aroma compounds in foods and in both regular and alcohol-free beers. In the present study, the effect of the curing temperature during kilning on the concentration of bDam in malt was monitored, as well as during mashing and wort boiling. Two different varieties of malt (spring and winter) were compared. The results showed different trends during malt kilning, with an increase in the levels of the aroma compound over time at 78 and 90°C. During mashing and wort boiling, bDam was formed following different trends, this attributed to a balance between formation and evaporation. Moreover, malts and worts from winter barley contained more bDam than spring barley. Further research is required in order to identify and monitor the precursors of this potent aroma compound.

Since the onset of the COVID-19 pandemic, incidences of loss of smell and taste have increased substantially and, whereas many of these recover within a few weeks, in about 5% of all cases of COVID-19, olfactory dysfunction persists for many months or years. During the recovery process, many experience parosmia, which is a condition in which everyday aromas become distorted and usually evoke a sense of disgust. Previous work has shown that a set of highly potent odorants in coffee can trigger these distortions. They fall into clusters of thiols, disulphides and pyrazines, and many (but not all) of these compounds are products of the Maillard reaction. In this work, we investigated another Maillard system and asked whether any of the Maillard-derived trigger molecules from coffee were also reported to be triggers in grilled chicken. GC-olfactometry was carried out by four participants and one non-parosmic expert to assess all the odour-active compounds in grilled chicken. Results revealed that indeed six triggers were found in common with coffee – all derived from the Maillard reaction. We postulate that the same few compounds may be responsible for distortions in many roasted, grilled and fried foods, and recommend that those suffering from parosmia avoid highly cooked foods.

This is a correction notice for article bjaa041 (DOI: https:// doi.org/10.1093/chemse/bjaa041), published 20 June 2020. An incorrect version of the caption to Figure 5 was mistakenly included in the published paper. An updated version is given below. Neither the data nor the paper's conclusions were affected by this correction. The authors sincerely apologize for the error. (A) Correlations between the 3 principal components with respect to changes in 3 chemosensory modalities (i.e., taste, smell, and chemesthesis). Shades of gray indicate positive correlation, whereas shades of red indicate negative correlations. White denotes no correlation. (B) Clusters of participants identified by k-means clustering. The scatterplot shows each participant's loading on dimension 1 (degree of smell and taste loss, PC1 on x-Axis) and dimension 2 (degree of chemesthesis loss, PC2 on y-Axis). Based on the centroid of each cluster, participants in cluster 1 (blue, N = 1767; top left) are generally characterized by significant smell, taste and chemesthesis loss. Participants in cluster 2 (orange, N = 1724; bottom center) are generally characterized by ratings that reflect smell/taste loss with preserved chemesthesis. Loadings for participants in cluster 3 (green, N = 548; right side) are generally characterized by reduced smell and taste loss, and preserved chemesthesis.

Alcohol-free beers (AFB) brewed by cold-contact fermentation exhibit a flavor reminiscent of wort which affects consumer acceptability. The aims of this study were to identify the odor-active compounds in AFB and elucidate the contribution of these to the overall aroma and worty character of the beer. Using a sensomics approach, 27 odor-active aroma compounds were identified and quantitated using GC-MS. The most odor-active compound was methional (boiled potato-like aroma), followed by 3-methylbutanal (cocoa-like), (E)-β-damascenone (apple, jam-like), 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone (curry, spicy-like), and phenylacetaldehyde (floral, honey-like). The important contribution of these flavor compounds to the worty and honey aroma of AFB was determined by sensory assessment of the recombinate in a beer-like matrix with omission tests. The role of 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone in AFB aroma was reported for the first time. The outcomes from this study are of relevance for the brewing industry to design strategies for the reduction of the wortiness of AFB.

BACKGROUND\ud Phospholipids are an important precursor for the generation of carbonyl compounds which play a significant role in the characteristic aroma of deep-fat fried foods. \ud RESULTS\ud Phospholipids extracted from hen egg yolks were added into sunflower oil (2.0 g/kg) and heated with or without chicken meat at 160 °C for 10 min, and then dynamic headspace extraction and GC-MS were used to extract and analyze the volatiles. The results showed that the characteristic deep-fat frying odorants, such as (E,E)-2,4-decadienal, (E,Z)-2,4-decadienal, as well as 1-octen-3-one, (E)-2-nonenal, octanal, methional, dimethyl disulfide and alkylpyrazines had increased by 3-65 times in the sunflower oil with added phospholipids, and increased up to 6 times in chicken meat which had been treated with phospholipids prior to heating. \ud CONCLUSION\ud There is potential for the food industry to use low levels of phospholipids, particularly egg yolk phospholipids, to increase deep-fat frying odorants in a wide range of deep fried products.

Lipids, particularly phospholipids, are known to play a significant role in the characteristic aroma of the different meat species. Both neutral lipids and phospholipids were extracted from egg yolk and added to minced chicken (1% w/w) prior to cooking in water at 100 °C for 20 min. Sensory analysis of the broths showed that the addition of phospholipids significantly increased the chicken meat aroma whereas the addition of neutral lipids did not. GC-MS analysis showed a significant increase in most of the lipid-derived volatile components when the phospholipids were added, especially 2,4-decadienal which is a characteristic odour impact compound in chicken. There were very few significant changes in the volatile profile when the neutral lipids were added. These data provide direct evidence that the addition of phospholipids can enhance chicken meat aroma, and addition of egg yolk phospholipids could be applied to improve chicken meat aroma.

In light of a recent update in EU regulations governing levels of acrylamide in foodstuffs, further understanding of the role of different precursors is fundamental to extending mitigation strategies into a wider product range. Kinetic modelling was used to investigate the role of maltose in the formation of acrylamide during the finish-frying of french fries. The maltose concentration of raw white potato strips was systematically increased to observe the effect of this reducing disaccharide on acrylamide formation. A mathematical model, incorporating glucose, fructose and maltose and based on known Maillard reaction pathways, was developed which showed that acrylamide formation from maltose only contributed

Detection thresholds are used routinely to determine the odour-active compounds in foods. The composition of a food matrix, such as hydrophobicity or solids content, has an impact on the release of flavour compounds, and thus on thresholds. In the case of beer, thresholds determined in alcoholic beer may not be the same for alcohol-free beer (AFB). Therefore, the aim of this study was to determine detection thresholds for aroma compounds typically found in beer within a model AFB. The model was designed to match the sugar concentration and pH of an AFB brewed by a cold contact process. Thresholds were measured using a 3-AFC procedure and calculated using either Best Estimate Threshold (BET) method or by logistic regression. Moreover, an algorithm for the removal of false positives was applied to adjust the assessors’ raw responses. Retronasal thresholds were generally lower than orthonasal. Those calculated by BET were significantly higher (p < 0.05) than those from logistic regression, and removal of false positives also produced significantly higher thresholds than those from raw data. The use of logistic regression has the advantage of providing the mathematical model describing the behaviour of the group. The results from this study can be used to better understand the role of flavour compounds in AFB and the effect of the calculation method to prevent under- or overestimated results.

The popularity of smoked foodstuffs such as sauces, marinades and rubs is on the rise. However, during the traditional smoking process, in addition to the desirable smoky aroma compounds, harmful polycyclic aromatic hydrocarbons (PAHs) are also generated. In this work, a selective filter has been developed which reduces PAH concentrations in a smoke by up to 90%, whilst maintaining a desirable smoky flavor. Preliminary studies using a cocktail of 12 PAHs stirred with a zeolite showed the potential for this zeolite to selectively remove PAHs from a simple solution. However pre-treatment of the smoke prior to application removed the PAHs more efficiently and is more widely applicable to a range of food ingredients. Whilst volatile analysis showed that there was a concomitant reduction in the concentration of the smoky compounds such as 2-methoxyphenol (guaiacol), 2-methylphenol (m-cresol) and the isoeugenols, qualitative descriptive analysis by a sensory panel showed that the difference in perception of flavour was minimal.

The mucoadhesion between polymeric substances and mucosal membranes, widely exploited in the pharmaceutics industry to prolong drug residence, has been investigated as a means of retaining taste or aroma molecules in the oral cavity. This study shows that the mucoadhesive properties of carboxymethyl cellulose, a commonly used polysaccharide in the food and pharmaceutics industry, can modify retention, release and perception of sodium over time. A three-part study was designed coupling in vitro retention using ex vivo porcine tongue, sensory perception with a trained panel and in vivo retention of sodium ions in human volunteers. The findings suggest that although salt perception is stunted in samples containing a random coil, ionic, mucoadhesive thickener, the retention of sodium ions in the mouth is prolonged due to the mucoadhesive nature of the polysaccharide. Not only has this study-investigated mucoadhesion of liquid formulations in the oral cavity but it is also the first to link the mucoadhesive nature of a commonly used polysaccharide to the organoleptic properties of a food.

The role of mucoadhesion in the perception and sensory characterisation of food products is becoming more apparent. Traditionally, mucoadhesives are used to enhance drug permeability and retention at mucosal membranes in the body, by adherence to a mucosal membrane formed through various interactions between the mucoadhesive and proteins present in the mucosa. Many polysaccharides used in the food industry as thickeners, emulsifiers, stabilisers and fat replacers also have mucoadhesive properties, and are commonly used in the pharmaceutical industry in drug formulations. More recently, there has been an increasing interest in utilising these polysaccharides as mucoadhesives to modulate the organoleptic properties of food. This review reflects on the recent developments in mucoadhesion and the limited research into the impact of mucoadhesion when designing food formulations and modifying the organoleptic properties of food. It will also outline the areas of food science that could benefit from an understanding of mucoadhesion, mainly focusing on developing an understanding of how mucoadhesion may explain results found from sensory studies involving polysaccharides. Furthermore, possible negative impacts of mucoadhesion in foodstuff will be explored. An overview of methods for the measurement of mucoadhesion is also provided. An understanding of the mucoadhesive nature of polysaccharides may be useful to the food industry with regard to new product design.

Jackfruit seeds are an under-utilized waste in many tropical countries. In this work, we demonstrate the potential of roasted jackfruit seeds to develop chocolate aroma. Twenty-seven different roasted jackfruit seed flours were produced from local jackfruit by acidifying or fermenting the seeds prior to drying, and roasting under different time/temperature combinations. The chocolate aroma of groups of four flours were ranked by a sensory panel (n=162) and response surface methodology was used to identify optimum conditions. The results indicated a significant and positive influence of fermentation and acidification on the production of chocolate aroma. SPME/GC-MS of the flours showed that important aroma compounds such as 2,3-diethyl-5-methylpyrazine and 2-phenylethyl acetate were substantially higher in the fermented product, and that the more severe roasting conditions produced 2-3 times more 2,3-diethyl-5-methylpyrazine, but less 3-methylbutanal. Moisture, aw, pH, luminosity and color were also monitored to ensure that these properties were similar to cocoa powder or cocoa substitutes.

Milk powder is an important ingredient in the confectionary industry but its variable nature has consequences for the quality of the final confectionary product. This paper demonstrates that skim milk powders (SMP) produced using different (but typical) manufacturing processes, when used as ingredients in the manufacture of model white chocolates, had a significant impact on the sensory and volatile profiles of the chocolate. SMP was produced from raw bovine milk using either low or high heat treatment, and a model white chocolate was prepared from each SMP. A directional discrimination test with naïve panellists showed that the chocolate prepared from the high heat SMP had more caramel/fudge character (p

For modeling and predicting the formation of acrylamide in real food systems, it is not only important to understand the underlying chemistry, but also the complex effects of heat and moisture transfer which means that in French fries, for example, most of the acrylamide is formed on the edges and corners of the fry. In this paper, simple approximations have been employed to build a mathematical model that approximates the heat and mass transport phenomena in three dimensions. It successfully predicts the concentration of acrylamide and its precursors at different positions in the ‘fry’.