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During the process of caramelization, volatile and non-volatile flavor and color are generated via the degradation of carbohydrates. This research investigated the effect of the types and concentrations of salts including NaCl and KCl on the generation of volatile aromas and color during caramelization. The solid phase microextraction-gas chromatograph-mass spectrometry (SPME-GC-MS) was used to measure the volatile compounds generated in caramelization. The results demonstrated that increasing content of salt (NaCl or KCl) could significantly improve (P

Dee are a unique and rapidly growing part of the global snack food market and are recognised as having distinct sensory properties (taste and texture). In this study, the development of important volatile aroma compounds over storage was evaluated and their chemical origin explained. Sweet potatoes were batch fried in high oleic sunflower oil (HOSO) and subjected to accelerated shelf life testing. Headspace volatiles were analysed using SPME GC-MS and correlated with sensory perception. All the components (sweet potatoes, oil and β-carotene) showed significant degradation after 3 weeks of storage at accelerated conditions (equivalent to 12 weeks in real-time at 25 °C). Marker volatiles associated with lipid oxidation such as hexanal, octanal, pentanal were identified, in addition to norisoprenoids from β-carotene degradation such as β-ionon, 5,6-epoxy-β-ionone, dihydroactinidiolide (DHA) and β-cyclocitral. The most prominent marker of lipid oxidation (hexanal) rapidly increased at week 1, whereas the carotene degradation makers did not rapidly increase until week 3 suggesting a delayed response. The frying temperature during the batch frying process of SPC was also shown to play a significant role in the sensory perception of the product over the shelf life. Overall, the results suggest that tight control of process variables and raw material design may enable extended shelf life and potentially enhanced health credentials for the product. These findings are unique to SPC, but also of value to the wider food industry., Lipid oxidation markers, degradation markers of β-carotene and changes in sensory properties were tracked in fried sliced sweet potatoes over shelf life and under different frying conditions.

Purpose Insulin, in typical use, undergoes multiple changes in temperature; from refrigerator, to room temperature, to body temperature. Although long-term storage temperature has been well-studied, the short term changes to insulin are yet to be determined. Insulin detemir (IDet) is a clinically available, slow-acting, synthetic analogue characterised by the conjugation of a C14 fatty acid. The function of this modification is to cause the insulin to form multi-hexameric species, thus retarding the pharmacokinetic rate of action. In this investigation, the temperature dependence properties of this synthetic analogue is probed, as well as expiration. Methods Dynamic light scattering (DLS) and viscometry were employed to assess the effect of temperature upon IDet. Mass spectrometry was also used to probe the impact of shelf-life and the presence of certain excipients. Results IDet was compared with eight other insulins, including human recombinant, three fast-acting analogues and two other slow-acting analogues. Of all nine insulins, IDet was the only analogue to show temperature dependent behaviour, between 20 °C and 37 °C, when probed with non-invasive backscatter dynamic light scattering. Upon further investigation, IDet observed significant changes in size related to temperature, direction of temperature (heated/cooled) and expiration with cross-correlation observed amongst all 4 parameters. Conclusions These findings are critical to our understanding of the behaviour of this particular clinically relevant drug, as it will allow the development of future generations of peptide-based therapies with greater clinical efficacy.

Inorganic-phosphate, potassium, and magnesium are key-minerals required for yeast growth, metabolism, and survival, the present work investigated its impact in yeast-flavour formation using a multi-factor experimental design, which was used to generate a range of phosphorous-potassium-magnesium resulting in a 28-point D-optimal design. Samples were evaluated using HPLC (ethanol), GC-MS (aroma), and CountStar (total yeast cell). Results revealed that yeast requires a minimal amount of inorganic-phosphate, potassium, and magnesium (250, 500, and 70 mg/L, respectively) to support yeast-growth and ethanol/flavour formation. Inorganic-phosphate was important for fatty acid esters formation/short chain fatty acid (SCFA) reduction. Potassium was important in the formation of acetate esters/higher alcohols. Magnesium was the most important inorganic element for ester formation/SCFA reduction; furthermore, ethanol production is magnesium-dependent. In conclusion, inorganic phosphate, potassium and magnesium play an important role in yeast-growth, esters and higher alcohols formation; and SCFA reduction. Ethanol formation is Mg-dependent.

Coffee aroma is critical for consumer liking and enables price differentiation of coffee. This study applied hyperspectral imaging (1000–2500 nm) to predict volatile compounds in single roasted coffee beans, as measured by Solid Phase Micro Extraction-Gas Chromatography-Mass Spectrometry and Gas Chromatography-Olfactometry. Partial least square (PLS) regression models were built for individual volatile compounds and chemical classes. Selected key aroma compounds were predicted well enough to allow rapid screening (R2 greater than 0.7, Ratio to Performance Deviation (RPD) greater than 1.5), and improved predictions were achieved for classes of compounds - e.g. aldehydes and pyrazines (R2 ∼ 0.8, RPD ∼ 1.9). To demonstrate the approach, beans were successfully segregated by HSI into prototype batches with different levels of pyrazines (smoky) or aldehydes (sweet). This is industrially relevant as it will provide new rapid tools for quality evaluation, opportunities to understand and minimise heterogeneity during production and roasting and ultimately provide the tools to define and achieve new coffee flavour profiles.

Rapid volatile detection methods for seed vigour rely heavily on artificial ageing (AA), however the comparability of volatile organic compounds (VOCs) to natural ageing (NA) and practicability of the detection models were not well known. In this study, VOCs between AA and NA sweet corn seeds were compared and Partial Least Squares Regression (PLS-R) models were constructed based on AA to predict the seed vigour of NA. A total of 33 VOCs were identified, among which aldehydes showed the highest consistency between NA and AA. Furthermore, a AS-PLS-R model with variable importance in projection (VIP > 1) and Pearson Correlation Coefficient (r > 0.9) algorithms, which was built on 3 volatile markers: benzaldehyde monomer, n-nonanal, 1-butanol monomer, achieved the best performance (R2p of 0.901 and RMSEP of 0.050). Therefore, coupling Gas Chromatography- Ion Mobility Spectrometry (GC-IMS) with chemometrics can be an effective way to monitor and predict stored seeds vigour.

This study aims to understand possible effects of flavour compounds on the structure and conformation of endogenous proteins. Using methyl anthranilate (a grape flavour compound added to drinks, confectionery, and vape-liquids) and bovine serum albumin (BSA, a model serum protein) we designed experimental investigations using analytical ultracentrifugation, size exclusion chromatography small angle X-ray scattering, and fluorescence spectroscopy to reveal that methyl anthranilate spontaneously binds to BSA (ΔG°, ca. -21 KJ mol

Use of oral nutritional supplements (ONS) in undernourished patients has proven clinical benefits, but this can be hampered by low adherence due to poor experience of palatability. Many patients, particularly older patients, experience hyposalivation which can cause taste changes and reduce the enjoyment of foods. The aim of this study was to investigate differences in the temporal consumption experience (comprising sensory perception, in-mouth aroma release and subjective appetite) of a clinically relevant portion of ONS, for groups differing in saliva flow rates (SFR). The SFR (mL/min) of thirty healthy individuals was measured on three occasions. This data was used to categorise individuals into three groups using quartile analysis: low flow (LF) (0.3–0.6 mL/min, n = 5), medium flow (MF) (0.7–1.2 mL/min, n = 16) and high flow (HF) (1.3–1.8 mL/min, n = 9). Over the consumption of eight 15 mL sips of ONS, individuals rated their sensory perception and subjective appetite perception using line scales. Additionally, in-mouth aroma release was measured for each sip, using atmospheric pressure chemical ionisation (APCI). Compared with the MF and HF group, the LF group reported a significantly greater increase of mouth-drying over increased sips (p = 0.02). The LF group also experienced significantly higher aftertaste perception (p, Highlights • A full portion of ONS was evaluated by three groups differing in saliva flow rates. • A sensory profiling method captured perceptual differences over repeated sips. • Mouth-drying built up most significantly for the low saliva flow group. • Intensity of aftertaste and aroma release was highest in the low saliva flow group. • Sensorial intensity of ONS may be associated with greater feelings of satiation.

The aroma stability of fresh coffee brew was investigated during storage over 60 minutes, there was a substantial reduction in available 2-furfurylthiol (2-FFT) (84%), methanethiol (72%), 3-methyl-1H-pyrole (68%) and an increase of 2-pentylfuran (65%). It is proposed that 2-FFT was reduced through reversible chemical binding and irreversible losses. Bound 2-FFT was released after cysteine addition, thereby demonstrating that a reversible binding reaction was the dominant mechanism of 2-FFT loss in natural coffee brew. The reduction in available 2-FFT was investigated at different pH and temperatures. At high pH, the reversible binding of 2-FFT was shown to protect 2-FFT from irreversible losses, while irreversible losses led to the reduction of total 2-FFT at low pH. A model reaction system was developed and a potential conjugate, hydroxyhydroquinone, was reacted with 2-FFT. Hydroxyhydroquinone also showed 2-FFT was released after cysteine addition at high pH.

© 2018 Elsevier Ltd This study attempted to improve Robusta sensory properties by modifying the beans chemical composition. Building on our previous work, which modified bean pH through acid pre-treatment, a model system was developed where, sugar solutions (glucose, fructose, sucrose) were used to pre-treat Robusta coffee beans with the aim to modify the concentration/availability/location of these aroma precursors. Beans were then dried to equal water activity, subjected to equal roast intensity and ground to comparable particle size distributions. The treatment significantly impacted aroma generation during roasting leading to an altered level of pyrazines, furans, ketones, organic acid and heterocyclic nitrogen-containing compounds (p < 0.05). The optimum treatment was 15 g/100 g fructose. 80% treated Robusta could be blended with Arabica in coffee brew without significant aroma differences being perceived when compared to 100% Arabica brew. Furthermore the aroma of the fructose treated Robusta was more stable than Arabica over six weeks accelerated shelflife storage.

Undernutrition is prevalent in the older adult population. Oral nutritional supplements (ONS) are a clinically effective nutritional intervention, however, patient acceptance of ONS can be limited by their palatability. While sensory attributes such as sweetness and mouthfeel have been investigated, the contribution made by aroma to the perceived flavour of ONS has not been studied. Firstly, this research aimed to identify the aroma active compounds within a commonly prescribed ONS using estimated odour activity values (OAV) and gas chromatography olfactometry mass spectrometry (GC-O-MS). Secondly, age related differences in olfactory detection were explored. Eight aroma active compounds were identified within the ONS, including diacetyl (sweet), isoamyl acetate (banana), dimethyl trisulfide (sulfur) and methanethiol (sulfur). When compared with younger adults (n = 24, 18–44 years), older adults (n = 24, 62–80 years) had higher detection thresholds for all aroma compounds and this was significant for isoamyl acetate (sweet, fruity) and methanethiol (sulfur) (p = 0.01 and p = 0.03, respectively). Thus, a decline in olfactory sensitivity was present in the older subjects included in the study, and this reduced detection sensitivity was aroma specific. Thus, older adults’ flavour perception of ONS likely depends on the combined effect of product factors (the aroma profile) along with age related consumer factors (the degree of impairment in perception). This is a fundamental study which will aid future research into how the aroma profile, and associated age related impairments in perception, shape the global perception of ONS for nutritionally at risk older individuals.

Due to unique characteristics, umami substances have gained much attention in the food industry during the past decade as potential replacers to sodium or fat to increase food palatability. Umami is not only known to increase appetite, but also to increase satiety, and hence could be used to control food intake. Therefore, it is important to understand the mechanism(s) involved in umami taste perception. This review discusses current knowledge of the mechanism(s) of umami perception from receptor level to human brain imaging. New findings regarding the molecular mechanisms for detecting umami tastes and their pathway(s), and the peripheral and central coding to umami taste are reviewed. The representation of umami in the human brain and the individual variation in detecting umami taste and associations with genotype are discussed. The presence of umami taste receptors in the gastrointestinal tract, and the interactions between the brain and gut are highlighted. The review concludes that more research is required into umami taste perception to include not only oral umami taste perception, but also the wider "whole body" signaling mechanisms, to explore the interaction between the brain and gut in response to umami perception and ingestion.

The sensory perception of food is a dynamic procedure, which is closely related to the released flavor stimuli. Thus, we evaluated the dynamic sensations of fresh and roasted salmon during the chewing process and investigated the tastants released in saliva. For fresh salmon, the fishy, umami, salty, and sweet attributes were perceived successively. Meanwhile, the smoky and fried flavors were the most dominant attributes of roasted salmon at the beginning, then various attributes were perceived. During the chewing process, free amino acids and 5′-nucleotides released in saliva were quantified. Compared to the sensory data, the results demonstrated that glutamic acid and inosine 5′-monophosphate released in saliva might induce the umami perception. The sweet-tasting amino acids alanine and glycine may contribute to sweetness. Therefore, we suggested that the time dimension of tastants dissolved in saliva would affect the dynamic sensation of food, even for complex food materials.

Clam is a kind of nutritious, delicious and economical aquatic food around the world and is famous for its unique aroma. Instrumental analysis, sensory analysis, and comprehensive statistical analysis were performed to explain the relationship between aroma and odorants in clam soup. Six extraction methods combined with GC-MS and sniffing were utilized to obtain the aroma fingerprints of clam soup and to analyze the correlation with aroma perception. Solvent extraction methods were more effective than headspace extraction methods for the volatiles of clam soup. SAFE was the best method to obtain the most comprehensive information of volatiles of clam soup. The sequence of a combination of different extraction methods and SAFE would also affect the results of volatiles extracted from clam soup. Volatiles extracted via SDE, P&T, and SPME would add further information to the result of SAFE. A total of 119 volatile compounds were identified from clam soup by summarising the results of different extraction methods. The significant effect of 14 key odorants in clam soup on aroma perception was verified by aroma recombination and odorant omission tests. A neural network diagram of the aroma profile was designed to visualize the information of odor perception. Furthermore, the results would be beneficial for aroma research studies of aquatic food and the processing of clam products.

Graphical abstract, Highlights • Unique salts with varying physicochemical properties were designed. • Salts were applied to a model system with a controlled surface area. • Transfer efficiency was driven by size, density and flow properties. • Loss from the product in packaging was driven by particle size. • Dissolution and/or saltiness were driven by size and hydrophobicity., Novel sodium reduction strategies are urgently required by the food industry. We hypothesised that redesigning salt crystals (size, density, hydrophobicity and flow properties) will offer a new route to increase saltiness and therefore reduce sodium. Eight salts were compared with different physicochemical properties, the resultant particles were characterised and adhesion to product, loss in-pack, rate of dissolution and ultimately saltiness perception were evaluated. Principle findings included that particle adhesion was driven by particle size (r = -0.85, p = 0.008), bulk density (r = -0.80, p = 0.017) and flow properties (r = 0.77, p = 0.015); loss in-pack was associated with particle size and hydrophobicity of the salt particle while dissolution and/or saltiness perception was also driven by particle size and hydrophobicity of the salt particle. The findings offer a new set of design rules for future ingredient design for the food and flavour industries.

Food flavour ingredients are required by law to obtain prior approval from regulatory bodies, such as the U.S. Food and Drug Administration (FDA) or the European Food Safety Authority (EFSA) in terms of toxicological data and intended use levels. However, there are no regulations for labelling the type and concentration of flavour additives on the product, primarily due to their low concentration in food and generally recognised as safe (GRAS) status determined by the flavour and extract manufacturers’ association (FEMA). Their status for use in e-cigarettes and other vaping products challenges these fundamental assumptions, because their concentration can be over ten-thousand times higher than in food, and the method of administration is through inhalation, which is currently not evaluated by the FEMA expert panel. This work provides a review of some common flavour ingredients used in food and vaping products, their product concentrations, inhalation toxicity and aroma interactions reported with different biological substrates. We have identified several studies, which suggest that the high concentrations of flavour through inhalation may pose a serious health threat, especially in terms of their cytotoxicity. As a result of the wide range of possible protein-aroma interactions reported in our diet and metabolism, including links to several non-communicable diseases, we suggest that it is instrumental to update current flavour- labelling regulations, and support new strategies of understanding the effects of flavour uptake on the digestive and respiratory systems, in order to prevent the onset of future non-communicable diseases.

Consumer sensory evaluation, aroma release analysis and biophysical protein analysis were used to investigate the effect of ethanol on the release and perception of flavour in beer (lager and stout) at different ethanol levels (0 and 5% ABV). Consumer study results showed no significant differences in orthonasal perception, yet retronasal results showed that 0% lager was perceived as maltier with reduced fruitiness, sweetness, fullness/body and alcohol warming sensation (p P, the presence of α-amylase selectively reduces the headspace concentration of hydrophobic compounds. It was found that ethanol has a subtle inhibitory effect on the binding of hydrophobic compounds to α-amylase, thereby increasing their headspace concentration in the 5% ABV as compared to the 0% beers. This synergistic ethanol * saliva effect is attributed to the changes in the conformation of α-amylase due to ethanol-induced denaturation. It is hypothesised that the partially unfolded protein structures have a lower number of hydrophobic pockets, leading to a lower capacity to entrap hydrophobic aroma compounds. This supports the hypothesis that ethanol * saliva interactions directly impact the sensory and flavour properties of beer, which would provide a basis for further investigations in reformulation of 0% ABV drinks.

Aroma compounds are diverse low molecular weight organic molecules responsible for the flavour of food, medicines or cosmetics. Natural and artificial aroma compounds are manufactured and used by the industry to enhance the flavour and fragrance of products. While the low concentrations of aroma compounds present in food may leave no effect on the structural integrity of the mucosa, the effect of concentrated aroma volatiles is not well understood. At high concentrations, like those found in some flavoured products such as e-cigarettes, some aroma compounds are suggested to elicit a certain degree of change in the mucin glycoprotein network, depending on their functional group. These effects are particularly associated with carbonyl compounds such as aldehydes and ketones, but also phenols which may interact with mucin and other glycoproteins through other interaction mechanisms. This study demonstrates the formation of such interactions in vitro through the use of molecular hydrodynamics. Sedimentation velocity studies reveal that the strength of the carbonyl compound interaction is influenced by compound hydrophobicity, in which the more reactive short chain compounds show the largest increase in mucin-aroma sedimentation coefficients. By contrast, the presence of groups that increases the steric hindrance of the carbonyl group, such as ketones, produced a milder effect. The interaction effects were further demonstrated for hexanal using size exclusion chromatography light scattering (SEC-MALS) and intrinsic viscosity. In addition, phenolic aroma compounds were identified to reduce the sedimentation coefficient of mucin, which is consistent with interactions in the non-glycosylated mucin region.

Oral temperature, tongue specifically, is a key factor affecting oral sensation and perception of food flavour and texture. It is therefore very important to know how the tongue temperature is affected by food consumption. Unfortunately, traditional methods such as clinical thermometers and thermocouples for oral temperature measurement are not most applicable during food oral consumption due to its invasive nature and interference with food. In this study, infrared thermal (IRT) imager was investigated for its feasibility for the measurement of tongue surface temperature. The IRT technique was firstly calibrated using a digital thermometer (DT). The technique was then used to measure tongue surface temperature after tongue was stimulated by (1) water rinsing at different temperatures (0–45 °C); and (2) treated with capsaicin solutions (5, 10, and 20 ppm). For both cases, tongue surface temperature showed significant changes as a result of the physical and chemical stimulation. Results confirm that IRT is feasible for tongue temperature measurement and could be a useful supporting tool in future for the study of food oral processing and sensory perception.

© Copyright © 2020 McAusland, Lim, Morris, Smith-Herman, Mohammed, Hayes-Gill, Crowe, Fisk and Murchie. Advancements in availability and specificity of light-emitting diodes (LEDs) have facilitated trait modification of high-value edible herbs and vegetables through the fine manipulation of spectra. Coriander (Coriandrum sativum L.) is a culinary herb, known for its fresh, citrusy aroma, and high economic value. Studies into the impact of light intensity and spectrum on C. sativum physiology, morphology, and aroma are limited. Using a nasal impact frequency panel, a selection of key compounds associated with the characteristic aroma of coriander was identified. Significant differences (P < 0.05) were observed in the concentration of these aromatics between plants grown in a controlled environment chamber under the same photosynthetic photon flux density (PPFD) but custom spectra: red (100%), blue (100%), red + blue (RB, 50% equal contribution), or red + green + blue (RGB, 35.8% red: 26.4% green: 37.8% blue) wavelengths. In general, the concentration of aromatics increased with increasing numbers of wavelengths emitted alongside selective changes, e.g., the greatest increase in coriander-defining E-(2)-decenal occurred under the RGB spectrum. This change in aroma profile was accompanied by significant differences (P < 0.05) in light saturated photosynthetic CO2 assimilation, water-use efficiency (Wi), and morphology. While plants grown under red wavelengths achieved the greatest leaf area, RB spectrum plants were shortest and had the highest leaf:shoot ratio. Therefore, this work evidences a trade-off between sellable commercial morphologies with a weaker, less desirable aroma or a less desirable morphology with more intense coriander-like aromas. When supplemental trichromatic LEDs were used in a commercial glasshouse, the majority of compounds, with the exception of linalool, also increased showing that even as a supplement additional wavelength can modify the aromatic profile increasing its complexity. Lower levels of linalool suggest these plants may be more susceptible to biotic stress such as herbivory. Finally, the concentration of coriander-defining aromatics E-(2)-decenal and E-(2)-hexenal was significantly higher in supermarket pre-packaged coriander leaves implying that concentrations of aromatics increase after excision. In summary, spectra can be used to co-manipulate aroma profile and plant form with increasing spectral complexity leading to greater aromatic complexity and intensity. We suggest that increasing spectral complexity progressively stimulates signaling pathways giving rise to valuable economic traits.

Foxtail millet has become popular over recent years for its nutritional value and ecological functions. The aroma of foxtail millet is not well characterized, which is critical for its eating quality and understanding the biochemistry and genetics of aroma is important for molecular breeding of millets rich in aroma. In this study, the volatile aroma compounds of the elite millet variety Jingu 21 were investigated at different cooking times, pH, processing methods, and compared with 3 other varieties. An in-vial cooking method was developed which combined solid phase micro-extraction and gas chromatography-mass spectrometry for the detection and identification of volatile compounds. The main findings were: a) Twelve aroma compounds were identified during cooking, which were hexanal, heptanal, octanal, (E)-2-heptenal, nonanal, trans-2-octenal, trans-2-nonenal, 2,4-nonadienal, (E,E)-2,4-decadienal, 1-octen-3-ol, 2-pentylfuran and 6-methyl-5- hepten-2-one. b) Longer cooking times produced higher concentrations of aroma compounds. c) Variations in cooking pH (from 6 to 8) had no obvious impact on the aroma of the millet porridge. d) More volatile compounds were released from millet flour compared to millet grain. e) There were significant differences among varieties and Jingu 21 millet showed the highest abundance of most aroma compounds, explaining partly why it is strongly favored by consumers for decades.

Hyperspectral imaging (1000–2500 nm) was used for rapid prediction of moisture and total lipid content in intact green coffee beans on a single bean basis. Arabica and Robusta samples from several growing locations were scanned using a “push-broom” system. Hypercubes were segmented to select single beans, and average spectra were measured for each bean. Partial Least Squares regression was used to build quantitative prediction models on single beans (n = 320–350). The models exhibited good performance and acceptable prediction errors of ∼0.28% for moisture and ∼0.89% for lipids. This study represents the first time that HSI-based quantitative prediction models have been developed for coffee, and specifically green coffee beans. In addition, this is the first attempt to build such models using single intact coffee beans. The composition variability between beans was studied, and fat and moisture distribution were visualized within individual coffee beans. This rapid, non-destructive approach could have important applications for research laboratories, breeding programmes, and for rapid screening for industry., Graphical abstract Image 1, Highlights • Intact single green coffee beans were analysed for their moisture and fat content by HSI. • NIR Hyperspectral imaging was applied to develop PLS calibrations for these constituents. • The PLSR performance showed a performance comparable with traditional NIR instrumentation. • A classification model was successfully applied by PLS-DA to discriminate Arabica vs Robusta.

Takifugu rubripes is well-known for its unique flavour but can also develop a putrid off-note. To eliminate off-note and promote desirable flavour, four cooking processes (boiling, steaming, microwave-heating and roasting) were explored to determine their effects on cooked T. rubripes. The temperature and water dynamics, physico-chemical properties were analysed and correlated with sensory qualities. The changes of centre temperature dynamics during cooking decreased the water mobility and led to varied sensory properties. Six out of ten orthonasal aroma attributes and four out of five mouthfeel attributes were significantly different among samples (p < 0.05). Based on partial least squares regression analysis, orthonasal aroma attributes “roasted” and “earthy/putrid fish” highly correlated with the volatile compounds generated from Maillard reaction and lipid oxidation, respectively; meanwhile mouthfeel attributes of chewy/fibre and tender/juicy were highly associated with water loss and moisture, respectively. This study provides insights for optimising cooking conditions to create desirable fish flavour.

Highlights • HSI was applied for non-destructive prediction of total protein content in wheat kernels. • Above 2100 wheat kernels were taken from ~200 batches and individually analysed. • PLS regression models had R2 = 0.82 and prediction error lower than 0.93%. • Protein distribution had wide range (6–20%) and was visualised by applying the calibration. • The performance of HgGcTe was superior to the one built by simulating InGaAs sensors., Hyperspectral imaging (HSI) combines Near-infrared (NIR) spectroscopy and digital imaging to give information about the chemical properties of objects and their spatial distribution. Protein content is one of the most important quality factors in wheat. It is known to vary widely depending on the cultivar, agronomic and climatic conditions. However, little information is known about single kernel protein variation within batches. The aim of the present work was to measure the distribution of protein content in whole wheat kernels on a single kernel basis, and to apply HSI to predict this distribution. Wheat samples from 2013 and 2014 harvests were sourced from UK millers and wheat breeders, and individual kernels were analysed by HSI and by the Dumas combustion method for total protein content. HSI was applied in the spectral region 980–2500 nm in reflectance mode using the push-broom approach. Single kernel spectra were used to develop partial least squares (PLS) regression models for protein prediction of intact single grains. The protein content ranged from 6.2 to 19.8% (“as-is” basis), with significantly higher values for hard wheats. The performance of the calibration model was evaluated using the coefficient of determination (R2) and the root mean square error (RMSE) from 3250 samples used for calibration and 868 used for external validation. The calibration performance for single kernel protein content was R2 of 0.82 and 0.79, and RMSE of 0.86 and 0.94% for the calibration and validation dataset, enabling quantification of the protein distribution between kernels and even visualisation within the same kernel. The performance of the single kernel measurement was poorer than that typically obtained for bulk samples, but is acceptable for some specific applications. The use of separate calibrations built by separating hard and soft wheat, or on kernels placed on similar orientation did not greatly improve the prediction ability. We simulated the use of the lower cost InGaAs detector (1000–1700 nm), and reported that the use of proposed HgCdTe detectors over a restricted spectral range gave a lower prediction error (RMSEC = 0.86% vs 1.06%, for HgCdTe and InGaAs, respectively), and increased R2 value (Rc2 = 0.82 vs 0.73).

Hyperspectral imaging (HSI) combines spectroscopy and imaging, providing information about the chemical properties of a material and their spatial distribution. It represents an advance of traditional Near-Infrared (NIR) spectroscopy. The present work reviews the most recent applications of NIR spectroscopy for cereal grain evaluation, then focused on the use of HSI in this field. The progress of research from ground material to whole grains and single kernels is detailed. The potential of NIR-based methods to predict protein content, sprout damage and α-amylase activity in wheat and barley is shown, in addition to assessment of quality parameters in other cereals such as rice, maize and oats, and the estimation of fungal infection. This analytical technique also offers the possibility to rapidly classify grains based on properties such as variety, geographical origin, kernel hardness, etc. Further applications of HSI are expected in the near future, for its potential for rapid single-kernel analysis.

The incorporation of probiotics and bioactive compounds, via plasticised thin-layered hydrocolloids, within food products has recently shown potential to functionalise and improve the health credentials of processed food. In this study, choice of polymer and the inclusion of whey protein isolate was evaluated for their ability to stabalise live probiotic organisms. Edible films based on low (LSA) and high (HSA) viscosity sodium alginate, low esterified amidated pectin (PEC), kappa-carrageenan/locust bean gum (κ-CAR/LBG) and gelatine (GEL) in the presence or absence of whey protein concentrate (WPC) were shown to be feasible carriers for the delivery of L. rhamnosus GG. Losses of L. rhamnosus GG throughout the drying process ranged from 0.87 to 3.06 log CFU/g for the systems without WPC, losses were significantly reduced to 0 to 1.17 log CFU/g in the presence of WPC. Storage stability (over 25d) of L. rhamnosus GG at both tested temperatures (4 and 25 °C), in descending order, was κ-CAR/LBG > HSA > GEL > LSA = PEC. In addition, supplementation of film forming agents with WPC led to a 1.8- to 6.5-fold increase in shelf-life at 4 °C (calculated on the WHO/FAO minimum requirements of 6 logCFU/g), and 1.6–4.3-fold increase at 25 °C. Furthermore probiotic films based on HSA/WPC and κ-CAR/LBG/WPC blends had both acceptable mechanical and barrier properties., Graphical abstract L. rhamnosus GG survival in edible films – the interrelation between the physical and optical film properties and L. rhamnosus GG survival during storage.Image 1, Highlights • Whey protein concentrate (WPC) inclusion enhanced survival during drying and storage. • WPC inclusion reduced water vapour permeability and Tg. • Cell viability was greatest in pectin/WPC films during drying. • Cell viability was greatest in composite carrageenan/locust bean gum/WPC films during storage.

Vancomycin, a branched tricyclic glycosylated peptide antibiotic, is a last-line defence against serious infections caused by staphylococci, enterococci and other Gram-positive bacteria. Orally-administered vancomycin is the drug of choice to treat pseudomembranous enterocolitis in the gastrointestinal tract. However, the risk of vancomycin-resistant enterococcal infection or colonization is significantly associated with oral vancomycin. Using the powerful matrix-free assay of co-sedimentation analytical ultracentrifugation, reinforced by dynamic light scattering and environmental scanning electron microscopy, and with porcine mucin as the model mucin system, this is the first study to demonstrate strong interactions between vancomycin and gastric and intestinal mucins, resulting in very large aggregates and depletion of macromolecular mucin and occurring at concentrations relevant to oral dosing. In the case of another mucin which has a much lower degree of glycosylation (~60%) – bovine submaxillary mucin - a weaker but still demonstrable interaction is observed. Our demonstration - for the first time - of complexation/depletion interactions for model mucin systems with vancomycin provides the basis for further study on the implications of complexation on glycopeptide transit in humans, antibiotic bioavailability for target inhibition, in situ generation of resistance and future development strategies for absorption of the antibiotic across the mucus barrier., The authors are grateful for a grant from the Independent Diabetes Trust (G.G.A. and S.E.H.) and the Engineering and Physical Sciences Research Council, grant number EP/L015633/1 (I.F., S.E.H., G.G.A., V.D.).

β-Glycosidases enhance wine aroma by releasing volatile aglycones from non-volatile glycosides. Commercial preparations contain primarily pectinases, with β-glycosidase as a secondary activity, which limits their potential. Here, the extremophilic β-glucosidase A from Halothermothix orenii, (BglA) has been compared with Rapidase® for the production of aromatic wines and in the remediation of smoke-tainted wines. Model systems, real juices and wines have been enriched with geranyl glucoside, typical of white varieties, and guaiacyl glucoside, commonly found in red wines exposed to oak and wines made from grapes exposed to smoke. The hydrolytic capacity of BglA was evaluated by measuring the released volatiles in the gas phase with solid-phase microextraction and GC–MS. BglA, despite an apparent instability at low pH, is twice as effective in releasing volatiles in sweeter wines and in grape juices, offering an excellent alternative for the early stages of the winemaking process and in the juice industry.

Graphical abstract, Highlights • The impact of capsaicin on aroma release was evaluated in a model system. • Capsaicin did not modify equilibrium gas-liquid partitioning of aroma compounds. • Capsaicin enhanced saliva secretion by 75% • Capsaicin decreased in-nose aroma release of 3-methylbutanal, 1-octen-3-ol, and linalool. • Capsaicin induced physiological changes (saliva flow) directly impacted aroma release., Capsaicin is the main bioactive compound in chili pepper that leads to the perception of “spiciness”. However, the effect of capsaicin on aroma release in the nose remains unexplained. This is the first study designed to measure capsaicin’s impact on aroma release during consumption. In vitro studies, using static headspace analysis by atmospheric pressure chemical ionization-mass spectrometry (APCI-MS), showed no impact of capsaicin (5 ppm) on the gas-liquid partitioning equilibria of a range of aroma compounds. However, a significant reduction in aroma release was observed in vivo, during oral melting of a model ice cube system (p

Highlights • Heat-treatment of protein ingredients can impart sulfurous flavours into beverages. • Sulfurous flavours negatively impacted consumer acceptance of a dairy beverage. • Older adults had greater acceptance of sulfurous flavours compared to younger adults. • Diacetyl reduced the negative impact of these compounds for both age groups. • Best estimate thresholds give a conservative estimate of off-flavour acceptability., Many older adults fail to meet their daily protein requirements, potentially due to social, physical and medical factors, including sensory and appetite changes. Additionally, our previous research has identified potential sulfurous off-flavours, originating from heat-treatment of protein ingredients, which could play a role in consumer acceptance. This study aims to determine the hedonic impact of these potential off-flavours when added to a dairy beverage, identify the specific off-flavour concentrations which cause rejection by consumers, and lastly investigate difference in acceptance between older and younger consumers. A rejection threshold (RjT) protocol was used, in combination with Best Estimate Thresholds (BET), whereby sulfurous flavours (dimethyl sulfide, dimethyl disulfide and dimethyl trisulfide), and diacetyl were added to create a range of concentrations. 95 participants (younger n = 49, 18–38 years; older n = 46, 60–79 years) tasted 7 pairs of samples (one blank and one with ascending off-flavour concentration) and selected their preferred samples. Sulfurous flavours negatively impacted consumer acceptance, however, the extent to which they impart a negative effect differs between age groups. Younger adults rejected samples containing low concentrations of sulfurous off-flavours (1.55 ppb), however, older adults rejected samples with concentrations over 3 times higher (5.08 ppb). When combined with sulfurous flavours, diacetyl increased the rejection threshold for both groups. In conclusion, these observations imply that a greater quantity of off-flavour may be present before acceptance is reduced in the older consumer group. Moreover, diacetyl demonstrates partial masking abilities of sulfurous off-flavours, and BET gave a more conservative estimate of acceptability. This knowledge will help guide sensory innovation of high-protein beverages for older consumers to support product acceptance and optimal intake.

Highlights • Quantitative calibrations were built from shelled and in-shell single cocoa beans by HSI. • The fat content of commercial batches of cocoa beans varies by up to 15% within batches. • HSI prediction of the total lipid content was successful for shelled and unshelled beans. • Segregation using HSI fat calibration enhanced cocoa bean fat content by 6%., This work aimed to explore the possibility of predicting total fat content in whole dried cocoa beans at a single bean level using hyperspectral imaging (HSI). 170 beans randomly selected from 17 batches were individually analysed by HSI and by reference methodology for fat quantification. Both whole (i.e. in-shell) beans and shelled seeds (cotyledons) were analysed. Partial Least Square (PLS) regression models showed good performance for single shelled beans (R2 = 0.84, external prediction error of 2.4%). For both in-shell beans a slightly lower prediction error of 4.0% and R2 = 0.52 was achieved, but fat content estimation is still of interest given its wide range. Beans were manually segregated, demonstrating an increase by up to 6% in the fat content of sub-fractions. HSI was shown to be a valuable technique for rapid, non-contact prediction of fat content in cocoa beans even from scans of unshelled beans, enabling significant practical benefits to the food industry for quality control purposes and for obtaining a more consistent raw material.

This study highlights the changes in umami-related nucleotide and glutamate levels when the AMP deaminase gene was elevated in transgenic tomato. Taste is perceived as one of a combination of five sensations, sweet, sour, bitter, salty, and umami. The umami taste is best known as a savoury sensation and plays a central role in food flavour, palatability, and eating satisfaction. Umami flavour can be imparted by the presence of glutamate and is greatly enhanced by the addition of ribonucleotides, such as inosine monophosphate (IMP) and guanosine monophosphate (GMP). The production of IMP is regulated by the enzyme adenosine monophosphate (AMP) deaminase which functions to convert AMP into IMP. We have generated transgenic tomato (Solanum lycopersicum) lines over expressing AMP deaminase under the control of a fruit-specific promoter. The transgenic lines showed substantially enhanced levels of AMP deaminase expression in comparison to the wild-type control. Elevated AMP deaminase levels resulted in the reduced accumulation of glutamate and increased levels of the umami nucleotide GMP. AMP concentrations were unchanged. The effects on the levels of glutamate and GMP were unexpected and are discussed in relation to the metabolite flux within this pathway.

In the present work, the intragastric structuring ability of o/w emulsions either stabilised (1–4%, w/w of sodium alginate (SA)) or structured with sheared ionic gel (1–3%, w/w of SA crosslinked with Ca2+) in the absence (saliva and gastric phases constituted of deionised water) or presence of in vitro pre-absorptive conditions (physiological simulated saliva and gastric fluids) was investigated. Visualisation of the morphological aspects of the gastric chymes, in the absence of multivalent counterions, demonstrated that SA stabilised systems underwent a remarkable swelling in the pH range of 2–3, whilst at the same pH range, ionic SA gel structured systems maintained their major structure configuration. When the aforementioned systems were exposed to physiological intragastric fluids, a reduction of the length and the hydrodynamic volume of the alginate fibres was detected regardless the structuring approach. On their exposure to physiological intragastric conditions (pH = 2), SA stabilised emulsions underwent sol–gel transition achieving a ca. 3- to 4-order increase of storage modulus (at 1 Hz). In the case of ionic sheared gel structured emulsions, exposure to physiological intragastric fluids resulted in a 10-fold reduction ability of their acid structuring ability, most likely due to the dialysis of egg-box dimer conformations by monovalent cations and protons and the sterical hindering of hydrogen bonding of MM and GG sequences under acidic conditions. Using of non-physiological simulated intragastric fluids was associated with overestimated structuring performance of SA regardless its physical state.

Capsaicin is the main component in chilli pepper, which contributes to the spiciness of the food. However, the role of capsaicin on aroma perception has been controversial in the literature. This is the first study exploring the impact of capsaicin on aroma release and perception simultaneously. Flavoured solutions with 3-methylbutanal (nutty note) were made with or without 5 mg/L capsaicin. Real-time APCI-MS analysis was applied to investigate in-nose aroma release during and after consumption of the solutions, and sensory tests were simultaneously conducted to reveal any temporal perception changes over 60 s. The results from 15 participants with triplicates indicated that capsaicin had no significant impact on aroma concentration from aqueous solutions, but the aroma perception rating was significantly higher (p, Graphical abstract Image 1, Highlights • Capsaicin's impact on aroma release and simultaneous perception was investigated. • Flavoured solutions of 3-methylbutanal were made with or without capsaicin. • Capsaicin had no significant impact on the in-nose aroma release concentration. • Capsaicin significantly enhanced aroma perception by 45% during 60s observation. • Participants with lower saliva flow also had lower spiciness and aroma ratings.

During storage of coffee, the key aroma 2-furfurylthiol becomes less active, the mechanisms of this loss and ways to mitigate it were investigated. Aroma profiles were analyzed using GC–MS and sensory properties were evaluated by Quantitative Descriptive Analysis. Quinones, as the oxidation products of hydroxydroquinone, was found to actively bind 2-furfurylthiol, which accounted for the loss of 2-furfurylthiol. To mitigate this loss, ingredients were screened for their ability to prevent 2-furfurylthiol from loss. Cysteine had the highest 2-furfurylthiol releasing efficiency and ascorbic acid was also selected due to its 2-furfurylthiol releasing ability in Fenton reaction system. Concentrations were optimized and the addition of 0.045 g/L cysteine and 0.05 g/L ascorbic acid directly protected aroma during storage, these included 2-furfurylthiol, dimethyltrisulfide, methyl furfuryl disulfide, 4-ethylguaiacol and 4-vinylguaiacol. Ultimately, sensory testing showed a direct enhancement in nutty, sulfurous and roasted aroma attributes, an increase in flavour intensity and preference over shelf life.

The demand for high quality and specialty coffee is increasing worldwide. In order to meet these demands, a more uniform and standardized quality assessment of coffee is essential. The aim of this study was to make a sensory scientific and chemical characterization of common roasting defects in coffee, and to investigate their potential relevance for consumers’ acceptance of coffee. To this end, six time-temperature roasting profiles based on a single origin Arabica bean were developed: one ‘normal’, representing a reference coffee free of defects, and five common roast defects (‘dark’, ‘light’, ‘scorched’, ‘baked’ and ‘underdeveloped’. The coffee samples obtained from these beans were evaluated by means of (1) aroma analysis by Gas Chromatography-Mass Spectrometry (GC–MS), (2) sensory descriptive analysis (DA) by trained assessors, and (3) hedonic and sensory evaluation by consumers using a Check-All-That-Apply (CATA) questionnaire. Multivariate analyses of aroma, DA, and CATA data produced similar sample spaces, showing a clear opposition of the light roast to the dark and scorched roasts), with the normal roast having average values of key aroma compounds. The DA data confirmed this indications and showed the normal roast to have a balanced sensory profile compared to the other defects. Importantly, the normal roast was also significantly preferred in the consumer test ( N = 83 ), and significantly associated to positive CATA attributes ‘Harmonic’, ‘Pleasant’, and ‘Balanced’. Taken overall, the results provide a solid basis for understanding chemical and sensory markers associated with common roasting defects, which coffee professionals may use internally in both quality control and product development applications.

While a good mucoadhesive biopolymer must adhere to a mucus membrane, it must also have a good unloading ability. Here, we demonstrate that the biopolymer pullulan is partially digested by human salivary α-amylase, thus acting as a controlled release system, in which the enzyme triggers an increased release of flavour. Our oral processing simulations have confirmed an increase in the bioavailability of aroma and salt compounds as a function of oral pullulan degradation, although the release kinetics suggest a rather slow process. One of the greatest challenges in flavour science is to retain and rapidly unload the bioactive aroma and taste compounds in the oral cavity before they are ingested. By developing a cationic pullulan analogue we have, in theory, addressed the “loss through ingestion” issue by facilitating the adhesion of the modified polymer to the oral mucus, to retain more of the flavour in the oral cavity. Dimethylaminoethyl pullulan (DMAE-pullulan) was synthesised for the first time, and shown to bind submaxillary mucin, while still retaining its susceptibility to α-amylase hydrolysis. Although DMAE-pullulan is not currently food grade, we suggest that the synthesis of a sustainable food grade alternative would be a next generation mucoadhesive targeted for the oral cavity.

Submaxillary mucin is a major component that defines the makeup and functionality of saliva. Understanding its structure and function during food intake is key to designing appropriate strategies for enhancing the delivery of flavour. In the present study, the hydrodynamic integrity of bovine submaxillary mucin was characterised under physiological and acidic conditions and it was shown to have a broad molecular weight distribution with species ranging from 100 kDa to over 2000 kDa, and a random coil type of conformation. A decrease in the pH of mucin appeared to result in aggregation and a broader molecular weight distribution, which was shown to correlate with a release of flavour compounds. Our study also provides indications that p-cresol may have an effect on the macromolecular integrity of mucin.

A low alcohol beer evoking similar sensory enjoyment as its higher alcohol counterpart is potentially an attractive proposition to breweries for increased sales volumes, as well as consumers due to health and societal reasons. This study aimed to determine the influence of ethanol on the temporal sensory characteristics and liking of beer as perceived by beer consumers. A commercial 0% ethanol concentration lager was spiked with ethanol to different concentrations (0.5%, 2.8%, 5% ethanol). Consumers (n = 101) indicated their liking using temporal liking (TL) methodology (rated throughout consumption) and overall liking (rated at the end of consumption). Consumers also denoted the sensory properties perceived using temporal Check-All-That-Apply (TCATA). Overall, liking data divided consumers into 3 clusters with different patterns of liking. As ethanol concentration increased from 0 to 5%, the TL time that best predicted overall liking shifted from 60 s to 10–20 s indicating that liking of higher alcohol products was decided earlier on in consumption. Data suggested that in a lower ethanol beer, a liking judgement may not be stabilized until later in the evaluation, while in high ethanol beers, a liking judgement, either positive or negative, stabilised more rapidly. TCATA results revealed different temporal sensory profiles among the different ethanol concentrations. As ethanol concentration increased, the citation of sweetness, fullness/body and alcohol warming sensation increased. However, the relationship between TCATA citations and TL varied among the three clusters highlighting that, in relation to ethanol concentration, different negative and positive sensory drivers of preference exist for different segments of consumers.

In this study, atmospheric pressure chemical ionisation-mass spectrometry (APCI-MS) was successfully applied to understand the effect of phenolic compounds on the release of olive oil aroma compounds. Eight aroma compounds were monitored under in-vivo and in-vitro dynamic conditions in olive oil with and without the addition of virgin olive oil (VOO) biophenols. Three model olive oils (MOOs) were set up with identical volatile compounds concentrations using a refined olive oil (ROO). Phenolics were extracted from VOOs and were added to two MOOs in order to obtain two different concentrations of phenolic compounds (P+ = 354 mg kg-1; P++ = 593 mg kg-1). Another MOO was without VOO biophenols (P-). Phenolic compounds impacted both the intensity and time of aroma release. In the in-vivo study, 1-penten-3-one, trans-2-hexenal and esters had lower release in the presence of higher levels of biophenols after swallowing. In contrast, linalool and 1-hexanol had a greater release. The more hydrophobic compounds had a longer persistence in the breath than the hydrophilic compounds. VOO phenolics-proline-rich proteins complexes could explain the binding of aroma compounds and consequently their decrease during analysis and during organoleptic assessment of olive oil.