Apple Sourness and Sweetness Intensities Standardized Using a General-purpose Standard Solution and a Taste Sensor System.

Taste is an essential factor for evaluating the quality of agricultural products. However, it is usually difficult to compare data acquired at different times or by different people because there is no invariant reference and because the evaluation methods are largely subjective. Here, we addressed these problems by developing a method for standardizing strawberry sourness and sweetness intensities using a taste sensor approach with a taste standard solution composed of sour and sweet compounds. This standard solution allows highly efficient sensor measurements because it contains the standard compounds citric acid and sucrose. In addition, we found that polyphenol destabilized the sensor response for strawberry sweetness, and its removal from the sample by appropriate treatment with polyvinylpolypyrrolidone allowed stable evaluation of the sweetness intensity. The taste sensor data obtained using this method were in good agreement with the chemical analysis values related to human sensory evaluation.

To enable the taste evaluation of many food samples at a time as well as the comparison of taste evaluation data acquired at different times, a standardization method for taste intensities was developed by a combination of a taste sensor system and a standard solution prepared with taste substances. In the case of tomato juices, citric acid, sucrose, and monosodium glutamate were used as standard taste substances for sourness, sweetness, and umami taste, respectively. Each standard point of the taste intensities was determined using only one standard solution including these standard substances. The taste intensity was described as a value on a scale based on discrimination thresholds of human gustation, where intensities of sourness, sweetness, and umami taste of the tomato juices were classified into multiple levels. Organoleptic evaluation supported these results. Validation for the present standardization method revealed that this approach has enough precision for practical tomato taste evaluation.

The taste of beer was measured using a taste sensing system with eight kinds of lipid membrane. The output from the sensor has high discriminating power and high correlation with taste substances in beer and sensory test by human. The estimation of the concentration of taste substances by multiple regression analysis was fairly well. The taste sensor also well estimated the result of sensory test of many keywords concerning beer taste.

A method for evaluating the umami taste intensity of green tea by a taste sensor system was established. Interference in the measurement from catechins was solved by removing the catechins from sample solutions with poly(vinylpolypyrrolidone). A 5.00 mM aqueous solution of glutamic acid monosodium salt was used as the standard solution. Sensor outputs were converted into EIT uma (estimated intensity of taste concerning umami) values. One unit on the EIT uma scale was defined as the amount of the sensor output corresponding to a difference in 1.2 times the concentration of the standard substance (glutamic acid monosodium salt). The umami taste intensity of green tea was classified into six grades on the EIT uma scale. Sensory tests proved that the EIT uma value had a high correlation to the human gustatory sense.

Grading the astringency of black tea by a taste sensor system was studied. The black tea samples manufactured in India and Sri Lanka were classified into ten steps on the basis of two standard solutions (0.65 mM and 0.26 mM EGCg aqueous solutions). An organoleptic test demonstrated that the sensor output was correlative to the human gustatory sense.

It is difficult to describe the taste of Processed Aconite Root (PAR) because it contains toxic compounds, and tasting poses some risk to the examiner. Therefore, there is no description of the taste of PAR in the latest Japanese Pharmacopoeia, although the taste of crude drugs has been regulated as a criterion for judgment. In this study, we revealed the objective taste of PAR by using a taste-sensing system. The PAR samples examined were classified into four types by how the samples were processed: PAR1 processed by autoclaving; PAR2-a processed by autoclaving after rinsing in salt (sodium chloride) solution; PAR2-h processed by heating after rinsing in calcium chloride solution; PAR3 processed by treating with hydrated lime after rinsing in salt solution. The most characteristic taste factor of PAR is an aftertaste of cationic bitterness, which was detected in all PAR sample solutions, even at the concentration of 0.1 mg/ml. In addition, anionic bitterness and saltiness were detected in all sample solutions at 1 mg/ml. Furthermore, umami was detected in the PAR1, PAR2-a, and PAR3 sample solutions at 1 mg/ml. Detailing the analyses of the four taste factors on the four sample types, we found each type has its own characteristic taste pattern. On the basis of these results, we proposed a method for discriminating one PAR type from another by using the system.

Challenges and opportunities in the use of low‐energy sugar replacers

A feeling of full-filment : Sensory and physiological processes involved in satiation

Determination of total arsenic, chromium, copper and manganese in hot spring waters containing highly complex matrices and interferences by electrothermal atomic absorption spectrometry (ETAAS) was carried out in the presence of Ni, Pd, Ni + Pd and Ni + Pd + citric acid (CA) as chemical modifiers. Pyrolysis and atomization temperatures of analytes in sample and aqueous standard solutions, atomization and background profiles of analytes in sample solutions were obtained with and without modifiers and compared with each other. Effects of mass and mass ratio of modifiers were also studied. Limit of detection (LOD), limit of quantification (LOQ) and characteristic masses (mo) of analytes were found in the presence and absence of modifiers. Among the tested modifier mixtures, the Ni + Pd + CA modifier mixture was found to be preferable for the determination of analytes. The lowest LOD and mo values obtained with Ni + Pd + CA were 0.8 μg L−1 and 32 pg for As, 0.5 μg L−1 and 5.0 pg for Cr, 0.6 μg L−1 and 18 pg for Cu and 0.4 μg L−1 and 4 pg for Mn, respectively. The percent relative error found was below 5% for the determination of the analytes by the proposed method in the certified reference materials (CRMs) of water (Spsww-1 and 1643e). Arsenic in CRMs and sample solutions was also determined by hydride generation atomic absorption spectrometry (HGAAS) for the purpose of comparing with As results obtained by ETAAS. Results of analytes in sample solutions were compared with national and international water quality guidelines such as WHO and US EPA values, as well as literature data.

Nanostructured films of poly(o-ethoxyaniline) POEA and sodium sulfonated polystyrene PSS produced by the layer-by-layer technique (LBL) have been employed as part of sensory units in a taste sensor system, also known as electronic tongue (ET). The sensitivity of these films to standard taste solutions has been investigated by means of electrical capacitance measurements. At this moment we have observed that the film architecture plays an important role on the film electrical response to different tastes, which also depended on the frequency of the input signal. For instance, the sensitivity of films to sour (HCl 5mM) and salty (NaCl 5 mM) tastes increased as the number of POEA/PSS layers increased when they were interrogated in low frequency (100 Hz). However, at higher frequencies, above 1 kHz, the film sensitivity seemed to be independent on the number of POEA/PSS layers. Also, we have investigated the performance of these films in terms of reprodueibility and repeatability of their electrical response to different tastes. In general, the electrical response of POEA/PSS films has been highly reproducible and repetitive independently on the film architecture and frequency of interrogation. An array containing five LBL POEA/PSS films with different numbers of polymeric layers was able to distinguish liquids according to their taste and was also able to quantify NaCl at concentrations much lower than the human detection capacity. Such results have been demonstrating the potentiality of these films on the development of taste sensor systems.

A fluorescent derivatization reaction for Diltiazem drug quantification based on the condensation reaction of citric or malonic acid with acetic anhydride, catalyzed by the tertiary amine group of Diltiazem, was developed. Excitation emission matrices (EEMs) of fluorescence of the pure solvent (ethanol), standard and sample solutions following a standard addition methodology were analysed by PARAFAC based methods (PARAFAC, PARAFAC2 and PARALIND) to obtain robust calibration methodologies. The quantification results of the sample were compared with the official US Pharmacopeia high performance liquid chromatography-ultraviolet method (USP HPLC-UV). Although the experimental sets of EEM show linearity deviations all the PARAFAC based methods allow correct robust estimation of Diltiazem concentration in pharmaceutical formulations. The closest results were: derivatization with citric acid and PARAFAC2 six components non-negativity constraint model with a detection limit of 0.088 ppm; and, derivatization with malonic acid and PARAFAC six components non-negativity constraint model with a detection limit of 0.066 ppm for the malonic acid was observed. The simultaneous utilization of the three PARAFAC methods gives further information about the intrinsic structure of the data sets under analysis, i.e., it works as an efficient diagnostic tool for the existence of non-linearity and colinearity.

Component loss during evaporation—reconstitution of organic environmental samples for gas chromatographic analysis

Sufu shows different taste profiles at different fermentation times. To understand the taste characteristics of sufu at different stages, the changes of the dominant taste substances and the correlation between physicochemical properties and taste substances were investigated. The results showed that 5′-cytidine monophosphate, bitter amino acids, lactic acid, citric acid, and acetic acid were the dominant taste substances throughout the fermentation process. At the end of fermentation, their contents were 19.15, 251.48, 96.70, 155.23, and 20.68 mg/100 g, respectively. The equivalent umami concentration value of the samples in the curing and post-fermentation stage exceeded about 83.35–240.61% the threshold of monosodium glutamate, which demonstrated that umami taste properties of sufu were intense. Glu, Val, tartaric acid, and acetic acid were considered as active substances in mature sufu, with taste activity values of 2.27, 1.04, 3.33, and 1.95, respectively. Principal component analysis based on physicochemical indexes can effectively distinguish different fermentation stages. Furthermore, there was a significant correlation between active substances and physicochemical indexes. Our findings could help to understand and improve the taste of sufu and provide a certain reference for evaluation of the taste characteristics of sufu. Novelty impact statement The taste substances accumulated were different in fermentation stages. The production of taste substances had a certain correlation with physicochemical indexes. The equivalent umami concentration value was higher than monosodium glutamate threshold in curing and post-fermentation stages. Glu, Val, tartaric acid, and acetic acid were effective active taste substances in the mature sufu.

Emissions-Flammenphotometrie im Einstrahl-Verfahren mit Kompensation von Strahlungsdichteschwankungen der Flammenemission

No Taste for Health: How Tastes are Being Manipulated to Favour Foods that are not Conducive to Health and Wellbeing