Human Sensory Evaluation Research Articles

High-performance bioelectronic tongue using ligand binding domain T1R1 VFT for umami taste detection

Numerous efforts have been made to measure tastes for various purposes. However, most taste information is still obtained by human sensory evaluation. It is difficult to quantify a degree of taste or establish taste standard. Although artificial taste sensors called electronic tongues utilizing synthetic materials such as polymers, semiconductors, or lipid membranes have been developed, they have limited performance due to their low sensitivity and specificity. Recently, bioelectronic tongues fabricated by integrating human taste receptors and nanomaterial-based sensor platforms have been found to have high performance for measuring tastes with human-like taste perception. However, human umami taste receptor is heterodimeric class C GPCR composed of human taste receptor type 1 member 1 (T1R1) and member 3 (T1R3). Such complicated structure makes it difficult to fabricate bioelectronic tongue. The objective of this study was to develop a protein-based bioelectronic tongue for detecting and discriminating umami taste with human-like performance using umami ligand binding domain called venus flytrap (VFT) domain originating from T1R1 instead of using the whole heterodimeric complex of receptors. Such T1R1 VFT was produced from Escherichia coli (E. coli) with purification and refolding process. It was then immobilized onto graphene-based FET. This bioelectronic tongue for umami taste (BTUT) was able to detect monosodium L-glutamate (MSG) with high sensitivity (ca. 1 nM) and specificity in real-time. The intensity of umami taste was enhanced by inosine monophosphate (IMP) that is very similar to the human taste system. In addition, BTUT allowed efficient reusable property and storage stability. It maintained 90% of normalized signal intensity for five weeks. To develop bioelectronic tongue, this approach using the ligand binding domain of human taste receptor rather than the whole heterodimeric GPCRs has advantages in mass production, reusability, and stability. It also has great potential for various industrial applications such as food, beverage, and pharmaceutical fields.

Ridgetail White Prawn (Exopalaemon carinicauda) K Value Predicting Method by Using Electronic Nose Combined with Non-linear Data Analysis Model

In this paper, ridgetail white prawn (Exopalaemon carinicauda) K value predicting model by electronic nose (EN) was studied. Human sensory evaluation (HSE), weight loss, color, total viable counts (TVC), GC-MS, and K value were examined to provide quality references for EN detection. EN responses to prawns were recorded and processed by principal component analysis (PCA) and stochastic resonance (SR). Results indicated that prawn K value rapidly increased due to microbiology propagation. The volatile gases emitted by prawns increased with the increase of storage time based on GC-MS results. PCA method could not discriminate the prawns in different qualities, and SR signal-to-noise ratio (SNR) maximum (SNRmax) values successfully discriminated all samples. K value predicting model was developed by linear fitting regression between K values and SNRmaxvalues (R2 = 0.97). The proposed method will promote the applications of EN in aquatic product quality rapid determination.

Study of golden pompano (Trachinotus ovatus) freshness forecasting method by utilising Vis/NIR spectroscopy combined with electronic nose

ABSTRACTGolden pompano (Trachinotus ovatus) quality forecasting method utilising Vis/NIR spectroscopy combined with electronic nose (EN) was investigated in this article. Responses of Vis/NIR spectroscopy and EN to pompanos stored at 4°C were measured for 6 days. Physical/chemical indexes including texture, total volatile basic nitrogen, pH, total viable counts, and human sensory evaluation were synchronously examined as quality references. Chemometric methods including principal component analysis (PCA) and stochastic resonance (SR) were employed for spectroscopic and EN data analysis. Physicochemical examination demonstrated that fish quality decreased rapidly during storage. PCA qualitatively classified freshness degree of pompano samples, while SR signal-to-noise ratio (SNR) spectrum using SNR maximum quantitatively characterised quality for all samples. Golden pompano quality predictive models were developed based on spectroscopy, EN, and spectroscopy combined with EN, respectively. Results demonstrated that the model developed based on spectroscopy combined with EN presented a forecasting accuracy of 93.3%.

Convolutional Neural Network based Estimation of Gel-like Food Texture by a Robotic Sensing System

This paper presents a robotic sensing system that evaluates the texture of gel-like food, in which not only mechanical characteristics, but also geometrical characteristics of the texture are objectively and quantitatively evaluated. When a human chews a gel-like food, the person perceives the changes in the shape and contact force simultaneously on the tongue. Based on their impression, they evaluate the texture. To reproduce this procedure using a simple artificial mastication robot, the pressure distribution of the gel-like food is measured, and the information associated with both the geometrical and mechanical characteristics is simultaneously acquired. The relationship between the value of the human sensory evaluation of the texture and the pressure distribution image is then modeled by applying a convolutional neural network. Experimental results show that the proposed system succeeds in estimating the values of a human sensory evaluation for 23 types of gel-like food with a coefficient of determination greater than 0.92.

The vulnerability of human sensory evaluation and the promising senses instrumentation

PurposeThe purpose of this paper is to evaluate subjectivity issue, particularly sensitivity variance and fatigue effect, in human sensory evaluation, as well as review the feasibility of human-independent quality system, using E-tongue and E-nose.Design/methodology/approachThe sensitivity level is evaluated by measuring the threshold of Acesulfame-K, while the fatigue effect is evaluated by measuring the accuracy level of evaluation through the time. The experiment was administered to six trained sensory panelists.FindingsThe experiment result shows that each panelist has a different level of sensitivity and tendency in evaluating samples containing Acesulfame-K. Furthermore, by simulating the panelists’ daily inspection, the fatigue effect is also found in one out of six panelists. The use of E-nose and E-tongue, may eliminate the subjectivity issue, supporting the development of human error-free quality system.Research limitations/implicationsThe research findings indicate the needs of human substitution-built into the quality system to avoid both of subjectivity and error judgment while defining the products quality. However, the small numbers of panelists as well as the unvalidated substitute instruments application in the target workcenter were the main limitation of this study. Human-independent quality system could be applied only when the instruments have been calibrated to human response in perceiving taste and odor.Originality/valueThe research finding supports the theory of human panels’ tradeoffs in a sensory analysis in terms of sensitivity level variance and fatigue. It has provided additional contributions to the existing theories as well as developed effective strategies for the development of the human-independent quality system.

Jumbo squid (Dosidicus gigas) quality enhancement using complex bio-preservative during cold storage

Effects of chitosan combined with nisin on quality enhancement in jumbo squid (Dosidicus gigas) were investigated during cold storage (4 ± 1 °C). 1% chitosan combined with different concentrations of nisin (0, 2 and 6 g/L) were utilized as preservatives. Changes in human sensory evaluation, GC–MS, total variable counts, and physiochemical indexes, including weight loss, colour, total volatile basic nitrogen and K value, were synchronously measured. Results demonstrated that 1% chitosan combined with 6 g/L nisin maintained high sensory scores, low moisture loss and volatile spoilage products. The optimized method also inhibited microbial propagation, nutrient (protein, nucleotides, etc) degradation, etc. This method is promising in aquatic products quality preservation.

Investigation on strawberry freshness by rapid determination using an artificial olfactory system

ABSTRACTIn this paper, strawberry freshness forecasting performed using artificial olfactory system (AOS) was investigated. Human sensory evaluation (HSE), firmness, total soluble sugar (TSS), and reducing sugar content (RSC) of the samples were examined to provide physical/chemical references for the AOS system. AOS responses to strawberry samples were measured and measurement data were analyzed by principal component analysis (PCA) and stochastic resonance (SR). Experimental results indicated that the PCA method qualitatively discriminated strawberry samples in different freshness levels. The strawberry freshness forecasting model was established based on AOS. The forecasting model successfully discriminated strawberry samples with regression coefficients of R2 = 0.98159. Validating experiment results indicated that the developed model using AOS presented a predictive accuracy of 92%.

Sensory quality evaluation for appearance of needle-shaped green tea based on computer vision and nonlinear tools.

Tea is one of the three greatest beverages in the world. In China, green tea has the largest consumption, and needle-shaped green tea, such as Maofeng tea and Sparrow Tongue tea, accounts for more than 40% of green tea (Zhu et al., 2017). The appearance of green tea is one of the important indexes during the evaluation of green tea quality. Especially in market transactions, the price of tea is usually determined by its appearance (Zhou et al., 2012). Human sensory evaluation is usually conducted by experts, and is also easily affected by various factors such as light, experience, psychological and visual factors. In the meantime, people may distinguish the slight differences between similar colors or textures, but the specific levels of the tea are hard to determine (Chen et al., 2008). As human description of color and texture is qualitative, it is hard to evaluate the sensory quality accurately, in a standard manner, and objectively. Color is an important visual property of a computer image (Xie et al., 2014; Khulal et al., 2016); texture is a visual performance of image grayscale and color changing with spatial positions, which can be used to describe the roughness and directivity of the surface of an object (Sanaeifar et al., 2016). There are already researchers who have used computer visual image technologies to identify the varieties, levels, and origins of tea (Chen et al., 2008; Xie et al., 2014; Zhu et al., 2017). Most of their research targets are crush, tear, and curl (CTC) red (green) broken tea, curly green tea (Bilochun tea), and flat-typed green tea (West Lake Dragon-well green tea) as the information sources. However, the target of the above research is to establish a qualitative evaluation method on tea quality (Fu et al., 2013). There is little literature on the sensory evaluation of the appearance quality of needle-shaped green tea, especially research on a quantitative evaluation model (Zhou et al., 2012; Zhu et al., 2017).

Identification of odorants in wood of Calocedrus decurrens (Torr.) Florin by aroma extract dilution analysis and two-dimensional gas chromatography-mass spectrometry/olfactometry.

General emissions of volatile organic compounds from wood are well investigated, but only limited information is available on the odor-active substances contained therein. To close this gap, we aimed at specifically elucidating the odorous constituents of wood from incense cedar [Calocedrus decurrens (Torr.) Florin]; this material is commonly used for the production of a range of products such as pencils and interior accessories. Targeted odorant analysis requires specialized techniques combining modern odorant analytical tools with human-sensory evaluation. Following this concept, the odor profile of the wood sample was first evaluated by human-sensory analyses. Then, the most potent wood odorants were characterized by means of gas chromatography-olfactometry and ranked according to their odor potency via aroma extract dilution analysis. With use of this approach, more than 60 odorous substances were detected, and the 22 most potent odorants were successfully identified by gas chromatography-mass spectrometry/olfactometry and two-dimensional gas chromatography-mass spectrometry/olfactometry. Among the main odorants found were a series of terpenes, several degradation products of fatty acids, and a number of odorants with a phenolic core moiety. Five odorants are reported here for the first time as wood odorants, such as γ-octalactone and 3-phenylpropanoic acid; thymoquinone was demonstrated for the first time to have a pencil-like odor quality.

Quantification of astringency for traditional Chinese medicine based on animal preference index and electronic tongue

Current evaluation method for astringency is mainly focused on human sensory evaluation. However, it is subjective, vague, and short of assessment indicators for objective quantification. In this paper, the quantification method for astringent intensity of traditional Chinese medicine was established based on the animal preference index and electronic tongue in vitro and in vivo. Firstly, the standard substance of astringency, tannic acid, was used for the methodology optimization and validation of two-bottle preference test. It was determined that the standard experimental animals were female rats of 140-180 g. The functional relationship between concentration of tannic acid and preference index was obtained Y= ln(1.682 6－0.441 66X), r=0.997 3. Then the typical astringent Chinese herbs Chebulae Fructus, Ardisiae Japonicae Herba, Canarii Fructus, Catechu, and Arecae Pericarpium were evaluated by the optimized method. Their corresponding concentration of tannic acid was converted by the concentration-preference index relationship through preference index. Their astringency was equivalent to 0.56, 0.29, 0.24, 0.34, 0.25 g•L⁻¹ tannic acid. Finally, the results were verified by electronic tongue. The correction analysis between Euclidean distance in PCA and preference index and concentration of tannic acid converted by samples showed a high correlation through pearson correlation analysis. The above results indicated that the method was objective, true and reliable. The method provided a reliable tool for the quantification of astringency and evaluation of taste masking effect for Chinese medicines, and also offered a new idea and model for the quantification of taste in the pharmaceutical and food fields.

Chinese Quince (Cydonia oblonga Miller) Freshness Rapid Determination Method Using Surface Acoustic Wave Resonator Combined with Electronic Nose

In this article, Chinese quince (Cydonia oblonga Miller) freshness determination method was investigated using surface acoustic wave resonator, electronic nose, and surface acoustic wave resonator combined with electronic nose. Human sensory evaluation and weight loss index were examined as freshness reference. Results indicated that quince freshness decreased during storage procedure. Surface acoustic wave resonator output frequency and electronic nose measurement data stochastic resonance signal-to-noise ratio Eigen values characterized quince quality under different storage time. Freshness predictive models were developed using surface acoustic wave resonator frequency, electronic nose signal-to-noise ratio spectrum Eigen values, and their hybrid model. Validating experiments results demonstrated that the hybrid predictive model presented higher predicting accuracy (R2 = 0.987) than other two models. The proposed method is promising in fruit quality rapid analysis.

Qualitative and quantitative analyses of arc characteristics in SMAW

This study was conducted to develop a quantitative evaluation system for arc characteristics such as arc stability and welding spatter generation related to shielded metal arc welding (SMAW) without human sensory evaluation. Factors that correspond to sensory evaluations by welders were investigated based on image processing. For the quantitative evaluation of arc stability, results show that the root mean square and the standard deviation of the arc center fluctuation, respectively, correspond to welders’ sensory evaluation at AC and DC discharges. For welding spatter generation, a method of counting white pixels in a binarized image evaluates the number and size of welding spatters which closely coincide with welders’ sensory evaluations.

木造校舎および事務所の床の鉛直荷重に対する性能と歩行振動に対する感覚評価との関係（第<b>1</b>報）

大スパン床における静的および振動性状を測定することを目的に，4つの木造校舎および2つの木造事務所の床を測定対象として，静的たわみおよび振動の実測を行い，曲げ剛性ならびに固有振動数，減衰比の算定を行った。設計上の床の初期たわみはスパンの約1/430～1/1100，クリープを考慮した床のたわみはスパンの約1/280～1/800であり，1つの小学校を除いていずれもたわみ制限値を下回っていた。また，梁または平行弦トラスの曲げ剛性の実験値は設計値より1.1～3.9倍大きかった。さらに，実際の建築物における床の1次固有振動数の実測値は9.5～12Hzであり，荷重を固定荷重とし，単純支持を境界条件として計算した梁の固有振動数は床の固有振動数の実験値よりも10～30％小さかったが，比較的精度よく推定できることがわかった。なお，減衰比は3.1～6.5％で，既往の研究と同じような値となっていた。

Instrumental and Sensory Analysis of the Properties of Traditional Chinese Fried Fritters

The quality of traditional Chinese fried fritters is typically measured using human sensory evaluation techniques and physicochemical indices, the process of which is laborious and time-consuming. This study aimed to investigate the relationship between instrumental parameters, sensory criteria, and physicochemical indices. Significant correlations were found using principle component analysis. Volume, fat, texture, palatability, and instrumental parameters (hardness, fracturability, springiness, and gumminess) were found to be the main factors influencing the quality of Chinese fried fritters by principal component analysis (PCA) and instrumental methods, which were satisfactory replacement for human evaluation in correlation testing.

Sensory and Hedonic Evaluation in Response to Food-Cue Exposure: The Case of Juicing Demonstration of Fresh Oranges

This study evaluated whether observing the orange squeezing (juicing) process can influence consumers’ sensory evaluations and hedonics of different forms of orange juice. The juicing process delivers cognitive (freshness) and physical (olfactory/visual) food cues. Three forms of orange juice were used in the experiment: fresh squeezed, not-from-concentrate, and from-concentrate. Participants were divided into two groups, with only one group observing the juicing process using a specially designed table-top juicer. Sensory evaluations of participants who did not observe the juicing process were not significantly different with the exception of color. The demonstration of the juicing process primed consumers to identify and evaluate fresh squeezed orange juice in terms of color, aroma, flavor, sweetness, and acidity. The results of an ordered logistic model indicated that consumer acceptance of orange juice was significantly linked to internal attributes such as flavor, sweetness, acidity, and pulp, and the acceptances were not significantly different by juice forms. This implied that food cues from the juicing process can affect human sensory evaluation of the cued food, but the food cues may not overwhelm, in particular when attributes of alternatives are almost homogeneous.

Monovarietal extra-virgin olive oil classification: a fusion of human sensory attributes and an electronic tongue

Olive oil quality grading is traditionally assessed by human sensory evaluation of positive and negative attributes (olfactory, gustatory, and final olfactory–gustatory sensations). However, it is not guaranteed that trained panelist can correctly classify monovarietal extra-virgin olive oils according to olive cultivar. In this work, the potential application of human (sensory panelists) and artificial (electronic tongue) sensory evaluation of olive oils was studied aiming to discriminate eight single-cultivar extra-virgin olive oils. Linear discriminant, partial least square discriminant, and sparse partial least square discriminant analyses were evaluated. The best predictive classification was obtained using linear discriminant analysis with simulated annealing selection algorithm. A low-level data fusion approach (18 electronic tongue signals and nine sensory attributes) enabled 100 % leave-one-out cross-validation correct classification, improving the discrimination capability of the individual use of sensor profiles or sensory attributes (70 and 57 % leave-one-out correct classifications, respectively). So, human sensory evaluation and electronic tongue analysis may be used as complementary tools allowing successful monovarietal olive oil discrimination.

Durable fragrance finishing on jute blended home-textiles by microencapsulated aroma oil

Jute fibres are conventionally treated with Jute Batching Oil (JBO), a petroleum based fibre lubricant prior to its processing into yarns. The typical kerosenic smell of JBO seriously affects the consumers’ acceptance of jute products particularly value-added hometextiles application. Eventually to invade into hometextiles market, jute products need to avoid such typical odour, though under current practice use of JBO is an integral part of jute fibre processing. To find out an alternate solution, innovative approach of durable aroma/fragrance finishing on jute based textiles has been thought of for masking its bad odour permanently in regards to high-end applications. The present study envisages development of Jasmine oil containing aroma microcapsules from Melamine-Formaldehyde and application of aroma microcapsules on jute-cotton blended fabric in order to impart durable aroma finish. Suitable cross-linker (binder) has also been identified for attaching microcapsule effectively onto ligno-cellulosic textile surface. Effect of partial de-lignification of jute fabric has been examined to improve the effectiveness of binder as well as durability of aroma finishing. Characterizations of aroma microcapsules and washing durability of aroma finish have been carried out using both analytical and human sensory evaluation methods.

Evaluation of umami taste in mushroom extracts by chemical analysis, sensory evaluation, and an electronic tongue system

Seventeen edible mushrooms commercially available in Korea were analysed for their umami taste compounds (5′-nucleotides: AMP, GMP, IMP, UMP, XMP; free amino acids: aspartic, glutamic acid) and subjected to human sensory evaluation and electronic tongue measurements. Amanita virgineoides featured the highest total 5′-nucleotide content (36.9±1.50mg/g), while monosodium glutamate-like components (42.4±6.90mg/g) were highest in Agaricus bisporus. The equivalent umami concentration (EUC) ranged from 1.51±0.42 to 3890±833mgMSG/g dry weight; most mushrooms exhibited a high umami taste. Pleurotus ostreatus scored the highest in the human sensory evaluation, while Flammulina velutipes obtained the maximum score in the electronic tongue measurement. The EUC and the sensory score from the electronic tongue test were highly correlated, and also showed significant correlation with the human sensory evaluation score. These results suggest that the electronic tongue is suitable to determine the characteristic umami taste of mushrooms.

Development of a novel oral jelly formulation for elderly patients

Deterioration of the swallowing function in elderly persons and drug refusal among the behavioral abnormalities in Alzheimer's disease (AD) are commonly reported. Therefore, we developed an easy-to-swallow jelly formulation of Donepezil HCl which AD patients can take as a dessert. The development process, however, was full of trade-off problems. (1) Need for evaluating the taste of a drug product vs. Safety of human sensory evaluation of the taste. The trade-off was resolved by using a taste sensor. (2) Speed of development vs. Safety of the manufacturing process. We put priority on the safety rather than speed, and a safer antioxidant agent was found. (3) Usability of the container for AD patients with dysphagia vs. Size of the container. We put priority on its being user-friendly rather than on the size and chose a stable wide-mouth cup. (4) Suitable texture of jelly for swallowing the drug product vs. Residual volume of jelly in the cup. We designed the texture so that the residual volume of jelly in the cup was reduced. (5) Easy peeling properties of aluminum seal vs. High sealing strength for sterilization. The sealing strength was adjusted so that it was adequate to sterilize the drug product. (6) One cup in a heat-sealed aluminum pillow package to prevent overdose vs. Seven cups in a pillow package. A single-dose package was relatively expensive, but it was chosen to assure safety. We faced many difficult trade-off problems in the development of process. However, they were resolved using technical innovations and a people-friendly policy. Finally, we were able to launch a novel oral jelly formulation for elderly patients.

Kiwi fruit (Actinidia chinensis) quality determination based on surface acoustic wave resonator combined with electronic nose

In this study, electronic nose (EN) combined with a 433 MHz surface acoustic wave resonator (SAWR) was used to determine Kiwi fruit quality under 12-day storage. EN responses to Kiwi samples were measured and analyzed by principal component analysis (PCA) and stochastic resonance (SR) methods. SAWR frequency eigen values were also measured to predict freshness. Kiwi fruit sample's weight loss index and human sensory evaluation were examined to characteristic its quality and freshness. Kiwi fruit's quality predictive models based on EN, SAWR, and EN combined with SAWR were developed, respectively. Weight loss and human sensory evaluation results demonstrated that Kiwi fruit's quality decline and overall acceptance decrease during the storage. Experiment result indicated that the PCA method could qualitatively discriminate all Kiwi fruit samples with different storage time. Both SR and SAWR frequency analysis methods could successfully discriminate samples with high regression coefficients (R = 0.98093 and R = 0.99014, respectively). The validation experiment results showed that the mixed predictive model developed using EN combined with SAWR present higher quality prediction accuracy than the model developed either by EN or by SAWR. This method exhibits some advantages including high accuracy, non-destructive, low cost, etc. It provides an effective way for fruit quality rapid analysis.