Evolution of Taste Compounds of Dezhou-Braised Chicken During Cooking Evaluated by Chemical Analysis and an Electronic Tongue System

Characteristics of Umami Taste of Soy Sauce Using Electronic Tongue, Amino Acid Analyzer, and MALDI-TOF MS

The objective of this study was to investigate the umami characteristics of soy sauce using electronic tongue evaluation and amino acid composition and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. The soy sauce peptides were isolated from soy sauce using XAD-16 macroporous resin combined with ethanol solution. The results showed that the soy sauce peptide fraction eluted by 60% ethanol (SS-60%) exhibited a prominent umami taste, and the umami scores were highly positively correlated with the amino acid nitrogen contents of soy sauces. The umami scores of SS-60% were significantly positively correlated with the contents of free amino acids. Especially, Phe showed the highest positive correlation with the umami scores. In addition, five characteristic ion peaks with m/z at 499, 561, 643, 649, and 855 were identified in the peptide mass fingerprinting. Therefore, this study provides new insights into the umami characteristics for the taste evaluation and reality identification of soy sauce.

Changes in quality characteristics and biogenic amine contents in beef by cooking methods

This study aimed to evaluate the changes in imported beef loin before and after cooking, depending on cooking methods, through quality characteristics, biogenic amine (BA) content analysis, and electronic tongue system. Sous-vide (SV), characterized by the least cooking loss, exhibited the highest water content at 64.11%. Pan-grilling (PG), air-frying (AF), and IR-grilling (IR) methods showed a range of water content from 46.90 to 54.19%. In the taste results by the electronic tongue, umami and saltiness were higher in the high cooking temperature methods (PG, AF, IR, and combined sous-vide + pan-grilling [SVP]) than SV (p < 0.05). Compared to the control, total BAs concentrations decreased by 67.32% (SV), 64.90% (AF), 62.46% (IR), and 50.64% (PG), and SVP showed the largest decrease of 68.64% (p < 0.05). Therefore, SVP was considered the most effective cooking method for reducing BAs and maintaining the quality characteristics of beef loin.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01650-9.

Technological tools for the measurement of sensory characteristics in food: A review

The use of technological tools, in the food industry, has allowed a quick and reliable identification and measurement of the sensory characteristics of food matrices is of great importance, since they emulate the functioning of the five senses (smell, taste, sight, touch, and hearing). Therefore, industry and academia have been conducting research focused on developing and using these instruments which is evidenced in various studies that have been reported in the scientific literature. In this review, several of these technological tools are documented, such as the e-nose, e-tongue, colorimeter, artificial vision systems, and instruments that allow texture measurement (texture analyzer, electromyography, others). These allow us to carry out processes of analysis, review, and evaluation of food to determine essential characteristics such as quality, composition, maturity, authenticity, and origin. The determination of these characteristics allows the standardization of food matrices, achieving the improvement of existing foods and encouraging the development of new products that satisfy the sensory experiences of the consumer, driving growth in the food sector. However, the tools discussed have some limitations such as acquisition cost, calibration and maintenance cost, and in some cases, they are designed to work with a specific food matrix.

Comparison of taste characteristics between koji mold-ripened cheese and Camembert cheese using an electronic tongue system

Koji mold, classified in the genus Aspergillus, is used to produce traditional Japanese fermented foods such as miso, soy sauce, and sake. In recent years, the application of koji mold to cheese ripening has attracted attention, and cheese surface-ripened with koji mold (koji cheese) has been studied. In this study, to evaluate the taste characteristics of koji cheese, an electronic tongue system was employed to measure the taste values of cheese samples ripened using 5 strains of koji mold in comparison with commercial Camembert cheese. All koji cheese samples exhibited lower sourness and greater bitterness, astringency, saltiness, and umami richness than the Camembert cheese samples. The intensity of each taste characteristic differed depending on the koji mold strain. These results indicate that koji cheese has a different taste value than conventional mold-ripened cheese. Furthermore, the results also indicate that various taste characteristics can be achieved by selecting different koji molds.

Analysis of volatile and non-volatile compound profiles of wintering radish produced in Jeju-island by different oven roasting temperatures and times using electronic nose and electronic tongue techniques via multivariate analysis

The present study is to investigate the non-volatile and volatile profiles in radish according to the different oven roasting processing. In non-volatile compound profiles, different roasting temperatures (140-200 °C) and times (5, 10, 15, and 20 min) influenced non-volatile compounds in radishes, and high temperature roasted radish represented obvious changes than low temperature roasted radish. In volatile profiles, high temperature roasted radish were generated a higher number of Maillard reactions-related volatiles, including furfurals and 2-ethyl-5-methylpyrazine, than low temperature roasted radish. In chemometrics results, a radish roasted at 200 °C for 20 min was the highest dissimilarity compared with the other roasted radishes. This study is believed to be the first research demonstrating comprehensive identification of changes in non-volatile/volatiles profiles in radish by various processes (different times and temperatures) of oven roasting for food applications.

Design fabrication of electrochemical sensor based on Ru(bpy)22+/SMWCNTs/Au/GCE electrode for the selective determination of 5′-guanosine monophosphate

5'-Guanosine monophosphate (5'-GMP) is one main source of freshness in broths. Herein, an electrochemical platform based on a novel ternary nanocomposite glassy carbon electrode modified with advantageously-united gold nanoparticles, 2,2'-bipyridine hydrated ruthenium (Ru(bpy)₂Cl₂) and sulfonated multi-walled carbon nanotubes (SMWCNTs)was prepared and used to detect 5'-GMP. After conditions optimization, the best performance of the electrochemical sensor was found in acidic media, including high specificity, sensitivity and selectivity. The electrochemical sensor exhibited a wide linear range under the optimal conditions. The enhanced sensitivity of this sensor was attributed to the Ru(bpy)₂Cl₂ and functionalized SMWCNTs that provided high electrical conductivity and electrocatalytic properties during electrochemical reaction. Precise analysis of 5'-GMP in actual broth samples showed satisfactory recovery. Thus, the sensor can be used in the market and food enterprises.

Bifidobacterium animalis A12, a Probiotic Strain That Promotes Glucose and Lipid Metabolism, Improved the Texture and Aroma of the Fermented Sausage

Bifidobacterium animalis A12 was used for the development of fermented sausage. The growth activity, tolerance, and enzyme activity of B. animalis A12 and its contribution to the texture and flavour of fermented sausages were evaluated. Additionally, the sensory texture, flavour components, and amino acid nutrients during the fermentation process were assessed. B. animalis had high tolerance to NaCl and nitrite, and B. animalis A12 had protease and lipase activities. The pH value of sausage fermented with B. animalis A12 was lower than that of sausage fermented without any fermentation strain. Hexanal, heptanal, decanal, cis-2-decanal, and 4-methoxy-benzaldehyde are the unique aldehydes flavour components of fermented sausages in the A12 group. The highest content of volatile flavour substances and amino acids, and the color and texture characteristics of fermented sausage in the experimental group at 18 h were better than those at other times. These results suggest that B. animalis A12 has the potential to be used as a starter culture for im-proving flavour and texture in fermented sausage.

Taste Compound Generation and Variation in Chinese Water Chestnut (Eleocharis dulcis (Burm.f.) Trin. ex Hensch.) Processed with Different Methods by UPLC-MS/MS and Electronic Tongue System

Chinese water chestnut (CWC) is popular among consumers due to its unique flavor and crisp and sweet taste. Thus far, the key substances affecting the taste compound of CWC are still unclear. In this study, we used UPLC-MS/MS and an electronic tongue system to study the effects of four typical steaming and cooking methods, cooking without peel for 10 min (PC), steaming without peel for 15 min (PS), cooking with peel for 30 min (WPC), steaming with peel for 30 min (WPS), on the taste compound generation and variation of CWC, and revealed the secret of its crisp and sweet taste. The results show that the electronic tongue can effectively identify the taste profile of CWC, and the effective tastes of CWC were umami, bitterness, saltiness, and sweetness. We screened 371 differential compounds from 640 metabolic species. Among them, nucleotides and their derivatives, carbohydrates, organic acids and their derivatives, and amino acids and their derivatives are closely related to the key taste of CWC, and these compounds affected the taste of CWC through six related metabolic pathways: oxidative phosphorylation and purine metabolism; alanine, aspartate, and glutamate; bile secretion; amino sugar and nucleotide sugar metabolism; the phenylpropane pathway; and toluene degradation. This study reveals the potential metabolic causes of taste compound generation and variation in the taste of CWC.

The Impact of Rearing Salinity on Flesh Texture, Taste, and Fatty Acid Composition in Largemouth Bass Micropterus salmoides

It is of great significance for the aquaculture industry to determine how rearing salinity impacts fish flesh quality. In the present study, largemouth bass was cultured in different salinities (0%, 0.3%, 0.9%) for 10 weeks, and the effect on flesh texture, flavor compounds, taste, and fatty acid composition was evaluated. We show that rearing salinity not only increased flesh water-holding capacity, but also enhanced muscle hardness, chewiness, gumminess, and adhesiveness, which was consistent with the finding in the shear value test. Morphology analysis further revealed that the effect of salinity on flesh texture was probably related to changes in myofibril diameter and density. As for the taste of the flesh, water salinity improved the contents of both sweet and umami amino acids, and reduced the contents of bitter amino acid. Meanwhile, the content of IMP, the dominant flavor nucleotide in largemouth bass muscle, was significantly higher in the 0.9% group. Interestingly, electronic-tongue analysis demonstrated that the positive effect of salinity on flavor compounds enhanced the umami taste and taste richness of flesh. Moreover, rearing salinity improved the contents of C20: 5n-3 (EPA) and C22: 6n-3 (DHA) in back muscle. Therefore, rearing largemouth bass in adequate salinity may be a practical approach to improving flesh quality.

High freezing rate improves flavor fidelity effect of hand grab mutton after short-term frozen storage

Taking the eutectic point as the final freezing temperature, the differences of flavor substances of in hand grab mutton (HGM) frozen at three rates of 0. 26 cm/h (−18°C), 0.56 cm/h (−40°C) and 2.00 cm/h (−80°C) were determined and analyzed. The results showed that the flavor of HGM decreased significantly after freezing. With the increase of freezing rate, the contents of aldehydes, alcohols, ketones, acids, esters, others, free amino acids and 5′-nucleotides were higher, and the content of specific substances was also generally increased. All samples from unfrozen and frozen HGM could be divided into four groups using an electronic nose based on different flavor characteristics. Seven common key aroma components were determined by relative odor activity value (ROAV), including hexanal, heptanal, octanal, nonanal, (E)-oct-2-enal, (2E,4E)-deca-2,4-dienal and oct-1-en-3-ol. The higher the freezing rate, the greater the ROAVs. Taste activity values calculated by all taste substances were far <1, and the direct contribution of the substances to the taste of HGM was not significant. The equivalent umami concentration of HGM frozen at −80°C was the highest. These findings indicated that higher freezing rate was more conducive to the retention of flavor substances in HGM, and the flavor fidelity effect of freezing at −80°C was particularly remarkable.

Taste Attributes of the “June Hairy Crab” Juveniles of Chinese Mitten Crab (Eriocheir sinensis) in Yangcheng Lake, China—A Pilot Study

This is the first report on the use of a taste sensing system to quantitatively evaluate the taste attributes of two groups of native “June hairy crab” juveniles (commonly referred to as “Liu-Yue-Huang”) of the Chinese mitten crab (Eriocheir Sinensis H. Milne Edwards, 1853) from a net enclosure culture area in Yangcheng Lake (lake culture) and aquaculture ponds near the lake (pond culture). We showed that umami was the predominant basic taste of steamed June hairy crabs, followed by bitterness and astringency. The intensity value of saltiness was aberrant and could not be determined using this system. The average values of aftertaste-U reached 8.7 and 10.7 in the male June hairy crabs from the lake and pond cultures, respectively, which was significantly higher than their respective aftertaste-B and aftertaste-A values (p < 0.01). Female crabs did not have aftertaste-B, while their aftertaste-U was significantly higher than aftertaste-A (p < 0.01). Although principal component analysis and linear discriminant analysis were not able to completely distinguish among crabs from different cultures, they could robustly distinguish between male and female crabs.

Mastication-Enhanced Taste-Based Classification of Multi-Ingredient Dishes for Robotic Cooking

Chefs frequently rely on their taste to assess the content and flavor of dishes during cooking. While tasting the food, the mastication process also provides continuous feedback by exposing the taste receptors to food at various stages of chewing. Since different ingredients of the dish undergo specific changes during chewing, the mastication helps to understand the food content. The current methods of electronic tasting, on the contrary, always use a single taste snapshot of a homogenized sample. We propose a robotic setup that uses the mixing to imitate mastication and tastes the dish at two different mastication phases. Each tasting is done using a conductance probe measuring conductance at multiple, spatially distributed points. This data is used to classify 9 varieties of scrambled eggs with tomatoes. We test four different tasting methods and analyze the resulting classification performance, showing a significant improvement over tasting homogenized samples. The experimental results show that tasting at two states of mechanical processing of the food increased classification F1 score to 0.93 in comparison to the traditional tasting of a homogenized sample resulting in F1 score of 0.55. We attribute this performance increase to the fact that different dishes are affected differently by the mixing process, and have different spatial distributions of the salinity. It helps the robot to distinguish between dishes of the same average salinity, but different content of ingredients. This work demonstrates that mastication plays an important role in robotic tasting and implementing it can improve the tasting ability of robotic chefs.

Effects of Different Dietary Carbohydrate Sources on the Meat Quality and Flavor Substances of Xiangxi Yellow Cattle

This study investigated the dietary supplementation of starches with different carbohydrate sources on the proximate composition, meat quality, flavor substances, and volatile flavor substances in the meat of Chinese Xiangxi yellow cattle. A total of 21 Chinese Xiangxi yellow steers (20 ± 0.5 months, 310 kg ± 5.85 kg) were randomly divided into three groups (control, corn, and barley groups), with seven steers per group. The control steers received a conventional diet (coarse forage type: whole silage corn at the end of the dough stage as the main source), the corn group received a diet with corn as the main carbohydrate source, and the barley group received a diet with barley as the main carbohydrate source. The experiment lasted for 300 d. and the means of the final weights in the control, corn, and barley groups were 290 kg, 359 kg, and 345 kg. The diets were isonitrogenous. The corn and barley groups reduced the moisture (p = 0.04) and improved the intramuscular fat content of the meat (p = 0.002). They also improved meat color (a*) (p = 0.01) and reduced cooking loss (p = 0.08), shear force (p = 0.002), and water loss (p = 0.001). There was no significant difference in the 5′-nucleotide content (p > 0.05), the equivalent umami concentration (EUC) (p = 0.88), and taste activity value (TAV) (p > 0.05) among the three groups. The 5′-IMP (umami) content was the highest in the 5′-nucleotide and its TAV > 1. The corn and barley groups improved the content of tasty amino acids (tAA, p < 0.001). The corn group had a higher content of sweet amino acids (SAA, p < 0.001) and total amino acids (TAA, p = 0.003). Corn and barley improved the levels of MUFA (p < 0.001), PUFA (p = 0.002), n-3 PUFA (p = 0.005), and n-6 PUFA (p = 0.020). The levels of alcohols, hydrocarbons, and aldehydes in the corn group were higher than in the barley and control groups (p < 0.001). The esters content in the corn group was higher than in the barley and control groups (p = 0.050). In conclusion, feeding corn or barley as a carbohydrate source can improve the nutrient content and taste. Feeding corn as a carbohydrate source can improve the content of free amino acids (Cys, Glu, Gly, Thr, Leu, Trp, Gln, Asn, and Asp), fatty acids (saturated fatty acid, monounsaturated fatty acid, polyunsaturated fatty acid, n-3PUFA, n-6PUFA, and total fatty acid), and volatile flavor substances (alcohols, aldehydes, acids, and hydrocarbons) to improve the flavor and meat quality.

Multiple Technologies Combined to Analyze the Changes of Odor and Taste in Daokou Braised Chicken during Processing

This study analyzed the changes of odor and taste in Daokou braised chicken during processing by GC-MS, GC-IMS, e-nose and e-tongue. The 75 and 55 volatile compounds identified in Daokou braised chicken by GC-MS and GC-IMS, respectively, included hydrocarbons, aldehydes, alcohols, terpenes, ketones, heterocyclics, esters, acids and phenols; among them, aldehydes, alcohols and ketones were the most abundant. The number and proportion of volatile compounds in Daokou braised chicken changed significantly (p < 0.05) in the process. The proportion of volatile compounds with animal fatty odor, such as aldehydes and alcohols, decreased, while that of esters, ketones and terpenes from spices with fruity fragrance increased, especially in the braising stage. An e-nose showed that the odor intensities of sulfur-containing and nitrogen oxide compounds were higher (p < 0.05) after the braising stage, but weakened after 2 h braising. An e-tongue showed that saltiness and richness increased significantly (p < 0.05) after braising. The results of these four techniques showed that braising promoted the release of flavor compounds, and was beneficial to salt penetration and umami release. However, long braising could lead to weakened flavor intensity and the introduction of bitterness and astringency. This study also found that GC-IMS and e-nose were more sensitive to trace compounds such as sulfur-containing and nitrogen oxide compounds, esters, acids and phenolics in Daokou braised chicken than GC-MS. The use of multiple technologies could provide more comprehensive flavor profiles for Daokou braised chicken during processing. This study provides insights into the control of flavor of Daokou braised chicken, and may be of practical relevance for the poultry industry.

A comprehensive study for taste and odor compounds using electronic tongue and nose in broccoli stem with different thermal processing

This study analyzed taste and odor profiles in broccoli stems with different methods of thermal processing using electronic tongue and electronic nose. In electronic tongue analysis, umami and bitterness were obviously changed upon thermal processing, however, saltiness, sweetness, and sourness showed slight variations. Between raw and thermally processed broccolis, microwaved broccoli showed the highest changes of tastes based on raw broccoli, however, blanched broccoli showed similar tastes to raw broccoli compared with the others. In electronic nose analysis, a total of 21 volatiles in broccolis were analyzed. Sulfur-containing volatiles were changed via thermal steps, and the generation and reduction of sulfur-containing compounds have occurred (i.e. methnaethiol, 2,4,5-trimethylthiazole). In addition, some of the thermal steps (oven-heating, microwave heating, air-frying) have occurred Maillard reaction, and thus pyridine was generated. Therefore, this study can provide flavor data in broccoli, and contribute to further research for flavor characteristics in broccoli using electronic sensors.

Taste compounds, affecting factors, and methods used to evaluate chicken soup: A review

The taste of chicken soup is dependent upon various taste substances and human senses. More than 300 nonvolatile compounds reportedly exist in chicken/chicken soup. The primary purpose of this review was to elaborate on the prominent taste substances, the taste evaluation methods, and the factors affecting the taste of chicken soup. Most taste-active compounds with taste descriptions and thresholds in chicken soup were summarized. The application of sensory evaluation, liquid chromatography, electronic tongue, and other evaluation methods in chicken soup taste analysis were elaborated. The effects of genetic constitution, preslaughter, processing, and storage on chicken soup taste had been discussed. Nucleotides (especially inosine 5'-monophosphate), amino acids and their derivatives, organic acids, sugars, and peptides play a vital role in the taste attributes of chicken soup. Combining of liquid chromatography and mass spectrometry enables qualitative and quantitative analysis of taste-active compounds in chicken soup, aiding the exploration of key taste-active compounds. The electronic tongue application helps the overall taste perception of the soluble taste-active compounds present in chicken soup samples. Postmortem aging and stewing for a prolonged duration are effective techniques for improving the taste quality of chicken soup. The washing of preprocessing, the cooking temperature of processing, and the storage conditions also exert a significant impact on the taste of chicken soup.

Electronic Tongue as a Correlative Technique for Modeling Cattle Meat Quality and Classification of Breeds

Discrimination and species identification of meat has always been of paramount importance in the European meat market. This is often achieved using different conventional analytical methods but advanced sensor-based methods, such as the electronic tongue (e-tongue), are also gaining attention for rapid and reliable analysis. The aim of this study was to discriminate Angus, domestic buffalo, Hungarian Grey, Hungarian Spotted cattle, and Holstein beef meat samples from the chuck steak part of the animals, which mostly contained longissimus dorsi muscles, using e-tongue as a correlative technique with conventional methods for analysis of pH, color, texture, water activity, water-holding capacity, cooking yield, water binding activity, and descriptive sensory analysis. Analysis of variance (ANOVA) was used to determine significant differences between the measured quality traits of the five-meat species after analysis with conventional analytical methods. E-tongue data were visualized with principal component analysis (PCA) before classifying the five-meat species with linear discriminant analysis (LDA). Significant differences were observed among some of the investigated quality parameter. In most cases, Hungarian Grey was most different from the other species. Using e-tongue, separation patterns could be observed in the PCA that were confirmed with 100% recognition and 97.5% prediction of all the different meat species in LDA.

Analysis of flavor formation during production of Dezhou braised chicken using headspace-gas chromatography-ion mobility spec-trometry (HS-GC-IMS)

In order to help the poultry industry to generate higher quality products, the headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) technique was used to identify volatile substances formed during the processing of Dezhou braised chicken (DBC). A total of 37 volatile substances including aldehydes, alcohols, ketones, esters, terpenoids, furans and pyrazines were identified during DBC processing across seven sampling stages. The analyses identified 2-ethylhexanol as a key flavor chemical within the chicken carcasses, and found that ethyl acetate, 1-hexanol, 4-methyl-2-pentanone and 1-pentanol were mainly produced during the deep-frying stage of processing. Stewing with herbs and spices was found to be an important stage in the flavor impartation process. 2-Butanone, n-nonanal, heptanal and ethanol were positively related to processing stage 3, whereas processing stage 4 was characterized by ethyl propanoate, benzaldehyde, butyl acetate, 2-pentyl furan and 2-heptanone. The processing stages 5, 6 and 7 were not significantly different (P > 0.05) from each other.

Taste compounds generation and variation of broth in pork meat braised processing by chemical analysis and an electronic tongue system

The aim was to unveil the generation and variation rule of the main taste components in braised broth for 10 quantitative repeated braising cycles. The major taste compounds of three groups (MS, broth cooked with meat and spices; M, broth cooked with meat; and S, broth cooked with spices) were systematically analyzed by the state-of-art chromatography and electronic sensory technology. As braising cycles progressed, contents of free 5'-nucleotides and amino acids were increased in MS and M, while those nucleotides were not detected in S. A significant discrimination of taste in MS and M was revealed by electronic tongue evaluation during the process. As the formation rates (FR) of taste compounds and the transformation rates (TR) of taste compounds to volatile compounds were mainly accounting for the generation and variation of flavor in broth, a hypothesis was proposed to illustrate the whole variation of taste compounds in the process integrally that the ratio of FR/TR dividing the process into three stages, Degradation, Balance, and Accumulation. PRACTICAL APPLICATIONS: The traditional braising process and formula are empirical and extensive, which impede the increase in meat products output. Nowadays, the industry of braising products is facing a problem of standardization and quality control, and needs to carry out scientific and quantitative process improvement efficiently. Therefore, the developed comprehensive approach demonstrates great potential for braised meat broth flavor monitoring and quality control in an objective and holistic manner. It provides data support and new ideas of technology development for quality control in the process of meat braising.

High Altitude Is Beneficial for Antioxidant Components and Sweetness Accumulation of Rabbiteye Blueberry

To better understand the effect of growing location on the phytochemical compounds and sensory properties of blueberry (Vaccinium spp.), here we investigated rabbiteye blueberry 'Brightwell' (Vaccinium ashei cv. 'Brightwell') grown in 10 locations of China. Significant differences in terms of total soluble solids, titratable acidity, flavonoids, phenols, as well as proanthocyanidins and anthocyanins, were found in the fruits (berries) of blueberry plants among the different sampled locations. Furthermore, their sensory properties, which evaluated by the electronic tongue method, also significantly differed among the 10 locations. The content of flavonoids, phenols, proanthocyanidins, and anthocyanins all had significant correlations with sensory properties, except that of aftertaste-astringency. A key finding to emerge was that blueberry plants grown at high altitude locations harbored a high content of total soluble solids, flavonoids, phenols, proanthocyanidins, and anthocyanins along with high scores for the sweetness. These results suggested cultivating blueberry at high altitude can produce fruit that not only possess pronounced beneficial health effects but also good taste.

Historical Evolution and Food Control Achievements of Near Infrared Spectroscopy, Electronic Nose, and Electronic Tongue-Critical Overview

Amid today's stringent regulations and rising consumer awareness, failing to meet quality standards often results in health and financial compromises. In the lookout for solutions, the food industry has seen a surge in high-performing systems all along the production chain. By virtue of their wide-range designs, speed, and real-time data processing, the electronic tongue (E-tongue), electronic nose (E-nose), and near infrared (NIR) spectroscopy have been at the forefront of quality control technologies. The instruments have been used to fingerprint food properties and to control food production from farm-to-fork. Coupled with advanced chemometric tools, these high-throughput yet cost-effective tools have shifted the focus away from lengthy and laborious conventional methods. This special issue paper focuses on the historical overview of the instruments and their role in food quality measurements based on defined food matrices from the Codex General Standards. The instruments have been used to detect, classify, and predict adulteration of dairy products, sweeteners, beverages, fruits and vegetables, meat, and fish products. Multiple physico-chemical and sensory parameters of these foods have also been predicted with the instruments in combination with chemometrics. Their inherent potential for speedy, affordable, and reliable measurements makes them a perfect choice for food control. The high sensitivity of the instruments can sometimes be generally challenging due to the influence of environmental conditions, but mathematical correction techniques exist to combat these challenges.

Comparative analysis of characteristic volatile compounds in Chinese traditional smoked chicken (specialty poultry products) from different regions by headspace-gas chromatography-ion mobility spectrometry

This article presents investigation of the flavor profile on 5 different regional Chinese smoked chicken samples using gas chromatography−ion mobility spectrometry analysis methods. Five batches of samples were obtained over the course of 6 mo. A total of 34 flavor substances were identified in the 5 smoked chicken samples, including 10 aldehydes, 7 alcohols, 4 ketones, 2 hydrocarbons, 3 heterocyclic compounds, 4 esters, 2 ethers, and 2 phenolic compounds. The whole spectral fingerprint visually displayed flavor differences and relations in 5 types of smoked chicken with local characteristics. Moreover, the orthogonal projections to latent structures discriminant analysis model revealed that these samples could be separately classified into 5 groups. Multivariate statistical analysis showed that 20 chemicals with higher Variable Importance for the Projection values were the key contributors to the differences of flavor in these 5 kinds of smoked chicken. N-nonanal, heptanal, n-nonanal, heptanal, furfurol, and hexanal were the main common flavor compounds in the 5 types of Chinese smoked chicken, whereas linalool, alpha-terpineol, 1,8-cineole, and anethole were the main characteristic flavor compounds of Goubangzi chicken (No. 1); gamma-butyrolactone, 2-acetylfuran, 2-methoxyphenol, 2-acetylpyrrole, and limonene were determined as the key flavor compounds of Liaocheng chicken (No. 2); the concentration of octanal and n-nonanal was higher in Tangqiao chicken (No. 3); butyl acetate was the key contributor to the flavor compounds of Jinshan chicken (No. 4). 2-Heptanone and 2-pentylfuran had a high correlation with Zhuozishan chicken (No. 5). The different raw materials and ingredients used, especially the method of preparation and cultural differences, in different regions of the country in China were the main reasons leading to the similarities and differences of volatile compounds in the 5 kinds of Chinese traditional smoked chicken.

Effects of different thermal temperatures on the shelf life and microbial diversity of Dezhou-braised chicken

This work investigated the effects of different thermal temperatures (84 °C for 35 min, 95 °C for 30 min, and 121 °C for 20 min) on the shelf life and microbial diversity of Dezhou-braised chicken. During refrigerated storage at 4 °C, the increase rate of total viable counts, pH and TVB-N value, was lower in 95 °C-treated and 121 °C-sterilized groups, when compared with 84 °C-treated group. Electronic nose revealed that the fresh odor of Dezhou-braised chicken treated by 84 °C and 95 °C could be maintained during storage. Additionally, 95 °C contributed to the maintenance of good texture of chicken. High throughput sequencing showed that Bacillus and Clostridium were only very active in 84 °C-treated samples, but not in 95 °C-treated and 121 °C-sterilized samples. Taken together, 95 °C can be developed as one potential thermal treatment temperature for Dezhou-braised chicken, due to its positive effects on maintaining fresh odor and texture together with extending shelf life while also protecting food safety.

Heterocyclic amines in braised chicken may mainly infiltrate from reused marinade during braising, instead of thermic generation

BACKGROUND

Sauce braised meat products are popular in Asia, although their complicated processing may lead to potential safety risks. Especially, how hazardous compounds are formed during their preparation is still unclear. In the present study, braised chicken breasts, which are a typical Chinese sauce braised meat product, were used to investigate the formation of heterocyclic amines (HCAs) during heat treatment.

RESULTS

Precursor content (creatine and reducing sugar), HCA level and temperature were measured in different parts of the chicken breast at each processing stage. The results obtained showed that the increasing trends of total HCA content in different parts of chicken breast were not the same. Only total HCA content in the skin (4.93 ± 0.80 ng g^-1 ) increased significantly after deep-frying. During braising, total HCA level in the skin was high (12.1-14.3 ng g^-1 ) and relatively stable. However, total HCA content in pectoralis major muscle (3.90-7.40 ng g^-1 ) and pectoralis minor muscle (1.44-5.31 ng g^-1 ) was much lower than in the skin, and increased steadily with braising time.

CONCLUSION

Braising is the main factor which affects HCA level in braised chicken. Combining the results of temperature and precursor content, a possible explanation for the large amount of HCAs in braised chicken is the gradual infiltration from reused marinade, instead of thermic generation. © 2019 Society of Chemical Industry.

Gel properties and flavor characteristics of blended anchovy (Engraulis japonicus) mince and silver carp (Hypophthalmichthys molitrix) surimi

This paper aims to research the gel properties and flavor characteristics of anchovy mince and silver carp surimi blended in different ratios (0/100, 10/90, 20/80, 30/70, 40/60 and 100/0). When the ratios of anchovy mince to silver carp surimi were 10/90 and 20/80, the gel strength of the blended systems increased significantly from 4629.17 g mm to 7568.01 g mm and 6804.22 g mm, respectively. Under these two ratios, the water-holding capacity of the blended systems increased significantly from 56.43% to 71.82% and 69.36%, respectively. In addition, the blended systems formed a highly uniform and dense network structure. At ratios of 0/100, 10/90 and 20/80, the myosin heavy chain was cross-linked, resulting in the formation of macromolecular aggregates. With the increase in anchovy mince content, the brightness and whiteness of the blended systems decreased gradually. When the ratio of anchovy mince to silver carp surimi was 10/90, the sensory evaluation score of the blended system was the highest and the bitterness score the lowest. Under this ratio, the relative contents of esters and aldehydes were the highest, while those of alcohols and ketones were the lowest. In conclusion, the optimum sample formulation contained a 10/90 ratio of anchovy mince to silver carp surimi.

Content of free and protein-binding Nε-carboxymethyllysine and Nε-carboxyethyllysine in different parts of braised chicken

In order to illustrate the levels of advanced glycation end products (AGEs) in Chinese traditional braised chicken, the distribution of free and protein-binding Nε-carboxymethyllysine (CML) and Nε-carboxyethyllysine (CEL) in four parts of processed chicken including chest (X), leg (T), skin (P), and the mixed whole body (M) was investigated. Our results showed that the content of free CML was 1,186.63-1,795.43 ng/g meat and protein-binding CML was 11,693.91-16,122.90 ng/g meat. Differently, the content of free CEL was 24.81-41.62 ng/g meat and protein-binding CEL was 270.11-385.49 ng/g meat. It was found that the total contents of CML were 31.5-56.8 folds higher than those of CEL. Protein-binding AGEs (CML + CEL) were 6.6-9.9 times higher than those of free AGEs (CML + CEL). Pearson's correlation of AGEs and oxidation in four parts of braised chicken were also investigated, and the results showed that oxidation had a significant effect on levels of CEL; especially, the protein carbonyl was negatively correlated with free CEL (p < .05). TBARs value was significantly positively correlated with protein-binding and total CEL (p < .01). In conclusion, our findings are important for better understanding of the AGEs formation in braised meat.

Emerging trends of advanced sensor based instruments for meat, poultry and fish quality- a review

Meat and fish chemical composition and sensory attributes are markers of quality that require innovative assessment methods as existing ones are rather technical, laborious, and expensive. Emerging trends of advanced technology instruments have been lauded in the pharmaceutical, cosmetic and food industries for their high sensitivity, customizability, rapidness and affordability. Common among these, are the electronic tongue (e-tongue) and electronic nose (e-nose) but their use for meat and fish quality, remains scanty and scattered. This paper aims to systematically discuss the developing trends, principles and the recent use of e-tongue and e-nose for quality measurements in fish and meat. From over 90 research papers, it was observed that an arsenal of chemometric tools have been pivotal in applying these instruments for rapid quantitative, qualitative and predictive analysis of some physical properties, chemical properties, storability and the authentication of meat and fish. Both instruments require no reagent (waste free analytical procedure) and have been lauded for precision and*accuracy but e-nose may be better suited for meat and fish assessments. Unlike the e-tongue, e-nose requires no liquid sample preparation and portable versions are promising for rapid remote analysis of meat and fish samples that can save cost on transferring carcass to laboratories.

Fatty Acid Content, Flavor Compounds, and Sensory Quality of Pork Loin as Affected by Dietary Supplementation with l-arginine and Glutamic Acid

To investigate the effect of functional amino acid on meat flavor and eating quality, 60 growing-finishing pigs (Duroc × Large White × Landrace) were dietarily supplemented with or without 1.0% l-arginine, glutamic acid, or l-arginine plus glutamic acid for 2 months. After animals were slaughtered, the muscle fatty acid profile, flavor compounds, and meat sensory quality were comparatively investigated. The results showed that dietary supplementation with arginine, glutamic acid, or arginine plus glutamic acid had little effect on free amino acids, no effect on 5'-nucleotides and meat sensory taste traits, but supplementation with arginine plus glutamic acid significantly increased (P < 0.05) fat accumulation and fatty acid content in muscle, increased (P < 0.05) the formation of multiple fatty acid oxidation-derived volatile compounds, and improved the tenderness, juiciness, and overall eating quality of meat. This study revealed that dietary supplementation with 1.0% l-arginine and glutamic acid could be used to improve meat eating quality in pork production.

A predictive model for the evaluation of flavor attributes of raw and cooked beef based on sensor array analyses

There are currently no standardized objective measures to evaluate beef flavor attributes, especially the comparison between raw beef and cooked beef. Beef flavor attribute is one of the most significant parameters for consumers. This study described a predictive model using a 12-ion-sensor array and sensory properties to evaluate beef flavor attributes based on potential. Then the number of sensors was reduced to six via variance of analysis, and these six sensors were reserved with the saturated calomel reference electrode to constitute a new sensor array. Sensitive flavors of each sensor were selected through multiple comparative analysis. Results showed that the accuracy rate of classifying five basic flavors (acidity, sweetness, bitterness, saltiness, freshness) using the new sensor array was 100%. The processing methods used were based on multivariate statistical methods done with the cluster analysis (CA). Results were compared to sensory evaluation using genetic algorithm (GA). From GA, the accuracy rates of raw and cooked beef were 85.0% and 90.0%, which was consistent with the sensory analysis results. Moreover, reducing the number of sensors could decrease the data dimensionality and detection time. Also raw beef instead of cooked beef could be used in flavor attributes evaluation. This model could become an important method for evaluating beef flavor attributes repeatedly and objectively.