Evaluation of the flavour properties of cooked chicken drumsticks as affected by sugar smoking times using an electronic nose, electronic tongue, and HS-SPME/GC-MS

Flavor Differences of Edible Parts of Grass Carp between Jingpo Lake and Commercial Market

This study investigated the flavor differences among three individual parts (abdomen, back, and tail) of Jingpo Lake grass carp (JPGC) and commercial grass carp (CGC). The growing environment and fish parts influenced the volatile compounds of the fish. The highest total contents of alcohols and ethers were found in the back of JPGC (p < 0.05). The combination of an electronic tongue and electronic nose (E-nose) could effectively distinguish the flavor differences between the different parts of JPGC and CGC by principal component analysis. Both the content of total free amino acids (FAAs) and content of amino acids contributing to the sweet and fresh flavors were higher in JPGC than CGC (p < 0.05). Among the ATP-associated products, the inosine 5’-monophosphate (IMP) contents of the back and tail of JPGC were higher (p < 0.05), but the abdomen content was lower (p > 0.05) than the respective contents in the corresponding parts of CGC. Sensory evaluation shows that JPGC had a better texture, odor, and taste, compared to CGC. Correlation analysis showed that the E-nose data and FAAs were highly correlated with the content of alcohols, aldehydes, and ethers. This study showed that the flavors of the different parts of JPGC differed significantly from those of CGC.

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.

Application of Digital Olfaction for Table Olive Industry

The International Olive Council (IOC) established that olives must be free of odors, off-flavors, and absent of abnormal ongoing alterations or fermentations. The use of electronic devices could help when classifying defects in a fast, non-destructive, cheap, and environmentally friendly way. For all of that, table olives were evaluated according to IOC regulation in order to classify the defect predominant perceiving (DPP) of the table olives and their intensity. Abnormal fermentation defects of Spanish-style table olives were assessed previously by an IOC-validated tasting panel. 'Zapateria', 'Putrid', and 'Butyric' were the defects found at different concentrations. Different volatile compounds were identified by gas chromatography in altered table olives. The same samples were measured with an electronic nose device (E-nose). E-nose data combined with chemometrics algorithms, such as PCA and PLS-DA, were able to successfully discriminate between healthy and non-healthy table olives, being this last one also separated between the first and second categories. Volatile compounds obtained with gas chromatography could be related to the E-nose measuring and sensory analysis, being capable of matching the different defects with their correspondents' volatile compounds.

The Effect of Hot-Air Dried Lentinula edodes on the Quality and Oranoleptic Properties of Rolled-Dumplings

The effect of hot-air dried Lentinula edodes pileus (DLE) on the quality and organoleptic properties of rolled-dumplings was evaluated. DLE was prepared by drying at 60°C for 24 h and added (Non, 7%, and 9%) to rolled-dumplings. The proximate composition, pH, color (CIE L*, a*, b*), and cooking yield were analyzed. Texture profile analysis, electronic-nose (e-nose), electronic-tongue (e-tongue), and organoleptic evaluation were also conducted. The cooking yield of dumplings with 9% DLE was significantly lower than that of the congeners without DLE, whereas 7% DLE did not lead to significant differences compared without DLE. With increasing DLE addition, the pH and lightness of the dumplings decreased significantly, whereas the redness tended to increase. The texture profile was significantly higher for the dumplings with DLE compared to those without DLE. E-nose analysis confirmed that DLE addition led to the positive odors (methanethiol: meaty, sulfurous; 3-methylbutanal: malty, toasted) and the negative odors (trimethylamine: ammoniacal; acetic acid: acidic, sour). E-tongue analysis showed that DLE addition decreased the intensity of the sourness and increased the intensity of the saltiness and umami of rolled-dumplings. DLE addition improved the overall organoleptic properties, but 9% DLE can be recognized as a foreign substance in organoleptic acceptance. Consequently, DLE has the potential to serve as a flavor and odor enhancer for rolled-dumplings, and the addition of DLE can positively improve consumer acceptance by improving the quality and organoleptic properties.

Micronized cold-pressed hemp seed cake could potentially replace 50% of the phosphates in frankfurters

Present study aimed to investigate the concentration effect of micronized cold-pressed hemp seed cake (MCPHSC) on the quality profiles and sensorial attributes of 50% phosphates reduced frankfurters. The results showed that MCPHSC could be used as an ideal phosphates replacer for obviously decreasing the cooking loss and promoting textural and gel properties of reduced-phosphates frankfurters (P < 0.05), which was verified by scanning electron microscopy. Moreover, the incorporation of MCPHSC could significantly inhibit the occurrence of lipid oxidation of reduced-phosphates frankfurters during storage in a dose-dependent manner (P < 0.05). Additionally, replacing 50% phosphates with 2% (w/w) MCPHSC was found to possess the best optimal replacement effect to enhance the quality profiles of reduced-phosphates frankfurters (P < 0.05). However, a higher amount of MCPHSC had a negative effect on the sensorial evaluations of the reduced-phosphates frankfurters. Our results suggested that the addition of MCPHSC could be applied as a practical way for improving the quality defects of reduced-phosphates frankfurters.

The Improvement of Sensory and Bioactive Properties of Yogurt with the Introduction of Tartary Buckwheat

The incorporation of cereals in yogurt has recently gained increasing consumer approval, for its high nutritional value and health benefits, all over the world. Following this emerging trend, Tartary buckwheat (TB) was supplemented into yogurt as a natural functional ingredient in order to develop a yogurt with enhanced product characteristics and consumer acceptability. The impact of TB addition on physicochemical properties (pH, acidity, apparent viscosity, etc.) and the viability of lactic acid bacteria in yogurt was investigated. It is found that the TB introduction can reduce the pH, increase the acidity and apparent viscosity, and also greatly boost the bioactivities of yogurt. Response surface analysis demonstrated that yogurt with 8 g of TB, 10 g of sugar, and a fermentation duration of 5 h had the highest overall acceptability, and these cultural conditions were chosen as the best. Furthermore, the TB-added yogurt had not only a better sensory and aroma profile, but also good prospective health advantages when compared to regular yogurt. Our research shows that adding TB to yogurt has a significant positive impact on both overall quality and sensory characteristics, making a compelling case for using TB yogurt and developing new fermented dairy products.

Differentiation of Penaeus vannamei from different thermal processing methods in physico-chemical, flavor and sensory characteristics

Differentiation in physico-chemical, flavor and sensory characteristics of shrimps (Penaeus vannamei) after direct roasting (DR, 200 °C), boiling (100 °C/2 min) + roasting (BR), steaming (100 °C/2 min) + roasting (SR) and microwaving (280 W/2 min) + roasting (MR) was investigated. BR, SR, and MR endowed shrimps with better texture to varying degrees and significantly (P < 0.05) increased lightness when compared to DR, which closely related to their different water status. High correlations between nuclear magnetic resonance data and quality properties were found by partial-least-squares regression (PLSR). Shrimps possessed by SR significantly (P < 0.05) increased the proportion of sweet amino acids (63.89 ± 0.92%), with superior umami and richness detected by electronic tongue. Compared with DR, both SR and MR endowed shrimps with richer ester, while BR endowed shrimps with richer hydrocarbons. Roasting combined with other thermal processing would favor improving the quality of shrimp products.

Progress of Research on the Application of Nanoelectronic Smelling in the Field of Food

In the past 20 years, the development of an artificial olfactory system has made great progress and improvements. In recent years, as a new type of sensor, nanoelectronic smelling has been widely used in the food and drug industry because of its advantages of accurate sensitivity and good selectivity. This paper reviews the latest applications and progress of nanoelectronic smelling in animal-, plant-, and microbial-based foods. This includes an analysis of the status of nanoelectronic smelling in animal-based foods, an analysis of its harmful composition in plant-based foods, and an analysis of the microorganism quantity in microbial-based foods. We also conduct a flavor component analysis and an assessment of the advantages of nanoelectronic smelling. On this basis, the principles and structures of nanoelectronic smelling are also analyzed. Finally, the limitations and challenges of nanoelectronic smelling are summarized, and the future development of nanoelectronic smelling is proposed.

Electronic nose application for the discrimination of sterilization treatments applied to Californian-style black olive varieties

BACKGROUND

Olive oil continues to be the main destination for olives. The production of table olives is increasing. 'Californian-style' processes are among the most frequently employed to produce oxidized olives. Sensory evaluation requires the development of an instrumental detection method that can be used as an adjunct to traditional tasting panels.

RESULTS

An electronic nose (E-nose) was used to classify two varieties of olives following exposure to different sterilization. Principal component analysis (PCA) revealed that both varieties had different volatile profiles. Sensory panel evaluations were similar for both. Partial least squares-discriminant analysis (PLS-DA) obtained from the E-nose was able to separate the two varieties and explained 82% of total variance. Moreover, volatile profiles correctly classified olives according to sterilization times recorded up to 121 °C . The only exception was at F₀  ≥ 22 min, at which a plot of PCA outcomes failed to differentiate scores. E-nose data showed similar results to those produced from the volatile analysis when grouping samples were sterilized to F₀  ≥ 18 min, at the same time distinguishing these samples from those subjected to less intense thermal treatments. A partial least squares (PLS) chemometric approach was evaluated for quantifying important olive quality parameters. With regards to validation parameters, R P 2 pertaining to perceived defect was 0.88, whilst R P 2 pertaining to overall assessment was 0.78.

CONCLUSIONS

E-nose offers a fast, inexpensive and non-destructive method for discriminating between varieties and thermal treatments up to a point at which cooking defects are highly similar (from F₀  = 18 onwards). © 2021 Society of Chemical Industry.

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.

Flavour Compensation Role of Yeast Strains in Reduced-Salt Dry Sausages: Taste and Odour Profiles

The effects of different yeast strains including Pichia kudriavzevii, Torulaspora delbrueckii, and Debaryomyces hansenii on the taste and odour profiles of reduced-salt dry sausages were explored. Inoculation of P. kudriavzevii and D. hansenii compensated for the lack of saltiness and umami tastes of reduced-salt sausages. Furthermore, inoculation of P. kudriavzevii and T. delbrueckii resulted in an odour profile in the reduced-salt dry sausages that was similar to traditional dry sausages. According to the volatile analysis, the contents of certain alcohols, acids, esters and terpenes were higher in the inoculated sausages. Finally, the sensory evaluation indicated that the inoculation of P. kudriavzevii and D. hansenii contributed positively to the aroma and saltiness of reduced-salt dry sausages. In conclusion, P. kudriavzevii and D. hansenii can be employed as effective starter cultures to compensate for the flavour deficiencies of reduced-salt dry sausages.

Effects of Modified Atmosphere Packaging with Various CO2 Concentrations on the Bacterial Community and Shelf-Life of Smoked Chicken Legs

The effects of modified atmosphere packaging (MAP) with various CO₂ concentrations on the bacterial community and shelf-life of smoked chicken legs during 25 d of storage at 4 °C were evaluated herein. Four treatments were stored in pallets (PAL) and MAP under 20% (M20), 60% (M60), and 100% (M100) CO₂, respectively. The results indicated that the MAP treatments provided the legs with higher redness and hardness and lower yellowness, luminance, and lipid oxidation, compared with the PAL treatment. In addition, the MAP treatments effectively inhibited the growth of viable bacteria, delayed bacterial spoilage, and extended the shelf-life of the samples. The M60 and M100 treatments had a better inhibition effect on bacteria. In terms of bacterial community, Carnobacterium, Pseudomonas, Brochothrix, and Lactococcus were the most predominant genera in the 25 d-stored MAP samples, with Carnobacterium maltaromaticum, Pseudomonas fragi, Shewanella baltica, and Lactococcus piscium being the dominant species. However, while the inhibition effects of the M60 and M100 treatments on the bacterial community at Day 25 were similar, the outer package of the M100 treatment collapsed. Overall, the M60 treatment may be a promising approach to improving the quality and extending the shelf-life of smoked chicken legs.

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.

Effects of ultrasound pretreatment on the quality, nutrients and volatile compounds of dry-cured yak meat

The objective of the present study was to assess the effects of ultrasound pretreatment on the quality of dry-cured yak meat. The ultrasonic power with 0, 200, 300 and 400 W (ultrasonic frequency of 20 kHz) were used to assist processing of dry-cured yak meat. The meat quality, nutrient substances, sensory quality, electronic nose, electronic tongue and volatile compounds of dry-cured yak meat were determined. The results indicated that the moisture content and hardness value of ultrasonic treatment group was significantly lower compared to the control group (P < 0.05). Ultrasonic treatment increased the value of b*, and decreased the value of L*, a*, pH, chewiness, melting temperature and enthalpy. Springiness value significantly increased from control group to 300 W of ultrasonic power group. Shear force significantly decreased with the increase of ultrasonic power (P < 0.05). Ultrasonic treatment had no effect on the TVB-N content, but it could increase the TBARS content. Ultrasonic treatment could significantly increase the essential FAA (EFAA) and total FAA (P < 0.05). In addition, the saturated fatty acid (SFA) content significantly increased with the increase of ultrasonic power (P < 0.05). Ultrasound treatment negatively affected the meat's color, smell, and taste but increased its tenderness and the overall acceptability. It also significantly increased alcohols and aldehydes contents (P < 0.05), which were consistent with the measurement of electronic nose and electronic tongue. The results demonstrated that the the appropriate ultrasonic power assisted in the processing improves quality of dry-cured yak meat, particularly for the power of 300 W.

Analysis of the volatile compounds in Fuliji roast chicken during processing and storage based on GC-IMS

To investigate the flavor changes of Fuliji roast chicken during processing and storage, the volatile organic compounds (VOCs) during processing (fresh, fried, stewed and sterilized) and storage (1 month, 2 months and 4 months) were determined by gas chromatography ion mobility spectrometry (GC-IMS). A total of 47 kinds of VOCs were identified across seven sampling stages, including aldehydes, hydrocarbons, alcohols, ketones, esters, ethers and heterocyclic compounds. More diverse range of aldehydes, alcohols, ketones and esters have been detected compared to acids, ethers and heterocyclic substances. Fingerprints directly reflect the pattern of VOCs at different stages of growth and decay, revealing that frying and stewing are key processes in flavor formation, and that sterilization and storage processes lead to flavor loss in Fuliji roast chicken. Hexanal, nonanal, octanal, 2-heptanone, 3-octanol, 1-octene-3-alcohol, 1-pentanol and ethyl acetate were mainly generated during the frying process. Benzaldehyde, nonanal, octanal, methyl-5-hepten-2-one, 2-methyl-3-heptanone, 1,8-Cineole, linalool, butyl acetate, ethyl propionate, ethyl acetate, coumarin, 2-furfuryl methyl disulfide and 2-pentyl furan were mainly generated during the stewing process. After sterilization, the content of octanal-D, 2-heptanone-D, 2-Methyl-3-heptanone, pentan-1-ol-D decreased, resulting in the reduction of aroma, lemon flavor and oil flavor of Fuliji roast chicken. Seven flavor markers, including hexanal-D, nonanal-M, octanal-M, heptanal-D, acetone, 3-octanol and ethyl acetate-D, were identified in the evolution of the aroma profile of Fuliji roast chicken.

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GC-IMS profiles of flavor components in poultry product processing line.

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47 kinds of volatile substances were identified by GC-IMS.

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Frying and stewing were the key processes of flavor formation.

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Flavor markers in the evolution of aroma characteristics of Fuliji roast chicken were determined.

Comprehensive Evaluation of Flavor in Charcoal and Electric-Roasted Tamarix Lamb by HS-SPME/GC-MS Combined with Electronic Tongue and Electronic Nose

To prevent the pollution generated during charcoal roasting of tamarix lamb, environmental-friendly electric is gradually applied in meat processing. The profile and formation of flavor in roasted tamarix lamb were evaluated using HS-SPME/GC-MS combined with E-nose/-tongue. Results indicated that charcoal-roasted tamarix lamb exhibited the higher taste of umami and sourness in E-tongue and had higher contents of alcohols, aldehydes, ketones, alkanes, and aromatics in E-nose, while the electric ones exhibited the higher taste of sweetness and bitterness and had higher contents of nitrogen oxides, terpenes, aromatics, and organic sulfur. Compared with charcoal, application of the electric significantly decreased the numbers of key volatile compounds with VIP > 1 (markers) and the contents of most markers.

Establish intelligent detection system to evaluate the sugar smoking of chicken thighs

The objective of this study was to establish a standardized color detection method to achieve low-cost, rapid, nonintrusive and accurate characterization of the color change of smoked chicken thighs during the smoking process. This study was based on machine vision technology using the Mean algorithm, K-means algorithm and K-means algorithm + image noise reduction algorithm to establish 3 colorimetric cards for the color of sugar-smoked chicken thighs. The accuracy of the 3 colorimetric cards was verified by the K-medoids algorithm and sensory analysis, respectively. Results showed that all 3 colorimetric cards had significant color gradient changes. From the K-medoids algorithm, the accuracy of the colorimetric card produced by the Mean algorithm, K-means algorithm and K-means algorithm + image noise reduction algorithm was 87.2, 95.1, and 96.7%, respectively. Meanwhile, the verification results of the sensory analysis showed that the accuracy of the Mean algorithm, K-means algorithm and K-means algorithm + image noise reduction algorithm colorimetric card was 69.4, 80.9, and 79.2%, respectively. A comparative analysis found that the colorimetric cards produced by the K-means algorithm and K-means algorithm + image noise reduction have excellent accuracy. These 2 colorimetric cards could become a suitable method for rapid, low-cost, and accurate online color monitoring of smoked chicken.

HS-SPME-GC-MS and Electronic Nose Reveal Differences in the Volatile Profiles of Hedychium Flowers

Floral fragrance is one of the most important characteristics of ornamental plants and plays a pivotal role in plant lifespan such as pollinator attraction, pest repelling, and protection against abiotic and biotic stresses. However, the precise determination of floral fragrance is limited. In the present study, the floral volatile compounds of six Hedychium accessions exhibiting from faint to highly fragrant were comparatively analyzed via gas chromatography-mass spectrometry (GC-MS) and Electronic nose (E-nose). A total of 42 volatile compounds were identified through GC-MS analysis, including monoterpenoids (18 compounds), sesquiterpenoids (12), benzenoids/phenylpropanoids (8), fatty acid derivatives (2), and others (2). In Hedychium coronarium 'ZS', H. forrestii 'Gaoling', H. 'Jin', H. 'Caixia', and H. 'Zhaoxia', monoterpenoids were abundant, while sesquiterpenoids were found in large quantities in H. coccineum 'KMH'. Hierarchical clustering analysis (HCA) divided the 42 volatile compounds into four different groups (I, II, III, IV), and Spearman correlation analysis showed these compounds to have different degrees of correlation. The E-nose was able to group the different accessions in the principal component analysis (PCA) corresponding to scent intensity. Furthermore, the pattern-recognition findings confirmed that the E-nose data validated the GC-MS results. The partial least squares (PLS) analysis between floral volatile compounds and sensors suggested that specific sensors were highly sensitive to terpenoids. In short, the E-nose is proficient in discriminating Hedychium accessions of different volatile profiles in both quantitative and qualitative aspects, offering an accurate and rapid reference technique for future applications.

E-Nose Discrimination of Abnormal Fermentations in Spanish-Style Green Olives

Current legislation in Spain indicates that table olives must be free of off-odors and off-flavors and without symptoms of ongoing alteration or abnormal fermentations. In this regard, the International Olive Council (IOC) has developed a protocol for the sensory classification of table olives according to the intensity of the predominantly perceived defect (PPD). An electronic nose (e-nose) was used to assess the abnormal fermentation defects of Spanish-style table olives that were previously classified by a tasting panel according to the IOC protocol, namely zapateria, butyric, putrid, and musty or humidity. When olives with different defects were mixed, the putrid defect had the greatest sensory impact on the others, while the butyric defect had the least sensory dominance. A total of 49 volatile compounds were identified by gas chromatography, and each defect was characterized by a specific profile. The e-nose data were analyzed using principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA). The different defects were clearly separated from each other and from the control treatment, independently of PPD intensity. Moreover, the e-nose differentiated control olives from table olives with combined sensory defects despite the dilution effect resulting from the combination. These results demonstrate that e-nose can be used as an olfactory sensor for the organoleptic classification of table olives and can successfully support the tasting panel.

Comparison of Sensory Qualities in Eggs from Three Breeds Based on Electronic Sensory Evaluations

The present study was conducted on three commercial laying breeder strains to evaluate differences of sensory qualities, including texture, smell, and taste parameters. A total of 140 eggs for each breed were acquired from Beinong No.2 (B) laying hens, Hy-Line Brown (H) laying hens, and Wuhei (W) laying hens. Sensory qualities of egg yolks and albumen from three breeds were detected and discriminated based on different algorithms. Texture profile analysis (TPA) showed that the eggs from three breeds had no differences in hardness, adhesiveness, springiness, and chewiness other than cohesiveness. The smell profiles measured by electronic nose illustrated that differences existed in all 10 sensors for albumen and 8 sensors for yolks. The taste profiles measured by electronic tongue found that the main difference of egg yolks and albumen existed in bitterness and astringency. Principal component analysis (PCA) successfully showed grouping of three breeds based on electronic nose data and failed in grouping based on electronic tongue data. Based on electronic nose data, linear discriminant analysis (LDA), fine k-nearest neighbor (KNN) and linear support vector machine (SVM) were performed to discriminate yolks, albumen, and the whole eggs with 100% classification accuracy. While based on electronic tongue data, the best classification accuracy was 96.7% for yolks by LDA and fine tree, 88.9% for albumen by LDA, and 87.5% for the whole eggs by fine KNN. The experiment results showed that three breeds’ eggs had main differences in smells and could be successfully discriminated by LDA, fine KNN, and linear SVM algorithms based on electronic nose.

Evaluation of flavor characteristics of bacon smoked with different woodchips by HS-SPME-GC-MS combined with an electronic tongue and electronic nose

This study investigated the effects of different woodchip types (beech, oak, pear, and apple) on the volatile compounds and sensory characteristics of smoked bacon. The volatile compounds were influenced by woodchip types and the total content of ketones and phenols in pear-smoked bacon were higher than in bacon smoked with other woodchips (P < 0.05). The E-tongue combined with E-nose can effectively distinguish the difference in the flavor of bacon smoked with different woodchip types by the signal intensities. Sensory analysis showed that smoking increased bacon's redness, saltiness, and smoky flavor compared with the control (unsmoked bacon) (P < 0.05) and it had little impact on off-odor (P > 0.05). Correlation analysis showed that the E-nose and E-tongue data were highly correlated with contents of alcohols, aldehydes, and ketones. This study revealed that the different smoked materials greatly influenced the flavor and sensory properties of bacon.

Comprehensive Evaluation of Volatile and Nonvolatile Compounds in Oyster Cuts of Roasted Lamb at Different Processing Stages Using Traditional Nang Roasting

Nang roasting is a traditional lamb processing method in Xinjiang (China) with a history of thousands of years. This study comprehensively evaluated the volatile and nonvolatile compounds of oyster cuts of roasted lamb at different processing stages of Nang roasting using gas chromatography mass spectrometry and amino acid automatic analyzer, respectively. Results indicated that aldehydes were the dominant profiles of volatile compounds, and hexanal, nonanal, octanal, (E)-2-nonenal, (E, E)-2,4-decadienal, (E, E)-2,4-nonadienal and 1-octen-3-ol were the key volatile compounds or aroma contributors to roasted oyster cuts. Isoamylol and 3-hydroxy-2-butanone could differentiate fresh and marinated oyster cuts from roasted ones; (E)-2-nonenal, (E, E)-2,4-decadienal, 1-octen-3-ol, hexanal, octanal, nonanal and (E, E)-2,4-nonadienal could differentiate Nang roasted oyster cuts of 60 min from those of 15, 30 and 45 min. Umami amino acids and sweet amino acids are the dominant profiles of nonvolatile compounds; glutamic acid, alanine and 5′-IMP were the key free amino acids or taste contributors to roasted oyster cuts. Glutamic acid, alanine and 5′-IMP could differentiate fresh and marinated oyster cuts from roasted samples. This work provided theoretical support for the control of flavor attributes of roasted lamb with traditional Nang roasting.

Change Regularity of Taste and the Performance of Endogenous Proteases in Shrimp (Penaens vannamei) Head during Autolysis

This study evaluated the food safety and proximate composition of shrimp head (SH). Potentially toxic elements in SH were below European Union legislation limits. SH had a high content of tasting amino acids (sweet and umami amino acids was 57%) and a high content of functional amino acids (essential amino acids was 37%). Moreover, the changes of flavor and key umami molecules in SH were studied by sensory evaluation, electronic tongue, electronic nose, automated amino acid analyzer, and high performance liquid chromatography (HPLC). The results showed that the significant difference of flavor in SH happened during autolysis. SH with autolysis had the best umami taste at 6 h, which may result from the synergistic work of free amino acids and nucleotide related compounds. Additionally, the performance of endogenous proteases in SH was investigated to efficiently analyze autolysis. The optimum pH and temperature of endogenous proteases in SH were 7.5 and 50 °C, respectively. The autolysis of SH depends on two endogenous proteases (~50 kDa and ~75 kDa). These results suggest that the formation of flavor in SH during autolysis can be controlled, which could provide guidance for SH recycle. SH could consider as one of the food materials for producing condiments.