A Comparison between the Egg Yolk Flavor of Indigenous 2 Breeds and Commercial Laying Hens Based on Sensory Evaluation, Artificial Sensors, and GC-MS

Transparent mechanism of salted egg (white) hierarchically and synergistically driven by NaCl, NaOH and thermal treatment: Based on empirical data and molecular simulation

Currently, it is a challenge that the yolk in salted preserved egg tends to preserved egg yolk due to extreme NaOH treatment. Therefore, NaCl, NaOH and thermal were successfully used to prepare a new translucent salted quail egg (T-SQE), which combined advantages of preserved egg white with transparent appearance and salted egg yolk with unique texture and odour. Moreover, transparency of opaque gel (Transmittance: 0.09 %) subjected to NaCl and thermal was demonstrated to be improved under the synergistic effect of NaOH (8.55 %) via empirical data and molecular simulation. The disordered and dense network in opaque T-SQE induced by NaCl and thermal tended to form an ordered, porous and transparent structure in presence of NaOH, with more immobilized water that was poorly bonded to protein, larger radius of gyration and lower hydrophobic interaction. This research provides new insight into understanding the influence of hierarchy and synergism on transparency of egg products.

Characterization and Evaluation of Taihe Black-Boned Silky Fowl Eggs Based on Physical Properties, Nutritive Values, and Flavor Profiles

Taihe black-boned silky fowl (TS) is a native chicken breed in China with more than 2000 years of history. The present study aimed to characterize and evaluate the physical, nutritional, and flavor properties of TS eggs with a comparison to two other commercial breeds. Eggs from TS (n = 60) crossbred black-boned silky fowl (CB, n = 60) and Hy-line Brown (HL, n = 60) were used for physicochemical analysis. The evaluation system was divided into four parts based on nutrient and flavor profiles: protein and amino acids, lipids and fatty acids, mineral elements, and flavor-related amino acids and volatile compounds. Results showed that TS eggs were typically associated with the lowest egg weight and the highest yolk color, as compared with CB and HL eggs. No differences were found in crude protein, crude fat, triglycerides, and cholesterol content between eggs from the different breeds, but these eggs were distinct in terms of the amino acid, fatty acid, and volatile flavor compound profiles. Moreover, the differences in amino acid and fatty acid profiles might contribute to the specific flavor of TS eggs. Evaluation results indicated that TS egg whites may be suitable as a protein source for premature infants and young children under three years old and TS egg yolks could be considered a beneficial dietary lipid source due to their potential anti-cardiovascular properties. Additionally, TS whole eggs could serve as a valuable source of selenium (Se), molybdenum (Mo), zinc (Zn), and phosphorus (P) for adults aged 18 to 65. However, TS and CB eggs showed inferior Haugh units, eggshell quality, and essential amino acid compositions for older children, adolescents, and adults. These findings provide a better insight into the health benefits of TS eggs and contribute to the breeding and nutrition regulation of TS breeds.

Testing adulterated liquid-egg: developing rapid detection techniques based on colorimetry, electrochemistry, and interfacial fingerprinting

To develop rapid detection techniques for liquid eggs' adulteration, three types of adulterations were considered: water dilution, manipulation of yolk ratio in whole egg, and blending different varieties of egg white or yolk. Objective: Establish detection techniques utilizing colorimetry, electrochemistry, and interfacial fingerprinting for these adulterations, respectively. Results: Colorimetry allows for detection (1 min·sample-1) of water dilution through linear (R2 ≥ 0.984) and exponential fitting (R2 ≥ 0.992); Electrochemistry enables detection (6 min·sample-1, R2 ≥ 0.979) of the adulteration of yolk ratio in whole egg; Interfacial fingerprinting technique effectively detects (detection duration: 10 min·sample-1, detection limit: 1.0-10.0 wt%) the adulteration of different varieties of egg white. Subsequently, through 3D-fluorescence microscopy (interface height variation: 22.49-573.45 μm), interfacial tension variation (65.54-35.48 mN·m-1), contact angle variation (89.7°-32.9°), particle size range (free water: 0.94-14.29 μm; protein aggregation: 6.57-10.76 μm), and etc., interfacial fingerprinting mechanism was elucidated. This research contributes novel insights into the detection of adulteration in liquid eggs.

Novel Insights into the Effects of Different Cooking Methods on Salted Egg Yolks: Physicochemical and Sensory Analysis

In this study, the flavor characteristics and physicochemical properties of salted egg yolk (SEY) under different cooking methods (steaming/baking/microwaving) were investigated. The microwave-treated SEY exhibited the highest levels of salt content, cooking loss, lightness, and b* value, as well as the highest content of flavor amino acids. A total of 31, 27, and 29 volatile compounds were detected after steaming, baking, and microwave treatments, respectively, covering 10 chemical families. The partial least squares discriminant analysis confirmed that 21 compounds, including octanol, pyrazine, 2-pentyl-furan, and 1-octen-3-ol, were the key volatile compounds affecting the classification of SEY aroma. The electronic nose revealed a sharp distinction in the overall flavor profile of SEY with varying heat treatments. However, no dramatic differences were observed in terms of fatty acid composition. Microwave treatment was identified as presenting a promising approach for enhancing the aroma profile of SEY. These findings contribute novel insights into flavor evaluation and the development of egg products as ingredients for thermal processing.

Evaluation of fifteen processing methods of hellgrammites based on the flavor characteristics

To investigate suitable processing methods for improve the flavor while maintaining quality, hellgrammites were subjected to fifteen different processing methods. The samples were tested by sensory evaluation and were analyzed using HS-SPME-GC-MS. The sensory evaluation revealed that five methods for head and chest removal, three wine-fried methods, and three vinegar-roasting methods significantly reduced the levels of hexanal (3129.05 ± 45.77 μg/kg) and heptanal (436.72 ± 7.42 μg/kg), compounds responsible for fishy and earthy flavors, compared to raw samples. The latter two methods exhibited increased aroma flavor. PCA and OPLS-DA analyses suggested that acids, alcohols, and esters played a crucial role in flavor modification. Notably, vinegar-roasting methods demonstrated the highest acid content and had a substantial impact on volatile compounds. Additionally, boiling methods effectively reduced the levels of hazardous compounds, such as toluene and 1,3-Dimethyl-benzene. However, other methods did not exhibit similar efficacy in reducing hazardous compounds. The accumulation of hazardous compounds showed a decreasing trend in the whole insect, head removal, and head and chest removal groups. Moreover, the relative odor activity value consistently identified aldehyde compounds, including hexanal and heptanal, as the main contributors to aroma. Overall, boiling and head and chest removal procedures were suggested as precautionary measures during the initial processing of hellgrammites-based food products. The vinegar-roasting and wine-fried methods could be employed to impart desired flavors, aligning with consumers' preferences. These findings lay the foundation for standardizing processing techniques and ensuring the quality control of products derived from hellgrammites.

Comparative characterization of flavor precursors and volatiles of Taihe black-boned silky fowl and Hy-line Brown yolks using multiomics and GC-O-MS-based volatilomics

Eggs are nutritious and highly valued by consumers. However, egg flavor varies greatly among different hen breeds. The present study used gas chromatography-olfactometry-mass spectrometry-based volatilomics to identify and compare volatile compounds in Taihe black-boned silky fowl (TS) and Hy-line Brown (HL) egg yolks. In addition, the relationships between the levels of different metabolites and lipids and flavor-associated differences were investigated using multiomics. Twenty-eight odorants in total were identified; among them, the levels of 3-methyl-butanal, 1-octen-3-ol, 2-pentylfuran, and (E, E)-2,4-decadienal differed significantly (P < 0.05) between TS and HL egg yolks. The difference in flavor compounds results in TS egg yolks having a stronger overall odor and flavor and a higher acceptance level than HL egg yolks. Metabolomic analysis revealed that 112 metabolites in the egg yolks were significantly different between the two breeds. Furthermore, these different metabolites in the egg yolks of both breeds were significantly enriched in phenylalanine, tyrosine, and tryptophan biosynthesis pathways and phenylalanine metabolism, alanine, aspartate, and glutamate metabolism pathways (P < 0.05), as identified by both metabolite set enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses. Lipidomic analysis revealed significant differences in the lipid subclasses, lipid molecules, and fatty acid profiles between the egg yolks from the two breeds. As a result, 48 lipid molecules had variable influence in projection values > 1 based on the partial least squares regression model, which may play a role in the differences in aroma characteristics between the two breeds through oxidative degradation of fatty acids. Our study revealed the metabolite, lipid, and volatility profiles of TS and HL egg yolks and may provide an important basis for improving egg flavor to satisfy various consumer preferences.