The effects and reasons of perilla juice (PJ) and ginger juice (GJ) on the reduction of \"warmed-over flavor\" (WOF) in surimi gels were revealed by detecting odor profiles and protein and lipid oxidation degrees of surimi gels, concentrations and odor activity values (OAVs) of WOF compounds. Adding PJ and GJ to surimi gels significantly reduced the WOF and improved the fish fragrance odor, but sodium ascorbate (SA) only weakened the WOF. The (E,E)-2,4-heptadienal\'s OAVs in the PJ and GJ groups were decreased by >50% compared with the control check (CK) and SA groups. Meanwhile, surimi gels added with PJ and GJ presented lower lipid and protein oxidation degrees. The verification test indicated that PJ and GJ\'s aroma had a masking effect on the WOF. In conclusion, PJ and GJ reduced the WOF in surimi gels by preventing WOF compounds\' production and masking the WOF with their distinct aroma.

The quality of the Dahongpao mother tree (Camellia sinensis) remains a mystery to this day. In this study, for the first time, the differences between the Dahongpao mother tree (MD) and Dahongpao cuttings (PD), in terms of odor characteristics and taste characteristics were analyzed by metabomics. The results showed that MD had stronger floral, fruity, green, and woody odor characteristics than PD, and that the contributions were mainly from dihydromyrcenol, methyl salicylate, 2-isobutylpyrazine, 1,6-dihydrocarveol, gamma-terpineol, and linalyl acetate. Further, fresh and brisk taste and mellowness taste characteristics of MD were significantly higher than PD, with contributions mainly from amino acids and derivatives and organic acids. Secondly, bitterness taste characteristics of PD were significantly higher than MD, with contributions from phenolic acids, flavones, and flavonols. This study preliminarily unraveled the legend of the superior quality of the Dahongpao mother tree, and also provided an important reference for the breeding of tea-tree cuttings.

Aviation mutagenesis is a fast and efficient breeding method. In this study, we analyzed the effect of aviation mutagenesis on volatile compounds and odor characteristics in Dahongpao fresh leaves and gross tea for the first time. The results showed that aviation mutagenesis significantly increased the total volatile compounds of Dahongpao fresh leaves and gross tea. Aviation mutagenesis most critically significantly increased the content of beta-myrcene in Dahongpao fresh leaves, prompting its conversion to beta-pinene, cubebol, beta-phellandrene, zingiberene, (Z,Z)-3,6-nonadienal, and 6-pentyloxan-2-one after processing, which in turn enhanced the fruity, green, spicy, and woody odor characteristics of the gross tea. This study provided a reference for further exploration of aviation mutagenic breeding of Camellia sinensis.

The present study has successfully established a scientific and precise approach for distinguishing the geographical origins of young citrus fruits (Qingpi) from four primary production regions in China, using gas chromatography-mass spectrometry (GC-MS) and flash gas chromatography electronic nose (flash GC e-nose) to analyze the volatile composition and odor characteristics. Through the application of chemometric analysis, a clear differentiation among Qingpi samples was established using GC-MS. Additionally, the application of flash GC e-nose facilitated the extraction of flavor information, which enabled the discrimination of geographical origins. Several flavor components were identified as significant factors for origin certification. Furthermore, two pattern recognition algorithms were employed to achieve high accuracy in regional identification. The results of this investigation demonstrate that the amalgamation of multivariate chemometrics and algorithms can proficiently discern the sources of those young citrus fruits. The findings of this research can provide a reference for the assessment of quality control in food and other agricultural commodities in the times ahead.

Internal mildewed nutmeg is difficult to perceive without cutting the nutmeg open and examining it carefully, which poses a significant risk to public health. At present, macroscopic identification and chromatographic analysis are applied to determine whether nutmeg is moldy or not. However, the former relies on a human panel, with the disadvantages of subjectivity and empirical dependence, whilst the latter is generally time-consuming and requires organic solvents. Therefore, it is urgent to develop a rapid and feasible approach for evaluating the quality and predicting mildew in nutmeg. In this study, the quality and odor characteristics of five groups of nutmeg samples with different degrees of mildew were analyzed by using the responses of an electronic nose combined with chemical profiling. The main physicochemical indicators, such as the levels of α-pinene, β-pinene, elemicin, and dehydro-di-isoeugenol, were determined. The results revealed that the contents of α-pinene, β-pinene, and elemicin changed significantly with the extension of storage time. Through the use of an electronic nose and HS-GC-MS technology to assess the overall odor characteristics of nutmeg samples, it was found that the production of volatile organic compounds (VOCs) such as ammonia/organic amines, carbon monoxide, ethanol, and hydrogen sulfide, as well as changes in the terpene and phenylpropene components of the nutmeg itself, may be the material basis for the changes in odor. The accuracy of the qualitative classification model for the degree of mildew in nutmeg was higher than 90% according to the electronic nose data combined with different machine learning algorithms. Quantitative models were established for predicting the contents of the chemical components, and models based on a BP neural network (BPNN), the support vector machine (SVM), and the random forest algorithm (RF) all showed good performance in predicting the concentrations of these chemical components, except for dehydro-di-isoeugenol. The BPNN performed effectively in predicting the storage time of nutmeg on the basis of the E-nose\'s responses, with an RMSE and R2 of 0.268 and 0.996 for the training set, and 0.317 and 0.993 for the testing set, respectively. The results demonstrated that the responses of the electronic nose (E-nose) had a high correlation with the internal quality of nutmeg. This work proposes a quick and non-destructive evaluation method for the quality of nutmeg, which has high accuracy in discriminating between different degrees of mold in nutmeg and is conducive to early detection and warning of moldy phenomena.

Odor annoyance was a kind of environmental air pollution. Compared to other indoor environments, vehicle interior materials were not well studied. Especially, there had been little research on odor character of the railway vehicles. This study applied the OAV method to identify the key odorants of railway vehicle materials and discussed the characteristics of these odorants through Weber Fechner law and a dual variable method. The result showed that for single odorant, Weber Fechner law can be used to estimate the perceived intensity of an odor gas sample at different concentration levels. The odorant with smaller slope had significant tolerance to human. For the mixtures of odorants, the overall intensity of the mixture is generally dominated by the strongest odor intensity of the individual substance in the mixture, and positive interaction effect can be observed in mixtures whose intensities had little difference. But there was a kind of odorants, such as methacrylate, in which a very small variation in the concentration of mixtures can affect its odor intensity largely. Meanwhile, the odor intensity modification coefficient was an effective way to identify and evaluate odor interaction effect. The interaction potential of the studied odorants from strong to weak was methacrylate, dibutyl-amine, nonanal, 2-ethyl hexanol. The odor interaction potential and odor nature should be paying much attention in the improvement of odor in railway vehicle product.

Fermentation is extremely important for the formation of the special flavor of Wuyi rock tea. This study determined volatile metabolite contents using GC-MS technique and futher analyzed their odor characteristics during the traditional deep fermentation technology of Wuyi rock tea. The results showed that 17 characteristic compounds significantly changed during the first stage of the preliminary processing, namely fresh leaves, withering and fermentation. The key to the formation of floral aroma lied in dihydromyrcenol, and the woody aroma derived from six terpenoids, and their synthesis depended on dihydromyrcenol content. The fruity aroma was dominated by six esters, and the fruity aroma mainly came from (Z) -3-hexen-1-yl butyrate, (E) -3-hexen-1-yl butyrate and 5-Hexenyl butyrate. This study provided an important theoretical and practical basis for improving the preliminary processing of Wuyi rock tea.

Bis (2-chloro-1-methylethyl) ether (DCIP), one U.S. Environmental Protection Agency priority pollutant, could pose health and/or odor risk in water environment. In this study, odor characteristics, occurrence and source of DCIP in drinking waters of China were investigated based on sensory analysis and a nation-wide investigation covering 140 drinking water treatment plants. Then multi-risk integrated health and aesthetic aspects through oral and inhalation (showering) exposure by drinking water were first estimated. Sensory evaluation showed DCIP exhibited \"solvent-like\" odor with thresholds of 34.8 ng/L in air and 142.0 ng/L in water. DCIP was detected at comparable concentrations in raw and finished waters (<1280 ng/L) and was by-product from industrial production of epichlorohydrin/propylene oxide. Lifetime Average Daily Dose through oral exposure was 0-36.65 ng/day/kg, corresponding to odor activity values of 0-8.4 and hazard quotients of far < 1, indicating drinking tap water might cause odor issues rather than significant health hazard. The proportion of sensitive population to DCIP\'s odor was 6.1%. In contrast, residents rarely detect DCIP\'s odor by inhalation. The presence in drinking water as industrial by-product, poor removal using conventional water treatment and potential to be T&O issues, indicates urgent demand for pollutant source control to protect DCIP from entering source waters.

Benshan tea is a kind of oolong tea, and Benshan (Camellia sinensis) tea tree originates from Anxi County of Fujian Province in China, which is a national tea tree breed. Tea processing is the key to the formation of its odor characteristics. It is extremely important to step by step analyze effects of tea processing on aroma intensity and the formation of odor characteristics for optimizing tea processing process and improving tea quality. The results of this study showed that processing resulted in a significant increase in the content of volatile compounds in tea leaves, i.e., from 25.213 μg/kg to 111.223 μg/kg, in which the volatile compounds were mainly terpenoids. Secondly, the analysis found that 20 kinds of key compounds constituted to odor characteristics of Benshan tea leaves, among which geraniol, trans-β-ionone, gerol, citronellol, benzeneacetaldehyde, and trans-nerolidol were the most key six. Floral and fruity aromas, especially floral aroma, mainly formed odor characteristics of Benshan tea after processing, while floral aroma mainly came from the contribution of geraniol, which was the foremost compound in the formation of floral aroma of Benshan tea.

Processing is extremely important for the formation of aroma characteristic of tea leaves. In this study, the effects of processing on the content of volatile compounds, aroma intensity and odor characteristic of Shuixian tea were analyzed. The results showed that the content of volatile compounds in Shuixian tea increased significantly after processing, among which terpenoids and esters were the highest. There were 18 key compounds constituting the aroma characteristics of Shuixian tea, among which geraniol and nerol were the most important compounds, which contributed 96.28% to the aroma of Shuixian tea. The odor characteristics of Shuixian tea were mainly floral and fruity and the contribution of floral mainly came from geraniol, while fruity mainly came from nerol. Geraniol and nerol compounds increased rapidly after the withering process of tea leaves. This study provided an important reference for the improvement of processing technology and quality enhancement of Shuixian tea.