Frankincense is an important seasoning and spice known for its distinctive and intricate flavor profile. Considering the considerable variation in the aromatic quality of frankincense due to geographical origin, species diversity and cultivation conditions, frankincense from major global origins was characterized holistically for the first time. The electronic nose (E-nose) with headspace solid-phase microextraction gas chromatography–mass spectrometry (HS–SPME–GC–MS) and sensory evaluation were implemented to characterize the aroma components of 21 commercial varieties of frankincense from around the world. The results showed that a total of 149 volatile organic compounds (VOCs) of 10 categories were identified in frankincense, among which the numbers of alcohols, terpenes and esters compounds accounted for 22.15 %, 18.79 % and 15.44 % of the total VOCs of frankincense, respectively. The PLS-DA model effectively distinguished frankincense from Oman/Somalia and other origins. Furthermore, the study identified two differential VOCs with VIP > 1 in three Asian countries and five in six African countries. The total VOCs content and sensory characteristic score of “Lemon/Citrus” in Oman frankincense is significantly higher than other regions. The OAV results showed that 61 substances (e.g., Diacety, alpha-Pinene, Camphene, Myrcene) as key aroma compounds and OICS model indicated that p-Cymenol was found to contribute significantly to the citrus aroma in frankincense. This study identified the fundamental components of frankincense flavor and revealed different flavor descriptors of frankincense, which are crucial for reconstructing frankincense flavor and improving flavor quality.
As few odorous molecules in a gas mixture make a great contribution to its odor intensity, autograding in odor intensity is the key process and of great challenge in the prevention of odor pollution. In this work, the surface-enhanced Raman spectroscopy (SERS) spectra of a gas mixture from kitchen waste are detected on plasmonic MOF nanoparticle (NP) films for autograding in odor intensity. To obtain plasmonic MOF NP films with high SERS sensitivity, AgNP@ZIF-8 NPs with different shell thicknesses and adsorbing times are investigated, which is further confirmed by the simulation of electric field distribution and airflow distribution. Then, a 45 nm shell thickness and 3H adsorbing time are selected to collect the SERS spectra of the gas mixture from kitchen waste with different odor intensities. These SERS spectra point out that the odorous molecules generated from the different statuses of kitchen waste dominate the odor intensity of the gas mixture. Furthermore, autograding in odor intensities with four levels based on deep learning (DL) is achieved here. The results exhibit excellent diagnostic accuracy (93.3%) for the external held-out overall dataset, which indicates that a high-throughput, rapid, and label-free tool for screening odor intensities could be developed. Our work not only enriches the research of gas detection by SERS spectra but also improves the prevention technique of odor pollution.
Chao Wang,Wazhen Xu,Yuqi Yuan,Yuke Zhai,Tengfei Hu,Jianan Huang,Zhonghua Liu,Qin Li
The odor-active compounds in Fu-brick tea and their release behaviors during boiling-water were studied. Fifty-one odor-active compounds were identified, and their release behaviors were identified by continuously recovering 16 sections of condensed water combined with sensory, instrumental, and nonlinear curve fitting analysis. The odor intensities of condensed water and the concentrations of odor-active compounds could be significantly fitted ( p < 0.01) to power-function type curves. Hydrocarbons showed the fastest release rate, while organic acids showed the slowest. The release rates had very little correlation with their concentrations, molecular weights, and boiling points. Most odor-active compounds (≥70 %) released need to evaporate more than 24 % of the added water during boiling-water extraction. Meanwhile, on the basis of odor activity value (OAV) calculation, the aroma recombination experiments were performed to explore the odor-active compounds that made major contributions to the formation of the aroma profile of each condensed water.
危险品化学品经营许可证（带存储）