Effect of Fermentation Processing on the Flavor of Baijiu

Baijiu, otherwise known as the national liquor of China, is a well-known distilled spirit that has been produced for over 2000 years. Baijiu is a clear and transparent fermented alcoholic beverage containing more than 1870 volatile compounds, including esters, alcohols, aromatics, ketones, heterocycles, nitrogenous compounds, acids, aldehydes, terpenes, sulfur compounds, acetals, and lactones. This perspective describes the baijiu production process, summarizes recent progress in the development and study of baijiu flavor chemistry, discusses the effect of fermentation processing on baijiu flavor, and presents novel development trends in the baijiu industry in the dual directions of flavor and health. Furthermore, the direction of research and development for modernization in the baijiu industry is discussed and proposed

Detection of clothianidin residues in cucumber and apple juice using lateral-flow immunochromatographic assay

Clothianidin (CTA), third generation neonicotinoid insecticide that has been widely used for the long-term control of a wide variety of pests. Therefore, we developed immunochromatographic assay for the detection of CTA residues in cucumber and apple juice. The antigen HCTA-EDC-OVA and the goat anti-mouse IgG antibody were added to a nitrocellulose membrane as the test and control lines, respectively. Under optimal conditions, the cut-off limits of the semi-quantitative strip test for CTA were 1 ng/mL in 0.01 M PBS (pH 7.4), 4 ng/mL in cucumber juice, and 5 ng/mL in apple juice, and the results were obtained within 5 min. The immunochromatographic assay can be used for the sensitive, rapid, and specific on-site screening of CTA residues in cucumber and apple juice.</p

Characterization and Comparison of Aroma Profiles and Aroma-Active Compounds between Traditional and Modern Sichuan Vinegars by Molecular Sensory Science

Aroma profiles and aroma-active compounds of Sichuan vinegar, which is one of the four famous vinegars in China, were systemically analyzed by solvent-assisted flavor evaporation-gas chromatography-mass spectrometry (SAFE-GC-MS) and gas chromatography-olfactometry (GC-O). In addition, descriptive profile analysis, aroma reconstitution, and omission test were used to evaluate and compare the Sichuan modern vinegar (SMV) and Sichuan traditional vinegar (STV). A total of 99 volatile compounds were tentatively identified from the neutral and acidic fractions of both samples. Among them, 77 compounds were positively identified after comparison with their corresponding standards. Forty-two aroma-active compounds were characterized with flavor dilution (FD) factors from 1 to 6561 by aroma extract dilution assay (AEDA)-GC-O, with the highest for 2-hydroxy-3-butanone, butyrolactone, furan-2-carbaldehyde, acetic acid, and 3-oxobutan-2-yl acetate in both STV and SMV samples. Among them, 10 were identified for the first time in vinegar. Moreover, 40 aroma-active compounds were quantitatively determined, and 26 compounds exhibited their odor activity values (OAVs) larger than 1. The reconstituted solutions showed similar aroma profiles to the original samples in their characteristic aromas in terms of fruity, sweet, roasty, spicy, and woody notes but had slight differences in nutty and herbal notes

Amino-Acid-Encoded Supramolecular Self-Assembly Architectures: Near-Infrared Fluorescence–Photothermal Temperature Dual-Signal Sensing of Hydrogen Peroxide

Detection of hydrogen peroxide (H2O2) is important for maintaining human health and environmental safety because an abnormal intake of H2O2 can lead to serious pathological conditions. However, reported fluorescent probes are still limited to the visible region, and complementarity with other detection modes to further ensure reliable detection results and readable signal output has not been attempted. Herein, we modulated the self-assembly process of linear tripeptides and nonpeptide biomolecules by means of amino acid encoding, including supramolecular morphology and energy conversion pathways, to obtain self-assembled peptide architectures that combine high fluorescence brightness and comparable photothermal properties. Using this peptide self-assembler as a signal carrier, near-infrared fluorescence–photothermal temperature dual-signal detection of H2O2 was achieved for the first time with the assistance of gold nanoparticles, with limits of 0.16 μM for near-infrared (NIR) fluorescence detection and 12.0 μM for photothermal detection. Furthermore, the electrostatic spinning technique was used to deposit the conjugate onto cellulose acetate membranes, which facilitated portable fluorescence imaging sensing of H2O2 in real samples. This work not only develops the first NIR fluorescent–photothermal temperature sensor targeting H2O2 but also demonstrates an organizational approach using biocompatible peptides as building blocks, pushing nanotechnologies toward a greener and sustainable development path

Photostimulus-Responsive Peptide Dot-Centered Covalent Organic Polymers: Effective Pesticide Sensing via Enhancing Accessibility

Pesticide detection and monitoring are necessary for human health as the overapplication has serious consequences for environmental pollution. Herein, a proper modulation strategy was implemented to construct the photostimulus-responsive peptide-dot-centered covalent organic polymer (P-PCOP) nanoarchitecture for selective sensing of pesticides. The as-constructed P-PCOP was prepared at room temperature by using amino-containing peptide dots as a building block instead of common organic molecules, and the merits of P-PCOP enable it to reduce the steric hindrance of recognition, enhance the interfacial contact of the target, and facilitate the accessibility of sites, which promises to improve the sensitivity. The P-PCOF exhibited a low detection limit of 0.38 μg L–1 to cartap over the range of 1–80 μg L–1 (R2 = 0.9845), and the recoveries percentage in real samples was estimated to be 93.39–105.82%. More importantly, the DFT calculation confirmed the selective recognition ability of P-PCOP on chemical pesticides. In conjunction with a smartphone-integrated portable reading device, on-site chemical sensing is achieved. The proper modulation strategy of fixing a functional guest on the COP system contributes to the advanced structure-chemical properties that are conducive to their applications in chemical sensing

A Robust Ratiometric Fluorescent Sensor Based on Covalent Assembly of Dipeptides and Biomolecules for the High-Sensitive and Optosmart Detection of Pyrethroids

In this study, two ultrashort dipeptides, diphenylalanine (FF) or C-terminal amidated diphenylalanine (DPA), were covalently self-assembled with genipin to obtain two well-defined supramolecular peptide nanoparticles for the detection of pyrethroids. DPA-genipin nanoparticles (PNPs) demonstrated excellent dual-emission fluorescence characteristics, tunable particle size, and robust photostability. Parallel to this, PNPs showed a ratiometric fluorescence response to λ-cyhalothrin (LC) with a distinct green-to-red color transition. The satisfactory self-calibration capability of the ratiometric system enabled PNPs to respond sensitively to LC in a wide range (5–800 μg/L) with a lower limit of detection of 0.034 μg/L. The introduction of a smartphone application made it easy to develop an intelligent evaluation platform based on PNPs, which had been proven to be applicable for on-site visualization of LC in agricultural products. The platform proposed here may be a new application of peptide self-assembly in sensing, with both important food safety implications and great economic value

Identification and Inhibition of the Key Off-Odorants in Duck Broth by Means of the Sensomics Approach and Binary Odor Mixture

To improve the sensory quality and promote the diversified development of duck meat, the identification and inhibition of key off-odorants in duck broth were comparatively characterized by using the sensomics approach and binary odor mixture analysis. Sensory evaluation results showed that Litsea pungens Hemsl (LPH) could strongly inhibit the duck broth off-odorants. Fifty-four aroma-active compounds with flavor dilution factors ranging from 1 to 2048 were identified in duck broth and duck broth stewed by LPH. Recombination and omission tests confirmed that trans-4,5-epoxy-(E)-2-decenal, (E)-2-octenal, p-cresol, 1-octen-3-ol, and 4-methyloctanoic acid were the key off-odorants in duck broth. Additionally, trans-4,5-epoxy-(E)-2-decenal (9.26 μg/L) and p-cresol (718.91 μg/L) were identified as the key off-odorants in duck meat for the first time. The results of binary odor mixture and off-odorants inhibition curves demonstrated that linalool with the lowest theoretical inhibitory concentration (109.65 μg/L) had the best aroma masking ability among the five off-odorants, followed by geraniol (123.03 μg/L), (Z)-3,7-dimethyl-2,6-octadien-1-ol (301.99 μg/L), (E)-3,7-dimethyl-2,6-octadienal (2187.76 μg/L), and (Z)-3,7-dimethyl-2,6-octadienal (2691.53 μg/L). The spiking test verified that these compounds with the lowest theoretical inhibitory concentrations effectively inhibited the off-odorants of duck broth

Expression of genes related to monacolin K (<i>mokA-mokI</i>) at different phases (2, 5, 8, and 12 days) of <i>M</i>. <i>purpureus</i> M1 and M1-36.

Bar graphs illustrate gene expression levels at different times and in different strains. (A) mokA; (B) mokB; (C) mokC; (D) mokD; (E) mokE; (F) mokF; (G) mokG; (H) mokH; and (I) mokI. Data represent the mean ± SD of three independent biological replicates.</p

Transcript homology of five <i>M</i>. <i>purpureus</i> cultivars and Venn diagram of the number of orthologous transcripts (E-value = 1e^-5).

<p>Venn diagram includes 31 possible intersections between five libraries, and the number of genes shows in each of these overlapping categories. Transcriptome data sets are as follows: COG (light-green color), pfam (light-yellow color), Nr (light-purple color), Uniprot (light-pink color), and Est (light-blue color), the immature embryos.</p

The content of monacolin K were detected by HPLC in different <i>M</i>.<i>purpureus</i> cultivars.

(A) M3 was from the stabilization phases of M1-36. (B) M1-2 was from the stabilization phases of M1. (C) MW was the maximum monacolin K biosynthesis quality phase of M1. In the HPLC detection system, monacolin K peak appears about 21.300 min in every 30 minutes.</p