Comprehensive untargeted lipidomic analysis of sea buckthorn using UHPLC-HR-AM/MS/MS combined with principal component analysis

Determination and comparison of lipid profiles of Chinese green tea varieties using untargeted lipidomics analysis combined with chemometrics

Tea is the most widely consumed drink in the world. Lipids as important chemical components are closely related to the flavor and quality of tea. However, the information about the lipidomic fingerprints of different Chinese green tea varieties was limited. Therefore, an untargeted lipidomics analysis combined with chemometrics was applied for discriminating Chinese green tea varieties. A total of 147 molecular species belonging to 16 lipid classes were identified. And the green tea samples exhibited high levels of phospholipids, glycolipids, linoleic acid, and linolenic acid. They play important roles in metabolic processes that could influence flavor formation. Furthermore, combined with multivariate data analysis, 8 molecular species were screened out for discriminating green tea varieties, such as PC 16:0/18:3, MGDG 18:3/18:3, PC 18:2/18:2, etc. This study offers a reference for the guarantee of quality and the prevention of fraud within the Chinese green tea market.

Addition of Lactobacillus fermentum to Fermented Sea Buckthorn (Hippophae rhamnoides L.) Fruit Vinegar Significantly Improves Its Sour Taste

Fruit vinegar is typically produced through a two-stage deep liquid fermentation involving alcohol fermentation (Saccharomyces cerevisiae) and acetic acid fermentation (Acetobacter pasteurianus). In order to enhance the flavor and texture of sea buckthorn fruit vinegar, Lactobacillus fermentum was introduced into the alcoholic fermentation stage. At the end of fermentation, the total acid and acetic acid of sea buckthorn (Hippophae rhamnoides L.) fruit vinegar were both enhanced compared with sea buckthorn vinegar brewed through the traditional liquid fermentation method, and in terms of the main active ingredients, the total flavonoid content was slightly enhanced. Non-targeted metabolomics (LC-MS) was used to characterize the characteristic metabolite profiles during the fermentation process. A total of 55 differential metabolites, including organic acids, flavonoids, and amino acids, were identified, and the contents of citric acid, malic acid, and manganic acid, which are the sources of the irritating taste of sea buckthorn berry vinegar, were significantly reduced. In addition, the co-fermentation of Lactobacillus fermentum promoted both glycolysis and the TCA cycle and also led to a significant up-regulation of aromatic metabolites, such as ethyl acetate, ethyl lactate, and ethyl caproate. These results will provide new information on the dynamics of the characterized metabolites during the fermentation of sea buckthorn fruit vinegar.

Discrimination of wild edible and poisonous fungi with similar appearance (Cantharellus albovenosus vs Omphalotus olearius) based on lipidomics using UHPLC-HR-AM/MS/MS

Mushrooms have long been appreciated as a delicacy as well as used as vital dietary supplements and food. However, poisoning from mushroom consumption remains a worldwide health problem, resulting in morbidity and mortality. In this paper, for the first time an untargeted lipidomics analysis on Omphalotus olearius (O. olearius) and Cantharellus albovenosus (C. albovenosus) was performed by ultra-high-performance liquid chromatography high-resolution accurate mass-mass spectrometry (UHPLC-HR-AM/MS/MS). A total of 350 lipid molecular species from 21 classes were detected in the two mushrooms. Based on multivariate and univariate analyses, 37 differential lipids were selected as metabolic markers for distinguishing the two mushrooms. And only 5 % (w/w) adulteration level was sufficient to identify C. albovenosus mixed with O. olearius. This study indicated that lipidomics approaches can provide high-resolution markers for food safety evaluation, which can be used as an accurate evaluation for distinguishing poisonous mushrooms from edible ones.

Visual analysis of sea buckthorn fruit moisture content based on deep image processing technology

The effect of moisture content changes during drying processing on the appearance of sea buckthorn was studied. Using computer vision methods and various image processing methods to collect and analyze images during the drying process of sea buckthorn fruit. Sea buckthorn is dried in a drying oven at a temperature of 65 °C and Level 1 wind speed conditions. The images of the entire drying process of sea buckthorn fruit were collected at 30-min intervals. Deep mining and transformation of image information through various image processing methods. By calibrating and modeling the color components, real-time online detection of the moisture content of sea buckthorn fruit can be achieved. After modeling, this article attempted to use LSTM (Long Short Term Memory) to predict the appearance of sea buckthorn fruit with supercritical moisture content. Different agricultural products adapt to different color spaces, but after standard modeling with a certain amount of data, applying color components to detect moisture content is a very good method.

Host-Guest Doping Modulated Afterglow Emission of Fluoroquinolones for Their Separation-Free Detection and Discrimination

Detection and discrimination of fluoroquinolones (FQs) are crucial for food safety but remain a formidable challenge due to their minor differences in molecular structures and the serious interferences from food matrices. Herein, we propose an afterglow assay for the detection and discrimination of FQs through modulating their room-temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) properties by a host-guest doping strategy. FQs were doped into the boric acid host, forming boronic anhydride structures and hydrogen bonds, which prompted the RTP and TADF performance of FQs by stabilizing their excited states, preventing triplet exciton quenching, and reducing the energy gap between singlet and triplet states. The FQs can be quantitatively detected through monitoring the afterglow intensity of host-guest systems, as low as 0.25 μg/mL. The differences in the afterglow intensity and emission lifetime allowed accurate discrimination of 11 types of FQs through pattern recognition methods. Aided by the delayed signal detection model of afterglow emission, the background signal and the interferences from food matrices were effectively eliminated, which endow the detection and discrimination of mixed FQs in commercial meat samples, without multiple-step separation processes.

Preparation of sea buckthorn (Hippophae rhamnoides L.) seed meal peptide by mixed fermentation and its effect on volatile compounds and hypoglycemia

This study employed mixed bacterial strains to ferment seabuckthorn seed meal into peptides, and conducted a comprehensive evaluation of the growth adaptive conditions, molecular weight distribution, volatile compounds, and in vitro hypoglycemic activity required for fermentation. Results showed that when the amount of maltose was 1.1% and MgSO4·7H2O was added at 0.15 g/L, the peptide yield reached 43.85% with a mixed fermentation of Lactobacillus fermentum, Bacillus subtilis, Lactobacillus casei, Lactobacillus rhamnosus, and Lactobacillus acidophilus. Components with a molecular weight below 1 kDa were found to be more effective in inhibiting the activity of α-amylase and α-glucosidase, with the identified sequence being FYLPKM. Finally, SPME/GC-MS results showed that 86 volatile components were detected during the fermentation of seabuckthorn seed meal, including 22 alcohols, 9 acids, 7 ketones, 14 alkanes, 20 esters, and 14 other compounds. With prolonged fermentation time, the content of acids and esters increased significantly.