Comparison of Volatile Compounds in Jingshan Green Tea Scented with Different Flowers Using GC-IMS and GC-MS Analyses.

Scented green tea (Camellia sinensis) is a type of reprocessed green tea produced by scenting with flowers. To investigate the differences in the volatiles of scented green tea processed with four different flowers (Jasminum sambac, Osmanthus fragrans, Michelia alba, and Rosa rugosa), gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS) were employed to detect and identify the volatile compounds in the four types of scented teas. GC-IMS and GC-MS identified 108 and 101 volatile compounds, respectively. The key characteristic volatile compounds, namely indole, linalool, ß-myrcene, benzyl acetate, and ethyl benzoate (jasmine tea); cedrol, (E)-ß-ionone, γ-decalactone, and dihydro-ß-ionol (osmanthus tea); geraniol, phenylethyl alcohol, jasmone, methyl jasmonate, hexadecanoic acid, 4-ethyl-benzaldehyde, 2-methylbutyl hexanoate, and indole (michelia tea); and 3,5-dimethoxytoluene, (E)-ß-ionone, and 2-methylbutyl hexanoate (rose tea), were identified through chemometric analysis combined with relative odor activity values (ROAVs) and sensory evaluation. This study provides new insights into the formation of aroma molecular fingerprints during green tea scenting with flowers, providing theoretical guidance for infusing distinct aroma characteristics into green tea during scented tea processing.

1H NMR Spectroscopy Combined with Machine-Learning Algorithm for Origin Recognition of Chinese Famous Green Tea Longjing Tea.

Premium green tea is a high-value agricultural product significantly influenced by its geographical origin, making it susceptible to food fraud. This study utilized nuclear magnetic resonance (NMR) spectroscopy to perform chemical fingerprint analysis on 78 Longjing tea (LJT) samples from both protected designation of origin (PDO) regions (Zhejiang) and non-PDO regions (Sichuan, Guangxi, and Guizhou) in China. Unsupervised algorithms and heatmaps were employed for the visual analysis of the data from PDO and non-PDO teas while exploring the feasibility of linear and nonlinear machine-learning algorithms in discriminating the origin of LJT. The findings revealed that the nonlinear model random forest (92.2%), exhibited superior performance compared to the linear model linear discriminant analysis (85.6%). The random forest model identified 15 key marker metabolites for the geographical origin of LJT, such as kaempferol glycoside, glutamine, and ECG. The results support the conclusion that the integration of NMR with machine-learning classification serves as an effective tool for the quality assessment and origin identification of LJT.

Kappa-carrageenan and xylooligosaccharide effect on water mobility and structural changes in silver carp proteins during frozen storage.

BACKGROUND: The cryoprotective effect of xylooligosaccharide (XO) and kappa-carrageenan (KC) mixture on silver carp proteins in fluctuated frozen storage from 4 to -18 °C was analyzed. Positive control as a conventional cryoprotectant mixture of sucrose (4%) and sorbitol (4%), KC (3%) and XO/KC (3%) treatments were incorporated in silver carp surimi and myofibrillar proteins to analyze the water mobility and its influence on structural attributes. RESULTS: The temperature fluctuation significantly increased the structural alteration in samples with no treatments due to oxidative changes, protein denaturation and recrystallization. Meanwhile, the mixture of XO and KC (XO/KC 3%) significantly reduced the tertiary and secondary structural alterations by preventing the oxidative changes in α-helix and tryptophan (Trp) residues. Moreover, XO/KC (3%) inhibited water mobility, hindering the T22 relaxation time, as compared to the samples added with KC (3%) and the positive control. Interestingly, the XO/KC (3%) mixture significantly reduced the formation of extracellular spaces and recrystallization by restricting the partial dehydration of muscles and extracellular solution concentration. CONCLUSION: From the current results, it can be concluded that the XO/KC mixture could be efficient in protecting aquatic food proteins during fluctuating frozen storage by preventing the exposure of Trp residues and α-helix contents. Moreover, XO/KC restricted the water mobility by establishing a bond and making water unavailable for crystallization and recrystallization. Therefore, XO/KC could be used as an effective mixture to prevent fluctuated and frozen storage changes in aquatic foods. © 2024 Society of Chemical Industry.

Cake of Japonica, Indica and glutinous rice: Effect of matcha powder on the volatile profiles, nutritional properties and optimal production parameters.

Matcha addition decreased the relative crystallinity and provided with a refreshing flavor for all types of rice cakes. Matcha also significantly enhanced the phenolic content and the oxidant defense of cakes. Compared with the other two types of rice cakes, the one made of glutinous rice are with the lowest starch digestibility. Adding matcha to rice cakes inhibited the in vitro starch digestion, and a significant decrease in the expected glycemic index (eGI) and an increase in resistant starch (RS) were observed. Besides, according to the results of sensory evaluation, an optimized formulation of matcha rice cake was expected to contain 1.6% matcha, 82% water and steamed for 39 min. These findings suggest that matcha could be a favorable food additive to improve both the flavour and nutritional value of steamed rice cake.

Bufalin induces apoptosis and autophagy via the Ca2+/CaMKKß/AMPK/Beclin1 signaling pathway in osteosarcoma cells.

Bufalin, a major cardiotonic compound of the traditional Chinese medicine Chanshu has been used for cancer treatment for several years. However, the molecular mechanisms of Bufalin-induced autophagy in osteosarcoma (OS) is not fully understood. In the present study, it was shown that Bufalin induced crosstalk between apoptosis and autophagy, which resulted in OS cell death. Mechanistically, Bufalin induced autophagy by increased the ratio of microtubule-associated protein 1A/1B-light chain 3 (LC3)-II/LC3-I, and inducing apoptosis via the caspase-dependent pathway. Inhibition of autophagy promoted Bufalin-induced cell death. In contrast, suppression of apoptosis enhanced Bufalin-induced autophagy. In addition, it was found that Bufalin activated the Ca2+ /calmodulin-dependent protein kinase ß/AMPK/Beclin1 pathway, which resulted in induction of autophagy. These findings provide a mechanistic understanding of the means by which Bufalin mediates autophagy and apoptosis in OS cells.

Chlorogenic acid combined with epigallocatechin-3-gallate mitigates D-galactose-induced gut aging in mice.

Chlorogenic acid (CGA) and epigallocatechin-3-gallate (EGCG) are major polyphenolic constituents of coffee and green tea with beneficial health properties. In this study, we evaluated the gut protecting effect of CGA and EGCG, alone or in combination, on D-galactose-induced aging mice. CGA plus EGCG more effectively improved the cognition deficits and protected the gut barrier function, compared with the agents alone. Specifically, CGA plus EGCG prevented the D-galactose mediated reactive oxygen species accumulation by increasing the total antioxidant capacity, reducing the levels of malondialdehyde, and suppressing the activity of the antioxidant enzymes superoxide dismutase and catalase. In addition, supplementation of CGA and EGCG suppressed gut inflammation by reducing the levels of the proinflammatory cytokines TNFα, IFNγ, IL-1ß and IL-6. Moreover, CGA and EGCG modulated the gut microbiome altered by D-galactose. For instance, CGA plus EGCG restored the Firmicutes/Bacteroidetes ratio of the aging mice to control levels. Furthermore, CGA plus EGCG decreased the abundance of Lactobacillaceae, Erysipelotrichaceae, and Deferribacteraceae, while increased the abundance of Lachnospiraceae, Muribaculaceae, and Rikenellaceae, at the family level. In conclusion, CGA in combination with EGCG ameliorated the gut alterations induced by aging, in part, through antioxidant and anti-inflammatory effects, along with its gut microbiota modulatory capacity.

Effects of Tea Powder on the Cooking Properties, Antioxidative Potential and Volatile Profiles of Dried Noodles.

Numerous studies indicate that tea has versatile health benefits, and attempts are being made to use it as a food additive. In this study, three types of tea powder (TP) [matcha tea powder (MTP), green tea powder (GTP), and black tea powder (BTP)] were used in noodle processing, and the cooking properties, antioxidant potential, and volatile profiles of dried tea noodles (DTN) were investigated. Between 0.5% and 2% TP addition decreased the cooking time, cooking loss, and water absorption of DTN, regardless of concentrations. TP decreased the brightness (L*) of the DTN while increasing the greenness (|-a*|) and yellowness (b*) values of matcha tea noodles (MTN) and green tea noodles (GTN), as well as the redness (a*) and yellowness (b*) values of black tea noodles (BTN). The results of the 1,1-Diphenyl-2-Picrylhydrazyl (DPPH) scavenging activity (10.84-95%), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free scavenging activity (2.03-92.23%), and total phenolic content (TPC) (97.32-540.97 mg/g) of the noodles increased as the TP addition increased. Besides, TP also enriched the flavor of the DTN, with alcohol, aldehydes, and ethers being the main components. In conclusion, the addition of TP positively improved the quality of the DTN and increased its antioxidative potential.

(-)-Epigallocatechin-3-gallate mitigates cyclophosphamide-induced intestinal injury by modulating the tight junctions, inflammation and dysbiosis in mice.

Cyclophosphamide (CTX) is an antitumor drug commonly used to treat various cancer types. Unfortunately, its toxic side effects, including gastrointestinal (GI) toxicity, affect treatment compliance and patients' prognosis. Thus, there is a critical need of evaluating strategies that may improve the associated GI toxicity induced by CTX. In this work, we evaluated the capacity of epigallocatechin-3-gallate (EGCG), a major constituent of green tea, to improve the recovery of gut injury induced by CTX in mice. Treatment with CTX for 5 days severely damaged the intestinal structure, increased immune-related cytokines (TNFα, IL-10 and IL-21), reduced the expression levels of tight junction proteins (ZO-1, occludin, claudin-1), induced reactive oxygen species, altered the composition of gut microbiota, and reduced short chain fatty acid levels. EGCG treatment, starting one day after the last CTX dose, significantly improved the intestinal structure, ameliorated gut permeability, and restored ZO-1, occludin and claudin-1 levels. Moreover, EGCG reduced TNFα, IL-10 and IL-21 levels and decreased oxidative stress by regulating the activities of the antioxidant enzymes catalase, superoxide dismutase and glutathione peroxidase. Finally, EGCG treatment restored the composition of gut microbiota and the levels of the short chain fatty acids. In conclusion, these findings indicate that EGCG may function as an effective bioactive compound to minimize CTX-induced GI tract toxicity.