Laoshan green teas plucked in summer and autumn were measured by high performance liquid chromatography-diode array detector (HPLC-DAD). After baseline correction, the fingerprints data were resolved by multivariate curve resolution-alternating least squares (MCR-ALS) and a total of 57 components were acquired. Relative concentrations of these components were afterwards applied to distinguish plucking seasons using principal component analysis (PCA), support vector machines (SVM) and partial least squares-discriminant analysis (PLS-DA). For both SVM and PLS-DA models, the total recognition rates of training set, cross-validation and testing set were 100%, 91.3% and 100%, respectively. Besides, three variable selection methods were employed to determine characteristic components for the authentication of summer and autumn teas. Results showed that PLS-DA model based on three characteristic components selected by VIP possesses identical predictive ability as the original model. This study demonstrated that our proposed strategy is competent for the authentication of plucking seasons of Laoshan green tea.
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http://dx.doi.org/10.1016/j.foodchem.2020.128959 | DOI Listing |
Compr Rev Food Sci Food Saf
July 2024
Tea Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs, Hangzhou, China.
Foods
December 2023
College of Food Science and Technology, Yunnan Agricultural University, Kunming 650201, China.
Tea () has grown for over 300 years and is recognized worldwide as among other well-renowned crops. The quality of black tea depends on plucking (method, standard, season, and intervals), withering and rolling (time and temperature), fermentation (time, temperature, and RH), drying (temperature and method), and storage conditions, which have a high influence on the final quality of black tea. At the rolling stage, the oxidation process is initiated and ends at the early drying stage until the enzymes that transform tea polyphenols into thearubigins (TRs) and theaflavins (TFs) are denatured by heat.
View Article and Find Full Text PDFAnimals (Basel)
April 2023
Faculty of Veterinary Medicine and Animal Science, University of São Paulo, 225 Duque de Caxias North Ave., Pirassununga 13635-900, SP, Brazil.
In this study, we evaluate the effects of intercropping pigeon pea ( (L.) Millsp.) with tropical pastures for feeding Nellore cattle and compared animal performance and enteric CH emissions with other pasture-based systems during the dry and rainy seasons of 2021.
View Article and Find Full Text PDFHeliyon
March 2023
Jimma University Laboratory of Drug Quality (JuLaDQ) and School of Pharmacy, Jimma University, Oromia, Ethiopia.
The tea plant is widely cultivated in southwest Ethiopia. But the impact of seasonal variation on monthly yield, leaf quality, and the long-term yield response potential of clones has not been studied. The objective of the study is to determine the impact of seasonal change and climate variables on the yield and leaf quality of tea plants in southwest Ethiopia.
View Article and Find Full Text PDFEcol Lett
May 2023
Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California, USA.
Although anthropogenic change is often gradual, the impacts on animal populations may be precipitous if physiological processes create tipping points between energy gain, reproduction or survival. We use 25 years of behavioural, diet and demographic data from elephant seals to characterise their relationships with lifetime fitness. Survival and reproduction increased with mass gain during long foraging trips preceding the pupping seasons, and there was a threshold where individuals that gained an additional 4.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!