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Taking the Mengku-dayecha protein extracted by alkaline extraction and acid precipitation method as the research object, taking the binding capacity of sodium taurocholate as the inspection index, the preparation process of Mengku-dayecha protein hypolipidemic peptides was optimized through single factor experiment and response surface analysis, and the optimal technology was determined. Under the conditions, the enzymatic hydrolysate was evaluated for lipid-lowering activity and amino acid composition analysis. The results showed that the best preparation conditions for Mengku-dayecha protein hypolipidemic peptides were pepsin hydrolysis for 3 h, pH2.1, substrate concentration 2.7%, enzyme substrate ratio 0.3%, and temperature 37 ℃. Under these conditions, the binding capacity of sodium taurocholate was (70.92%±0.12%). The activity evaluation results showed that the tea protein hydrolysate showed good activity in three in vitro evaluation indicators of lipid-lowering activity: The binding capacity of sodium taurocholate (EC50=6.466 mg/mL), the inhibition of pancreatic lipase (IC50=0.310 mg/mL) and the inhibition of cholesterol esterase (IC50=1.557 mg/mL). Amino acid analysis showed that the obtained Mengku-dayecha protein hypolipidemic peptides was rich in essential amino acids (34.35%), hydrophobic amino acids (31.94%) and acidic amino acids (41.06%).

Tea is an important beverage crop with a large and heterozygous genome. Here, the authors assemble the genome of the cultivar Longjing 43 and conduct a population genetics study to reveal divergent selection for disease resistance and flavor between the two variety groups.

Abstract Background Camellia sinensis ‘Huangjinju’ is an albino tea variety developed recently in China. Young leaves of ‘Huangjinju’ demonstrate bright yellow when cultivated under natural sunlight, but regreens under reduced light intensity. To elucidate the physiological and molecular mechanisms of this light-sensitive albinism, we compared leaf pigmentation, metabolites, cellular ultrastructure and transcriptome between plants cultured under natural sunlight and shade. Results Shading treatment doubled the chlorophyll concentration and regreened albino leaves; carotenoid also increased by 30%. Electron microscopy analyses showed that chloroplast not only increased in number but also in size with a complete set of components. In addition, regreened leaves also had a significantly higher concentration of polyphenols and catechins than albino leaves. At transcriptomic level, a total of 507 genes were differentially expressed in response to light condition changes. The most enriched pathways include light harvest protein complex, response to stimuli, oxidation-reduction process, generation of precursor metabolites and energy response. Conclusion The integrated strategy in this study allows a mechanistic understanding of leaf albinism in light-sensitive tea plants and suggested the regulation of gene networks involved in pigmentation and protein processing. Results from this study provide valuable information to this area and can benefit the domestication and artificial breeding to develop new albino tea varieties.