Inhibitory effects of apple polyphenol extract (AP) and procyanidin contained in AP on in vitro pancreatic lipase activity and in vivo triglyceride absorption in mice and humans were examined. AP and procyanidin considerably inhibited in vitro pancreatic lipase activity. However, polyphenols, except for procyanidin, in AP (i.e., catechins, chalcones, and phenol carboxylic acids) showed weak inhibitory activities on pancreatic lipase. Procyanidins separated by normal-phase chromatography according to the degree of polymerization were also examined. Inhibitory effects of procyanidins increased according to the degree of polymerization from dimer to pentamer. On the other hand, pentamer or greater procyanidins showed maximal inhibitory effects on pancreatic lipase. These results suggested that with respect to in vitro pancreatic lipase inhibition, the degree of polymerization was an important factor and oligomeric procyanidin mainly contributed. Next, we performed a triglyceride tolerance test in mice and humans. Simultaneous ingestion of AP and triglyceride significantly inhibited an increase of plasma triglyceride levels in both models. These results suggested that the oligomeric procyanidins contained in AP inhibited triglyceride absorption by inhibiting pancreatic lipase activity in mice and humans.

Oligomeric Procyanidins in Apple Polyphenol Are Main Active Components for Inhibition of Pancreatic Lipase and Triglyceride Absorption [Erratum: 2007 July 11, v. 55, no. 14, p. 5906.]

Molecular mechanisms underlying health benefits of tea compounds

The bitter and astringent taste of tea and tea extract is still not favored by many consumers, which limits its applications to bakery foods and functional foods. Many bitter and astringent compounds in tea leaves are susceptible, which transform during tea processing or can be modified by food production technologies. Besides, the accumulations of the major bitter and astringent compounds in fresh tea leaves, such as alkaloids and flavonoids, can be regulated by agronomic practices. Many attempts have been made to reduce the bitter and astringent compounds, in order to improve the sensory quality of tea and tea products. The aim of this review is to describe the characteristics of major bitter and astringent compounds in different types of teas as well as the bitterness and astringency reducing strategies from the aspects of preharvest, processing and post-processing. Alkaloids, catechins, anthocyanins, phenolic acids, flavonol glycosides, and theaflavins importantly contribute to the bitter and astringent taste of tea infusion, the contents of which can be modulated during preharvest, processing, and post-processing. Shade treatment is a conventional agronomic practice to reduce the bitterness and astringency of tea. Processing methods like oxidation, roasting/baking and microbial fermentation effectively reduce the bitter and astringent intensities of teas, but have restricted applications to special types of tea. There is a need of new compounds or strategies to decrease the bitterness and astringency of tea and tea products. Employment of these bitterness and astringency reducing strategies should consider the appearance or application requirements of final products. 

Bitterness and astringency of tea leaves and products: Formation mechanism and reducing strategies

In the present study, volatile compounds from 15 yellow tea samples were extracted and examined using stir bar sorptive extraction (SBSE) combined with gas chromatography-mass spectrometry (GC-MS), and the key odorants were identified by gas chromatography-olfactometry (GC-O) analysis. Results revealed 74 volatile compounds in these yellow teas, geraniol (3.89 μg/g) being the most abundant aroma compound. Alcohols and esters were the dominant volatiles, accounting for approximately 52.44% of the total volatiles in content. Moreover, 25 key odorants were identified by GC-O method, and were considered to be responsible for the unique aroma quality of yellow tea. Major key odorants included (E, E)-3,5-octadien-2-one, (Z)-linalool oxide (furanoid), (E)-2-heptenal, naphthalene, geraniol, (E)-linalool oxide (furanoid), styrene, linalool, α-ionone, 1-octen-3-ol, trans-β-ionone, and (E, Z)-3,5-octadien-2-one. In addition, huge differences were observed among the content levels of key odorants in three types of yellow tea samples, namely MengDingHuangYa (MDHY), WeiShanHuangCha (WSHC), and PingYangHuangTang (PYHT). This is an important study describing the characterization of aroma and key odorants in yellow tea. The results obtained from this study advance our understanding of the aroma quality of yellow tea, thereby providing a theoretical basis for the processing and quality control of yellow tea aroma quality.

Volatile components and key odorants of Chinese yellow tea (Camellia sinensis)

Yellowing is the key process used to produce the unique yellow tea, but the effect of the yellowing process on tea quality and chemical composition remains unclear. Here, electronic eye and tongue and metabolomics were applied to investigate dynamic changes in tea leaves during the yellowing process for the first time. During the first 18 h of yellowing, the colour of tea leaves was observed becoming yellowish. Compounds related to umami and sweetness (amino acids, catechins, sucrose, phenolic acids, etc.) are at high levels. However, after 24 h of yellowing, the colour of tea becomes darker, with richness of tea infusion decreasing significantly. The levels of most catechins, amino acids, phenolic acids, and glycosidically bound volatiles (GBVs) decreased significantly, whereas betaine, piperidine, theasinensin B, and lysophosphatidylcholines (LPCs) increased significantly. Meanwhile, according to partial least-squares (PLS) analysis, most amino acids and sucrose were positively correlated with umami and sweetness; most catechins and phenolic acids had positively correlated with bitterness and astringency; phaeophorbides were positively correlated with red value (+a*) of tea leaves’ colour. This work provides a comprehensive, novel knowledge on the quality and chemical changes of yellow tea during the yellowing process.

The profile of dynamic changes in yellow tea quality and chemical composition during yellowing process

The invention discloses a tea buccal tablet capable of protecting liver, and a preparation method thereof. The tea buccal tablet is prepared from, by weight, 150 to 200 parts of penthorum chinense pursh, 100 to 150 parts of fiveleaf gynostemma herb, 30 to 50 parts of fructus schisandrae chinensis, 50 to 80 parts of codonopsis pilosula, 50 to 80 parts of astragalus membranaceus, 10 to 20 parts of EGCG monomer, 150 to 200 parts of talcum powder, 15 to 20 parts of mint powder, 20 to 50 parts of sorbitol, 5 to 7 parts of magnesium stearate, and 3 to 5 parts of microcrystalline cellulose. Preparation process and technology are specifically disclosed in the preparation method. The tea buccal tablet is capable of protecting liver, improving human immunity, and satisfying living needs, and is promising in market prospect.

Tea buccal tablet capable of protecting liver, and preparation method thereof

The invention discloses a method for discriminating the origin of fresh leaves of Enshi Yulu tea by using an extreme learning machine spectral model, related to the technical field of agricultural product origin identification. The method for discriminating the origin of the fresh leaves of Enshi Yulu tea by using the extreme learning machine spectral model is characterized by comprising the following steps: scanning to obtain near-infrared spectra of fresh tea leaf samples from different origins; then pre-processing the sample spectra to eliminate noise information; then converting the samplespectra into pairs of data points, and dividing the spectral data into 20 spectral sub-intervals; using the ant colony algorithm to screen spectral information sub-interval bands reflecting the origin of the fresh leaves; and finally, inputting the optimal spectral information sub-interval information into an extreme learning machine algorithm to establish the extreme learning machine spectral model for predicting the origin of the fresh leaf samples. The method for discriminating the origin of the fresh leaves of Enshi Yulu tea by using the extreme learning machine spectral model realizes the rapid and accurate prediction of the origin of the fresh leaves of Enshi Yulu tea.

Method for discriminating origin of fresh leaves of Enshi Yulu tea by using extreme learning machine spectral model

Provided are a lemon-flavored biscuit containing dihydromyricetin and avocado and a making method thereof The biscuit is made from, by weight, 60-70 parts of butter, 40-60 parts of white powdered sugar, 10-15 parts of avocados, 90-110 parts of low-gluten flour, 15-20 parts of fresh lemon juice, 1-3 parts of edible salt and 03-05 part of dihydromyricetin The making method comprises the steps that the butter is softened, the white powdered sugar and the edible salt are added, and slight and even stirring is performed; the fresh avocado pulp is taken and stirred into paste, and then fresh squeezed lemon juice is added; the foods are mixed, the low-gluten flour and the dihydromyricetin are screened into the mixture and are stirred evenly, the made paste is put in a refrigerator and is frozen until the paste is hard; the frozen paste taken out of the refrigerator is rolled into a sheet, and the sheet is compressed into biscuit blocks; the biscuit blocks are put in a baking box, are baked at 180 DEG C for 5 minutes and then are baked at 150 DEG C for 10 minutes The nutritive values and effects of the dihydromyricetin, avocados and lemons are effectively retained, the liver can be protected, and immunity can be improved

Lemon-flavored biscuit containing dihydromyricetin and avocado and making method thereof

The invention discloses a brick tea steam generating and heating device which comprises a furnace body (2), a water storage tank (3), a water pump (5), a steam cover (22) and a control box (21), wherein a water escape valve (13) is arranged at the bottom of the furnace body (2); a liquid level sensor (7), a safety valve (8) and a pressure transmitter (9) are arranged on the furnace body (2); a heating plate (12) is arranged in the furnace body (2), a water level detection switch (6) is arranged in the water storage tank (3), the water pump (5) is respectively connected with the furnace body (2) and the water storage tank (3), the steam cover (22) is connected with the furnace body (2) through a connection pipeline (23), and a second electromagnetic valve (20) is arranged on the connectionpipeline (23); the heating plate (12), the water release valve (13), the water level detection switch (6), the second electromagnetic valve (20), the liquid level sensor (7) and the pressure transmitter (9) are respectively connected with the control box (21). The brick tea steam generating and heating device has the advantages of stable steam pressure, even and identical steaming effect and ability in improving brick tea quality.

Brick tea steam generating and heating device

The invention relates to a temperature controllable brick tea mold. An upper template (25) is arranged at the bottom of an upper template frame base (17); an upper template base (18) is arranged in the upper template frame base (17) and at the bottom of an upper base plate (12); a heating plate I (36) is arranged in the upper template frame base (17) and on the upper template (25); a hold-down block (19) is arranged in the upper template base (18); a plurality of hollow cavities are formed in a mold frame plate (39); a plurality of lower template frame bases (41) are arranged on a mold frame movable plate (31) and corresponding to the upper template frame base (17); a lower template base (42) is arranged in the lower template frame bases (41) and on the upper part of the mold frame movableplate (31); the heating plate I (36) is arranged in the lower template frame base (41) and at the bottom of a lower template (20); and a hold-down block II (43) is arranged in a lower template base (42). The temperature controllable brick tea mold realizes temperature controllability, has high efficiency and completely realizes automation.

Zheng Lin

Papers

Tea buccal tablet capable of protecting liver, and preparation method thereof

Method for discriminating origin of fresh leaves of Enshi Yulu tea by using extreme learning machine spectral model

Lemon-flavored biscuit containing dihydromyricetin and avocado and making method thereof

Brick tea steam generating and heating device

Temperature controllable brick tea mold