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

A tea fermentation device and a tea fermentation method using the tea fermentation device are disclosed, a ventilation pipe (10) is arranged in an inner barrel (1) of the tea fermentation device, one end of a fan (6) is connected with the ventilation pipe (10) by a pipeline (11), the other end of the fan (6) is connected with a heating and humidifying unit (2) by the pipeline (11), a temperature and humidity sensor (5) is arranged in the inner barrel (1), and the heating and humidifying unit (2), the fan (6) and the temperature and humidity sensor (5) are respectively connected with a control box (3); the fermentation method includes primarily processing a tea green body raw material, putting the tea green body raw material in the inner barrel (1), staring the fan (6), staring the heating and humidifying unit (2), and maintaining for 3-5 days. The fermentation cycle is short, the temperature and humidity control is accurate, and the quality of tea is guaranteed.

Tea fermentation device and tea fermentation method using tea fermentation device

The utility model provides a closed tealeaves evaporates pressure equipment and puts, which comprises a frame, the aspirator, movable support lives, evaporate the caddy, the header tank, the pipeline, revolving cylinder, two sets of sliders, electric cabinet and cylinder, the aspirator top at the fixed frame top of the curb plate inboard upper end of frame is provided with the switch body, the switch body is connected with revolving cylinder, movable support both sides alive are connected with two sets of sliders through the support bedplate respectively, two sets of slider sliding connection are on two inboard finding activate rails of frame curb plate, the leg joint seat is connected through the piston rod head portion of connecting block with the cylinder, movable support roof bottom alive is provided with the steam cover, evaporate the caddy setting on movable support's the roof of living, the pipeline passes header tank one end and sets up in frame curb plate outside upper end, the pipeline other end sets up in the steam cover The time of steaming can be set for, need not other timing, and it is effectual to steam even unanimity, steam is at closed operation, operation environment friendly, can apply to automation line

Closed tealeaves evaporates pressure equipment and puts

The invention provides a tea base weighing device. The tea base weighing device comprises a feed cabin (1), a secondary screw set (2), an electric control box (3) and a weighing component, the feed cabin (1) is located above an inlet of the secondary screw set (2), an outlet of the secondary screw set (2) is located above the weighing component, the front end of the secondary screw set (2) is provided with a power motor II, and the power motor II at the front end of the secondary screw set (2) and the weighing component are connected to the electric control box (3) respectively. An automation of tea base raw material weighing process is achieved, and the efficiency is high.

Tea base weighing device

The invention relates to a making method of brick tea. The making method comprises the following steps that in the step I, tea semi-finished product raw materials are put in a material bin (105), andmaterial collection is completed through material weighing barrels (121); a heating plate (49) in a furnace begins to heat, and a heating pipe (52) in a hood heats; a heating pipe (74) is started, sothat the temperature is maintained to be preset temperature; the shaping surface of a lower mold plate(81) moves upwards to stop at a position a certain distance away from the lower bottom surface ofa mold frame moving plate (92); in the step II, step III and step IV, a material dividing device (3) is driven by manipulator equipment(7) to move downwards to a preset position for collecting materials until each bin body (9) is loaded with raw materials completely; in the step V, a material distributing screw rod (11) is used for distributing materials, and material sending is completed; in thestep VI, steaming is performed to reach a set value; and in the step VII, brick pressing is completed, and when preset pressure-maintaining time is achieved, materials are taken. Automated productionis realized, the staff investment is reduced, and the production cost is reduced.

Making method of brick tea

A processing method of flower fragrance type broken green tea comprises the following steps: re-scenting of scented flowers: mixing a raw material of broken green tea, 2% of chopped fresh michelia alba flowers and 50% of jasmine flower residues with remaining fragrance after scenting, and separating tea from flowers by a screening machine when the moisture content of a tea base is 18%-22%; baking:performing drying by a chain plate type dryer until the moisture content of the tea base is 6%-7%, and then, thinly spreading the tea base to room temperature; scenting: mixing fresh jasmine flowerswith the blooming rate being 80% or above and blooming degree being 90 degrees with the tea base, and separating tea from flowers by the screening machine when the moisture content of the tea base is18%-22%; baking: performing drying by the chain plate type dryer until the moisture content of the tea base is 4.8%-5%, and then, thinly spreading the tea base to room temperature; and final scenting:selecting large white fresh jasmine flowers with the blooming degree being 95 degrees, mixing the jasmine flowers with the tea base, and separating tea from flowers when the moisture content of the tea base is 7%-8% to obtain the flower fragrance type broken green tea. The processing method effectively improves the quality of the broken green tea and the flower fragrance type broken green tea isobtained.

Zheng Lin

Papers

Tea fermentation device and tea fermentation method using tea fermentation device

Closed tealeaves evaporates pressure equipment and puts

Tea base weighing device

Making method of brick tea

Processing method of flower fragrance type broken green tea