scholarly journals Impact of the mosquito bug (Helopeltis theivora) infestation on the quality of tea (Camellia sinensis)

2017 ◽  
Vol 44 (2) ◽  
pp. 197-207 ◽  
Author(s):  
Razia Sultana Chowdhury ◽  
Irin Siddiqua Moly ◽  
Mainuddin Ahmed ◽  
Mohammad Shameem Al Mamun ◽  
Md Mozammel Hoque ◽  
...  
Keyword(s):  
Black Tea ◽  
Quality Parameters ◽  
Physiological Parameters ◽  
Lower Amount ◽  
Tea Leaves ◽  
Helopeltis Theivora ◽  
Tea Mosquito Bug ◽  
Chlorophyll A And B ◽  
Physiological And Biochemical

The influence of tea mosquito bug (Helopeltis theivora) infestation on the physiological and biochemical changes in tea leaves as well as quality parameters of the made tea was investigated. Results revealed that physiological parameters such as polyphenol, chlorophyll a and b, carotenoids, catechins, reducing sugar and antioxidant activity reduced when the shoots are infested by tea mosquito bug. Black tea prepared from Helopeltis infested shoots contained significantly lower amount of theaflavin and thearubigin ratio, highly polymerized substances, total liquor colour, colour index, caffeine and lipid than that of uninfested fresh tea leaves. The infestation of tea mosquito bug significantly reduced the physiological parameters of tea leaves and quality parameters of made tea that hamper the quality of drinking tea.Bangladesh J. Zool. 44(2): 197-207, 2016

Variation in Postharvest Quality Attributes of Fresh Cowpea (Vigna unguiculata L.) Beans Harvested from Different Crop Mulching Regime

2021 ◽  
Author(s):  
Pankaj Kumar Kannaujia ◽  
Sakharam Kale ◽  
Ajinath Dukare ◽  
Vijay Singh Meena ◽  
Prerna Nath ◽  
...  
Keyword(s):  
Phenolic Content ◽  
Quality Parameters ◽  
Postharvest Quality ◽  
Total Phenolic ◽  
Organic Mulch ◽  
Agronomic Practices ◽  
Total Antioxidant ◽  
Wheat Straw Mulch ◽  
Physiological And Biochemical

Background: Present study, aimed to assess effect of organic and inorganic crop mulching on physical, physiological and biochemical quality of fresh cowpea beans.Methods: Cowpea (cv. Kashi Kanchan bush-type) was grown during two consecutive seasons from April 2018 to July 2019 under four different mulching treatments. Mulching treatments included no mulch; wheat straw mulch (organic mulch); black mulch and silver mulch. Black and silver mulches were made of 25 microns LDPE sheet. Cowpea was grown as per standard agronomic practices and physical, biochemical and postharvest quality parameters of beans were evaluated.Result: Results indicated that bean length (28.7cm) was highest under silver mulch whereas bean thickness (9.10mm), width (9.29mm) and 100 bean weight (1094.5g) were highest under organic mulch. Likewise, protein content (28.63%), total phenolic content (17.0µg GAE/100g) and total antioxidant activity (46.84µmol trolox equiv./100g) were found highest in beans produced under organic mulch. Overall results demonstrated that crop mulching could be used for enhancing the antioxidants, phenolic content of cowpea beans.

scholarly journals PENGARUH UMUR DAUN TEH DAN WAKTU OKSIDASI ENZIMATIS TERHADAP KANDUNGAN TOTAL FLAVONOID PADA TEH HITAM (Camellia sinesis)

2021 ◽  
Vol 10 (1) ◽  
pp. 41
Author(s):  
Jennifer Larisa Liem ◽  
Maria Marina Herawati
Keyword(s):  
Black Tea ◽  
Total Flavonoid ◽  
Enzymatic Oxidation ◽  
Average Level ◽  
Flavonoid Compound ◽  
Total Flavonoids ◽  
Tea Leaves ◽  
Time Treatment ◽  
Oxidation Stage

Flavonoid compound is an important compound of tea products. However, the flavonoid level content in black tea is lowest than other teas. This is due to the processing of black tea which has an enzymatic oxidation stage and  the tea age leaves when picking. Young tea leaves contain higher total flavonoids than old tea leaves. With an average level of total flavonoids, the young tea leaves is 27.76% qe w / w, while for the old tea leaves 18.61% qe w / w. However, the enzymatic oxidation time treatment did not affect the total flavonoids because the process only affected the quality of black tea steeping, on it’s colour, aroma, and taste. Keywords: age of tea leaves, black tea, enzymatic oxidation, total flavonoids

scholarly journals Changes in Phytochemicals and Determination of Optimum Fermentation Time during Black Tea Manufacturing

2020 ◽  
Vol 12 (4) ◽  
pp. 657-664
Author(s):  
M. M. Rahman ◽  
M. M. Hossain ◽  
R. Das ◽  
I. Ahmad
Keyword(s):  
Black Tea ◽  
Quality Parameters ◽  
Biochemical Changes ◽  
Enzymatic Oxidation ◽  
Time Intervals ◽  
Fermentation Time ◽  
Tea Quality ◽  
Processing Steps

Black tea processing consists of four steps, namely withering, CTC, fermentation and drying, while cup quality made tea mostly controlled by fermentation step. This study evaluated biochemical changes at different stages of black tea processing in Bangladesh and determined the optimum fermentation time. Samples were collected from different tea processing stages to measure major phytochemicals and time intervals during fermentation to measure theaflavins and thearubigins ratio. Caffeine content was the least susceptible to processing steps. Biochemical changes started at withering, cell maceration and enzymatic oxidation started at CTC processing, thus the major reduction in the reducing sugar (20.46 to 04.95 ppm), catechin (16.88 to 7.95 ppm) and polyphenol (42.30 to 30.73 ppm) occurred here. The significant changes appeared during fermentation when polyphenol content decreased from 44.66 to 18.23 and catechin from 17.41 to 03.98 ppm due to the breakdown of these compounds to theaflavins (TF) and thearubigins (TR). The TF and TR ratio increased with fermentation time, and the highest of 1:8.4 was found at 50 min, which turned into 1:10 in the final product. The made tea quality parameters were comparable or better at fermentation time of 50 min than the quality of the black tea available in market.

scholarly journals Effect of Brewing Method on Quality Parameters and Antioxidant Capacity of Black Tea

2021 ◽  
Vol 1 (8) ◽  
pp. 1
Author(s):  
Zeynep B. Guzel-Seydim ◽  
Atif Can Seydim ◽  
Annel K. Greene
Keyword(s):  
Antioxidant Capacity ◽  
Phenolic Content ◽  
Black Tea ◽  
Quality Parameters ◽  
Total Phenolic ◽  
Tea Leaves ◽  
Total Polyphenols ◽  
Brewing Method ◽  
Functional Components ◽  
Brewing Time

Introduction: The traditional method for brewing tea in Turkey involves use of a two-vessel apparatus known as a “caydanlik.” The caydanlik allows for tea to be brewed for a longer time than typical brewing methods and involves introducing boiling water to tea leaves and steeping them in a teapot as the temperature declines over 15 minutes. In comparison, the typical tea brewing method used in other parts of the world involves steeping tea leaves in a single vessel teapot for 5 minutes. This study evaluated the effects of these two methods of brewing using two brands of tea.  Results: Results of this experiment indicate that use of the caydanlik and the accompanying longer brewing time significantly changed key quality parameters and increased the antioxidant capacity of the brewed black tea beverage. Use of the caydanlik method resulted in significantly higher (P < 0.05) theaflavins, thearubigins, theabrownins, and total polyphenols in the resultant tea than in tea brewed in a traditional teapot. Additionally, analysis of color values of the brewed tea indicated the L and b-values were significantly (P < 0.05) lower in the caydanlik brewed tea while a and hue values were significantly higher (P < 0.05). However, chroma values were not significantly different (P < 0.05) between the two methods.   Conclusions: In addition to influencing color, flavor and aroma, the brewing method also influenced the functional properties of prepared black tea. Use of the traditional two-vessel caydanlik for tea preparation increased concentrations of beneficial functional components in the tea.Keywords: Black tea, Caydanlik, Brewing, Camelia sinensis, ORAC, Total Phenolic Content 

scholarly journals Absolute Quantitative Volatile Measurement from Fresh Tea Leaves and the Derived Teas Revealed Contributions of Postharvest Synthesis of Endogenous Volatiles for the Aroma Quality of Made Teas

2021 ◽  
Vol 11 (2) ◽  
pp. 613
Author(s):  
Mingjie Chen ◽  
Li Guo ◽  
Huiwen Zhou ◽  
Yaling Guo ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Black Tea ◽  
Significant Loss ◽  
Tea Leaves ◽  
Gene Expressions ◽  
Flame Ionization ◽  
Tea Quality ◽  
Different Types ◽  
Aroma Characteristics ◽  
Volatile Profiles

Characteristic aroma is a well-appreciated feature contributing to tea quality. Although extensive studies have been made to investigate aroma biosynthesis and gene expressions during tea making processes, it remains unclear whether the endogenous volatile biosynthesis during postharvest tea processing contributes to the aroma quality of made tea. To critically evaluate this question, we used the same batch of fresh tea leaves and produced three different types of tea with different degrees of fermentation (green tea, oolong tea, and black tea). Total volatiles were extracted by solvent-assisted-flavor evaporation, then quantified by gas chromatography-flame ionization detector combined with response factor correction for quantitative measurement. Compared with fresh tea leaves, the volatile profiles of the made teas were dramatically altered, with significant loss for the majority of endogenous volatiles and simultaneous gain for non-endogenous volatiles. By calculation of odor-activity values, the potential volatiles contributing to the aroma characteristics of each tea type were identified. Our data suggest that postharvest synthesis of endogenous volatiles did not contribute to the aroma quality of made tea.

Clonal Variations in the Response of Hard Physically Withered Leaf to Rehydration Following Long Chemical Wither Durations

2017 ◽  
Vol 13 (01-02) ◽  
Author(s):  
P. Okinda Owuor ◽  
Martin Obanda
Keyword(s):  
Black Tea ◽  
Quality Parameters ◽  
Tea Plant ◽  
Oxidative Enzymes ◽  
Quality Deterioration ◽  
Tea Quality ◽  
Genetic Makeup

Long chemical wither durations and hard physical wither reduce the quality of plain black tea, through reduction in total theaflavins production while encouraging thearubigins formation. Such quality reduction may vary with genetic makeup of the tea plant. However, rehydration reactivates activities of oxidative enzymes responsible for producing plain black tea quality parameters. Influence of rehydrating hard physically withered leaf that had undergone long chemical wither durations on two clonal plain black tea quality parameters were assessed. Rehydration restored the formation of plain tea quality parameters from hard physically withered leaf. However, quality deterioration due to long chemical wither duration could not be reversed by rehydration. The patterns of responses of the clones used were similar. Thus in the processing of plain black tea, efforts should be made to maintain chemical wither durations to below 30 hours. However, rehydration reverses reduced plain black tea quality parameters by hard physical withers to equivalent of chemical wither

scholarly journals Effect of Fermentation Conditions and Plucking Standards of Tea Leaves on the Chemical Components and Sensory Quality of Fermented Juice

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ping Tang ◽  
Dan-Yu Shen ◽  
Yong-Quan Xu ◽  
Xing-Cai Zhang ◽  
John Shi ◽  
...  
Keyword(s):  
Sensory Quality ◽  
Black Tea ◽  
Chemical Components ◽  
Tea Leaves ◽  
Time Duration ◽  
Essential Information ◽  
Fermentation Conditions ◽  
Overall Acceptability ◽  
Fermented Juice

The effects of fermentation conditions (temperature, time, and pH) and plucking standards (one leaf and a bud to four leaves and a bud) on the chemical components and sensory quality of the fermented juices processed from crushed fresh tea leaves were investigated. The results showed that optimum fermentation conditions that resulted in fermented juices of the best sensory quality and the highest content of TFs were a temperature of 35°C, time duration of 75 min, and pH 5.1. The fermented juices processed from new shoots with three leaves and a bud or four leaves and a bud afforded high overall acceptability and TF concentration. These differences arise because tea leaves with different plucking standards have different catechin content and enzyme activities. Fermented tea juice possessed higher concentrations of chemical components such as soluble solids, amino acids, and TFs and exhibited better sensory quality as compared to black tea infusion. The TF concentrations decreased as the pH of the fermenting juice increased, and the fermented juice showed the best overall acceptability. These results provide essential information for the improvement of the processing of black tea beverage by suggesting fermentation of fresh tea leaves as a better alternative to their infusion.

scholarly journals Enhancement of Black Tea Aroma by Adding the β-Glucosidase Enzyme during Fermentation on Black Tea Processing

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Supriyadi Supriyadi ◽  
Alfrista Ruri Nareswari ◽  
Aprilia Fitriani ◽  
Rachmad Gunadi
Keyword(s):  
Volatile Compound ◽  
Methyl Salicylate ◽  
Sodium Citrate ◽  
Black Tea ◽  
Tea Leaves ◽  
Citrate Buffer ◽  
Sodium Citrate Buffer

Black tea aroma is one of the essential attributes in determining the quality of black tea. β-Glucosidases were investigated for their ability to enhance the aroma of black tea by hydrolyzing the glycoside compound. The addition of β-glucosidase was done by dissolving the enzyme on a sodium citrate buffer (pH 5.0), which was then sprayed on tea leaves during black tea processing. The β-glucosidase treatment significantly increases the volatile compound from glycoside precursors such as linalool, geraniol, and methyl salicylate. Moreover, the volatile compound from carotenoid and lipid precursors (nerolidol and β-cyclocitral) was also increased with β-glucosidase treatment.

Effects of withering on the main physical properties of withered tea leaves and the sensory quality of congou black tea

2019 ◽  
Vol 51 (3) ◽  
pp. 542-553
Author(s):  
Yulong Ye ◽  
Chunwang Dong ◽  
Fan Luo ◽  
Jilai Cui ◽  
Xueli Liao ◽  
...  
Keyword(s):  
Physical Properties ◽  
Sensory Quality ◽  
Black Tea ◽  
Tea Leaves

scholarly journals The Effects of Pre-Ozonation on Drinking Water Quality Parameters

2021 ◽  
Vol 7 (1) ◽  
pp. 70-83
Author(s):  
Bahman Masoomi ◽  
◽  
Neamatollah Jaafarzadeh ◽  
Tayebeh Tabatabaie ◽  
Sahand Jorfi ◽  
...  
Keyword(s):  
Contact Time ◽  
Pilot Scale ◽  
Quality Parameters ◽  
Lower Amount ◽  
Alkaline Ph ◽  
Water Contact ◽  
Sample Water ◽  
Process Factors ◽  
Indirect Relationship

The study investigated the effects of pre-ozonation on the parameters such as turbidity, color, chlorophyll a and TOC on a pilot scale. The investigation results indicate that the amount of required ozone to remove TOC, color and turbidity depends on the quality of inlet water, and the efficiency of water ozonation depends on the process factors such as ozone dose, temperature, pH and ozone-water contact time. The study likewise shows that the lower amount of turbidity, TOC, temperature and higher alkaline pH of sample water boost the ozonation effect on removing the variables in question. The results also demonstrate a direct relationship between pH, ozone dosage and contact time, as well as an indirect relationship between temprerature and the removal of parameters.

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