Introduction
In the tea market, "organic tea" often comes with the label of "healthier and higher quality", but is its quality truly superior to conventionally grown tea? Recently, a research team from Bangladesh published a research paper titled "Quality Assessment of Organic and Conventional Black Tea in Different Seasons" in the journal "Measurement: Food" , which systematically compared the quality parameters of the two types of black tea.
Research Results
I. Regular Tea VS Organic Tea
Conventional tea tree cultivation has long relied on chemical fertilizers and pesticides, which not only may lead to soil degradation but also affect the natural quality of tea. In contrast, organic tea, by avoiding the use of synthetic chemicals, is more in line with the concept of ecological sustainability, yet it is limited by low yield and high cost, making its promotion more difficult.
Figure 1 Experimental Design
To verify the quality advantages of organic tea, the research team selected organic and conventional tea gardens in the same region , with the same tea variety as the research object, sampling quarterly from March to December to comprehensively compare the differences between the two.
The results showed that: Regardless of the season, organic tea consistently outperforms traditional tea in key quality indicators such as total polyphenols, theaflavins, thearubigins, and antioxidant activity. Even though some parameters fluctuate seasonally, the quality advantage of organic tea has never changed.
II. Comparison of Quality Parameters
1. Basic quality parameters: moisture, ash, and lipid.
Both have a moisture content below 5%, meeting the tea storage standard; their lipid contents are both below 5%, with no risk of rancidity.
Figure 2 Comparison of moisture and ash content indicators for samples of conventional tea (blue) and organic tea (orange) collected in March, June, September, and December
Ash represents mineral residue and is a key indicator for measuring tea quality. Higher ash content often indicates higher maturity of fresh leaves or lower tea quality.
The research results show that the ash content of conventional tea is higher, reaching a maximum of 7.64% (sampled in March), while that of organic tea is 5.46%, indicating that conventional tea is richer in minerals.
|
Parameter
|
Tea Type
|
Mar
|
Jun
|
Sep
|
Dec
|
|---|---|---|---|---|---|
|
Moisture and Ash (%)
|
Regular tea
|
3.0
|
3.1
|
3.2
|
3.0
|
|
Organic Tea
|
2.4
|
3.0
|
3.5
|
3.4
|
Table 1 Comparison of Moisture and Ash Content Indicators between Conventional Tea and Organic Tea Sampled in March, June, September, and December
2. Sensory quality parameters: water extract, highly polymerized substances, and total soup color.
The water extract content of organic tea is 33.73%-36.17%, higher than that of conventional tea, which is 29.33%-30.74%.
Figure 3 Comparison of water extract indicators for samples of regular tea (blue) and organic tea (orange) collected in March, June, September, and December
Water extracts contain soluble components such as tea polyphenols and amino acids, which directly affect the taste and richness of tea soup. The higher the content, the richer the taste when drinking.
|
Parameter
|
Tea Type
|
Mar
|
Jun
|
Sep
|
Dec
|
|---|---|---|---|---|---|
|
Water-soluble extractives (%)
|
Regular tea
|
29.5
|
31.2
|
30.5
|
32.0
|
|
Organic Tea
|
34.5
|
33.0
|
36.0
|
34.0
|
Table 2 Comparison of Water Extract Indexes of Conventional Tea and Organic Tea Sampled in March, June, September, and December
The high polymer substance (HPS) content of organic tea is 4.25%-7.37%, lower than that of conventional tea (7.41%-9.02%). Excessive high polymer substance can cause tea soup to become cloudy, and the lower high polymer substance in organic tea makes the tea soup clearer and more transparent.
The total liquor color value (TLC) of organic tea reaches up to 4.25%, higher than the 3.17% of traditional tea, indicating that it has a richer liquor color and a better visual experience.
|
Parameter
|
Tea Type
|
Mar
|
Jun
|
Sep
|
Dec
|
|---|---|---|---|---|---|
|
HPS (%)
|
Regular tea
|
7.41 ± 0.56<sup>A,b</sup>
|
8.06 ± 0.76<sup>A,ab</sup>
|
9.02 ± 0.15<sup>A,a</sup>
|
7.93 ± 0.41<sup>A,b</sup>
|
|
Organic Tea
|
6.17 ± 0.21<sup>B,ab</sup>
|
7.37 ± 1.34<sup>A,a</sup>
|
4.25 ± 0.39<sup>B,c</sup>
|
5.40 ± 1.29<sup>A,bc</sup>
|
|
|
TLC (%)
|
Regular tea
|
2.23 ± 0.30<sup>B,b</sup>
|
3.17 ± 0.20<sup>B,a</sup>
|
2.66 ± 0.43<sup>A,ab</sup>
|
2.92 ± 0.25<sup>A,a</sup>
|
|
Organic Tea
|
3.07 ± 0.09<sup>A,b</sup>
|
4.25 ± 0.26<sup>A,a</sup>
|
2.04 ± 0.07<sup>A,c</sup>
|
2.13 ± 0.17<sup>B,c</sup>
|
Table 3 Comparison of High Polymer Substances and Total Liquor Color Value (HPS, TLC) Indicators of Conventional Tea and Organic Tea Sampled in the Third, Sixth, Ninth, and Twelfth Months
III. Differences in Nutritional Indicators
1. Tea Polyphenols
Polyphenols are the core of the antioxidant, anti-inflammatory, and other health benefits of tea. Research has found that the total polyphenol content of organic tea reaches 31.36%-35.03%, which is 2-3 times that of traditional tea (9.29%-14.43%).
Figure 4 Comparison of total polyphenol indicators for samples of regular tea (blue) and organic tea (orange) collected in March, June, September, and December
|
Parameter
|
Tea Type
|
Mar
|
Jun
|
Sep
|
Dec
|
|---|---|---|---|---|---|
|
Antioxidant activity (%)
|
Regular tea
|
93.2
|
92.4
|
94.1
|
91.8
|
|
Organic Tea
|
94.1
|
93.8
|
95.1
|
92.1
|
Table 4 Comparison of Total Polyphenol Indexes of Conventional Tea and Organic Tea Sampled in March, June, September, and December
2. Thearubigins, Theaflavins
The theaflavin (TF) content of organic tea is 0.91%-0.98%, and the thearubigin (TR) content is 8.52%-9.89%, both of which are significantly higher than those of traditional tea (TF: 0.70%-0.82%; TR: 5.84%-8.36%). These two substances are key products of black tea fermentation. Theaflavin enhances the freshness and brightness of tea soup, and can strengthen antioxidant and antibacterial abilities; Thearubigin determines the color and concentration of tea soup, and has been proven to have potential anti-cancer effects.
|
Parameter
|
Mar
|
Jun
|
Sep
|
Dec
|
|
|---|---|---|---|---|---|
|
TF (%)
|
Regular tea
|
0.70 ± 0.01<sup>B,b</sup>
|
0.82 ± 0.03<sup>A,a</sup>
|
0.78 ± 0.07<sup>B,ab</sup>
|
0.74 ± 0.04<sup>B,ab</sup>
|
|
Organic Tea
|
0.92 ± 0.06<sup>A,a</sup>
|
0.91 ± 0.07<sup>A,a</sup>
|
0.98 ± 0.05<sup>A,a</sup>
|
0.91 ± 0.04<sup>A,a</sup>
|
|
|
TR (%)
|
Regular tea
|
5.84 ± 0.56<sup>B,c</sup>
|
7.11 ± 0.14<sup>B,b</sup>
|
8.36 ± 0.44<sup>B,a</sup>
|
7.36 ± 0.28<sup>A,b</sup>
|
|
Organic Tea
|
9.70 ± 0.23<sup>A,a</sup>
|
8.52 ± 0.36<sup>A,b</sup>
|
9.89 ± 0.53<sup>A,a</sup>
|
9.22 ± 0.96<sup>A,ab</sup>
|
|
|
TF:TR
|
Regular tea
|
1:8.34
|
1:8.67
|
1:10.72
|
1:9.95
|
|
Organic Tea
|
1:10.54
|
1:9.36
|
1:10.09
|
1:10.13
|
Table 5 Comparison of Theaflavin and Thearubigin Indicators of Conventional Tea and Organic Tea Sampled in March, June, September, and December
Moreover, the ratio of theaflavins to thearubigins in organic tea is mostly around 1:10, approaching the ideal quality standard. This indicates that, although theaflavins and thearubigins are produced during the oxidation process, the cultivation system still affects their formation, because the main substrate for tea pigment production, catechins, is influenced by the cultivation system.
3. Antioxidant Activity
The research team further compared the antioxidant activities of conventional tea and organic tea, and the results showed that both performed excellently, but organic tea always had a slight edge.
|
Parameter
|
Tea Type
|
Mar
|
Jun
|
Sep
|
Dec
|
|---|---|---|---|---|---|
|
Antioxidant activity (%)
|
Regular tea
|
93.2
|
92.4
|
94.1
|
91.8
|
|
Organic Tea
|
94.1
|
93.8
|
95.1
|
92.1
|
Table 6 Comparison of Antioxidant Activity Indicators of Conventional Tea and Organic Tea Sampled in March, June, September, and December
Conclusion
This study confirms that although the yield of organic tea is 22% lower than that of conventional tea and its cultivation cost is higher, it performs better in terms of health-active ingredients, sensory experience, basic quality, etc.
Organic farming, by avoiding synthetic chemicals and adopting organic fertilizers and biological pest control methods, not only protects soil ecosystem and human health but also allows the natural quality of tea to be fully released.
To ensure the accuracy and traceability of information, the viewpoints and data in this article are cited from "New National Tea Research Laboratory"'s "Is Organic Tea Really of Higher Quality? This CTC Black Tea Study Tells You the Answer"https://mp.weixin.qq.com/s/98QY4YkkvjpXmWF9R4GKng?scene=1, hereby stated and thanked.
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