How Heat Processing Impacts Quality and Health Compounds in Ginkgo Leaf Tea

Jenn Hoskins
25th May, 2024

How Heat Processing Impacts Quality and Health Compounds in Ginkgo Leaf Tea

Image Source: Natural Science News, 2024

Key Findings

  • The study by Jiangsu University, China, explored thermal fixation methods to produce safer Ginkgo biloba dark tea (GBDT)
  • Both boiled water fixation (BWF) and hot air fixation (HAF) significantly reduced toxic ginkgolic acids by 41.1% and 34.6%, respectively
  • Hot air fixation (HAF) was the most effective method, enhancing beneficial properties like reducing sugar, free amino acids, total phenolic content, and antioxidant activities
Ginkgo biloba leaves (GBLs) are known for their high content of beneficial phytochemicals, yet their application is limited due to the presence of toxic ginkgolic acids (GAs). A recent study by Jiangsu University, China, explored the use of thermal fixation techniques to produce Ginkgo biloba dark tea (GBDT), aiming to reduce these toxic compounds while retaining the beneficial bioactive components[1]. This study holds promise for enhancing the safety and quality of GBL products, potentially broadening their use. The research team investigated three thermal fixation methods: hot air fixation (HAF), iron pot fixation (IPF), and boiled water fixation (BWF), followed by rolling, fermentation, and drying processes to produce GBDT. The study comprehensively analyzed the impact of these methods on the levels of toxicants (GAs), bioactive compounds (such as ginkgolides, bilobalide, and flavonoids), and overall product quality, including moisture content, reducing sugar (RS), free amino acids (FAAs), enzyme activity, color properties, and antioxidant capacity. The findings revealed that both BWF and HAF significantly reduced GA contents by 41.1% and 34.6%, respectively. This reduction in toxic components is crucial as it addresses a significant barrier to the broader application of GBLs. The study also showed that the control group (unfixated) had the highest levels of toxic components, terpene trilactones, and total flavonoid content (TFC) compared to the treated samples. Among the different thermal fixation methods, HAF emerged as the most effective. It yielded the best results in terms of RS, FAA, total phenolic content, and antioxidant activities. This suggests that HAF not only reduces toxic components but also enhances the beneficial properties of GBDT. IPF, on the other hand, resulted in the highest TFC, while BWF had the lowest GA content, indicating that each method has unique advantages depending on the desired outcome. The study's findings align with previous research on the drying and processing of Ginkgo biloba seeds. For instance, infrared drying has been shown to reduce toxic compounds such as ginkgotoxin, ginkgolic acid, and cyanide in Ginkgo biloba seeds, while also enhancing antioxidant activities and bioactive compound content[2]. This highlights the potential of specific processing techniques to improve the safety and quality of Ginkgo biloba products. Furthermore, the study on nonthermal pretreatments and infrared drying of Ginkgo biloba seeds demonstrated that ultrasound (US) pretreatment significantly improved mass transfer, drying rate, and energy efficiency[3]. This indicates that combining appropriate pretreatments with effective drying methods can optimize the processing of Ginkgo biloba products, potentially making them more commercially viable. In the context of tea production, drying is a critical step that affects the chemical composition and quality of the final product. Research on the drying of coffee leaves has shown that high-temperature short-time drying helps retain phenolic compounds and antioxidant activity, while prolonged drying can lead to quality degradation[4]. These insights are relevant to the current study as they underscore the importance of optimizing drying conditions to preserve the beneficial properties of GBDT. In conclusion, the study by Jiangsu University offers valuable insights into the processing of Ginkgo biloba leaves to produce high-quality, safe GBDT. The use of thermal fixation methods, particularly HAF, effectively reduces toxic components while preserving and enhancing beneficial bioactive compounds. These findings, in conjunction with earlier research on drying and pretreatment techniques, provide a comprehensive understanding of how to optimize the processing of Ginkgo biloba products for broader applications.

HealthBiochemPlant Science

References

Main Study

1) Thermal fixation technologies affect phenolic profile, ginkgolides, bilobalide, product quality, and ginkgolic acids in Ginkgo biloba leaf tea.

Published 23rd May, 2024

https://doi.org/10.1111/1750-3841.17126

Related Studies

2) Effect of different drying methods on product quality, bioactive and toxic components of Ginkgo biloba L. seed.

https://doi.org/10.1002/jsfa.10958

3) Osmotic, osmovacuum, sonication, and osmosonication pretreatment on the infrared drying of Ginkgo seed slices: Mass transfer, mathematical modeling, drying, and rehydration kinetics and energy consumption.

https://doi.org/10.1111/1750-3841.15916

4) Effects of hot-air drying on the bioactive compounds, quality attributes, and drying and color change kinetics of coffee leaves.

https://doi.org/10.1111/1750-3841.16431


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