Does green tea go bad?
Author bio
Dr Anny Manrich PhD is a food Engineer with expertise in Food Technology, Natural Polymers, Edible Films, Enzymes, and Nanotechnology. She writes and reviews content on these topics.
Dr Anny Manrich’s Highlights:
- Research and Technology at the Brazilian Agricultural Research Corporation
- PhD in Chemical Engineering with a focus on Biochemistry at the Federal University of Sao Carlos/ Brazil and a one-year scholarship at the Technical University of Munich/ Germany
- Bachelor of Food Engineering at the University of Campinas/ Brazil and a one-year scholarship at the Technical University of Munich/ Germany
“To solve a problem, global vision and multifactorial understanding are necessary. Therefore, in addition to expertise, one should seek multidisciplinary thinking connected with science and reality” – Dr Anny Manrich, PhD.
Professional Experience:
Dr Anny Manrich’s Experience Joining the Brazilian Agricultural Research Corporation, as soon as she completed her doctorate,
Dr Anny Manrich has worked on several projects, including the more than three-year partnership project with BRF, a major food producer in Brazil. As a postdoctoral fellow.
Dr Anny Manrich has also contributed to several business consultancies and research projects of the National Nanotechnology Laboratory System in areas such as food technology, fibres, films and coatings and Nanotechnology; in a very determined way, having a great team relationship, being creative and committed.
Growing concerns about the safe introduction of nanomaterials into today’s life emphasises the need to create regulatory documentation in front of characterising, using and testing them. Dr Anny Manrich worked for two years on a characterization project for nanoscale materials, with the aim of exploring their possible health effects.
Despite not having specific academic training in packaging or polymeric films, Dr Anny Manrich works at the Brazilian Agricultural Research Corporation in areas of edible and biodegradable films produced from agricultural waste and in the development of films with greater resistance to water, having articles published in renowned scientific journals, which demonstrates her multidisciplinary understanding and creativity.
In addition, she worked for four years as a consultant to a food company to develop a line of snacks that are healthy and that add functional ingredients, physiologically active compounds that bring health benefits, made from fruits and vegetables, enabling diet improvement, disease prevention and reduction of nutritional deficiencies.
Dr Anny Manrich participated as a member of the examination board for two Master’s exams and one PhD exam at the Department of Chemical Engineering of the Federal University of São Carlos.
Education:
- 2001 Bachelor in Food Engineering at the State University of Campinas, Brazil
- 1999 One year scholarship at the Technical University of Munich
- 2004 Master in Chemical Engineering at the Federal University of São Carlos, Brazil
- 2012 PhD in Chemical Engineering at the Federal University of São Carlos, Brazil
- 2010 One year scholarship at the Technical University of Munich
The main publications of Dr. Anny Manrich are:
Articles
Manrich, A., Moreira, F. K., Otoni, C. G., Lorevice, M. V., Martins, M. A., & Mattoso, L. H. (2017). Hydrophobic edible films made up of tomato cutin and pectin. Carbohydrate Polymers, 164, 83-91.
Mendes, J. F., Norcino, L. B., Martins, H. H. A., Manrich, A., Otoni, C. G., Carvalho, E. E. N., … & Mattoso, L. H. C. (2020). Correlating emulsion characteristics with the properties of active starch films loaded with lemongrass essential oil. Food Hydrocolloids, 100, 105428.
Norcino, L. B., Mendes, J. F., Natarelli, C. V. L., Manrich, A., Oliveira, J. E., & Mattoso, L. H. C. (2020). Pectin films loaded with copaiba oil nanoemulsions for potential use as bio-based active packaging. Food Hydrocolloids, 106, 105862.
Manrich, Anny, et al. Immobilization of trypsin on chitosan gels: Use of different activation protocols and comparison with other supports. International Journal of Biological Macromolecules 43.1 (2008): 54-61.
Manrich, Anny; Komesu, Andrea ; Adriano, Wellington Sabino; Tardioli, Paulo Waldir ; Giordano, Raquel Lima Camargo . Immobilization and Stabilization of Xylanase by Multipoint Covalent Attachment on Agarose and on Chitosan Supports. Applied Biochemistry and Biotechnology, v. 161, p. 455-467, 2010.
Mendes, J. F., Martins, J. T., Manrich, A., Neto, A. S., Pinheiro, A. C. M., Mattoso, L. H. C., & Martins, M. A. (2019). Development and physical-chemical properties of pectin film reinforced with spent coffee grounds by continuous casting. Carbohydrate polymers, 210, 92-99..
Milessi, T. S., Kopp, W., Rojas, M. J., Manrich, A., Baptista-Neto, A., Tardioli, P. W., … & Giordano, R. L. (2016). Immobilization and stabilization of an endoxylanase from Bacillus subtilis (XynA) for xylooligosaccharides (XOs) production. Catalysis Today, 259, 130-139.
Mendes, J. F., Norcino, L. B., Manrich, A., Pinheiro, A. C. M., Oliveira, J. E., & Mattoso, L. H. C. (2020). Development, physical‐chemical properties, and photodegradation of pectin film reinforced with malt bagasse fibers by continuous casting. Journal of Applied Polymer Science, 137(39), 49178.
Mendes, J. F., Martins, J. T., Manrich, A., Luchesi, B. R., Dantas, A. P. S., Vanderlei, R. M., … & Martins, M. A. (2021). Thermo-physical and mechanical characteristics of composites based on high-density polyethylene (HDPE) e spent coffee grounds (SCG). Journal of Polymers and the Environment, 29, 2888-2900..
Mendes, J. F., Norcino, L. B., Martins, H. H., Manrich, A., Otoni, C. G., Carvalho, E. E. N., … & Mattoso, L. H. C. (2021). Development of quaternary nanocomposites made up of cassava starch, cocoa butter, lemongrass essential oil nanoemulsion, and brewery spent grain fibers. Journal of Food Science, 86(5), 1979-1996.
Manrich, A., Martins, M. A., & Mattoso, L. H. C. (2021). Manufacture and performance of peanut skin cellulose nanocrystals. Scientia Agricola, 79.
Nascimento, V. M., Manrich, A., Tardioli, P. W., de Campos Giordano, R., de Moraes Rocha, G. J., & Giordano, R. D. L. C. (2016). Alkaline pretreatment for practicable production of ethanol and xylooligosaccharides. Bioethanol, 2(1)..
Manrich, Anny, de Oliveira, J. E., Martins, M. A., & Mattoso, L. H. C. Physicochemical and Thermal Characterization of the Spirulina platensis. J. Agric. Sci. Technol. B, v. 10, p. 298-307, 2020.
Book Chapter
Terra, I. A. A., Aoki, P. H., Delezuk, J. A. D. M., Martins, M. A., Manrich, A., Silva, M. J., … & Miranda, P. B. (2022). Técnicas de Caracterização de Polímeros. Nanotecnologia Aplicada a Polímeros, 614.
Conference Papers
Ferreira, L. F., Luvizaro, L. B., Manrich, A., Martins, M. A., Júnior, M. G., & Dias, M. V. (2017). Comparação da estabilidade de suspensões poliméricas de amido/tocoferol e quitosana/tocoferol. In: CONGRESSO BRASILEIRO DE POLÍMEROS, 14., 2017, Águas de Lindóia, SP.
Manrich, A., Hubinger, S. Z., & Paris, E. C. (2017). Citotoxicidade causada por nanomateriais: avaliação do micronúcleo. In: WORKSHOP DA REDE DE NANOTECNOLOGIA APLICADA AO AGRONEGÓCIO, 9., 2017, São Carlos. Anais… São Carlos: Embrapa Instrumentação, 2017. p. 655-658.
Manrich, Anny, et al. Immobilization and Stabilization of Xylanase by multipoint covalent attachment on Glyoxyl Agarose Support. The 31st Symposium on Biotechnology for Fuels and Chemicals. 2009.
Manrich, Anny, et al. Application of immobilized xylanase on hydrolysis of soluble wood hemicelluloses after using microwave and organosolv pre-treatments. The 32nd Symposium on Biotechnology for Fuels and Chemicals. 2010.
You can view some of Dr Anny’s work below and links to her professional profile.
Research Gate: https://www.researchgate.net/profile/Anny-Manrich-2
Scopus: https://www.scopus.com/authid/detail.uri?authorId=23103497100
Google Scholar: https://scholar.google.com/citations?hl=en&user=Ea9qpr0AAAAJ
Linkedin: https://br.linkedin.com/in/anny-manrich-20693129
In this brief guide, we are going to answer the question “does green tea go bad” with an in-depth analysis of the lifespan of green tea. Moreover, we are going to discuss the proper way to store green tea and the factors that affect the freshness of the tea leaves.
Matcha is considered a special sort of powdered green tea produced in Japan. After the Second World War, the rapid westernization of the Japanese lifestyle and diet led to a further fall in the consumption of matcha. Consequently, by 2016, ceremonial-grade matcha accounted for only 3.3% of green tea production in Japan (1).
So without much ado, let’s dive in and figure out more about it.
Does green tea go bad?
Yes, green tea does go bad after a certain time and as compared to other types of tea the shelf life of green tea is the shortest as it is an unfermented tea as in the world of teas the rule is “The more fermented the tea is, the longer will it last”. Almost all the green tea varieties are unroasted therefore they are the most volatile ones and have the shortest shelf life among all other types of teas.
Green teas contain higher content of catechins [(−)-epigallocatechin gallate, (−)-epigallocatechin, (−)-epicatechin gallate, and (−)-epicatechin] than both Oolong, pu-erh and black teas because fermentation process during the tea manufacturing reduced the levels of catechins significantly (2). For this reason, the chemical compounds in green tea are more susceptible to oxidation. This oxidation occurred during the production process, in the case of black tea. It was reported that tea catechins are not stable during long-term storage. During 6 months’ storage of green tea bags in their original containers at room temperature in the dark, the average content of EGCG decreased by one-third and ECG decreased by half (3).
It is recommended to use the green tea within 6 months after it is purchased to enjoy its premium fresh flavors as it is the peak quality time of the green tea. Nevertheless, green tea can last for about 1 year if it is kept properly in an air-tight container in a cool, dry, and dark place. However, there will be losses of antioxidants and aroma.
But when it comes to matcha, which is a powdered green tea variant it is recommended to use it within 1-2 months of opening. According to studies, the catechin degradation correlated with increasing aw and Tg , i.e. water mobility. Storage at aw 0.75 had the highest impact on catechins stability; the amount of catechins decreased by 39% after the food powder was stored at this condition for 45 days (4).
How to properly store the green tea?
The proper way to store green tea is to keep it in an air-tight container, jar, or air-tight bag in a cool, dry, and dark place. It should be noted that the place should not be humid or else the humidity of the environment can decrease the shelf life of the green tea (3).
When green tea is exposed to the moisture there are great chances of mold formation on it and it will go bad afterward. Moreover, it should also be stored away from direct sunlight. So a cool, dark corner of your pantry will be a good place to store your green tea.
You should always seal the pouch after scooping out the green tea. Moreover, you should never use a wet spoon to scoop out the tea from the package or the container in which it is stored.
You can read more about how to store tea leaves here.
What are the factors that affect the freshness of the tea leaves?
The factors that determine how long the tea leaves will stay fresh include the level of dryness, processing, oxidation, and roasting.
Level of dryness
The shelf life of the tea leaves directly depends upon the extent to which they are dried. If the tea leaves are dried thoroughly then the tea will have a considerably longer shelf life. On the other hand, if the tea leaves are not dried thoroughly then they will have moisture in them because of which they will lose their flavor and aroma quickly and will have a short shelf life. Drying is done to stop the fermentation and to reach the favorable moisture content to suppress microorganism growth (3).
Moreover, if the leaves are kept in a humid environment, then the moisture in the environment will result in mold growth on the leaves. The leaves that have mold growing on it will go bad quickly.
Processing
The more processed the tea leaves are, the easier will it be to dry them thoroughly and the longer will be their shelf life. That means that the shelf life of the black tea is more than that of the green tea as the former is a more processed one.
During green tea processing, the enzymes which catalyze oxidation are deactivated by heat treatment (pan-roasting or steaming), so that more tea catechins are retained. Processing of green tea leaves involving roasting, rolling and drying steps reduce catechins of the tea and stabilize the product, extending its shelf life. In the final product, total catechins are significantly reduced by up to 87% (4).
Oxidation
Oxidation is the process that brings out various flavors in the tea and also plays an important role to stabilize the otherwise volatile flavors and constituents of life. Some of the tea like oolong tea and green tea are the ones that are partially oxidized.
Roasting
Roasting further helps in drying the tea leaves thoroughly, thus it helps to further stabilize the constituents of tea. Roasting also enhances the flavor profile of the tea. When it comes to roasting, every type of tea can be roasted but mainly the oolong tea is the one that is roasted most commonly.
Other FAQs about Tea which you may be interested in.
How does Starbucks make chai tea latte?
What can I do with expired tea leaves?
You can use the expired tea leaves as odor absorbers. You can keep them in your kitchen, fridge, or storage area so that they can absorb the strong odors there.
Moreover, you can also use them as fertilizers for your plants as the tea leaves still have some nutrients left in them. All you gotta do is to crush them and spread them in the soil surrounding your plant.
What happens if you consume expired green tea?
So when it comes to teas, the best before or the expiry time refers to the time after which the tea no longer has its great flavor and aroma. So as long as you are not that concerned about the flavor and aroma of the green tea, you can go for a green tea that is past its prime age, and even if you consume expired green tea, it won’t harm you.
However, tea can be contaminated with microorganisms, such as Aspergillus niger, during storage. The risk associated with tea bags is probably low, as the tea is usually prepared in the kitchen by the addition of boiling water, which likely kills the spores, although this has not been clearly demonstrated (5).
But if there is a mold in your green tea, it is recommended that you should not use it.
Conclusion
In this brief guide, we answered the question “does green tea go bad” with an in-depth analysis of the lifespan of green tea. Moreover, we discussed the proper way to store green tea and the factors that affect the freshness of the tea leaves.
Citations
- Sekine, Kae. The impact of geographical indications on the power relations between producers and agri-food corporations: A case of powdered green tea matcha in Japan. Geographical Indication and Global Agri-Food. Routledge, 2019. 54-69.
- Zuo, Yuegang, Hao Chen, and Yiwei Deng. Simultaneous determination of catechins, caffeine and gallic acids in green, Oolong, black and pu-erh teas using HPLC with a photodiode array detector. Talanta, 2002, 57, 307-316.
- Kosińska, Agnieszka, and Wilfried Andlauer. Antioxidant capacity of tea: effect of processing and storage. Processing and impact on antioxidants in beverages. Academic Press, 2014. 109-120.
- Ananingsih, Victoria K., Amber Sharma, and Weibiao Zhou. Green tea catechins during food processing and storage: A review on stability and detection. Food Res Int, 2013, 50, 469-479.
- Bouakline, Adel, et al. Fungal contamination of food in hematology units. J clin microbiol, 2000, 38, 4272-4273.
