Advances in bioconversion of spent tea leaves to value-added products

Negi, Taru; Kumar, Yogesh; Sirohi, Ranjna; Singh, Shikhangi; Tarafdar, Ayon; Pareek, Sunil; Awasthi, Mukesh Kumar; Sagar, Narashans Alok

doi:10.1016/j.biortech.2021.126409

Cited by 42 publications

(19 citation statements)

References 85 publications

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“…This might be attributed to the high tannin content of STLP. For instance, the tannin content in STLP is generally 3170–12,600 mg/100 g [ 46 ]. The tannin contents in cookies were in the order of BTC (6.10 mg/100 g) > OTC (4.21 mg/100 g) > GTC (2.33 mg/100 g) > CCO (0.28 mg/100 g).…”

Section: Resultsmentioning

confidence: 99%

Utilising Spent Tea Leaves Powder as Functional Ingredient to Enhance the Quality of Non-Gluten Shortbread Cookies

Koh

Lim

Tan

et al. 2023

Foods

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The increasing prevalence of gluten-related disorders has led to higher consumer demand for convenient, gluten-free bakery products with health-promoting properties. In this study, non-gluten shortbread cookies were incorporated with various kinds of spent (green, oolong, and black) tea leaves powder (STLP) at 8% w/w. Cookies with STLP had significantly higher (p < 0.05) moisture (2.18–2.35%), crude fibre (14.5–14.9%), total dietary fibre (22.38–22.59%), insoluble dietary fibre (15.32–15.83%), soluble dietary fibre (7.06–7.66%), and ash (1.9–2.0%) contents, but were significantly lower (p < 0.05) in carbohydrate (53.2–53.9%) and energy value (426.4–428.2 kcal) compared to control cookies (1.62%; 1.43%; 6.82%; 4.15%; 2.67%; 7.70%; 62.2%; and 457.8 kcal, respectively). The addition of STLP significantly enhanced (p < 0.05) the antioxidant properties of the cookies. Non-gluten shortbread cookies with spent green tea leaves powder (GTC) received the highest (p < 0.05) score for all sensory attributes, including overall acceptability. In addition, the shelf-life quality of the formulated cookie samples in terms of the moisture content, water activity, colour, texture, microbiology, and sensory properties was maintained (p > 0.05) for at least 22 days at 25 °C. STLP, which would have been previously thrown away, could be utilized as a potential functional ingredient to produce non-gluten shortbread cookies with enhanced nutritional, physicochemical, microbiological, sensory, and antioxidative properties.

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Section: Resultsmentioning

confidence: 99%

Utilising Spent Tea Leaves Powder as Functional Ingredient to Enhance the Quality of Non-Gluten Shortbread Cookies

Koh

Lim

Tan

et al. 2023

Foods

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“…3 Another major beverage, tea with a global production of 6 million tons, leaves 90% solid residues after processing. 4 These residues from the early stage of the food supply chain have untapped potential for upcycling into merchandised products. Unlike domestic food waste that has complex compositions and is often contaminated by impurities (e.g., plastic utensils), the centralized production of food manufacturing and processing byproducts with relatively uniform quality can facilitate logistics and upcycling.…”

Section: ■ Introductionmentioning

confidence: 99%

Upcycling of Spent Tea Leaves and Spent Coffee Grounds into Sustainable 3D-Printing Materials: Natural Plasticization and Low-Energy Fabrication

Chan

Zhang

et al. 2023

ACS Sustainable Chem. Eng.

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Food processing byproducts are potential filling materials for fabricating sustainable composites with broad applications. We herein report the use of spent coffee grounds (SCG) and spent tea leaves (STL) to prepare biomass/poly(lactic acid) (PLA) composites as novel 3D-printing inks. The results show that the 3D-printability can be upheld at a high biomass loading of 40 wt %. As for strength performance, the biomass addition disrupted the PLA structure and reduced the tensile strength of the 3D-printed specimens. However, elongation at break was enhanced 5-fold at 20 wt % SCG, which could be attributed to the plasticizing effect of the naturally occurring oil in SCG. The SCG oil can be added to STL/ PLA for improved ductility. With little oil (<30 mg/g composite) at ∼20 wt % biomass loading, samples prepared from 155 °C-filament showed higher tensile strength than those at 185 °C. Microscopic imaging evidenced more significant pore formation in the latter, rendering the structure delicate. These findings reveal the complex effects of filler properties on the biomass-PLA interface that determines the composite performance.

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Section: Introductionmentioning

confidence: 99%

“…Among different carbon-rich waste materials, spent tea leaves (STL) and spent coffee grounds (SCG) are one of the most abundant by-products generated worldwide due to high global consumption of tea and coffee, which reached up to 6 and 10 million tons, respectively, in 2020 [14,15]. Huge quantities of solid residues (~90%) of STL and SCG are produced during their brewing for different types of products such as canned, bottled, and instant products [14]. Continuous disposal of these waste products in open field is problematic and may increase anthropogenic gas emission and water and soil pollution owing to the toxic nature of its components, including caffeine, polyphenols, and tannins [15].…”

Section: Introductionmentioning

confidence: 99%

“…Continuous disposal of these waste products in open field is problematic and may increase anthropogenic gas emission and water and soil pollution owing to the toxic nature of its components, including caffeine, polyphenols, and tannins [15]. Notably, STL and SCG are potential energy sources enriched with carbonderivatives such as alkaloids and polyphenols (STL) and organic compounds including fatty acids, hemicelluloses, lignin, cellulose, and other polysaccharides (SCG) [14,15]. Recent studies have highlighted the potential of SCG and STL as a source of sugars [16], bioethanol [17], and biodiesel [18], and some studies have exploring the use of STL and SCG for fabricating electrodes [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

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Spent Tea Leaves and Coffee Grounds as Potential Biocathode for Improved Microbial Electrosynthesis Performance

Tahir

Ali

Kim

et al. 2023

International Journal of Energy Research

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Microbial electrosynthesis (MES) has emerged as a sustainable energy platform capable of simultaneous wastewater treatment and valuable chemical production. The performance of MES, like other bioelectrochemical systems, largely depends on its electrode (cathode), providing the platform for microbial growth as well as electron transfer. However, most of the electrodes are expensive, and their nonrenewable characteristics, cost, and poisoning nature are major bottlenecks in MES commercialization. Thus, several efforts have been made to explore the potential of waste carbon-based electrodes to reduce carbon footprints as well as electrode manufacturing costs. In this study, the feasibility of using spent tea leaves (STL) and spent coffee grounds (SCG) as MES biocathode was tested. Different bioelectrochemical tests suggested improved MES performance with STL and SCG biocathode along with reduced electrode resistance and improved current density. A 1.5- and 2.0-fold increase in cyclic voltammetry (CV) current output was observed for SCG and STL, respectively, with substantial mediator peaks of high intensity indicating enhanced electrocatalytic activity. Enrichment of some fermentative and exoelectrogenic microbial classes such as Clostridia, Bacteroidia, and Deltaproteobacteria led to a 1.3- and 1.4-fold increase in butyrate production for SCG and STL cathode, respectively. These results demonstrate the potential of STL and SCG as MES cathode for improved energy and chemical production.

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Advances in bioconversion of spent tea leaves to value-added products

Cited by 42 publications

References 85 publications

Utilising Spent Tea Leaves Powder as Functional Ingredient to Enhance the Quality of Non-Gluten Shortbread Cookies

Utilising Spent Tea Leaves Powder as Functional Ingredient to Enhance the Quality of Non-Gluten Shortbread Cookies

Upcycling of Spent Tea Leaves and Spent Coffee Grounds into Sustainable 3D-Printing Materials: Natural Plasticization and Low-Energy Fabrication

Spent Tea Leaves and Coffee Grounds as Potential Biocathode for Improved Microbial Electrosynthesis Performance

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