Technological Interventions for Value Addition of Polyherbal Spent Materials from Ayurvedic Industries
This thesis investigates the valorisation of Dashamoola spent material (DSM), a significant waste stream in the Ayurvedic industry. DSM is produced in substantial quantities as a by product of manufacturing Dashamoola concoction, a traditional mixture derived from ten medicinal plants. Building on the premise that DSM contains valuable lignocellulosic biomass (e.g. cellulose and lignin) and health-promoting phenolic compounds, this research explores their extraction, modification, and application in value-added products. Currently discarded as waste, DSM is proposed as a promising source of phenolic compounds, cellulose, and lignin, which could be modified, characterised, and utilised in emulsions, nutrient-rich food formulations, and active packaging.
The introduction chapter establishes the context by highlighting the growing manufacture of Ayurvedic formulations, driven by increasing demand, which has led to a concurrent rise in associated waste streams, including DSM. The lack of effective valorisation of these waste streams is exacerbating environmental challenges and resulting in the underutilisation of a valuable resource. Despite their potential, the Ayurvedic industry has yet to systematically valorise its waste streams to address this issue. This chapter underscores the significance of valorising Ayurvedic waste streams, using DSM as an example to extract, modify, and apply phenolic compounds, cellulose, and lignin as valuable ingredients. This approach aligns with circular economy principles and provides a pathway to address the sustainability concerns of the Ayurvedic industry.
The first experimental chapter focuses on the extraction of phenolic compounds from DSM through an optimised pathway, followed by the identification and characterisation of key compounds. The analyses identified several valuable phenolic compounds in Dashamoola spent material extracts (DSME), including shikimic acid (83.2 mg/g), gallic acid (51.2 mg/g), epicatechin (26.3 mg/g), naringenin (25.0 mg/g), and vanillic acid (14.1 mg/g). The results demonstrated that the DSME possessed significant antioxidant, antidiabetic, and anti 1 inflammatory properties, as evidenced by DPPH data. DSME also showed showed significant anti-inflammatory capability closely matching with that of aspirin. DSME did not show adverse health effects as cell tolerability was up to 500 μg/mL in L6 myoblast and RAW 264.7 cells. These findings highlight DSME’s potential as a promising candidate for incorporation into health-promoting foods and nutraceuticals. These results establish DSM as a valuable source of high-value phenolic compounds.
The second experimental chapter focuses on the extraction and characterisation of lignin from DSM and its conversion into lignin nanoparticles (LNPs). The LNPs were effective, as natural stabilisers, to stabilise Pickering emulsions for 90 days. These emulsions were able to load 87.9% curcumin and 72.6% of Vitamin D3. Cell line studies confirmed the non-toxic nature of the emulsions, with LnE+Cu+vD3 causing only 29.3% and 34.9% cell death in L6 and RAW 264.7 cells, respectively, at the highest concentration (50 µg/mL). These findings establish that lignin nanoparticles derived from DSM can serve as effective Pickering emulsifiers and encapsulating materials for high-value unstable compounds.
The third experimental chapter explores the application of LNP-stabilised Pickering emulsions in creating nutrient-fortified extruded snacks. LNP-stabilised emulsions containing curcumin and vitamin D3 were incorporated into the blended flour feed and then extruded. The resulting fortified snacks retained curcumin and vitamin D3 bioavailability and improved their thermal stability by 69.0% and 65.7%, respectively. Thse findings highlight the potential of LNP stabilised emulsions to protect functional compounds and create nutrient-rich snack foods, helping to address micronutrient deficiencies while contributing to the valorisation of Ayurvedic spent materials.
The fourth experimental chapter focuses on the development of active and biodegradable packaging films using lignin and cellulose nanoparticles (LNPs and NCPs) derived from DSM. The films were produced using polyvinyl alcohol (PVOH) as the matrix, incorporating NCPs and LNPs and tea tree oil (TTO, 16% w/v) as functional additives. The resulting films exhibited 2 antimicrobial, antioxidant (85% DPPH scavenging), and UV-blocking (95% transmittance reduction) properties without compromising mechanical strength. Nanocellulose provided structure-reinforcing properties, LNPs contributed antioxidant activity and UV-blocking, and tea tree oil exhibited strong antimicrobial efficacy against E. coli. These films extended the shelf life of strawberries by 14 days under chilling conditions. These findings highlight the potential of LNPs and nanocellulose, derived from DSM, in creating sustainable active packaging solutions, extending the shelf life of perishable foods while valorising Ayurvedic waste streams.
As summarised above, DSM is a valuable source of phenolic compounds, cellulose, and lignin, which can be extracted, transformed, and applied in food and other industries. This thesis demonstrates the feasibility and importance of valorising DSM and similar Ayurvedic spent materials by using these components to produce emulsions, encapsulate unstable nutrients, develop nutritionally enriched snacks, and create active, biodegradable packaging. These findings have important implications for valorising waste in the Ayurvedic industry, promoting sustainability and waste reduction. This thesis makes a significant contribution to knowledge by advancing the extraction, transformation, and application of phenolic compounds, cellulose, and lignin from DSM. It also establishes a foundation for exploring the sustainable use of other waste streams of the Ayurvedic sector. The contribution of this work is reflected in four papers (three in Q1 journals) and one manuscript currently under review, underscoring its value to the field.
