## 8 Bromelain, Ficin, and Papain Peels By-Products-Based Cosmetic Applications
Such an approach not only limits waste from agricultural processing, but also lessens industry's reliance on synthetic materials, aligning with a growing demand for eco-conscious products. To some extent, dietary fiber from pineapple by-products can also serve as a food additive to enhance texture and consistency as a substrate for microbial enzyme production [40; 202]. Utilizing plant-based enzymes often involves green methods of extraction that minimize the environmental impact as compared to the production of synthetic alternatives. For instance, bromelin powder with potent enzymatic activity was successfully generated by pineapple by-products via organic, solvent-free extraction, ultrafiltration, and freeze-drying [125], while pectin and furanocumarins from fig leaves and peels were easily recovered by ionic liquids and deep eutectic solvents [68]. Similarly, papain from various papaya parts was extracted using distilled water and a citric phosphate buffer, and purified in a two-step salt precipitation method [98]. Additionally, green extraction methods, like ATPS, MAE and UAE, are energy- and time-efficient techniques able to reduce the use of harmful solvents and enhance extraction yield, and have provided great results in bromelin, ficin, and papain-based experiments [49; 50; 51; 56; 81; 99; 108; 189]. However, additional relevant clinical trials are needed to demonstrate their sustainability, effectiveness, and applicability in cosmetic formulations [189]. Integrating biodegradable enzymes contributes to sustainability and environmental impact reduction in cosmetic industries. Using plant-based by-products as raw materials decreases an industry's reliance on non-biodegradable newly extracted or synthesized ones (sustainable production cycle) [41; 181]. Such enzymes serve as renewable alternatives to harsh chemical exfoliants, and are ideal for sensitive skin types [42]. Beyond their skincare advantages, they also aid in reducing environmental pollution caused by waste disposal. The shift towards using bromelin, ficin, or papain enzymes supports biodiversity by promoting the cultivation of plants that are able to offer useful by-products, like fiber-rich fruit peels capable of being converted into composts and residual biomass repurposed for animal feed or energy biogas formation [203; 204]. Additionally, utilizing such enzymes effectively aids in minimizing complications and enhancing skin health via their anti-inflammatory and wound-healing properties; thus, a growing demand for sustainable skincare solutions has emerged [41; 181]. The utilization of bromelin, ficin, and papain also offers significant economic advantages, driving innovation and product development [205]. This approach adds value to what would otherwise be discarded, making the production process more cost-effective. Moreover, the use of natural ingredients caters to consumer demand for sustainable and ethically sourced products capable of boosting a company's profitability. Technological advancements in nanocarier systems (i.e., liposomes, nanoemulsions) facilitate the effective delivery of these enzymes, further enhancing their efficacy and promoting their use in innovative cosmetic formulations. Hence, integrating natural enzymes into nanotechnology creates a more sustainable and efficacious model for the cosmetic industry. Lately, cosmetic industries have prioritized eco-conscious practices, such as using enzymes in \"green beauty\" cosmetic or cosmeceutical formulations [41; 181; 205; 206].