## 8 Bromelain, Ficin, and Papain Peels By-Products-Based Cosmetic Applications
For the maximum efficacy in the incorporation of proteolytic enzymes in cosmetic products, incorporating stabilizing agents such as sugars, polyols, complexes, and proteins can help maintain enzyme activity during formulation and storage. Such agents (i.e., trehalose, glycerol, or EDTA) or antioxidants, such as ascorbic acid, can create a protective environment around enzyme molecules in cosmetic formulations [173; 90; 114; 174]. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Enzymes**} & **Water Solubility** & **log\(K_{\text{ow}}\)* & \multirow{2}{*}{**p\(K_{\text{a}}\)***} \\  & **(mg/L, 25 \({}^{\circ}\)C) * & & \\ \hline Bromelain & 1000 & \(-\)11.6 & 6.4; 7.1 \\ Ficin & 10,000 & 2 & 8–9 \\ Papain & 10,000 & \(-\)4.5 & 8.3 \\ \hline \hline \end{tabular}
* Physicochemical parameters were collected from PubChem ([[https://pubchem.ncbi.nlm.nih.gov](https://pubchem.ncbi.nlm.nih.gov)]([https://pubchem.ncbi.nlm.nih.gov](https://pubchem.ncbi.nlm.nih.gov))) (accessed on 24 January 2025).  
\end{table} 
Table 1: Physicochemical properties of proteolytic enzymes. Comparative Analysis of Several Aspects Regarding Bromelain, Ficin, and Papain Enzyme Peel By-Products Utilized in Cosmetic Applications  
Bromelain, ficin, and papain are all highly valued for their proteolytic properties, with each enzyme offering unique benefits in skincare applications. Several factors influence their cosmetic and cosmeceutical efficacy; thus, a comparison among these cosmetic agents is essential for comprehending their role, overcoming the current limitations, and developing advanced methods to exploit their full potential [2,17]. Although they share a similarly high proteolytic activity, due to their structural similarity and same active sites, peptide bond hydrolysis patterns demonstrate that many distinct characteristics and approaches exist among these enzymes regarding their source, methods of extraction and purification, molecular structure, optimal function pH and temperature, substrate specificity, stability, biochemical profile, exfoliation efficacy, skin type suitability, methods for incorporation in cosmetic applications, potential side effects, stabilizers and inhibitors, and finally, sustainability aspects [2,17]. All of the similar and different general profiles, characteristics, properties, and cosmetic efficacies of bromelain, ficin, and papain that have been examined, cited, and thoroughly analyzed in our study are synopsized in Tables 2-4. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Aspect/Feature \({}^{\star}\)** & \multicolumn{4}{c}{**Proteolytic Enzyme**} & \multicolumn{1}{c}{**References**} \\ \hline  & \(\bullet\) & Pineapple plant (_Ananas comosus_) & & & Papaya (_Carica pupaya_) \\  & \(\bullet\) & Found in stem, fruit, leaves, core, crown, root, and peel & \(\bullet\) & Fig (_Ficus carica_ L-) latex & \(\bullet\) & Found in unripe fruit, but also peels and leaves fruit, leaves stem, bark, root, and peel & \(\bullet\) & Purple papaya latex is more abundant and has \\ Source, Origin, and General Profile & \(\bullet\) & The crown has the highest proteolytic activity & \(\bullet\) & Fig latex is more abundant & the highest proteolytic activity & [23,35,69,70, activity] & \\  & \(\bullet\) & Complex of several thiol endopeptidase, endopeptidase, phosphatases, amylases, glucoideases, glycolasesases, glycolases, glycolases, glycolases, glycolases, glycolases, glycolases, glycolases, glycolases, glycolases, glycolases, glycolases, glycolases & \(\bullet\) & \(\bullet\) & Can be produced from [23,35,69,70, activity] & [23,35,69,70, activity] & [21] \\ Source, Origin, and physical profile & \(\bullet\) & Precipitation using ammonium sulfate ethanol or acetone ATPS (often using PEG and a salt) & \(\bullet\) & Precipitation with ethanol and saturated ATPPS & \(\bullet\) & Not a complex \\  & \(\bullet\) & Ultrafiltration & \(\bullet\) & ATPS & ATPS & [43,45,47,49