Unmasking the efficacy of Skipjack Tuna (<i>Katsuwonus Pelamis</i>) dark muscle hydrolyzate in lipid regulation: a promising component for functional food

To effectively utilize the by-products of skipjack tuna (<i>Katsuwonus Pelamis</i>) for the preparation of peptides with lipid-lowering activity, alkaline proteinase was selected from six commercial proteases to hydrolyze dark muscle. An L₁₆ (5⁴) orthogonal design was employed to optimize the hydrolysis conditions, resulting in the production of a high-peptide-content hydrolyzate named KPHs-AL. This hydrolyzate exhibited the ability to significantly reduce TG content. KPHs-AL also showed higher persuasive pancreatic lipase (PL) and cholesterol esterase (CEase) inhibitory potential than various molecular weight (Mw) fractions and other enzymatic hydrolyzates, with IC₅₀ values of 5.14 and 8.51 mg/mL, respectively. Furthermore, KPHs-AL exerted a combined effect of regulating lipid accumulation in FAA-induced steatosis HepG₂ cells, leading to decreased total cholesterol (TC) and total triglyceride (TG). Based on the high binding likelihood and interaction with specific binding sites predicted by Pepsite2, 38 peptide sequences were identified as potential PL and CEase inhibitors. Hence, KPHs-AL holds promise as a beneficial component of functional food and exhibits the potential for anti-obesity effects through the alleviation of lipid accumulation