International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai 90110, Thailand.
Key Laboratory of Health Risk Factors for Seafood of Zhejiang Province, College of Food Science and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China.
Molecules. 2023 Jul 20;28(14):5560. doi: 10.3390/molecules28145560.
Crustaceans are perishable with a short shelf-life. They are prone to deterioration after capture, particularly during handling, processing, and storage due to melanosis caused by polyphenoloxidase (PPO). Therefore, inhibitory effects of chitooligosaccharide (CHOS) in comparison with CHOS-catechin (CHOS-CAT), CHOS-epigallocatechin gallate (CHOS-EGCG), and CHOS-gallic acid (CHOS-GAL) conjugates on Pacific white shrimp cephalothorax PPO were studied. IC of CHOS-CAT (0.32 mg/mL) toward PPO was less than those of all conjugates tested ( < 0.05). CHOS-CAT exhibited the mixed-type inhibition. (0.58 mg/mL) and (0.02 mg/mL) of CHOS-CAT were lower than those of other conjugates ( < 0.05). CHOS-CAT showed static fluorescence-quenching, suggesting a change in micro-environment around the active site of PPO. Moreover, CHOS-CAT was linked with various amino acid residues, including Tyr208 or Tyr209 of proPPO via van der Waals, hydrophobic interaction, and hydrogen bonding as elucidated by the molecular docking of proPPO. Although CHOS-CAT had the highest PPO inhibitory activity, it showed a lower binding energy (-8.5 kcal/mol) than other samples, except for CHOS-EGCG (-10.2 kcal/mol). Therefore, CHOS-CAT could act as an anti-melanosis agent in shrimp and other crustaceans to prevent undesirable discoloration associated with quality losses.
甲壳类动物易腐，保质期短。它们在捕获后容易变质，尤其是在处理、加工和储存过程中，由于多酚氧化酶（PPO）引起的黑色素形成。因此，研究了壳寡糖（CHOS）与壳寡糖-儿茶素（CHOS-CAT）、壳寡糖-表没食子儿茶素没食子酸酯（CHOS-EGCG）和壳寡糖-没食子酸（CHOS-GAL）缀合物对太平洋白对虾头胸甲 PPO 的抑制作用。CHOS-CAT（0.32 mg/mL）对 PPO 的 IC 小于所有测试的缀合物（<0.05）。CHOS-CAT 表现出混合抑制。CHOS-CAT 的 Ki 值（0.58 mg/mL）和 Ki 值（0.02 mg/mL）均低于其他缀合物（<0.05）。CHOS-CAT 表现出静态荧光猝灭，表明 PPO 活性部位周围的微环境发生变化。此外，如原 PPO 的分子对接所示，CHOS-CAT 与各种氨基酸残基（包括前 PPO 中的 Tyr208 或 Tyr209）通过范德华力、疏水相互作用和氢键相连。虽然 CHOS-CAT 对 PPO 的抑制活性最高，但它的结合能（-8.5 kcal/mol）低于其他样品，除了 CHOS-EGCG（-10.2 kcal/mol）。因此，CHOS-CAT 可以作为虾和其他甲壳类动物的抗褐变剂，防止与质量损失相关的不良变色。
