The effect of phlorotannin extracts (PTE) (from sporophyll of Undaria pinnatifida) added at different levels (0, 25, 125, 625 µmol/g protein) on the gel properties of mackerel (Scomberomorus niphonius) myofibrillar protein (MP) was studied with and without ultraviolet A (UVA) irradiation. The results showed that the gel strength and cooking yield increased in a PTE dose-dependent manner, and at the level of 625 µmol/g protein PTE, the highest gel strength of 308.43 ± 8.12 (mN·cm) and cooking yield of 76.16 ± 1.40% were obtained in the samples treated with UVA irradiation. The same samples also showed increased carbonyl content, decreased total sulfhydryl, unwinding of α-helix, and quenching of fluorescence intensity of endogenous tryptophan, all of which indicated that elevated protein oxidation in these samples led to enhanced protein cross-linking. Results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated aggregation of myosin heavy chains (MHCs) in the UVA-treated gels with PTE, also evidenced by the dense three-dimensional network structure in these samples visualized by scanning electron microscopy (SEM). Electron spin resonance (ESR) and spin trapping results indicated that free radicals were produced during the gelation process, possibly originated from UVA-treated PTE, which played a critical role of oxidizing fish MPs, and eventually led to the improvement of the textural properties of the mackerel MP gel. PRACTICAL APPLICATION: Brown algae are a family of high-yield marine algae. Phlorotannin extracts are highly active natural substances extracted from brown algae that can have many applications. Ultraviolet A (UVA) as a green and environmentally friendly physical processing method has been widely used in food processing in recent years. The method proposed in this study could be utilized to improve properties of fish protein gel made from poorly performing low-priced fishes, and provide workable guidance for industry to expand the application of brown algae in food processing to better meet consumer's demand for high-quality marine foods.

中文翻译：

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UVA 照射下使用根皮单宁提取物增强鲭鱼肌原纤维蛋白的凝胶特性


研究了不同浓度（0、25、125、625 µmol/g 蛋白质）添加的根皮单宁提取物 (PTE)（来自裙带菜孢子叶）对鲭鱼 (Scomberomorus niphonius) 肌原纤维蛋白 (MP) 凝胶特性的影响并且没有紫外线A（UVA）照射。结果表明，凝胶强度和蒸煮产率呈PTE剂量依赖性增加，在625 µmol/g蛋白质PTE水平下，最高凝胶强度为308.43 ± 8.12 (mN·cm)，蒸煮产率为76.16 ±经过UVA照射处理的样品获得了1.40%。相同的样品还显示出羰基含量增加、总巯基减少、α-螺旋解旋以及内源色氨酸荧光强度猝灭，所有这些都表明这些样品中蛋白质氧化增加导致蛋白质交联增强。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳 (SDS-PAGE) 结果表明，经 UVA 处理的凝胶中肌球蛋白重链 (MHC) 与 PTE 聚集，扫描电子显微镜观察到的这些样品中密集的三维网络结构也证明了这一点（扫描电镜）。电子自旋共振（ESR）和自旋捕获结果表明，凝胶化过程中产生了自由基，可能源自UVA处理的PTE，它在氧化鱼MPs方面发挥了关键作用，并最终导致了质构特性的改善。鲭鱼 MP 凝胶。实际应用：褐藻是高产海藻家族。叶皮单宁提取物是从褐藻中提取的高活性天然物质，具有多种用途。 紫外线A（UVA）作为一种绿色环保的物理加工方法，近年来在食品加工中得到广泛应用。本研究提出的方法可用于改善劣质低价鱼制成的鱼蛋白凝胶的性能，为行业扩大褐藻在食品加工中的应用，更好地满足消费者对高品质的需求提供可行的指导。海洋食品。