加工工艺对淡水鱼脯品质的影响

为从蛋白质角度探究加盐量和腌制时间对烧烤草鱼块品质的影响，将鲜活草鱼去鳞、头、尾、内脏后切块腌制，再在200 °C下烤制15 min，分别测定不同加盐量 (5%、6%、7%)、腌制时间 (2、4、6 h)下腌制草鱼块的食盐含量、失重率和肌原纤维蛋白的理化性质 (二级结构、表面疏水性、总巯基和二硫键含量)，以及烧烤草鱼块的色度、嫩度、水分、灰分和蛋白质含量，并对腌制烧烤草鱼块进行感官评价。结果显示，随着加盐量的增加或腌制时间的延长，腌制草鱼块的食盐和二硫键含量及表面疏水性逐渐增加，总巯基含量逐渐降低，肌原纤维蛋白的二级结构从稳定 (α-螺旋和β-折叠)向不稳定 (β-转角和无规则卷曲)转化。与对照 (未腌制)相比，腌制烧烤草鱼块的L^*值、a^*值、剪切力、水分和蛋白质含量均显著降低，灰分含量显著增加，且加盐量越多，腌制时间越长，烧烤草鱼块的水分含量越低，灰分含量越高，感官评分呈先增加后降低的趋势。研究表明，加盐量和腌制时间影响了肌原纤维蛋白结构的稳定性，促进了蛋白质的变性，导致烧烤草鱼块品质的变化。当加盐量为6%、腌制时间4 h时，烧烤草鱼块的水分和蛋白质含量较高，灰分含量较低，色泽、嫩度较好，感官评分较高。

Effect of processing technology on quality of freshwater-fish surimi product

To investigate the effect of salt amount and salting time on the quality attributes of roasted fillets from Ctenopharyngodon idella, the scales, head, tail, and internal organs of fresh C. idella were removed and cut into fillets, then salted respectively using a dry salting method [salt amount (5%, 6%, 7%) for 4 h, or salting time (2, 4, 6 h) with 6% of salt] and roasted at 200 °C for 15 min. The salt content, weight loss rate, and physicochemical properties of myofibrillar protein [secondary structure, surface hydrophobicity index (H₀), and total sulfhydryl and disulfide bond contents] of the salted fillets from C. idella, as well as the shear force, color, sensory score, and moisture, ash, and protein contents of roasted fillets from C. idella were evaluated. The results showed that as salt amount increased and salting time prolonged, the contents of salt and disulfide bond and H₀ of the salted fillets from C. idella gradually increased, the total sulfhydryl content underwent an opposite trend. α-helix and β-sheet of myofibrillar protein were turned into β-turn and random coil. Compared to the control (unsalted), the L^* and a^* values, shear force, and moisture and protein contents of the roasted fillets from C. idella with salting dropped sharply, while the ash content significantly increased. Furthermore, as the salt amount increased or salting time prolonged, the moisture content increased and ash content decreased, while the sensory score firstly increased, followed by decreasing. These results suggested that salt amount added and salting time significantly affected the secondary structure of the myofibrillar protein from salted C. idella fillets, and enhanced their denaturation, leading to the changes in quality attributes of the roasted fillets from C. idella. Compared to other salting conditions, the roasted fillets from C. idella had higher moisture and protein contents and lower ash content, as well as the better color and tenderness and the higher sensory score when fillets were salted for 4 h at 6% of salt.