PDF(Pubmed)
Abstract：
The red macroalgae Porphyra, commonly known as Nori, is widely used as food around the world due to its high nutrient content, including the significant abundance of colored phycobiliproteins (PBPs). Among these, R-phycocyanin (R-PC) stands out for its vibrant purple color and numerous bioactive properties, making it a valuable protein for the food industry. However, R-PC\'s limited thermal stability necessitates alternative processing methods to preserve its color and bioactive properties. Our study aimed to investigate the in-situ stability of oligomeric R-PC under high pressure (HP) conditions (up to 4000 bar) using a combination of absorption, fluorescence, and small-angle X-ray scattering (SAXS) techniques. The unfolding of R-PC is a multiphase process. Initially, low pressure induces conformational changes in the R-PC oligomeric form (trimers). As pressure increases above 1600 bar, these trimers dissociate into monomers, and at pressures above 3000 bar, the subunits begin to unfold. When returned to atmospheric pressure, R-PC partially refolds, retaining 50% of its original color absorbance. In contrast, heat treatment causes irreversible and detrimental effects on R-PC color, highlighting the advantages of HP treatment in preserving both the color and bioactive properties of R-PC compared to heat treatment.
摘要：
红藻紫菜，俗称Nori,由于其高营养成分，在世界各地被广泛用作食品，包括大量的彩色藻胆蛋白（PBPs）。其中,R-藻蓝蛋白（R-PC）因其鲜艳的紫色和众多生物活性而脱颖而出，使其成为食品工业的有价值的蛋白质。然而,R-PC有限的热稳定性需要替代加工方法来保持其颜色和生物活性。我们的研究旨在研究低聚R-PC在高压（HP）条件下（高达4000bar）的原位稳定性，荧光，和小角度X射线散射（SAXS）技术。R-PC的展开是多相过程。最初，低压诱导R-PC寡聚形式(三聚体)的构象变化。当压力增加到1600巴以上时,这些三聚体解离成单体，在3000巴以上的压力下，子单元开始展开。当恢复到大气压力时，R-PC部分折叠，保留其原始颜色吸光度的50％。相比之下,热处理会对R-PC颜色产生不可逆和有害的影响，与热处理相比，强调了HP处理在保持R-PC的颜色和生物活性方面的优势。
