Improvement of the storage stability of C-phycocyanin in beverages by high-pressure processing

This study investigates the effect of high-pressure processing (HPP) on the structure and color stability of phycocyanin, phycocyanin-whey protein, and phycocyanin-carrageenan mixtures. All samples at pH 3.0 are very stable during HPP treatment, as evidenced by the minimal color loss and minor structural changes of phycocyanin. However, at pH 5.0 and 7.0, the materials are not stable under the same HPP treatment, losing 10-30% of the blue color intensity. Circular dichroism and intrinsic fluorescence confirmed the samples at pH 5.0 lose more secondary structure than those at pH 3.0 and pH 7.0 after HPP treatment. Electrophoresis revealed that phycocyanin-whey protein samples at pH 5.0 form large protein aggregates after HPP treatment. In addition, we also studied the stability of these HPP-treated samples under natural light exposure and found the light stability of the phycocyanin-whey protein mixture at pH 5.0 significantly improved after HPP treatment at both 450 MPa and 600 MPa. The light stability of phycocyanin-carrageenan at pH 7.0 was also improved after HPP treatment at 450 MPa. HPP treatment of the phycocyanin-whey protein and phycocyanin-carrageenan samples appears to encapsulate the blue chromophore inside the apoprotein network and decrease the attack of oxidizing radicals. This study illustrates the changes of phycocyanin under HPP treatment and yield insights to improve its storage stability under light exposure.

Automated summary

This study explores the impact of high-pressure processing (HPP) on the structure and color stability of phycocyanin, as well as its mixtures with whey protein and carrageenan. The results indicate that pH plays a significant role in the stability of the samples during HPP treatment, with pH 3.0 showing the highest stability. Furthermore, HPP treatment enhances the light stability of the samples, with improvements observed in phycocyanin-whey protein mixture at pH 5.0 and phycocyanin-carrageenan at pH 7.0.