Environmental Sustainability Assessment of pH-Shift Technology for Recovering Proteins from Diverse Fish Solid Side Streams

Artikel i vetenskaplig tidskrift, 2025

The demand for clean-cut seafood fillets has led to an increase in fish processing side streams, which are often considered to be low-value waste despite their potential as a source of high-quality proteins. Valorizing these side streams through innovative methods could significantly enhance global food security, reduce environmental impacts, and support circular economy principles. This study evaluates the environmental sustainability of protein recovery from herring, salmon, and cod side streams using pH-shift technology, a method that uses acid or alkaline solubilization followed by isoelectric precipitation to determine its viability as a sustainable alternative to conventional enzymatic hydrolysis. Through a Life Cycle Assessment (LCA), five key environmental impact categories were analyzed: carbon footprint, acidification, freshwater eutrophication, water use, and cumulative energy demand, based on a functional unit of 1 kg of the protein ingredient (80% moisture). The results indicate that sodium hydroxide (NaOH) use is the dominant environmental impact driver across the categories, while energy sourcing also significantly affects outcomes. Compared to conventional fish protein hydrolysate (FPH) production, pH-shift technology achieves substantial reductions in carbon footprint, acidification, and water use, exceeding 95%, highlighting its potential for lower environmental impacts. The sensitivity analyses revealed that renewable energy integration could further enhance sustainability. Conducted at a pilot scale, this study provides crucial insights into optimizing fish side stream processing through pH-shift technology, marking a step toward more sustainable seafood production and reinforcing the value of renewable energy and chemical efficiency in reducing environmental impacts. Future work should address scaling up, valorizing residual fractions, and expanding comparisons with alternative technologies to enhance sustainability and circularity.