• Korean Journal of Food Science and Technology
• /
• v.30 no.1
• /
• pp.69-76
• /
• 1998

This study was investigated to determine the effect of additives and ionic strength on the functionality of extracted proteins in preblends in order to use less additive in restructured meat products. Preblends contained the combinations of sodium chloride (NaCl; 0, 4.5, 9.0%), sodium tripolyphosphate (STPP; 0, 2.5, 5.0%), and tetrasodium pyrophosphate (PP; 0, 2.44, 4.88%). The pH values increased linearly with increasing STPP and PP concentrations (p<0.01). In the equivalent ionic strengths, PP was more effective than STPP in increasing pH. Phosphate ions were more effective on total extractable protein (used 1 M NaCl buffer) than chloride ion at equivalent ionic strengths. Solubility was decreased by adding NaCl and increasing total extractable proteins. Meat sulfhydryl contents were high with increasing total extractable proteins. When protein extracts were heated at $65^{\circ}C$, 7 min, meat sulfhydryl contents decreased and surface hydrophobicity increased (p<0.01). However, all protein extracts showed no differences in SDS-PAGE pattern. In conclusion, PP is more effective than STPP in order to use less additive but there was no linear relationship between functionnal improvement and ionic strength.

• Economic and Environmental Geology
• /
• v.56 no.4
• /
• pp.421-433
• /
• 2023

The final disposal of spent nuclear fuel(SNF) from nuclear power plants takes place in a deep geological repository. The metal canister encasing the SNF is made of cast iron and copper, and is engineered to effectively isolate radioactive isotopes for a long period of time. The SNF is further shielded by a multi-barrier disposal system comprising both engineering and natural barriers. The deep disposal environment gradually changes to an anaerobic reducing environment. In this environment, sulfide is one of the most probable substances to induce corrosion of copper canister. Stress-corrosion cracking(SCC) triggered by sulfide can carry substantial implications for the integrity of the copper canister, potentially posing a significant threat to the long-term safety of the deep disposal repository. Sulfate can exist in various forms within the deep disposal environment or be introduced from the geosphere. Sulfate has the potential to be transformed into sulfide by sulfate-reducing bacteria(SRB), and this converted sulfide can contribute to the corrosion of the copper canister. Bentonite, which is considered as a potential material for buffering and backfilling, contains oxidized sulfate minerals such as gypsum(CaSO4). If there is sufficient space for microorganisms to thrive in the deep disposal environment and if electron donors such as organic carbon are adequately supplied, sulfate can be converted to sulfide through microbial activity. However, the majority of the sulfides generated in the deep disposal system or introduced from the geosphere will be intercepted by the buffer, with only a small amount reaching the metal canister. Pyrite, one of the potential sulfide minerals present in the deep disposal environment, can generate sulfates during the dissolution process, thereby contributing to the corrosion of the copper canister. However, the quantity of oxidation byproducts from pyrite is anticipated to be minimal due to its extremely low solubility. Moreover, the migration of these oxidized byproducts to the metal canister will be restricted by the low hydraulic conductivity of saturated bentonite. We have comprehensively analyzed and summarized key research cases related to the presence of sulfates, reduction processes, and the formation and behavior characteristics of sulfides and pyrite in the deep disposal environment. Our objective was to gain an understanding of the impact of sulfates and sulfides on the long-term safety of high-level radioactive waste disposal repository.