Utilization of gamma irradiation for development of shelf-stable mint coriander sauce

The mint coriander sauce (MCS) prepared using fresh herbs is known to be heat-sensitive and highly perishable with a limited shelf life (less than 2 days). Therefore, in the current study, the aim was to develop a shelf-stable MCS utilizing gamma radiation without the use of thermal processing. The D₁₀ values for yeast and mold (Y&M) and total viable counts (TVC) were observed to be 1.18 and 6.70 kGy, respectively. The gamma radiation at a dose of 25 kGy successfully achieved microbial sterility in MCS. No microbial growth was observed in irradiated samples during the entire storage period of 180 days. Significant (P < 0.05) increase in content of phenolic acids was observed during storage. After storage of 180 days, the amount of caffeic acid, vanillic acid and ferulic acid increased by 1.35, 5.71 and 2.14 fold, respectively. In comparison with fresh samples, the irradiated samples after storage showed a significant (P < 0.05) increase of 0.6 and 0.9 fold in total antioxidant activity and total phenolic content, respectively. Although, irradiation did not show significant effect on volatile aroma constituents, however, during storage a significant (P < 0.05) loss in aroma compounds was noted. During color analysis, a marginal loss in greenness and an increase in browning index (BI) were observed. MCS samples subjected to radiation treatment maintained acceptable sensory quality during the entire storage period of 180 days. These results suggested that radiation treatment can be a practical proposition for preparing a shelf-stable MCS with excellent sensory quality.