Shelf-Life Extension of Spring Roll Wrappers using Acidification Combined with Sodium Benzoate Addition

At ambient temperature, spring roll wrappers used for roti saimai are highly perishable. Adding organic acids such as 0-0.6% citric acid or vinegar (acetic acid) was evaluated for wrapper pH and sensory acceptability. The Addition of 0.4% citric acid or 0.5% vinegar to spring roll wrappers reduced pH below 4.5 and proved acceptable for panelists. Spring roll wrappers treated with 0.4% citric acid or 0.5% vinegar with/without 0.06% sodium benzoate were packed in two bag types (polypropylene; PP and nylon-linear low density polyethylene; nylon-LLDPE) and stored at ambient and refrigerated temperatures to investigate microbial loads. Vinegar had a greater antimicrobial effect than citric acid, while microbial reduction efficacy increased through the synergistic effects of vinegar and sodium benzoate. Spring roll wrappers treated with 0.5% vinegar with/without 0.06% sodium benzoate were selected to assess changes in quality and shelf-life. Results showed no significant differences in thickness and water activity (aw) values among all conditions. Nylon-LLDPE bags maintained spring roll wrapper moisture content better than PP bags but spring roll wrappers packed in nylon-LLDPE cracked more rapidly than those packed in PP bags during storage at refrigerated temperature. Sodium benzoate also decreased spring roll wrapper springiness. Spring roll wrappers treated with 0.5% vinegar and 0.06% sodium benzoate proved an optimal when packed in PP and nylon-LLDPE bags after storage at refrigerated and ambient temperatures, with shelf-lives of 7 and 13 days respectively.