Preservative for High Antioxidant and Antimicrobial Activity and Low Toxicity

There is an urgent need for highly efficacious and minimally toxic preservatives for vegetables and fruits to ensure extended freshness and safety. Using natural polymer starch as the matrix, we produced nicotinated starch-ethylamine (NSA) based on N,N'-carbonyldiimidazole (CDI) acting as the catalyst and 2-chloroethylaminehydrochloride as the nucleophile. To strengthen the antimicrobial and antioxidant activity, NSA was reacted with three different cinnamic acids to prepare starch derivatives bearing cinnamyl (CNSA, DNSA, and ENSA). With a grafting rate of 27%, ENSA demonstrated notable antioxidant capability reaching ∼85% at 1.6 mg/mL. Also, it displayed inhibitory indices of 88.14%, 89.11%, and 77.90% against Botrytis cinerea, Phomopsis asparagi, and Glomerella cingulate, respectively, at a concentration of 1.0 mg/mL. The cytotoxicity test showed that the 293T cell survival ratio reached 101.5%. In addition, the sample was able to extend the shelf life of the cherry tomatoes by three days. This study has successfully developed a novel starch-based preservative for fruits and vegetables that not only possesses excellent antioxidant and antimicrobial properties but also effectively extends the shelf life of produce, demonstrating its broad application prospects in the field of fruit and vegetable storage and preservation.