Cellulase-Derived Fully Deacetylated Chitooligosaccharides from Marine Shell Waste for Green Food Preservation

Abstract This study prepared wholly deacetylated, low-molecular-weight chitooligosaccharides (COS) through cellulase disintegration of chitosan sourced from shrimp and crab to produce (SCO) and CCO, respectively. FTIR analysis showed that the employed conditions (55 °C, pH 5.2 in 24 h) enabled nearly complete deacetylation, 98.8% and 100%, with average molecular weights of 1.288 and 0.467 kDa, respectively. The ESI/MS findings revealed that the resulting COS consisted of monomers and polymers of D-glucosamine (1–6 units). The COS demonstrated a progressive increase in water solubility, culminating at 88% and displayed exceptional bioactivities, particularly in their scavenging activity against DPPH at concentrations of 1–6 mg/mL. SCO produced scavenging rates equivalent to 54.72 ± 2%-60.18 ± 1%, against 59.11 ± 1%- 65.29 ± 1% in the case of CCO. The antibacterial efficacy COS (1200 µg/mL) revealed maximum inhibition zones of 26 ± 1 and 22 ± 1 mm against Bacillus cereus and Escherichia coli. The inclusion of COS in yogurt and orange juice reduced the total aerobic count by about 0.7 ± 0.1 log CFU/mL and garnered excellent sensorial acceptability ratings, exceeding 4 ± 0.0. This study is innovatively using cellulase, a cost-effective, widely available enzyme, to produce fully deacetylated, low-molecular-weight COS from marine shell waste. These ameliorated COSs offer a sustainable alternative to synthetic preservatives, particularly in yogurt and orange juice. They present a potential in green food preservation and an eco-friendly approach to transforming seafood waste into high-value bioactive compounds.