Preparation of octenyl succinylated kappa-carrageenan; reaction optimization, characterization, and application in low-fat vegan mayonnaise

Kappa-carrageenan (KC) esterification reaction with octenyl succinic anhydride was optimized using response surface methodology, leading to the production of a food-based emulsifier. Modified kappa-carrageenan (KCOSA) with different degrees of substitution (DS) (0.023 and 0.045) was produced, and their functional and structural properties were investigated. The results from FTIR and 1HNMR verified the successful occurrence of modification. The KC-OSA emulsions with both DS values were utterly stable after 30 days of storage, while KC failed to form emulsions. The viscosity, foaming properties, surface net charge, and gel opacity increased after modification and with an increase in its extent, while emulsion particle size and polydispersity index, gel melting temperature, and gel hardness decreased. Afterward, the KC-OSA (DS = 0.023) potential use was investigated as fat and egg yolk substitute in mayonnaise, which resulted in vegan mayonnaise samples with no phase separation after a month of storage at room temperature. Particle size measurements implied that the particle size of the mayonnaise sample was decreased with an increase in KC-OSA concentration. The results from the sensory evaluation showed that KC-OSA could be successfully implemented in low-fat vegan mayonnaise. The results from this study draw a bright horizon for the use of KC-OSA in the food industry.