Effect of Calcium Treatment Process on the Quality Characteristics of Kelp Edible Gel Particles

Abstract

Saccharina japonica, a bioactive-rich kelp in Chinese diets, remains underexploited commercially. Current markets predominantly offer low-value primary products over advanced alginate gel-based foods. Studies show that calcium treatment significantly influences the gelling properties of calcium alginate. In this study, the effects of CaCl₂ solution temperature, pH, and gelling time on kelp edible gel particle (KEGP) quality were systematically evaluated through sensory analysis, texture profile analysis, water holding capacity measurement, cooking loss assessment, freeze-thaw stability testing, low-field nuclear magnetic resonance (NMR) analysis, and scanning electron microscopy (SEM) characterization. An orthogonal experiment is also conducted to optimize the calcium treatment parameters. The results indicated that when the CaCl₂ solution temperature was below 35°C, the overall quality of the product was higher, while the temperature above this threshold led to decreased moisture stability of the product and partial disintegration of the gel structure, resulting in reduced gel strength and sensory quality. The optimal gelling time for achieving the highest overall product quality was 4 min. Gelling for longer than 4 min reduced the moisture stability, uniformity of the gel structure, and sensory quality. Only CaCl₂ solution at pH 2 and 10 caused partial disintegration of the gel structure, reducing the gel strength and water holding capacity. Orthogonal experimental optimization identified 4 min gelation in 2% CaCl₂ solution at 20°C and pH 8 as the optimal calcium treatment parameters. These results provide a scientific basis for the preparation process of KEGP and a reference for enriching the types of kelp intensive processing products currently available on the market.