Abstract: Kelp is an important marine biological resource and food raw material. At present, adult kelp is eaten by people, but there is a lack of systematic studies evaluating the quality characteristics of kelp at different growth periods. In this study, the main nutritional components, amino acid composition, mineral elements, fatty acids, flavor-free amino acids and cooking texture characteristics of juvenile and adult kelp were analyzed. The results showed that the ash, protein and crude fat contents of juvenile kelp were higher than those of adult kelp. The essential amino acid (EAA)/total amino acid (TAA) ratios of juvenile kelp and adult kelp were 0.36 and 0.34, respectively, and the EAA/nom-essential amino acid (NEAA) ratios were 0.57 and 0.53, respectively. The nutrient reference values (NRV) of potassium in juvenile kelp and adult kelp were 70.40% and 41.25%, respectively, and the NRV of iron were 54.60% and 16.00%, respectively. The contents of palmitic acid, myristic acid and elaidic acid in juvenile kelp were higher than those in adult kelp. The taste activity values (TAV) of umami amino acids in juvenile kelp and adult kelp were 3.46 and 0.64, the TAV of sweet amino acids were 0.27 and 0.80, and the TAV of bitter amino acids were 0.26 and 0.00, respectively. The hardness, viscosity, chewiness, adhesiveness, cohesiveness and resilience of blanched juvenile kelp were less than those of blanched mature kelp, while their elasticity was basically the same. The above results indicate that juvenile kelp have better protein nutritional potency, mineral element and elaidic acid contents, and taste and texture characteristics than adult kelp. This study provides useful information for the high-value utilization of kelp in the modern food industry, and offers inspiration for the development of the modern food industry and the kelp industry.

Key words: kelp; nutrients; essential amino acids; taste amino acids; mineral elements; texture