Yangfang Ye¹, Rui Yang¹, Yongjiang Lou¹, Juanjuan Chen¹, Xiaojun Yan^1,, Huiru Tang²

The laver product is processed from fresh thallus of Pyropia yezoensis by washing, cutting, roasting, and seasoning. The nutrient composition of raw materials, semi-finished products, and finished products of P. yezoensis was systematically characterized using NMR spectroscopy and multivariate data analysis. The results showed that the nutrient composition of P. yezoensis was dominated by 11 amino acids, 11 carboxylic acids, four choline metabolites, and four sugars. The seasoning unsurprisingly caused a significant elevation in the levels of sucrose, glucose, and glutamate in the finished products, up to 38.67 ± 4.91 mg/g, 4.22 ± 0.55 mg/g, and 17.60 ± 1.93 mg/g, respectively. However, other food processing procedures such as washing and roasting may be also responsible for widespread changes of nutrient composition including amino acids, carboxylic acids, choline metabolites, laminitol, floridoside, and isofloridoside from raw materials to finished products of seaweed. Typically, the levels of choline-O-sulfate and isofloridoside were respectively decreased to 5.93 ± 0.86 mg/g and 0.67 ± 0.09 mg/g after food processing. These findings offer essential information for the effects of food processing on the nutrient composition of seaweed products and demonstrate that NMR-based metabolomic strategy is of important values for understanding the effects of food processing on the quality and taste of seaweed products.

Pyropia yezoensis nutritional value, Pyropia yezoensis processing, nuclear magnetic resonance (NMR) of Pyropia yezoensis components, multivariate data analysis