Effects of Different Processing Methods on the Quality and Physicochemical Characteristics of Laminaria japonica

Comparative evaluation of the flavor characteristics and nutritional value of different varieties of Gracilariopsis lemaneiformis by sensory flavor chemistry

Gracilariopsis lemaneiformis is an important edible marine alga, currently recognized as the second most productive seaweed in China. In this study, the flavor and nutritional components of three varieties of G. lemaneiformis-981, LuLong No. 1, and NB-18 were investigated using sensory flavor chemistry, emphasizing their potential flavor properties and health benefits. The e-tongue and e-nose profiles of G. lemaneiformis were analyzed for the first time, revealing significant differences between NB-18 and the other two varieties. Free amino acids, 5'-nucleotides, and volatile compounds (VOCs) were also evaluated. NB-18 exhibited significantly lower levels of VOCs and higher content of Glu, contributing to its superior sensory characteristics. Furthermore, it demonstrated a higher proportion of polyunsaturated fatty acids (PUFAs) and the lowest trans-fatty acid content. In conclusion, NB-18 stands out as a nutrient-rich, high-protein seaweed with excellent flavor and considerable market value, providing a strong basis for future large-scale promotion and cultivation.

The Volatile Compounds Change during Fermentation of Saccharina japonica Seedling

It is important to eliminate the fishy odor and improve the aroma quality of seafood. In this study, the Saccharina japonica (S. japonica) seedling, which is a new food material, was investigated for the effects of fermentation with Saccharomyces cerevisiae (S. cerevisiae) through sensory evaluation, GC-MS, and odor activity value (OAV) analysis. GC-MS analysis revealed the presence of 43 volatile compounds in the unfermented S. japonica seedling, with 1-octen-3-ol, hexanal, and trans-2,4-decadienal identified as the main contributors to its fishy odor. After fermentation with S. cerevisiae, 26 volatile compounds were identified in the S. japonica seedling. Notably, the major malodorous fish compounds, including 1-octen-3-ol, hexanal and trans-2,4-decadienal, were no longer present. The results indicate that fermentation with S. cerevisiae is an effective method for removing fishy malodor compounds and enhancing the volatile components with fruity, sweet, green, and floral notes in the Saccharina japonica seedling. This process facilitates the elimination of fishy malodor and enhance the fruity, sweet, green, and floral notes of S. japonica seeding and other seaweeds.

Effects of cooking methods on the physical properties and in vitro digestibility of starch isolated from Chinese yam

The objective of this study was to compare the structural and functional attributes of Chinese yam starches obtained via different domestic cooking methods. Cooking changed the crystalline type from the C type to the CB type, and disrupted the short- and long-range molecular order of Chinese yam starch. The average chain length of amylopectin in BOS (boiling starch) was the smallest at 22.78, while RWS had the longest average chain length, reaching 24.24. These alterations in molecular structure resulted in variations in functional properties such as solubility, swelling power (SP), pasting characteristics, and rheological properties. Among these alterations, boiling was the most effective method for increasing the water-binding capacity and SP of starch. Specifically, its water holding capacity was 2.12 times that of RWS. In vitro digestion experiments indicated that BOS has a higher digestion rate (k = 0.0272 min-1) and lower RDS (rapidly digestible starch), which may be related to its amylopectin chain length distribution. This study can guide us to utilize yam starch through suitable cooking methods, which is relevant for the processing and application of Chinese yam starch.