The effect of rosemary extract on the flavor characteristics and oxidative quality of dried Penaeus vannamei at different processing stages was explored employing an electronic tongue, an electronic nose, high performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC-MS). The results showed that rosemary extract significantly inhibited the carbonyl content and thiobarbituric acid reactive substances (TBARS) value of shrimp at the soaking, boiling, and drying stages (P < 0.05). Compared with the control group without the addition of rosemary extract, the shrimp with rosemary extract had a higher equivalent umami concentration (EUC) and a lower degradation rate of flavor nucleotides. The proportion of sweet amino acids in the rosemary treatment group was significantly higher, while the proportion of total bitter amino acids was significantly lower than that in the control group at the soaking, boiling, and drying stages (P < 0.05). The electronic nose results showed that the odor characteristics were similar between the groups with and without rosemary extract during the cooking stage. A total of 41 volatile flavor compounds were identified by GC-MS. Rosemary extract inhibited the generation of volatile flavor components including those responsible for the fishy odor such as trimethylamine at different processing stages, which may be related to the antioxidant activity of rosemary extract. Overall, rosemary extract shows good application prospects in improving the non-volatile flavor quality of shrimp when combined with thermal processing techniques.

The debittering effect of β-cyclodextrin, lactoferrin or flavourzyme at various concentrations on bone collagen peptide was evaluated by electronic tongue, color analysis and sensory evaluation. The debittering mechanism was elucidated by hydrophobicity, free amino acid content and Fourier transform infrared (FTIR) spectroscopy. Meanwhile, the impact of the different debittering methods on antioxidant properties of bone collagen peptide was explored in terms of total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, and 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS) cation radical scavenging capacity. β-Cyclodextrin at 4 g/100 mL, lactoferrin at 5 g/100 mL and flavourzyme at 1.5 g/100 mL greatly reduced the bitterness of bone collagen peptide, and flavourzyme at 1.5 g/100 mL reduced it to the lowest level. In addition, surface hydrophobicity of all debittered samples was lower than that of the control group (P < 0.05). After debittering with β-cyclodextrin or lactoferrin, the content of hydrophobic free amino acids was significantly decreased, but increased after debittering with flavourzyme (P < 0.05), suggesting that the principles of these debittering methods are different. Compared with the other debittering methods, flavourzyme treatment significantly enhanced the antioxidant ability of bone collagen peptide (P < 0.05). Thus, flavourzyme treatment offers a potential approach for the production of bone collagen peptide with acceptable bitterness intensity and high antioxidant activity.