Exploring the influence and mechanism of different frying methods on the flavor quality of low-salt sour meat.

To obtain nutritious, healthy, and flavor-enriched sour meat products, the effects of different frying methods (microwave, air-frying, and traditional frying) on the flavor quality of low-salt sour meat were evaluated using metabolomics and other flavor analysis techniques. The pH value of the sour meat rose dramatically, while the TBARS value dropped significantly after frying. E-nose and E-tongue results showed that air-frying could reduce acidity and improve umami. The comprehensive analysis of all samples revealed the identification of 107 volatile flavor compounds, including 10 unique aroma compounds that were specifically detected in the AF group. Additionally, the air frying process notably increased the free amino acid and nucleotide concentrations in sour meat by 53.58% and 159.29%, respectively, while causing a significant reduction in both fatty acid and lactic acid content by 22.84% and 49.29%, respectively. All three frying methods altered the flavor of the samples, but air frying performed better in terms of flavor and texture.

Emulsification properties of ovalbumin-fucoidan (OVA-FUC) binary complexes.

The poor thermal stability and emulsifying properties of ovalbumin (OVA) limit its functional performance, but these limitations may be overcome by forming binary complexes. We prepared binary complexes of OVA and fucoidan (FUC) through electrostatic self-assembly and investigated the emulsifying properties of the complex by measuring the particle size, interfacial membrane thickness, zeta potential, and stability of the emulsion prepared with camellia oil and the complex. The OVA-FUC emulsions have a thicker interfacial membrane, lower mobility, higher viscosity, and better stability compared with the OVA emulsions. The emulsion prepared with 1.5 % OVA-FUC remained stable and homogeneous during storage. They tended to become unstable with freeze-thaw, but the oil encapsulated did not leak after coalescence occurred. With the addition of Ca2+, the OVA-FUC emulsion will be converted into a gel state. These findings indicate that OVA-FUC binary complexes can be used to prepare high-performance emulsions with great potential for development.

Mechanisms of cooking methods on flavor formation of Tibetan pork.

To obtain flavor-enriched Tibetan pork products, the impact of oxidation degree on the flavor of Tibetan pork with different cooking methods (microwaving, frying, boiling, and air frying) was evaluated using an E-nose, an E-tongue, GC-MS, and LC-MS. The level of oxidation was lower in M and F and higher in B and AF groups. Hexanal, pentanal, benzaldehyde, 1-octen-3-ol, and 3-hydroxy-2-butanone were identified as significant contributors to cooked samples. The volatile abundance of microwaved, fried, boiled, and air-fried pork was 1.61, 1.22, 1.47, and 1.69 times higher than raw, respectively. Leucine and threonine were detected to be the highest in the AF group, which were 1.30 and 3.60 times greater than RAW, respectively. In summary, oxidation of lipids and proteins caused by cooking treatments was the main source of flavor in cooked Tibetan pork. Air-frying treatment could greatly promote the production of flavor compounds and give unique flavor to Tibetan pork.

Physiochemical Quality, Microbial Diversity, and Volatile Components of Monascus-Fermented Hairtail Surimi.

In order to study the effects and mechanism of Monascus on the quality of hairtail surimi, high-throughput sequencing technology, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC/MS), and electronic nose techniques were used to investigate the changes in the quality, microbial diversity, and volatile flavor compounds of Monascus-fermented hairtail surimi (MFHS) during fermentation. The results showed that the total volatile basic nitrogen (TVB-N) index of hairtail surimi fermented by Monascus for 0-5 h met the requirements of the national standard. Among them, the 1 h group showed the best gel quality, which detected a total of 138 volatile substances, including 20 alcohols, 7 aldehydes, 12 olefins, 4 phenols, 12 alkanes, 8 ketones, 15 esters, 6 acids, 16 benzenes, 4 ethers, and 8 amines, as well as 26 other compounds. In addition, the dominant fungal microorganisms in the fermentation process of MFHS were identified, and a Spearman correlation analysis showed that 16 fungal microorganisms were significantly correlated with the decrease in fishy odor substances in the fermented fish and that 8 fungal microorganisms were significantly correlated with the increase in aromatic substances after fermentation. In short, Monascus fermentation can eliminate and reduce the fishy odor substances in hairtail fish, increase and improve the aromatic flavor, and improve the quality of hairtail surimi gel. These findings are helpful for revealing the mechanism of the quality formation of fermented surimi and provide guidance for the screening of starter culture in the future.

The properties and formation mechanism of ovalbumin-fucoidan complex.

The polymeric materials formed by proteins and polysaccharides through molecular interactions have attracted public attention. In this study, a novel binary complex consisting of ovalbumin (OVA) and fucoidan (FUC) was obtained by electrostatic self-assembly. The self-assembly properties and the formation mechanism of the OVA-FUC binary complex were investigated by changing the charging degree and density of complex through altering pH value and polysaccharides proportion. Structural changes during the OVA-FUC electrostatic self-assembly process were investigated by a phase diagram, ζ-potential, and particle size. The optimal conditions for preparing soluble OVA-FUC binary complex were determined by the protein retention rate and insoluble solids content. Results showed that the soluble OVA-FUC binary complex could be obtained at the pH of 3.5 to 5, and the insoluble OVA-FUC binary complex was generated at the pH of 2.5 to 3.5. The OVA-FUC binary complex (19 ± 0.29 mN/m) possessed a medium ability to reduce interfacial tension of the water-oil interface compared with OVA (15 ± 1.13 mN/m) and FUC (24 ± 0.3 mN/m), indicating that OVA-FUC binary complex has good amphiphilicity and can be applied as a potential pH-controlled emulsifier in function food systems for delivering bioactive substances.

Effects of combined ultrasonic and microwave vacuum drying on drying characteristics and physicochemical properties of Tremella fuciformis.

This study analyzes the effects of ultrasonic waves on the drying kinetics of Tremella fuciformis during microwave vacuum drying. The physicochemical properties and structural characteristics of T. fuciformis polysaccharides (TFPs) were studied by drying tremella samples using hot air drying (HAD), microwave vacuum drying, ultrasonic pretreatments with microwave vacuum drying (US + MVD), and air-borne ultrasonic pretreatments combined with microwave vacuum drying (USMVD) under acoustic energy densities of 0.14, 0.28, and 0.42 W/mL. The results showed that USMVD and US + MVD accelerated the mass transfer process of T. fuciformis. Compared with HAD treatment, TFP samples obtained by USMVD and US + MVD had a reduced molecular weight to a certain extent, and they had stronger shear thinning ability. In addition, USMVD-TFPs at 0.42 W/mL retained higher total sugar, reducing sugar, and uronic acid, and the degree of reduction in the monosaccharide component content was small.