Characterization of aroma active volatile components in roasted mullet roe

Roasted fish reaction flavor by plant-based ingredients

Currently, there are no commercially available plant-based products that replicate the flavor profile of roasted fish. As the increasing demand of plant-based meat in the recent years, the exploration of plant-based meat flavors holds significant importance. This study revealed that a blend of lysine, leucine, glutamic acid, alanine, cysteine, glucose, and algae oil (rich in docosahexaenoic acid, DHA), when subjected to heating in low pH, generated the distinct flavor like roasted mackerel. The precursor, mechanism and flavor note were investigated. Key aromatic compounds such as isovaleric acid, octanoic acid, 1,5-octadien-3-one, 2,4-octadienal, 2-octenal, furaneol, 2,5-furandicarboxaldehyde, and 2-pentenylfuran were found as important contributors in the reaction flavor model. These compounds primarily derived from heat-induced lipid oxidation, lipid degradation, and Maillard reaction of these plant-based ingredients. The development of plant-based meat flavors is crucial for promoting the substantial progress of plant-based meat products.

Effects of different thermal methods and degrees on the flavor of channel catfish (Ictalurus punctatus) fillets: Fatty acids, volatile flavor and taste compounds

The effects of different thermal processing conditions on the flavor profiles of channel catfish were evaluated in terms of fatty acids, volatile flavor and taste compounds using steaming, boiling, roasting, and microwaving with different degrees. After thermal processing, 72 volatile organic compounds were detected, including 20 hydrocarbons, 5 ketones, 20 aldehydes, 7 heterocyclic compounds, 12 alcohols and others. Meanwhile, the contents of unsaturated fatty acids like oleic acid and linoleic showed a significant decline due to their heat-sensitive properties. With regard to taste compounds, thermal processing contributed to umami amino acids and free nucleotides conversion, with the initial glutamate and IMP contents of 15.87 and 164.91 mg/100 g in raw samples mainly increasing by 2.8-10.3 and 14.4-105.5 mg/100 g in processed ones. Compared to other methods, microwaving had limited effects on flavor compounds, and steaming and roasting had better performance to improve the flavor complexity of channel catfish.

Characterization of key aroma compounds in roasted chicken using SPME, SAFE, GC-O, GC-MS, AEDA, OAV, recombination-omission tests, and sensory evaluation

Aroma compounds in the roasted breasts, thighs and skins of chicken were isolated by solvent-assisted flavor evaporation (SAFE), quantitated by gas chromatography-olfactometry-mass (GC-O-MS), analyzed by aroma extract dilution analysis (AEDA), and determined by recombination-omission tests and sensory evaluation. Forty-seven aroma compounds in total, including aldehydes, ketones, furans, pyrazines, and furanones, were selected by AEDA. Twenty-five compounds were selected as pivotal odorants (Odor Activity Value, OAV ≥ 1). Twenty aroma compounds significantly were identified by recombination and omission experiments. Anethole (fennel odor) was the highest OAV (＞ 1843). Hexanal (grassy) and (E, E)-2,4-decadienal (meaty) were the most abundant aldehydes identified in roasted chicken. 1-octen-3-ol (mushroom), methanethiol (cabbage) and dimethyl trisulfide (areca, sulfur) were considered the key compounds of the breast and thighs of roasted chicken. Notably, furanone and pyrazines, 4-hydroxy-5-methyl-3(2H)-furanone (caramel, sweet and burning odor), 3-ethyl-2,5-dimethylpyrazine (nutty, toasty) and 2,3-dimethyl-5-ethylpyrazine (nutty, toasty) had the most significant effect on roasted chicken odor, especially in the skin.

Physicochemical and Volatile Flavor Properties of Fish Skin under Conventional Frying, Air Frying and Vacuum Frying

The aim of this study was to investigate the physicochemical characteristics and volatile flavor of fried tilapia skins under three frying methods. Conventional deep-fat frying usually increases the oil content of the fried fish skin and leads to lipid oxidation, which reduces the product quality. Alternative frying methods, such as air frying for 6 and 12 min under 180 °C (AF6, and AF12) and vacuum frying at 0.085 MPa for 8 and 24 min under 120 °C (VF8, and VF24) were compared to conventional frying for 2 and 8 min under 180 °C (CF2, and CF8) for tilapia skin. Physical properties of fried skin, such as the moisture content, water activity, L* values and breaking force decreased under all frying methods, while the lipid oxidation and a*, b* values increased with the increase in frying time. In general, VF offered higher hardness of product compared to AF which had a lower breaking force. Especially AF12 and CF8 had the lowest breaking force, which indicated higher crispness. For the oil quality inside the product, AF and VF reduced conjugated dienes formation and retarded oxidation compared to CF. The results of the flavor compositions of fish skin measured using gas chromatography mass spectrometry (GC/MS) with solid phase microextraction (SPME) showed that CF obtained higher unpleasant oily odor (nonanal, 2,4-decadienal, etc.), while AF presented greater grilling flavor (pyrazine derivatives). Because fish skin fried by AF only relied on hot air, Maillard reaction derived compounds, such as methylpyrazine, 2,5-dimethylpyrazine, and benzaldehyde were the leading flavors. This made the aroma profiles of AF very different from VF and CF. Among all the approaches, AF and VF developed lower oil content, mild fat oxidation and better flavor attributes, which proves their practical applications for frying tilapia fish skin.