Formation of Lipid-Derived Flavors in Dry-Cured Mackerel (Scomberomorus niphonius) via Simulation of Autoxidation and Lipoxygenase-Induced Fatty Acid Oxidation

Abstract

In this study, lipoxygenase (LOX) extracted from dry-cured mackerel was purified, resulting in a 4.1-fold purification factor with a specific activity of 493.60 U/min·g. LOX enzymatic properties were assessed, referring to its optimal storage time (1–2 days), temperature (30 °C), and pH value (7.0). The autoxidation and LOX-induced oxidation of palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:2n9c), linoleic acid (C18:2n6c), arachidonic acid (C20:4), EPA (C20:5), and DHA (C22:6n3) were simulated to explore the main metabolic pathways of key flavors in dry-cured mackerel. The results showed that the highest LOX activity was observed when arachidonic acid was used as a substrate. Aldehydes obtained from LOX-treated C18:1n9c and C18:2n6c oxidation, which are important precursors of flavors, were the most abundant. The key flavors in dry-cured mackerel were found in the oxidative products of C16:0, C18:0, C18:1n9c, C18:2n6c, and C20:4. Heptanaldehyde could be produced from autoxidation or LOX-induced oxidation of C18:0 and C18:1n9c, while nonal could be produced from C18:1n9c and C18:2n6c oxidation. Metabolic pathway analysis revealed that C18:1n9c, C18:2n6c, EPA, and DHA made great contributions to the overall flavor of dry-cured mackerel. This study may provide a relevant theoretical basis for the scientific control of the overall taste and flavor of dry-cured mackerel and further standardize its production.

Changes in volatile compounds and lipid oxidation in various tissues of Nile tilapia (Oreochromis niloticus) during ice storage

“…It has been reported that due to their high odor thresholds, they have less contribution to the overall odor perception (Zhou et al, 2016). Liu, Lei, et al (2023) evaluated auto-and LOX-induced oxidation of dry-cured mackerel and found that arachidonic acid was the preferred substrate for LOX, by which a higher number of hydrocarbons and aromatics such as dodecane, benzene (1,2,4 trimethyl), and toluene, which were also found in our study, was reported. However, a lower content of such products was observed in LOX-induced oxidation of other fatty acids like EPA and DHA.…”

“…A significant increase in 1-penten-3-ol and 2-penten-1-ol was recorded in gills, skin, and muscle at day 9 of the storage period (p < 0.05, Table 2). An increase of 1-penten-3-ol can be explained by sequential LOX and hydroperoxide lyases activities on EPA (Liu, Lei, et al, 2023). In addition, Bassam et al (2022) reported that 1-penten-3-ol is a product derived from linolenic acid oxidation.…”

“…So far, many studies have been conducted to determine volatile compounds corresponding to such deterioration, like in yellow croaker (Larimichthys crocea), silver carp (Hypophthalmichthys molitrix), dry-cured mackerel (Scomberomorus niphonius), European seabass (Dicentrarchus labrax), and Atlantic salmon (Salmo salar), among others (Kritikos et al, 2020;Kunyaboon et al, 2021;Liu, Lei, et al, 2023;Zhao et al, 2021). However, volatile compound changes in tilapia during ice storage have not been explored.…”