Evaluation of synergistic effect of Chlorella vulgaris and citric acid on oxidative stability of virgin olive oil

Sesame lignans modulate aroma formation in sesame oil through the Maillard reaction and lipid oxidation in model systems

The unknown effect of sesame lignans on aroma formation in sesame oil via the Maillard reaction (MR) and lipid oxidation was investigated. Sesamin, sesamolin, or sesamol was added to 3 models: lysine+glucose (MR), cold-pressed sesame oil (SO), and MR + SO, and were heated at 120 °C for 60 min. All three lignans suppressed SO oxidation while increasing DPPH scavenging ability (p < 0.05). Lignans increased depletions of lysine and glucose and MR browning (p < 0.05). Lignans reduced most aroma-active pyrazines, aldehydes, ketones, alcohols, and esters (p < 0.05). Sesamol and sesamolin increased perceptions of the preferable aromas of nutty, roasted sesame, and popcorn while reducing the undesirable green and rancid aromas (p < 0.05). Sesamol demonstrated a stronger effect on lipid oxidation, MR browning, aroma formation, and sensory perception than sesamin and sesamolin. This study suggests that sesame lignans can modulate aroma formation and sensory perception of sesame oil by interacting with the MR and lipid oxidation pathways.

The Potential of Phaeodactylum as a Natural Source of Antioxidants for Fish Oil Stabilization

Worldwide, fish oil is an important and rich source of the health-beneficial omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). It is, however, troubled by its high susceptibility towards lipid oxidation. This can be prevented by the addition of (preferably natural) antioxidants. The current research investigates the potential of Phaeodactylum carotenoids in this regard. The oxidative stability of fish oil and fish oil with Phaeodactylum addition is evaluated by analyzing both primary (PV) and secondary (volatiles) oxidation products in an accelerated storage experiment (37 °C). A first experimental set-up shows that the addition of 2.5% (w/w) Phaeodactylum biomass is not capable of inhibiting oxidation. Although carotenoids from the Phaeodactylum biomass are measured in the fish oil phase, their presence does not suffice. In a second, more elucidating experimental set-up, fish oil is mixed in different proportions with a Phaeodactylum total lipid extract, and oxidative stability is again evaluated. It was shown that the amount of carotenoids relative to the n-3 LC-PUFA content determined oxidative stability. Systems with a fucoxanthin/n-3 LC-PUFA ratio ≥ 0.101 shows extreme oxidative stability, while systems with a fucoxanthin/n-3 LC-PUFA ratio ≤ 0.0078 are extremely oxidatively unstable. This explains why the Phaeodactylum biomass addition did not induce oxidative stability.

Assessing the Potential of Algae Extracts for Extending the Shelf Life of Rainbow Trout (Oncorhynchus mykiss) Fillets

This study evaluates the potential of different algae extracts (Crassiphycus corneus, Cc; Ulva ohnoi, Uo; Arthrospira platensis, Ap; Haematococcus pluvialis, Hp) as additives for the preservation of rainbow trout fillets. The extracts were prepared with different water to ethanol ratios from the four algae species. The highest ferric reducing antioxidant power (FRAP) was observed in Uo extracted in 80% ethanol. Ap aqueous extract also had considerable FRAP activity, in agreement with a high total phenolic content. Radical scavenging activity (DPPH) was higher in Cc 80% ethanol extract, in agreement with a high total carotenoid content. In fact, when the algae aqueous extracts were assayed on the fish fillets, their antioxidant activity exceeded that of ascorbic acid (ASC). All algae extracts delayed microbial growth and lipid oxidation processes in trout fillets throughout the cold storage period compared to controls, and also improved textural parameters, these effects being more evident for Ap and Hp. With respect to the color parameters, the Hp extract prevented the a* values (redness) from decreasing throughout cold storage, a key point when it comes to colored species, not least salmonids. On the other hand, the Ap extract was not as effective as the rest of treatments in avoiding a* and b* decrease throughout the storage period, and thereby the color parameters were impaired. The results obtained, together with the natural origin and the viability for large-scale cultivation, make algae extracts interesting fish preservative agents for the food industry.