1.Pro-oxidant/antioxidant behaviours of ascorbic acid, tocopherol, and plant extracts in n-3 highly unsaturated fatty acid rich oil-in-water emulsions.
Jayasinghe C1, Gotoh N, Wada S. Food Chem. 2013 Dec 1;141(3):3077-84. doi: 10.1016/j.foodchem.2013.05.143. Epub 2013 Jun 10.
This study investigated the oxidative stability of n-3 highly unsaturated fatty acid (n-3 HUFA) rich (35% n-3 HUFA) oil-in-water emulsions (10 wt% oil) with commercial antioxidants and natural plant extracts. Ascorbic acid, α-tocopherol, and the extracts of Indian gooseberry fruit (Emblica officinalis) (IGFE) and sweet basil leaves (Ocimum basilicum L.) (SBLE) were used for the study as antioxidants. The progress of oxidation in the systems was evaluated at 35 °C over 120 h against a control (without antioxidant) by monitoring the formation of primary (conjugated dienes) and secondary (volatile carbonyl compounds) oxidation products. Volatile carbonyl compounds were trapped as derivatives of pentafluorophenyl hydrazine and quantified by headspace solid-phase microextraction analysis. About 40 volatile carbonyls were successfully identified by this method. trans,trans-2,4-Heptadienal, trans,cis-2,4-heptadienal, 3,5-octadien-2-one, and 1-penten-3-ol were predominant.
2.Determination of volatile compounds in New Zealand Greenshell™ mussels (Perna canaliculus) during chilled storage using solid phase microextraction gas chromatography-mass spectrometry.
Tuckey NP1, Day JR, Miller MR. Food Chem. 2013 Jan 1;136(1):218-23. doi: 10.1016/j.foodchem.2012.07.118. Epub 2012 Aug 9.
Greenshell™ mussels (Perna canaliculus) were dry-stored at 6.44±0.54°C for 8 days during which time volatile organic compounds (VOCs) were monitored using SPME GC-MS. Thirty-four VOCs were identified in homogenised mussel meat and 29 in the mussel liquor (i.e. the seawater enclosed in the mantle cavity). Of the 34 VOCs identified 20 were reliably identified throughout the storage treatment and 9 were found to change in relative concentration in homogenised mussel meat. Dimethyl sulphide, 1-penten-3-ol, 1-hexen-3-ol and 1-octen-3-ol increased during storage, whereas pentanal, hexanal, heptanal, octanal and 3-undecen-2-one decreased. In the mussel liquor, dimethyl sulphide was undetectable pre-storage, becoming detectable after 2 days, and a large increase was noted after 6 days. SPME GC-MS was a useful tool for monitoring VOC profiles of Greenshell™ mussels and could aid in the development of technologies that monitor and improve product quality and consistency.
3.Influence of casein-phospholipid combinations as emulsifier on the physical and oxidative stability of fish oil-in-water emulsions.
García-Moreno PJ1, Frisenfeldt Horn A, Jacobsen C. J Agric Food Chem. 2014 Feb 5;62(5):1142-52. doi: 10.1021/jf405073x. Epub 2014 Jan 28.
The objective of this study was to investigate the influence of casein (0.3% w/w) and phospholipid (0.5% w/w) emulsifier combinations on the physical and oxidative stability of 10% fish oil-in-water emulsions at pH 7. For that purpose, three phospholipids were evaluated, namely, lecithin (LC), phosphatidylcholine (PC), and phosphatidylethanolamine (PE). The emulsion stabilized with LC showed the best physical stability having the most negative zeta potential and the lowest mean droplet size. In addition, this emulsion was also the least oxidized in terms of peroxide value and concentration of the volatile oxidation product 1-penten-3-ol. This finding is not explained by the antioxidant activity of LC because it showed similar DPPH scavenging activity and lower metal chelating activity than the other phospholipids. Therefore, these results suggested that other factors such as the combination of casein and lecithin, which could result in a favorable structure and thickness of the interfacial layer, prevented lipid oxidation in this emulsion.
4.Physical and oxidative stability of fish oil-in-water emulsions stabilized with fish protein hydrolysates.
García-Moreno PJ1, Guadix A2, Guadix EM2, Jacobsen C3. Food Chem. 2016 Jul 15;203:124-35. doi: 10.1016/j.foodchem.2016.02.073. Epub 2016 Feb 10.
The emulsifying and antioxidant properties of fish protein hydrolysates (FPH) for the physical and oxidative stabilization of 5% (by weight) fish oil-in-water emulsions were investigated. Muscle proteins from sardine (Sardina pilchardus) and small-spotted catshark (Scyliorhinus canicula) were hydrolyzed to degrees of hydrolysis (DH) of 3-4-5-6% with subtilisin. Sardine hydrolysates with low DH, 3% and 4%, presented the most effective peptides to physically stabilize emulsions with smaller droplet size. This implied more protein adsorbed at the interface to act as physical barrier against prooxidants. This fact might also be responsible for the higher oxidative stability of these emulsions, as shown by their lowest peroxide value and concentration of volatiles such as 1-penten-3-one and 1-penten-3-ol. Among the hydrolysates prepared from small-spotted catshark only the hydrolysate with DH 3% yielded a physically stable emulsion with low concentration of unsaturated aldehydes.