Astaxanthin stability and color change of krill during subcritical water treatment

Abstract

Pacific krill () contains high amounts of astaxanthin, a carotenoid pigment with strong antioxidative activities. In this study, the effects of subcritical water temperatures (100-180 °C) and times (0-10 min) on color changes (*, *, and*) and astaxanthin degradation in Pacific krill were investigated. In addition, an aqueous solution of pure astaxanthin and that of crude astaxanthin from Pacific krill, both at a concentration of 5 mg/L, were subjected to treatment under subcritical water conditions using a flow-type reactor to compare the degradation of free astaxanthin and astaxanthin fatty acid esters. To compare the results of the different treatment conditions on the properties of astaxanthin, the severity factor (log ) was calculated, which ranged from 0.38 to 3.52. The extractability of astaxanthin enhanced when the subcritical water treatment was carried out at log values of 2.00-2.44. In contrast, astaxanthin underwent 50% degradation at log > 2.44. The changes in the * values correlated well with the astaxanthin content in the treated krill, while the* and * values might relate to the browning components forming owing to Maillard reaction. The results show that free astaxanthin was less stable than crude astaxanthin under subcritical water treatment.

Impact of different drying processes on the lipid deterioration and color characteristics of Penaeus vannamei

“…A good correlation existed between the AST content and red color of dried shrimps as reported by Niamnuy et al . After the shrimp was heat processed, browning occurred as a result of a higher rate of the Maillard reaction . Kchaou et al .…”

“…A good correlation existed between the AST content and red color of dried shrimps as reported by Niamnuy et al 13 After the shrimp was heat processed, browning occurred as a result of a higher rate of the Maillard reaction. 37 Kchaou et al 38 also reported the effect of Maillard reaction on browning of fish. Furthermore, Cyprian et al 39 reported a relationship between the depth of sardine yellowness and the accumulation of lipid oxidation products such as hydroperoxides and aldehydes such as malondialdehydes, some of which could react with amines, amino acids and proteins to result in browning in many fatty foods during processing.…”

Thermal‐ and Photo‐Induced Isomerization of All‐E‐ and Z‐Isomer‐Rich Xanthophylls: Astaxanthin and Its Structurally‐Related Xanthophylls, Adonirubin, and Adonixanthin

“…In adonirubin and adonixanthin, five and seven Z ‐isomer peaks were observed, respectively, which were identified by absorption maxima, shape of spectrum, and relative intensities of the Z ‐peak to the absorption maximum of the isomer (% D B /D II ) (Table 1 and Figure 2; Figures S2,S4, Supporting Information). [ 32,34,36–44 ]…”

“…Adonirubin, astaxanthin, and adonixanthin isomers were analyzed by normal‐phase HPLC with a photodiode array detector (SPD‐M20A; Shimadzu, Kyoto, Japan) according to the previously described method with some modifications. [ 36–39 ] Briefly, the analysis was conducted using two Phenomenex silica gel columns connected in tandem (Luna 5 µm Silica (2), 2 × 150 mm × 4.6 mm, 100 Å) and the mobile phase consisted of hexane/ethyl acetate/acetone (70:20:10, v/v/v). The flow rate and column temperature were set at 1.2 mL min −1 and 40 °C, respectively.…”

“…The xanthophyll isomer peaks were identified according to HPLC retention times, visible spectral data (absorption maxima and shape of spectrum), and relative intensities of the Z ‐peak at around 360–370 nm to the main absorption peak of the isomer (Figure S1, Supporting Information; % D B / D II ). [ 32,34,36–44 ] Total Z ‐isomer ratio (%) and remaining ratio (%) of xanthophylls after the storage test were assessed as shown below: [ 10,22 ] …”