Valorization of mullet roe by‐products for the production of polyunsaturated fatty acids rich oils

Abstract

This work examines the potential valorization of mullet roe by-products for the production of mullet roe oil using mild processes. Three different extraction methods with potential of scale-up for the food industry, namely pressure (PE), supercritical fluid extraction (SFE), and solvent extraction (SE) are examined. Mild temperature conditions to prevent oil oxidation and (wherever applicable) food-grade solvents are used. The oil yield, the composition of oils in fatty acids by GC-FID, the level of oil oxidation (peroxide value (PV), p-anisidine value (AV), K 232 K 268 , TOTOX)) and the antioxidant activity (DPPH, ABTS) are determined. SE provided the highest oil recovery, followed by SFE and PE (68%, 28% and 10% respectively). The extracted oils had a high concentration of EPA and DHA and a total of 20.7%-24.3% of identified PUFAs among the fatty acids. Oxidation was the lowest in the SFE extracted oil followed by PE, PV was <2.5 meq O2 , AV≤10 and TOTOX <15 in all examined oil samples. Further research is needed to optimize processing conditions for the increase in oil recovery.

Effect of Extraction Method on the Yield and Quality of Mullet Roe Oil

“…This is in agreement with values reported previously which varied between 18.1% and 20.3%. [6,12,13] The water content of the roe was 46.4% ± 0.2% (w.b. ).…”

“…Previous attempts with a hydraulic press instead of the expeller press provided a recovery of only 10%. [6] The oil of the two stages of the EP-SE…”

“…[2][3][4] Regarding lipid classes and fatty acid composition, fish roe oil is especially rich in 𝜔-3 PUFA and PUFA comprises in the range of 25-47% of lipids. [4][5][6] The significance of 𝜔-3 PUFA intake has long been recognized in human nutrition and play a protective role in cancer prevention and treatment, in the reduction of the occurrence of coronary heart disease and in autoimmune and inflammatory disorders. [7,8] Furthermore, fish roe oil contains a high percentage of unsaponifiable matter, polar lipids, and phospholipids and presents antioxidant properties.…”

“…[7,8] Furthermore, fish roe oil contains a high percentage of unsaponifiable matter, polar lipids, and phospholipids and presents antioxidant properties. [3,5,6] The roe of striped mullet (Mugil cephalus) is used for the production of traditional unique foodstuffs such as karasumi in Japan, botargo in Italy, and avgotaracho in Greece which is usually eaten as a garnish or a spread. [9,10] In particular, avgotaracho, is the Greek name of the final product deriving from a number of treatments including washing, salting, drying and covering with melted beeswax of the whole mullet roe.…”

“…[9][10][11][12][13] Nearly 70% of the oil consists of wax esters [9,[12][13][14][15] and the mullet roe oil contains a significant amount of PUFA (34 -47%) and 𝜔-3 PUFA (26.2 -36%). [6,9,12,13,16,17] In terms of nutrition, the lipid fraction of mullet roe was found to reduced viability in colon adenocarcinoma cells (cancer Caco-2 cells) [18] and to a significant modification of the fatty acid profile in cancer colon cells with a selective increase in 𝜔-3 PUFA levels [19] as well as to inhibition in vitro cancer cell growth. [20] Lipid extraction from fish products and by-products has been extensively studied and various methods have been applied.…”