Antioxidant effect of an aqueous extract of alga Cystoseira stricta during the frozen storage of Atlantic Chub mackerel (Scomber colias)

7 pages, 3 tablesAn aqueous extract of alga Cystoseira stricta was included in the glazing medium employed during the frozen storage of Atlantic Chub mackerel (Scomber colias). Rancidity stability of frozen fish muscle was determined throughout a 9-month storage at ‒18 ºC. An inhibitory effect on the development of lipid oxidation (assessment of peroxides, thiobarbituric acid and fluorescence indices) was observed as a result of the alga extract presence in the glazing system; thus, a marked retention of polyunsaturated fatty acids and alpha-tocopherol contents was achieved. Furthermore, an inhibitory effect on the lipid hydrolysis development and trimethylamine formation was implied as a result of the alga extract presence. Interestingly, enhancement of rancidity stability in frozen mackerel was found stronger by increasing the concentration of the alga extract in the glazing medium. A preservative effect of aqueous alga extract is established, this effect being attributed to the presence of potential active compounds able to stabilise radicals responsible for the lipid oxidation developmentThis work was supported by the Consejo Superior de Investigaciones Científicas (CSIC, Spain; project PIE 201370E001)Peer reviewe

Chemical composition and nutritional value of different seaweeds from the west Algerian coast

15 pages, 6 tables, 2 figuresAnalysis of proximate composition, lipid fraction (fatty acids and lipid classes), macroelements, and trace elements was carried out on brown (Cystoseira stricta; Cystoseira compressa), red (Corallina elongata), and green (Enteromorpha compressa; Ulva lactuca) seaweeds collected from the west Algerian coast to assess their nutritional value. Protein, lipid, carbohydrate, and ash content (g kg−1 dry alga) was in the ranges 58.5–141.4, 6.4–27.1, 134.0–461.1, and 246.1–764.2, respectively. The lowest caloric value was obtained for C. elongata (827.6 kcal kg−1 dry alga); the remaining values being in the range 2,106–2,479 kcal kg−1 dry alga. C. elongata and C. stricta provided the highest polyunsaturated fatty acid content, while a valuable n-6/n-3 ratio of between 0.95 and 4.20 was obtained for all species. α-Tocopherol was present in all seaweeds; the highest level was obtained in U. lactuca. Macroelements K and Na were predominant in C. compressa and C. stricta; while Mg and Ca were most abundant in E. compressa and C. elongata, respectively. In all cases, a healthy Na/K value < 0.7 was observed, and a profitable ion quotient ratio was observed in all cases, except for C. elongata. Estimated daily intake of most minerals from the algae studied is lower than the corresponding recommended daily intakeThanks to Department of Biology, Institute of Exact Sciences and Natural and Life Sciences, University Centre Ahmed Zabana of Relizane (Algeria) for the financial support of the internship of Mrs. Hanane Oucif. This work was supported by the Consejo Superior de Investigaciones Científicas (CSIC, Spain; project PIE 201370E001)Peer reviewe

Effectiveness of a combined ethanol–aqueous extract of alga Cystoseira compressa for the quality enhancement of a chilled fatty fish species

9 pages, 3 tables, 2 figuresSeaweeds have attracted an increasing attention as a new source for bioactive compounds, these include preservative compounds. This study is a first attempt to employ alga Cystoseira compressa for the preservation of chilled fish. For it, a combined ethanol–aqueous extract of this alga was included in the icing system and employed as chilling medium for the storage of horse mackerel (Trachurus trachurus) for 11 days. On the basis of the microbial groups (aerobes, psychrotrophs, proteolytic, lipolytic and Enterobacteriaceae bacteria) assessed, an inhibitory effect (p < 0.05) on microbial activity in horse mackerel muscle was observed as a result of including the alga extract in the icing medium; such preservative effect was also proved by chemical determinations related to microbial activity (pH and trimethylamine values). Additionally, a significant decrease (p < 0.05) of lipid hydrolysis (free fatty acids formation) and oxidation (fluorescent compounds formation) in fish was also observed as a result of the presence of C. compressa extracts in the icing medium. The icing medium proposed in this work (i.e., the combination of ethanolic and aqueous extracts of C. compressa) may constitute a promising strategy to the application of natural algae extracts for fatty fish storage and enhance quality retention during commercialisationThanks to Department of Biology, Institute of Exact Sciences and Natural and Life Sciences, University Centre Ahmed Zabana of Relizane (Algeria) for the financial support of the internship of Mrs. Hanane Oucif. This work was supported by the Consejo Superior de Investigaciones Científicas (CSIC, Spain; Project PIE 201370E001).Peer reviewe

Antimicrobial and antioxidant effects of alga Cystoseira compressa extract during the chilled storage of horse mackerel (Trachurus trachurus)

1 poster presented at the 47th West European Fish Technologists Association Conference, Aviva Stadium, Dublin, 9th-12th October 2017N