Brown seaweeds are rich in polysaccharides (soluble dietary fibre), the most abundant of which are laminarin, fucoidan and alginic acid. In particular, laminarin and fucoidan are reported to possess antioxidant, antitumour, antiviral, and antibacterial activities. The objective of this study was to assess the effect of dietary supplementation of porcine diets with a seaweed extract containing laminarin and fucoidan (L/F), isolated from Laminaria digitata, on the plasma antioxidant status, muscle pH, colour, lipid oxidation and microbiology of fresh M. longissimus dorsi (LD) steaks stored in modified atmosphere packs (MAP) at 4 °C. The influence of dietary L/F on iron-induced lipid oxidation in porcine liver, heart, kidney and lung tissue homogenates was also examined. Twenty four pigs (Large White x Landrace cross consisting of 12 males and 12 females) (BW ~ 14.51 kg) were randomly assigned to one of three treatments (n=8) following a completely randomised experimental design. The CON group was fed with a basal diet. The L/F-SD group was fed with the basal diet plus a spray-dried seaweed extract containing laminarin and fucoidan at an inclusion rate of 5.37 kg/tonne of feed. The L/F-WS group was fed with the basal diet plus a wet formulation of the seaweed extract containing laminarin and fucoidan at an inclusion rate of 26.3 kg/tonne of feed. Inclusion rates are based on the laminarin and fucoidan content of the spray-dried (L/F-SD) and wet (L/F-WS) seaweed extracts. Therefore both treatment groups received diets containing L, 500 mg/kg feed and F, 420 mg/kg feed.
Dietary supplementation with L/F did not increase plasma total antioxidant status. In LD steaks stored in modified atmosphere packs (80% O2:20% CO2) for up to 15 days at 4 °C, muscle pH, surface colour (CIE ‘L*’ lightness, ‘a*’ redness and ‘b*’ yellowness values) and microbiology (psychrotrophic and mesophilic counts) were unaffected by dietary L/F. In general, levels of lipid oxidation (TBARS, mg MDA (malondialdehyde)/kg pork) followed the order: C>LF-SD>L/F-WS. A statistically significant reduction in lipid oxidation (P < 0.05) was observed in LD steaks (ranged from 0.13 to 0.91 mg MDA/kg pork) from 75% of pigs (n=6) fed with L/F-WS compared to controls (ranged from 0.19 to 1.70 mg MDA/kg pork). Iron-induced lipid oxidation increased in liver (3.20±1.43 mg MDA/kg), heart (3.26±0.26 mg MDA/kg), kidney (3.06±1.01 mg MDA/kg) and lung tissue (2.99±0.93 mg MDA/kg) homogenates over the 24 h storage period and dietary L/F-WS reduced lipid oxidation to the greatest extent in liver tissue (1.46±1.36 mg MDA/kg) homogenates.
Results demonstrate potential for the incorporation of marine-derived bioactive antioxidant components into muscle foods via the animal's diet.
NC Moroney, MN O'Grady, JV O'Doherty, JP Kerry. 2012. Addition of seaweed (Laminaria digitata) extracts containing laminarin and fucoidan to porcine diets: Influence on the quality and shelf-life of fresh pork. Meat Science, 92(4): 423 - 429. http://dx.doi.org/10.1016/j.meatsci.2012.05.005