Richard Saint‐Louis

Institut national de la recherche scientifique, Québec, Quebec, Canada

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Publications (3)5.1 Total impact

  • Jean Mamelona, Richard Saint‐Louis, Émilien Pelletier
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    ABSTRACT: Proximate composition, amino acid and fatty acid profiles, and mineral and vitamin contents of by-products from Atlantic sea cucumber (Cucumaria frondosa) and green urchin (Strongylocentrotus droebachiensis) processing plants were investigated. Results showed that sea cucumber viscera, urchin digestive tract (UDT) and non-commercial grade gonads contained 4.5–14.4% total proteins and 1.9–4.6% lipids (wet weight basis). They were rich in essential amino acids with values of about 36% of total amino acids. Samples were also rich in polyunsaturated fatty acids (44% of total fatty acids) and showed high content in EPA (∼17% of total fatty acids), but low DHA level (0.2%) was observed. In terms of vitamins content, UDT showed highest retinol and alpha-tocopherol contents when compared to other marine samples. Results showed that by-products from echinoderm processing plants contain various nutritious components with levels generally comparable even better than their edible counterparts, and efforts should be invested to valorise these biological wastes in a world context of rarefaction of nutritional marine resources.
    International Journal of Food Science & Technology 09/2010; 45(10):2119 - 2126. · 1.24 Impact Factor
  • Jean Mamelona, Richard Saint‐Louis, Émilien Pelletier
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    ABSTRACT: Protein hydrolysates were prepared from echinoderm byproducts, including viscera (SCV) of Atlantic sea cucumber (Cucumaria frondosa) and digestive tract (UDT) and non-commercial grade gonads (UGN) of green sea urchin (Strongylocentrotus droebachiensis). Enzymatic hydrolysis was performed on defatted materials using Alcalase® 2.4L (0.75% w/w) and reaction was carried out overnight (∼16 h, 55 °C, pH 8.0). Freeze-dried hydrolysates were analysed for their nutritional composition, nitrogen solubility index and antioxidant activity. Degree of hydrolysis was low, with values of 5.6%, 4.6% and 7.0% for SCV, UDT and UGN, respectively. Hydrolysates showed high protein content (∼55%), high proportion of essential amino acids (∼35% of total amino acids) and good solubility (nitrogen solubility index ≈ 68%). They contained variable concentrations of major and trace elements with a predominance of Na and K. Hydrolysates showed apparent antioxidant activities in both ORAC assay (267–421 μmol TE g−1) and inhibition of lipid oxidation test (54–57%). Antioxidant activities were thought to be associated with the presence of antioxidant peptides in hydrolysates. Our results showed that hydrolysates from Atlantic sea cucumber and green sea urchin byproducts might serve as alternative sources of dietary proteins, with good nutritional composition, high solubility and interesting protection against oxidative stress.
    International Journal of Food Science & Technology 12/2009; 45(1):147 - 154. · 1.24 Impact Factor
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    ABSTRACT: In the present study, metabolism of tributyltin (TBT) by isolated trout hepatocytes was investigated over a short exposure time. For this, the cells were exposed to TBT, and the determination of TBT and possible metabolites was performed. Cell viability and cytochrome P-450 activity were also measured. After 15 min of exposure to 1 μM TBT, 72 ± 23% of the total tin recovery was observed in the cellular fraction, and about 3 and 4% of the total amount of tin was recovered as dibutyltin (DBT) in the cells and incubation medium, respectively. The amount of DBT leveled off after 15 min, probably because of the inhibition of cytochrome P-450. Thus, TBT is metabolized by fish hepatocytes. However, as it also inhibits cytochrome P-450 activity, it has the potential to alter its own metabolism and that of other environmental pollutants.
    Environmental Toxicology and Chemistry 10/2009; 15(11):2049 - 2052. · 2.62 Impact Factor