• Characterisation of Seasonal Mytilus edulis By-Products and Generation of Bioactive Hydrolysates

      Naik, Azza Silotry; Mora, Leticia; Hayes, Maria; Bord Iascaigh Mhara; European Union; 17/SRDP/002 2018-2020 (MDPI AG, 2020-10-01)
      Mussel cultivation results in tons of by-product, with 27% of the harvest considered as reject material. In this study, mussel by-products considered to be undersized (mussels with a cooked meat yield <30%), mussels with broken shells and barnacle-fouled mussels were collected from three different locations in the west, north-west and south-west of Ireland. Samples were hydrolysed using controlled temperatures and agitation, and the proteolytic enzyme Protamex® was added at an enzyme:substrate ratio of 1:50 (w:v). The hydrolysates were freeze-dried and analysed for protein content and amino acid composition, lipid content and fatty acid methyl ester (FAME) composition, ash and techno-functional and bioactive activities. The degree of hydrolysis was determined using the Adler-Nissen pH stat method and was found to be between 2.41% ± 0% and 7.55% ± 0.6%. Mussel by-products harvested between February and May 2019 had protein contents ranging from 36.76% ± 0.41% to 52.19% ± 1.78%. The protein content of mussels collected from July to October (the spawning season) ranged from 59.07% ± 1.375% to 68.31% ± 3.42%. The ratio of essential to nonessential amino acids varied from 0.68–0.96 and it was highest for a sample collected in November from the west of Ireland. All the hydrolysate samples contained omega-3 polyunsaturated fatty acids (PUFA), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are known anti-inflammatory agents. Selected hydrolysates which had angiotensin-converting enzyme I (ACE-I; EC 3.4.15.1) and dipeptidyl peptidase IV (DPP-IV; EC 3.4.14.5) inhibitory activities were filtered using 3-kDa membrane filtration and the permeate fraction was sequenced using mass spectrometry (MS). Identified peptides were >7 amino acids in length. Following BIOPEP database mining, 91% of the by-product mussel peptides identified were found to be previously identified DPP-IV and ACE-I inhibitory peptides, and this was confirmed using in vitro bioassays. The ACE-I inhibitory activity of the by-product mussel hydrolysates ranged from 22.23% ± 1.79% to 86.08% ± 1.59% and the most active hydrolysate had an ACE-I inhibitory concentration (IC50) value of 0.2944 mg/mL compared to the positive control, captopril. This work demonstrates that by-product mussel hydrolysates have potential for use as health-promoting ingredients.
    • Marine Gelatine from Rest Raw Materials

      Milovanovic, Ivan; Hayes, Maria; Bord Iascaigh Mhara; DAFM/07/2017/PDFP (Preprints 2018, 2018-10-09)
      In recent years, demand for consumption of marine foods, and especially fish, has substantially increased worldwide. The majority of collagen available is sourced from mammalian-derived products. Although fish derived gelatine is a viable alternative to mammalian sourced gelatine, there are some challenges related to the use of fish gelatine including odour, colour, gelling and film forming properties as well as consistency in gelatine amino acid composition. Chemicals used for pre-treatment, as well as extraction conditions such as temperature and time, can influence the length of polypeptide chains that result and the functional properties of the gelatine. Compared to mammalian sources, gelatines derived from fish show notable differences in physical and chemical properties, and great care should be paid to optimization of the production process in order to obtain a product with the best properties for intended applications. The focus of this review is to explore the feasibility of producing gelatine sourced from marine processing by-products using different pre-treatment and extraction strategies with the aim of improving the techno-functional properties of the final product and improving the clean-label status of gelatines. The bioactivities of gelatine hydrolysates are also discussed.
    • Marine Gelatine from Rest Raw Materials

      Milovanovic, Ivan; Hayes, Maria; Bord Iascaigh Mhara; DAFM/07/2017/PDFP (MDPI AG, 2018-11-27)
      In recent years, demand for consumption of marine foods, and especially fish, has substantially increased worldwide. The majority of collagen available is sourced from mammalian-derived products. Although fish derived gelatine is a viable alternative to mammalian sourced gelatine, there are certain limitations related to the use of fish gelatine that include odour, colour, functional properties, and consistency in its amino acid composition. Chemicals used for pre-treatment, as well as extraction conditions such as temperature and time, can influence the length of polypeptide chains that result and the functional properties of the gelatine. Compared to traditional sources, gelatines derived from fish show significant differences in chemical and physical properties, and great care should be paid to optimization of the production process in order to obtain a product with the best properties for intended applications. The focus of this review is to explore the feasibility of producing gelatine sourced from marine processing by-products using different pre-treatment and extraction strategies with the aim of improving the techno-functional properties of the final product and improving the clean-label status of gelatines. The bioactivities of gelatine hydrolysates are also discussed.