Abstract
Limpet, Patella vulgata is an underutilised mollusc found on rocky shores in the United Kingdom and Asia. The objective was to analyse the physical-chemical and functional properties of limpet muscle. Patella vulgata contained protein (15.3%) and lipid (2.5%). The fatty acid profile comprised saturated (28.09%), monounsaturated (24.33%) and polyunsaturated fatty acids (47. 58%). Patella vulgata muscle indicated a water-soluble protein content of 3.07% ± 0.05 and salt-soluble proteins of 2.86% ± 0.17%. Protein characterization by SDS-polyacrylamide gel electrophoresis (SDS-Page) exhibited the major bands for myofibrillar proteins including myosin heavy chain, troponin and actin. The essential amino acid profile included lysine, threonine, valine, histidine, methionine, phenylalanine, leucine and isoleucine. Limpet muscle exhibited excellent rheological properties and denatured between 50 and 60 °C as determined by differential scanning calorimetry. The gel strength and nutritional value of limpet were improved when combined with tapioca starch (10:5) and with whey protein isolate (7.5:7.5) when compared to limpet alone. Limpet flesh showed favourable interactions with other nutrients in food model systems and was further tested in real products like soups and sausages. Spices as chilli, turmeric, ginger and garlic (0.01%) were used in four soup formulations as natural anti-oxidants, and all dried formulations were stored and were monitored for lipid oxidation for 12 weeks. The recipe with the combination of turmeric and chilli exhibited the best result for inhibiting peroxide value (PV) (49.1 meq/kg of lipid, P <0.05) and inhibiting thiobarbituric reactive species (TBARS) formation (166 mg TBARS/mg lipid, P <0.05) when compared with recipe control. All spices prevented the toughness of the soup powder during storage, resulting in a better texture compared to the control. Limpet sausages, gluten free and low in salt, were also developed with and without 2% turmeric and/or 2% ginger. The recipe containing ginger alone inhibited PV (3.3 meq/kg of lipid, P <0.05) versus the control (8.04 meq/kg of lipid), while the formulation with turmeric inhibited TBARS more effectively (0.016 mg TBARS/mg lipid, P <0.05) versus control (0.05 mg TBARS/mg lipid). The texture of cooked limpet sausages had a similar texture to commercial Quorn sausages with no significant difference in gel strength values (P <0.05) and was softer than chicken sausage. These project findings indicate that underutilised limpets can contribute to valuable protein and lipids in novel food products.