Development Of Sea Lettuce (Ulva Lactuca and Ulva Fasciata) Incorporated Crackers

Abstract

Consumer demand for functional foods is increasing rapidly. Edible green seaweeds of Ulva species are underutilized in Sri Lanka despite relative abundance. This study examines the potential for producing crackers incorporated with Ulva species as a functional food. Ulva lactuca (UL) and Ulva.fasciata (UF) collected from Southern Coast of Sri Lanka were oven dried separately (40°C/12 h) until moisture content reached below 10% and milled to a coarse powder. Crackers were prepared using wheat flour, incorporating 2% and 4% of UL or UF powder separately. Crackers incorporated with no seaweed was used as a control. Dehydrated seaweed powders and prepared crackers were analyzed for total phenolic content (Folin-Ciocalteu method), total flavonoid content (Aluminum chloride method) and radical scavenging activity (DPPH method). Radical Scavenging Activity (RSA) of UL (47.05+0.78%) and UF (48.4+0.57%) powders displayed no significant difference. Total phenolic content (TPC) of UL and UF powders were 0.80+0.048 and 0.85+0.059 mg gallic acid equivalents/g dry weight respectively (p>0.05). UL and UF powders demonstrated respective total flavonoid contents (TFC) of 9.16+0.57 and 8.38+0.17 mg rutin equivalents/g dry weight (p>0.05). Sensory evaluation revealed higher sensory attributes (p<0.05) in 4% seaweed incorporated crackers compared to control and 2% seaweed incorporated crackers. Compared to control (8.46+0.51%), 4% UL crackers (10.36+0.49%) and 4% UF crackers (9.70+0.40%) had higher crude protein contents (p<0.05). No significant differences were detected in TPC and TFC of 4% and 0% seaweed incorporated crackers (p>0.05) indicating that baking temperature may have considerably destroyed TF and TP. However, RSA of 4% UL (41.09+0.41%) and 4% UF crackers (42.30+0.69%) indicated significantly higher (p<0.05) antioxidant activity compared to control revealing that these seaweeds may contain heat stable chemical constituents besides TF and TP apparently contributing to RSA levels. The study revealed that Ulva species can be incorporated in crackers as a rich source of antioxidants along with colour and flavour properties