Incorporation of Spirulina Extract in Pectin Edible Coating for Use as Antimicrobial Agent for Some Fruits

Our work aimed to investigate the incorporation of spirulina extract (which was extracted by different solvents) in edible pectin solution to produce eco-friendly edible coating materials. Ethanolic Spirulina extract (SE) showed the highest yield (17.5%), phenolic content (19.55 mg GAE/g), total carotenoids (5.54 mg/g) and antioxidant activity (78.26%). The dried SE showed the highest inhibition zone for all tested microbial strains at concentration of 350 and 500 mg/ml. Incorporation of dried SE in pectin coating solution at concentration of 200 mg/ml led to curb the bacterial growth and increased the inhibition rate of E. coli 0517-H7; and S. aureus. Guava and Apple slices samples coated with pectin solution containing 1% SE showed lower total bacterial count, also weight loss was reduced from 11.5% to 0.4% at Guava fruit, and apple slices from 7.8% to 2.5% during 24 days at cold storage. Infected fruits were decreased over a period of storage. Rate of firmness loss was reduced from (-13.9 to -5.05 gf/d) for Guava fruit and from (-9.1 to -1.05 gf/d) for apple slices which coated with 1% SE with pectin film solution during storage. Key words: Spirulina, pectin coating, Guava, Apple, microbial quality, Sensory attributes.