Development And Characterization Of Semi-Refined Carrageenan Based Edible Film Incorporated With Germinated Fenugreek (Trigonella Foenum-Graecum L.) Seeds Extract
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Date
2015-05
Authors
Fezea, Abdulaal Farhan
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
The high production cost of refined κ-carrageenan (RC) limits its applications as a packaging material. Also, application of chemical preservatives with food packaging materials may result in health hazards to consumers. Therefore, this study aimed to prepare and characterize edible active films based on the inexpensive semi-refined κ-carrageenan (SRC) incorporated with fenugreek seeds (FS) extract. Edible films based on SRC plasticized with glycerol and sorbitol at different concentrations (20‒30%) were produced and characterized. The addition of plasticizers significantly improved mechanical properties of SRC films. With increasing plasticizers concentration, the seal strength of SRC films significantly increased, whilst their oil permeability significantly reduced. Films plasticized with sorbitol were more effective oxygen barriers than glycerol plasticized films. Among all plasticized films, SRC film plasticized with 30% sorbitol had highest elongation at break and lowest oil permeability, and thus was used with the FS extract to produce active films. FS extracts were prepared and characterized. The results obtained revealed that water extract obtained from germinated FS (W-GeFS) had highest phenolic (156.3 mg GAE/ g) and flavonoid (38.5 mg CE/ g) contents and exhibited strongest antioxidant activity against a DPPH free-radical with highest antibacterial activity against Bacillus subtilis, Staphylococcus aureus and Escherichia coli compared with the other extracts. Therefore, W-GeFS was incorporated into SRC to produce active films. SRC films incorporated with W-GeFS at different concentrations
(1‒25%) were produced and characterized. Tensile strength of SRC films increased (p < 0.05) after incorporating of W-GeFS. All the resulting films were heat sealable and their oil permeability reduced (p < 0.05) after incorporating of W-GeFS. Total phenolics content, antioxidant activity and antimicrobial activity of SRC films increased (p < 0.05) with increasing W-GeFS concentration. The surface morphology of SRC films was studied by scanning electron microscopy and atomic force microscopy. SRC films incorporated with 10‒20% W-GeFS were applied onto fresh chicken breast and their performance was evaluated and compared with the control SRC film. The results obtained showed that the number of total bacteria on chicken breast samples packed with SRC films containing 15 and 20% W-GeFS did not increase and remained the same throughout the storage period of 7 days. The results of the present study suggested that the inexpensive SRC could be used for the production of edible biodegradable films with improved mechanical and barrier properties. Also, SRC could be used in association with W-GeFS to produce optimized packaging films that can be applied in active food packaging systems.
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Keywords
Edible films based on SRC plasticized , with glycerol and sorbitol.