| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.55 MB | Adobe PDF |
Advisor(s)
Abstract(s)
Lately, many functional food products have been widely released. Functional foods are foods which promote health beyond providing basic nutrition (Sanders, 1998). Probiotic bacteria are currently used in the development of functional food products (Pimentel-González, 2009; Siró et al., 2008), yet sometimes face technological challenges when incorporated in food matrices with more aggressive environments – salt, acid or oxygen concentrations. In order to be effective, the suggested concentration for probiotic bacteria is 106 CFU/g of a product (Shah, 2000). Encapsulation is an efficient technique to overcome such difficulties since microcapsules help in their protection from both the product intrinsic properties and the gastrointestinal tract conditions. Besides the challenges originated by the food matrices and the gastrointestinal tract there is also the challenge of conservation of the viable microorganisms throughout production and storage of the delivery food product which is also a reason for encapsulating probiotics (Allan-Wojtas et al., 2008) since the encapsulation technique can also help to protect the probiotics from the storage conditions of the product and thus increase its shelf-life in which the microorganisms are inside their effectiveness range. In this research work stability of calcium alginate capsules, produced by extrusion by aerodynamically assisted flow, throughout six months storage was studied. The effect of four storage temperatures (21, 4, -20 and -80 ºC) upon the viability of free and encapsulated cells of Lactobacillus acidophilus Ki was assessed. Two types of microcapsules were produced – one with calcium alginate and another where L-cysteine·HCl was utilized as a supplement to the calcium alginate matrix.