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The essential oils normally had low physicochemical stability and low solubility in water. These facts limit their industrial applications in general and in food formulations particularly. This chapter characterizes the physicochemical properties and the antioxidant and antimicrobial activities of three encapsulated essential oils -guava leaf, yarrow and black pepper essential oils -in hydroxypropyl-β-cyclodextrin (HPβCD).controlled release of desired food constituents [17]. Moreover, CDs are used in food formulations for flavor protection or flavor delivery [18]. Most natural and artificial flavors are volatile oils or liquids, and complexation with CDs provides a promising alternative to the conventional encapsulation technologies for flavor protection. CDs act as molecular encapsulants, protecting the flavor throughout many rigorous food-processing methods such as freezing, thawing and microwaving. β-CD as a molecular encapsulant allows the flavor quality and quantity to be preserved to a greater extent and longer period compared to other encapsulants and provides longevity to the food item [19]. In Japan, CDs have been approved as "modified starch" for food applications for more than two decades, serving to mask odors in fresh food and to stabilize fish oils. One or two European countries-for example, Hungary-have approved γ-CD for use in certain applications because of its low toxicity. It was proved that CDs may alter the sensory profile of a food and the flavor release depends of the CD type [20], the temperature [21] and may depend the solvent nature that is, water, water/alcohol mixtures, etc. [22]. Their beneficial effects essentially derive from the ability to form stable inclusion complexes with sensitive lipophilic nutrients and constituents of flavor and taste, making easy to prepare powdered flavor materials [23-25] and even to release such flavors during cooking [26]. Toxicological data are examined and an assessment of CDs from the standpoint of safety for human consumption is made [27]. Regulations are covered, showing a general trend toward a wider acceptance of CDs as food additives. The growing health consciousness of consumers and expanding market for functional foods and nutraceutical products are opening up to CDs a promising future in food industry [11].The complexation of CDs with sweetening agents such as aspartame stabilizes and improves the taste. It also eliminates the bitter aftertaste of other sweeteners such as stevioside, glycyrrhizin and rubusoside. CD itself is a promising new sweetener. Enhancement of flavor by CDs has been also claimed for alcoholic beverages such as whisky and beer [28]. The bitterness of citrus fruit juices is a major problem in the industry caused by the presence of limonoids (mainly limonin) and flavonoids (mainly naringin). Cross-linked CD polymers are useful to remove these bitter components by inclusion complexation [29]. CDs are also used to control bitterness in tannins, plant and fungal extracts; skim milk hydrolyses and overcooked tea and coffee [3...

Present work includes experimental studies related to the viscosimetric behaviour of microemulsions that consist of three compounds: isooctane (organic phase), water (aqueous phase) and Aerosol OT (surfactant). The effect of the microemulsion composition, based on the ω parameter value, and the effect caused by the temperature have been analysed in this work. In relation to the influence of temperature and the use of microemulsions in different processes, one important characteristic of this kind of systems (the percolation phenomenon) must be taken into account in the discussion of the experimental results.

The presence of sodium dodecylsulfate micelles was found to displace the equilibrium between crystal violet and sulfite ion in the direction of the former and lead to complete recovery of the dye. The underlying mechanism for this anomalous behaviour was elucidated and the rate of the reversal process determined.