Preparation of a free-solvent extract of lycopene from grapefruit and its encapsulation in alginate beads containing sugars and biopolymers

AGUIRRE CALVO, TATIANA; SANTAGAPITA, PATRICIO R.

Concordia, Entre Ríos

Conferencia; III International Conference on Food InnovaTION, FoodInnova 2014; 2014

Universidad Nacional de Entre Ríos // FoodInnova

Lycopene (ψ,ψ-carotene, C40H56) is a naturally occurring carotenoid found in certain plants and microorganisms, which acts as a light-gathering accessory for other pigments and also prevents oxidative damage due to its antioxidant capacity. In the Food Industry, it is used as an antioxidant in dietary supplements and as a colorant. However, carotenoids could be degraded by light, O2 and thermal treatments. The encapsulation of labile compounds(like lycopene) is used to preserve them, besides of giving controlled release and adequate dosage. The purpose of this work was to study the stability of a lycopene extract obtained from an unconventional-natural source as pink grapefruit through its encapsulation in alginate beads. Grapefruit (Citrus paradisi, red variety) was obtained from Jujuy, Argentina, being this country its higher producer in South America. Several matrices were assessed for lycopene extraction: juice, pulp, slices, and freeze-dried pulp and juice. After its extraction with olive oil, emulsions were prepared by Ultraturraxusing different hydrocolloids as alginate, pectin, chitosan, or commercial and natural gums, as well as sugars (trehalose and β-cyclodextrin). Then, alginate-Ca(II) beads were prepared by the dropping method.Physicochemical properties,content, stability, and release of lycopene were analyzed considering the influence of the composition. The best matrix to extract lycopene from pink grapefruit was freeze-dried pulp, showing the higher lycopene content (18±1g/gdb), besides of conserving lycopene fine spectral structure (used as an index of isomerization). Spherical beadswere obtained(circularity from 0.60 to 0.85), with sizes ranging from 2.2 to 2.7 (±0.1) mm, being both parameters dependent of the composition. Alginate beads and those beads with trehalose and vinal gum(extracted from Prosopis ruscifolia seeds) or chitosan were the ones that best preserved lycopene content, minimizing the changes in its structure.Diffusion coefficients (D) were determined by low field-NMR, showing that lower D values corresponded to higher lycopene contents in the beads. The composition affected the microstructure of alginate beads modulating lycopene release, showingfrom a rapid release of lycopene, to simply Fickian diffusion, or even lower releases modulated by polymer chains relaxations.The results of this work can contribute to the selection of excipients to formulate alginate beads containing not only lycopene, but also labile biomolecules, being a starting point for technological applications.