Flavor Encapsulation in Yeasts:  Limonene Used as a Model System for Characterization of the Release Mechanism

Abstract

Empty yeast cells are used as a new delivery system for flavor encapsulation. The flavor release mechanism from yeast cells is characterized using a series of analytical techniques, and limonene is used as a model representing a hydrophobic flavor. Furthermore, the thermal stability of the capsules was assessed. The characterization of the cell wall structure gives rise to the development of an empirical model explaining water adsorption as well as the desorption singularities observed on drying. The study of the rate of flavor release as a function of temperature and water uptake in the cell wall clearly demonstrated a particular behavior of the yeast cell wall permeability. Below a water activity around 0.7, no flavor release is permitted whereas release occurs above it. Surface analysis on dry or wet cells using atomic force microscopy is discussed.

Microencapsulation of curcumin in cells of Saccharomyces cerevisiae

“…Since T m , at given water content, is strongly affected by membrane composition (Laroche & Gervais, 2003) it seems that plasmolysis modified to some degree the lipid composition and/ or organisation of the yeast plasma membrane. The phase transition of phospholipids has also been described in Normand et al (2005) where empty spray-dried plasmolysed cells of S. cerevisiae were studied and in comparison to our results a higher T m was obtained (173°C). As mentioned above, T m depends on the moisture content of the system and on the phospholipids' composition/ structure (Laroche & Gervais, 2003).…”

“…Besides, their phospholipid membranes can behave as liposomes and have been used for the encapsulation of both hydrophobic and hydrophilic molecules, like resveratrol (Shi et al, 2008), essential oils (Bishop, Nelson, & Lamb, 1998), as well as for the water-soluble chlorogenic acid (Shi et al, 2007) and enzymes (Chow & Palecet, 2004). Normand, Dardelle, Bouquerand, Nicolas, and Johnston (2005) used the hydrophobic volative compound limonene, after encapsulation in the yeast cells, as a model and studied the release mechanism as affected by temperature and water uptake. An exceptional behaviour of this delivery system was demonstrated where temperature above 260°C and water activity above 0.7 were necessary for release to occur.…”

AVALIAÇÃO DE EFEITOS FÍSICO-QUÍMICOS NA EFICIÊNCIA DA BIOENCAPSULAÇÃO DE FLAVONOIDE LIPOSSOLÚVEL EM CÉLULAS DE LEVEDURA (Saccharomyces cerevisiae) ATRAVÉS DE CHOQUE OSMÓTICO

“…Já as temperaturas mais elevadas podem ter causado maior choque osmótico e aumento do número e/ou tamanho dos poros formados na membrana celular da levedura, levando a maior entrada de água e fisetina na célula e consequentemente maior EE%. A possível degradação causada pela temperatura mais elevada pode ter sido evitada devido a estrutura protetora da célula de levedura, que tem se demonstrado capaz de suportar altas temperaturas e manter a integridade dos componentes nela inseridos (Normand et al, 2005). Considerou-se a temperatura de 16,6 °C como ideal por ter sido encontrado maior números de pontos ótimos nesta temperatura (Figura 1).…”

MICROENCAPSULATION OF Α-Tocopherol INSIDE SACCHAROMYCES CEREVISIAE YEAST CELLS

“…Najczęściej wymienia się drożdże z gatunku Saccharomyces cerevisiae (drożdże piekarskie), stanowiące tani i ogólnodostępny produkt [1,16]. Głównymi zaletami biomasy drożdżowej, w porów-naniu z materiałami tradycyjnymi, jest pełna biokompatybilność z produktem oraz nietoksyczność, pozwalająca na niemal nieograniczone stosowanie w produkcji żyw-ności.…”

“…Ze względu na pasywny, dyfuzyjny charakter, proces ten nie wymaga stosowania skomplikowanej i drogiej aparatury, co znacząco wpływa na obniżenie kosztów. Do tej pory z powodzeniem wykorzystano tę metodę do mikrokapsułkowania barwników [1], aromatów [16,26], przeciwutleniaczy [17,21,22] oraz składników preparatów farmaceutycznych [19].…”