Changes in the structure and antioxidant properties of onions by high pressure treatment.
Onions have antioxidant properties and they are an important source of bioactive compounds such as phenols. The aim of this work was to study the effect of high hydrostatic pressure (HHP) (100-600 MPa/1-3 min/25 °C) on the microstructure and antioxidant properties of onions (cv. Doux) and its relationship with changes in the extractability of potential health-related compounds. Cryo scanning electron microscopy was used to study the microstructure. Vitamin C, total phenolic content and antioxidant activity (DPPH˙, ABTS˙(+), FRAP) were also analyzed. Tonoplast, plasmalemma and cell walls were affected by the HHP treatment and it favored the diffusion of the cellular content to the intercellular spaces. Vitamin C did not show significant changes, whereas the extracted phenolic content and antioxidant activity increased at pressures of 300 or 600 MPa. Therefore, it could be concluded that HHP produced changes in membrane permeability and disruption of cell walls favoring the release of phenolic compounds from tissue and, in consequence, improving their extractability.
Group of Food Microstructure and Chemistry, Department of Food Technology, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain. jovazgu@upvnet.upv.es
José Luis
JL
Vázquez-Gutiérrez
Lucía
L
Plaza
Isabel
I
Hernando
Concepción
C
Sánchez-Moreno
Amparo
A
Quiles
Begoña
B
de Ancos
M Pilar
MP
Cano
D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification; D002462:Cell Membrane / Q000737:chemistry; D002473:Cell Wall / Q000737:chemistry; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification; D005511:Food Handling / Q000295:instrumentation / Q000379:methods*; D019697:Onions / Q000737:chemistry*; D010539:Permeability; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification; D011312:Pressure
D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts