Gamma irradiation preserves palmitoleic acid, a bioactive omega-7 unsaturated fatty acid, in Macrolepiota procera fresh samples
Conference Paper
Overview
Overview
abstract
FCT and COMPETE/OREN/UE- strategic projects PEstOE/AGR/UI0690/2011 (CIMO} and PEst-C/EQB/LA0006/2011 (REOUIMTE), and PhD grant to A.
Fernandes (SFRH/BD/76019/2011).
Obesity is a growing problem around the world, representing a metabolic disorder that is associated
with many severe lifestyles related diseases including card iovascular disease, diabetes, hypertension,
hyperlipidemia, and hyperuricemia [1]. Omega-? palmitoleic acid is a natural component found mainly
in vegetables, nuts, and seeds. Studies have demonstrated that monounsaturated fatty acids
suppressed appetite and short-term food intake in overweight subjects (1]. In particular, palmitoleic acid
(or a diet rich in palmitoleic acid} may favorably influence glucose and lipid metabolism [2].
Wild mushrooms are excellent to be included in low caloric diets, presenting higher levels of
unsaturated fatty acids than saturated ones (3]. Nevertheless, mushrooms are perishable and have to
be processed for extended shelf-life; gamma irradiation has been applied to extend the postharvest of
fresh mushrooms, alternatively to freezing or drying [4]. In tile present work, freezing and oven-drying
were selected and applied separately and combined with gamma irradiation to Macrolepiota procera
wild samples, in order to evaluate the effects on the content and profile of fatty acids.
After collection (Bragan~a . Northeastern Portugal}, fresh (kept at 42C}, frozen (kept at -202C in a
freezer} and dried (at 30 2C in an oven} fruiting bodies were submitted to gamma irradiation, performed
in experimental equipment with four 6°Co sources, at 0.5 and 1 kGy.Fatty acids were analyzed by gaschromatography
coupled to flame ionization detection (GC-FID).
For instance, myristic acid, palmitoleic acid and araquidic acid were lower in samples submitted to
freeze conservation. Palmitoleic acid is a good example of the inte raction among processing
technologies and gamma irradiation doses; the 0.5 kGy dose minimized tile amount of palmitoleic acid
when combined with freeze treatment, but the same dose maximized the amount of palmitoleic acid in
fresh samples.Gamma irradiation was the processing technology with the highest capacity to retain the
fatty acids profile presented by fresh samples, indicating its high potential to be developed as an
alternative conservation methodology.
