8 research outputs found
Comparison of the lipid content, fatty acid profile and sterol composition in local Italian and commercial royal jelly samples
No full textRoyal jelly (RJ) is a beehive product that has gained a significant scientific and commercial interest due to its healthy properties. In the present study, lipid content, fatty acid profile and phytosterol amount were determined in eight local and four commercial pure RJ samples. A mixture of diethyl ether/isopropanol 50/1 (v/v) was chosen to extract fat matter from RJ. Lipid amounts ranged from 2.3 and 7.2 % and from 2.0 to 3.2 % of the fresh product in local and commercial RJ, respectively. Fourteen fatty acids and three phytosterols were identified. About 70 % of the total fatty acids consisted of (E)-10-hydroxy-2-decenoic and 10-hydroxydecanoic acid. No significant difference was observed between local and commercial samples in regards to the relative amount of individual fatty acids. Sterols were in the range 179-701 and 329-1,097 mg kg-1 of fat in local and commercial RJ, respectively. A significant difference (p ≤ 0.05) was observed within RJ types in regards to the 24-methylenecholesterol fraction, amounting to 77 and 67 % of identified sterols in local and commercial products, respectively. © 2014 AOCS
Estrazione dei composti fenolici di oli di oliva vergini ed effetti di ritenzione sui fenoli ossidati
No full textL'interesse relativo agli antiossidanti naturali provenienti da matrici vegetali hanno mostrato in questi ultimi anni una tendenza all’aumento. In particolare il frutto dell'oliva ed i suoi derivati rappresentano un'importante parte nella dieta Mediterranea ed è stata riconosciuta una sorgente antiossidanti fenolici naturali. Questi composti svolgono effetti chemioprotettivi sulla salute umana oltre a contribuire alle proprietà sensoriali dell'olio vergine di oliva come piccante e amaro. Inoltre, l'alta stabilità degli oli vergini di oliva è correlata sia all'alto rapporto tra acidi grassi monoinsaturi e polinsaturi ma anche alla presenza di composti fenolici che svolgono azione antiossidante. Gli estratti idrofili dell'olio vergine di oliva contengono alcuni composti fenolici come fenoli semplici, lignani e secoiridoidi.
Inoltre, per determinare il reale contenuto di fenoli dell'olio di oliva è importante disporre di un metodo analitico capace di fornire buoni recuperi in fase di estrazione. In letteratura sono riportate principalmente due tecniche per l'estrazione dei composti fenolici dall'olio vergine di oliva: estrazione su fase solida (SPE) ed estrazione liquido-liquido (LLE). Oltre ai composti fenolici, negli ultimi cinque anni, è incrementato significativamente l'interesse verso i composti fenolici ossidati in relazione alla possibilità di risalire allo stato di freschezza/invecchiamento degli oli vergini di oliva. Lo scopo di questo lavoro è quello di valutare l'influenza di due differenti metodi di estrazione (i più utilizzati) nella separazione dei composti fenolici ossidati
Retention effects of oxidized polyphenols during analytical extraction of phenolic compounds of virgin olive oil
No full textThe hydrophilic extract of virgin olive oil contains several phenolic compounds such as simple phenols, lignans, and secoiridoids that have been widely studied in recent years. Interest in the hydrophilic extract has also been extended to the fraction
of oxidized phenols that form during storage as a consequence of oxidative stress. The present investigation compares the two most commonly used extraction methods, namely liquid–liquid extraction and SPE, on fresh virgin olive oil and that kept at different temperatures in the presence of oxygen to promote the formation
of oxidative products. The selective retention of these natural and oxidized phenolic compounds in relation to the extraction method was assessed. Quantification of eight identified phenolic molecules and 11 unknown peaks was performed by HPLC-DAD/MSD
Proteins and proteolysis in pre-term and term human milk and possible implications for infant formulae.
No full textUnderstanding the differences between the protein system of human milk and bovine milk is critical in the development of infant formulae. In this study, the proteins of bovine milk and a bovine-based wheydominant infant formula were compared with those of human milk for infants born prematurely (preterm) or at full term (term). The protein distribution of infant formula differed significantly from that of either type of human milk. A proteomic comparison between pre-term and term human milk showed a reduction of levels of b-casein and as-casein and appearance of additional products, corresponding to low molecular weight hydrolysis products of the caseins, in pre-term milk. Pre-term milk samples also had higher total nitrogen concentration and plasmin activity, consistent with the proteomic data. These results suggest the operation of a physiological mechanism that may adjust enzyme and/or protein expression to modify protein digestibility, and may facilitate design of infant formulae, closer to maternal milk, particularly for premature infants
Acción y destino de los antioxidantes naturales y sintéticos durante el proceso de fritura
No full text8 pages, 1 figure.-- Review.[EN] The action of antioxidants to delay lipid oxidation in fats
and oils is well known although most of the information is
related to their effects at room temperature during storage
or at the moderate temperatures of the accelerated
tests to measure oil stability. However, oxidation at the
high temperatures of food processes like frying, is more
complex because the availability of air is unknown and
both oxidative and thermal reactions are simultaneously
involved. In this review, the main studies defining the
action of natural and synthetic antioxidants at frying
temperatures are summarized. This review has been
divided into two main parts concerning the information on
natural antioxidants, i.e. tocopherols and other phenolic
compounds present in specific oils like olive, sesame and
rice bran oils, and on synthetic antioxidants, i.e. BHA,
BHT and TBHQ.[ES] La acción de antioxidantes para retrasar la oxidación en grasas y aceites es bien conocida aunque la mayor parte de la información está relacionada con su actividad a temperatura ambiente durante el almacenamiento o a las temperaturas moderadas de los ensayos de oxidación acelerada. Sin embargo, su efectividad a la temperatura elevada de procesos como la fritura es más compleja debido a la existencia de reacciones oxidativas y térmicas que tienen lugar simultáneamente. En esta revisión, se resumen los estudios principales que definen la acción de los antioxidantes naturales y sintéticos durante el proceso de fritura. Se ha dividido en dos partes que resumen la acción y los compuestos de degradación de los antioxidantes naturales, es decir, tocoferoles y otros compuestos fenólicos presentes en aceites de oliva, sésamo y salvado de arroz, y de los principales antioxidantes sintéticos como BHA, BHT y TBHQ.This work was supported by MICINN (projects
AGL 2007-62922 and AGL 2007-63647) and Junta
de Andalucía.Peer reviewe
