M. A. Murcia

Influence of Cooking Methods on Antioxidant Activity of Vegetables

The influence of home cooking methods (boiling, microwaving, pressure-cooking, griddling, frying, and baking) on the antioxidant activity of vegetables has been evaluated in 20 vegetables, using different antioxidant activity assays (lipoperoxyl and hydroxyl radicals scavenging and TEAC). Artichoke was the only vegetable that kept its very high scavenging-lipoperoxyl radical capacity in all the cooking methods. The highest losses of LOO. scavenging capacity were observed in cauliflower after boiling and microwaving, pea after boiling, and zucchini after boiling and frying. Beetroot, green bean, and garlic kept their antioxidant activity after most cooking treatments. Swiss chard and pepper lost OH. scavenging capacity in all the processes. Celery increased its antioxidant capacity in all the cooking methods, except boiling when it lost 14%. Analysis of the ABTS radical scavenging capacity of the different vegetables showed that the highest losses occurred in garlic with all the methods, except microwaving. Among the vegetables that increased their TEAC values were green bean, celery, and carrot after all cooking methods (except green bean after boiling). These 3 types of vegetables showed a low ABTS radical scavenging capacity. According to the method of analysis chosen, griddling, microwave cooking, and baking alternately produce the lowest losses, while pressure-cooking and boiling lead to the greatest losses; frying occupies an intermediate position. In short, water is not the cooks best friend when it comes to preparing vegetables.

Simple phenolic composition, flavonoid contents and antioxidant capacities in water-methanol extracts of Tunisian common date cultivars (Phoenixdactylifera L.)

The purpose of this study was to determine and compare the phenolic acid composition, flavonoid content and antioxidant activity of fruits from common date cultivars. The simple phenolic content ranged from 15.73 (Mermella variety) to 54.66 mg/100 g fresh weight (Korkobbi variety). Korkobbi had also the highest content of total flavonoids (54.46 quercetin equivalents/100 g fresh weight). The percentage of inhibition can reach 83% in the lipoperoxyl radical of the Korkobbi variety, while it was about 95% with the Rotbi variety for OH·. The Trolox equivalent antioxidant capacity value provided a ranking in decreasing order at 6 min: Korkobbi > Bouhattam > Baht = Smiti > Bekreri = Garn ghzal > Mermilla = Kenta > Nefzaoui = Rotbi. It seems that the highest level of flavonoids in the Korkobbi variety was principally responsible for the highest antiradical efficiency of this cultivar.

Dietary exposure assessment of pregnant women to bisphenol-A from cans and microwave containers in Southern Spain

Bisphenol-A (BPA), material for polycarbonate and epoxy resin synthesis, has been detected in canned food, among other food containers. In mammal studies, BPA transferred from mother to fetus, caused abnormality of reproductive organs, and advanced female puberty. BPA from canned food and microwave containers was analyzed using high performance liquid chromatography and gas chromatography-mass spectrometry. Population was cohort of mother-son pairs established at Granada University Hospital. Frequency of food consumption (including canned food) was studied with a semi-quantitative questionnaire. The most frequently consumed products were fish and juice cans, consumed 1-3 times/week by 34.7% and 22.3% of the study population, respectively. The women made little use of polymer microwave containers, 52.8% never using them and 45.9% using them <3 times/month. Estimated mean (standard deviation) intake of BPA was 1.1(0.839) microgram/day. No relationship was found between BPA exposure and maternal socio-demographic variables or newborn characteristics. This study offers the first estimate of BPA dietary intake by pregnant women in Southern Spain. The consumption of canned foods and drinks by these women means that their exposure was lower than EFSA estimates for the European population. Nevertheless it remains of concern, given the proven undesirable effects of low-level exposure and higher susceptibility of pregnant women.

Parabens as agents for improving crocetin esters' shelf-life in aqueous saffron extracts.

The effect of parabens on the shelf-life of crocetin esters and picrocrocin in aqueous saffron solutions was studied. Degradation of saffron crocetin esters fits a first-order kinetics model, and the results indicated that the crocetin (β-d-glucosyl)-(β-d-gentiobiosyl) esters were more stable than the crocetin di-(β-d-gentiobiosyl) esters regardless of whether trans and cis isomers were considered. Under all tested conditions both parabens gave good results, especially propyl paraben that showed a greater influence on the degradation rate constant, except for cis-crocetin di-(β-d-gentiobiosyl) ester and cis-crocetin (β-d-glucosyl)-(β-d-gentiobiosyl) ester. In presence of propyl paraben (200 mg/L), the half-life periods of trans-crocetin di-(β-d-gentiobiosyl) ester improved considerably, up to four-fold. Special attention has been paid to the effect of propyl paraben on 46 saffrons with different crocetin ester contents. No differences were observed in terms of picrocrocin. By analysis of variance, it is noteworthy that there were differences between the mean content of crocetin esters for all analysed saffron, except for trans-crocetin (β-d-glucosyl)-(β-d-gentiobiosyl) ester.

Haem Biosynthesis and Antioxidant Enzymes in Circulating Cells of Acute Intermittent Porphyria Patients.

The aims of the present study were to explore the expression pattern of haem biosynthesis enzymes in circulating cells of patients affected by two types of porphyria (acute intermittent, AIP, and variegate porphyria, VP), together with the antioxidant enzyme pattern in AIP in order to identify a possible situation of oxidative stress. Sixteen and twelve patients affected by AIP and VP, respectively, were analysed with the same numbers of healthy matched controls. Erythrocytes, neutrophils and peripheral blood mononuclear cells (PBMCs) were purified from blood, and RNA and proteins were extracted for quantitative real time PCR (qRT-PCR) and Western-blot analysis, respectively. Porhobilinogen deaminase (PBGD) and protoporphyrinogen oxidase (PPOX) gene and protein expression was analysed. Antioxidant enzyme activity and gene expression were additionally determined in blood cells, together with protein carbonyl content in plasma. PBMCs isolated from AIP patients presented low mRNA levels of PBGD when compared to controls, while PBMCs isolated from VP patients presented a decrease in PPOX mRNA. PPOX protein content was higher in AIP patients and lower in VP patients, compared to healthy controls. Regarding antioxidant enzymes, PBMCs and erythrocyte superoxide dismutase (SOD) presented statistically significant higher activity in AIP patients compared to controls, while catalase activity tended to be lower in these patients. No differences were observed regarding antioxidant gene expression in white blood cells. Circulating cells in AIP and VP patients present altered expression of haem biosynthetic enzymes, which could be useful for the differential diagnosis of these two types of porphyria in certain difficult cases. AIP patients present a condition of potential oxidative stress similar to VP patients, evidenced by the post-transcriptional activation of SOD and possible catalase impairment.

Saffron as environmental biomarker of diffuse contamination

For the first time saffron has been employed as environmental bioindicator to characterize the presence of a complex polycyclic aromatic hydrocarbons (PAHs) mixture. The objective of this study was to provide quantitative information regarding PAHs contamination in saffron in order to verify the possibility to use this spice as environmental biomarker and to determine the bioaccumulation of these compounds. 27 saffron samples coming from different countries were analyzed by stir bar sorptive extraction technique in combination with gas chromatography-ion trap tandem mass spectrometry. The data show that the samples contained different levels of contaminants but some of them have higher concentrations than the maximum residue limits (MRLs) of pollutants established by the European Commission for spices. 9 out of 27 saffron samples contained benzo[a]pyrene in a range between 10.5 and 18.5 μg/kg values higher than the MRL.