Antonia M. Jiménez

Antioxidant Properties of Mediterranean Spices Compared with Common Food Additives

In this study, the antioxidant properties of Mediterranean food spices (annatto, cumin, oregano, sweet and hot paprika, rosemary, and saffron) at 5% concentration and of common food additives (butylated hydroxyanisole [BHA], butylated hydroxytoluene [BHT], and propyl gallate) at 100 microg/g are compared. The ability of these compounds to inhibit lipid peroxidation was, in decreasing order, rosemary > oregano > propyl gallate > annatto > BHA > sweet paprika > cumin > hot paprika > saffron > BHT. Deoxyribose damage is partially inhibited in the presence of cumin extract that exhibits the strongest protective action. The rest of the spices also protect deoxyribose better than the BHA and BHT used in the assay. Finally, the results obtained in the assay point to the prooxidant effect of propyl gallate. Hydrogen peroxide scavenging activity is measured by using peroxidase-based assay systems. In aqueous medium, the spice extracts show lower antioxidant activity than propyl gallate, the decreasing order being cumin > oregano > annatto > rosemary > hot paprika > sweet paprika. BHA and BHT did not scavenge H2O2 Spices are able to scavenge HOCl and protect alpha1-antiproteinase. The results indicate that rosemary and oregano are more effective HOCl scavengers than the other substances analyzed, which, in decreasing order, were propyl gallate, annatto, sweet and hot paprika, saffron, and cumin. The effect of Mediterranean food spices on the oxidative stability of refined olive oil tested by the Rancimat method was compared with common food additives during storage (72 h, 2, 4, and 6 months) at room temperature. The results showed that the spice extracts analyzed have significant stabilizing effects (P < 0.05).

Antioxidant Activity of Edible Fungi (Truffles and Mushrooms): Losses during Industrial Processing

The antioxidant properties of two raw truffles (Terfezia claveryi Chatin and Picoa juniperi Vittadini) and five raw mushrooms (Lepista nuda, Lentinus edodes, Agrocybe cylindracea, Cantharellus lutescens, and Hydnum repandum) were tested by subjecting these truffles and mushrooms to different industrial processes (freezing and canning) and comparing them with common food antioxidants (alpha-tocopherol [E-307], BHA [E-320], BHT [E-321], and propyl gallate [E-310]) with regard to their ability to inhibit lipid oxidation. All of the truffles and mushrooms analyzed exhibited higher percentages of oxidation inhibition than did the food antioxidants according to assays based on lipid peroxidation (LOO*), deoxyribose (OH*), and peroxidase (H2O2). Frozen samples exhibited a small reduction in free radical scavenger activity, but the results did not show a significant difference (P < 0.05) with respect to the raw samples, while canned truffles and mushrooms lost some antioxidant activity as a consequence of industrial processing. All of the raw and frozen truffles and mushrooms except frozen Cantharellus improved the stability of oil against oxidation (100 degrees C Rancimat), while canned samples accelerated oil degradation. Antioxidant activity during 30 days of storage was measured by the linoleic acid assay, and all of the samples except canned Terfezia, Picoa, and Hydnum showed high or medium antioxidant activity. The Trolox equivalent antioxidant capacity assay was used to provide a ranking order of antioxidant activity as measured against that of Trolox (a standard solution used to evaluate equivalent antioxidant capacity). The order of raw samples with regard to antioxidant capacity was as follows (in decreasing order): Cantharellus, Agrocybe, Lentinus, Terfezia, Picoa, Lepista, and Hydnum. Losses of antioxidant activity were detected in the processed samples of these truffles and mushrooms.

Investigation of Bolivian plant extracts for their radical scavenging activity and antioxidant activity

Fifty-four different extracts of nine Bolivian plants belonging to the family Asteraceae were evaluated for their radical scavenging activity by the DPPH*, NBT/hypoxanthine superoxide, and (*)OH/luminol chemiluminescence methods, and for their antioxidant activity by the beta-carotene bleaching test. The total phenolic content was also determined by the Folin-Ciocalteu method, and the oxidative stability by the Rancimat test. Both remarkably high phenolic content and radical scavenging and antioxidant activities were found mainly in the ethyl acetate fractions among the different plant extracts. Some ethyl acetate and even some defatted crude extracts exhibited activities comparable to those of commercial extracts/compounds, thus making it possible to consider some of the studied plants as a potential source of antioxidants of natural origin.

Evaluation of the Antioxidant Properties of Mediterranean and Tropical Fruits Compared with Common Food Additives

Several Mediterranean and tropical fruits have been analyzed in order to assess their antioxidant activity compared with that of common food additives (butylated hydroxyanisole [BHA], butylated hydroxytoluene [BHT] and propyl gallate). Among Mediterranean fruits, red grape and plum were more effective (P < 0.05) scavengers of peroxyl radicals than BHA, BHT, and propyl gallate. Of the tropical fruits, banana was the most effective scavenger of peroxyl radicals. Mediterranean and tropical fruits showed very good scavenger activity against hydroxy radicals (OH*), protecting deoxyribose better than BHA and BHT. The HOCI scavenging ability of Mediterranean fruits tested was, in decreasing order, lemon > plum > apricot > white grape > melon > red grape > mandarin > watermelon > peach > medlar > apple > orange > cherry > strawberry. However, the four varieties of pear were poor scavengers (P < 0.05). Among tropical fruits, the order of efficiency as HOCI scavengers was passion fruit > lime > passiflora > kumquat > avocado > pineapple > physalis > papaya fruit > carambola > mango > banana. All Mediterranean fruits showed an effect on hydrogen peroxide except peach. Tropical fruits also had a strong effect on hydrogen peroxide except avocado, which had no effect. The effect of Mediterranean and tropical fruits on the protection factor of refined olive oil, analyzed by the Rancimat method and compared with common food additives, was clear. Watermelon conferred a significantly (P < 0.05) greater protection than the other Mediterranean fruits. Among tropical fruits, physalis had the most stabilizing effect.