Mara Mandrioli

Coffee Silverskin: Characterization, Possible Uses, and Safety Aspects

The reuse of coffee silverskin (CS), the main waste product of the coffee-roasting industry, could be an alternative to its environmental disposal. However, CS could also contain undesirable compounds, such as ochratoxin A (OTA) and phytosterol oxidation products (POPs). A study on the composition of CS (caffeine, moisture, dietary fibers, carbohydrates, and polyphenol contents) was carried out, with emphasis on OTA and POPs for safety reasons. The lipid fraction showed significant amounts of linoleic acid and phytosterols (7.0 and 12.1% of lipid fraction). Noticeable levels of POPs (114.11 mg/100 g CS) were found, and the phytosterol oxidation rate varied from 27.6 to 48.1%. The OTA content was 18.7-34.4 μg/kg CS, which is about 3 times higher than the European Commission limits for coffee products. The results suggest that CS could be used as a source of cellulose and/or bioactive compounds; however, the contents of POPs and OTA might represent a risk for human safety if intended for human or livestock use.

Effects of Different Rearing and Feeding Systems on Lipid Oxidation and Antioxidant Capacity of Freeze-Dried Egg Yolks

Lipid oxidation and antioxidant capacity of freeze-dried egg yolks produced with two rearing systems (battery cages and free-range) and two types of feedings (conventional and organic) were studied. Nine fresh egg yolks of each crossed treatment were pooled, frozen for a month, freeze-dried, vacuum-packed, and kept at -18 degrees C until analysis. No significant differences were observed in the lipid (58.0-62.1%) and total sterol contents (33.0-35.5 g/kg of lipids) of the freeze-dried egg yolks. Free rearing and conventional feeding systems resulted in significantly higher total tocopherol, alpha-tocopherol, and lutein contents, as compared to the battery cage and the organic feed, respectively. However, no significant differences were found in lipid oxidation (peroxide value = 0.7-0.9 mequiv of O(2)/kg of fat; thiobarbituric reactive substances = 1.0-1.3 mg of malonylaldehyde/kg of sample) and cholesterol oxidation (28.8-43.5 mg of cholesterol oxidation products/kg of lipids; 0.08-0.12% oxidized cholesterol) of freeze-dried egg yolks except for 7alpha-hydroxycholesterol, which was significantly lower in samples obtained with organic feed.

Gum arabic microcapsules as protectors of the photoinduced degradation of riboflavin in whole milk

Microcapsules (MC) made with gum arabic (GA) as shell material without and with β-carotene (βc) as core material were prepared by the spray-drying technique. The effect of these MC on the photodegradation of riboflavin (Rf) in whole milk by fluorescent daylight lamp irradiation was evaluated at a storage temperature of 4°C. The additions of 1.37mg/mL of MC without βc (MC-GA) and with 0.54μg/mL of βc (MC-βc-GA) decreased the apparent first-order rate constant of Rf photodegradation by approximately 26 and 30%, respectively. A systematic kinetic and mechanistic analysis of the results indicates that the global protective effect of the MC is mainly due to the combination of quenching of the electronically excited triplet state of Rf and scavenging of the photogenerated reactive oxygen species, such as singlet molecular oxygen, superoxide radical anion and hydroxyl radical. A minor contribution to the photoprotective effect can be also associated with the inner-filter effect exerted by the MC, which partially blocks the direct excitation of Rf. These results allow us to conclude that photodegradation of Rf in milk can be considerably reduced by the addition of small amounts of MC, avoiding large losses in the nutritional value of milk.

Detection of Fumonisins in Fresh and Dehydrated Commercial Garlic

An epidemic fungal disease caused by Fusarium proliferatum, responsible for fumonisin production (FB1, FB2, and FB3), has been reported in the main garlic-producing countries in recent years. Fumonisins are a group of structurally related toxic metabolites produced by this pathogen. The aim of this work was to establish an enzyme-linked immunosorbent assay (ELISA) procedure, mostly applied to cereals, that is suitable for fumonisin detection in garlic and compare these results to those obtained by high-performance liquid chromatography (HPLC) and screening of fresh and dehydrated garlic for toxicological risk. The results show good correlation between the two analytical methods. In fresh symptomatic garlic, fumonisin levels were higher in the basal plates than those in the portions with necrotic spots. Among the 56 commercially dehydrated garlic samples screened, three were positive by ELISA test and only one was above the limit of quantitation. The same samples analyzed by HPLC showed the presence of FB1 in trace amounts that was below the limit of quantitation; FB2 and FB3 were absent. The results are reassuring, because no substantial contamination by fumonisins was found in commercial garlic.

Stability of flavoured phytosterol-enriched drinking yogurts during storage as affected by different packaging materials.

BACKGROUND The aim of this study was to investigate the influence of different packaging materials on storage stability of flavoured phytosterol-enriched drinking yogurts. White vanilla (WV) and blood orange (BO) phytosterol-enriched drinking yogurts conditioned in mono-layer and triple-layer co-extruded plastic bottles were stored at +6 ± 1 °C for 35 days (under alternating 12 h light and 12 h darkness) to simulate shelf-life conditions. Samples were collected at three different storage times and subjected to determination of total sterol content (TSC), peroxide value (PV) and thiobarbituric acid reactive substances (TBARs). RESULTS TSC was not significantly affected by packaging material or storage time and met the quantity declared on the label. PV was significantly influenced by yogurt type × packaging material × storage time interaction and TBARs by packaging material × storage time interaction. CONCLUSION Between the two packaging materials, the triple-layer plastic mini bottle with black coloured and completely opaque intermediate layer offered the best protection against lipid oxidation.

In vitro activity of Spirulina platensis water extract against different Candida species isolated from vulvo-vaginal candidiasis cases

The high incidence of vulvo-vaginal candidiasis, combined with the growing problems about azole resistance and toxicity of antifungal drugs, highlights the need for the development of new effective strategies for the treatment of this condition. In this context, natural compounds represent promising alternatives. The cyanobacterium Spirulina platensis, a blue-green alga, exhibits antimicrobial activities against several microorganisms. Nevertheless, only few data about the antifungal properties of Spirulina platensis are available and its potential toxic effects have not been largely investigated. The aim of this study was to evaluate the in vitro activity of a fully-characterized water extract of Spirulina platensis against 22 strains of Candida spp. Prior to considering its potential topical use, we both investigated whether the extract exerted target activities on guinea pig uterine smooth muscle, and the impact of Spirulina platensis on the dominant microorganisms of the vaginal microbiota (i.e., lactobacilli), in order to exclude possible adverse events. By means of a broth microdilution assay, we found that the microalga extract possesses good antifungal properties (MIC: 0.125–0.5 mg/ml), against all the Candida species with a fungicidal activity. At the concentrations active against candida, Spirulina platensis did not modify the spontaneous basic waves pattern of uterine myometrium as underlined by the absence of aberrant contractions, and did not affect the main health-promoting bacteria of the vaginal ecosystem. Finally, we evaluated the selectivity index of our extract by testing its cytotoxicity on three different cell lines and it showed values ranging between 2 and 16. Further in vivo studies are needed, in particular to evaluate the use of control-release formulations in order to maintain Spirulina platensis concentrations at anti-Candida active doses but below the toxic levels found in the present work.