Gianfranco Panfili

Natural antioxidants in the unsaponifiable fraction of virgin olive oils from different cultivars

An investigation on carotene, a-tocopherol and squalene contents of olives from six di†erent cultivars and 15 virgin olive oils produced in Molise region in 1995 was carried out. Olives were harvested at di†erent stages of ripe- ness and oil was extracted in industrial plants by pressure or centrifugation systems. The concentration of carotenes, a-tocopherol and squalene have been correlated, both in fruit and oil samples, with the olive ripeness index. In particu- lar a signi-cant linear correlation (R 2\ 0 E95) has been found between olive ripe- ness index and olive carotene content. In order to evaluate the stability of the extracted oil, a 6 month storage test at room temperature in the dark has been carried out. In addition to the nutritional relevance of b-carotene and a- tocopherol, the compounds studied are also characterised by antioxidant activ- ities. Within the same cultivar, tocopherol and squalene stability was inversely related to the degree of ripeness. In general, storage losses ranged, probably due to di†erent antioxidant mechanisms, from 0 to 10% for carotene, from 14 to 32% for tocopherol and from 26 to 47% for squalene. 1998 SCI. (

Lipoperoxidation and Aflatoxin Biosynthesis by Aspergillus parasiticus and A. flavus

Summary: The amount of aflatoxin produced by Aspergillus flavus and Aspergillus parasiticus grown on various aged and non-aged seeds, kept at suitable conditions of temperature and moisture, is particularly related to the peroxide numbers of the seed oils. The addition of synthetic hydroperoxides to the cultures greatly increased aflatoxin production.

Production of functional probiotic, prebiotic, and synbiotic ice creams

In this work, 3 types of ice cream were produced: a probiotic ice cream produced by adding potentially probiotic microorganisms such as Lactobacillus casei and Lactobacillus rhamnosus; a prebiotic ice cream produced by adding inulin, a prebiotic substrate; and a synbiotic ice cream produced by adding probiotic microorganisms and inulin in combination. In addition to microbial counts, pH, acidity, and physical and functional properties of the ice creams were evaluated. The experimental ice creams preserved the probiotic bacteria and had counts of viable lactic acid bacteria after frozen storage that met the minimum required to achieve probiotic effects. Moreover, most of the ice creams showed good nutritional and sensory properties, with the best results obtained with Lb. casei and 2.5% inulin.

Normal and reversed-phase HPLC for more complete evaluation of tocopherols, retinols, carotenes and sterols in dairy products

SummaryWe have previously described a normal-phase HPLC method for the simultaneous determination of α, β, γ and δ tocopherol, thecis andtrans isomers of retinol, and total carotenes in different Italian cheeses and milk. In this paper we describe a reversed-phase HPLC method using solely methanol as the mobile phase for the determination of α-tocopherol, β-+γ-tocopherols, total retinols, cholesterol, β-sitosterol, campesterol and stigmasterol, and α- and β-carotene. The method developed has been applied to some new dairy products such as natural Quark, with olive, basil or banana and to processed cheese with tomato and the results have been compared with the corresponding results obtained by the normal-phase method. The conclusion is that more complete evaluation of the tocopherol, retinol, carotene and sterol content of dairy products, especially when vegetables and fruits are present, is necessary and can be obtained using both the normal- and reversed-phase HPLC methodologies.

Effect of the Biocontrol Yeast Rhodotorula glutinis Strain LS11 on Patulin Accumulation in Stored Apples.

ABSTRACT Contamination of apples (Malus domestica) and derived juices with fungicide residues and patulin produced by Penicillium expansum are major issues of food safety. Biocontrol agents represent an alternative or supplement to chemicals for disease control. Our data show that these microbes could also contribute to actively decreasing patulin accumulation in apples. Three biocontrol agents, Rhodotorula glutinis LS11, Cryptococcus laurentii LS28, and Aureobasidium pullulans LS30, were examined for their in vitro growth in the presence of patulin and for their capability to decrease mycotoxin recovery from the medium. Strain LS11 yielded the highest growth rates and the greatest decrease of toxin recoveries. Further, it caused the appearance of two major spots on thin-layer chromatography (TLC) plates, suggesting possible metabolization of the mycotoxin. In vivo, i.e., in the low percentage of LS11-pretreated apples infected by P. expansum, patulin accumulation was significantly lower than in nontreated infected fruits. Yeast cells survived and increased in infected apples and, in a model system emulating decaying apple, resulted in accelerated breakdown of patulin and the production of the same TLC spots as those detected in vitro. These data suggest that biocontrol yeast cells surviving in decaying apples could metabolize patulin and/or negatively affect its accumulation or synthesis. To our knowledge, this is the first report describing the effect of a biocontrol agent on patulin accumulation in vivo.

Rapid assay of choline in foods using microwave hydrolysis and a choline biosensor.

A fast procedure for the determination of choline in food was developed by coupling a microwave hydrolysis procedure with an O(2)/choline oxidase-based electrochemical biosensor. Time and temperature were varied to select the best conditions for the microwave hydrolysis. Results have been compared with those found by the traditional method, constituted by hydrolysis at 70 degrees C followed by enzymatic-colorimetric assay. Data obtained by the biosensor method correlated well with the enzymatic-colorimetric assay (R(2) = 0.998). Microwave versus traditional hydrolysis gave a good correlation both with the colorimetric and with biosensor procedures with a relative error below 6%. The method is sensitive and selective enough to be used for a wide variety of food items reducing remarkably the analysis time.

Influence of thermal and other manufacturing stresses on retinol isomerization in milk and dairy products

An analytical procedure, based upon HPLC, has been used to determine the degree of isomerization of retinol (vitamin A) in various dairy products. In raw milks, which are not subjected to thermal processing, there was no conversion of the predominant all-trans-isomers to cis-isomers in samples from various species. Pasteurized milks with mild heat treatment (high quality milk) had an average 13-cis: all-trans ratio of 2.6%, while pasteurized milk treated for 15 s at temperatures ranging from 72 to 76 degrees C had an average ratio of 6.4%. Milk subjected to more severe heat treatments had a higher degree of isomerization (UHT milk, 15.7%; sterilized milk, 33.5%), consistent with increased thermal conversion of the retinol isomers. In pasteurized and UHT cream, the increase in 13-cis-isomer was also a consequence of heat treatment (pasteurized cream, 3.0%; UHT cream, 14.4%). The presence of cis isomers in fermented milk suggests that fermentation processes, directly or indirectly, can induce cis-trans isomerization. In the cheeses analysed, the extent of retinol isomerization ranged from 7.6 to 35.0%. Our results confirm the importance of individual isomers in evaluating the vitamin A status of dairy products.

Constituents of nutritional relevance in fermented milk products commercialised in Italy

Fermented milk products represent an increasing share of the dairy products consumed in Italy. The nutritional value of these products is related to the milk utilised and to the eventual presence of other ingredients (milk powder, sugar, fruit puree and fruit extracts), whereas the microrganisms used can affect texture and organoleptic characteristics. In this paper constituents of nutritional relevance such as protein, fat, total carbohydrate, amino acids, minerals, vitamin A, vitamin E and cholesterol, have been evaluated in yoghurts, fermented milks (plain and with essences) and Quark cheeses (plain and with fruits). This study confirms the high nutritional quality of fermented milks and stresses the role of non-milk ingredients in modifying and, sometimes, improving the dietary contribution of these products.

Comparative study on microwave and conventional methods for protein hydrolysis in food

SummaryA rapid microwave hydrolysis procedure was developed for amino acid determination in food. The hydrolysis was performed with 6M HCl in sealed vessels using a microwave digestion system.Bovine Serum Albumin was chosen as a model protein to compare its theoric amino acid sequence with the experimental results obtained after hydrolysis by both the traditional oven heating and the microwave methods. Furthermore the selected microwave methods were carried out on different food matrices (cheese and durum wheat) and the obtained data were compared with the traditional method results.This comparative study shows that the rapid microwave hydrolysis is as accurate and precise as the traditional hydrolysis for determining amino acids in food.

Cerulenin and tetrahydrocerulenin: stimulating factors of aflatoxin biosynthesis

Cerulenin and tetrahydrocerulenin, inhibitors of fatty acid synthetase, show a remarkable effect on aflatoxin production when added to a culture medium inoculated with Aspergillus parasiticus (NRRL 2999) during the log growth phase. During this phase of stimulation of aflatoxin production, the growth of the fungus, the different fractions of lipids, and aflatoxin, both in the mycelium and in the culture medium, were analysed. The effect of di- and hexahydrocerulenin, which do not inhibit fatty acid synthetase on the aflatoxin biosynthesis, is also described. It is hypothesized that the effect shown by cerulenin and tetrahydrocerulenin on aflatoxin production can be related to their epoxide structure.