Degree of antioxidant protection: a parameter to trace the origin and quality of goat's milk and cheese.

Traceability is an essential tool in reassuring consumers and traders that food is as safe, authentic, and of good quality as expected. Today, food traceability procedures often consist of attached documents and declarations, but scientific parameters that could objectively identify a product would be preferable. Scientific efforts in this area are mostly focused on selection and validation of experimental indicators that would be useful for tracing a food product in any step of its commercial life, describing its raw materials, processing procedures, and storage conditions. In this research, milk and cheese samples from zero grazing and grazing goats were studied to identify a tracing parameter correlated to the feeding system. In particular, alpha-tocopherol and cholesterol were analyzed by HPLC on a normal phase column and were combined to calculate the degree of antioxidant protection (DAP). This parameter, expressed as the molar ratio between antioxidant compounds and an oxidation target, is useful for tracing and distinguishing products from grazing and zero-grazing animals. Degree of antioxidant protection values greater than 7.0 x 10(-3) were found in samples from grazing goats and values lower than 7.0 x 10(-3) were found in samples from zero-grazing goats, for both milk and cheese, meaning that cholesterol was highly protected against oxidative reactions when herbage was the only feed or was dominant in the goat diet. The reliability of DAP to measure the antioxidant protection of cholesterol appeared more effective when the feeding system was based on grazing than when cut herbage was utilized indoors by animals. The DAP index was able to distinguish dairy products when the grazed herbage in the goats' diet exceeded 15%.

Nutrient content of earthworms consumed by Ye'Kuana Amerindians of the Alto Orinoco of Venezuela.

For the Makiritare (Ye'Kuana) native people of the Alto Orinoco (Venezuela), earthworms (Anellida: Glossoscolecidae) are an important component of the diet. Two species in particular are widely consumed: 'kuru' (Andiorrhinus kuru n. sp.) and 'motto' (Andiorrhinus motto). We analysed eviscerated kuru body proper, and whole and smoked preparations of motto for their content of protein and amino acids, fatty acids and 20 minerals and trace elements. The samples contained large amounts of protein (64.5-72.9% of dry weight), essential amino acids, calcium and iron together with notable quantities of other important elements, indicating that these earthworms contain potentially useful quantities of many nutrients that are critical to the health of the humans who consume them.

Solid-state (13)C CP MAS NMR spectroscopy of mushrooms gives directly the ratio between proteins and polysaccharides.

The solid-state (13)C CP MAS NMR technique has the potential of monitoring the chemical composition in the solid state of an intact food sample. This property has been utilized to study mushrooms of different species (Pleurotus ostreatus, Pleurotus eryngii, Pleurotus pulmunarius, and Lentinula edodes), already characterized by chemical analyses for protein and dietary fiber components. Solid-state (13)C CP MAS NMR spectroscopy reveals a large difference in the ratio between the glucidic and the proteic resonances probably depending on the mushroom species. An accurate inspection by model compounds and suitable mixtures of proteins and saccharides gives a methodology to interpret these experimental data. A good correlation (R(2) = 0.93; R(2) = 0.81) has been obtained by comparing the NMR data with the results of the chemical analyses. The results suggest the possibility to perform a taxonomic study and/or a nutritional study on the basis of the ratio between protein and polysaccharide levels determined by NMR or chemical methodologies.

The importance of leaf- and litter-feeding invertebrates as sources of animal protein for the Amazonian Amerindians.

At least 32 Amerindian groups in the Amazon basin use terrestrial invertebrates as food. Leaf- and litter-consuming invertebrates provide the more important, underestimated food sources for many Amerindian groups. Further, litter-consuming earthworms are also an important food resource for the Ye'Kuana (also known as Makiritare) in the Alto Orinoco (Amazonas, Venezuela). By selecting these small invertebrates the Amerindians are choosing their animal food from those food webs in the rainforest which have the highest energy flow and which constitute the greatest renewable stock of readily available nutrients. Here we show that the consumption of leaf- and litter-feeding invertebrates as a means of recovering protein, fat and vitamins by the forest-living peoples offers a new perspective for the development of sustainable animal food production within the paradigm of biodiversity maintenance.

Modification of structure and digestibility of chestnut starch upon cooking: a solid state (13)C CP MAS NMR and enzymatic degradation study.

The modification of starch, which is the major component of the polysaccharide fraction of chestnuts (Castanea sativa), has been studied from the point of view of structure and digestibility to understand the modifications induced by cooking and, specifically, by the Maillard reaction. The study was carried out by enzymatic degradation kinetics, monitoring the glucose released upon time, and by solid state (13)C CP MAS NMR, which has the potential of monitoring the solid state phase changes occurring upon chemical modification due to the cooking process. Results obtained reveal that large changes are induced in the macromolecular structure of starchy materials and that these changes are correlated with changes of digestibility in terms of enzymatic degradation resistance. In the system studied, the extension of the Maillard reaction is not such as to exert a significant influence on structure and/or digestibility of chestnut starch.

A physico-chemical study on the polysaccharide ulvan from hot water extraction of the macroalga Ulva.

Results of a study on the solution behaviour of the cell-wall polysaccharide named ulvan obtained from hot water extraction of a flour of Ulva 'rigida' are reported. In particular the spectroscopic properties and ion binding capacity of this charged polysaccharide were studied by circular dichroism and isothermal microcalorimetric titrations in order to gain information on the potential exploitation of this low cost biomass. A marked tendency of this polysaccharide to uptake water was evidenced by studying the proton spin-lattice relaxation times of the solvent, T1, embedded in this highly charged polysaccharide.

Intake of fatty acids in western Europe with emphasis on trans fatty acids: the TRANSFAIR Study.

OBJECTIVE: To assess the intake of trans fatty acids (TFA) and other fatty acids in 14 Western European countries. DESIGN AND SUBJECTS: A maximum of 100 foods per country were sampled and centrally analysed. Each country calculated the intake of individual trans and other fatty acids, clusters of fatty acids and total fat in adults and/or the total population using the best available national food consumption data set. RESULTS: A wide variation was observed in the intake of total fat and (clusters) of fatty acids in absolute amounts. The variation in proportion of energy derived from total fat and from clusters of fatty acids was less. Only in Finland, Italy, Norway and Portugal total fat did provide on average less than 35% of energy intake. Saturated fatty acids (SFA) provided on average between 10% and 19% of total energy intake, with the lowest contribution in most Mediterranean countries. TFA intake ranged from 0.5% (Greece, Italy) to 2.1% (Iceland) of energy intake among men and from 0.8% (Greece) to 1.9% among women (Iceland) (1.2-6.7 g/d and 1.7-4.1 g/d, respectively). The TFA intake was lowest in Mediterranean countries (0.5-0.8 en%) but was also below 1% of energy in Finland and Germany. Moderate intakes were seen in Belgium, The Netherlands, Norway and UK and highest intake in Iceland. Trans isomers of C18:1 were the most TFA in the diet. Monounsaturated fatty acids contributed 9-12% of mean daily energy intake (except for Greece, nearly 18%) and polyunsaturated fatty acids 3-7%. CONCLUSION: The current intake of TFA in most Western European countries does not appear to be a reason for major concern. In several countries a considerable proportion of energy was derived from SFA. It would therefore be prudent to reduce intake of all cholesterol-raising fatty acids, TFA included.

Maillard reaction in mild-based foods: nutritional consequences.

Chemical reactions occurring during industrial treatments or storage foods can lead to the formation of epsilon-deoxyketosyl compounds, the Amadori products. Food protein value can be adversely affected by these reactions, and in particular lysine, an essential amino acid having on its side chain a free amino group, can be converted to nonbioavailable N-substituted lysine or blocked lysine. by acid hydrolysis of epsilon-deoxyketosyl compounds, furosine is formed. In this paper furosine prepared from milk-based commercial products has been evaluated by use of a recently developed HPLC method using a microbore column and phosphate buffer as the mobile phase at controlled temperature. Furosine levels have been used, together with protein, total amino acids, and lysine content, as an estimate of protein quality of a few different products such as cooked-cream dessert, yogurt mousse, white chocolate, milk chocolate, milk chocolate with a soft nougat and caramel center, milk chocolate with a whipped white center, chocolate spread, part-skim milk tablets, milk-based dietetic meals, and baby foods. The protein content of the analyzed products ranged from 34.3 gxkg(-1) (milk nougat) to 188.4 g x kg(-1) (milk tablets). The Maillard reaction caused a loss in available lysine that varied from 2.5% (cooked cream) to 36.2% (condensed milk). The contribution to the lysine average daily requirement is heavily affected by this reaction and varied from 13% (milk tablets and soft nougat) to 61% (dietetic meal). Variable results were also obtained for the other essential amino acids.

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.

Structural Modification and Bioavailability of Starch Components As Related to the Extent of Maillard Reaction: An Enzymatic Degradation and a Solid-State (13)C CPMAS NMR Study.

Starch and starch components, amylose and amylopectin, from potato, have been studied in order to understand the modifications, induced by different levels of the Maillard reaction occurring in the presence of amino acids (L-lysine in this study), in the macromolecular structure and digestibility. Structural characterization was performed by (13)C CPMAS NMR, and differences in the bioavailability of these polymers were studied by enzymatic degradation kinetics. Results obtained reveal that changes are induced by the Maillard reaction, whose occurrence has been verified and measured by the furosine (epsilon-N-2-furoylmethyl-L-lysine) evaluation, on the macromolecular structure of starchy materials and on their enzymatic susceptibility. Lysine seems to act as a disordering agent; a loss of crystallinity is evident for starch and amylopectin and, in particular, for amylose. Finally, within the same sample, as the lysine concentration increases, the polymer digestibility decreases, confirming that structural organization is not the only determinant of starch digestibility.

Analysis of epsilon-N-2-furoylmethyl-L-lysine (furosine) in dried milk by capillary electrophoresis with controlled electroosmotic flow using N,N,N',N'-tetramethyl-1,3-butanediamine in the running electrolyte solution.

The electrophoresis of epsilon-N-2-furoylmethyl-L-lysine (furosine) was studied in an attempt to develop a method for the identification and quantitation of this compound in processed food. The effect of pH and composition of electrolyte solution on both the electrophoretic migration of furosine and the electroosmotic flow in a bare fused-silica capillary of 75 mu m internal diameter was investigated. We demonstrate that the addition, to the running electrolyte solution, of N,N,N',N'-tetramethyl-1,3-butanediamine (TMBD) at concentrations ranging from 20 to 80 mM improves peak efficiency and can be used to modulate the migration time of furosine by controlling the electroosmotic flow which is reversed from cathodic to anodic. In a sample of dried milk subjected to a long period of storage under controlled conditions, furosine could be efficiently and reproducibly separated and quantitated by employing as the running electrolyte 60 mM TMBD titrated to pH 2.5. Capillary electrophoresis is a promising technique for the rapid identification and quantitation of furosine in processed food.

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

A 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.

High-performance liquid chromatographic method for the simultaneous determination of tocopherols, carotenes, and retinol and its geometric isomers in Italian cheeses.

In the present study we describe a high-performance liquid chromatographic method for the simultaneous determination of alpha-, beta-, gamma- and delta-tocopherol, cis and trans isomers of retinol, and total carotenes in different Italian cheeses. The method involves sample extraction and saponification followed by normal-phase high-performance liquid chromatography (HPLC). Monitoring of the absorbance and fluorescence is achieved using a programmable spectrophotometer and a programmable spectrofluorometer connected in series. The proposed method, which has the advantage of being able to evaluate simultaneously the fat-soluble vitamins considered by us in this work, has been applied to some Italian cheeses (Percorino romano, Taleggio, Provolone, and Caciotta) and milk samples (cows', goats', and sheep milk). The HPLC analytical procedure provides excellent reproducibility of results and is less subject to interferences from the sample matrix than wet chemical techniques. These factors combine to make the simultaneous determination of alpha-, beta-, gamma-, and delta-tocopherol, cis and trans isomers of retinol, and total carotenes by HPLC a practical technique for routine quality control and chemical and nutritional research applications.

In vitro model for the evaluation of toxicity and antinutritional effects of sulphites.

The food preservatives, sulphur dioxide and its salts, are known to present some toxic, mutagenic and antinutritional effects; in fact they interact with a number of nutrients, e.g. some vitamins, notably thiamine (Th) and folic acid (FA). The effect of different concentrations of sodium bisulphite in cell culture media has been studied in vitro on a human cell line, HEp-2, deriving from a carcinoma of the larynx. Moreover, the sulphites have been tested with different levels of Th and FA with the aim of elucidating how much the cellular response depended on either the anti-nutritional effect or the toxicity of sulphites. Cell growth has been taken as an index of cytotoxicity and measured both as total protein content and as colony-forming ability. With no Th and FA in the culture medium, a clear decrease of cell growth was observed either with or without addition of sodium bisulphite. A dose-dependent reduction of protein content was detected in cells treated with 10, 50, 100, 200, 250 or 500 microM sodium bisulphite. Moreover, when the cells were treated with 10 or 100 microM of this compound, the colony-forming ability was reduced both in number and colony size. As far as the interaction of the two vitamins with sodium bisulphite is concerned, when these nutrients were present in the medium at 0.5, 1.0, 1.5, 2.0 or 2.5 mg/l, a similar growth profile, determined from their concentration, was observed in treated and control cells, the growth levels being affected by the sodium bisulphite contents. At higher levels of Th and FA, the growth index was still increasing only in treated cells, this phenomenon being particularly evident in cultures treated with 200 microM sodium bisulphite. The colony-forming ability was reduced in controls but still increased in treated cells at the highest concentration of vitamins.

Evaluation of an HPLC method for the determination of sulphiting agents in foods.

A method based upon a combination of a modified Monier-Williams procedure and an HPLC separation and quantitation of sulphite, has been developed. Its efficiency has been tested, in comparison with the Monier-Williams method, for the SO2 recovery in various foods. Desorption of SO2 from different matrices is obtained by distillation in strongly acid solution. Gaseous SO2, collected and oxidized to sulphate with hydrogen peroxide, is neutralized with sodium hydroxide. The neutralized solutions are diluted and injected by an autosampling injector into an HPLC apparatus consisting of a strong anion exchange column, eluted with a potassium hydrogen phthalate solution (0.15 g/l, pH 5.7) at a 3 ml/min flow rate and detected at 280 nm by an UV spectrophotometer. The combined method shows a good detection limit as well as high chromatographic resolution, avoiding potential interference of other volatile compounds. It is also time-saving and utilized basic laboratory equipment.