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Crystalline and amorphous cellulose in dietary fibre from the green macroalga Ulva have been analysed using X-ray diffraction and enzymic methods. It is observed that the results predicted for the ulva cellulose by X-ray pattern are consistent with the enzymic hydrolysis results. Experiments revealed that crystallinity of Ulva cellulose can be increased with physio-chemical treatments.

Termites seri (especially Syntermes aculeosus soldiers) are collected extensively by Makiritare (or Ye'Kuana Indians in the Alto Orinoco) and consumed raw or after soaking in hot water (60°-80°C). They are gathered be means of "termite fishing" technique and then transported into a package called kukuruciu made with Musacean (Phenakospermum sp.) leaves. The solders of Syntermes constitute a food source of great nutritional value: high in proteins and essential amino acids such as trytophan, which is generally limiting in the food insects. Abundant are minerals such as iron and calcium together with micronutrients. Essential fatty acids are well represented. In general, heads of seri are better nutritionally featured than thorax and abdomens (not eaten by the Makiritare but comsumed by the Piaroa Indians). [ABSTRACT FROM AUTHOR]

Forty-five Siriana dairy goats were divided into three groups and assigned to three feeding treatments: i) grazing (G), ii) grazing plus 600 g of mixed barley and chickpeas grain per day (GBC), iii) grazing plus 600 g of mixed maize and broad beans per day (GMB). These grazing groups were compared to a control group (I) of 15 Siriana goats fed indoors a pasture hay plus 600 g of a commercial concentrate per day. Retinol concentrations of milk samples were determined and correlated with the herbage intake. Feeding treatments influenced all trans and total retinol concentrations significantly. Milk from treatment G contained the highest all-trans and total retinol concentrations, while milk from treatment I had the lowest values. The increase in total retinol concentration in milk of 20% and 30%, respectively, corresponded with the increase in green herbage intake, from zero in the I treatment to 381.7 g DM/day in the GBC and GMB treatments and 568.7 g DM/day in G treatment. From spring to winter the ratio between total retinol concentration and milk production (R/MP) showed an opposite trend in comparison to milk production: the more the milk production decreased, the more the R/MP ratio increased. The differences observed in summer and winter between grazing treatments were probably due to different herbage intake. The mean ingested herbage intake of the GMB group was 28% less than that of the G group, and 36% less than the GBC group. This low intake caused the R/MP ratio to decrease by 41% and 62% in the G and the GBC groups, respectively. In the spring the herbage intake was higher (ca. 39%) than in the other two seasons, but no differences were observed between treatments. The influence of feeding treatment observed on milk retinol concentration could be due to a difference in retinol precursor concentration in the animal diet and/or a difference in bioavailability of the precursors in the animal body. [ABSTRACT FROM AUTHOR]

Taurine, a free amino acid, was studied as natural compound of different typologies of milk: pasteurized, ultra-high temperature (UHT), microfiltered whole and semi-skimmed cow's milk; pasteurized and UHT goat's whole milk and raw buffalo's whole milk. Moreover, taurine contents in yoghurt from cow and goat's milk were evaluated. The data obtained in this research showed that no significant variations of taurine occurred in cow's milk subjected to different technological processes and between whole and semi-skimmed milk. The amount of taurine was less (p < 0.05) in cow's milk (0.60 mg/100 g) than in goat and buffalo's milk (6.55 and 7.32 mg/100 g, respectively). No significant differences in taurine occurred between goat and buffalo's samples. The amounts of taurine in yoghurt reflected, substantially, the content of this molecule in the milk of the relevant animal species. These results are noteworthy because data available in the literature on this molecule in commercial dairy products are old or few.

Cholesterol, vitamin E and vitamin A isomers, components of the unsaponifiable fraction, and lactose contents in Mozzarella di Bufala Campana PDO cheese have been studied during storage in different conditions: at 6-8 degrees C, and at room temperature (traditional habits). During cold storage there were no significant differences in the unsaponifiable compounds, while during storage at room temperature an increase of the 13-cis isomer and a decrease of all-trans-retinol were observed. Trans/cis-retinol isomerization, expressed as the Degree of Retinol Isomerization (13-cis/all-trans%) showed an increase in all samples during storage at room temperature following a linear correlation. The decrease of lactose content during storage was studied by a first-order differential relaxation equation. Apart from the traditional habits, consumers should be aware that, during storage at room temperature, the most important changes in the considered nutrients occur. These changes can be negative (vitamin A reduction) but also positive (lactose reduction).

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.

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 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.

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.