S & TA & NU. Rivista di scienza e tecnologia degli alimenti e di nutrizione umana最新文献

Pesticide residues may be present in vegetables and may affect human health. Processing and canning operations substantially reduce these residues and help to maintain them at acceptable levels. The percentage of removal depends on the type of vegetable, the type of pesticide used and the processing procdure applied. The effects of washing, blanching, peeling and juice extraction on the removal of some insecticide residues from different vegetables are described and discussed, also with regerence to the present day situation in Italy.

The presence of nonvitreous kernels in durum wheat adversely influences milling yield, protein content and pasta manufacturing quality of semolina. From the results obtained, we can infer that the proportion of these negative effects is related to the degree of nonvitreousness exhibited by the kernels. Consequently, to define nonvitreousness and to establish proper methods for its determination, we have to take into consideration not only the percent of nonvitreous kernels but also the degree of nonvitreousness exhibited.

An aminoacid index for protein quality evaluation is presented, using a new model of enzymatic digestion of proteins in vitro. The EUD index is obtained determining on the ultrafiltrate the available aminoacids after digestion with pepsin, trypsin, pancretin and erepsin in an Amicon ultrafiltration cell. A very high correlation is obtained between EUD index and the biological values of 10 protein or food protein samples. The experimental validity of this in vitro method allow his utilization for direct evaluation of protein quality instead of the more complicated and time consuming biological tests.

Several studies indicate that in rats changing the rhythm of feeding from nibbling to meal-eating results in hyperlipogenesis and higher body fat deposition. Among the factors influencing this phenomenon, the effects of age and duration of treatment are not yet clear. Male rats of 4, 6, 12 and 18 weeks have been meal-fed (two 1-hour meals per day) for 5, 10, 20 and 30 days. Pair-fed Nibblers were used as controls. Adipocyte diameters and number from epididymal adipose tissues were determined, and lipogenesis measured my glucose-U-14-C incorporation into lipids. The results show that cellularity, glucose-U-14-C incorporation into adipocyte lipids and CO2 and body fat deposition are not affected by short-term meal-eating treatment in growing animals. In the adult rats, only after 30 days do the parameters studied show significant higher values in the meal-eating animals. The results are discussed in view of the possible interrelationships among the different factors influencing animal response to modifications in feeding frequency.

In this article are described the most interting fields of research: biosynthesis of the flavours and flavour precursors. Last field of investigation useful for the indexes of quality are the works on the code of the flavours.

It has been defined, in a previous work, a procedure for the "head space" gas chromatographic analysis. This method allowed the separation of 17 volatile constituents, utilizing Porapak Q, either as trap or chromatographic adsorbent. A series of new experiences have improved this precedure, adopting as trap two polymers (Porapak Q, copolymer of the ethyl-vinyl-benzene divinyl-benzene; Tenax GC porous polymer 2,6-diphenyl-p-phenilene oxide) and two different chromatographic phases. Furthermore, it has been entirely modified the introduction of the sample into the gas chromatographic column simplifying the handling and improving the operative conditions (times and temperature of desorption). The analysis of the "head space" carried out on wines of different aromatic compositions (Riesling) and on wines at different degree of ageing (Rubesco), besides having allowed the separation of 61 volatile components, 27 of which have identified, has put in evidence the sensitivity of this procedure.

The heterogeneity of the buffalo k-casein, treated with 2-mercaptoethanol, has been estimated by disk gel-polyacrylamide electrophoresis on 428 caseins isolated from individual milks. The investigation showed six electrophoretic fractions: A, B, C, D, E, F, that, in ten buffalo farms considered formed ten different groups: ABCDEF; ABCDE; ABCEF; ABCE; BCDE; CDEF; BCE; CDE; CEF; and CE. The group ABCDE is the only that is present in all ten farms considered and presents on the whole, the greater number of observations (161). The fraction C is the most abundant. The investigation showed the heterogeneity of the gamma fraction, showing five electrophoretic fractions: A, B, C, D, E, that constitute the nine following groups; ABCDE; ABCD; BCDE; ABD; BCD; ABC; BD; BC and AB. At present a possible correlation to genetic factors seems hazardous.

The results of trials aimed to keep colour and firmness of frozen cauliflower during storage, by pretreatments based on Calcium salts and SO2 impregnation are referred here. Among the different procedures tested, that of introducing under vacuum gaseous SO2 at low pressure, followed by soaking in CaCl2 0,1 N solution has shown the best efficaceousness.

A research has been conducted on several hundreds of cultivars and selection lines of bread wheat to find out new varieties of better nutritive characteristics. For a coarse evaluation of protein quantity and quality, a screening method (dyebinding capacity, DBC) was utilized. On the same samples, nitrogen was determined also by the Kjeldahl method; in some cases aminoacids analysis was carried out. A very high correlation was found between protein content and DBC and, even higher in this case, between DBC and lysine content (in samples with a high DBC). In this way it has been possible to sort out a certain number of varieties of interest from a nutritive standpoint and in relation to their protein and essential amino acids contents. The importance of these findings is discussed.