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

The Author after having examined the present acquirements of the native enzymes of the grapes, summarizes the enologic uses of the enzyme preparations at various degrees of purity with the point of view of the influence on the organoleptic (color, aromatic composition) ad rheologic (yield, filtrability) characteristics of the musts and wines besides some microbiological implications. Subsequently the Author exposes the original results extrapolated from the pilot and industrial trials on the use of different hydrolases (pectinase, cellulase, hemicellulase, acid protease, xylanase) on the wine-making processes (traditional red wine-making, heating red-wine-making, white wine-making). From the comparison of the last data with those of the reference are drawed conclusive considerations on some aspects of the subject.

The mutagenicity of sixty pesticides was investigated in three strains of Saccharomyces cerevisiae using reversion from histidine and methionine auxotrophy as a measure of the induced mutation. Mutagenesis was observed in twenty three compounds; the strains employed exhibit different susceptibility to the mutagenic action. In view of the data obtained the possible mechanisms of action of the different class of compounds are discussed.

Referring to a typical plant for milk sterilization fixed and variable costs are evaluated at different heat recovery levels. The results of the analysis indicate that the transformation cost significantly decreases increasing heat recovery, and reaches a minimum at 90% heat regeneration. Milk sterilization apparatuses now on the market are characterized by a heat recovery between 40 and 85%.

This review analyses the possibility to increase fishery production in order to satisfy the always increasing requirement of protein food. The most important chemical and nutritional chracteristics of fish and its by-products, as well as the preservation and elaboration technologies are reported. Some new or unusual fish utilization processes, as protein concentrates, extracts and spread pastes productions, are proposed as human food new sources.

Forty-five samples of honey produced in Emilia-Romagna between June and September 1974 have been subjected to gaschromatography to check for the presence of residues of chlororganic and phosphorganic phytodrugs. Residues of chlororganic phytodrugs in appreciable amounts have been found to be present in 11 samples only, more precisely lindane has been reported in 6 samples, aldrin in 4 samples, DDT in 4 samples, DDD and dieldrin respectively in one sample only. The higher concentration for DDT has been 0,04 ppm. No residues of phosphorganic phytodrugs have been found to be present in any of the samples examined. As the presence of residue has been observed only in a small number of samples and low concentration have been found, we belive that the problem of honey pollution by phytodrug residues is a minor one, even when related to the situation of foods in general.

Changes in sugars and polyols content of fruits and leaves of three cultivar of peach, from fruit set to over maturity, have been studied. Sucrose, glucose, fructose and sorbitol were found both in leaves and in fruits. In fruits, inositol and galactose were also found but only in traces. Redhaven fruits show the greatest total sugars content (sorbitol included) (866 mg/g.d.m.)followed in order by Favorita and Prodigiosa ones (771 and 694 mg/g.d.m.) For Redhaven and Favorita fruits, at harvest matuity, the sugar present in greatest amount was sucrose followed in order by glucose, fructose and sorbitol. On the contrary, in Prodigiosa fruits the order was sucrose, sorbitol, fructose and glucose. In the leaves of three cultivar, the compound present in the greatest amount was sorbitol followed by sucrose, glucose and fructose. The sucrose decrease in leaves during fruit growth could confirm that the disaccharide is the main sugar transported from the leaves to the fruits.

A method is proposed for the differentiation of natural red wines from those obtained by addition of oenocyanine to white wines. The procedure is based on the determination of tannin phenolics and nontannin phenolics by selective precipitation with methyl cellulose and subsequent estimation of the intensity of absorption at 450 nm and 520 nm. The sum of ratio: mg/1 non tannin phenolics/absorption at 450 nm X 1000 and mg/1 tannin phenolics/absorption at 520 nm X 1000, furnishes values which are in correlation with the origin of two wines and such as to consent their differentiation.

The amount and the circadian distribution of spontaneous activity in the rat are influenced by a number of factors, whose importance and interrelationships are still deeply discussed. In order to check the reliability of previous studies about the effects of meal-eating on the spontaneous activity (wheel running) of rats of our Sprague-Dawley strain, the adjustment to the modifications of the normal day-night cycle and of the normal nocturnal feeding rhythm have been controlled. Reversing the normal light and dark periods caused the rats, after a 24 hours period, to lower and to irregularly distribute their spontaneous activity. Rats shifted their pattern of maximal activity by 12 hours in the new period of darkness in about five days, and showed to have completely fixed the new reversed running habit. Also feeding habits changed in a similar way, but more slowly. The levels of mean daily activity did not change. In a second experiment, rats, received food during light hours, and were deprived during dark hours. Their activity increased considerably and irregularly during dark hours, while a very slight rise of wheel running was shown during light hours. Body weight gain and food consumption were similar to those of the control group. These results slightly differ from those obtained using other rat strains, and are an interesting example of reinforcement of a spontaneous behavior resulting more from the light-dark cycle than from cues provided by food deprivation.