Effect of selection for growth rate on biochemical, quality and texture characteristics of meat from rabbits

Biochemical characteristics, including myosin heavy chain I (MHC-I) percentage, isocitrate dehydrogenase and aldolase activities, meat quality traits and instrumental texture properties of rabbits selected for different growth rates were studied. The animals of the control (C) group (7th generation; n=60) were raised in parallel with those of selection (S) group (21st generation; n=60). Carcass weights (1230.1 ± 19.8 and 1348.3 ± 20.1 g, for C and S, respectively) and perirenal and scapular fat content differed significantly (P<0.01) between the two groups. Water holding capacity was expressed as the percentage of pressure released water and was significantly different (P<0.05) between groups C and S (33.29% and 35.57%). MHC-I percentage and aldolase activity also differed significantly (P<0.05) between groups, group C showing higher oxidative traits than group S (MHC-I: 12.5% and 9.8%; aldolase: 597.11 and 636.83 UI/g muscle). Texture properties from the Warner-Bratzler test showed higher (P<0.001) shear firmness for loin in the S group (1.69 kg/s cm²) than in the C group (1.34 kg/s cm²). In addition, the texture profile analysis indicated that chewiness, gumminess and hardness were also higher in the S group (P<0.01). In conclusion, the results confirmed a positive effect of the selection on productive traits and a negative effect on instrumental texture properties and on the water holding capacity of the meat.     

Effect of addition of sucrose and aspartame on the compression resistance of hydrocolloids gels

The effect of adding sucrose (5–25% w/w) and aspartame (0.04–0.16% w/w) on the compression resistance of three hydrocolloid gelled systems: κ‐carrageenan, gellan gum and κ‐carrageenan/locust bean gum at three different concentrations (0.3, 0.75 and 1.2% w/w) was studied. Sucrose addition increased true rupture stress in the three‐gelled systems, this effect being stronger in gellan gels. The deformability modulus increased with sucrose concentration in gellan gels, but not in the other systems. Rupture stress and deformability modulus increased with the addition of sucrose only in the harder gels (0.75 and 1.2% w/w). The effect of sucrose addition on the true rupture strain was significant but, in general, not important, mainly for lower gum concentrations. Aspartame addition did not affect the compression parameters.     

Effects of α s1-casein (CSN1S1) and κ-casein (CSN3) genotypes on milk coagulation properties in Murciano-Granadina goats

The effects of the caprine α s1-casein (CSN1S1) polymorphisms on milk quality and cheese yield have been widely studied in French and Italian goat breeds. Much less is known about the consequences of κ-casein (CSN3) genotype on the technological and coagulation properties of goat milk. In the current study, we have performed an association analysis between polymorphisms at the goat CSN1S1 and CSN3 genes and milk coagulation (rennet coagulation time, curdling rate and curd firmness) and technological (time to cutting of curd and cheese yield) properties. In this analysis, we have included 193 records from 74 Murciano-Granadina goats (with genotypes constituted by different combinations of alleles B, E and F of the gene CSN1S1 and alleles A and B of the gene CSN3) distributed in three herds, which were collected bimonthly during a whole lactation. Data analysis, using a linear mixed model for repeated observations, revealed significant associations between CSN1S1 genotypes and the rate of the curdling process. In this way, milk from EE goats had a significantly higher curdling rate than milk from BB individuals (P<0?·05). Contrary to previous experiments performed in French breeds, cheese yield was not significantly different in BB, EE and EF goats. Moreover, we have shown that CSN3 genotype has a significant effect on the rennet coagulation time (BB>AB, P<0?·05) but not on cheese yield. No interaction between the CSN1S1 and CSN3 genotypes was observed.     

Inactivation of Salmonella enterica serovar Enteritidis on shell eggs by ozone and UV radiation

The presence of Salmonella enterica serovar Enteritidis in shell eggs has serious public health implications. Several treatments have been developed to control Salmonella on eggs with mixed results. Currently, there is a need for time-saving, economical, and effective egg sanitization treatments. In this study, shell eggs externally contaminated with Salmonella (8.0 x 10(5) to 4.0 x 10(6) CFU/g of eggshell) were treated with gaseous ozone (O3) at 0 to 15 lb/in2 gauge for 0 to 20 min. In other experiments, contaminated shell eggs were exposed to UV radiation at 100 to 2,500 microW/cm2 for 0 to 5 min. Treatment combination included exposing contaminated eggs to UV (1,500 to 2,500 microW/cm2) for 1 min, followed by ozone at 5 lb/in2 gauge for 1 min. Eggs that were (i) noncontaminated and untreated, (ii) contaminated and untreated, and (iii) contaminated and treated with air were used as controls. Results indicated that treating shell eggs with ozone or UV, separately or in combination, significantly (P < 0.05) reduced Salmonella on shell eggs. For example, contaminated eggs treated with ozone at 4 to 8 degrees C and 15 lb/in2 gauge for 10 min or with UV (1,500 to 2,500 microW/cm2) at 22 to 25 degrees C for 5 min produced 5.9- or 4.3-log microbial reductions or more, respectively, when compared with contaminated untreated controls. Combinations including UV followed by ozone treatment resulted in synergistic inactivation of Salmonella by 4.6 log units or more in about 2 min of total treatment time. Salmonella was effectively inactivated on shell eggs in a short time and at low temperature with the use of a combination of UV radiation and ozone.     

Changes in the non-structural carbohydrates associated with the field drying of oat forage

Two trials were conducted to determine the sugars, fructans and starch in oat plants (Avena sativa L) and the changes occurring in these carbohydrate fractions during field drying in the haymaking process. The composition of oat herbage in non-structural carbohydrates varied markedly between years; the contents of sugars, fractals and starch in both leaf blade and non-leaf blade materials being nether in 1990–1991 than in 1991–1992. Field drying produced a significant decrease (P < 0.05) in the amount of soluble carbohydrates. For the whole aerial plant parts, the decline in the fructans concentration ranged between 42.8 and 38.2% and that of sugars between 16.5 and 5.8%. The total losses of sugars and fractions in hay, expressed as losses of dry matter, ranged from 88 to 63 g kg^?1 depending on the year.     

The effect of field drying on the non-structural carbohydrate composition in vetch hay

Common vetch (Vicia sativa L) was harvested and allowed to dry in the open air. The composition of fresh forage in non-structural carbohydrates varied markedly between years, the contents of sugars and starch in both leaves and stems being much higher in 1990-91 than 1991-92. Field drying produced a significant decrease in the amounts of these carbohydrates. The total losses of sugars and starch in hay, expressed as losses of dry matter, ranged from 28 to 15 g kg^-1, depending on the year.     

High-performance liquid chromatography multiresidue method for the determination of N-methyl carbamates in fruit and vegetable juices

A rapid multiresidue method has been developed for the analysis of N-methylcarbamate insecticides (oxamyl, methomyl, propoxur, carbofuran, carbaryl, and methiocarb) in fruit and vegetable juices. The method is based on the adsorption of the N-methyl carbamates in Florisil and the subsequent extraction of pesticides using a low volume of acetone. Residue levels in juice were determined by reversed-phase high-performance liquid chromatography with fluorescence detection after postcolumn derivatization. The separation of carbamates is performed on a C8 column with water-methanol as mobile phase. Recovery studies were performed at 500-, 100-, and 10-ng/ml fortification levels, and average recoveries obtained for carbamates ranged from 79 to 109%, with relative standard deviations between 1.4 and 9.9%. The method was found to be linear over the range assayed from 10 to 1,000 ng/ml, and the detection limits for carbamates varied from 0.8 to 1.9 ng/ml.     

Space phasor theory and control of multiphase machines through their decoupling into equivalent three-phase machines

This paper first introduces the space phasor theory from a general mathematical viewpoint and, above all, from a physical one as well. The theory is then applied to the particular case of constant airgap multiphase machines (MMs) fed by arbitrary voltage waveforms. It is mathematically proven, and thereafter checked by simulations too, that these machines can be split into a set of equivalent three-phase machines mechanically coupled but electrically independent. This electrical decoupling leads immediately to develop the very fast torque control schemes of the MMs. All of them boil down to a mere extension of those already used in the homologous three-phase machines.     

Effect of the Nucleophile’s Nature on Chloroacetanilide Herbicides Cleavage Reaction Mechanism. A DFT Study

In this study, the degradation mechanism of chloroacetanilide herbicides in the presence of four different nucleophiles, namely: Br⁻, I⁻, HS⁻, and S₂O₃⁻², was theoretically evaluated using the dispersion-corrected hybrid functional wB97XD and the DGDZVP as a basis set. The comparison of computed activation energies with experimental data shows an excellent correlation (R² = 0.98 for alachlor and 0.97 for propachlor). The results suggest that the best nucleophiles are those where a sulfur atom performs the nucleophilic attack, whereas the other species are less reactive. Furthermore, it was observed that the different R groups of chloroacetanilide herbicides have a negligible effect on the activation energy of the process. Further insights into the mechanism show that geometrical changes and electronic rearrangements contribute 60% and 40% of the activation energy, respectively. A deeper analysis of the reaction coordinate was conducted, employing the evolution chemical potential, hardness, and electrophilicity index, as well as the electronic flux. The charge analysis shows that the electron density of chlorine increases as the nucleophilic attack occurs. Finally, NBO analysis indicates that the nucleophilic substitution in chloroacetanilides is an asynchronous process with a late transition state for all models except for the case of the iodide attack, which occurs through an early transition state in the reaction.     

Changes in lipid fractions and sensory properties of Idiazabal cheese induced by lipase addition

This work studied the addition of an adequate lipase to enhance lipolysis reactions and the development of piquant flavour and sharp odour in Idiazabal cheese, as an alternative to the use of lamb rennet paste. Cheeses were manufactured from bulk raw ewes' milk in 50 l vats with commercial bovine rennet and 80 lipase units of pregastric or 180 lipase units of fungal lipase and ripened for 180 days. A higher lipolytic activity was induced by lipase addition promoting strong changes in odour and flavour attributes. Both fungal and pregastric lipases increased the content of total free fatty acids (FFA), but the fungal lipase released mainly medium- and long-chain FFA. In contrast, the pregastric lipase preferably released short-chain FFA. Diglyceride (DG) content was considerably higher in cheeses made with added pregastric lipase compared with those made with fungal lipase or with no lipase. Monoglycerides (MG) were detected only in cheeses made with either lipase added, reaching comparable concentrations after ripening for 180 days. The cheeses made with pregastric lipase had the highest scores for odour and flavour intensity, and sharp and rennet odours, desirable attributes for the Idiazabal cheese made with lamb rennet paste. None of the texture attributes were significantly influenced by the concentrations of MG and DG in the cheeses made with either lipase. Thus, the pregastric lipase was more appropriate than the fungal lipase to develop a more traditionally-flavoured Idiazabal cheese.