Effect of Interspecific Yeast Hybrids for Secondary In-Bottle Alcoholic Fermentation of English Sparkling Wines

In sparkling winemaking, only a few yeast strains are regularly used for the secondary in-bottle alcoholic fermentation (SiBAF). Recently, advances in yeast development programs have yielded new breeds of interspecific wine yeast hybrids that ferment efficiently while producing novel flavors and aromas. In this work, the chemical and sensorial impacts of the use of interspecific yeast hybrids for SiBAF were studied using three commercial English base wines prepared for SiBAF using two commercial and four novel interspecific hybrids. After 12 months of lees aging, the chemical and macromolecular composition, phenolic profile, foaming, viscosity and sensory properties of the resulting 13 wines were assessed. Chemically, the yeast strains did not result in significant differences in the main wine parameters, while some differences in their macromolecular contents and sensory characteristics were noticeable. The foamability was mostly unaffected by the strain used; however, some effect on the foam stability was noticeable, likely due to the differences in polysaccharides released into the wines by the yeast strains. The wines exhibited different sensory characteristics in terms of aroma and bouquet, balance, finish, overall liking and preference, but these were mostly attributable to the differences in the base wines rather than the strain used for SiBAF. Novel interspecific yeast hybrids can be used for the elaboration of sparkling wines, as they provided wines with chemical characteristics, flavor and aroma attributes similar to those of commonly used commercial Saccharomyces cerevisiae strains

Effect of ageing time on consumer-perceived quality of Italian Simmental beef

The aim of the experiment was to provide an objective indication on the optimal ageing time of meat from ItalianSimmental (IS) young bulls, the most important commercial category of the breed. The research was carried out on 10young bulls slaughtered at the average weight of 688 kg (SE: 7.3 kg). The right side of each carcass was stored for 7days and the left one for further 7 days, at normal refrigeration temperatures. At the end of the ageing period, the sideswere sampled at the loin for meat pH, color, cooking loss and shear force measurement. A central location, affective testinvolving 74 consumers was carried out to measure the degree of liking for grilled beef aged 7 or 14 days.The pH and color parameters were not significantly affected by the duration of post-mortem storage, while cooking lossincreased (31.4 vs 32.6 %; P<0.05) and shear force values diminished (56.7 vs 46.8 N; P< 0.01) when ageing timeincreased from 7 to 14 days. The degree of liking by the untrained respondents for the two types of cooked meat wasdifferent, considering that consumers gave the highest hedonistic scores to beef aged 14 days. Tenderness was the sensoryattribute that allowed the best discrimination between beef stored for periods of different length. In fact, while thedifference between 14-day-aged and 7-day-aged beef for flavour ratings (7.0 vs 6.9) did not reach the threshold of significance,the former meat was perceived as significantly finer than the latter regarding tenderness (6.5 vs 5.6; P= 0.01)and marginally preferred in overall terms (6.9 vs 6.5; P= 0.07). The classification test, carried out at the end of the quantitativetest by asking consumers to select from a list the most appropriate attributes describing the stimuli associatedwith meat consumption, confirmed the effectiveness of texture attributes in ranking different-aged beef acceptability. Infact, the number of ticks reported for chewiness and juiciness descriptors were different for the two types of meat: the14-day-aged beef was perceived as easier to chew (57 vs 34 ticks) and juicier (42 vs 24) than the shortest-aged beef.Ageing for 14 days should be recommended as a process control point for the beef industry to improve consumer acceptanceof IS young bull beef

Biology of telenomus pachycoris (Hymenoptera: Scelionidae), a parasitoid of eggs of pachycoris torridus (Hemiptera: Scutelleridae): the effects of egg age, exposure time, and temperature

Telenomus pachycoris (Johnson) (Hymenoptera: Scelionidae) is a parasitoid of eggs of Pachycoris torridus (Scopoli) (Hemiptera: Scutelleridae), a main pest of physic nut (Jatropha curcas L.; Euphorbiaceae). The objective of this work was to know the biology of T. pachycoris in P. torridus eggs under various conditions in order to develop a rearing technique for this parasitoid in the laboratory. We offered eggs of P. torridus to T. pachycoris during 4 exposition periods (6, 12, 18, and 24 h), as well as eggs of different ages (1 to 11 d), to evaluate, in both experiments, the number of parasitized eggs, duration of the egg-to-adult period, percentage of emergence, and sex ratio. We also evaluated the effect of constant temperatures (18, 20, 22, 25, 28, and 30 °C) and determined the duration of the egg-to-adult period, percentage of emergence, and sex ratio and estimated the thermal requirements and the number of generations per yr of T. pachycoris at each temperature. Parasitism of eggs was the highest at 12 h of exposure. Eggs up to 3 d old were the most parasitized, and the parasitism was zero on day 11. The duration of the egg-to-adult period was inversely proportional to temperature, ranging from 33.6 d at 18 °C to 9.8 d at 30 °C. The threshold temperature estimated for T. pachycoris was 12.9 °C, and the estimated thermal constant was 163.9 degree-days. The number of generations of T. pachycoris ranged from 11.3 to 38.1 per yr at 18 and 30 °C, respectively. The results may contribute to developing techniques for rearing T. pachycoris in the laboratory.Facultad de Ciencias Naturales y Muse

Biology of telenomus pachycoris (Hymenoptera: Scelionidae), a parasitoid of eggs of pachycoris torridus (Hemiptera: Scutelleridae): the effects of egg age, exposure time, and temperature

Telenomus pachycoris (Johnson) (Hymenoptera: Scelionidae) is a parasitoid of eggs of Pachycoris torridus (Scopoli) (Hemiptera: Scutelleridae), a main pest of physic nut (Jatropha curcas L.; Euphorbiaceae). The objective of this work was to know the biology of T. pachycoris in P. torridus eggs under various conditions in order to develop a rearing technique for this parasitoid in the laboratory. We offered eggs of P. torridus to T. pachycoris during 4 exposition periods (6, 12, 18, and 24 h), as well as eggs of different ages (1 to 11 d), to evaluate, in both experiments, the number of parasitized eggs, duration of the egg-to-adult period, percentage of emergence, and sex ratio. We also evaluated the effect of constant temperatures (18, 20, 22, 25, 28, and 30 °C) and determined the duration of the egg-to-adult period, percentage of emergence, and sex ratio and estimated the thermal requirements and the number of generations per yr of T. pachycoris at each temperature. Parasitism of eggs was the highest at 12 h of exposure. Eggs up to 3 d old were the most parasitized, and the parasitism was zero on day 11. The duration of the egg-to-adult period was inversely proportional to temperature, ranging from 33.6 d at 18 °C to 9.8 d at 30 °C. The threshold temperature estimated for T. pachycoris was 12.9 °C, and the estimated thermal constant was 163.9 degree-days. The number of generations of T. pachycoris ranged from 11.3 to 38.1 per yr at 18 and 30 °C, respectively. The results may contribute to developing techniques for rearing T. pachycoris in the laboratory.Facultad de Ciencias Naturales y Muse