The addition of Propionibacterium freudenreichii to Raclette cheese induces biochemical changes and enhances flavor development

Two mixtures of Propionibacterium freudenreichii commercial strains were tested as adjunct cultures in pasteurized milk Raclette cheese to investigate the ability of propionibacteria (PAB) to enhance flavor development. Cheese flavor was assessed by a trained sensory panel, and levels of free amino acids, free fatty acids, and volatile compounds were determined. The PAB level showed a 1.4 log increase within the ripening period (12 weeks at 11 degrees C). Eye formation, which was not desired, was not observed in PAB cheeses. PAB fermented lactate to acetate and propionate and produced fatty acids by lipolysis, branched chain volatile compounds derived from isoleucine and leucine catabolism and some esters. One of the experimental cheeses received the highest scores for odor and flavor intensity and was characterized by higher frequencies of detection for some minor notes ("propionic"and "whey" odor, "sweet" taste). PAB can therefore be considered as potential adjunct cultures to enhance or modify cheese flavor development.     

Exporting,Foreign Direct Investment,and Wages: Evidence from the Canadian Manufacturing Sector

Do exporters and foreign‐controlled establishments pay their workers higher wages than non‐exporters and domestic‐controlled establishments? This paper draws on an employer–employee data set to explore the existence of exporter and foreign‐owned wage premiums in the Canadian manufacturing sector. Results from wage regression models reveal that, on the whole, exporters and foreign‐controlled plants do pay higher wages than non‐exporters and domestic‐controlled plants. These results hold even after controlling for other plant and worker characteristics, although the wage differentials are substantially smaller. Furthermore, while the impact of foreign ownership on wages is found to be widespread across industries and regions, that of exporting is not. At the industry level, the wage effects of export‐market participation are strongest for workers in plants belonging to scale‐based industries; regionally, they are strongest in Quebec and British Columbia.     

Time course and specificity of lipolysis in Swiss cheese

Controlling lipolysis in cheese is necessary to ensure the formation of desirable flavor. To get a better understanding of the mechanism of lipolysis in Swiss cheese, cheeses were manufactured with and without (control) the addition of Propionibacterium freudenreichii. Products of lipolysis were quantified throughout ripening. Half of the free fatty acids (FFA) released in milk (3.66 mg/g fat), in particular the short-chain FFA, were lost in the whey during curd drainage, whereas diglycerides and monoglycerides were retained within the curd. P. freudenreichii was responsible for the release of most FFA during ripening (10.84 and 0.39 mg/g fat in propionibacteria-containing and control cheeses, respectively). Indices of lipolysis displayed low specificity. All types of FFA were released, but butyric and palmitic acids more significantly, which could be due to a low sn-1,3 regioselectivity. All glycerides were hydrolyzed in the following order: monoglycerides>diglycerides>triglycerides. The results of this study show the quantitative and qualitative contributions of the different lipolytic agents to Swiss cheese lipolysis.     

Physico-Chemical Changes In Cladodes (Nopalitos) From Cultivated And Wild Cacti (Opuntia spp.)

Physico-chemical and nutritional composition from four different nopalitos (young cladodes from cacti): Blanco sin Espinas, Blanco con Espinas, Verde Valtierrilla (cultivated materials) and a wild material from the central region of México were studied at different sizes of harvesting. The first three are commercial crops. None of the tested materials exhibited superior characteristics in all of the evaluated parameters in relation to each one of them. In various cases properties of the wild crop were comparable, if not superior, to commercial ones. Some important changes were observed in total soluble solids, water content, texture, acidity and pH as affected by size of cladode and specific crop. Most cladode samples appear to be a good source of β-carotene and lutein. The presence of these compounds is important for human nutraceutical purposes.     

Composition, Digestibility and Application in Breadmaking of Banana Flour

Banana flour (BF) was obtained from unripe banana (Musa paradisiacal L.) and characterized in its chemical composition. Experimental bread was formulated with BF flour and the product was studied regarding chemical composition, available starch (AS), resistant starch (RS) and rate of starch digestion in vitro. The chemical composition of BF showed that total starch (73.36%) and dietary fiber (14.52%) were the highest constituents. Of the total starch, available starch was 56.29% and resistant starch 17.50%. BF bread had higher protein and total starch content than control bread, but the first had higher lipid amount. Appreciable differences were found in available, resistant starch and indigestible fraction between the bread studied, since BF bread showed higher resistant starch and indigestible fraction content. HI-based predicted glycemic index for the BF bread was 65.08%, which was significantly lower than control bread (81.88%), suggesting a “slow carbohydrate” feature for the BF-based goods. Results revealed BF as a potential ingredient for bakery products containing slowly digestible carbohydrates.     

Additions of landscape metrics improve predictions of occurrence of species distribution models

Species distribution models are used to aid our understanding of the processes driving the spatial patterns of species’ habitats. This approach has received criticism, however, largely because it neglects landscape metrics. We examined the relative impacts of landscape predictors on the accuracy of habitat models by constructing distribution models at regional scales incorporating environmental variables (climate, topography, vegetation, and soil types) and secondary species occurrence data, and using them to predict the occurrence of 36 species in 15 forest fragments where we conducted rapid surveys. We then selected six landscape predictors at the landscape scale and ran general linear models of species presence/absence with either a single scale predictor (the probabilities of occurrence of the distribution models or landscape variables) or multiple scale predictors (distribution models + one landscape variable). Our results indicated that distribution models alone had poor predictive abilities but were improved when landscape predictors were added; the species responses were not, however, similar to the multiple scale predictors. Our study thus highlights the importance of considering landscape metrics to generate more accurate habitat suitability models.