Modeling the tryptic hydrolysis of pea proteins using an artificial neural network

Experimentally determined values for the degree of hydrolysis (DH) were used with an artificial neural network (ANN) model to predict the tryptic hydrolysis of a commercially available pea protein isolate at temperatures of 40, 45, and 50 °C. Analyses were conducted using the STATISTICA Neural Networks software on a personal computer. Input data were randomized to two sets: learning and testing. Differences between the experimental and calculated DH% were slight and ranged from 0.06% to 0.24%. The performance of the educated ANN was then tested by inputting temperatures ranging from 35 to 50 °C. Very strong correlations were found between calculated DH% values obtained from the ANN and those experimentally determined at all temperatures; the determination coefficients (R²) varied from 0.9958 to 0.9997. The results so obtained will be useful to reduce the time required in the design of enzymatic reactions involving food proteins.     

Plant‐oil‐based lubricants and hydraulic fluids

It is estimated that, at present, approximately 50% of all lubricants sold worldwide end up in the environment via total loss applications, volatility, spills or accidents. More than 95% of these materials are currently mineral oil based. In view of their high ecotoxicity and low biodegradability, mineral oil‐based lubricants constitute a considerable threat to the environment. In contrast, most lubricants and hydraulic fluids based on plant oils are rapidly and completely biodegradable and are of low ecotoxicity; moreover, lubricants based on plant oils display excellent tribological properties and generally have very high viscosity indices and flashpoints. However, in order to compete with mineral‐oil‐based products, some of their inherent disadvantages must be corrected, such as their sensitivity to hydrolysis and oxidative attack, and their behaviour at low temperatures. Various methods to improve the undesirable properties of native plant oils will be discussed. In parallel, government regulations that encourage or enforce the use of bio‐based fluids, at least in ecologically sensitive areas, will help to increase their market share. Using the numerous possibilities for selective breeding and/or chemical improvement of the double bond systems of natural fatty acids by increased R&D, the major obstacles regarding the use of plant‐based raw materials for the production of lubricant base fluids can be overcome and bio‐based fluids should expect a future with increasing market shares. Copyright © 2006 Society of Chemical Industry     

Approaches for reducing Salmonella in pork production

Salmonellosis is an important disease in humans and is associated with contaminated food, including pork products. Salmonella infection is invasive in humans, but it usually remains latent within the swine population, creating reservoirs for carcass contamination. Although abattoirs implement stringent procedures during carcass processing, some raw pork products still have Salmonella contamination. To reduce the presence of Salmonella, a dynamic picture of the pork production chain is needed that includes management practices aimed at health and welfare of swine and practices within swine operations that affect the environment and community health. Swine practices indirectly influence the spread of zoonotic enteric pathogens. Pathogens in food animals can escape detection, and critical control points often are missed. Preharvest growth of swine by enhancement of normal gut flora and targeting intestinal pathogens through nonantibiotic approaches might improve food safety and reduce antibiotic residues. In light of the threat posed by multidrug-resistant pathogens, old dogma is being revisited with optimism for potential utility in promoting pre- and postharvest pork safety. This review includes possible approaches that can be implemented in swine operations and postslaughter during pork processing with simultaneous omission of subtherapeutic antibiotics to control Salmonella. We emphasize the vital roles of the veterinarians, pig producers, industry, food research scientists, and government guidelines for the strategic implementation of approaches to Salmonella control across the pork production and processing chains.     

Natural-light labeling of tomatoes does not facilitate growth or penetration of Salmonella into the fruit

The survival-growth capacity of Salmonella populations on tomato epidermis labeled by a natural-light labeling system was investigated after persistent fears of such marks serving as possible entryways for the pathogenic organisms, alone and in the presence of Pectobacterium carotovorum subsp. carotovorum, a soft-rot organism. Different treatments involving natural-light labeling, fruit waxing, and a five-strain cocktail of Salmonella were applied to mature green tomato surfaces in different sequences prior to storage at 4, 12, or 25°C. Fruit was sampled every 3 days, and Salmonella was enumerated from all treatments and unlabeled fruit, which served as controls. There were no significant differences between treatments or between treatments and controls throughout. The results indicate that the cuticle and epidermal interruptions caused by natural-light labeling do not facilitate the penetration and colonization of the tomato pericarp. In a separate set of experiments, the capacity of Salmonella to penetrate tomato in the presence of a potential synergism with P. carotovorum subsp. carotovorum was investigated. The addition of P. carotovorum at higher, lower, or equal population densities to Salmonella did not significantly alter the behavior of Salmonella on tomatoes stored at 25°C, regardless of natural-light labeling. The inability of P. carotovorum and Salmonella to colonize natural-light-etched surfaces of tomato fruit indicates that the use of this technology does not adversely compromise the surface of tomatoes.     

Solvent induced crystallization of syndiotactic poly(methyl methacrylate) relation to the formation of polymer aggregates in solution

Polymer Bulletin - Solutions of syndiotactic (s) poly (methyl methacrylate) (PMMA) and samples of solid s-PMMA prepared from these solutions were studied by NMR and infrared (IR) spectroscopy and...     

Relationship between dam's age at bull's birth and bull's genetic evaluation

After accounting for year of birth of bulls, younger dams produced superior sons. Bulls' PD, parent average, and pedigree index milk decreased with increasing age of dams at bull's birth. This appears to be due to decrease in maternal grandsire's PD milk and dam's Cow Index milk with increase in age of dam. Younger dams have an advantage of potentially higher genetic merit due to genetic trend but have less information included in their evaluations. Bull's latest parent average and pedigree index overestimated latest PD milk. This overestimation was not different with age of dam at bull's birth, suggesting that the bias in predicting bulls' PD from eventual evaluations of dams chosen at a younger age is not different than for dams chosen at a later age. Data were for 2826 bulls sampled by four AI organizations and born between 1965 and 1981. The increase in PD milk of bulls was about 27 kg/yr, but the trend was larger (45 kg/yr) during the last 5 yr. Inclusion of dam's age did not improve prediction of bull's PD milk. Maternal grandsire's PD milk was the primary variable associated with dam's age that accounted for lower bull's PD milk, mainly because older dams tended to have sires of lower genetic merit.