Emulsifying properties of pea protein/guar gum conjugates and mayonnaise application

Modified plant protein may be used as a healthy and more functional emulsifier in food products. The objective of this study was to evaluate the emulsifying properties of functionally enhanced pea protein (i.e. pea protein conjugated with guar gum, G-PPI) and its potential application to mayonnaise, compared with unmodified pea protein. Emulsions containing G-PPI were prepared at different pH, salt concentrations, protein concentrations and oil/water ratios. Mayonnaise samples were prepared using the pea proteins or egg yolk powder. Various characteristics of the emulsions, including droplet size, apparent viscosity, viscoelasticity and microstructure, were analysed. The emulsions with G-PPI had significantly increased stability of up to 89.4% and apparent viscosity of up to 48.62 mPa.s. The G-PPI emulsion had a smaller average droplet size of 934.4 nm at pH 7 compared with the PPI emulsion (stability 62.7%, apparent viscosity 22.8 mPa.s and droplet size 1664.8 nm). The pH, NaCl concentration, protein concentration and oil/water ratio greatly affected the emulsifying properties. The G-PPI mayonnaise at higher protein concentrations (6 or 8%) exhibited excellent emulsifying and rheological properties. The modified pea protein through the green modification process with natural polysaccharides could be used as a safe and functional emulsifier in different emulsified foods.     

Catalytic pyrolysis of cellulose with oxides: effects on physical properties and reaction pathways

Clean Technologies and Environmental Policy - Fast pyrolysis is a potential technology for converting lignocellulosic biomass into bio-oil, a potential substitute for crude oil and a source of...     

Improved dynamic properties of thermoplastic polyurethanes made from co-monomeric polyester polyol soft segments based on azelaic acid

Research and developmental work of bio-based materials from both renewable resources and biotechnological processes have gained significant interest recently. In this study, bio-based azelaic acid has been used in combination with succinic and adipic acids to synthesize co-monomeric polyester polyol soft segments for thermoplastic polyurethanes (TPUs). Hysteresis of TPUs made from co-monomeric polyester polyols were significantly lower in comparison to the reference TPUs made from monomeric polyester polyols, indicating significant improvement in dynamic properties. In addition, tensile sets of TPUs prepared with co-monomeric polyester polyols were lower compared to TPUs prepared from monomeric polyester polyols, confirming excellent dynamic properties. Improved dynamic properties of TPUs based on co-monomeric polyester polyols can be ascribed to a phase-separated morphology which was quantified as the lowest fraction of bonded urethane from FTIR spectra, reduced crystallinity in differential scanning calorimetry thermograms, narrow tan δ peaks measured using dynamic mechanical analyses, and images from atomic force microscopy.     

Improving CNC contouring accuracy by integral sliding mode control

In this paper, an integral sliding mode controller (ISMC), based on input–output models, is proposed as a refinement from a two-degree-of-freedom controller with independent objectives for tracking and regulation. Thus, the knowledge of pole placement can be utilized in ISMC. The robustness is improved by a disturbance estimation, which results in an equivalent control. To eliminate the problem of chattering, two measures adopted are an appropriate choice of the sliding surface and an integral control action. It was found that the choice of a slower natural frequency of the sliding surface dynamics than that of the open loop can ease the problem of chattering. The choice of k_i, the integral control coefficient, is based on the two-degree-of-freedom controller. Root locus is used in assisting in choosing an appropriate value of k_i to ensure the closed-loop stability. The proposed ISMC was implemented and experimentally tested in a mini-CNC machine. The contouring accuracy of the mini-CNC machine was greatly improved by the proposed ISMC. Furthermore, no chattering was observed, which is beneficial to machine actuators.     

A hybrid cycle bandwidth allocation scheme with differentiated services support in Ethernet passive optical networks

The Ethernet passive optical network (EPON) has emerged as one of the most promising solutions for next generation broadband access networks. Designing an efficient upstream bandwidth allocation scheme with differentiated services (DiffServ) support is a crucial issue for the successful deployment of EPON, carrying heterogeneous traffic with diverse quality of service (QoS) requirements. In this article, we propose a new hybrid cycle scheme (HCS) for bandwidth allocation with DiffServ support. In this scheme, the high-priority traffic is transmitted in fixed timeslots at fixed positions in a cycle while the medium- and low-priority traffic are transmitted in variable timeslots in an adaptive dynamic cycle. A suitable local buffer management scheme is also proposed to facilitate QoS implementation. We develop a novel feature providing potentially multiple transmission opportunities (M-opportunities) per-cycle for high-priority traffic. This feature is significant in improving delay and delay-variation performance. The HCS provides guaranteed services in a short-cycle scale for delay and jitter sensitive traffic while offering guaranteed throughput in a moderately long-time scale for bandwidth sensitive traffic and at the same time maximizing throughput for non-QoS demanding best-effort traffic. We develop analytical performance analysis on the deterministic delay bound for high-priority traffic and minimum throughput guarantees for both high- and medium-priority traffic. On the other hand, we also conduct detailed simulation experiments. The results show a close agreement between analytical approach and simulation. In addition, the simulation results show that the HCS scheme is able to provide excellent performance in terms of average delay, delay-variation, and throughput as compared with previous approaches.

Influence of protein content and storage temperature on the particle morphology and flowability characteristics of milk protein concentrate powders

Milk protein concentrate (MPC) powders are widely used as ingredients for food product formulations due to their nutritional profile and sensory attributes. Processing parameters, storage conditions, and composition influences the flow properties of MPC powders. This study investigated the bulk and shear flow properties of 70.3, 81.5, and 88.1% (wt/wt, protein content) MPC after storage for 12 wk at 25 and 40°C. Additionally, the morphological and functional changes of the MPC powders were investigated and correlated with flowability. After 12 wk of storage at 25°C, the basic flow energy values significantly increased from 510 to 930 mJ as the protein content increased from 70 to 90% (wt/wt). Flow rate index was significantly higher for samples with high protein content. Dynamic flow tests indicated that MPC powders with high protein content displayed higher permeability. Shear tests confirmed that the samples stored at 25°C were more flowable than samples stored at 40°C. Likewise, the higher-protein content samples showed poor shear flow behavior. The results indicated that MPC powders stored at 25°C had less cohesiveness and better flow characteristics than MPC powders stored at 40°C. Overall, the MPC powders had markedly different flow properties due to their difference in composition and morphology. This study delivers insights on the particle morphology and flow behavior of MPC powders.     

Modeling of the XOM/XMP application programming interface (API)

With the growing complexity of communication protocols, it is increasingly difficult for application developers to interface the applications to the communication stacks across a number of platforms. A common application program interface (API) is needed for the purpose. The API can effectively conceal the complexities of communication protocols and architecture, making it easier for application development. This article presents the modeling and development of a generic API, XOM and an application-specific API, XMP. XOM API provides a general-purpose data handling mechanism and XMP API provides service primitives to network management protocols. The development is based on object-oriented technology. The attractiveness of object-oriented implementation is its ability to provide encapsulation, reusability and extensibility in the software modules. The benefits and difficulties encountered during the implementation are to be discussed. The experience will be useful for API development     

External carbon feeding strategy for enhancing nitrogen removal in SBR.

Effective method for feeding an external carbon source (ECS) in SBR was investigated to enhance denitrification based on modifying the anoxic/aerobic sub-cycle for swine wastewater treatment. The wastewater discharged from the scraper-type barns contains relatively low readily biodegradable organic. Therefore NOx-N was accumulated during repeating sub-cycle in SBR operation. When acetic acid was fed as ECS during the final sub-cycle, the maximum nitrogen removal rate was 0.22 kg N/m3/d. This was due to both less denitrification rate during the sub-cycle period and inhibition of denitrification by pH drop during the final cycle. The pH drop was caused by a large amount of ECS feeding to remove high concentration of NOx-N in the final period. To overcome these limitations and achieve higher nitrogen removal rate, the intermittent ECS feeding method with raw wastewater at every anoxic period was developed. Using the modifying ECS feeding method, the removal rate was increased to 0.45 kg N/m3/d without NOx-N accumulation.     

Expression of synapsin I correlates with maturation of the neuromuscular synapse

Synapsins are a family of neuron-specific phosphoproteins that are localized within the presynaptic terminals in adult brain. Previous work has demonstrated that introduction of exogenous synapsins I(a + b) or IIa into Xenopus spinal neurons promoted maturation of the neuromuscular synapse in a nerve-muscle co-culture system. We have now studied the expression of endogenous Xenopus synapsin I during synaptic maturation in vivo and in culture, using a polyclonal antibody raised against Xenopus synapsin I. Immunoprecipitation experiments indicated that synapsin I was not detectable during the early phase of synaptogenesis in vivo, and exhibited a marked increase during the period of synaptic maturation. In contrast, the expression of synaptophysin, another synaptic vesicle protein, was detected at the start of nervous system formation, and remained at a high level thereafter. Similar expression profiles for the two proteins were also observed in immunocytochemical studies of Xenopus spinal neurons in culture: intense staining of synaptophysin was found on the first day, while synapsin I was not detected until after three days in culture. The expression of synapsin I correlated very well with the appearance of a bell-shaped amplitude distribution of spontaneous synaptic currents, a physiological parameter which reflects functional maturation of the neuromuscular synapse. In one-day-old cultures grown in the absence of laminin, an extracellular matrix protein known to be present at the neuromuscular junction, the amplitude distribution of virtually all synapses was skewed towards smaller values. In contrast, when laminin was used as a culture substrate, many synapses exhibited a bell-shaped amplitude distribution. Laminin treatment also induced synapsin I expression in one-day-old cultures. These results suggest that the expression of endogenous synapsin I may regulate maturation at neuromuscular synapses.