Influence of storage, heat treatment, and solids composition on the bleaching of whey with hydrogen peroxide

The residual annatto colorant in liquid whey is bleached to provide a desired neutral color in dried whey ingredients. This study evaluated the influence of starter culture, whey solids and composition, and spray drying on bleaching efficacy. Cheddar cheese whey with annatto was manufactured with starter culture or by addition of lactic acid and rennet. Pasteurized fat-separated whey was ultrafiltered (retentate) and spray dried to 34% whey protein concentrate (WPC34). Aliquots were bleached at 60 °C for 1 h (hydrogen peroxide, 250 ppm), before pasteurization, after pasteurization, after storage at 3 °C and after freezing at -20 °C. Aliquots of retentate were bleached analogously immediately and after storage at 3 or -20 °C. Freshly spray dried WPC34 was rehydrated to 9% (w/w) solids and bleached. In a final experiment, pasteurized fat-separated whey was ultrafiltered and spray dried to WPC34 and WPC80. The WPC34 and WPC80 retentates were diluted to 7 or 9% solids (w/w) and bleached at 50 °C for 1 h. Freshly spray-dried WPC34 and WPC80 were rehydrated to 9 or 12% solids and bleached. Bleaching efficacy was measured by extraction and quantification of norbixin. Each experiment was replicated 3 times. Starter culture, fat separation, or pasteurization did not impact bleaching efficacy (P > 0.05) while cold or frozen storage decreased bleaching efficacy (P < 0.05). Bleaching efficacy of 80% (w/w) protein liquid retentate was higher than liquid whey or 34% (w/w) protein liquid retentate (P < 0.05). Processing steps, particularly holding times and solids composition, influence bleaching efficacy of whey. PRACTICAL APPLICATION: Optimization of whey bleaching conditions is important to reduce the negative effects of bleaching on the flavor of dried whey ingredients. This study established that liquid storage and whey composition are critical processing points that influence bleaching efficacy.     

The effect of nanowire length and diameter on the properties of transparent, conducting nanowire films

This article describes how the dimensions of nanowires affect the transmittance and sheet resistance of a random nanowire network. Silver nanowires with independently controlled lengths and diameters were synthesized with a gram-scale polyol synthesis by controlling the reaction temperature and time. Characterization of films composed of nanowires of different lengths but the same diameter enabled the quantification of the effect of length on the conductance and transmittance of silver nanowire films. Finite-difference time-domain calculations were used to determine the effect of nanowire diameter, overlap, and hole size on the transmittance of a nanowire network. For individual nanowires with diameters greater than 50 nm, increasing diameter increases the electrical conductance to optical extinction ratio, but the opposite is true for nanowires with diameters less than this size. Calculations and experimental data show that for a random network of nanowires, decreasing nanowire diameter increases the number density of nanowires at a given transmittance, leading to improved connectivity and conductivity at high transmittance (>90%). This information will facilitate the design of transparent, conducting nanowire films for flexible displays, organic light emitting diodes and thin-film solar cells.     

The historical geographies of growing and fermenting the Delaware grape in the Kōfu Basin of Yamanashi Prefecture,Japan

The Kōfu Basin in Yamanashi Prefecture is at the center of table grape and wine production in Japan. This article traces the historical geographies of the growing and fermentation of Delaware grapes in this region. Data were gathered from over 145 interviews with stakeholders across the table grape and wine industries, extensive archival research and participant observation as a grape farmer in the Kōfu Basin for over one and a half years. Emphasis is placed on intertwining that history to overarching developments in local viticulture and winemaking. This includes tracing the arrival of the cultivar from the USA to Japan at the start of the Meiji Restoration in 1868, early fermentation and later rapid diffusion linked to its popularity as the first commercially available seedless cultivar. Delaware reached the pinnacle of its popularity as a grape for the table and wine in the 1960s and 1970s, before changes in consumer demands to higher value table grapes and away from sweet wines led to its fairly rapid decline. Although significantly less Delaware is grown or fermented today, this introduced grape was and surprisingly continues to be highly influential on the developmental trajectories of Japanese grape growing and winemaking.     

Device characteristics of a 10.1% hydrazine‐processed Cu2ZnSn(Se,S)4 solar cell

A power conversion efficiency record of 10.1% was achieved for kesterite absorbers, using a Cu₂ZnSn(Se,S)₄ thin‐film solar cell made by hydrazine‐based solution processing. Key device characteristics were compiled, including light/dark J–V, quantum efficiency, temperature dependence of V_oc and series resistance, photoluminescence, and capacitance spectroscopy, providing important insight into how the devices compare with high‐performance Cu(In,Ga)Se₂. The record kesterite device was shown to be primarily limited by interface recombination, minority carrier lifetime, and series resistance. The new level of device performance points to the significant promise of the kesterites as an emerging and commercially interesting thin‐film technology. Copyright © 2011 John Wiley & Sons, Ltd.     

Improving myoelectric pattern recognition robustness to electrode shift by changing interelectrode distance and electrode configuration

Pattern recognition of myoelectric signals for prosthesis control has been extensively studied in research settings and is close to clinical implementation. These systems are capable of intuitively controlling the next generation of dexterous prosthetic hands. However, pattern recognition systems perform poorly in the presence of electrode shift, defined as movement of surface electrodes with respect to the underlying muscles. This paper focused on investigating the optimal interelectrode distance, channel configuration, and electromyography feature sets for myoelectric pattern recognition in the presence of electrode shift. Increasing interelectrode distance from 2 to 4 cm improved pattern recognition system performance in terms of classification error and controllability (p < 0.01). Additionally, for a constant number of channels, an electrode configuration that included electrodes oriented both longitudinally and perpendicularly with respect to muscle fibers improved robustness in the presence of electrode shift (p < 0.05). We investigated the effect of the number of recording channels with and without electrode shift and found that four to six channels were sufficient for pattern recognition control. Finally, we investigated different feature sets for pattern recognition control using a linear discriminant analysis classifier and found that an autoregressive set significantly (p < 0.01) reduced sensitivity to electrode shift compared to a traditional time-domain feature set.     

Validation of immunodetection (ELISA) of ricin using a biological activity assay

Abstract: The suitability of enzyme‐linked immunosorbent assay (ELISA) for residual ricin toxicity determination was investigated in this study. Ricin was thermally treated at 80 to 90 °C for up to 9 min, and its residual concentration was determined by means of a commercial ELISA kit, and its bioactivity (amount of adenine released from DNA) was determined by means of a biological activity assay (BAA). Results showed that inactivation of ricin followed 1st‐order kinetics. The half‐life values for loss of bioactivity at 80, 85, and 90 °C were 1.93, 0.65, and 0.41 min, respectively. Similarly, the half‐life values for reduction in ricin concentration determined by ELISA were 3.06, 0.79, and 0.43 min, respectively. The half‐lives determined by both assays were only significantly different at 80 °C. The Z, Q₁₀, and Arrhenius activation energy values determined by both assays were dissimilar: 11.74 ?C, 7.12 and 50.1 kcal/mol, respectively, by ELISA; and 14.87 °C, 4.71 and 39.5 kcal/mol, respectively, by BAA. Nevertheless, our findings indicate that the 2 assays were highly correlated (R²= 1), and it can be concluded that ELISA would be a reliable method for detecting residual toxicity of heat‐treated ricin based on fraction lost. Practical Application: The results of this study indicate that immunodetection, even though not a direct measurement of the biological activity of ricin, is suitable for determining the residual bioactivity of ricin since immunodetection and the biological activity assay used in this investigation were highly correlated. Therefore, ELISA can be used for routine assessment of residual activity or toxicity of ricin in thermally treated foods.