EFFECT OF MICROBIAL GROWTH UPON MYOFIBRILLAR PROTEINS

SUMMARY— Aseptic samples from pig and rabbit muscles were inoculated with Achromobacter liquefaciens, Micrococcus luteus, Pediococcus cerevisiae, Pseudomonas fluorescens, Streptococcus faecal is end a mixed culture obtained from commercial hamburger. Some difficulty was encountered in getting the organisms to grow, and good growth was achieved only with A. liquefaciens end mixed culture from commercial meat. Both inoculated and uninoculated control samples were incubated at 3 and 10°C for 0, 8 and 20 days. The salt soluble proteins were extracted with Weber-Edsall solution and subjected to sucrose density gradient centrifugation, gel filtration and disc gel electrophoresis. The microorganisms utilized in this study had no measurable effect upon the myofibrillar proteins from either pig or rabbit muscle. However, bacterial growth decreased the amount of certain non-protein ultra-violet absorbing components in the ultracentrifugal pattern of Weber-Edsall extract. These components did not appear to be of myofibrillar origin. Disc gel patterns of Weber-Edsall extracts from pig muscle produced a more intensely staining band than those from rabbit muscle at R_m, = 0.59.     

Effect of Modified Atmosphere Blending on the Oxidative Stability and Color of Frozen Mechanically Separated Poultry Meat

The effect of blending mechanically separated poultry meat under several modified atmospheres was investigated. Treatments included vacuum, nitrogen, nitrogen containing carbon monoxide (I%, 5% and 10%) and an unblended control. The blended and control meats were sealed in gas impermeable plastic pouches and stored at ?10°C for 7 months. Oxidative stability was evaluated at monthly intervals by monitoring the appearance of malonaldehyde using HPLC. Surface color determined with a HunterLab color difference meter was also used as a critereon of frozen storage quality. The modified atmosphere treated meats were found to be more stable than the control (P < 0.05). Meats blended with atmospheres containing CO were redder (P < 0.01) than the control, vacuum or nitrogen blended samples.     

Limonoid Debittering of Citrus Juice Sera By Immobilized Cells of Corynebacterium fascians

Corynebacterium fascians cells capable of metabolizing limonoids were prepared conveniently with inexpensive carbon sources such as fructose, galactose and citric acid. Cells thus obtained were immo-bilized in acrylamide gel and used in a biological debittering process previously developed. The process significantly reduced limonin and nomilin contents of citrus juice sera. It was particularly effective toward the reduction of nomilin. The debittering treatment did not have adverse effects on the composition of other citrus constituents such as citric, malic, ascorbic acids, fructose, glucose and sucrose.     

Limonoid Glucosides in Fruit, Juice and Processing by-products of Satsuma Mandarin (Chus unshiu Marcov.)

In a study on improving utilization of waste from processing of Satsuma mandarin (Citrus unshiu Marcov.) the limonoid glucosides of fruit, juice, and by-products were measured using HPLC and TLC. All materials had the 17-β-D-glucopyranoside derivatives of limonoids reported in other commercial citrus fruit. Citrus molasses was a good source for industrial scale extraction of limonoid glucosides. An extraction system using polystyrene divinylbenzene resins, was developed which could be expanded to industrial scale.     

n-Hexanol Formation from n-Hexanal by Enzyme Action in Soybean Extracts

n-Hexanal in soybean homogenates decreased during incubation at alkaline pH. When soybean extracts were dialyzed and then incubated with n-hexanal and cofactors [nicotinamide adenine dinucleotide (NAD⁺), the reduced form (NADH), nicotinamide adenine dinucleotide phosphate (NADP+), and the reduced form (NADPH)], NADH and NADPH stimulated the enzymatic reduction of n-hexanal with NADH being more effective than NADPH. When undialyzed preparations were incubated, all the cofactors stimulated enzymatic activity, with NADH being the most effective. The reaction product in all the incubation mixtures was n-hexanol; n-hexanal was reduced to n-hexanol stoichiometrically. It was suggested that alcohol dehydrogenase was responsible for the decrease of n-hexanal in soybean homogenate at alkaline pH.     

Introduction of High Pressure to Food Processing: Preferential Proteolysis of β-Lactoglobulin in Milk Whey

Various proteins were subjected to thermolysin digestion at 2000 atm. Casein and soy protein were extensively digested at both atmospheric and high pressures, but the tetrameric proteins alcohol dehydrogenase and hemoglobin and the monomeric protein β-lactoglobulin were degraded only upon pressurization. Globular proteins with many disulfide bonds (RNase A, lysozyme, and α-lactalbumin) resisted the proteolysis at both pressures. These observations led to the preferential digestion of β-lactoglobulin in cow's milk whey, thus simulating human milk protein. The versatility of pressure-induced proteolysis in food processing is also proposed.     

Mechanical Properties on Ni3 Al Intermetallic Compound-SiC Composite Material Generated by SHS Method

0 Introduction The Ni3 Al intermetallic compound is of great interest because of its corrosion-resistance, and high melting point. However, it is difficult to make the intermetallic compound using the ordinary method.     

Electron Paramagnetic Resonance in R2O-Al2O3−SiO2 Glass Systems

Systematic detection of an EPR signal was conducted for three alkali oxide-Al₂O₃−SiO₂ glass systems. Observed EPR spectra, having a main line with g=2.03 and a broad and anisotropic shape, are attributed to the unsaturated bridging oxygen bond resulting from the breakup of the SiO₂ random network. This signal appears in the area AValkali atom ratio >1 for the Na₂0 and K₂O systems, indicating that the collapse of the Al 4-coordinated structure begins at an equimolar ratio when alumina is substituted for the alkali oxide, whereas somewhat different behavior was observed for the Li₂O system.     

北京养老服务机构建设布局及使用状况的初探——关于合理布局建设养老服务机构

随着北京市老龄率的不断增加,市政府通过增建养老服务机构、推行居家养老政策等措施努力改善提高养老服务水平。本文从城市规划的角度着眼于养老服务机构的建设布局,通过分析其建设布局与使用状况(床位使用率)的关系,探讨建设现状的合理性,并提出相关改善方案。     

EXTRACTION OF PALLADIUM(II) AND PLATINUM(IV) AS CHLOROCOMPLEX ACIDS INTO BASIC ORGANIC SOLVENTS

Solvent extraction of platinum(IV) and palladium(II) with tri-n-octylamine(TOA) in o-xylene from 4.0M (Na,H)(Cl, HSO₄) has been investigated at 298K in order to compare with similar extraction by trioctylphosphine oxide(TOPO). The dependence of the distribution ratio of platinum(IV) and pal 1adium(II) on TOA, hydrogen ion and chloride ion concentrations suggests the dominant extracted species of these metals would be 2:1 for proto-nated amine : chlorocomplex anion and the extraction should be essentially anion exchange reaction. The extraction constants (Kex = D[H⁺(T0A)C1 ] ²[C1 ]²), were evaluated as 10^6-3 and 10^5.8 for platinum(IV) and pal ladium(II), respectively. The anion exchange with protonated TOPO salt represented by H(T0P0)₂ ⁺C1  is less than that with protonated TOA salt by a factor of one order.