Retinyl Palmitate Isomers in Skim Milk During Light Storage as Affected by Ascorbic Acid

Effects of ascorbic acid addition on the contents of retinyl palmitate isomers in skim milk treated with or without 3 mg/mL added riboflavin were studied during storage for 30 h under fluorescent light. Light illumination induced the reduction of all-trans-retinyl palmitate and 13-cis isomer, but promoted the production of 9-cis isomer in the skim milk. Riboflavin increased the reduction of all-trans-retinyl palmitate, but decreased the formation of 9-cis isomer in lightstored skim milk. The addition of ascorbic acid greatly inhibited the light-induced reduction of all-trans-retinyl palmitate and 13-cis isomer in skim milks. Ascorbic acid also greatly increased the formation of 9-cis-retinyl palmitate in skim milks during light storage.     

提高虚拟车削仿真质量的工件建模方法

根据车削加工工件的几何外形和成形特点 ,提出了包含加工误差信息的回转体类工件半剖轮廓多边形建模方法和记录、组织加工误差信息的刀具轨迹法。在虚拟加工中 ,刀具扫描体被简化表示为刀具扫描体轮廓多边形 ,简化了仿真计算。同时还对加工过程仿真和反映加工误差的已加工表面形貌的构建等关键问题进行了研究。该建模方法在VMIS虚拟加工与检测系统中获得了应用     

Microbiological Evaluation of Alaska Shore-based Surimi Production

Two shore-based surimi plants in Alaska were investigated to determine microbial conditions of Alaska pollock flesh during processing. Median aerobic plate count (APC) was 2.0 × 10³/g after mincing, 2.3 × 10³/g after washing/screening, 4.2 × 10⁴/g after refining and 1.6 × 10⁴/g after dewatering. Reprocessing, needed for nonanalog grade surimi, resulted in APC of 1.2 × 10⁵/g after a second refining and 3.0 × 10⁵/g after a second dewatering. The APC for analog grade surimi was 5.5 × 10⁴/g and 2.0 × 10⁶/g for nonanalog grade surimi. Highest total coliform most probable number (MPN) of > 1100/g was determined from a nonanalog grade surimi sample and from a mince that had been refined twice. Highest Escherichia coli MPN of 460/g was determined from two minces.     

Effect of Added Lactobacilli on Composition and Texture of Cheddar Cheese During Accelerated Maturation

The evolution of cheese composition and texture was studied in maturing Cheddar cheese supplemented with live cells and cell homogenates of Lactobacillus casei-casei L2A in order to accelerate maturation. The pH was significantly modified by the lactic acid of the bacterial additives. The Theological properties showed the same general pattern of evolution in experimental as in control cheeses. The process we developed has led to a good-quality matured cheese with 40% increase in flavor intensity compared to control cheeses.     

Al-C-Ni组分的变化对Al-C-Ni与ITO层接触电阻的影响

为克服大尺寸显示面板中反应时间的延迟问题,采用低阻栅线是十分有益的,同样在小尺寸面板上也存在这种相互匹配的过程。然而,由于Al较高的氧化速度,铝合金和ITO材料接触性能并不太好。文章介绍了在室温ITO沉积过程中,通过增加ACX(Al-C-Ni)中Ni含量来减少ACX-ITO接触电阻。经室温ITO沉积后,接触电阻成功地减少到300Ω,而且没有ACX引起的问题出现。     

Identifying Nucleotidic Materials Released by Fermenting Brewer's Yeast

SUMMARY— During fermentation a brewer's yeast released into the medium substantial amounts of materials absorbing ultra-violet light at 260 mμ These materials were separated by chromatography and identified by further chromatography and spectrophotometry. Nine nucleotides, five free bases (purines and pyrimidines) and four nucleosides were identified in the fermented medium and in the intracellular pool of the yeast. Some of these released materials may be of consequence in the fermented beverage industry since they were not reabsorbed by yeast and can be expected to persist to the finished product.     

Chemical Induction of Mutation or Variation In Aflatoxin-Producing Cultures of Aspergillus Flavus

SUMMARY– The mutation or variation of a strain of Aspergillus flavus was induced chemically after six successive "generations" of exposures to barium ions. Colony isolates of A. flavus , developing from spores harvested from cultures grown in barium medium, were examined for mutation on the basis of morphology, loss of aflatoxin-producing capacity, and loss of ability to grow in basal medium. The new characteristics exhibited by the mutant of A. flavus are the inability to produce aflatoxins and yellow pigment, accompanied by the loss of fluorescence in the culture under ultraviolet light. These changes did not revert after more than eight successive transfers in a barium-free medium. Mutagenic action of barium ions on the fungus A. flavus was shown by the mutatation of colonies arising from single spores, The characteristics of the mutant are permanent and irreversible.     

Effect of Chlorophenoxyacetic Acid Growth-Regulator Sprays on Residues in Canned Apricots and Grapes

SUMMARY— A, gas-liquid chromatographic method coupled with an electron capture detector has been developed for analyzing chlorinated phenoxyacetic acid residues in canned fruits. The technique involves converting the acid to its methyl ester with diazomethane, chromatography on a 5% silicone grease SE-30 column at 210°C, and subsequent detection of the compound by an electron capture detector. As low as 0.02 ppm of the residue could be detected. The method is superior to the calorimetric method because parachlorophenoxyacetic acid (PCPA), 2,4-D, and 2,4,5-T can be separated and quantitatively determined simultaneously. However, separate standard curves are needed for each, because they differ in chlorine content and in sensitivity toward the electron capture detector. Levels of 2,4-D and 2,4,5-T residues in canned apricots, and of PCPA in canned grapes are reported.