CALCULATION OF MOLECULAR WEIGHTS AND KJELDAHL NITROGEN-TO-PROTEIN CONVERSION FACTORS FOR MYOFIBRILLAR PROTEINS FROM AMINO ACID SEQUENCES

The objectives of this research were to calculate the molecular weights and Kjeldahl conversion factors for the major myofibrillar proteins from knowledge of their primary structures. Kjeldahl nitrogen-to-protein conversion factors for the myofibrillar proteins myosin, actin, and tropomyosin were calculated from amino acid sequences found in the literature. The molarity of pure protein solutions can be determined without the use of a primary standard with the Kjeldahl nitrogen determination method and use of calculated Kjeldahl nitrogen-to-protein conversion factors. The molecular weights of bovine myosin (519,725), actin (41,549), alpha-tropomyosin (32,680), and beta-tropomyosin (32,811) were calculated. The nitrogen-to-protein conversion factors for these proteins were calculated to be respectively 6.05, 6.29, 6.24, and 6.25. The molecular weights of myosin light chains L1, L2, L3, and L4 and the myosin heavy chain were calculated and their respective nitrogen-to-protein conversion factors were: 6.18, 6.34, 6.34, 6.32, and 6.01.     

Aerobic Microflora of Commercially Harvested, Transported and Cryogenically Processed Col lards (Brassica oleracea)

Samples of spring and fall harvested collards were obtained at critical stages in a normal harvesting, transportation and cryogenic processing operation and microbiologically analyzed for total plate counts, En-terobacreriaceae counts, and yeasts and molds. Operations that involved extended holding times and mechanical handling tended to increase all counts significantly while blanching and blast freezing with liquid N₂ reduced counts to acceptable levels. Differences were significant in all counts by sampling points and dates. Prominant genera of Enterobacteriaceae isolated from the frozen product were those normally associated with soil contamination and not normally considered pathogenic to humans.     

用于免耕深色晾晒烟苗期杂草控制的除草剂使用方式实验

烟草的保护性耕作体系可保存土壤湿度并切实减少因风雨造成的能量消耗和土壤侵蚀。保护性耕作还可以允许烟农在阴雨天气里适时施用田间杀虫剂。由于机械化耕作在保护性耕作方式中不作为除草剂的补充，从而使得在整个生长季的杂草控制变得困难。躲过了早期田间除草剂的阔叶杂草将会成为免耕烟草的难题。因此，2004至2005年间在肯塔基的普林斯顿进行了有关试验，对免耕深色晾晒烟的杂草控制功效及试验性阔叶型杂草除草剂的作物耐受性进行评估。     

Chromatographic Analyses of Xanthophylls in Egg Yolks from Laying Hens Fed Turf Bermudagrass(Cynodon dactylon) Meal

The characterization of xanthophylls in egg yolks from laying hens fed turf bermudagrass (Cynodon dactylon) meal was studied. Laying hens were fed 2 wk on a milo-soybean meal diet to deplete the birds' xanthophyll stores from developing ova prior to introduction of 9% turf bermudagrass. After an additional 4 wk the various carotcnoids present in egg yolks were determined by open-column, thin-layer, and high-performance liquid chromatography. Chromatographic analyses suggest that the yolk color was due mainly to the presence of free lutein and zeaxanthin at a ratio of 4:1. Neoxanthin and violaxanthin were present in minor amounts. The presence of p-carotene was not detected.     

Water-Soluble Flavor and Odor Precursors of Meat. 4. Influence of Cooking on Nucleosides and Bases of Beef Steaks and Roasts and Their Relationship to Flavor, Aroma and Juiciness

SUMMARY: Cooking resulted in significant increases in adenylic acid, total purine nucleosides and bases of 80 beef roasts of eight different cuts. It decreased the contents of inosinic acid, guanylic acid and sum of individual nucleotides (adenylic, cytidylic, uridylic, inosinic and guanylic acids) in these samples. Significant differences were also found between the various constituents of raw and cooked samples of the beef cuts.