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S D Jones

Publications and source records attributed to S D Jones.

62 records · Page 4Linked to original sources
PubMed1984

Changes in the solubility of bovine intramuscular collagen due to nutritional regime.

Longissimus dorsi muscles were removed from the carcasses of 60 Charolais-cross steers in order to examine the relationship between five feeding systems and collagen solubility values obtained by two different methods (warm and cold extractions). Steers were provided with either a 75% concentrate diet, 50% concentrate diet, corn silage diet, corn silage to 400 kg live weight followed by the 75% concentrate diet or alfalfa silage fed to 400 kg live weight followed by the 75% concentrate diet. Steers on the 75% concentrate diet throughout the feeding period required the least time on feed, had the lowest slaughter and carcass weights and produced meat with the highest warm collagen solubility values. Steers fed corn silage continuously needed the longest time on feed, had the lowest daily rates of gain and produced meat with the lowest warm collagen solubility values. Despite being on feed for a longer length of time, steers fed corn silage or alfalfa silage prior to finishing on the 75% concentrate diet produced meat with warm collagen solubility values similar to those continuously fed the 50% concentrate diet. Steers fed the 75% concentrate diet subsequent to forage feeding exhibited greater rates of gain before slaughter while those fed the 75% concentrate diet continuously showed a rapid decline in rate of gain with increasing body weight. Total collagen and cold collagen values were similar among feeding systems. These results indicated that plane of nutrition before slaughter and days on feed both exerted an influence on the properties of intramuscular collagen.

Animal Feed↗
PubMed1980

Effect of sterol side chains on growth and membrane fatty acid composition of Saccharomyces cerevisiae.

Saccharomyces cerevisiae GL7 cells require exogenous sterol and unsaturated fatty acid for growth. When grown in the presence of cholesterol or 7-dehydrocholesterol, the cells incorporated less saturated fatty acid into phospholipids than cells grown with ergosterol, stigmasterol, or beta-sitosterol as the sterol source. This lower saturated fatty acid content was most pronounced in phosphatidylethanolamine, slightly less so in phosphatidylcholine, and least evident in phosphatidylserine and phosphatidylinositol. Growing the cells with the various sterols did not affect the ratios of individual phospholipids. The ability of strain GL7 to use 7-dehydrocholesterol as the only sterol supplement for growth was dependent upon the nature of the unsaturated fatty acids added to the growth medium. In the presence of linoleic, linolenic, or a mixture of palmitoleic and oleic acids, excellent growth was observed with either ergosterol, cholesterol, or 7-dehydrocholesterol. However, when the medium was supplemented with either oleic or petroselenic acid, the cells grew more slowly (oleic) or much more poorly (petroselenic) with 7-dehydrocholesterol than with ergosterol. A specific relationship between sterol structure and membrane fatty acid composition in yeast cells is implied.

Cholestanol↗
PubMedDate not supplied

Evaluation of a commercial process for collection and cooling of beef offals by a temperature function integration technique.

The hygienic adequacy of a commercial process for the collection and cooling of beef offals was assessed by a temperature function integration technique. The diverse operations for collection of offals were inspected. The rates of product movement through those operations, and the temperatures of products at the time of their being packed, were determined. From that information, four of the nine product types were selected for examination of their temperature histories during the assembly and cooling of the cartoned products. The products selected encompassed product at near-body and near-air-ambient temperatures at the time of packaging, product in the largest and smallest cartons used in the process, and product with relatively short and long residence times in an unchilled carton stack assembly area. Twenty-one temperature histories were collected for each of the products, and the possible proliferation of an indicator organism, Escherichia coli, calculated for each temperature history. The results were assessed against a temperature function integration criterion derived from studies of beef carcass and cartoned meat cooling processes. Products packaged at near-ambient temperature readily met with the criterion, but products packed at near-body temperatures did not comply. The latter non-compliance was extreme for product packaged in large cartons. However, the principal cause of non-compliance was identified as highly variable cooling conditions in the carton freezing facility. A brief survey of air speeds and temperatures within that facility indicated means by which product cooling could be better controlled.

Animals↗