Pink yeasts identified as Rhodotorula glutinis var. glutinis, R. minuta var. minuta, and R. rubra produce polygalacturonases which cause a slow softening of olive tissue. Both pectin methyl esterase and polygalacturonase are produced when cultures are grown in appropriate media. Crude, cell-free dialyzed enzyme preparations measured viscosimetrically exhibited optimal activity on sodium polygalacturonate at pH 6.0 and 40 C, and were active in the range of pH 4.0 to 9.0 and 10 to 50 C. Cultures grown in sterilized olives and brine atpH 4.0 with sterile glucose added aseptically caused a slow softening of tissue as measured with a Christel texturometer. Similar results were obtained when crude, cell-free enzyme preparations were added to olives in buffer solution at pH 6.0 with Merthiolate. Commercial control of these yeasts is easy if anaerobic conditions can be provided. Otherwise, the industry has to resort to manual removal of the film from the brine surface, either by skimming or by flagellation.

No abstract

Effect of soy flour, soy protein concentrate, and isolate on dough and loaf properties of breads produced from flour, yeast, salt, and water with no shortening or added improvers was investigated. Wheat flour, rye flour, and mixtures of the two were included in the studies. Three wheat flours, varying in baking quality and extraction, ash content 0.65 and 0.80%, were used; 1.5, 3, and 5% soy products, flour basis, were added. Water absorption increased 3.8-4.7% at the 3% soy level and 6.1-7.3% at the 5% levet of soy product addition. Dough development time and stability were increased and dough softening reduced. Dough gassing power increased ca. 7-25%. By using a shorter proofing time, more intensive mixing, and the sponge dough process, loaves only slightly smaller in volume than the control were obtained at the 3% soy level. Panel evaluations scored bread highest with 1.5 or 3% soy flour and that with 3 or 5% soy protein concentrate as lowest, but acceptable. Use of 2% lard as shortening, or 2% lard plus emulsifier, produced soy breads of excellent quality and ca. 25% higher loaf volume than controls.

Pink yeasts identified as Rhodotorula glutinis var. glutinis, R. minuta var. minuta , and R. rubra produce polygalacturonases which cause a slow softening of olive tissue. Both pectin methyl esterase and polygalacturonase are produced when cultures are grown in appropriate media. Crude, cell-free dialyzed enzyme preparations measured viscosimetrically exhibited optimal activity on sodium polygalacturonate at p H 6.0 and 40 C, and were active in the range of p H 4.0 to 9.0 and 10 to 50 C. Cultures grown in sterilized olives and brine at p H 4.0 with sterile glucose added aseptically caused a slow softening of tissue as measured with a Christel texturometer. Similar results were obtained when crude, cell-free enzyme preparations were added to olives in buffer solution at p H 6.0 with Merthiolate. Commercial control of these yeasts is easy if anaerobic conditions can be provided. Otherwise, the industry has to resort to manual removal of the film from the brine surface, either by skimming or by flagellation.

No abstract