Ascorbic Acid Stimulation of Diacetyl Production in Mixed-Strain Lactic Acid Cultures

1979 ◽  
Vol 42 (4) ◽  
pp. 294-296 ◽  
Author(s):  
R. L. RICHTER ◽  
W. S. BRANK ◽  
C. W. DILL ◽  
C. A. WATTS
Keyword(s):  
Ascorbic Acid ◽  
Lactic Acid ◽  
Acid Production ◽  
Sodium Citrate ◽  
Total Solids ◽  
Dry Milk ◽  
Nonfat Dry Milk ◽  
Stimulation Of

The effect of three levels of ascorbic acid on diacetyl and acid production by two mixed-strain cultures was investigated. Each culture was grown in nonfat dry milk reconstituted to 11% total solids with 0.1% added sodium citrate. Ascorbic acid concentrations in the milk were 0, 0.10, and 0.25%. Stimulation of diacetyl production was observed at both concentrations of ascorbic acid. The stimulatory effect of ascorbic acid at both concentrations was approximately the same for each culture. Diacetyl production was initiated earlier in samples containing ascorbic acid. Ascorbic acid did not stimulate acid production.

Stimulation of Lactic Acid Production in Vitro from Prepubertal Rat Ovaries by Gonadotropins and Their Subunits1

Endocrinology ◽  
1973 ◽  
Vol 92 (4) ◽  
pp. 1022-1027 ◽  
Author(s):  
SUSAN WALKER FARMER ◽  
M. R. SAIRAM ◽  
HAROLD PAPKOFF
Keyword(s):  
Lactic Acid ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Stimulation Of

Stabilization of Ascorbic Acid and Its Measurement by Liquid Chromatography in Nonfat Dry Milk

1987 ◽  
Vol 70 (5) ◽  
pp. 806-809
Author(s):  
Sam A Margolis ◽  
Iona Black
Keyword(s):  
Ascorbic Acid ◽  
Liquid Chromatography ◽  
Acid Content ◽  
Ascorbic Acid Content ◽  
Single Step ◽  
Independent Study ◽  
Dry Milk ◽  
Deaerated Solution ◽  
Chromatographic Procedure ◽  
Nonfat Dry Milk

Abstract The determination of ascorbic acid by liquid chromatography (LC) was improved by performing the analysis in the presence of solvents that had been purged with argon to reduce the concentration of oxygen. This methodological modification eliminated the oxidation of ascorbic acid during the chromatographic procedure and reduced the minimum detection level to 1 μg. Solutions of ascorbic acid have been successfully stabilized for 67 days by addition of dithiothreitol to a deaerated solution of water-acetonitrile (25 + 75 v/v), sealed under argon in amber vials and stored at -20°C. In a second independent study, a procedure for the extraction of ascorbic acid from nonfat dry milk in a single step was developed. The ascorbic acid content of Nonfat Dry Milk (SRM 1549) was determined by LC, using the method of standard additions. The mean ascorbic acid content was 54 ± 5 μg/g of sample. Analysis of variance of the analytical results indicates that there is a significant continual increase in the content of the ascorbic acid in each bottle from first to last sample

Composition of Grade A and Manufacturing Grade Herd Milks in South Dakota

1988 ◽  
Vol 51 (9) ◽  
pp. 696-699 ◽  
Author(s):  
ROBERT J. BAER ◽  
JOEL L. SOMMERFELDT ◽  
KAREN M. TIESZEN
Keyword(s):  
South Dakota ◽  
Dairy Products ◽  
Ice Cream ◽  
Milk Composition ◽  
Total Solids ◽  
Milk Samples ◽  
Dry Milk ◽  
Nonfat Dry Milk ◽  
Herd Milk

Biweekly Grade A and manufacturing grade herd milk samples were collected from April 1, 1985, to March 31, 1986, from 203 herds in the Sioux Falls, SD, area and were analyzed to compare composition. The average herd milk composition was 3.70% fat, 3.24% protein, 4.80% lactose, 0.63% ash, 8.67% solids-not-fat (SNF), and 12.37% total solids (TS). Grade A milk had higher % lactose (4.83 and 4.76), % SNF (8.70 and 8.61), and % TS (12.41 and 12.30) than manufacturing grade milk. These compositional differences between grades were consistent throughout the year. Grade A milk has more value in the production of dried dairy products (nonfat dry milk and whey powders) and ice cream than manufacturing grade milk due to its higher lactose and SNF content. New milk pricing plans for protein and other constituents should consider compositional differences (lactose, SNF and TS) that exist between grade A and manufacturing grade herd milk before implementing them.

EFFECT OF MALATHION AND TRICHLORFON ON GROWTH1 AND MORPHOLOGY OF LACTIC CULTURE ORGANISMS

1971 ◽  
Vol 34 (1) ◽  
pp. 16-22 ◽  
Author(s):  
D. D. Deane ◽  
M. M. Van Patten
Keyword(s):  
Lactic Acid ◽  
Cell Size ◽  
Acid Production ◽  
Cell Structure ◽  
Lactic Acid Production ◽  
Lactobacillus Bulgaricus ◽  
Chain Formation ◽  
Streptococcus Lactis ◽  
Litmus Milk ◽  
Dry Milk

Addition of 100 ppm of malathion or trichlorfon had little effect on lactic acid production in reconstituted non-fat dry milk by Streptococus diacetilactis or Streptococus thermophilus. Variation in cell size of Streptococus cremoris 3, Streptococcus lactis W 8 and several strains of S. thermophilus occurred following repeated transfers in litmus milk to which 100 ppm of malathion or 500 ppm trichlorfon had been added. The Lactobacillus bulgaricus A culture, after 15 serial transfers in litmus milk containing 500 ppm of trichlorfon, exhibited increased frequency of chain formation and cell structure 30 to 50 μ long with few visible cross walls. A similar effect was observed with L. bulgaricus A and L. bulgaricus GA after repeated transfers in litmus milk which contained 100 ppm malathion. One of five strains of L. casei studied showed similar changes in morphology after repeated transfers in litmus milk which contained 100 ppm malathion. Adding 500 ppm trichlorfon produced a lesser effect. Changes in morphology of this strain of L. casei were not permanent since cells resumed their usual appearance following three to five transfers in plain litmus milk.

Effect of cadmium on the growth of Lactobacillus lactis, L. helveticus and Streptococcus thermophilus in milk

1984 ◽  
Vol 51 (4) ◽  
pp. 591-596 ◽  
Author(s):  
Hannu Korkeala ◽  
Stefan Soback ◽  
Jorma Hirn
Keyword(s):  
Lactic Acid ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Skim Milk ◽  
Streptococcus Thermophilus ◽  
Inhibitory Effect ◽  
Inhibition Of Growth ◽  
Lactobacillus Lactis ◽  
Stimulation Of ◽  
Slight Inhibition

SummaryThe viable counts, pH and production of lactic acid were determined for Lactobacillus lactis, L. helveticus and Streptococcus thermophilus after 0, 5 and 24 h anaerobic incubation at 44 °C in skim milk containing 0, 3, 5 or 7μg cadmium (Cd)/l. In skim milk containing 7μg Cd/l, a noticeable decrease in lactic acid production and inhibition of the decrease in pH was observed for all three strains after 24 h, although there was only a slight inhibition of growth. With 3 and 5μg Cd/l, there was only a slight inhibition in the decrease in pH. In addition, with 3 μg Cd/l some evidence of stimulation of lactic acid production was found. The inhibitory effect of low Cd concentrations on lactic acid bacteria may give rise to problems in the dairy industry.

THE EFFECT OF INSULIN ON THE UPTAKE OF MONOSACCHARIDES BY THE RAT LENS

1961 ◽  
Vol 22 (4) ◽  
pp. 361-369 ◽  
Author(s):  
RUTH LEVARI ◽  
W. KORNBLUETH ◽  
E. WERTHEIMER
Keyword(s):  
Lactic Acid ◽  
Glucose Uptake ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Bicarbonate Buffer ◽  
Total Uptake ◽  
Order Of Magnitude ◽  
Normal Rat ◽  
Stimulation Of

SUMMARY 1. A direct stimulatory effect of insulin, in vitro, on the uptake of galactose, glucosamine and some pentoses by the intact lens, has been established. Stimulation of glucose uptake is perceptible only under certain conditions, and was more pronounced in a medium of bicarbonate buffer than in phosphate. 2. Insulin increased lactic acid production from glucose and from galactose. 3. Chronic diabetes decreased galactose uptake. Insulin, in vitro, restored the uptake to the level of that of normal rat lenses. 4. Phloridzin was found to cancel the effect of insulin. 5. The increase in uptake by insulin was of the same order of magnitude for glucose and galactose, irrespective of the total uptake. The decrease in uptake due to diabetes was quantitatively the same as the increase by insulin in normal rat lenses. The effect of insulin on lactic acid production was identical for both hexoses. 6. The possible existence of two pathways of glucose uptake in the rat lens is discussed.

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