The effect of lipolytic Gram-negative psychrotrophs in stored milk on the development of rancidity in Cheddar cheese

1976 ◽  
Vol 43 (3) ◽  
pp. 459-468 ◽  
Author(s):  
B. A. Law ◽  
M. Elisabeth Sharpe ◽  
Helen R. Chapman
Keyword(s):  
Heat Treatment ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Pseudomonas Fluorescens ◽  
Culture Supernatant ◽  
Lipolytic Activity ◽  
Cheddar Cheese ◽  
Single Strain ◽  
Gram Negative ◽  
Colony Forming Units

SummaryThe highest incidence of lipolytic activity among the psychrotrophic Gram-negative flora of commercial raw milks was found in strains ofPseudomonas fluorescensandPs. fragi.The lipases of all of the lipolytic strains remained wholly or partly active after heat treatment at 63°C for 30 min. Two of the strains tested further had lipases which retained 20–25% of their activity even when heated at 100 °C for 10 min. Cheeses made from milks in which strains or a single strain of lipolytic Gram-negative rods (GNR) had been allowed to multiply to > 107colony forming units/ml became rancid after 4 months even though the GNR had been killed by pasteurization. The rancidity was characterized by a soapy off-flavour in cheeses containing free fatty acid concentrations from 3 to 10 times higher than those in control cheeses made from stored milks with low counts of GNR. Strong rancidity could be reproduced by adding the culture supernatant of a pre-grown lipolytic strain, but not the washed cells, to milk and pasteurizing it immediately before cheese-making, demonstrating the extracellular nature of the rancidity-inducing lipases.

Influence of hypothyroidism on the lipolytic activity of norepinephrine in the newborn lamb

1986 ◽  
Vol 108 (3) ◽  
pp. 451-454 ◽  
Author(s):  
C. Wrutniak ◽  
G. Cabello
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Thyroid Hormones ◽  
Lipolytic Activity ◽  
Plasma Free Fatty Acid ◽  
Newborn Lamb ◽  
Group A ◽  
Group B ◽  
Infusion Of Norepinephrine ◽  
Medium Group

ABSTRACT The effects of hypothyroidism on the lipolytic activity of norepinephrine were assessed in the newborn lamb. Lambs were separated into three groups: group A were controls; groups B and C were made hypothyroid by administration of benzylthiouracil from birth until 11 days of age. In control lambs, plasma free fatty acid concentrations, used as an index of lipolytic activity, increased significantly (plus 0·45 mmol/l) during the infusion of norepinephrine, whereas they did not change in hypothyroid lambs (group B). Adding thyroxine and tri-iodothyronine to the infusion medium (group C) immediately restored the free fatty acid response to norepinephrine in hypothyroid lambs (plus 0·41 mmol/l). These results suggest that thyroid hormones could modulate the lipolytic activity of catecholamines in the newborn lamb without a latent period. J. Endocr. (1986) 108, 451–454

Role of Enterococci in Cheddar Cheese: Free Fatty Acid Appearance and Citric Acid Utilization1

1975 ◽  
Vol 38 (2) ◽  
pp. 78-83 ◽  
Author(s):  
JANEP. JENSEN ◽  
G. W. REINBOLD ◽  
C. J. WASHAM ◽  
E. R. VEDAMUTHU
Keyword(s):  
Fatty Acid ◽  
Citric Acid ◽  
Free Fatty Acid ◽  
Fatty Acid Content ◽  
Cheddar Cheese ◽  
Gas Production ◽  
Lower Content ◽  
Biochemical Effects ◽  
Neutral Compounds

Eight lots of Cheddar cheese were manufactured to determine the microbiological response and biochemical effects of two strains each of Streptococcus faecalis and Streptococcus durans used as supplemental starters in combination with a commercial lactic culture. Each lot consisted of a control vat of cheese manufactured with the lactic starter only and an experimental vat of cheese containing the lactic starter and one of the enterococcus strains. Combinations of two curing temperatures (7.2 and 12.8 C) and two early cooling treatments (air vs. brine cooling) were used for cheeses from each vat to determine environmental effects on the cheeses. Cheeses manufactured with S. faecalis had a somewhat lower content of free fatty acids than did control cheeses, possibly because of early conversion of acids to neutral compounds. Cheeses manufactured with S. durans showed a fluctuating, but consistent, free fatty acid content among treatments, with overall amounts being greater than in the control cheeses or in cheeses made with S. faecalis. Cheeses cured at 12.8 C showed greater free fatty acid liberation, but the effects of early cooling rates were not significant. Citric acid in cheeses made with S. faecalis and in control cheeses was utilized most rapidly in 30 days at 12.8 C and extending to 60 days when cured at 7.2 C, after which no more breakdown seemed to occur. Cheeses made with S. durans 9–20 followed approximately the same pattern although some utilization took place between 90 and 180 days. In cheeses made with S. durans 15–20, however, citric acid utilization was continuous up to 180 days, and in cheeses cured at 12.8 C, citric acid was nearly depleted at 180 days. Cheeses made with S. durans 15–20 and cured at 12.8 C exhibited excessive gas production.

Role of Enterococci in Cheddar Cheese: Organoleptic Considerations1

1975 ◽  
Vol 38 (3) ◽  
pp. 142-145 ◽  
Author(s):  
JANE P. JENSEN ◽  
G. W. REINBOLD ◽  
C. J. WASHAM ◽  
E. R. VEDAMUTBU
Keyword(s):  
Lactic Acid ◽  
Fatty Acid ◽  
Citric Acid ◽  
Free Fatty Acid ◽  
Cheddar Cheese ◽  
Streptococcus Faecalis ◽  
Growth And Survival ◽  
Respective Control ◽  
Significant Difference

Eight lots of Cheddar cheese were manufactured with two strains each of Streptococcus faecalis and Streptococcus durans and subjected to combinations of two early cooling treatments (air vs. brine cooling) and two curing temperatures (7.2 and 12.8 C). The enterococcus cultures were used as supplemental starters in combination with a commercial lactic culture. These cheeses were analyzed for microbiological growth and survival, proteolysis, lactic acid development, free fatty acid appearance, and citric acid utilization—each being compared with a control cheese made without enterococci. Results were presented in three previous articles. This series is concluded with the results of organoleptic ana1ysis of the cheeses. Cheeses made with S. faecalis were either comparable to or less desirable than their respective control cheeses. Those made with S. durans, however, were in all instances more desirable than their controls. Cheeses cured at 7.2 C were always given the better scores, but there was no statistically significant difference between air- and brine-cooled cheeses.

Changes in free fatty acids during the ripening of Idiazabal cheese: influence of brining time and smoking

1994 ◽  
Vol 61 (2) ◽  
pp. 281-288 ◽  
Author(s):  
Ana I. Nájera ◽  
Luis J. R. Barron ◽  
Yolanda Barcina
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Free Fatty Acids ◽  
Free Fatty Acid Content ◽  
Acid Content ◽  
Lipolytic Activity ◽  
Fatty Acid Content ◽  
Ripening Period ◽  
Cheese Ripening

SummaryThe effect of brining time and smoking on the free fatty acid content of Idiazabal cheese during ripening was examined. The main free fatty acids considered underwent at least some increase during the first stage of ripening before day 90 and tended to level off around a constant value towards the end of the ripening period. There were significant differences in free fatty acid levels during ripening among cheeses with different brining times and between smoked and unsmoked cheeses. Brining time and smoking exerted marked effects on lipolytic activity during cheese ripening, depending upon the free fatty acid involved and ripening time. In general, brining and smoking led to increases in free fatty acid levels at the end of the ripening period; the different behaviour of butyric acid may be due to a specific lipolytic activity.

Effect of Moist Heat Treatment on Sensory Qualities of Peanut Kernels

1979 ◽  
Vol 6 (2) ◽  
pp. 93-95
Author(s):  
L. R. Beuchat ◽  
P. E. Koehler
Keyword(s):  
Heat Treatment ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Aspergillus Flavus ◽  
Sensory Panel ◽  
Moist Heat ◽  
Organoleptic Characteristics ◽  
Sensory Qualities ◽  
And Control ◽  
Control Samples

Abstract Shelled Florunner cv. peanut kernels adjusted to 12 to 13% moisture were subjected to heat treatments at 60, 90, and 120° C for periods of 1 and 2 hr. Kernels were then dried, oil-roasted, and examined for sensory qualities. Moistened, heated kernels were also inoculated with an aflatoxigenic strain of Aspergillus flavus and analyzed for free fatty acid (FFA) and aflatoxin contents at weekly intervals over a 6-week period of incubation at 30°C. Treatment of moist kernels at 60°C for 1 or 2 hr caused the FFA content to increase from 1.2% (unheated) to 2.2%, whereas treatment at 90 and 120°C for the same periods of time resulted in FFA contents ranging from 10.3 to 13.2%. After 6 weeks, the FFA content of all inoculated and control samples ranged from 11.5 to 14.5%. Sensory panel evaluations of uninoculated, roasted kernels indicated that moist heat treatment at 60°C did not significantly (P ≤ 0.05) alter organoleptic characteristics; treatment at 90°C for 2 hr resulted in significantly lower scores for texture and flavor, whereas treatment at 120°C resulted in a general decrease in all sensory qualities. Kernels heated prior to inoculation with A. flavus did not appear to support growth as well as did unheated kernels early in the 6-week test period.

Effect of proteolytic raw milk psychrotrophs on Cheddar cheese-making with stored milk

1979 ◽  
Vol 46 (3) ◽  
pp. 497-509 ◽  
Author(s):  
Barry A. Law ◽  
Anthony T. Andrews ◽  
Allan J. Cliffe ◽  
M. Elisabeth Sharpe ◽  
Helen R. Chapman
Keyword(s):  
Gel Electrophoresis ◽  
Lipolytic Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Cheddar Cheese ◽  
Raw Milk ◽  
Water Soluble ◽  
N Losses ◽  
Cheese Making ◽  
Psychrotrophic Bacteria ◽  
Colony Forming Units

SummaryThe effect of proteolytic, psychrotrophic strains of Pseudomonas fluorescens, Ps. putida and Acinetobacter spp. on cheese-making with stored milk has been investigated. Ps. fluorescens and Ps. putida growing for 72 h in raw milk at 7·5 °C to levels of approx. 107 colony-forming units/ml caused a low degree of β- and к-casein breakdown detectable by gel electrophoresis, but this was insufficient to affect N losses in whey or cheese yields. Variations in cheese-making times with pasteurized milks were not attributable to the counts of psychrotrophs in the corresponding raw milks. The water-soluble and TCA-soluble N fractions of maturing cheeses were unaffected by psychrotroph counts in raw milks, but small differences in levels of casein fractions of cheeses made from milks stored for 72 h were detected by quantitative polyacrylamide gel electrophoresis. The incidence of casein breakdown in raw milk and subsequently in cheese were not necessarily related. None of the cheeses developed off flavour related to excessive protein breakdown but many became lipolytically rancid, despite the selection of strains with low lipolytic activity on a diagnostic medium. It is concluded that the numbers of psychrotrophic bacteria likely to occur in stored raw milk under commercial conditions are unlikely to cause significant changes in the yields or quality of Cheddar cheese through their proteolytic activity.

scholarly journals The Lipolytic Activity of Antithrombin III

1977 ◽  
Author(s):  
M. Nakagawa ◽  
S. Okuda ◽  
M. Watada ◽  
H. Ijichi
Keyword(s):  
Myocardial Infarction ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Lipase Activity ◽  
Inhibitory Activity ◽  
Antithrombin Iii ◽  
Lipolytic Activity ◽  
Lipoprotein Lipase Activity ◽  
Coagulation Mechanism ◽  
The Relationship

Antithrombin III in the circulating blood is known to play an important role on the coagulation mechanism of the blood and is reported to be decreased in its amount on the cases of myocardial infarction and arteriosclerosis, in the meanwhile the arteriosclerosis has been considered to be one of thrombogenic factors. This research was designed to investigate the effects of antithrombin III on the relationship between fibrin formation and atherosclerosis.Antithrombin III was purified from human defibrinated plasma by Heparin Sepharose Affinity Chromatography. Using this antithrombin III as an enzyme, its lipolytic activity was assayed spectrophotometrically detecting the produced free fatty acid from various substrates, Intralipid, Triolein, and Human Chylomicron respectively. Lipoprotein lipase activity was detected in the purified antithrombin III. Intralipid was hydrolyzed to a greater extent than triolein or chylomicron and it is concluded that antithrombin III in the circulating blood has not only the inhibitory activity of thrombin but also has the lipolytic activity. From these observations it is considered that this lipolytic activity is beneficial for preventing the developement of atherosclerosis and also of thrombosis.

Involvement of fungi in the increase of free fatty acids in stored soybeans

1985 ◽  
Vol 31 (9) ◽  
pp. 799-803 ◽  
Author(s):  
N. Lisker ◽  
A. Ben-Efraim ◽  
Y. Henis
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Relative Humidity ◽  
Free Fatty Acids ◽  
Seed Coat ◽  
Seed Treatment ◽  
Lipolytic Activity ◽  
Soybean Seeds ◽  
Aspergillus Candidus

Application of the fungicide Captan to whole soybean seeds stored at 85% relative humidity did not prevent either the development of the natural fungal population underneath the seed coat or the increase of free fatty acids. At 65 and 75% relative humidity the increase in free fatty acids and fungi development during storage were lower than at 85% relative humidity, but even at these lower levels no differences were observed between Captan-treated and nontreated seeds. In split soybeans, where fungi developed profusely on the unprotected damaged site of the seed, treatment with Captan or thiourea resulted in free fatty acid values significantly lower than those of the untreated controls. The fungi most frequently isolated from stored soybeans were Aspergillus candidus, A. ruber, A. versicolor, and Penicillium cyclopium, all of which showed lipolytic activity. Inoculation of intact soybean seeds with these fungi did not cause an increase in free fatty acids as compared with noninoculated controls, probably because the intact seed coat prevented the penetration of the inoculated fungus. The similar increase in free fatty acids in both the inoculated and the noninoculated controls was probably caused by the internal mycoflora in both treatments. Since fungicide treatments prevented the increase of free fatty acid levels in all cases where the fungicide could reach those sites at which fungi developed, it was concluded that fungi play an important role in the increase of free fatty acids in stored soybeans.

scholarly journals The basal free fatty acid concentration in human saliva is related to salivary lipolytic activity

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Eric Neyraud ◽  
Stéphanie Cabaret ◽  
Hélène Brignot ◽  
Claire Chabanet ◽  
Hélène Labouré ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Acid Concentration ◽  
Lipolytic Activity ◽  
Human Saliva ◽  
Fatty Acid Concentration ◽  
Free Fatty Acid Concentration
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