Lipolysis in Milk. I. Determination of Free Fatty Acid and Threshold Value for Lipolyzed Flavor Detection

Pillay, Visva; Myhr, A.N.; Gray, J. I.

doi:10.3168/jds.s0022-0302(80)83070-0

Cited by 18 publications

(5 citation statements)

References 4 publications

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“…The advantage of these methods is that several studies have evaluated the sensory threshold for rancidity. However, the threshold scores in these studies vary from 1.25 to 2.0 mmol/100 g fat [11][12][13]. More qualitative and quantitative information can be obtained from HPLC-and GC-based methods, for example by using solid phase microextraction-GC.…”

Section: Introductionmentioning

confidence: 99%

Effect of Homogenization Temperature and Pressure on Lipoprotein Lipase Activity and Free Fatty Acids Accumulation in Milk

Wiking¹,

Dickow²

2013

FNS

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This study demonstrated that homogenization did not increase the activity of lipoprotein lipase (LPL) in spite of a fast accumulation of free fatty acids (FFA). Two homogenization pressures (100 and 170 bar) and two temperatures (40℃and 50℃) were examined. The activity of LPL was analyzed and the formation of FFA was measured with two different methods, the B.D.I.-method and a nonesterified fatty acids (NEFA) method. A homogenization temperature of 50℃ resulted in a decreased LPL activity compared to 40℃. No effect of homogenization pressure was found. Analyzing FFA concentration with the B.D.I.-method resulted in significant effect of homogenization temperature and no effect of pressure. The largest formation of FFA was found in milk homogenized at 40℃. Using the NEFA method, another result was obtained, indicating no effect of homogenization temperature and a larger FFA accumulation at 100 bar than at 170 bar. Both analytic methods demonstrated significant production of FFA during 60 min incubation at homogenization temperature after treatment. The level of FFA in the milk samples immediately after homogenization was very high, demonstrating that LPL cleaves the triglycerides very rapidly when the native membrane was damaged. The regression between the B.D.I.-method and the NEFA was fair in the interval between 4 and 14 mmol/100 g fat, whereas at higher concentrations, the correlation was poor

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Section: Introductionmentioning

confidence: 99%

Effect of Homogenization Temperature and Pressure on Lipoprotein Lipase Activity and Free Fatty Acids Accumulation in Milk

Wiking¹,

Dickow²

2013

FNS

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“…The FFA content of milk fat is commonly between 0.5 and 1.2 mmol/100 g (Hanus et al, 2008). Sensory evaluation based on flavor scores by Pillay et al (1980) showed significant differences between reference milk samples, indicating that the sensory threshold for rancid flavor lies in the range of 4.5 mmol/100 g of fat. Results in this study showed FFA levels exceeding the sensory threshold at 3 and 4 h after inoculation with Staph.…”

Section: Short Communicationmentioning

confidence: 98%

Short communication: Lipolytic activity on milk fat by Staphylococcus aureus and Streptococcus agalactiae strains commonly isolated in Swedish dairy herds

Vidanarachchi

Lundh

et al. 2015

Journal of Dairy Science

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The objective of this study was to determine the lipolytic activity on milk fat of 2 bovine mastitis pathogens, that is, Staphylococcus aureus and Streptococcus agalactiae. The lipolytic activity was determined by 2 different techniques, that is, thin-layer chromatography and an extraction-titration method, in an experimental model using the most commonly occurring field strains of the 2 mastitic bacteria isolated from Swedish dairy farms. The microorganisms were inoculated into bacteria-free control milk and incubated at 37°C to reflect physiological temperatures in the mammary gland. Levels of free fatty acids (FFA) were analyzed at time of inoculation (t=0) and after 2 and 6h of incubation, showing significant increase in FFA levels. After 2h the FFA content had increased by approximately 40% in milk samples inoculated with Staph. aureus and Strep. agalactiae, and at 6h the pathogens had increased FFA levels by 47% compared with the bacteria-free control milk. Changes in lipid composition compared with the bacteria-free control were investigated at 2 and 6h of incubation. Diacylglycerols, triacylglycerols, and phospholipids increased significantly after 6h incubation with the mastitis bacteria, whereas cholesterol and sterol esters decreased. Our results suggest that during mammary infections with Staph. aureus and Strep. agalactiae, the action of lipases originating from the mastitis pathogens will contribute significantly to milk fat lipolysis and thus to raw milk deterioration.

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“…Subsequently, 2 mL of methyl alcohol was added to each tube, 200 μL of fat were extracted and transferred into a tube and dissolved in 1 mL of solvent for fat (petroleum ether: n-propanol ratio 4 : 1 v/v and methyl alcohol: water 50 : 50). Finally, 2 drops of phenolphthalein were added and the samples were subsequently titrated with KOH 0.01 N. Lipid oxidation was measured as the degree of free fatty acid (ADV), defined as milliequivalents of alkali (KOH) per 100 g of fat and calculated as follows [28]:…”

Section: Protein Oxidationmentioning

confidence: 99%

Effect of the Application of Cold Plasma Energy on the Inactivation of Microorganisms, Proteins, and Lipids Deterioration in Adobera Cheese

Uscanga

Calderón‐Santoyo

Sánchez

et al. 2022

Journal of Food Quality

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Cheeses are perishable foods that must fulfill sanitary and quality requirements according to the parameters established globally. Plasma as a nonthermal inactivation technique has been a current research topic for food preservation, so the objective of this work was to study the effect of plasma energy against microorganisms in Adobera cheese (traditional Mexican cheese) as well as evaluate the possible degradation of lipids and protein. 108 CFU/mL of Escherichia coli ATCC 25922, Salmonella ATCC13076, and Staphylococcus aureus ATCC 6538 were inoculated at 0.5 g of Adobera cheese and were subjected to an energy of 30 volts, in a dielectric barrier discharge reactor (DBDR) at intervals of times 1, 3, 5, 7, 10, and 15 min. A flow of a mixture of air and helium at 96% purity was used. The decimal reduction time (D) was determined, and the oxidation of proteins and lipids was analyzed after each treatment. The results showed an annihilating effect of plasma on the indicator bacteria under study, and a reduction of 5 logarithmic cycles was obtained. The maximum degree of lipid oxidation was 23 acid degree values (ADV) after 7 min of exposure to plasma. The oxidation of proteins showed a direct and proportional relationship between the formation of carbonyl groups with the percentage significant loss to the concentration of carbonyl groups with the concentration of protein oxidation, after 3 min of exposure to cold plasma levels of 82% and 99% oxidation of Adobera cheese protein and free casein, respectively. We conclude that the plasma energy applied to Adobera cheese is an effective treatment to inactivate bacteria. However, there is the possibility of causing changes in taste and odor, due to the release of fatty acids and the oxidation of proteins.

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Lipolysis in Milk. I. Determination of Free Fatty Acid and Threshold Value for Lipolyzed Flavor Detection

Cited by 18 publications

References 4 publications

Effect of Homogenization Temperature and Pressure on Lipoprotein Lipase Activity and Free Fatty Acids Accumulation in Milk

Effect of Homogenization Temperature and Pressure on Lipoprotein Lipase Activity and Free Fatty Acids Accumulation in Milk

Short communication: Lipolytic activity on milk fat by Staphylococcus aureus and Streptococcus agalactiae strains commonly isolated in Swedish dairy herds

Effect of the Application of Cold Plasma Energy on the Inactivation of Microorganisms, Proteins, and Lipids Deterioration in Adobera Cheese

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