Heat Inactivation of Bile Salt-Stimulated Lipase Activity in Human Milk and Colostrum1

1983 ◽  
Vol 46 (6) ◽  
pp. 525-527
Author(s):  
S. H. L. PAN ◽  
C. W. DILL ◽  
E. S. ALFORD ◽  
R. L. RICHTER ◽  
C. GARZA
Keyword(s):  
Human Milk ◽  
Bile Salt ◽  
Lipase Activity ◽  
Bovine Milk ◽  
Heat Inactivation ◽  
Assay Procedure ◽  
Ph Stat

Time-temperature relationships for heat-inactivation of bile salt-stimulated lipase activity in human milk and colostrum were systematically measured using a pH-stat assay procedure with triolein as substrate. The enzyme was not affected in either menstruum at 45°C for 40 min. The enzyme was destroyed almost instantaneously at 60°C, and was slightly more heat-sensitive in colostrum than in milk. The bile salt-stimulated lipase(s) in human milk was more heat sensitive than lipase in bovine milk.

Heat Stability of the Bile Salt-Stimulated Lipase in Human Milk Fortified with Sodium Taurocholate1

1988 ◽  
Vol 51 (4) ◽  
pp. 310-313 ◽  
Author(s):  
H. L. PAN ◽  
C. W. DILL ◽  
E. S. ALFORD ◽  
S. L. DILL ◽  
C. A. BAILEY ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Human Milk ◽  
Bile Salt ◽  
Lipase Activity ◽  
Sodium Taurocholate ◽  
Heat Stability ◽  
Heat Inactivation ◽  
Temperature Differential ◽  
Heat Stable ◽  
Control Samples

Time-temperature relationships for heat-inactivation of the bile salt-stimulated lipase activity were compared in whole human milk and in the same product fortified to 9 mM/ml with sodium taurocholate. Heat treatments were varied from 45 to 70°C for times ranging from 15s to 40 min. Enzyme activity was more heat stable in human milk fortified with taurocholate than in control samples. The temperature required for the onset of heat inactivation at 30-min holding time was increased from 45°C for control samples to 60°C following addition of taurocholate. A temperature differential of approximately 12°C was required in the fortified milks to produce inactivation equivalent to that observed in the control milks over the heating range studied.

Influence of processing temperature and seasonal change in diet on lipase activity and lipolysis during the mechanical separation of bovine milk

1985 ◽  
Vol 52 (2) ◽  
pp. 255-266 ◽  
Author(s):  
Eric C. Needs ◽  
Malcolm Anderson ◽  
Stuart J. Payne ◽  
Elizabeth A. Ridout
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Seasonal Change ◽  
Lipase Activity ◽  
Bovine Milk ◽  
Skim Milk ◽  
Relative Activity ◽  
Heat Inactivation ◽  
Processing Temperature ◽  
Original Activity

SUMMARYThe effect of separating conditions on lipase activity and free fatty acid levels in preheated milk, cream and skim milk was measured on nine occasions during a 12-week period covering the seasonal change from winter feeding to summertime grazing. This change consisted of four periods each representing a different type of forage intake, namely: silage, kale, daytime grazing and 24 h grazing. Milk was separated at 30, 40, 50 and 60°C with preheating times of 10, 25 and 55 s. Results were expressed both as absolute values and in terms of changes relative to the original unheated milk. Lipase activity and free fatty acid concentration were significantly reduced as separation temperature increased but were not influenced by holding time. The loss of activity in cream was progressive so that at 60°C only 40% of the original activity remained. Up to 50°C little change occurred in preheated milk or skim milk activity, while at 60°C 83 and 76% respectively of the original activity remained. The amount of activity calculated to be associated with the fat fraction of the cream also decreased with temperature. Activity varied significantly with date; maximum values were observed during the first 3 weeks of summertime grazing. Relative activity values indicated that the susceptibility of milk lipase to heat inactivation also varied with date. Lipolysis was also significantly affected by date. Cream free fatty acid levels were lower during the period of daytime grazing and were significantly higher than those in preheated milk. The correlation between lipase activity and free fatty acid levels was generally poor, accounting for between 0 and 34% of the variance. Possible reasons for the effect of separating temperature on lipolysis in cream are discussed.

Lipolytic Activity During Storage of Human Milk: Stability of the Bile Salt-Stimulated Lipase1

1983 ◽  
Vol 46 (11) ◽  
pp. 994-996 ◽  
Author(s):  
C. W. DILL ◽  
C. T. CHEN ◽  
E.S. ALFORD ◽  
R. L. EDWARDS ◽  
R. L. RICHTER ◽  
...  
Keyword(s):  
Human Milk ◽  
Bile Salt ◽  
Lipase Activity ◽  
Room Temperature ◽  
Lipolytic Activity ◽  
Skim Milk ◽  
C Storage ◽  
Whole Milk ◽  
Freeze Dried ◽  
Initial Drop

Bile salt-stimulated lipase activity was monitored in fresh human milk and skim milk during refrigerated (4°C) and frozen (−20°C) storage, and in the lyophilized milks stored at −20°C and at room temperature. Following a sharp initial drop to approximately 77% of the original lipase activity, lipase was relatively stable in frozen or freeze-dried milks during 180 d of storage at −20°C. Activity losses were greatest (P < .05) in freeze-dried whole milks and skim milks stored at room temperature, approximating a 30% loss during 30 d of storage. Lipase activity was stable during refrigerated (4°C) storage of whole milk for 1 week.

A Retrospective Analysis of the Effects of an Exclusively Human Milk Protein Diet on Neonatal Feeding Tolerance

2020 ◽  
Author(s):  
Jessica Wickland ◽  
Christine Wade ◽  
Becky Micetic ◽  
Keith Meredith ◽  
Gregory Martin
Keyword(s):  
Birth Weight ◽  
Human Milk ◽  
Milk Protein ◽  
Very Low Birth Weight ◽  
Bovine Milk ◽  
Milk Diet ◽  
Vlbw Infants ◽  
Key Points ◽  
Human Milk Protein ◽  
Feeding Tolerance

Objective This study was aimed to evaluate the effect of human milk protein fortifier (HMPF) versus bovine milk protein fortifier (BMPF) on feeding tolerance defined as the time to reach full feeds and necrotizing enterocolitis (NEC) in premature very low birth weight (VLBW) infants. Study Design A retrospective review using the BabySteps Database included 493 infants born ≤33 weeks of gestational age and ≤1,250 g (g) birth weight. A total of 218 infants fed a human milk diet (HMD) with BMPF were compared with 275 infants fed an HMD with HMPF. Results Full feeds were reached significantly sooner in the HMPF group (median: 14 vs. 16 days, p = 0.04). Weight at full feeds was significantly lower in the HMPF group (1,060 vs. 1110 g, p = 0.03). Conclusion Using HMPF to provide an exclusively HMD allowed VLBW infants to achieve full feeds sooner, but did not affect rate of NEC compared with using a BMPF with an HMD. Key Points

Bile-Salt-Stimulated Human Milk Lipase: Interaction with Proteins

1988 ◽  
Vol 3 (4) ◽  
pp. 390-402 ◽  
Author(s):  
Charmian J. O'Connor ◽  
Paul A.G. Butler ◽  
Bridget M. Sutton
Keyword(s):  
Human Milk ◽  
Bile Salt

scholarly journals Modification of a phospholipid stabilized emulsion interface by bile salt: effect on pancreatic lipase activity

1998 ◽  
Vol 39 (3) ◽  
pp. 623-632 ◽  
Author(s):  
Martin Wickham ◽  
Martin Garrood ◽  
John Leney ◽  
Peter D.G. Wilson ◽  
Annette Fillery-Travis
Keyword(s):  
Bile Salt ◽  
Pancreatic Lipase ◽  
Lipase Activity ◽  
Salt Effect

scholarly journals Comparison of methods for milk pre-processing, exosome isolation, and RNA extraction in bovine and human milk

2020 ◽  
Author(s):  
Sanoji Wijenayake ◽  
Shafinaz Eisha ◽  
Zoya Tawhidi ◽  
Michael A. Pitino ◽  
Michael A. Steele ◽  
...  
Keyword(s):  
Human Milk ◽  
Biological Fluid ◽  
Rna Extraction ◽  
Bovine Milk ◽  
Total Soluble Protein ◽  
Long Term Storage ◽  
Transmission Electron ◽  
Whole Milk ◽  
Membrane Bound

AbstractMilk is a highly complex, heterogeneous biological fluid that contains bioactive, membrane-bound extracellular vesicles called exosomes. Characterization of milk-derived exosomes (MDEs) is challenging due to the lack of standardized methods that are currently being used for milk pre-processing, exosome isolation, and RNA extraction. In this study, we tested: 1) three pre-processing methods to remove cream, fat, and casein proteins from bovine milk to determine whether pre-processing of whole milk, prior to long-term storage, improves MDE isolations, 2) two commonly-used exosome isolation methods, and 3) four extraction protocols for obtaining high quality MDE RNA from bovine and human milk. MDEs were characterized via Transmission Electron Microscopy (TEM) and Nanoparticle Tracking Analysis (NTA). We also present an optimized method of TEM sample preparation and isolation of total soluble protein from MDEs. Our results indicated that: 1) pre-processing of bovine milk prior to storage does not affect the final exosome yield or the purity, 2) ExoQuick precipitation is better suited for MDE isolation than ultracentrifugation for bovine and human milk, and 3) TRIzol LS produced the highest RNA yield in bovine milk, whereas TRIzol LS, TRIzol+RNA Clean and Concentrator, and TRIzol LS+RNA Clean and Concentrator methods can be used for human milk.

Summary-The Early Feeds: Human Milk Versus Formula and Bovine Milk

PEDIATRICS ◽  
1985 ◽  
Vol 75 (1) ◽  
pp. 157-159
Keyword(s):  
Breast Milk ◽  
Human Milk ◽  
Whey Proteins ◽  
Bovine Milk ◽  
Milk Proteins ◽  
Human Infant ◽  
Postnatal Life ◽  
Human Breast Milk ◽  
Nonprotein Nitrogen ◽  
Casein Protein

Adaptations of the gastrointestinal tract and the immune system that take place during the first year of postnatal life are of great importance, initially facilitating the transition between gestation and lactation, ultimately supporting independent postnatal life. When considering feeding options during the early periods, the roles of human milk, commercially prepared formula, and bovine milk must be evaluated in light of recent knowledge of these adaptations. Since infant feeding practices and the biologic capabilities of infants themselves vary significantly, the question arises as to what is "acceptable" v what is "optimal." NUTRITIONAL PROTEINS At present, evaluations of the amount of protein required for infant growth are based on clinical studies of largē populations and include a "margin of safety" to meet the needs of the individual infant. Based on the assumption that the milk of a given species is best adapted to the nutrient requirements of the young of that species, human infant protein requirements are determined by the protein contribution of human breast milk. Breast-milk proteins are defined broadly as either whey or casein protein with an approximate ratio of 70:30, respectively. The casein portion is divided into three subgroups: α,β and κ casein. Whey proteins are divided into six major subgroups: α-lactalbumin, β-lactoglobulin; lactoferrin; serum-albumin; lysozyme, and immunoglobulins A, G, and M. Numerous nonprotein nitrogen substances including taurine exist as well. Protein Availability Protein concentration of breast milk is approximately 1.2 g/dL when measured as total nitrogen. Nearly 25% of this is nonprotein nitrogen, much of which may not be used for nutritional purposes.

Sign in / Sign up

Export Citation Format

Share Document