ESTIMATION OF LIPASE IN DAIRY PRODUCTS: III. LIPASE ACTIVITY IN CULTURES OF MICRO-ORGANISMS AND IN CHEESE

1949 ◽  
Vol 27f (12) ◽  
pp. 499-503 ◽  
Author(s):  
D. J. Lubert ◽  
L. M. Smith ◽  
H. R. Thornton
Keyword(s):  
Lipase Activity ◽  
Dairy Products ◽  
Lipolytic Activity ◽  
Skim Milk ◽  
Preceding Paper ◽  
Cheddar Cheese ◽  
Titration Method ◽  
Number Of Species ◽  
The One ◽  
Micro Organisms

The lipolytic activity in skim milk cultures of micro-organisms representing a number of species and genera were studied by the extraction–titration method described in the preceding paper. No evidence was found of a bacterial lipase having an activity optimum on the acid side of neutrality. No lipase active at approximately pH 5.0 was demonstrated in 20 samples of commercial cheddar cheese of varying age or one sample of blue veined cheese on measurement by the extraction–titration method or by the Peterson et al. method. Weak lipolytic activity was found in one sample of blue veined cheese by the extraction–titration method. No lipolytic activity at pH 8.5 was demonstrated by the extraction–titration method in the one sample of cheese tested at this pH.

ESTIMATION OF LIPASE IN DAIRY PRODUCTS: II. AN EXTRACTION–TITRATION METHOD FOR THE ESTIMATION OF BACTERIAL LIPASE

1949 ◽  
Vol 27f (12) ◽  
pp. 491-498 ◽  
Author(s):  
D. J. Lubert ◽  
L. M. Smith ◽  
H. R. Thornton
Keyword(s):  
Lipase Activity ◽  
Dairy Products ◽  
Skim Milk ◽  
Reaction Medium ◽  
Ether Extract ◽  
Titration Method ◽  
Wide Ph Range ◽  
Ph Range

A method of estimating bacterial lipase is presented that is believed to be more nearly quantitative than any other at present available. The method is based on the titration of acids in an ether extract of a skim milk culture to following a 30 mm period of lipase activity at 37 °C. It is shown that ether-soluble acids carried into the reaction medium do not interfere with the measurements and that ether-soluble acids are not produced from protein or lactose during the test. The method is applicable over a sufficiently wide pH range to make it generally adaptable in bacteriology.

ESTIMATION OF LIPASE IN DAIRY PRODUCTS: I. AN EXTRACTION-TITRATION METHOD FOR THE ESTIMATION OF MILK LIPASE

1949 ◽  
Vol 27f (12) ◽  
pp. 483-490 ◽  
Author(s):  
L. M. Smith ◽  
D. J. Lubert ◽  
H. R. Thornton
Keyword(s):  
Enzymatic Hydrolysis ◽  
Butyric Acid ◽  
Lipase Activity ◽  
Dairy Products ◽  
Ether Extract ◽  
Titration Method ◽  
Micro Organisms ◽  
Hydrolysis Of

A procedure has been outlined for the estimation of milk lipase. The method is based on the titration of an ether extract of butyric acid derived from the enzymatic hydrolysis of tributyrin under standardized conditions. Some of the fundamental factors involved in the procedure have been discussed. It is suggested that modifications of the method may be used to study lipase activity in other dairy products and in cultures of micro-organisms.

Development of a Multiplex Polymerase Chain Reaction Assay for Detection and Differentiation of Staphylococcus aureus in Dairy Products†

2001 ◽  
Vol 64 (5) ◽  
pp. 664-668 ◽  
Author(s):  
SUDHIR TAMARAPU ◽  
JOHN L. McKILLIP ◽  
MARYANNE DRAKE
Keyword(s):  
Staphylococcus Aureus ◽  
Polymerase Chain Reaction ◽  
Multiplex Pcr ◽  
Dairy Products ◽  
Multiplex Polymerase Chain Reaction ◽  
Skim Milk ◽  
Cheddar Cheese ◽  
Polymorphism Analysis ◽  
Chain Reaction ◽  
Polymerase Chain

A multiplex polymerase chain reaction (PCR) assay was developed for the detection and differentiation of enterotoxigenic Staphylococcus aureus in dairy products. A solvent extraction procedure was successfully modified for extraction of S. aureus DNA from 10 ml of artificially contaminated skim milk or 20 g cheddar cheese. Primers targeting the enterotoxin C gene (entC) and thermostable nuclease gene (nuc) were used in the multiplex PCR. PCR products were confirmed using restriction fragment length polymorphism analysis. DNA was consistently quantified and amplified by uniplex PCR from 10 CFU/ml of S. aureus in skim milk or 10 CFU/20 g cheddar cheese. The sensitivity of the multiplex PCR was 100 CFU/ml of skim milk or 100 CFU/20 g cheddar cheese. The developed methodology allows presumptive identification and differentiation of enterotoxigenic S. aureus in less than 6 h.

337. The supplementary relationships between the proteins of dairy products and those of bread and potato as affected by the method of feeding. With a note on the value of soya-bean protein

1946 ◽  
Vol 14 (3) ◽  
pp. 330-339 ◽  
Author(s):  
Kathleen M. Henry ◽  
S. K. Kon
Keyword(s):  
Dairy Products ◽  
Protein Intake ◽  
Skim Milk ◽  
Cheddar Cheese ◽  
Soya Bean ◽  
White Bread ◽  
Biological Value ◽  
Bean Flour ◽  
True Digestibility ◽  
Bean Protein

1. The biological value of proteins at an 8% level of protein intake measured on rats by the method of Mitchell (7, 10) was 52 for white bread of 73% extraction, 76 for Cheddar cheese, 75 for a mixture of both foods when each supplied 50% of the protein, and 67 when the two sources of protein were given on alternate days. The true digestibilities were, respectively, 99, 100, 98 and 99.2. Similar experiments with dried skim milk and dried cooked potatoes yielded biological values of 71 for potato, 89 for milk, 86 for the mixture and 81 for the substances fed separately on alternate days. The true digestibilities were, respectively, 82, 90, 82 and 87.3. An attempt to carry out experiments of the same type with dried whey and dried potato failed because of deaths of some rats receiving the whey diet, probably because of its high content of lactose. A biological value of 76 was obtained for the potato proteins and of 70 for a mixture of whey and potato in which whey supplied 25% of the protein. The true digestibilities were, respectively, 82 and 68.4. The biological value and the true digestibility of the proteins of a sample of edible soya-bean flour were, respectively, 73 and 90.5. It is concluded that there is a marked supplementary relationship between the proteins of milk and potato and those of bread and cheese when the members of each pair supply equal amounts of protein and when they are given together. No supplementary relationship is exhibited when the sources of protein are given separately on alternate days.

Fate of Organochlorine Pesticides During Processing of Milk into Dairy Products

1970 ◽  
Vol 53 (1) ◽  
pp. 127-139
Author(s):  
C F Li ◽  
R L Bradley ◽  
L H Schultz
Keyword(s):  
Dairy Products ◽  
Cheese Whey ◽  
Skim Milk ◽  
Cheddar Cheese ◽  
Bactericidal Action ◽  
Milk Products ◽  
Condensed Milk ◽  
Lactating Dairy Cows ◽  
Whole Milk ◽  
Spray Dried

Abstract Two lactating dairy cows per group were fed selected pesticides dissolved in organic solvents and mixed into a grain concentrate for a two week period. The reference pesticides used in this study were dieldrin; a mixture of heptachlor, DDT, and lindane; toxaphene; chlordane; endosulfan (Thiodan); and dicofol (Kelthane). The milk from these contaminated cows was collected and processed into the following dairy products: pasteurized whole milk, 30% cream, butter, spray-dried whole milk, condensed whole milk, sterilized condensed whole milk, and Cheddar cheese. The byproducts (skim milk, buttermilk, and Cheddar cheese whey) from manufacturing these products were also saved for subsequent analysis. The residues in these dairy products and byproducts were extracted, cleaned up, and analyzed by electron capture gas chromatography. The 30% cream, condensed milk, and pasteurized milk were analyzed at 0, 7, and 14 days and Cheddar cheese, spray-dried milk, butter, and sterilized condensed milk after storage for 0, 3, and 6 months. The results indicated that, in general, the pesticides used were very stable for ordinary dairy processing operations and remained essentially unchanged even after storage at refrigeration and room tempera-tures for 6 months. However, dieldrin, lindane, and chlordane showed a 27, 34, and 11% decrease, respectively, for spray-dried products and the concentration of dicofol showed a slight decrease in the sterilized condensed whole milk products, whereas the concentration of DDE extracted from the products stored 3 and 6 months was generally less than the amount extracted initially. In manufacturing Cheddar cheese, most of the pesticides showed some bacteriostatic or bactericidal action against starter microorganisms. Generally the pesticide residues were found in greater concentration (on a fat basis) in the skim milk, buttermilk, and whey than in products from which these were derived. This might be attributable to the affinity of the residues for the lipoprotein portion of the products. Concentrations of dieldrin and toxaphene increased slightly during storage of the milk and milk products, suggesting that a reorientation occurred.

scholarly journals Whey/Broken Chickpea Extract for manufacture of Probiotic Frozen Yoghurt

2019 ◽  
Vol 7 (3) ◽  
pp. 807-818
Author(s):  
Fawzia Abd Rabo ◽  
M. A. Azzam ◽  
Omaima M. Dewidar
Keyword(s):  
Lactobacillus Acidophilus ◽  
Dairy Products ◽  
Milk Powder ◽  
Skim Milk ◽  
Streptococcus Thermophilus ◽  
Skim Milk Powder ◽  
Bifidobacterium Bifidum ◽  
Beneficial Effects ◽  
Probiotic Dairy Products ◽  
Micro Organisms

Probiotic frozen yoghurt is one of the ideal probiotic dairy products for delivery of live probiotic micro-organisms to human diet and thus to human intestinal tract. Probiotic micro-organisms have beneficial effects on human health. These benefits include improvements to the intestinal microflora, anti tumoral activity, reduction of cholesterol in the blood, increased immune response and other health benefits. In this study five probiotic frozen yoghurt mixtures were prepared, Acontrol (mainly from fresh skim milk and skim milk powder), B (mainly from whey/broken chickpea extract and milled chickpea grains), AB25 (75% A + 25% B), AB50 (50% A + 50% B) and AB75 (25% A + 75% B). The resultant frozen yoghurts were sensory evaluated. Panelists arranged their preference as Acontrol> AB25> AB50> AB75> B. Physically, the melting resistance of frozen yoghurt increased with the increase of chickpea ingredients. Nutritionally, chickpea frozen yoghurt contained nutrients not found in Acontrol such as dietary fibers, iron, branched chain amino acids, zinc and vitamins B3, B9 and E. Microbiologically, the viable counts of ABT culture strains (Lactobacillus acidophilus + Bifidobacterium bifidum + Streptococcus thermophilus) in all frozen yoghurt samples remained within the limits recommended for the probiotic products. Microbiologically, large numbers (> 107 cfu/g) of probiotic microorganisms present in all stored samples indicated that the resulting frozen yogurt could represent a good source of Lactobacillus acidophilus and Bifidobacterium bifidum and commercially, this product was included in probiotic dairy products.

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.

ESTIMATION OF LIPASE IN DAIRY PRODUCTS: IV. LIPOLYTIC ACTIVITY OF PSEUDOMONAS FLUORESCENS

1949 ◽  
Vol 27f (12) ◽  
pp. 504-509 ◽  
Author(s):  
D. J. Lubert ◽  
L. M. Smith ◽  
H. R. Thornton
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Fluorescens ◽  
Calcium Chloride ◽  
Dairy Products ◽  
Lipolytic Activity ◽  
Skim Milk ◽  
Reaction Medium ◽  
Nutrient Broth ◽  
Optimum Ph ◽  
Coli Growth

The lipolytic activity of a strain of Pseudomonas fluorescens was investigated. Under the investigational conditions activity was greatest when the reaction medium was at approximately pH 8.9 at the start of the reaction period and when the reaction was carried out at approximately 42 °C. The optimum pH for activity by this enzyme was found to be between 8 and 9. This lipase is not specific for tributyrin but hydrolyzes tricaproin and tricaprylin as well, although with decreasing ease. Calcium chloride inhibited rather than enhanced the activity. Lipolytic activity was greater in nutrient broth-base media than in skim milk but the latter was more satisfactory with which to work. Lypolytic activity and fluorescence were not found to be related. Nutrient broth freed of carbohydrate by Escherichia coli growth and heat-sterilized stimulated production of fluorescence.

ALLELOPATHIC EFFECTS OF PARTHENIUM HYSTEROPHORUS ON GERMINATION OF RAPHANUS SATIVA SEEDS

2018 ◽  
Vol 6 (26) ◽  
Author(s):  
Jitendra Rajpoot
Keyword(s):  
Parthenium Hysterophorus ◽  
Allelopathic Effects ◽  
The One ◽  
Micro Organisms ◽  
Injurious Effects

The term ‘allelopathy’ was coined to describe the effect of the one plant on neighbouring plants. The word Allelopathy has been derived from two Greek words Allelon meaning ‘each other’ and Pathos meaning ‘to suffer’ i.e. the injurious effects of one plant upon another However, Molisch (1937) coined this term which refers to all biochemical interactions (stimulatory and inhibitory) among plants, including micro-organisms

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