587. Fluorescence microscopy of fat in milk and milk powder

1955 ◽  
Vol 22 (2) ◽  
pp. 205-210 ◽  
Author(s):  
N. King
Keyword(s):  
Milk Powder ◽  
Skim Milk ◽  
Storage Conditions ◽  
High Contrast ◽  
Basic Fuchsin ◽  
Fat Globules ◽  
Powder Particles ◽  
Light Fluorescence ◽  
And Storage ◽  
Green Coloration

The fat globules in milk and cream by taking up the fluorescent dye phosphine from aqueous solution are rendered fluorescent, and show under the blue light fluorescence microscope a bright yellowish green coloration against the black background. Even very small fat globules (in homogenized milk, cream, skim milk, or buttermilk) and very thin fat layers on the milk-air boundary or on glass can be distinguished owing to the high contrast.By using glycerol containing two fluorochromes, phosphine for the fat and basic fuchsin for the proteinaceous matter, a very sharp differentiation of these two components in milk-powder particles is attained. Differences in the state of dispersion of fat caused by manufacturing technique and storage conditions, and affecting the properties of powders, are clearly made visible.

Changes in Concentration of Aflatoxin M1 during Manufacture and Storage of Skim Milk Powder

2006 ◽  
Vol 69 (3) ◽  
pp. 682-685 ◽  
Author(s):  
ORGUN DEVECİ ◽  
EMEL SEZGİN
Keyword(s):  
Spray Drying ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Aflatoxin M1 ◽  
Weight Changes ◽  
Sample Weight ◽  
Powder Samples ◽  
And Storage ◽  
Different Levels

In this study, skim milk powder was produced from cow's milk contaminated artificially with aflatoxin M1 (AFM1) at two different levels, 1.5 and 3.5 μg/liter (ppb), and the effects of process stages on the AFM1 contents were investigated. Pasteurization, concentration, and spray drying caused losses of about 16, 40, and 68%, respectively, in AFM1 content of the milk contaminated with 1.5 μg/liter AFM1, and losses of 12, 35, and 59%, respectively, in the milk contaminated with 3.5 μg/liter AFM1. These losses were found to be statisticially significant at the level of P < 0.01. After 3- and 6-month storage periods, AFM1 content of the skim milk powder produced from milk with 1.5 μg/liter AFM1 decreased by 2 and 5%, respectively, whereas these rates were 2 and 4%, respectively, for the skim milk powders made from milk with 3.5 μg/liter AFM1 (after adjustment for sample weight). Changes in AFM1 content of milk powder samples were found statistically insignificant (P > 0.05 and P > 0.01) for 3- and 6-month storage periods.

scholarly journals Effect of skim milk powder and sucrose on quality and storage stability of mango leather

2018 ◽  
Vol 3 (4) ◽  
pp. 41-49
Author(s):  
Adnan Khaliq ◽  
◽  
Moazzam Rafiq Khan ◽  
Samreen Ahsan ◽  
Muhammad Farhan Jahangir Chughtai ◽  
...  
Keyword(s):  
Storage Stability ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
And Storage

Influence of the emulsion droplet type on the rheological characteristics and microstructure of rennet gels from reconstituted milk

2009 ◽  
Vol 76 (3) ◽  
pp. 349-355 ◽  
Author(s):  
Zafir Gaygadzhiev ◽  
Arthur Hill ◽  
Milena Corredig
Keyword(s):  
Elastic Modulus ◽  
Milk Fat ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Tween 20 ◽  
Gel Structure ◽  
Ionic Equilibrium ◽  
Fat Globules ◽  
Reconstituted Milk

Rheological and microstructural properties of rennet-induced milk gels containing different fat globules were studied. Recombined milks were prepared by mixing reconstituted low-heat skim milk powder and anhydrous milk fat emulsified with reconstituted skim milk powder (SMP), sodium caseinate (NaCas), whey protein isolate (WPI) or Tween 20. Final elastic modulus of the rennet gels containing WPI- or Tween 20-stabilized fat globules showed significantly lower values compared with those prepared with SMP-emulsified fat globules. SMP-stabilized fat globules interacted with the continuous casein network reinforcing the gel structure. Confocal micrographs supported the rheological data revealing that gels containing SMP-stabilized fat globules formed a tighter network relative to other treatments. Microscopy images also showed some degree of droplet flocculation in the case of gels containing WPI- or Tween 20-stabilized fat globules, and this was most likely the cause of the increase of elastic modulus of these systems. Contrary to reports for acid-induced casein gels, NaCas-stabilized fat globules hindered the formation of rennet gels. These results illustrate that rennet gel structure is affected by droplet-droplet and droplet-casein interactions, which in turn are determined by the composition of the oil-water interface as well as the ionic equilibrium in the reconstituted milk gels.

scholarly journals Principles of lactose crystallization and rheology of milk protein concentrate

2021 ◽  
Vol 10 (15) ◽  
pp. e577101523028
Author(s):  
Débora Brito Goulart
Keyword(s):  
Milk Protein ◽  
Milk Powder ◽  
Skim Milk ◽  
Moisture Sorption ◽  
Skim Milk Powder ◽  
Protein Concentrate ◽  
Milk Protein Concentrate ◽  
Dairy Ingredients ◽  
And Storage ◽  
Maillard Browning

Milk protein concentrate (MPC) is a commercial designation for dairy ingredients with higher protein and lower lactose content than conventional skim milk powder. Lactose in its amorphous form is found in several spray-dried dairy powders. Amorphous lactose is thermodynamically unstable and can mobilize and crystallize over time under adequate temperature and moisture content. Moisture sorption from the air precedes crystallization, enhancing MPC cohesiveness and caking. This increased humidity results in poor rehydration and dispersibility, lower yield during drying, operation problems, difficulties in handling and storage. Moreover, lactose crystallization in MPC can cause Maillard browning reaction and fat oxidation. To avoid this problem, it is necessary to pre-crystallize lactose as alpha-lactose monohydrate, which is non-hygroscopic, before spray drying. Such a procedure is essential in preventing deterioration of MPC resulting from lactose crystallization or chemical reactions. Additionally, the control of this step is important to obtain specified and reproducible powder, in terms of size and crystallization level. There are various reports on the rheology of milk-based products; however, there is a lack of investigation on concentrated systems. Consequently, the objective of the present work is to review basic concepts of lactose crystallization and rheology of milk protein concentrate.

scholarly journals Viability of Lactobacillus plantarum TISTR 2083 in Protectant during Low-Temperature Drying and Storage

2021 ◽  
Vol 50 (8) ◽  
pp. 2229-2240
Author(s):  
Abdullah Al Mamun ◽  
Payap Masniyom ◽  
Jaruwan Maneesri
Keyword(s):  
Low Temperature ◽  
Lactobacillus Plantarum ◽  
Silica Gel ◽  
Starter Culture ◽  
Skim Milk ◽  
Viable Cell ◽  
Storage Conditions ◽  
Rice Starch ◽  
Low Temperature Drying ◽  
And Storage

Low-temperature drying was applied as simple and low cost drying technique for the production of dried Lactobacillus plantarum TISTR 2083, which was isolated from traditional starter of Ka-nom Tuay-fu. To improve the survival of L. plantarum TISTR 2083 during drying and storage, five different protectants and two carrier materials were investigated. These include sucrose, trehalose, maltodextrin, skim milk, and L-glutamate sodium salt (L-GSS) as protectant and rice starch and rice flour as carrier material. Whereas, skim milk as protectant with rice starch resulted in higher viable cell (8.71 log CFU/g) after drying by hot air oven at 40 °C. Different concentration 5, 10, and 15% (w/v) skim milk also investigated to check the effect of skim milk concentration on cell viability. L. plantarum TISTR 2083 starter powder was in different storage conditions to check the storage stability. After 90 days of storage, starter powder stored at 4 °C with silica gel and without silica gel had more than 80% survival rate, while there was no viable cell that stored in room temperature with silica gel. The result showed the production and storage conditions of high viability L. plantarum TISTR 2083, which can be used as starter culture for further fermented product development and as probiotic.

Microscopic observations on the dispersibility of milk powder particles in some organic liquids

1961 ◽  
Vol 28 (3) ◽  
pp. 277-283 ◽  
Author(s):  
N. King ◽  
P. D. Shimmin
Keyword(s):  
Propylene Glycol ◽  
Guanidine Hydrochloride ◽  
Sodium Dodecyl ◽  
Milk Powder ◽  
Skim Milk ◽  
Water Soluble ◽  
Organic Liquids ◽  
Thin Membranes ◽  
Powder Particles ◽  
Spray Dried

SummaryBy the application of different water-soluble organic compounds and some protein-denaturing reagents dissolved therein, several stages in the dispersion of milk powder particles can be distinguished. The particles first swell, and agglomeration or coalescence follows. However, no dispersion necessarily takes place at this stage, as indicated by the absence of casein micelles in the surrounding liquid. In the initial stage of self-dispersion, ‘dispersion streams’ emanating from the powder particles may be observed. In certain cases, particularly with spray dried skim-milk, thin membranes may be perceived around the swollen and dispersing powder particles. The dispersibility is dependent upon the fat content of the powder and the method of manufacture.With propylene glycol and butylene glycol no dispersion of powder particles took place. However, the hydrogen-bond breaking reagents, urea, guanidine hydrochloride and sodium salicylate, as well as an anionic detergent, sodium dodecyl sulphate dissolved in propylene glycol, caused dispersion of powder particles, particularly in spray dried powders. The limited dispersibility of roller dried powders in water could be greatly enhanced by the same reagents.With water-insoluble liquids enough moisture penetrated through the medium to cause the crystallization of lactose in powder particles.

Barley seed storage under controlled conditions

2019 ◽  
pp. 140-150 ◽  
Author(s):  
O. A. Zadorozhna ◽  
T. P. Shyianova ◽  
M.Yu. Skorokhodov
Keyword(s):  
Hordeum Vulgare ◽  
Moisture Content ◽  
Spring Barley ◽  
Seed Storage ◽  
Growing Season ◽  
Storage Conditions ◽  
Meteorological Conditions ◽  
Hordeum Vulgare L ◽  
The Relationship ◽  
And Storage

Seed longevity of 76 spring barley gene pool samples (Hordeum vulgare L. subsp. distichon, convar. distichon: 56 nutans Schubl., two deficience (Steud.) Koern., two erectum Rode ex Shuebl., two medicum Koern.; convar. nudum (L.) A.Trof.: one nudum L. та subsp. vulgare: convar. vulgare: nine pallidum Ser., three rikotense Regel.; convar. coeleste (L.) A.Trof.: one coeleste (L.) A.Trof.) from 26 countries, 11 years and four places of reproduction was analyzed. Seeds with 5–8% moisture content were stored in chamber with unregulated and 4oC temperature. The possibility of seed storage under these conditions for at least 10 years without significant changes in germination has been established. The importance of meteorological conditions in the formation and ripening of seeds for their longevity is confirmed. The relationship between the decrease of barley seeds longevity and storage conditions, amount of rainfall, temperature regime during the growing season of plants is discussed.

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