Cooling curve in production sweetened concentrated milk supplemented with whey: Influence on the size and microstructure of lactose crystals

2019 ◽  
Vol 25 (6) ◽  
pp. 451-461
Author(s):  
IT Smykov ◽  
AI Gnezdilova ◽  
YuV Vinogradova ◽  
AV Muzykantova ◽  
AK Lyamina

The aim of this work was to develop a methodology to calculate the cooling curve for the sweetened condensed milk with added whey powder production and to assess the cooling regime effect on the distribution of lactose crystals’ size and their microstructure. It is proposed to use a two-stage cooling curve. At the first stage, the cooling is carried out at a high speed, and at the second with a speed that varies depending on the rate of lactose crystallization. Electron microscopic studies have confirmed the cooling regime effect on the crystals’ microstructure. The practical use of the developed regime showed that the two-stage cooling regime allows to reduce the size of lactose crystals (P < 0.05) and improve the quality of the finished product.

1981 ◽  
Vol 29 (12) ◽  
pp. 1397-1404 ◽  
Author(s):  
P Ordronneau ◽  
P B Lindström ◽  
P Petrusz

Four unlabeled antibody immunocytochemical techniques, the "single bridge" (Avrameas S: Immunocytochemistry 6:825, 1969; Mason TE, Phifer RF, Spicer SS, Swallow RS, Dreskin RD: J Histochem Cytochem 17:190, 1969a; Sternberger LA, Cuculis JJ: 1969), the "single peroxidase-antiperoxidase (PAP)" (Sternberger LA, Hardy PH Jr, Cuculis JJ, Meyer HG: J Histochem Cytochem 18:315, 1970), the "double PAP" (Vacca LL, Rosario SL, Zimmerman EA, Tomashefsky P, Ng P-Y, Hsu KC: J Histochem Cytochem 23:208, 1975) and the "double bridge" (Ordronneau P, Petrusz P: Am J Anat 158:491, 1980) were compared at both the light and electron microscopic levels. The "double" procedures involved repeating incubations with the bridge antibody, in this case, sheep anti-rabbit gamma globulin, followed either by a second PAP step for the "double PAP" or a second anti-horseradish peroxidase step and a single incubation in horseradish peroxidase for the "double bridge." At both the light and electron microscopic levels the staining intensity was greater with the "double" techniques than with the "single" ones. This is probably due to amplification achieved with the second sheep anti-rabbit gamma globulin step, permitting an increase in the number of horseradish peroxidase molecules bound for each molecule of tissue-bound primary antibody. Also, the quality of the various commercial PAP preparations tested was variable. With the weaker ones the staining intensity could be increased by performing an incubation in fresh horseradish peroxidase after the PAP step. Finally, in electron microscopic studies, the reaction products formed in both the bridge and PAP procedures were identical in shape and size.


1970 ◽  
Vol 42 (2) ◽  
pp. 147-156 ◽  
Author(s):  
M Asaduzzaman ◽  
KY Miah ◽  
AKMA Mannan ◽  
ME Haque ◽  
A Ara ◽  
...  

To assess the quality of sweetened condensed milk of Bangladesh four different brands of sweetened condensed milk were selected viz. Danish, Fresh milk, Star ship and Goalini. Twenty samples were analyzed for physical (organoleptic), chemical and microbiological qualities. From the physical test it was observed that all samples were in good grade i.e. fresh, free from odour, viscous and smooth, rich cream to yellow in colour and very sweet in taste. The average physical score was 88.05±7.631. Sweetened condensed milk had a titrable acidity of 0.135 to 0.180 %; fat 6.80 to 8.0 %; protein 6.51 to 7.96 %; ash 1.50 to 1.83 %; carbohydrate 53.74 to 55.62 % and total solids (TS) 69.98 to 73.15 %. The total viable count was in the range of 10x102 to 20x102 CUF/g; no coliform bacteria were found. The results of acidity percentage, fat content, organoleptic tests and microbiological tests indicated that there was no variation among different brands of sweetened condensed milk. But, when other chemical parameters (protein, ash, carbohydrate and total solids) were considered then Star ship was found to be better than that of Danish, Goalini and Fresh milk. Bangladesh J. Sci. Ind. Res. 42(2), 147-156, 2007


2018 ◽  
Vol 4 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Om Prakash Chauhan ◽  
Shima Shayanfar ◽  
Stefan Topefl

ABSTRACTEffect of pulsed electric field as a blanching pretreatment on cell permeabilization, microstructure and quality of dehydrated apple slices was studied. Apple slices were pulsed electric field pretreated (1.0, 1.5 and 2.0 kV/cm using 25 and 75 pulses) at a temperature of 60 and 80°C in water followed by dehydration at 60°C in a cabinet dryer. Cell disintegration index was found to increase significantly (p<0.05) with increase in the electric field strength, number of pulses and blanching temperature and thereby reducing the drying time. The dehydrated slices showed lower hardness and higher lightness (L*) values for the samples treated at higher electric field strength for longer durations. Scanning electron microscopic studies of samples revealed better retention of cellular integrity when pre-treated at a low level of PEF (1.0 kV/cm using 25 pulses) and blanched at low temperature (60°C). However, the samples treated to a level of 1.5 kV/cm and 75 pulses of PEF with subsequent blanching temperature 80°C was found to yield optimum cell permeabilization. The study suggests that PEF can be used as an effective blanching pretreatment for achieve good quality dehydrated apple slices in less drying time. 


Author(s):  
Jan Zarzycki ◽  
Joseph Szroeder

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.


Author(s):  
G. Lehmpfuhl

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.


Author(s):  
F. G. Zaki ◽  
E. Detzi ◽  
C. H. Keysser

This study represents the first in a series of investigations carried out to elucidate the mechanism(s) of early hepatocellular damage induced by drugs and other related compounds. During screening tests of CNS-active compounds in rats, it has been found that daily oral administration of one of these compounds at a dose level of 40 mg. per kg. of body weight induced diffuse massive hepatic necrosis within 7 weeks in Charles River Sprague Dawley rats of both sexes. Partial hepatectomy enhanced the development of this peculiar type of necrosis (3 weeks instead of 7) while treatment with phenobarbital prior to the administration of the drug delayed the appearance of necrosis but did not reduce its severity.Electron microscopic studies revealed that early development of this liver injury (2 days after the administration of the drug) appeared in the form of small dark osmiophilic vesicles located around the bile canaliculi of all hepatocytes (Fig. 1). These structures differed from the regular microbodies or the pericanalicular multivesicular bodies. They first appeared regularly rounded with electron dense matrix bound with a single membrane. After one week on the drug, these vesicles appeared vacuolated and resembled autophagosomes which soon developed whorls of concentric lamellae or cisterns characteristic of lysosomes (Fig. 2). These lysosomes were found, later on, scattered all over the hepatocytes.


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