scholarly journals Viscosity of set-style yogurt as influenced by heat treatment of milk and added demineralized whey powder

2002 ◽  
Vol 47 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Jelena Djurdjevic-Denin ◽  
Ognjen Macej ◽  
Snezana Jovanovic
Keyword(s):  
Heat Treatment ◽  
Milk Powder ◽  
Skim Milk ◽  
Matter Content ◽  
Lactobacillus Delbrueckii ◽  
Dry Matter Content ◽  
90 C 10 ◽  
Milk Samples ◽  
Whey Powder ◽  
Heat Treated

Skim milk powder was reconstituted to obtain milk A (with 8.44% TS). Milk sample A was standardized with different amounts of demineralized whey powder (DWP) to obtain milk B (with 9.71% TS) and milk C (with 10.75% TS). Milk samples were heat treated at 85?C/20 min and 90?C/10 min, respectively. Untreated milk was used as control. Milk samples were inoculated with 2.5% of commercial yogurt culture (containing Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the ratio 1:1) at 43?C. Samples were incubated until pH 4.6 was reached. Samples were immediately cooled to 4?C and held at that temperature until analyses. Measurements of viscosity were done with Brookfield DV-E Viscometer. Spindle No 3 at 20 rpm was used for all samples. After 1 day of storage, set-style yogurt samples produced from untreated milk had the highest, while samples produced from milk heat treated at 90?C/10 min the smallest initial viscosity, regadless of the dry matter content and composition. Average viscosity of set-style yogurts decreased with intensifying temperature of applied heat-treatment. During storage, set-style yogurt samples produced from milk heat treated at 90?C/10 min had the least pronounced decrease of viscosity during shearing. After 14 days of storage, set-style yogurt samples produced from milk standardized with demineralized whey powder had higher viscosity than samples produced from basis milk.

scholarly journals The influence of dry matter, applied heat treatment and storage period on the viscosity of stirred yogurt

2002 ◽  
Vol 47 (2) ◽  
pp. 189-204 ◽  
Author(s):  
Jelena Denin-Djurdjevic ◽  
Ognjen Macej ◽  
Snezana Jovanovic
Keyword(s):  
Heat Treatment ◽  
Dry Matter ◽  
Milk Powder ◽  
Skim Milk ◽  
Storage Period ◽  
Matter Content ◽  
Lactobacillus Delbrueckii ◽  
Dry Matter Content ◽  
90 C 10 ◽  
Heat Treated

Skim milk powder reconstituted to 8.44% TS, 9.65% TS and 10.84% TS respectively was used for investigation. Untreated milk and milk heat treated at 85?C/20 min and 90?C/10 min, respectively, were used for the investigation. Milk was inoculated with 2.5% of yogurt culture (containing Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the ratio 1:1) at 43?C. Samples were incubated until pH 4.6 was reached. Samples were immediately cooled to 4?C and held at that temperature during 14 days. Acid casein gel was stirred after 1, 7 and 14 days of storage. Measurements were done at 30 rpm during 2 min, at 20?C. According to the investigation, it could be concluded that both applied heat treatment and dry matter content influence viscosity of stirred yogurt. Viscosity increases when dry matter content increases. The smallest viscosity had yogurt produced from untreated milk with 8.44% TS, while samples produced from milk with 10.84% TS had the highest viscosity. Applied heat treatments had significant influence on viscosity of yogurt gained by stirring of acid casein gels after 7 and 14 days of storage. Stirred yogurt produced from milk heat treated at 90?C/10 min had a higher viscosity than samples produced from milk heat treated at 85?C/20 min. Storage period influenced average viscosity of stirred yogurt. Samples of stirred yogurt produced from milk with 8.44% TS showed a decrease of average viscosity during storage regardless of the applied heat treatment of milk. The highest average viscosity had samples produced from milk with 10.84% TS.

scholarly journals The influence of investigated factors on viscosity of stirred yogurt

2002 ◽  
Vol 47 (2) ◽  
pp. 219-231 ◽  
Author(s):  
Jelena Denin-Djurdjevic ◽  
Ognjen Macej ◽  
Snezana Jovanovic
Keyword(s):  
Milk Sample ◽  
Skim Milk ◽  
Streptococcus Thermophilus ◽  
Matter Content ◽  
Lactobacillus Delbrueckii ◽  
Dry Matter Content ◽  
90 C 10 ◽  
Milk Samples ◽  
Heat Treated ◽  
Control Milk

Skim milk was reconstituted to obtain milk with 8.44% DM, which was standardized with demineralized whey powder (DWP) to obtain milk sample A (9.71% DM) and milk sample B (10.75% DM). Milk samples were heat treated at 85?C/20 min and 90?C/10 min, respectively. Untreated milk was used as control. Milk samples were inoculated with 2.5% of commercial yogurt culture (containing Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the ratio 1:1) at 43?C. Samples were incubated until pH 4.6 was reached. Samples were immediately cooled to 4?C and held at that temperature until analyses. Samples of acid casein gels were stirred after 1, 7 and 14 days of storage. Measurements of viscosity were done with Brookfield DV-E Viscometer. Spindle No 3 at 30 rpm was used for all samples. Duration of fermentation decreased when DWP was used for standardization of milk dry matter content. Yogurt samples produced from milk heat treated at 85?C/20 min, obtained by stirring of gel 1 day after production had a higher viscosity than sample produced from milk heat treated at 90?C/10 min. On the other hand, samples produced from milk heat treated at 90?C/10 min had a greater viscosity after 7 and 14 days of storage, which indicates a greater hydrophilic properties and a more pronounced swelling of casein micelles.

scholarly journals The influence of applied heat treatments on whey protein denaturation

2002 ◽  
Vol 47 (2) ◽  
pp. 205-218
Author(s):  
Safet Fetahagic ◽  
Ognjen Macej ◽  
Jelena Denin-Djurdjevic ◽  
Snezana Jovanovic
Keyword(s):  
Heat Treatment ◽  
Whey Protein ◽  
Protein Denaturation ◽  
Skim Milk ◽  
Heat Treatments ◽  
Matter Content ◽  
90 C 10 ◽  
Milk Samples ◽  
Heat Treated ◽  
Sera Samples

Reconstituted skim milk with 8.01% DM was standardized with 3% skim milk powder and with 3% demineralized whey powder (DWP), respectively. Gained milk samples are named as 8%, 11% and 8%+3%DWP. All samples were heat treated at 85?C/10 min, 90?C/10 min and 95?C/10 min, respectively. Untreated milk was used as control. Milk samples were coagulated by glucono-d-lactone (GDL) at the temperature of 45?C until pH 4.60 was reached. Milk nitrogen matter content decreased during heat treatments, but linear relationship between applied heat treatments and nitrogen matter decreasing was not found. Nitrogen matter content of sera gained from both untreated and heat treated milk increased with the increase of milk dry matter content and with the addition of DWP. The higher temperature of applied heat treatment, the smaller sera nitrogen matter content. Nitrogen matter content in sera obtained from untreated milk were 64.90 mg%, 96.80 mg% and 117.3 mg% for milk 8%, 11% and 8%+3.0% DWP, respectively. Sera samples obtained from milk 8% heat treated at 85?C/10 min, 90?C/10 min and 95?C/10 min had 38.70 mg% 38.30 mg% and 37.20 mg% of nitrogen matter, respectively. Sera samples obtained from milk 11% heat treated at 85?C/10 min, 90?C/10 min and 95?C/10 min had 55.90 mg%, 52.80 mg% and 51.30 mg% of nitrogen matter, respectively. Sera samples obtained from milk 8% heat treated at 85?C/10 min, 90?C/10 min and 95?C/10 min had 69.50 mg%, 66.20 mg% and 66.00 mg% of nitrogen matter respectively. Distribution of nitrogen matter from untreated milk to milk sera were 12.01%, 11.14% and 17.69% for milk 8%, 11% and 8%+3.0% DWP respectively. Distribution of nitrogen matter from milk 8% heat treated at 85?C/10 min, 90?C/10 min and 95?C/10 min to sera samples were 6.99%, 6.72% and 6.59%, respectively. Distribution of nitrogen matter from milk 11% heat treated at 85?C/10 min, 90?C/10 min and 95?C/10 min to sera samples, were 6.02%, 5.32% and 5.21%, respectively. Distribution of nitrogen matter from milk 8%+3%DWP heat treated at 85?C/10 min, 90?C/10 min and 95?C/10 min to sera samples were 9.64%, 8.66% and 8.67%, respectively. Whey protein denaturation increased with increasing of the temperature of the applied heat treatment. Denaturation was the most significant for milk sample 11%.

scholarly journals The influence of GDL concentration on milk pH change during acid coagulation

2002 ◽  
Vol 47 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Safet Fetahagic ◽  
Ognjen Macej ◽  
Jelena Denin-Djurdjevic ◽  
Snezana Jovanovic
Keyword(s):  
Buffer Capacity ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
90 C 10 ◽  
Ph Change ◽  
Protein Ratio ◽  
Milk Samples ◽  
Ph Values ◽  
Heat Treated

Skim milk powder was reconstituted to obtain milk A (with 8.01% TS). Milk A was standardized with 3% of skim milk powder and 3% of demineralized whey powder (DWP), respectively, to obtain milk B (with 11.15% TS) and milk C (with 11.10% TS). Milk samples were heat treated at 85?C/10 min, 90?C/10 min and 95?C/10 min, respectively. Untreated milk was used as control. Acidification was carried out at 25?C, 35?C and 45?C during 240 min with GDL (glucono-d-lactone), namely with the amount of 0.5%, 0.75%, 1.0%, 1.25% 1.5%, 1.75%, 2.0% and 3.0% of GDL, respectively. The results showed that all investigated factors, explicitly GDL concentration, acidification temperature and applied heat treatment of milk as well as added DWP influence the change of pH during acidification. Milk samples standardized with DWP had smaller buffer capacity and faster change of pH than samples standardized with skim milk powder. Only at acidification temperature of 25?C, added DWP did not influence the change of milk buffer capacity regardless of the change of casein:whey protein ratio. Under this acidification condition, both milk samples standardized with skim milk powder and DWP had similar final pH values.

OBSERVATIONS ON DIGESTION IN THE PIG USING A RE-ENTRANT INTESTINAL FISTULA

1963 ◽  
Vol 43 (2) ◽  
pp. 215-225 ◽  
Author(s):  
H. M. Cunningham ◽  
D. W. Friend ◽  
J. W. G. Nicholson
Keyword(s):  
Dry Matter ◽  
Corn Starch ◽  
Corn Oil ◽  
Potato Starch ◽  
Milk Powder ◽  
Skim Milk ◽  
Matter Content ◽  
Soluble Carbohydrates ◽  
Intestinal Fistula ◽  
Dry Matter Content

Sixty-four 12- to 24-hour collections were made of digesta flowing from re-entrant ileal fistulas of two pigs used to study the digestibility and rate of passage of various materials in the proximal digestive tract. An average of 88 per cent of the digestible dry matter and 91 per cent of the digestible protein of a 20 per cent protein ration was digested in the stomach and small intestine. The ration was very finely ground and fed only for short periods. The dry matter content of the fistula digesta was considerably higher when the concentrate ration was fed than when dried skim milk powder or various soluble carbohydrates were fed. Glucose was the most completely digested of all carbohydrates tested, usually followed in decreasing order by corn starch, galactose, sucrose, lactose and potato starch. Undigested soluble carbohydrates were accompanied by large volumes of fluid which seldom exceeded isotonic concentrations. Undigested potato starch resulted in digesta which at times contained 42 per cent dry matter. Fats fed with dried skim milk were well digested with maximum digestion coefficients of 91 recorded for corn oil and 84 for tallow. There were few changes in the composition of the digesta flowing from the fistula at various times of the day but there was a significant increase (P <.01) in the protein and ash content from the first to second 6-hour interval after feeding dried skim milk.

scholarly journals Influence of selected factors on the viscosity of set style yogurt and acid casein gel at constant speed of spindle rotation

2004 ◽  
Vol 49 (2) ◽  
pp. 233-250 ◽  
Author(s):  
Safet Fetahagic ◽  
Jelena Denin-Djurdjevic ◽  
Snezana Jovanovic ◽  
Ognjen Macej
Keyword(s):  
Linear Relationship ◽  
Dry Matter ◽  
Heat Treatments ◽  
Matter Content ◽  
Constant Speed ◽  
Dry Matter Content ◽  
Milk Samples ◽  
Heat Treated ◽  
Spindle Rotation

The influence of milk dry matter (DM) content (8.20%, 9.27% and 10.28%) and applied heat treatments (untreated milk and milk heat-treated at 90oC/10?) on the viscosity of set-style yogurt and acid casein gel gained by acidification with GDL (glucono-d-lactone) has been investigated. Viscosity was measured during the time of 3 minutes at constant speed of spindle rotation of 20 rpm. The results have shown that yogurt samples produced from untreated milk had higher viscosity values than samples produced from heat-treated milk. An increase of dry matter content influenced the increase of viscosity of yogurt samples produced from both untreated milk and heat-treated milk. Samples with 10.28% DM had the highest viscosity values. An increase of DM content in samples of acid casein gel produced by acidification with GDL had an opposite influence. The samples with smallest DM content had the highest viscosity values. There is no linear relationship between the period of storage of set-style yogurt produced from heat-treated milk and viscosity value.

scholarly journals Staphylococcal Food Poisoning Associated with Spray-Dried Milk

1955 ◽  
Vol 53 (4) ◽  
pp. 387-397 ◽  
Author(s):  
P. H. R. Anderson ◽  
Doris M. Stone
Keyword(s):  
Spray Drying ◽  
Clinical Features ◽  
Milk Powder ◽  
Food Poisoning ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Large Numbers ◽  
Heat Treated ◽  
Drying Chamber ◽  
Spray Dried

SummaryEight explosive outbreaks of food poisoning, occurring in school canteens in England during 1953 and affecting 1190 known cases, are described. The clinical features were characteristic of the toxin type of illness. No deaths occurred.The food causing all of these outbreaks was prepared from spray-dried skim milk powder. It was not subsequently heat-treated and was usually consumed 3–4 hr. after preparation.The spray-dried milk powder proved to contain a high content of bacteria, including large numbers of Staph. aureus, of a phage pattern often associated with food poisoning. The assumption was therefore made that these outbreaks were caused by staphylococcal enterotoxin.Because the food was often consumed within 3–4 hr. of reconstitution of the milk powder—before, in fact, the staphylococci had had time to grow—it is concluded that the poisoning must have been due mainly to pre-formed toxin.Consideration is given to the opportunities for the formation of toxin in a spray-drying plant, and reasons are brought forward for believing that it is formed mainly in the balance tank where the warm milk is kept, sometimes for several hours, before passing into the final drying chamber.The processing of the milk and the precautions for preventing contamination of the finished product are discussed.

scholarly journals ANALYSIS OF MILK QUALITY, ADULTERATION AND MASTISIS IN FOUR DIFFERENT MILK SAMPLES

2016 ◽  
Vol 3 (1) ◽  
pp. 67-69
Author(s):  
Sudhasaravanan R ◽  
Binukumari S
Keyword(s):  
Nutritive Value ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Milk Quality ◽  
Milk Samples ◽  
Appearance Quality ◽  
Health Related ◽  
Yellowish White ◽  
Better Than

The present study is aimed to analyze the milk quality, adulteration and mastitis infection in milk Samples available in market. Four different milk samples were analyzed for physical appearance, quality, adulterants and mastitis infection. 90% milk samples were white in color and 10 % were yellowish white. pH ranged between 6.5 – 6.9. Analysis of milk quality showed that Arokya milk appears to be better than the other three milk samples. Out of 4 milk samples analyzed for adulteration, adulterants found were glucose (80%), skim milk powder (58%), salt (51%) and urea (35%) while found negative for formalin, salicylic acid, boric acid, starch, soap and ammonium sulphate. All the samples were free from mastitis infection. The adulterants decrease the nutritive value of milk and may also cause serious human health related problems.

Inhibition of the Antibacterial Lactoperoxidase-Thiocyanate-Hydrogen Peroxide System by Heat-Treated Milk

1985 ◽  
Vol 48 (6) ◽  
pp. 494-498 ◽  
Author(s):  
B. EKSTRAND ◽  
W. M. A. MULLAN ◽  
A. WATERHOUSE
Keyword(s):  
Heat Treatment ◽  
Hydrogen Peroxide ◽  
Skim Milk ◽  
Inhibitory Effect ◽  
Sulfhydryl Groups ◽  
Inhibitory Factor ◽  
Casein Micelle ◽  
Heated Milk ◽  
Heat Treated

The antibacterial system, lactoperoxidase-H2O2-SCN− was affected by the presence of heated milk or skim milk reconstituted from powders having received severe heat treatment. This inhibitory effect was related to the increase in exposed sulfhydryl groups and to the redistribution of protein between micellar and whey phases. Chromatographic analyses of heat-treated milk showed that the inhibitory factor was associated with the casein micelle fraction. The inhibition, however, was overcome by addition of unheated skim milk.

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