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

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.

2002 ◽  
Vol 47 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Jelena Djurdjevic-Denin ◽  
Ognjen Macej ◽  
Snezana Jovanovic

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.


2002 ◽  
Vol 47 (2) ◽  
pp. 219-231 ◽  
Author(s):  
Jelena Denin-Djurdjevic ◽  
Ognjen Macej ◽  
Snezana Jovanovic

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.


2021 ◽  
Vol 3 (1) ◽  
pp. 18-22
Author(s):  
M. Pagthinathan ◽  
A.P. A. S. Gunasekara

Non-meat ingredients are used to impart flavor, slow bacterial growth, and increase the yield of the sausage production. To study the quality of chicken sausage incorporated with non-meat ingredients namely, soy protein powder, non-fat milk powder and potato starch at the rate of 2% (w/w) concentration. Sausage samples were analyzed for physical, nutritional, and sensory properties during refrigerated storage at -4 ℃. The nutritional, physical and sensory characteristics were analyzed, at day 1, week 1, week 2 and week 3 of storage. Moisture, ash, dry matter, fat, pH, texture, and color were significantly difference (p<0.05) among the treatments at day one. During storage the ash, pH content and dry matter content were significantly (p<0.05) increased, and fat content and moisture content was significantly (p<0.05) decreased storage period. At week one, the higher hardness value showed in soy protein powder incorporated chicken sausage and least value showed in without added non-meat ingredient (control) sausage. As results of organoleptic characteristics revealed that, 2% of potato starch incorporated chicken sausage had the highest mean score of overall quality of all sensorial properties namely, color, taste, texture, flavor, and overall acceptability.


1963 ◽  
Vol 43 (2) ◽  
pp. 215-225 ◽  
Author(s):  
H. M. Cunningham ◽  
D. W. Friend ◽  
J. W. G. Nicholson

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.


2002 ◽  
Vol 47 (2) ◽  
pp. 205-218
Author(s):  
Safet Fetahagic ◽  
Ognjen Macej ◽  
Jelena Denin-Djurdjevic ◽  
Snezana Jovanovic

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%.


2014 ◽  
Vol 43 (3) ◽  
pp. 202-206
Author(s):  
RC Biswas ◽  
S Akhter ◽  
MM Hossain ◽  
MS Rana ◽  
M Habibullah

The experiment was conducted to examine the effect of freezing and defrosting methods on the quality of beef. Two types of beef samples named as fresh and cured beef samples were taken. Both types were divided into three sub divisions namely air, water and microwave oven. These samples were stored at -20°C temperature in the freezer for 90 days and analyzed on 10th, 45th and 90th day. The dry matter, crude protein, ether extract and ash percentages and standard plate count (SPC) were differed significantly (p<0.01) among the air, water and microwave defrosted samples. Up to 90th days of freezing at -200C dry matter content increased with the increase of storage time almost in all samples except microwave fresh samples. The protein content decreased with the increase of storage time from 10 to 45 days but increased from 45 to 90 days. The ash content decreased with the increase of storage time in case of fresh frozen samples but increased with the increase of storage time in case of cured frozen samples except microwave oven cured sample. Ether extract value gradually increased with the increasing of storage period in case of air fresh, water fresh, air cured and water cured frozen samples but decreased with the increasing of storage period in case of microwave oven fresh and microwave oven cured samples. The SPC value increased with the increase of storage time in case of all samples and differed significantly (p<0.01) among the parameters. The cured microwave defrosted beef was proved as the best technique of defrosting frozen beef.DOI: http://dx.doi.org/10.3329/bjas.v43i3.21649 Bang. J. Anim. Sci. 2014. 43 (3): 202-206


1976 ◽  
Vol 56 (2) ◽  
pp. 327-333 ◽  
Author(s):  
E. E. LISTER ◽  
D. B. EMMONS

Three spray-dried powders were prepared after heating skim milk for 30 min at 60 C (LT), 73.9 C (MT) or 85 C (HT). Each was reconstituted to two concentrations of dietary fat and fed to five or six calves for 26 days after purchase at approximately 1 wk of age. Calves receiving the HT skim milk had significantly (P < 0.05) higher incidence of diarrhea and slower rate of gain over 19 days on test as compared with those fed the MT and LT skim milks. Subsequently growth rate was unaffected by the skim milk source and there were interactions of fat level with skim milk source. The high fat level (22.2% of dietary dry matter) resulted in a higher incidence of alopecia than in calves receiving the low fat level (16.2% of dietary dry matter). Nutrient digestibilities and nitrogen balance, measured from day 20 to day 26, were unaffected by skim milk treatments or fat concentrations. This experiment indicated that young calves, less than 3 wk of age, require a diet based on skim milk that has not been severely heat-treated and the curd formation is a suitable index of quality for such milk replacer diets. Where control diets for milk-replacer studies are designated "all milk protein," it is important for correct interpretation to define their curd-forming characteristics. For older calves, coagulation appears not to be a requirement.


1997 ◽  
Vol 6 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Tuomo Tupasela ◽  
Petri Koskela ◽  
Eero Pahkala ◽  
Veikko Kankare

Whey proteins, which are mainly composed of β-lactoglobulin (β-lg) and α-lactalbumin (α-la), account for about 20% of the proteins of bovine milk. In this study we investigated the effect of pH, dry matter content, concentration factor, heat treatment and centrifugation on the separation of α-la from β-lg using clarified whey as raw material, α-La precipitation was highest, 23.3%, when the dry matter content ranged from 5.8% to 25.7%. The optimum pH of α-la precipitation depended on the dry matter content. The separation efficiency increased when the concentration factor and heat treatment time at 55°C increased. A longer centrifugation time and higher separation speed did not have a marked effect on the separation efficiency. Separation was more efficient with a higher centrifugation speed at concentration levels 30 X and 60 X. The separation efficiency did not improve when the temperature was raised from 55°C to 65°C but it was better at a concentration level 120 X than at 60 X and 30 X, and also at concentration level 60 X than with 30 X.


2018 ◽  
Vol 11 (1) ◽  
pp. 30 ◽  
Author(s):  
Kiatkamjon Intani ◽  
Sajid Latif ◽  
Md. Islam ◽  
Joachim Müller

Biochar from crop residues such as corncobs can be used for soil amendment, but its negative effects have also been reported. This study aims to evaluate the phytotoxic effects of different biochar treatments and application rates on cress (Lepidium sativum). Corncob biochar was produced via slow pyrolysis without using purging gas. Biochar treatments included fresh biochar (FB), dried biochar (DB), washed biochar (WB), and biochar water extract (WE). Biochar application rates of 10, 20, and 30 t/ha were investigated. Significant phytotoxic effects of biochar were observed on germination rates, shoot length, fresh weight, and dry matter content, while severe toxic effects were identified in FB and WE treatments. Germination rate after 48 h (GR48) decreased with the increase of biochar application rates in all treatments. The observed order of performance of the biochar treatments for germination, shoot length, and shoot fresh weight for every biochar application rate was WB>DB>WE>FB, while it was the reverse order for the shoot dry matter content. WB treatment showed the best performance in reducing the phytotoxicity of biochar. The mitigation of the phytotoxicity in fresh corncob biochar by washing and heat treatment was found to be a simple and effective method.


2017 ◽  
Vol 45 (2) ◽  
pp. 507-516 ◽  
Author(s):  
Sándor RÓZSA ◽  
Tincuța-Marta GOCAN ◽  
Vasile LAZĂR ◽  
Ileana ANDREICA ◽  
Melinda RÓZSA ◽  
...  

Agaricus spp. mushrooms are edible fungi of commercial and medicinal importance. Mushrooms convert nutritionally valueless substances into proteinous food with a very efficient bioconversion. Consumption of mushrooms, has increased substantially due to their delicacy, flavour, nutritional and medicinal value, being considered an excellent source of protein, which can contribute to the formulation of a balanced diet. Three species of Agaricus spp. mushrooms were used in this study: Agaricus campestris (L. ex Fr.), Agaricus bisporus (J.E. Lange) and Agaricus blazei (Murrill). This study aims to examine the effects of blanching, soaking and manufacturing processes (sun drying, oven drying and canning) on some chemical constituents of mushrooms (soluble dry matter, protein and total sugars). The analyses were performed initially at conservation and they were repeated after 6, 12 and 18 months of preservation. Since all treatments caused reduction of the dry matter content, it can be concluded that the smallest decrease during the storage period was recorded by soaked and sun dried A. blazei (1.6 g 100 g-1 FM). The maximum soluble dry matter loss was recorded at blanched and canned A. bisporus (2.8 g 100 g-1 FM). Blanching treatment of preheated (sun dried and oven dried) samples, after storage period, led the protein content to slightly decrease, between 0.4 g 100 g-1 DM and 0.8 g 100 g-1 DM. The smallest decrease of total sugars during the storage period was registered by canned, untreated A. campestris with 1.2 g 100 g-1 DM and the largest decrease was registered by blanched oven dried A. blazei with 2.9 g 100 g-1 DM.


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