scholarly journals Changes in Particle Size, Sedimentation, and Protein Microstructure of Ultra-High-Temperature Skim Milk Considering Plasmin Concentration and Storage Temperature

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2339
Author(s):  
So-Yul Yun ◽  
Jee-Young Imm

Age gelation is a major quality defect in ultra-high-temperature (UHT) pasteurized milk during extended storage. Changes in plasmin (PL)-induced sedimentation were investigated during storage (23 °C and 37 °C, four weeks) of UHT skim milk treated with PL (2.5, 10, and 15 U/L). The increase in particle size and broadening of the particle size distribution of samples during storage were dependent on the PL concentration, storage period, and storage temperature. Sediment analysis indicated that elevated storage temperature accelerated protein sedimentation. The initial PL concentration was positively correlated with the amount of protein sediment in samples stored at 23 °C for four weeks (r = 0.615; p < 0.01), whereas this correlation was negative in samples stored at 37 °C for the same time (r = −0.358; p < 0.01) due to extensive proteolysis. SDS-PAGE revealed that whey proteins remained soluble over storage at 23 °C for four weeks, but they mostly disappeared from the soluble phase of PL-added samples after two weeks’ storage at 37 °C. Transmission electron micrographs of PL-containing UHT skim milk during storage at different temperatures supported the trend of sediment analysis well. Based on the Fourier transform infrared spectra of UHT skim milk stored at 23 °C for three weeks, PL-induced particle size enlargement was due to protein aggregation and the formation of intermolecular β-sheet structures, which contributed to casein destabilization, leading to sediment formation.

1998 ◽  
Vol 8 (4) ◽  
pp. 311-318 ◽  
Author(s):  
David J. Oldfield ◽  
Harjinder Singh ◽  
Michael W. Taylor ◽  
Kevin N. Pearce

1980 ◽  
Vol 43 (5) ◽  
pp. 392-394 ◽  
Author(s):  
R. S. MEHTA ◽  
R. BASSETTE

Ultra-high-temperature sterilized milk packaged in aluminum foil-lined or plain polyethylene-lined cartons was stored 1.5 months at 4 C in the dark or 22 C under fluorescent light. Five trained judges found milk at 4 C was not as stale and thus had a more acceptable flavor than milk at 22 C. Flavor of milk in aluminum foil-lined cartons was not as good as freshly pasteurized milk, but superior to milk in polyethylene-lined cartons. Increases in off-flavor intensity paralleled increases in concentrations of n-pentanal and an unidentified neutral volatile compound. A 24-member, untrained consumer taste-panel preferred the flavor of freshly pasteurized milk to 3-month-old commercial or 6-month-old experimental ultra-high-temperature sterilized milks in aluminum foil-lined cartons, which in turn were preferred over 6-month-old experimental ultra-high-temperature sterilized milk in polyethylene-lined cartons.


2021 ◽  
Vol 8 (1) ◽  
pp. 37
Author(s):  
Elsera Br Tarigan ◽  
Edi Wardiana ◽  
Handi Supriadi

<p><em>Coffee is a beverage that is widely consumed around the world. Proper packaging and storage temperature may extend shelf life of ground coffee. The study aimed to analyze the shelf life of ground Arabica coffee stored in different packaging types and temperature, conducted at smallholder coffee plantations in Garut Regency and the Integrated Laboratory of Indonesian Industrial and Beverage Crops Research Institute, Sukabumi, from June to August 2018. A completely randomized design in factorial was used with 3 factors and 2 replications. The first factor was the packaging type  which consisted of 3 types: thick alumunium  foil 65</em><em>m</em><em> (AF65), thick alumunium  foil 130</em><em>m</em><em> (AF130), and thick lamination 114</em><em>m</em><em> (L144). The second factor was the storage temperature which consisted of 3 levels: 25 <sup>o</sup>C, 35 <sup>o</sup>C, and 45 <sup>o</sup>C, while the third factor was the storage period which consisted of 5 levels: coffee unstored, and coffee stored for 2 weeks, 4 weeks, 6 weeks, and 8 weeks. The variables observed were the water and fat content, and the analysis of shelf life was carried out using the ASLT (Accelerated Shelf Life Test) method. The results showed that during storage, the water content increased, whereas the fat content decreased. Fat content is a critical variable in determining the shelf life of coffee. The coffee in AF130 packaging has longer shelf life than in AF65 and L144. To extend the shelf life of coffee packaged in AF130 and L144 is best kept at 45<sup> o</sup>C whereas coffee in AF65 packaging  is ideally at 25<sup> o</sup>C.</em></p>


1991 ◽  
Vol 54 (2) ◽  
pp. 109-112 ◽  
Author(s):  
R.K. HUTCHENS ◽  
A.P. HANSEN

Raw cream was standardized to 10% fat and processed by ultra-high-temperature (UHT) steam injection at 149°C for 20 s, 149°C for 3.4 s, 138°C for 20 s, and 143°C for 7 s, then aseptically packaged by a Tetra Pak AB3-250 filler. Packages were stored for 12 months at 24°C and analyzed at 0, 1, 3, 6, and 12 months. Fat-soluble carbonyls were extracted from the UHT cream with carbonyl-free hexanes and converted to their 2,4-dinitrophenyl-hydrazone derivatives. Alkanal hydrazones were separated by column chromatography into pure fractions. Spectrophotometry and gas chromatography were used to identify the alkanals. Butanal, hexanal, heptanal, nonanal, and decanal were identified and found to decrease in concentration during storage.


2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4493
Author(s):  
Ronan Maciel Marcos ◽  
Giovano Neumann ◽  
Cesar Pereira Rebechi de Toledo ◽  
João Marcos Sena ◽  
Gilmar Baumgartner ◽  
...  

<p>This study describes the seminal and spermatic characteristics of fresh semen of <em>Steindachneridion melanodermatum </em>and investigates the effects of dilution, temperature, and storage period on its spermatic parameters. Sperm samples were collected from nine hormonally-induced males. The following parameters in fresh sperm were analyzed: seminal plasma osmolality (OSM), seminal pH, sperm motility (MOT), sperm velocity (SV) (including sperm curvilinear velocity (CVV), sperm straight-line velocity (SLV), and sperm average path velocity (APV)), total time of sperm motility (TEMP), sperm concentration (CONC), and index of sperm normality (NORM). Sperm samples from each male were diluted in a solution containing 5% fructose and 5% powdered milk, and stored at 10°C and 25°C. The same was carried out for sperm samples not subjected to dilution. From these samples, MOT, CVV, SLV, APV, SV, and TEMP were measured after 0 h, 5 h, 9 h, 18 h, 27 h, 36 h, 45 h, and 54 h. Males released 11.74 ± 5.38 mL of sperm, with an osmolality of 258.78 ± 29.36 mOsm.kg-1 and pH of 7.11 ± 0.31. The sperm presented a MOT of 99.86 ± 0.31% at a concentration of 1.03 × 1010 ± 3.65 × 109 spermatozoa.mL-1 with CVV of 185.58 ± 14.11 ?m.s-1, SLV of 49.15 ± 4.66 ?m.s-1, APV of 87.02 ± 4.13 ?m.s-1, SV of 106.52 ± 4.45 ?m.s-1, TEMP of 79.31 ± 5.62 s, NORM of 75.81 ± 5.71%. The results indicate that sperm motility, sperm velocity, and total time of sperm activation were affected by dilution, storage temperature, and storage period (p &lt; 0.05). Procedures for semen storage should be performed with undiluted sperm cooled at 10°C, or kept undiluted at 25°C for up to 27 h.</p>


1973 ◽  
Vol 40 (2) ◽  
pp. 215-220 ◽  
Author(s):  
A. G. Perkin ◽  
M. J. Henschel ◽  
H. Burton

SummaryWhen heat treatments of the same sporicidal effectiveness were given, directly heated ultra-high-temperature sterilized milk gave twice as much sediment as indirectly heated milk after storage at room temperature for 100 days. Both types of process reduced the rate of clotting of the milk with pepsin and rennin, but the effect of the indirect process was markedly greater than that of the direct process.


2018 ◽  
Vol 38 (2) ◽  
pp. 151
Author(s):  
Irene Raras Nawangsasi ◽  
Yoyok Budi Pramono ◽  
Antonius Hintono ◽  
Vita Paramita

This experiment aims to the observed morphology, reduction of fineness and distribution particle deterioration of W/O/W double emulsion in instant noodle seasonings which is kept in 3 weeks with different storage temperature and NaCl level treatments. Emulsion structure has an important role to hamper salt release rate from internal to external phase. Structure breakdown shows system inability to maintain continuous salty taste perception during consumption because of the increasing salt release rate in storage period of instant noodle seasoning. Samples are treated with 3 variations of storage temperatures which are low (4 °C), room (25 °C), high temperature (40 °C) and 6 variations of NaCl level which are 0; 0,2; 0,4; 0,6; 0,8; 1%. Samples are categorized into 2 groups, double emulsions, and instant noodle seasonings. The double emulsion is made by 2 phases emulsification to get primary W/O emulsion and final W/O/W emulsion. This experiment showed that low and high-temperature storage affected emulsion and seasoning particle morphology, fineness and distribution throughout several instability phenomena.


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