• Journal of Dairy Science and Biotechnology
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• v.41 no.3
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• pp.149-156
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• 2023

Milk protein is often fractionated/concentrated by using various techniques in dairy industries. Among these techniques, ultrafiltration (UF) is particularly efficient at concentrating the casein fraction of milk protein. The objectives of this study were to produce casein hydrolysates by concentrating the casein fraction in skim milk using the UF technique and to investigate the chemical composition of the casein hydrolysates. The skim milk was concentrated using a UF laboratory test unit equipped with 10 kDa and 30 kDa membranes. After UF, the protein content of the milk was concentrated up to ~7.2% and the Ca was concentrated up to ~196 mg/100 g of milk. Trypsin was then added to the concentrated skim milk to produce the casein hydrolysates. The results of sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed that the casein fraction was not present after hydrolysis, indicating that casein in the milk had been hydrolyzed. The Ca content in the casein hydrolysates was much higher (p<0.05) compared to Ca content in commercial casein phosphopeptides (CPP) indicating that was acidified during the manufacture of commercial CPP. In conclusion, it seems that casein hydrolysates containing large concentrations of protein and Ca can also be made from concentrated UF milk without acidification or renneting.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.18-22
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• 2007

The objective of this study was to develop and assess the performance of an aseptic system for liquid milk contained in plastic bottles, from a small-scale production standpoint. Commercial sterility tests conducted on the bottled milk were utilized in our assessments of the system, via the identification and monitoring of the principal points of the process. Four 150 L batches of milk with pH values of approximately 6.7 were heat-processed at between 137 and $143^{\circ}C$ for 10 see in a plate heat exchanger, and then aseptically transferred to 500 mL high-density polyethylene (HOPE) bottles, in an ISO class 7 clean room. The aseptic condition of the bottles was achieved via 10 see of rinsing with a mixture containing 0.5% peracetic acid and 0.8% hydrogen peroxide at $30^{\circ}C$, followed by another rinse with sterile water. Of the 4 batches processed, 2 were determined to exhibit commercial sterility, on the basis of the physical-chemical and microbiological criteria adopted. It was concluded that some adjustment of the processing line was required in order to achieve full commercial sterility for all processes. The aseptic system developed and assessed in this study was demonstrated to have great potential for the processing and transferring of milk into plastic bottles, from a small-scale production standpoint.

• Korean Journal of Food Science and Technology
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• v.12 no.3
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• pp.165-169
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• 1980

Consumer acceptance and preference tests for commercial milk were run with laboratory consumer panel. The results were summarized as follows: 1. According to result of the paired comparison preference test between milk K and each of 4 commercial milk tested a significant difference in the consumer preference was not recognized at 5 percent level 2. According to result of hedonic scale test for commercial milk, a significant difference on both treatment and panel member effect was not recognized at 5 percent level. 3. According to result of food action scale test for commercial milk, the frequency of 'I would drink this every opportunity I had' was the highest as 38 percent. 4. According to the rank test for the determination of the preference for milk flavor on the temperature of sample, the frequency of sampling at $20^{\circ}C$ was the highest. 5. A significant difference on the flavor of milk was recognized among 5 samples of commercial milk by both difference test and profile test as reported in the previous paper (Korean J. Food Sci. Technol. 12(3), 150 and 158(1980)), but not by rank test, preference test and hedonic scale test. This fact suggests that rank test, preference test and hedonic scale test are influenced by the difference on the preference of the panel members and on the basis of quality, etc.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.369-376
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• 2013

Milk is well known to be rich in some nutrients such as protein, calcium, phosphorus, and vitamins. In particular, absorption and bioavailability of calcium receive lots of attention because calcium is very little absorbed until it is changed to the ionized form in the intestine. In this study, concentration of the soluble calcium was determined in the commercial bovine milk products, which were processed by different heat-treatment methods for pasteurization. As for general constituents, lactose, fat, protein, and mineral were almost same in the liquid milk products by different processors. Ultrafiltration of the skimmed milk caused little change in the permeate as for lactose content but both fat and protein decreased. pH values ranges from 6.57-6.62 at room temperature and slightly increase after centrifugation, 10,000 g, 10 min. Rennet-coagulation activity was the lowest in the ultra high temperature (UHT-)milk compared to the low temperature long time (LTLT-) and high temperature short time (HTST-)milk products. Each bovine milk products contains 1056.5-1111.3 mg/kg of Ca. The content of sulfhydryl group was the lowest in raw milk compared to the commercial products tested. For the skimmed milks after ultrafiltration with a membrane (Mw cut-off, 3 Kd), soluble Ca in the raw milk was highest at 450.2 mg/kg, followed by LTLT-milk 336.4-345.1 mg/kg, HTST-milk 305.5-313.3 mg/kg, UHT-milk 370.3-380.2 mg/kg in the decreasing order. After secondary ultrafiltration with a membrane (Mw cut-off, 1 kD), total calcium in raw milk had a highest of 444.2 mg/kg, and those in the market milk products. As follow: UHT-milk, 371.3 to 378.2 mg/kg; LTLT-milk, 333.3 to 342.2 mg/kg; HTST-milk 301.9 to 311.2 mg/kg in a decreasing order.

• Journal of Food Hygiene and Safety
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• v.26 no.4
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• pp.349-354
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• 2011

Our objective in this study is to assess the safety of docosahexaenoic acid (DHA) fortified milk of dairy cows fed feeds containing protected fish oil treated with formaldehyde by analyzing formaldehyde concentration in commercial milk and DHA fortified milk of dairy cows fed formaldehyde treated feed. There are 3 milk samples in this study: Commercial milk (CM), DHA fortified milk for Kid (DHA-K) and DHA fortified milk for Baby (DHA-B). We confirm the fresh quality of these three samples by physicochemical tests. In fat content result, three groups are significantly different at the p < 0.05 by Duncan's multiple range test, but fat content of group DHA-K is about half the level of the other two groups. Protein content of group DHA-K is 1 % higher than other two groups. According to the analysis result of DHA content of DHA fortified milk, DHA content of DHA-B is two-fold higher than DHA-K. Similar pattern was seen in the intake based on age. According to HPLC analysis result of formaldehyde concentration in milk, commercial milk and DHA fortified milk are between 0.013 ppm and 0.057 ppm which is formaldehyde standard level in fresh milk settled in WHO (World Health Organization). Three groups have no significantly differences at the p < 0.05 by Duncan's multiple range test. For this reason, it can be concluded that there is no transition of formaldehyde from dairy cows fed formaldehyde treated feeds to its produced milk. Safety about formaldehyde of DHA fortified milk of dairy cows fed formaldehyde treated feeds is considered similar to commercial milk.

• Journal of Dairy Science and Biotechnology
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• v.26 no.1
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• pp.27-36
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• 2008

This review was written to introduce updated data on the structure and function of the major milk proteins identified as allergens, the characterization of their epitopes in each allergenic milk proteins, and the reduction of milk protein allergenicity. Most mammalian milk protein, even protein present at low concentration, are potential allergens. Epitopes identified in milk proteins are both conformational(structured epitope) and sequential epitopes(linear epitope), throughout the protein molecules. Epitopes on casein and whey proteins are reported to be sequential epitope and conformational epitopes, respectively. Conformational epitopes on whey protein are changed into sequential epitope by heat denaturation during heat treatment. Several methods have been proposed to reduce allergenicity of milk proteins. Most ideal and acceptable method to make hypoallergenic milk or formula, so far, is the hydrolysis of allergenic milk proteins by enzymes that has substrate specificity, such as pepsin, trypsin, or chymotrypsin. Commercial formulas based on milk protein hydrolysate are available for therapeutic purpose, hypoantigenic formula for infants from families with a history of milk allergy and hypoallergenic formula for infants with existing allergic symptoms.

• Archives of Pharmacal Research
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• v.17 no.5
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• pp.318-322
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• 1994

Upon gel filtration, the commercial bovine milk xanthine oxidase preparation was fractionated into two preparations showing enzyme activity. Native polyacrylamide gel electrophoresis showed that one was in a dimeric form and the other was a monomer having molecular weight of 150 kDa. It was also found that this commercial enzyme existed mostly in an active monomeric form without loss of enzyme activity. The rabbit antisera produced against two enzyme preparations cross-reacted well each other. In SDS-polyacrylamide gtel electro-phoresis, however, both enzyme preparations yielded two smaller protein bands below 150 kDa, which appeared to bind with both antisera with high affinity but not to retain enzyme activity. It implies that bovine milk xanthine oxidase can lose its activity when monomeric subunit is further degraded.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.3
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• pp.345-349
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• 2005

A study was conducted to determine the effect of feeding chopped whole sugar cane compared to corn silage on performances of dairy cows during the dry season. Twenty four Holstein Friesian crossbred (>87.5% Holstein Friesian) lactating dairy cows in mid lactation; averaging 16.5${\pm}$2.0 kg of milk, 121${\pm}$22 days in milk, 54.5${\pm}$4.5 months old and 440${\pm}$31 kg live weight, were stratified for milk yield, days in milk, age, stage of lactation and body weight, and then randomly allocated to two treatment groups (12 cows in each group). The first group was fed corn silage together with commercial concentrate while the second group was fed chopped whole sugar cane together with commercial concentrate. All cows consumed similar DM, however, cows on corn silage consumed more CP while cows on chopped whole sugar cane consumed more $NE_{LP}$. No significant differences in performances between the two groups were observed except for final live weight and body weight change. Cows on chopped whole sugar cane showed higher final live weight and gained more weight than cows on corn silage. The present study clearly indicates that chopped whole sugar cane can be fed to lactating dairy cows, while giving similar milk yield to corn silage.

• Journal of Microbiology and Biotechnology
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• v.29 no.11
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• pp.1717-1728
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• 2019

The gene encoding β-galactosidase was cloned from Bifidobacterium longum RD47 with combinations of several bifidobacterial promoters, and expressed in B. bifidum BGN4. Among the recombinant bifidobacteria, BGN4+G1 showed the highest β-galactosidase level, for which the hydrolytic activity was continuously 2.5 to 4.2 times higher than that of BGN4 and 4.3 to 9.6 times higher than that of RD47. The β-galactosidase activity of BGN4+G1 was exceedingly superior to that of any of the other 35 lactic acid bacteria. When commercial whole milk and BGN4+G1 were reacted, BGN4+G1 removed nearly 50% of the lactose in the milk by the 63-h time point, and a final 61% at 93 h. These figures are about twice the lactose removal rate of conventional fermented milk. As for the reaction of commercial whole milk and crude enzyme extract from BGN4+G1, the β-galactosidase of BGN4+G1 eliminated 51% of the lactose in milk in 2 h. As shown below, we also compared the strengths and characteristics of the strong bifidobacterial promoters reported by previous studies.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.2
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• pp.205-208
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• 2002

The use of chopped sugarcane stalk (CSS) as a roughage for lactating cows was examined using four Holstein crossbred cows in a private dairy farm in Khon Kaen, Thailand, in comparison with rice straw (RS), which is the conventional roughage in the dry season in the region. Cows were subjected to the following two dietary treatments: Diet 1) RS with commercial concentrate feed, and Diet 2) CSS and RS with commercial concentrate feed. The diet was switched over every 3 weeks. The amount of concentrate was determined by the experience of the owner of the cows. RS and CSS were given ad libitum. There was no difference in milk production between two groups, although the total DMI was less in cows fed CSS. Solid-not-fat (SNF) content in milk was significantly higher in the cows given CSS. The NEFA content was significantly lower in the animals given CSS, which suggested that cows given only RS as roughage would be suffering from energy malnutrition. Therefore, it was considered that CSS feeding improved energy supply, which resulted in higher SNF in milk. In the nutritional point of view, the present study clearly showed CSS can be used as a roughage for dairy cows in the dry season.