• Korean Journal of Food Science and Technology
• /
• v.29 no.3
• /
• pp.539-545
• /
• 1997

Lactobacillus bulgaricus and Kluyveromyces lactis were inoculated to Jangyeob and Jinpum soy milks together after the addition of different amounts of lactose to increase the contents of oligosaccharides, which were compared with single cultured samples. The contents of stachyose, raffinose, sucrose, and glucose of samples without lactose decreased by single culture method, but the oligosaccharides decreased less than in single cultured samples containing of lactose. The oligosaccharides of single cultured samples were equal or decreased compared with soy milks. While those of mixed cultured Jangyeob and Jinpum samples containing 2% lactose for 24 hr incubation increased 125.0% and 118.1%, respectively and those of samples for 36 hr incubation increased 127.0% and 141.0%, respectively, those of mixed cultured samples containing 4% lactose for 24 hr incubation increased 112.5% and 123.0%, respectively and those of samples for 36 hr incubation increased 120% and 135.9%, respectively. Therefore, the oligosaccharides in samples containing 2% lactose were slightly more than in samples containing 4% lactose. Among the cultured methods, oligosaccharides were produced in the largest amounts by the mixed culture for 36 hr. The addition of lactose in soy milks for soy yogurts was effective in the formation of oligosaccharides since the galactose, produced by the hydrolysis of lactose, was thought to be combined with sucrose by the action of ${\beta}-galactosidase$ in yeast.

• Korean Journal of Food Science and Technology
• /
• v.29 no.3
• /
• pp.533-538
• /
• 1997

Lactobacillus bulgaricus and Kluyveromyces lactic were inoculated to Jangyeob and Jinpum soymilks single or together after the addition of different amounts of lactose to increase the formation of lactic acid and sensory evaluation. The decrease of pH and the increase of acid production during the fermentation of soy yogurts were more effective when lactose was added. And the single culture method was more effective in decreasing pH and in increasing acid production than the mixed culture method. Without lactose, the growth of lactic acid bacteria in samples increased by mixed culture method than by single culture method. However, the growth of lactic acid bacteria increased more in the by single cultured samples than in the mixed cultured samples by the addition of lactose. Beany flavor decreased more in soy yogurts compared with Jangyeob and Jinpum soy milks, and Jinpum soy yogurts had less beany flavor than Jangyeob soy yogurts. In sour taste, Jangyeob soy yogurt prepared by mixed culture for 36 hr incubation with 4% lactose showed the poorest score, while soy yogurts containing 2% lactose showed significantly better scores and no significant difference compared with milk yogurt. Soy yogurts containing 2% lactose showed no significant difference in overall acceptability compared with milk yogurt.

• Journal of Dairy Science and Biotechnology
• /
• v.38 no.1
• /
• pp.1-18
• /
• 2020

Lactose intolerance is a pathophysiological phenomenon caused by a deficiency of the enzyme lactase present in human intestines. Changes in intestinal digestion and colon fermentation after the intake of lactose-containing products cause diarrhea and other clinical discomforts. Therefore, lactose intolerance can be easily ameliorated by consuming lactose hydrolyzed milk and dairy products. In the recent years, lactose-free dairy products have provided lactose intolerant consumers with several options, due to an improvement in the quality and an increase in the variety of products. Currently, the manufacturing of lactose-free products also represents the fastest growing sector in the dairy industry. This review, thus, aims to provide an overview of the current availability and prospects of lactose-free dairy products, and also discuss the potential benefits of the development of a variety of lactose-free dairy foods.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.6
• /
• pp.989-993
• /
• 2007

A lactose-hydrolyzed milk with low sweetness was developed using nanofiltration. Raw milk was treated with 0.03% ${\beta}$-galactosidase at $4^{\circ}C$ for 24 h to hydrolyze lactose partially. The resultant lactose-hydrolyzed milk containing 0.43% lactose was then concentrated using a nanofiltration membrane to reach concentration factor of 2.13. The concentration factors and coefficients of retention of milk components in nanofiltration were determined. The concentration factor of milk fat was 2.20 which was the highest of the milk components. The coefficient of retention of calcium and riboflavin was 0.96 and 0.76, respectively. However, the coefficient of retention of glucose, galactose, and sodium was 0.21, 0.15, and 0.22, respectively. Raw milk was treated with 0.1% ${\beta}$-galactosidase at $4^{\circ}C$ for 40 h to hydrolyze lactose fully and then concentrated to reach a concentration factor of 1.6 by using nanofiltration. The concentrated milk was reconstituted with water. The lactose-hydrolyzed milk had sweetness similar to milk. The compositional ratios of crude protein, calcium, sodium, and riboflavin of lactose-hydrolyzed nanofiltrated milk to those of raw milk were 99%, 97%, 77%, and 80%, respectively. This study showed that nanofiltration of lactose-hydrolyzed milk to remove galactose and glucose did not cause significant loss of calcium. The lactose-hydrolyzed nanofiltrated milk contained 0.06% lactose and had sweetness similar to milk.

• Journal of Dairy Science and Biotechnology
• /
• v.39 no.1
• /
• pp.20-26
• /
• 2021

Lactase (β-galactosidase) is abundant in the small intestine during early childhood and gradually decreases with age. Lactic acid bacteria (LAB) present in yogurt could survive in the stomach, and lactase produced by these LAB can aid in lactose breakdown in the small intestine, thereby reducing lactose intolerance. This study aims to provide preliminary data for development of lactose-free yogurts for the elderly, and investigate the effect of lactose-hydrolyzed milk on the growth of starter cultures. The pH during yogurt fermentation using lactose-free milk was slightly higher at 2 and 4 h of incubation, but reached 4.5 at the end of incubation, similar to that of the yogurt prepared from regular milk. The number of viable cells of Streptococcus thermophilus reached 108 CFU/mL after 2 h of incubation and increased to 109 CFU/mL after 4 h of incubation. During yogurt fermentation, the viable cells of Lactobacillus species and Bifidobacterium longum did not affect lactose hydrolysis. Although lactose-hydrolyzed milk did not promote the growth of starter cultures, manufacturing yogurt with lactose-free milk could be beneficial for the intestinal health of lactose-sensitive elderly.

• Journal of Nutrition and Health
• /
• v.15 no.1
• /
• pp.1-8
• /
• 1982

The effects of lactose on the formation of casein phosphopeptide (CPP), the increment of soluble calcium and the enhancement of calcium absorption by dietary casein in the intestinal tract were investigated. Rats were fed a lactose-free diet, 10% lactose diet and 30% lactose diet containing powdered milk. In rats receiving a lactose-free powdered milk diet, CPP formation was confirmed by gel filtration of the intestinal content on Sephadex G -25 and the amount of soluble calcium was increased in the small intestine and calcium absorption, measured by the ligated ideal loops in situ was enhanced. However, In rats receiving a powdered milk diet containing 10% lactose or 30% lactose, the similar effects were not seen. These observations indicate that CPP-stimulated effects on soluble calcium and calcium absorption in the small intestine are not dependent upon lactose.

• Journal of Microbiology and Biotechnology
• /
• v.4 no.2
• /
• pp.155-159
• /
• 1994

Two Zymomonas mobilis strains (ZM63 and ZM6307), containing both lactose and galactose operons, were constructed. $\beta$-Galactosidase and galactokinase assays indicated that both operons were expressed in both strains. The transport systems available for lactose uptake by Zymomonas mobilis were investigated using $^{14}C$-labelled lactose. After the outer membrane, which was considered to be a possible barrier to lactose uptake, was disrupted by treatment with EDTA and $Ca^{2+}$ ions, some increase in lactose uptake was observed in ZM6306 ($lac^+$) and ZM6307 ($lac^+\;gal^+$), but not in the parent, ZM6. This suggested that the outer membrane of Zymomonas mobilis acts as a barrier to lactose uptake to some degree, and also that the lactose permease is operational in Zymomonas mobilis.

• Korean Journal of Animal Reproduction
• /
• v.20 no.2
• /
• pp.101-109
• /
• 1996

This study was done to find out the methods of long-term use of liquid boar semen in 100 ml plastic bottle for artificial insemination and to investigate differences between Lactose-Egg yolk and Biitschwiler diluents according to storage temperature, and effect of final glycerol concent ration in Lactose-Egg yolk diluent. Liquid boar semen diluted with Lactose-Egg yolk diluent showed significantly higher sperm motility (p<0.05) after 0.5 and 2h incubation at 37$^{\circ}C$,than Butschwiler diluent at all storage length when it was preserved in the 5$^{\circ}C$ refrigerator. The NAR acrosome in Lactose-Egg yolk diluent a after 0.5 and 2h incubation at 37$^{\circ}C$, respectively, during preservation periods was similar to that in Biitschwiler diluent. When liquid boar semen was preserved at 15$^{\circ}C$, liquid boar semen in the Butschwiler diluent showed significantly higher percentages of sperm motility and NAR acrosome from third day to seventh than that in Lactose-Egg yolk diluent. In the effect of final glycerol concentration of liquid boar semen in the Lactose-Egg yolk diluent, the final glycerol concentration of 2% showed higer percentages of sperm motility and NAR acrosome than that of 0, 1, 3, and 5%. Farrowing rate, litter size and average pig weight at birth did not differ significantly between Lactose-Egg yolk and But schwiler diluents. As a result of this study, we found out that liquid boar semen can be stored for 6-7 days at 5$^{\circ}C$ in Lactose-Egg yolk diluent and at 15$^{\circ}C$ in Butschwiler diluent.

• KSBB Journal
• /
• v.20 no.1 s.90
• /
• pp.26-33
• /
• 2005

The effects of carbon sources for exopolysaccharide production during batch cultivation of an Enterobacter sp. isolated from the composter were investigated. The highest amount of exopolysaccharide was obtained when lactose was used as carbon source. Lactose in medium was converted into glucose and galactose. Glucose was metabolized fast and was completely consumed, but about $20\%$ of lactose was accumulated as galactose. On the other hand, enzyme activity was about $350\~450$ unit with the increase of lactose concentration. Thus, it was considered that the exopolysaccharide might be produced in the course of that lactose was hydrolyzed into glucose and galactose by $\beta-galactosidase$ with respect to that enzyme activity on lactose hydrolysis was accorded to the exopolysaccharide production. When glucose and galactose were added to lactose medium, respectively, it could be considered that glucose was as a repressor and galactose was as a inducer for $\beta-galactosidase$ synthesis even though the mechanisms were not elucidated. The increase of lactose concentration was almost ineffective to the specific growth rate $(0.133\~0.151\;hr^[-1})$ but showed the difference in the biomass content. The higher carbon source concentration, the more residual sugar remained. It was assumed that the optimum lactose concentration for exopolysaccharide production was $30\~70g/L.$ On the other hand, it was considered that the nitrogen acted as growth limiting nutrients to the cell growth. In the cases of 30 and 70 g/L of the fixed carbon concentrations, the increase of the nitrogen sources concentration caused a remarkable increase within the range of $0.059\~0.225\;hr^{-1}$ and $0.141\~0.237hr^{-1}$ of the specific growth rate, respectively, while there was no significant difference in biomass.

• Korean Journal of Microbiology
• /
• v.27 no.3
• /
• pp.181-187
• /
• 1989

Plasmid DNA was isolated from Lactobacillus casei SW-M1($Lac^{+}$strain). The curing frequencies of pPLac plasmid from L. casei SW-M1 showed 43% for acriflavin treatment and 53% for ethidium bromide treatment after 3 times transfer. On the charaterization of pPLac plasmid, it was found that the plasmid contained gene encoding phospho-$\beta$-galactosidase for lactose utilization. Lactose-PTS(phosphotransferase system)was involved in membrane transport system in $Lac^{+}$ strain. Induction of phospho-$\beta$-galactosidase was specially effective by galactose, lower effect with lactose and glucose but not by IPTG(isopropyl-$\beta$-D-thiogalactoside). This result showed that induction of phospho-$\beta$-galactosidase by IPTG did not appeared. The catabolite repression of phospho-$\beta$-galactosidase synthesis by glucose was not found in L. casei.