• Food Science of Animal Resources
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• v.39 no.5
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• pp.725-741
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• 2019

In the current study, we first investigated a method for directly transforming lactose into galacto-oligosaccharides (GOS) for manufacturing low-lactose and GOS-enriched skim milk (GSM) and then evaluated its prebiotic potential by inoculating five strains of Bifidobacterium spp. In addition, fermented GSM (FGSM) was prepared using a potentially probiotic Lactobacillus strain and its fermentation characteristics and antioxidant capacities were determined. We found that GOS in GSM were metabolized by all five Bifidobacterium strains after incubation and promoted their growth. The levels of antioxidant activities including radical scavenging activities and 3-hydroxy-3-methylglutaryl-CoA reductase inhibition rate in GSM were significantly increased by fermentation with the probiotic Lactobacillus strain. Moreover, thirty-nine featured peptides in FGSM was detected. In particular, six peptides derived from ${\beta}$-casein, two peptides originated from ${\alpha}s_1$-casein and ${\kappa}$-casein were newly identified, respectively. Our findings indicate that GSM can potentially be used as a prebiotic substrate and FGSM can potentially prevent oxidative stress during the production of synbiotic fermented milk in the food industry.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.337-344
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• 1996

Gel-type yogurt was prepared from egg white powder (EWP), casein and glucose. The effects of EWP on acid production and growth of Lactobacillus were studied. The effect of EWP on sensory properties and volatile aroma compounds were also studied. Acid production by Lactobacillus in EWP (1-3%, W/V) was significantly lower than that by Lactobacillus in milk (control). However, the increase of EWP content from 1 to 3% increased acid production significantly, Number of viable cells of L. acidophilus at 24 hrs in milk and EWP containing samples (1-3%) was $3.1{\times}10^4/ml\;and\8.3{\times}10^7-3.6{\times}10^2/ml.$ respectively Sample containing lower amount of EWP generally showed lower number of viable cells. Sensory property of EWP samples (1-3%) was showed lower than that of milk yogurt (reference). However, sensory property of samples containing EWP 2% or 3% was significantly better than that of sample containing EWP 1%. Though the composition of volatile aroma compounds was slightly different from sample to sample, gas chromatographic analysis detected acetone, ethanol, diacetyl and acetoin in samples fermented by L. acidophilus.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.249-254
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• 2002

To determine the abilities as both lactic starter and probiotics for fermented foods, we investigated the potency of acid production, proteolytic activity and lactose metabolism of Lactobacillus amylovorus IMC-1. And the strain was cultured with lactococci in 10% skim milk medium. It was also examined the bactericidal action of antibacterial substance, produced by the strain IMC-1, against pathogenic bacteria. L. amylovorus IMC-1 showed excellent production of acid in 10% skim milk supplemented with yeast extract, and produced 0.8 and 2.7% of acid at 12 and 72 h incubation, respectively. It was found that the activity of ${\beta}-galactosidase$, about $39\;{\mu}M/minute/dry$ cell weight (mg), was stronger than that of $phospho-{\beta}-galactosidase$ in the strain IMC-1. The strain showed weak proteolytic activity in 10% skim milk, thus it produced 6 and $69\;{\mu}g/mL$ of free tyrosine at 12 and 72 h cultivation, respectively. It was known that the strain utilized mainly ${\alpha}-casein$ than ${\beta}-casein$ from patterns of SDS-PAGE. Mixed culture produced more acid than single cultures of L. amylovorus IMC-1 and Streptococcus thermophilus NIAI 510. Single culture of Str. thermophilus and mixed culture showed increasing cheese flavor with incubation times. Optimal fermentation time of mixed culture for the acid production and flora of lactic starter was 16 and 12 h by adding 0.1 and 0.5% of yeast extract to 10% skim milk, respectively. Antibacterial substance produced by the strain IMC-1 reduced about 2 log of the viable cell counts of both Escherichia coli O157 and Shigella flexneri after 24 and 4 h incubation, and they were not detected after 48 and 6 h incubation, respectively.

• Korean journal of food and cookery science
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• v.12 no.2
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• pp.153-161
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• 1996

A curd yogurt was prepared from egg white powder (EWP) and casein added with sugars (glucose, fructose, lactose). The effects of sugar addition on acid production and growth of Lactobacillus were studied. The effects of sugar addition on sensory property and volatile aroma compounds were also studied. Acid production by L. acidophilus in EWP 2％ (W/V), casein 3％ (w/v) and sugar 0.5,1 or 2％ W/V) was lower than that of L. acidophilus in milk (control). Acid production in sample added with glucose or fructose of 1％ or 2% (W/V) was higher than that of 0.5% (W/V), while acid production in lactose added sample was not affected with the concentration of lactose. Number of viable cells of L. acidophilus at 24 hr in milk, glucose added sample, fructose added sample and lactose added sample was 3.6${\times}$10/Sup 9/, 5.6${\times}$10$\^$8/, 6.0${\times}$10$\^$8/,and 3.2${\times}$10$\^$7/, respectively. Through 30hr fermentation, acid production and number of viable cells of L. acidophilus in milk were higher than those of sugar added samples. Sensory property of fructose added sample was slightly better than that of milk yogurt (reference), while that of lactose added sample was significantly inferior. Though the composition of volatile aroma compounds was slightly different according to sample, gas chromatographic analysis detected acetone, ethanol, diacetyl and acetoin in samples fermented by L. acidophilus.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.546-554
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• 1997

Gel-type yogurt was prepared from egg white powder (3%, w/v), glucose (2%, w/v) and four kinds of milk products (4%, w/v). The effects of milk product on acid production and growth of Lactobacillus were studied. The effects of milk product on sensory property and volatile aroma compounds were also studied. Acid production by L. acidophilus at 24 hr in samples containing milk product was significantly lower than that by L. acidophilus in milk (p<0.05). The sample containing casein produced less acid than the other samples. Number of viable cells of L. acidophilus at 24 hr in milk and samples containing milk product was $2.0{\times}10^{9}/mL$ and $5.0{\times}10^{8}{\sim}8.0{\times}10^{8}/mL$, respectively. Sensory property of the samples containing milk product was lower than that of milk yogurt (reference). However, sensory property of the sample containing casein was not significantly different from that of milk yogurt (p<0.05). The sample containing whey powder showed lower sensory score than other samples. Though the composition of volatile aroma compounds was slightly different from sample to sample, gas chromatographic analysis detected acetone, ethanol, diacetyl and acetoin in samples fermented by L. acidophilus.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.509-515
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• 1999

Lactic acid bacteria (LAB) fermented foods were prepared from egg white powder (EWP), casein and growth stimulating agents (GSA). The effects of GSA on acid production and growth of Lactobacillus were studied. The effects of GSA on sensory properties and viscosity of LAB fermented foods were also studied. Acid production by Lactobacillus was stimulated by addition of GSA (0.3% or 1%, W/V). Although stimulating effect differed among each GSA, some GSA increased the acidity up to the level of fermented milk. However, stimulating effect of GSA on viable cells was not noticeable. Acid production by L. acidophilus was generally higher than other Lactobacilli. The optimum concentration of GSA added to substrate was 1% (W/V). Sensory evaluation showed that the optimum fermentation time was 18hr. The sensory properties of GSA samples were evaluated as slightly lower than that of fermented milk because GSA samples showed whey separation and taste and smell of GSA. Apparent viscosity of GSA samples was significantly lower than that of fermented milk and control sample (p<0.05). There was no significant difference of apparent viscosity among GSA samples. GSA samples, fermented milk and control sample showed thixotropic flow characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1798-1807
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• 2002

This study was conducted to investigate lactobacillus salivarius subsp. salivarius having probiotic properties to be used as the health adjuncts with fermented milk products. Acid- and bile-tolerant lactobacillus salivarius subsp. salivarius was isolated with lactobacilli MRS broth from faeces of 80 healthy persons (infants, children and adults). It was used as a probiotic strain in fermented milk products. The pH of fermented milk decreased from pH 6.7 to 5.0 and titratable acidity increased from 0.3% to 1.0% by L. salivarius subsp. salivarius (isolation strain 20, 35, and 37), when incubated for 36 h at 37$^{\circ}C$. The number of viable cell counts of fermented milk was maximized at this incubation condition. The SDS-PAGE evidenced no significant change of casein but distinct changes of whey protein were observed by isolated L. salivarius subsp. salivarius for titratable acidity being incubated by 0.9-1.0% at 37$^{\circ}C$. All of the strains produced 83.43 to 131.96 mM of lactic acid and 5.39 to 26.85 mM of isobutyric acid in fermented products. The in vitro culture experiment was performed to evaluate ability to reduce cholesterol levels and antimicrobial activity in the growth medium. The selected L. salivarius subsp. salivarius reduced 23-38% of cholesterol content in lactobacilli MRS broth during bacterial growth for 24 h at 37$^{\circ}C$. All of the isolated L. salivarius subsp. salivarius had an excellent antibacterial activity with 15-25 mm of inhibition zone to E. coli KCTC1039, S. enteritidis KCCM3313, S. typhimurium M-15, and S. typhimurium KCCM40253 when its pH had not been adjusted. Also, all of the isolated L. salivarius subsp. salivarius had partial inhibition zone to E. coli KCTC1039, E. coli KCTC0115 and S. enteritidis KCCM3313 when it had been adjusted to pH 5.7. The selected strains were determined to have resistances of twelve antibiotic. Strains 27 and 35 among the L. salivarius subsp. salivarius showed the highest resistance to the antibiotics. These results indicated that some of the L. salivarius subsp. salivarius (strain 27 and 35) are considered as effective probiotic strains with a potential for industrial applications, but the further study is needed to establish their use as probiotics in vivo.

• Journal of Dairy Science and Biotechnology
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• v.24 no.1
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• pp.65-73
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• 2006

This study was to review recent reports in effects of various starter cultures on the viscosity in stirred yogurt. The rheological properties of yogurt have received considerable attention in the literature. Most yogurts are typically made by mixed cultures of Lactobacillus bulgaricus and Streptococcus thermophilus. The viscosity of yogurt made by mixed cultures was much higher than that of yogurt by single cultures. Since texture of stirred yogurt is the result of both acid aggregation of casein micelles and production of exopoly-saccharides, it is suggested that yogurt be made by the exopolysaccharide-producing cultures in order to increase viscosity, Both types of exopolysaccharides are capsule and loose slime(ropy). But it is desirable to use encapsulated nonropy strains. And Bifidobacteria affects adversely to the viscosity of yogurt. Therefore, starter cultures which have an effect on yogurt viscosity have been widely demonstrated. This review is the search for the development of viscosity in stirred yogurt.

• Food Science and Preservation
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• v.31 no.1
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• pp.138-148
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• 2024

The production of poly-γ-glutamic acid (γ-PGA) and γ-aminobutyric acid (GABA) was optimized by serial fermentation of Dendropanax morbiferus extract (DME) using Bacillus subtilis HA and Lactobacillus plantarum KS2020. The 1st alkaline fermentation was performed on 60% DME including 2% glucose and 10% monosodium ʟ-glutamate (MSG) as a precursor. The 1^st fermented DME had 57 mg% tyrosine. Consequently, the 2^nd lactic acid fermentation for 5 days increased the tyrosine content of 106 mg%. The mucilage containing γ-PGA showed a high content of 3.50% on the first day of alkaline fermentation and then increased to 4.10% after 2 days. The precursor (MSG) remaining in the 1^st fermented DME was efficiently converted to GABA by the 2^nd lactic acid fermentation in the presence of 5% skim milk, 1.5% glucose and 0.5% yeast extract, resulting in the production of 18.29 mg/mL GABA. The viable cells of lactic acid bacteria increased and indicated 9.49 log CFU/mL on the fermentation for 5 days, and the acidity of co-fermented DME indicated the highest value of 1.55%. Conclusively, the serial fermented DME has multi-functional ingredients containing γ-PGA, GABA, peptides and probiotics.

• Journal of Dairy Science and Biotechnology
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• v.32 no.2
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• pp.131-139
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• 2014

The aim of this study was to manufacture Cutting-Gouda cheese and to investigate the change in physicochemical properties of Cutting-Gouda cheese made with Lactobacillus rhamnosus_p1. Lactic acid bacteria were isolated from Gouda cheese ripened for more than 1 year. They were identified as 2 strains of L. rhamnosus, Lactobacillus casei, Lactobacillus curvatus, and Staphylococcus saprophyticus by 16S rDNA sequencing and named L. rhamnosus_p1, L. casei_p2, L. curvatus_p3, L. rhamnosus_p4 and S. saprophyticus_p5. The proteolytic activities of isolated strains against casein were measured using prepared skim milk agar plates. L. rhamnosus_p1 showed the highest proteolytic activity. Cutting-Gouda cheese was made with L. rhamnosus_p1, and its physicochemical properties (moisture, protein, fat, ash and free amino acid content) were measured during ripening periods. Because of the modified atmosphere packaging ($N_2{^-}$), there was no change in moisture, protein, fat, and ash in the experimental group. The total amount of free amino acids in the control and experimental group gradually increased during ripening periods. The sensory evaluation showed that the experimental group was preferable to the control group. This result suggests that L. rhamnosus_p1 has potential to be developed as a new starter for Gouda cheese.