• Korean Journal of Food Science and Technology
• /
• v.31 no.1
• /
• pp.24-29
• /
• 1999

The physicochemical properties of tagatose, a low calorie sweetener, was investigated. Rheological property of tagatose solution was found to be Bingham fluid. As the concentration of tagatose increased from 10 to 50% at $25^{\circ}C$, the viscosity increased from 1.65 to 5.14 cp. When the temperature of 40% tagatose solution increased from 15 to $55^{\circ}C$, the viscosity decreased from 4.59 to 2.33cp. The melting onset temperature and endothermic enthalpy of tagatose were $130.4^{\circ}C$ and -202.3 J/g, respectively, which were obtained from the analysis of differential scanning calorimetry. Tagatose showed higher water absorption than sucrose under $85{\sim}100%$ of relative humidity. Tagatose was less soluble than sucrose at $20{\sim}70^{\circ}C$. Water activity of tagatose in 60% concentration was 0.892, which was lower than 0.957 of sucrose solution. Tagatose solution adjusted from pH 2 to pH 12 was stable after 3 days. Amount of tagatose was not changed after heat treatment at $154^{\circ}C$ for 4 hours. But a browning reaction was found and absorbance of a tagatose solution increased with heat treatment.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2000.04a
• /
• pp.68-75
• /
• 2000

D-Tagatose is a potential bulking agent in food as a non-calorific sweetener. To produce D-tagatose from cheaper resources, plasmids harboring the L-arabinose isomerase gene (araA) from Escherichia coli was constructed because L-arabinose isomerase was previously suggested as an enzyme that mediates the bioconversion of galactose to tagatose as well as that of arabinose to ribulose. In the cultures of recombinant E.coli with pTC101, which harboring araA of E.coli, tagatose was produced from galactose in 9.9 % yield. The enzyme extract of E.coli containing pTC101 also converted galactose into tagatose in 96.4 % yield. For the economic production of D-tagatose, an L-arabinose isomerase of E.coli was immobilized using covalent binding on agarose. While the free L-arabinose isomerase produced tagatose with the rate of 0.48 mg/U$.$day, the immobilized one stably converted galactose into average 7.5 g/l$.$day of tagatose during 7 days with higher productivity of 0.87 mg/U$.$day. In the scaled up immobilized enzyme system, 99.9 g/l of tagatose was produced from galactose with 20 % equilibrium in 48 hrs. The process was stably repeated additional 2 times with tagatose production of 104.1 and 103.5 g/l.

• Korean Journal of Food Science and Technology
• /
• v.30 no.1
• /
• pp.237-240
• /
• 1998

The application of a low calorie sweetener, tagatose, to chocolate product was investigated. The viscosity of chocolate prepared with tagatose were almost the same as that of chocolate with sucrose. The melting point and endothermic enthalpy of chocolate prepared with tagatose, which were obtained from the analysis of differential scanning calorimetry, were also almost the same as those of chocolate with sucrose. However, chocolate with tagatose was softer than that of chocolate with sucrose.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.3
• /
• pp.348-354
• /
• 2013

To investigate the effect of tagatose on the growth of intestinal bacteria, various species were cultivated individually on m-PYF medium containing tagatose as a carbon source. The tagatose inhibited the growth of intestinal harmful microorganisms such as Staphylococcus aureus subsp. aureus, Listeria monocytogenes, Vibrio parahaemolyticus, Salmonella Typhimurium, and Pseudomonas fluorescens. In the case of beneficial microorganisms found in the intestine, Lactobacillus casei grew effectively on m-PYF medium containing tagatose, while Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc citreum, and Lactobacillus acidophilus did not. To examine the effect of tagatose on fermentation by Lactobacillus casei, yogurt was prepared with tagatose as a carbon source. The resulting acid production stimulated a remarkable growth of lactic acid bacteria in the yogurt. After fermentation for 24 hours, the viable cell count and viscosity of yogurt were above 8.49 log CFU/mL and 1,266 cps, respectively. Moreover, sensory evaluations showed that the yogurt supplemented with tagatose was as acceptable as control yogurt prepared with glucose as a carbon source. The changes in pH, titratable acidity and lactic acid bacteria in yogurt prepared with tagatose did not show any significant changes during storage for 15 days at $4^{\circ}C$.

• Microbiology and Biotechnology Letters
• /
• v.26 no.3
• /
• pp.250-256
• /
• 1998

D-Tagatose production from D-galactose was investigated using 35 type strains of American Culture Type Collection (ATCC) and Korean Collection for Type Cultures (KCTC) which have potential to produce D-tagatose. Enterobacter agglomerans ATCC 27987 was selected as a D-tagatose producing strain due to its short fermentation time and high production of D-tagatose. Optimization of the culture conditions for D-tagatose production by E. agglomerans ATCC 27987 was performed. Among various carbon sources, D-galactose was the most effective carbon source for D-tagatose production. As the D-galactose concentration was increased, cell growth and D-tagatose production increased. Effect of nitrogen sources on D-tagatose production was studied. Of inorganic nitrogen sources, ammonium sulfate was effective one for D-tagatose production and yeast extract was the most suitable organic nitrogen nutrient. The concentrations of inorganic compounds such as KH$_2$PO$_4$, K$_2$HPO$_4$, and MgSO$_4$$.$7H$_2$O were also optimized for D-tagatose production. The optimal medium was determined to contain D-galactose of 20 g/l, yeast extract of 5.0 g/l, (NH$_4$)$_2$SO$_4$ of 2.0 g/l, KH$_2$PO$_4$ of 5.0 g/l, K$_2$HPO of 5.0 g/l, and MgSO$_4$$.$7H$_2$O of 5 mg/l. The optimal environmental conditions in a 250-$m\ell$ flask were found to be pH of 6.0, temperature of 30$^{\circ}C$, and agitation speed of 150 rpm. D-tagatose of 0.41 g/l could be obtained in 24 h from 20 g/l D-galactose at the optimal culture condition without induction and cell concentration.

• Korean Journal of Food Science and Technology
• /
• v.35 no.5
• /
• pp.898-904
• /
• 2003

This study was conducted to observe the effect of various kinds of sugars and their molar concentrations on the Maillard browning reaction. To observe the effects of various kinds of sugar, glucose, fructose, tagatose, xylose, and sucrose were employed. A model solution consisting of 0.2 M sugar and 0.2 M glycine was prepared and heated at $100^{\circ}C$ for 5 hr. The model solution with adjusted concentrations of either tagatose or glycine was also heated at $100^{\circ}C$ for 5 hr. Tagatose showed the fastest Maillard reaction, followed by xylose, fructose, glucose, and sucrose. After glycine concentration of the model solution was fixed, the model solution showed more browning with an increase in tagatose concentration. When the tagatose concentration of the model solution was fixed, the model solution showed more browning with an increase in glycine concentration. The model solution with a fixed concentration of glycine showed more more browning than that with a fixed concentration of tagatose, since the former had higher amounts of the reactant.

• Food Science and Biotechnology
• /
• v.17 no.3
• /
• pp.655-658
• /
• 2008

Although arabinose isomerase (E.C. 5.3.1.4), a commercial enzyme for edible tagatose bioconversion, can be expressed in an Escherichia coli system, this expression system might leave noxious by-products in food. To develop an eligible tagatose bioconversion with food-safe system, we compared the tagatose production activity of immobilized arabinose isomerase expressed in Bacillus subtilis (a host generally recognized as safe) with that of the enzyme expressed in E. coli. A 48% increase in tagatose production (4.3 g tagatose/L at $69.4\;mg/L{\cdot}hr$) was found using the B. subtilis-expressed immobilized enzyme system, compared to the E. coli-expressed enzyme system (2.9 g tagatose/L). The increased productivity with safety of the B. subtilis-expressed arabinose isomerase suggests that it is a more eligible candidate for commercial tagatose production.

• Journal of the East Asian Society of Dietary Life
• /
• v.24 no.6
• /
• pp.802-810
• /
• 2014

This study investigated the quality characteristics of muffins prepared with tagatose. The effect of tagatose were evaluated in terms of height, volume, weight, specific volume, baking loss rate, moisture contents, colorimeter, sensory evaluation, and texture of muffins during storage (1, 3, 5 days) and texture was measured using a texture analyzer. As the ratio of tagatose increased, the volume, specific volume, baking loss rate, and height decreased, whereas moisture content increased. During storage, control without tagatose showed the highest springiness lowest hardness by TPA, whereas hardness of muffins increased and springiness decreased as the contents of tagatose increased. Lightness of crust and crumb decreased significantly as contents of tagatose increased. According to the sensory evaluation, the control group showed the highest score in terms of texture but was not significant with 2% tagatose (T2). For appearance, color, flavor, taste, and overall acceptance, T2 showed the best result.

• Food Industry And Nutrition
• /
• v.2 no.1
• /
• pp.16-21
• /
• 1997

Microbial of enzymatical methods are suitable for production of rare monosaccharides. Using oxidation and reduction ability of Microorganisms, various rare ketoses and polyols can be produced, for example D-tagatose from galagtitol by Enterobacter agglomerans strain 221e. L-tagatose from galactitol by Klebsiella pheumonias strain 40b, L-psicose from allitol by Gluconobacter frateurii IFO 3254, D-talitol from d-tagatose by Aureobasidium pullulans strain 113B, allitol from D-psicose by Enterobacter agglomerans strain 221e and so on. We can produce various rare aldoses and ketoses using aldose isomerases, for example L-galactose from L-tagatose by D-arabnose isomerase, and L-ribose from L-ribulose by L-isomerase, and so on. D-Tagatose 3-epimerase of Pseudomonas sp. ST-24 is very useful for preparationof various rare ketoses, for example D-psicose from D-fructose, D-sorbose from D-tagatose, L-fructose, from L-psicose and so on. Using polyol dehydrogenases, aldose isomerases and D-tagatose 3-epimerase, we can design the suitable for production of a certain rare monosaccharide from a suitable substrate.

• Microbiology and Biotechnology Letters
• /
• v.33 no.2
• /
• pp.106-111
• /
• 2005

To investigate the substrate variety of a putative non-metal dependent isomerase, the tagatose-6-phosphate isomerase (E.C. 5.3.1.26) structural genes (lacB; 510bp and lacA; 430bp) of Staphylococcus aureus were subcloned and co-expressed. Based on the substrate configuration, various aldoses were surveyed for substrate of ketose isomerization. Among the 10 aldoses tested, D-ribose and D-allose were isomerized by the enzyme. The subunit A and B showed more than $95\%$ activity for D-ribose and $75\%$ for D-allose in the presence of 1mM EDTA compared with non-EDTA conditions, which implying tagatose-6-phosphate isomerase is a non-metal dependent isomerase. Each of subunit A or subunit B alone showed no activity for any of the substrates tested. The affinity constant ($K_m$) of tagatose-6-phosphate isomerase against D-ribose and D-allose were 26 mM and 142 mM, respectively.