Progress 10/01/06 to 09/30/09
Outputs
OUTPUTS: This project collected data regarding how to use tagatose in foods. Tagatose is a non-digestible carbohydrate that has prebiotic properties, and its incorporation into foods may therefore have a positive effect on human health. However, tagatose must not break down in the food during processing or storage. Forty-eight experiments were conducted to collect data about the storage stability of tagatose in various buffer solutions at 20-40 degrees C. An additional forty-eight experiments were conducted to evaluate the thermal stability of tagatose in buffer solutions at 60-80 degrees C. Experiments on tagatose stability in two real beverages, UHT reduced-fat milk and canned light lemonade, were most recently completed. In addition, sensory studies involving bakery products with and without added tagatose were completed to evaluate consumer perception of tagatose-containing products. During the course of this project, two graduate students and an undergraduate student were mentored with respect to scientific methodology, data analysis, and dissemination of results. All participated in writing journal articles containing the outcomes. The two major ways the outcomes have been shared with interested groups are through presentations at the Institute of Food Technologists' annual meetings and journal articles. Two M.S. theses were additional outputs associated with this project. PARTICIPANTS: The project director oversaw completion of the project. He trained 2 graduate students and an undergraduate student. All individuals prepared and presented posters at professional meetings as well as participated in manuscript preparation. Through this project, the students developed many professional skills, such as research planning and organization, execution and follow-through of the plan, data analysis, scientific writing, and scientific presentations. TARGET AUDIENCES: Our audience includes members of the scientific community and food product development scientists interesting in utilizing tagatose in foods. Poster presentations and journal articles were used to disseminate information to these audiences. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The primary outcome of this research project was the new knowledge it created about the properties of tagatose, which were previously lacking. With respect to the stability, tagatose was found to break down under certain situations. Several factors influence how fast tagatose is lost. Tagatose retention in beverages is improved by avoiding phosphate buffer, elevated pH levels, and high temperatures. However, typical pasteurization conditions do not cause significant tagatose loss due to the short time of exposure at the high temperatures. Because the lemonade and milk contained little or no phosphate buffer, tagatose stability in these real beverages was quite good both during thermal processing and product storage. Therefore, tagatose stability during processing and storage should not pose major concerns if the product formulation is optimized. In addition, consumers could not differentiate between the flavor of bakery products containing up to 2% tagatose and those without tagatose. The data suggest that low levels of tagatose can be added to foods as a prebiotic with little effect on the flavor. Based on the results of this project, food manufacturers should consider adding 1-2% tagatose into their foods as a healthful prebiotic supplement.
Publications
- Armstrong, L.M., Luecke, K.J., and Bell, L.N. 2009. Consumer evaluation of bakery product flavour as affected by incorporating the prebiotic tagatose. International Journal of Food Science and Technology. 44:815-819.
- Luecke, K.J. 2009. Thermal stability of tagatose in solution. M.S. thesis. Auburn University, Auburn, AL.
- Luecke, K. and Bell, L. 2009. Thermal stability of tagatose in solution. 2009 IFT Annual Meeting & Food Expo Technical Program: Book of Abstracts. Institute of Food Technologists, Chicago, IL, p. 84
- Dobbs, C.M. and Bell, L.N. 2010. Storage stability of tagatose in buffer solutions of various compositions. Food Research International. 43:382-386.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: This project has been investigating how to use tagatose, a prebiotic carbohydrate, in foods. One aspect this project evaluated was the effect of composition and processing temperatures on tagatose stability in beverage-like products. Tagatose loss during thermal processing would reduce its beneficial health effects. The major outputs this year were the experiments conducted at high temperatures to evaluate the effects of pH, buffer type, buffer concentration, and added amino acids on tagatose stability. Forty experimental solutions were prepared and analyzed over time to evaluate tagatose loss. During the course of these experiments, two graduate students were mentored with respect to experimental methodologies, including sample preparation, data acquisition, data analysis, and dissemination of outcomes. Thus, this project has helped develop their research and writing skills. Another component of this year's research evaluated how incorporating 1 and 2% tagatose into bakery products affected their flavors. Outputs included the twelve sensory tests that evaluated flavor differences and acceptability between tagatose-containing products and control products. An undergraduate student gained valuable experience by helping to design and conduct the experiment as well as present the data. PARTICIPANTS: The project director aided in sample preparation, trained a graduate student and undergraduate student, analyzed some samples, helped conduct sensory studies, evaluated data, and supervised data dissemination. One graduate student prepared experimental solutions, performed sample analysis, and collected data. Another graduate student completed a poster, thesis, and manuscript draft about the storage stability of tagatose in solutions. An undergraduate student (not salaried on this project) conducted the sensory studies, prepared a poster, and drafted a manuscript. TARGET AUDIENCES: Our audiences include members of the scientific community and food product development scientists interested in exploring ways of incorporating tagatose into food and beverage systems. Two poster presentations (with published abstracts) containing data about tagatose stability and flavor were presented at the 2008 annual meeting of the Institute of Food Technologists in New Orleans, Louisiana. Another presentation was made at the Auburn University Undergraduate Research Forum. One M.S. thesis was completed and one journal article published. PROJECT MODIFICATIONS: The general scope of this project remains the same as stated in the grant application. One minor alteration was the abandonment of apple juice as a system for evaluating tagatose stability because of fructose interfering with the analysis methodology. Apple juice was replaced by a diet lemonade beverage, which is also an acidic beverage product.
Impacts
With respect to the stability of tagatose during thermal processing, results indicate that certain environmental parameters enhance tagatose loss. Phosphate buffer, especially at higher concentrations, causes a greater loss of tagatose than citrate buffer. The degradation is faster at pH 7 than pH 3. Tagatose was breaking down in basic experimental solutions containing only tagatose and the buffer salts. The addition of the amino acid glycine, for the most part, did not enhance tagatose loss, which was unexpected. The loss of tagatose is also accompanied by a darkening of the solutions. Activation energies were used to predict the loss that would occur under typical pasteurization conditions. Although loss is occurring, during the relatively short thermal processing times required for pasteurization, less than 0.5% tagatose would be lost. This knowledge with respect to tagatose's behavior in solution has not been reported previously. In the other study, muffins, cookies, and cupcakes were prepared to contain 1% or 2% tagatose. Sensory evaluations were conducted to compare these products to a control product not containing tagatose. Sensory panelists could not tell the difference between products containing tagatose and not containing tagatose. In addition, the consumer panel liked products with and without tagatose equally. Therefore, 1 and 2% tagatose can be incorporated into bakery products without harming their flavor while providing the prebiotic effect to consumers. Based on the data collected this year, the production of tagatose-containing food products appears feasible, which would deliver its prebiotic benefit to consumers.
Publications
- Taylor, T.P, Fasina, O., and Bell, L.N. 2008. Physical properties and consumer liking of cookies prepared by replacing sucrose with tagatose. Journal of Food Science, 73(3): S145-S151.
- Dobbs, C. and Bell, L. 2008. Storage stability of tagatose, a prebiotic monosaccharide, in solutions (#007-03). 2008 IFT Annual Meeting Scientific Program Book of Abstracts. Institute of Food Technologists, Chicago, IL, p. 17.
- Armstrong, L. and Bell, L. 2008. Evaluation of the flavor-enhancing properties of tagatose in bakery products (#173-01). 2008 IFT Annual Meeting Scientific Program Book of Abstracts. Institute of Food Technologists, Chicago, IL, p. 213.
- Dobbs, C.M. 2008. Storage Stability of Tagatose in Buffer Solutions of Various Composition. M.S. thesis. Auburn University, Auburn, AL, available at http://graduate.auburn.edu/fpdb/AUETD/Dobbs_Cathleen_24.pdf.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: This project involves studying the utilization of the prebiotic tagatose as a food ingredient. One aspect of this project was to determine how food composition and storage temperature affect the stability of tagatose in beverage-like solutions. The degradation of tagatose would reduce its beneficial health effects. The major outputs thus far are the experiments conducted to evaluate the effects of pH, buffer type and concentration, added amino acids, and temperature on tagatose stability. Forty-eight experimental solutions have been prepared, and aliquots have been analyzed periodically for almost 9 months to determine the amount of tagatose remaining. During the course of these experiments, a graduate student has been mentored with respect to experimental methodologies, including sample preparation, data acquisition, and data analysis. Thus, this project has helped develop her research skills in the laboratory. Another component of this project is to evaluate the effects of
incorporating tagatose into foods on their physical and sensory properties. The effects of tagatose on the physical properties of cookie dough and baked cookies were reported last year. The sensory properties of cookies, where different amounts of sucrose were replaced by tagatose, are reported this year. An individual formerly supported by this project gained additional writing experience by helping prepare a poster and manuscript.
PARTICIPANTS: The project director aided in the preparation of the experimental solutions, trained a graduate student, analyzed some samples, is monitoring the data as it is being collected, organized the poster presentation, and directed the preparation of a manuscript. One graduate student also aided in the preparation of the experimental solutions, performed sample analysis, and collected data. A former student (no longer salaried) completed a poster and manuscript about tagatose as a sugar replacer in cookies.
TARGET AUDIENCES: Our audiences include members of the scientific community and food product development scientists interested in exploring ways of incorporating tagatose into the food system. A poster containing data about tagatose usage in cookies (physical and sensory properties) was presented at the 2007 annual meeting of the Institute of Food Technologists.
PROJECT MODIFICATIONS: The general scope of this project remains the same as stated in the research proposal. One issue we will need to address is that during our method development, fructose and tagatose appear to co-elute from the HPLC, which means we will have difficulty analyzing tagatose in apple juice as initially planned. During the coming year we will evaluate more thoroughly our HPLC method for separating tagatose from the components in apple juice, but may need to switch to another beverage. In addition, because a total substitution of tagatose for the sucrose in bakery products appears problematic, we may shift attention toward the effects of lower amounts of tagatose on the sensory properties of bakery products.
Impacts
With respect to tagatose stability, results indicate that certain parameters enhance the degradation of tagatose. Phosphate buffer, especially at higher concentrations, causes a greater loss of tagatose than citrate buffer. The degradation is faster at pH 7 than pH 3. In all these cases, the basic experimental solutions contain only tagatose and the buffer salts dissolved in water; yet, tagatose is being lost and the solution is darkening. The addition of the amino acid glycine also influences the loss of tagatose, but its exact extent relative to the solutions without glycine is still being evaluated. The loss of tagatose is also accompanied by a darkening of the solutions. This knowledge with respect to tagatose's behavior in solution has not been reported previously. In addition, cookies prepared by replacing all of the sucrose with tagatose were found to be less acceptable by a sensory panel than cookies prepared with sucrose. However, by replacing only 50% of the
sucrose with tagatose, panelists' overall acceptability rankings were not significantly different from the all sucrose cookie. Therefore, tagatose may be used to partially replace sucrose in cookies, a result which has also not been reported previously. Based on stability and behavior, there seems a good likelihood that low levels of tagatose could be successfully incorporated into foods to deliver its prebiotic effect
Publications
- Taylor, T., Fasina, O., and Bell, L. 2007. Tagatose, a prebiotic monosaccharide, as a sugar substitute in cookies. 2007 IFT Annual Meeting Technical Program Abstracts. IFT: Chicago, IL. p. 42.
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Progress 10/01/06 to 12/31/06
Outputs
Tagatose is a sugar that is not metabolized directly by the body. Tagatose is fermented in the intestinal tract into short chain fatty acids; it therefore behaves as a prebiotic, improving intestinal health. However, its utilization in food has not been widely explored. The purpose of this initial project was to investigate whether tagatose could be successfully used as a sugar-replacer in cookies. Various cookie formulations were prepared, and the textural properties of their doughs were evaluated, including hardness, adhesiveness, springiness, cohesiveness, chewiness, and resilience. Replacing all the sucrose with tagatose (i.e., 100% substitution) resulted in no significant change (p<0.05) to any of these textural characteristics. However, when a blend of 50% sucrose and 50% tagatose was used in the cookie dough, it became softer and springier than that containing only sucrose. A softer dough may require less energy to mix, resulting in potential savings for the
manufacturer. Upon baking, the cookies containing tagatose were darker in color than those made with sucrose. Tagatose is a reducing-sugar and as such will participate more actively in the Maillard reaction (i.e., nonenzymatic browning) than sucrose. As the concentration of tagatose increased within the cookie, the snap force also increased. Cookies prepared with 75% or 100% tagatose were significantly harder than cookies prepared with sucrose alone. The spread ratio (i.e., diameter/height) decreased as the amount of tagatose increased meaning the cookies were taller, but less wide. In cookie formulations, a ratio of approximately 50% tagatose and 50% sucrose appears to optimize both the properties of the dough and baked product.
Impacts
Food manufacturers may be able to reduce the amount of digestible sugars in cookies by replacing part of the sucrose with tagatose. In addition, the prebiotic effect from making this substitution would improve intestinal health. Together, the lower digestible sugars and prebiotic effect achieved by using some tagatose would provide consumers with a more healthful cookie.
Publications
- Taylor, Tanya P. 2006. Evaluation of the bulk sweetener D-tagatose and the high intensity sweetener Splenda as sugar replacers in cookies. Ph.D. dissertation. Auburn University, Auburn, AL.
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