(434e) Study for Galacto-Oligosaccharides Production Using Supercritical Fluid Extraction Technology

                                                    Study for Galacto-oligosaccharides Production using Supercritical Fluid Extraction Technology

                                                                       F. Montañés¹, T.Fornari², A. Olano² and E. Ibáñez²

¹Integrated Bioactive Technologies, Industrial Research Limited. 69 Gracefield Road, 5040 Lower Hutt, New Zealand

²Instituto de Investigación en Ciencias de la Alimentación, C/ Nicolás Cabrera 9, Campus de Cantoblanco, 28049 Madrid, Spain

Corresponding author: f.montanes@irl.cri.nz; Phone: (+64) 049313342; Fax: (+64) 04 566 6004

Prebiotic carbohydrates, as defined by Gibson and Roberfroid in 1995, are “Non digestible carbohydrates that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improve host health”. Among the prebiotic carbohydrates special attention has been put on galacto-oligosaccharides (GOS) which are commonly synthesized from cheese permeate and other lactose-rich streams by a transgalactosylation reaction catalyzed by the enzyme β-  galactosidase (EC 3.2.1.23 from International Union of Biochemistry  and Molecular Biology nomenclature recommendation) from different sources.

GOS provide several health benefits, which make their use as food ingredients particularly attractive: (1) reduction of detrimental bacteria; (2) production of nutrients; (3) increase in absorption of different minerals in the intestine; (4) prevention of pathogenic and autogenic diarrhea; (5) prevention of constipation; (6) reduction in serum cholesterol; (7) reduction of blood pressure; and (8) anticancer effect, mainly the gut cancer.

The separation of carbohydrates plays an important role in food production and in cosmetic and pharmaceutical industries, accounting for around 90% of the cost in food production. GOS are especially suitable in food products for special target groups, such as infant nutrition, clinical nutrition and foods for elderly people. GOS are available as powders or syrups, typically with about 75% solids, of which GOS comprise about 55–60%, lactose 20%, glucose 20% and galactose between 1 and 5%.

Food-grade complex oligosaccharide mixtures manufactured commercially via transglycosylase reactions using disaccharides such as lactose as the raw material are, in general, not pure products. Reducing oligosaccharides may be isomerized using borates and aluminates as complexating agents to obtain prebiotic oligosaccharides. Aluminates and borates agents are used to avoid side reactions but are difficult to remove from the mixture.

This raw material, where GOS are produced, is largely available on the market (Lactoserum as by-product of the cheese and casein manufacture). According with Aider et al, annual whey production in the world is estimated to be 72 million tons, which means that about 1.2 million tons is transferred into whey annually. Even though the utilization of this resource has been changing the perception from a “waste material” to an “opportunity” for further processing, utilization or disposal of whey remains one of the most significant problem in the industry. According with the “Global Opportunities for Whey and Lactose Ingredients 2010-2014”, lactose, pharmaceutical lactose and lactose derivatives (which one is GOS) are worth more than USD 1.6 billion in 2010, whereas market value is estimated to nearly USD 2 billion in 2014 resulting in a CAGR (compound annual growth rate) of 3%. For the period 2006-2010, GOS grew annually by an impressing 15% compared, for example, with lactulose increasing a mere one to four per cent annually.

As abovementioned, the main problem for GOS production is purification. GOS commercially available contain important quantities of lactose and glucose that reduce greatly the scope of potential users. These products are not suitable for lactose intolerant and diabetic consumers. The goals of this study are: 1) obtain a wide potential use GOS mixture using first transglycosilation reaction and second an isomerization reaction using borates and aluminates separately; 2) fractionation and purification of GOS mixture using supercritical fluid technology. Not only purification of carbohydrates, but also removal of complexating agents was pursued; and 3) cost estimation for supercritical fractionation purification process of GOS mixtures in order to compare with industrial available processes and study the feasibility of the laboratory scale process developed. The simulation process was carried out using AspenONE V7.2 software from AspenTech.

A wide range of experimental conditions were studied in steps 1 and 2 in order to obtain a complete outlook of the situation. We combined all this experimental work with our background in the carbohydrate purification and fractionation using supercritical fluid technology in order to achieve our goal. Finally, experimental conditions for goals 1 and 2 were established and simulation process were run.

ACKNOWLEDGMENTS

This work has been financed under a Project Consolider Ingenio 2010 FUN-C-FOOD program (CSD2007-00063) and of the Comunidad Autónoma de Madrid (S-0505/AGR/000153). F.M. thanks MEC for a FPI grant. T. F. would like to acknowledge the financial support of the Ramon y Cajal Program from the Ministry of Education and Science.