Mihaela Ivanova

Encapsulation of biologically active substances and their addition in various foods represent great possibilities to obtain products with increased biological value and potential health effects. Encapsulation of chokeberry juice, rich in polyphenolic compounds and anthocyanins, beetroot extract containing betalain in alginate- inulin beads were used to obtained new functional food product. The prepared fermented dairy dessert, with added alginate-inulin beads with biologically active substances was characterized with very good organoleptic properties and represented a product containing substances with known beneficial effect on human health.

The production of functional lactic acid dairy products constantly increases nowadays. They are usually used to enrich with soluble dietary fibers that enhance their functional characteristics. The aim of the current research was to investigate the lactic acid dairy products enriched with inulin-type fructans with different degree of polymerization and to analyse the fructooligosacharides and inulin content in them after lactic acid fermentation. For the yoghurt preparation inulin and fructooligosacharides extracted from tubers of Helianthus tuberosus L. and commercially available inulin from chicory were used. The amount of fructans from inulin-type was determined by spectrophotometric, TLC and HPLC-RID methods. The results from the analysis showed that after lactic acid fermentation the content of inulin changed in a very small amount and the obtained product possessed improved healthy and potential prebiotic effect.

Lactic acid fermented dairy products are characterized with certain dietary, therapeutic and prophylactic properties. In order to increase their biological value are explored the possibilities to use fructans with different degree of polymerization (DP) fructooligosaccharides (DP = 2-7) and inulin (DP = 22 which are fractionated by Jerusalem artichoke and inulin Raftiline® HP (DP = 25) isolated from chicory. These inulin-type fructans have a prebiotic effect, and new approaches for their application in the production of fermented milk products are explored. It is traced the influence of the amount of added fructo-oligosaccharides and inulin on the process of biochemical transformation of lactose and on the texture of the product. It was found that the added dietary fiber does not affect the dynamics of the lactic acid process. The quantity of separated serum increases with the degree of polymerization of fructans and with increased amount of added inulin. Fructooligosaccharides (DP ...

Abstract Ultrasonic fractional extraction of fructooligosaccharides and inulin from Jerusalem artichoke tubers has been carried out. The following conditions as the type of the used solvent- n-propanol, 95% (v/v) ethanol and distilled water and the duration of the extraction process have been varied. The contents of sugars and fructans in the obtained extracts were determinated by spectrophotometric method based on resorcinol reaction and by TLC analysis. The greatest amounts of fructooligosaccharides and inulin have been extracted by distilled water (46 g/100g d.w.), as each ultrasonic extraction was carried out in triplicate for 30 min. The best solvent used for the separation of a particular fraction fructooligosaccharides consisting of kestose, nystose and fructofuranosylnystose was n-propanol.

A rapid and sensitive spectrophotometric method for the quantitative determination of inulin and fructooligosacharides in lactic acid fermented dairy products has been developed. The method was based on the familiar Seliwanoff reaction for detection of ketoses with resorcinol in hydrochloric acid media. The standard curve was constructed by using fructose as a standard. The tested spectrophotometric method has been characterized with good linearity (R2=0.997) in the fructose concentration range 0.5-20 μg/ml. The presence of galactose and lactose in the analyzed samples did not interfere in the determination of inulin. The sample preparation procedure included hot water extraction, purification by Carrez solutions and subsequent spectrophotometric determination at 480 nm. The developed method showed very good precision: repeatability (RSD=6%) and reproducibility (RSD=10%). The obtained results demonstrated that the spectrophotometric method is less time-consuming, cheap, reproducible and suitable for routine laboratory analysis.

Abstract: The influence of harvest time on fructan (fructooligosaccharides and inulin) content of different varieties of Helianthus tuberosus have been investigated in this study. The determination of quantity of inulin in the tubers harvested during three years period from 2010 until 2012 was done. The extraction of fructooligosacharides was carried out with 95 % (v/v) ethanol used as a solvent. Inulin from tubers of Helianthus tuberosus was extracted by treatment with hot distilled water. The extraction efficiency of inulin and fructooligosacharides was followed by TLC analysis. The fructan content in the extracts obtained from the tubers was determined by the spectrophotometric method based on the Seliwanoff reaction with resorcinol and by HPLC-RID method. It was found that a similar amount of inulin and fructooligosacharides (45-53% of dry weight) was observed in the middle early varieties harvested 21-26 weeks after plantation and in the late variety harvested 29-33 weeks after planting. From the obtained results, we can conclude that the tubers of both varieties of Helianthus tuberosus harvested in autumn 2011 contain the highest amount of fructans (50-69 % of dry weight).

Fermented dairy products from cow milk with addition of lactulose are produced, which have well known health characteristics. The dynamic of the process of lactose fermentation is investigated with addition of different amount of the disaccharide - 1, 2, and 3 % and a control sample. It is found that the dynamic of biochemical transformation of lactose to lactic acid and the coagulation of the milk in the versions with different amounts of added lactulose are similar to the control sample. The organoleptic profile of the obtained products, show that they are characterized by indicators - texture, color, taste and aroma typical for this group of products.