Extrusion cooking technology was applied for obtaining corn extrudates fortifi ed with various level (10-20%) of rosehip pomace powder or apple pomace powder. The total polyphenols content, antioxidant activities (ABTS), organoleptic properties and colour of the extrudates were determined. Pomace addition increased the level of total polyphenols content and antioxidant activity in obtained corn -pomace extrudates, especially in samples enriched with rosehip pomace. Extrudates with 20% of rosehip pomace addition characterized the highest polyphenols content and antioxidant activity. Only the slight decrease of some quality features -shape and size, taste and fl avour, structure and colour of obtained extrudates was observed. Sample with fruit pomace addition showed increasing consistency evaluation. The extruded products by utilising fruit by-products got good evaluation of panelists and can be an excellent source of bioactive compounds in the daily human diet.
S u m m a r y Nowadays, esters of saccharides and fatty acids are obtained mainly using chemical methods. An alternative method of saccharide esterification with fatty acids is a process using a lipase biocatalyst. The objective of the study was to develop a method to enzymatically esterify starch with a lipase preparation isolated from the Candida antarctica yeast. The esterification reaction of starch was performed at a low temperature (60 ºC) using non-toxic reagents. The reaction medium was also non-toxic. The obtained product of this reaction was a starch oleate that could be a thickening agents' constituent owing to its hydrophilic and hydrophobic properties. The starch ester obtained through the enzymatic esterification reaction was analysed using a HNMR (Nuclear Magnetic Resonance) technique. The degree of substituting starch with oleic acid was DS = 0.13. The DSC (Differential Scanning Calorimeter) analysis proved that the enzymatic modification of starch caused the thermal characteristics of the product obtained to change. The heat appearing specific for the starch oleate phase transition was three times lower than that of the native starch. The correlation was also determined between rheological properties of water suspensions of starch and starch oleate and temperature. The starch oleate was characterized by a rapid increase in its viscosity during the initial phase of heating and, as the temperature rose, by a slow decrease in its viscosity.
W niniejszej pracy przeprowadzono enzymatyczną estryfikację skrobi niskoacetylowanej kwasem tłuszczowym z użyciem enzymów w środowisku rozpuszczalnika organicznego. Analizom zostały poddane zarówno substancje wyjściowe jak i produkty powstałe w reakcji estryfikacji. W wyniku reakcji estryfikacji przy zastosowaniu lipazy z drożdży Candida antarctica oraz dwóch wyodrębnionych na drodze przemysłowej frakcji tego enzymu (A i B) powstały 3 estry skrobi acetylowanej i kwasu oleinowego Ich stopień podstawienia oznaczony za pomocą analizy spektrum 1HNMR wynosił od 0,07 do 0,12 i był zależny od frakcji zastosowanego enzymu. Analiza termiczna przy użyciu różnicowego kalorymetru skaningowego wykazała, że ciepło właściwe przemiany fazowej produktów estryfikacji było wyższe niż ciepło właściwe przemiany fazowej skrobi acetylowanych. Istotny wpływ na zbadane właściwości fizyczne otrzymanych związków miał stopień acetylacji skrobi.
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