title: Encapsulation of Beetroot Pomace Extract: RSM Optimization, Storage and Gastrointestinal Stability.
abstract: One of the great problems in food production are surplus by-products, usually utilized for feeding animals and for preparation of dietary fibre or biofuel. These products represent potential sources of bioactive antioxidants and colour-giving compounds which could be used in the pharmaceutical industry and as food additives. In the present study beetroot pomace extract was encapsulated in soy protein by a freeze drying method. Process parameters (core: wall ratio, extract concentration and mixing time) were optimized using response surface methodology (RSM) in order to obtain the optimum encapsulate (OE) with the highest polyphenol encapsulation efficiency (EE) and radical scavenging activity on DPPH radicals (SA). Using the calculated optimum conditions, the EE (86.14%) and SA (1668.37 μmol Trolox equivalents/100 g) of OE did not differ significantly (p < 0.05) from the predicted ones. The contents of total polyphenols (326.51 mg GAE/100 g), flavonoids (10.23 mg RE/100 g), and betalains (60.52 mg betanin/100 g and 61.33 mg vulgaxanthin-I/100 g), individual content of phenolic compounds and betalains by HPLC, and the ability to reduce Fe(3+) ions, i.e., reducing power (394.95 μmol Trolox equivalents/100 g) of OE were determined as well. During three months of storage at room temperature, polyphenol retention was much higher (76.67%) than for betalain pigments, betacyanins (17.77%) and betaxanthins (17.72%). In vitro digestion and release of phenolics from OE showed higher release rate in simulated intestinal fluid than in gastric fluid. These results suggest encapsulation as a contemporary method for valorisation of sensitive bioactive compounds from food industry by-products.
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, Novi Sad 21000, Serbia. vesnat@uns.ac.rs.
authors.forename: Vesna
authors.initials: V
authors.lastname: Tumbas Šaponjac
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, Novi Sad 21000, Serbia. jasnab@uns.ac.rs.
authors.forename: Jasna
authors.initials: J
authors.lastname: Čanadanović-Brunet
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, Novi Sad 21000, Serbia. cetkovic@tf.uns.ac.rs.
authors.forename: Gordana
authors.initials: G
authors.lastname: Ćetković
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, Novi Sad 21000, Serbia. jakisicmirjana@gmail.com.
authors.forename: Mirjana
authors.initials: M
authors.lastname: Jakišić
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, Novi Sad 21000, Serbia. sdjilas@tf.uns.ac.rs.
authors.forename: Sonja
authors.initials: S
authors.lastname: Djilas
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, Novi Sad 21000, Serbia. jvulic@uns.ac.rs.
authors.forename: Jelena
authors.initials: J
authors.lastname: Vulić
authors.affiliation: Faculty of Technology, University of Novi Sad, Bulevar cara Lazara 1, Novi Sad 21000, Serbia. sladja@uns.ac.rs.
authors.forename: Slađana
authors.initials: S
authors.lastname: Stajčić
mesh_terms: D027461:Beta vulgaris / Q000737:chemistry*; D050858:Betalains / Q000032:analysis; D001688:Biological Products / Q000378:metabolism; D002214:Capsules; D004339:Drug Compounding / Q000379:methods*; D004356:Drug Storage; D005419:Flavonoids / Q000032:analysis; D019649:Food Industry; D005612:Freeze Drying; D066298:In Vitro Techniques; D007413:Intestinal Mucosa / Q000378:metabolism; D010636:Phenols / Q000032:analysis; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry; D030262:Soybean Proteins / Q000378:metabolism
chemical_list: D001688:Biological Products; D002214:Capsules; D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D030262:Soybean Proteins; D050858:Betalains
keywords: RSM; beetroot; betalains; digestion; encapsulation; polyphenols; storage