Utjecaj veličine čestica posija prosa i njihove prethodne obrade ksilanazom na fizikalna, senzorska i nutritivna svojstva bezglutenskog kruha

Research background. Millet bran is a by-product rich in dietary fibre, micronutrients and bioactive compounds which are often deficient in a gluten-free diet. Previously, cryogenic grinding has been shown to improve the functionality of bran to some extent, although it offered limited benefits for bread making. This study aims to investigate the effects of adding proso millet bran depending on its particle size and xylanase pretreatment on the physicochemical, sensory and nutritional properties of gluten-free pan bread. Experimental approach. Coarse bran (d50=223 μm) was ground to medium size (d50=157 μm) using an ultracentrifugal mill or to superfine particles (d50=8 μm) using a cryomill. Millet bran presoaked in water (for 16 h at 55 °C) with or without the addition of fungal xylanase (10 U/g) replaced 10% of the rice flour in the control bread. Bread specific volume, crumb texture, colour and viscosity were measured instrumentally. Along with proximate composition, the content of soluble and insoluble fibre, total phenolic compounds (TPC) and phenolic acids as well as total and bioaccessible minerals of bread were assessed. Sensory analysis of the bread samples included a descriptive, hedonic and ranking test. Results and conclusions. Dietary fibre content (7.3-8.6 g/100 g) and TPC (42-57 mg/100 g) on dry mass basis of the bread loaves depended on bran particle size and xylanase pretreatment. The effect of xylanase pretreatment was most evident in the loaves with medium bran size in terms of higher content of fibre soluble in ethanol (45%) and free ferulic acid content (5%), improved bread volume (6%), crumb softness (16%) and elasticity (7%), but lower chewiness (15%) and viscosity (20-32%). Bread bitterness and dark colour were increased after adding medium-sized bran but its bitter aftertaste, crust crookedness, crumb hardness and graininess were reduced with xylanase pretreatment. Although bran addition impaired protein digestibility, it enriched the bread with iron (341%), magnesium (74%), copper (56%) and zinc (7.5%). Xylanase pretreatment of the bran resulted in the improved bioaccessibility of zinc and copper of the enriched bread compared to the control and bread without xylanase. Novelty and scientific contribution. Application of xylanase to medium sized bran obtained by ultracentrifugal grinding was more successful than its application to superfine bran obtained by the multistage cryogrinding as it resulted in more soluble fibre in gluten-free bread. Moreover, xylanase was proven beneficial in maintaining desirable bread sensory properties and mineral bioaccessibility.Pozadina istraživanja. Posije prosa su nusproizvod bogat prehrambenim vlaknima, mikronutrijentima i bioaktivnim spojevima, kojih često nema dovoljno u bezglutenskoj prehrani. Prethodna su istraživanja pokazala da kriogeno mljevenje u određenoj mjeri poboljšava funkcionalnost posija, iako su njegove prednosti u izradi kruha bile ograničene. Svrha je ovoga rada bila istražiti učinak veličine čestica posija prosa i njihove prethodne obrade ksilanazom na fizikalno-kemijska, senzorska i nutritivna svojstva bezglutenskog kruha. Eksperimentalni pristup. Krupne posije (d50=223 μm) samljevene su do srednje veličine (d50=157 μm) pomoću ultracentrifugalnog mlina, ili do vrlo finih čestica (d50=8 μm) pomoću kriomlina. Posijama prosa prethodno namočenih u vodi (16 sati na 55 °C) s dodatkom fungalne ksilanaze (10 U/g) ili bez nje zamijenjeno je 10 % rižinog brašna u kontrolnom kruhu. Specifični volumen, tekstura sredine, boja i viskoznost kruha određeni su instrumentalno. Uz kemijski sastav, određeni su udjeli topljivih i netopljivih vlakana, ukupnih fenolnih spojeva i fenolnih kiselina te ukupnih i biološki dostupnih mineralnih tvari u kruhu. Senzorska analiza uzoraka kruha uključivala je deskriptivni i hedonistički test, te test rangiranja. Rezultati i zaključci. Sadržaj prehrambenih vlakana (7,3–8,6 g/100 g) i ukupnih fenolnih spojeva (42–57 mg/100 g) u suhoj tvari kruha ovisio je o veličini čestica posija i prethodnoj obradi ksilanazom. Učinak prethodne obrade ksilanazom bio je najočitiji u kruhu s posijama srednje veličine čestica, koji je imao veće udjele vlakana topljivih u etanolu (45 %) i slobodne ferulinske kiseline (5 %), veći volumen (6 %), mekoću (16 %) i elastičnost sredine (7 %), te smanjenu žvakljivost (15 %) i viskoznost (20-32 %). Gorčina i tamna boja kruha su se povećale dodatkom posija srednje veličine, ali njegov gorak okus, popucanost kore, tvrdoća sredine i zrnatost smanjeni su prethodnom obradom ksilanazom. Iako je dodatak posija smanjio probavljivost proteina, obogatio je kruh željezom (341 %), magnezijem (74 %), bakrom (56 %) i cinkom (7,5 %). Prethodna obrada posija ksilanazom rezultirala je poboljšanom biološkom dostupnošću cinka i bakra u obogaćenom kruhu, u usporedbi s kontrolnim uzorkom i kruhom dobivenim bez prethodne obrade posija ksilanazom. Novina i znanstveni doprinos. Prethodna obrada ksilanazom imala je veći učinak na posije srednje veličine dobivenim ultracentrifugalnim mljevenjem, nego na vrlo fine posije dobivene višestrukim kriomljevenjem, jer je povećala udjel topljivih vlakana u bezglutenskom kruhu. Nadalje, obrada ksilanazom bila je korisna za zadržavanje poželjnih senzorskih svojstava kruha i biološke dostupnosti mineralnih tvari

Quality assessment of 3D-printed cereal-based products

The process of three-dimensional (3D) printing is of greatest interest to food science and engineering community because it offers numerous opportunities for innovative food design, new product formulations and personalized nutrition. Of particular interest are food inks based on cereal flours or starches, whose unique rheological properties make them suitable for 3D printing, typically with an extrusion-based printer. While the factors that influence the success of food printing are well addressed, the terminology and methods used to evaluate the process and product features are miscellaneous. Therefore, this research work aims at providing an overview of the most commonly used parameters and methods for evaluation of the extrusion-based 3D printing process and the resulting cereal-based foods. Physical and sensory methods that are successfully used for the quality assessment of the ink and the printed raw objects, as well as the post-processed products are here reviewed and outlined. The properties of inks, usually determined with dynamic rheological tests, are linked to various aspects of printing quality whereas the physical properties of printed raw forms are usually evaluated by image analysis combined with mathematical calculations. Microscopy analysis is undertaken to study the microstructure of both the raw objects and the end-products, while texture analysis and sensory evaluation of final product are performed both by a panel and instrumentally. We provide details of the tests, but also emphasize the need to standardize the procedures and terminology in order to avoid misunderstandings and multiple variations of similar methods. This review provides a basis for further development and standardization of the methodology for quality assessment of 3D-printed cereal-based foods.info:eu-repo/semantics/publishedVersio

Fermentacija kiselog tijesta pripremljenog s rogačevim brašnom i njegova primjena u proizvodnji pšeničnog kruha

Carob is widely cultivated Mediterranean plant, but its flour is scarcely used in bread making. Previous studies investigated the quality of wheat bread with added carob flour showing discrepant results. This study aims to investigate the fermentation performance, antioxidant activity, rheological behaviour and baking application of carob sourdough. Carob sourdough was fermented with Lactobacillus brevis or Lactobacillus fermentum combined with Saccharomyces cerevisiae for 24 h at 30 °C. At the end of sourdough fermentation, number of viable lactic acid bacteria and yeast cells, total titratable acidity, pH value, antioxidant activity, phenolics and sugar content were determined. Carob flour (12% flour mass fraction) or sourdough equivalent (22.5% dough mass fraction) was applied in making composite partially baked frozen bread. Dough rheology was monitored using a farinograph. Nutritive value, physical properties and sensory attributes of the rebaked bread samples were evaluated using a hedonic test. By the end of fermentation, carob sourdough reached pH=4.2-4.5 and total acidity 9.9-12.3 mL of 0.1 M NaOH, sugar content on dry mass basis was reduced by 8 g/100 g, while total phenolics and antioxidant activity were increased up to 21%, depending on the starter culture. Addition of carob flour or sourdough to wheat dough resulted in firmer consistency, longer development time, and lower quality number. Regardless, bread with carob flour had significantly improved specific volume. Compared with common wheat bread, carob bread had increased dietary fibre content (46%), total phenolics (140-200%) and antioxidant activity (240-300%), higher shape, larger volume, reduced crumbliness, unchanged firmness and darker crumb colour. Consumer preference and overall acceptability scores of carob sour bread were comparable to those of wheat bread, falling into the category of ’liking very much’. To our knowledge, this is the first study that proved the feasibility of carob sourdough fermentation using mixed starter cultures, where L. brevis together with S. cerevisiae was better adapted to the substrate than L. fermentum. The carob sourdough could be used as a natural ingredient for improvement of nutritive value and reduction of crumbliness of partially baked frozen bread.Pozadina istraživanja. Rogač je biljka koja se uzgaja diljem Mediterana, ali se njegovo brašno rijetko koristi u proizvodnji kruha. U prethodnim je istraživanjima ispitana kakvoća pšeničnog kruha s dodatkom rogačevog brašna, ali su dobiveni kontradiktorni rezultati. Svrha je ovog istraživanja bila ispitati fermentaciju rogačevog kiselog tijesta, njegovu antioksidacijsku aktivnost i reološka svojstva, te mogućnost njegove primjene u proizvodnji kruha. Eksperimentalni pristup. Rogačevo kiselo tijesto fermentirano je s kombinacijom bakterija Lactobacillus brevis ili Lactobacillus fermentum i Saccharomyces cerevisiae tijekom 24 h na 30 °C. Pri završetku fermentacije određeni su sljedeći parametri: broj živih stanica bakterija mliječne kiseline i kvasca, ukupna titracijska kiselost, pH-vrijednost, antioksidacijska aktivnost te udjeli fenolnih spojeva i šećera u kiselom tijestu. Rogačevo brašno (12 % masenog udjela brašna) ili ekvivalent kiselog tijesta (22,5 % masenog udjela tijesta) korišteni su u izradi miješanog polupečenog smrznutog kruha. Reološka svojstva tijesta praćena su pomoću farinografa. Dopečenim uzorcima kruha određeni su: hranjiva vrijednost, fizikalna svojstva, te senzorska svojstva pomoću hedonističkog testa. Rezultati i zaključci. Pri kraju fermentacije rogačevog kiselog tijesta postignuta je pH-vrijednost od 4,2 do 4,5; ukupna kiselost od 9,9 do 12,3 mL 0,1 M NaOH; smanjen je udjel šećera za 8 g/100 g suhe tvari, dok su se udjel fenolnih spojeva i antioksidacijska aktivnost povećali do 21 %, ovisno o korištenoj starter kulturi. Dodatkom rogačevog brašna ili kiselog tijesta u pšenično tijesto dobiveno je tijesto čvršće konzistencije, s duljim vremenom razvoja i manjim kvalitetnim brojem. Unatoč tome, kruh s rogačevim brašnom imao je bitno veći specifični volumen. U usporedbi sa pšeničnim kruhom, rogačev kruh imao je veći udjel prehrambenih vlakana (46 %) i ukupnih fenolnih spojeva (140-200 %), te veću antioksidacijsku aktivnost (240-300 %), zatim je bio višeg oblika, većeg volumena, manje mrvljiv, dok je čvrstoća sredine bila nepromijenjena, a boja kruha tamnija. Preferencije i prihvatljivost rogačevog kiselog kruha kod potrošača bile su usporedive sa pšeničnim kruhom, odnosno u kategoriji ’vrlo mi se sviđa’. Novina i znanstveni doprinos. Prema našim spoznajama, ovo je prvo istraživanje koje je dokazalo mogućnost fermentacije rogačevog kiselog tijesta s pomoću miješanih starter kultura, pri čemu je kombinacija L. brevis i S. cerevisiae bila bolje prilagođena supstratu od kombinacije s L. fermentum. Rogačevo kiselo tijesto moglo bi se koristiti kao prirodni sastojak za poboljšanje hranjive vrijednosti i smanjenje mrvljivosti polupečenog smrznutog kruha

Optimization of High Intensity Ultrasound Treatment of Proso Millet Bran to Improve Physical and Nutritional Quality

Proso je nedovoljno iskorištena žitarica, s obzirom na njegovu hranjivu vrijednost i otpornost na nepovoljne klimatske uvjete. Hranjivi nusproizvodi meljave prosa mogu se upotrijebiti kao sirovine za dobivanje obogaćenih proizvoda od žitarica, no to zahtijeva prethodnu obradu radi poboljšanja fizikalnih svojstava i prehrambene vrijednosti. Stoga smo ispitali mogućnost primjene ultrazvuka visokog intenziteta za prethodnu obradu prosa radi povećanja udjela bioaktivnih sastojaka. Osim toga, ispitali smo utjecaj ultrazvuka visokog intenziteta na enzimsko posmeđivanje, sposobnost upijanja vode, te probavljivost proteina prosa, važnih za uporabu posija u pekarskoj i tjesteničarskoj industriji. Ultrazvučnom sondom od 400 W tretirana je 15 %-tna suspenzija prosenih posija u vodi tijekom 5, 12,5 i 20 minuta pri amplitudi od 60, 80 i 100 %. Tretman prosenih posija ultrazvukom visokog intenziteta tijekom 12,5 minuta pri amplitudi od 80 % imao je najveći utjecaj na nutritivnu vrijednost, te je uzrokovao povećanje antioksidacijske aktivnosti mjerene FRAP testom za 15 % (p<0,05) i udjela slobodnih ukupnih fenolnih spojeva za 16 % (p<0,05). Utjecaj ultrazvuka na povećanje udjela vlakana topljivih u vodi ali netopljivih u etanolu bio je vidljiv samo nakon obrade pri amplitudi od 100 % tijekom 20 minuta, te je ono iznosilo 38 %. Obrada suspenzije posija ultrazvukom pri amplitudi od 100 % tijekom 5 minuta uzrokovala je najveće povećanje sposobnosti upijanja vode, uz ograničeno posmeđivanje uzorka. Ultrazvuk visokog intenziteta aktivirao je polifenolnu oksidazu, neovisno o zagrijavanju uzorka. Zbog mogućeg negativnog utjecaja ultrazvuka visokog intenziteta na svojstva prosenih posija provedeno je optimiranje postupka, pri čemu je utvrđeno da je optimalna prethodna obrada 15 %-tne suspenzije prosenih posija u vodi bila ona pri amplitudi od 100 % tijekom 9,3 minutaMillet is an unexploited cereal with potential in the food industry due to its nutritional value and resistance to harsh climate conditions. Nutritious millet byproducts have a potential application in the development of functional cereal products, but require processing in order to improve their physical and nutritional quality. Therefore, we investigated high intensity ultrasound as a pretreatment to increase the amount of freely available bioactives from proso millet bran. We also analysed the effect of high intensity ultrasound on enzymatic browning, water retention and protein digestibility, which are crucial for the utilization in the bakery and pasta industry. A 15 % millet bran suspension in water was treated with 400-W ultrasound probe for 5, 12.5 or 20 min, with the 60, 80 or 100 % amplitude. High intensity ultrasound treatment with 80 % amplitude for 12.5 min improved most significantly the nutritive value; the antioxidant activity measured by FRAP test increased by 15 % (p<0.05), and total phenolic content by 16 % (p<0.05). Still, the impact on the increase of water-soluble and ethanol-insoluble dietary fibre by 38 % was evident after the treatment for 20 min at 100 % amplitude. High intensity ultrasound treatment at 100 % amplitude for 5 min caused the largest improvements in water retention and limited browning of the sample. High intensity ultrasound treatment activated polyphenol oxidase, regardless of the applied heating of the sample. Due to its ambiguous impact on proso millet bran characteristics, the treatment required an optimization, which showed that the optimal pretreatment of a 15 % millet bran suspension in water is at 100 % amplitude for 9.3 min

Frozen stored barley sourdough: stability and application to wheat bread

The primary aim of the industrial use of sourdough is to improve bread quality and to replace additives. This study investigates the applicability of frozen stored barley sourdough in wheat bread. Sourdough was fermented with Weissella cibaria in the presence of sucrose and xylanase, and stored frozen for 4, 8, or 12 weeks. During storage, the number of viable cells in the sourdough declined. Softer dough and crumb were obtained after the sourdough was stored for a longer period (4 weeks), while bread specific volume was unaffected by the sourdough storage time. The highest bread specific volume, shape, crumb softness, and sensory liking were obtained with 20% of the sourdough. This study demonstrates the possibility for the industrial application of frozen barley sourdough, since it can improve the quality of bread compared to the native barley flour

Bioactives in organic and conventional milled cereal products from Croatian market

A need for food that contributes to individual nutrition and health status, and also to the sustainability of the planet, is rising as a consequence of consumer’s awareness of foods nutritional value and origin. This behaviour is mostly expressed through the preference toward organically grown and wholesome food. Science to some extent supports this preference, giving more evidence supporting the benefit of whole food, and indicating that organic might be more nutritious than conventional. However, the question that remains is - is it always better? Thus in this study organic and conventional cereal milling products from Croatian market were randomly selected (namely wheat bran, whole grain, semi-white and white wheat flour, and whole grain corn, oat and rye flour) in order to determine their antioxidant activity (AO), lignans, ferulic acid (FA), total phenolic (TPC) and dietary fibre (DF) content. The research aimed to point out how cereals contribute to the diet with their fibres and bioactives, and to see to what extent consumers can expect organic cereal products to be better source of bioactives than conventional ones when buying from the market. Wheat bran distinguished among chosen products with its high FA, TPC, lignan content, and the strongest AO, especially in case of organic bran. Within whole grains organic corn flour exhibited the strongest AO and the highest TPC (2576 mg FAE kg-1), while organic oat flour was the most abundant in lignans (10064 μg kg-1). Higher content of FA, TPC, and lignans in organic wheat bran and established difference in bioactives between flours from the organic farming compared to conventional do not lead to firm conclusion that consumers can expect organically produced cereals to be superior in all nutrition aspects to conventional, as is often believed. Despite that, interestingly, among analysed nutritional parameters lignans were in all cases higher in organic products and less strong correlated to fibre content, indicating that they could be influenced by farming system. Obtained data highlight the benefit of consuming different wholegrain cereals as an important source of fibres and bioactive compounds, which, with the exception of lignans, are strongly positively correlated to the insoluble fibre content

Influence of Barley Sourdough and Vacuum Cooling on Shelf Life Quality of Partially Baked Bread

Potaknuti nastojanjima industrije da zadovolji potrebe potrošača za svježe pečenim, raznolikim i kvalitetnim pekarskim proizvodima istražili smo utjecaj dodatka ječmenog kiselog tijesta i vakuumskog hlađenja na kakvoću polupečenog kruha pakiranog u modificiranoj atmosferi tijekom skladištenja pri sobnim uvjetima. Ječmeno kiselo tijesto fermentirano je s pomoću bakterije Lactobacillus reuteri (DSM 20016, F275). Polupečeni kruh s dodanim kiselim tijestom bio je mikrobiološki ispravan sve do tridesetog dana skladištenja, dok je na kruhu bez dodatka kiselog tijesta plijesan bila vidljiva na trideseti dan skladištenja. Udjel vlage, fizikalna i senzorska svojstva određeni su nakon dodatnog pečenja polupečenog kruha, i to nakon 1, 8, 15, 22 i 30 dana skladištenja. Na petnaesti dan skladištenja zabilježen je gubitak vlage (5 %), nakon čega je udjel vlage ostao nepromijenjen do kraja ispitivanog vremena. Tijekom skladištenja došlo je do kontinuiranog smanjenja teksturalne kvalitete kruha, uslijed stvrdnjavanja sredine, dok se njegov okus i miris nisu promijenili sve do pojave plijesni. Analizom glavnih komponenata utvrđene su glavne razlike u okusu i mirisu analiziranog kiselog i kontrolnog kruha, kao i u tvrdoći sredine i udjelu vlage. Rezultati ovog istraživanja pokazuju pozitivan utjecaj dodatka ječmenog kiselog tijesta fermentiranog s pomoću L. reuteri na kakvoću polupečenog kruha, naročito na mekšu teksturu sredine kruha tijekom barem 15 dana skladištenja i sprečavanje porasta plijesni i bakterija tijekom 30 dana. Proces vakuumskog hlađenja kruha s dodatkom kiselog tijesta poboljšao je njegov oblik i poroznost, smanjio kiseli okus i mrvljivost, te posvijetlio boju kore. Stoga se ovi procesi mogu uspješno primijeniti za poboljšanje skladišne kakvoće polupečenog kruha pakiranog u modificiranoj atmosferi.Driven by the bakery industry urge to satisfy consumer demand for fresh, diverse and high quality bakery products, we investigated the influence of barley sourdough and vacuum cooling on shelf life quality of partially baked bread stored in modified atmosphere packaging at ambient conditions. Barley sourdough was fermented with Lactobacillus reuteri (DSM 20016, F275). Partially baked bread with sourdough was microbiologically acceptable during 30 days of storage, while bread without sourdough had detectable mould on the 30th day. Stored bread samples were rebaked after 1, 8, 15, 22 and 30 days to determine moisture content, physical and sensorial properties. Moisture loss (5 %) was detected on the 15th day, after which it remained stable until the end of investigated storage period. Nevertheless, textural quality of stored bread continuously declined due to crumb firming. Bread flavour did not change during mould-free storage time. The principal component analysis identified major differences in the flavour of sour and control bread, also in crumb firmness and moisture content of samples. This study indicates the positive role of barley sourdough fermented with L. reuteri in improving crumb texture for at least 15 days, and ensuring mould- and bacteria-free partially baked bread for 30 days. Vacuum cooling combined with sourdough improved bread shape, porosity, and reduced sour taste, crust colouring and rumbliness. Hence, it can successfully extend shelf life quality of partially baked bread in modified atmosphere packaging

Brašno - Kruh '15

Proceedings contains 28 original research articles presented at 8th International Congress Flour – Bread ’15 and 10th Croatian Congress of Cereal Technologists Brašno – Kruh ’1

Application of food industry by-products and innovative technologies in development of bakery products for celiac and diabetes patients

Bezglutenski pekarski proizvodi su najčešće male prehrambene vrijednosti, visoke cijene, kratke trajnosti i visokog glikemijskog indeksa. Cilj ove disertacije bio je razvoj bezglutenskog kruha zadovoljavajuće prehrambene vrijednosti i produžene trajnosti, dodatkom heljde, prosa i bučine pogače te primjenom inovativnih tehnologija. Primjena ultrazvuka visokog intenziteta i kriogenog mljevenja značajno povećava dostupnost bioaktivnih spojeva heljde i bučine pogače, a vakuum hlađenje u kombinaciji sa pakiranjem produžuje trajnost bezglutenskog kruha. Proizvedeni bezglutenski kruh je bogat proteinima i izvor vlakana, ima umjereni glikemijski indeks te ima bolju fizikalno-senzorsku kvalitetu od bezglutenskog kruha prisutnog na tržištu te se može preporučiti oboljelima od celijakije i šećerne bolesti.Gluten free products are most often of low nutritive value, high price, short shelf life and have a high glycaemic index. Aim of this diseratation was to develop a gluten free bread with a prolonged shelf life and high nutritive value by enrichment with buckwheat, millet and pumpkin seed cake and treatment with inovative technologies. Application of high intensity ultrasound and cryogenic milling enhances the availability of bioactive compounds from buckwheat and pumpkin seed cake, while vacuum cooling in combination with packaging, prolongs the shelf life of gluten free bread. The produced gluten free bread is rich in protein and a source of fibre, it has a moderate glycemic index and a better physical-sensory quality than the gluten free bread present in the market and can also be recommended to patients suffering form celiac disease and diabetes

Influence of Particle Size and Xylanase Pretreatment of Proso Millet Bran on Physical, Sensory and Nutritive Features of Gluten-Free Bread

Research background. Millet bran is a by-product rich in dietary fibre, micronutrients and bioactive compounds which are often deficient in a gluten-free diet. Previously, cryogenic grinding has been shown to improve the functionality of bran to some extent, although it offered limited benefits for bread making. This study aims to investigate the effects of adding proso millet bran depending on its particle size and xylanase pretreatment on the physicochemical, sensory and nutritional properties of gluten-free pan bread. Experimental approach. Coarse bran (d50=223 μm) was ground to medium size (d50=157 μm) using an ultracentrifugal mill or to superfine particles (d50=8 μm) using a cryomill. Millet bran presoaked in water (for 16 h at 55 °C) with or without the addition of fungal xylanase (10 U/g) replaced 10% of the rice flour in the control bread. Bread specific volume, crumb texture, colour and viscosity were measured instrumentally. Along with proximate composition, the content of soluble and insoluble fibre, total phenolic compounds (TPC) and phenolic acids as well as total and bioaccessible minerals of bread were assessed. Sensory analysis of the bread samples included a descriptive, hedonic and ranking test. Results and conclusions. Dietary fibre content (7.3-8.6 g/100 g) and TPC (42-57 mg/100 g) on dry mass basis of the bread loaves depended on bran particle size and xylanase pretreatment. The effect of xylanase pretreatment was most evident in the loaves with medium bran size in terms of higher content of fibre soluble in ethanol (45%) and free ferulic acid content (5%), improved bread volume (6%), crumb softness (16%) and elasticity (7%), but lower chewiness (15%) and viscosity (20-32%). Bread bitterness and dark colour were increased after adding medium-sized bran but its bitter aftertaste, crust crookedness, crumb hardness and graininess were reduced with xylanase pretreatment. Although bran addition impaired protein digestibility, it enriched the bread with iron (341%), magnesium (74%), copper (56%) and zinc (7.5%). Xylanase pretreatment of the bran resulted in the improved bioaccessibility of zinc and copper of the enriched bread compared to the control and bread without xylanase. Novelty and scientific contribution. Application of xylanase to medium sized bran obtained by ultracentrifugal grinding was more successful than its application to superfine bran obtained by the multistage cryogrinding as it resulted in more soluble fibre in gluten-free bread. Moreover, xylanase was proven beneficial in maintaining desirable bread sensory properties and mineral bioaccessibility