Nutritivna i fizikalna svojstva bezglutenskoga kruha s dodatkom posija prosa

master's thesis

• Title (english): Nutritive and physical characteristics of gluten-free bread with millet bran
• Author: Lucija Štrkalj
• Mentor: Dubravka Novotni (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Cereal Chemistry and Technology); Zagreb
• Defense date and country: 2019-09-23, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Nutrition

Abstract

Bezglutenski kruh često ima neadekvatan nutritivni sastav i nepoželjne senzorske karakteristike pa se traže načini za njegovo obogaćivanje. Proso je nedovoljno iskorištena bezglutenska žitarica čije su posije bogate vlaknima, fenolnim spojevima i mikronutrijentima. Stoga je cilj ovog rada bio ispitati mogućnost primjene posija prosa u bezglutenski rižin kruh. Ispitan je utjecaj veličine čestica posija prosa (krupne, srednje i sitne) i utjecaj dodatka enzima ksilanaze na nutritivna i fizikalna svojstva kruha. Analizama je ustanovljeno da je dodatkom posija prosa (10% na brašno) značajno povećan udio vlakana (za 63 – 87 %) i fenolnih spojeva (za 40 – 100 %). Obogaćene vrste kruha mogu se deklarirati kao „izvor vlakana“. Pritom, volumen, tekstura i izgled kruha nisu bili narušeni. Primjenom posija smanjena je viskoznost, što može ukazati na niži glikemijski indeks te produljenu svježinu kruha. Najizraženije djelovanje ksilanaze je primjećeno na kruhu s posijama srednje veličine (d(0,5)=157,03 μm). Navedeni kruh imao je najviši udio vlakana (4,75 g na 100 g kruha) s udjelom topljivih vlakana od 25 %, a udio fenolnih spojeva bio je 27,06 mg na 100 g kruha. Zaključno, primjena posija prosa nutritivno je obogatila bezglutenski rižin kruh, a za optimiranje primjene ksilanaze potrebno je još istraživanja.

Abstract (english)

Gluten-free bread often has poor nutritional composition and sensory characteristics, therefore different methods for its improvement are being developed. Millet is underutilized cereal whose bran is rich in fibre, phenolic compounds and micronutrients. The aim of this work was to examine the addition of millet bran in gluten-free rice bred. The impact of applied 3 different fractions of bran (large, medium and small) as well as the impact of xylanase on nutritive and physical characteristics was observed. Analysis showed that added brans (10 %) significantly increased the amount of fibre (by 63 – 87 %) and phenolic content (by 40 – 100 %). Enriched breads can be declared as „source of fibre“. Volume, colour, texture and appearance were adequate. Said breads also had lower viscosity values, which can be mean lower glycaemic index and longer shelf-life. Xylanase had the biggest impact on bread with medium-size brans (d(0,5)=157,03 μm). It had the highest content of fibre (4,75 g in 100 g bread) with 25 % soluble fibre, and the amount of phenolic compounds was 27,06 mg in 100 g bread. In conclusion, the application of millet bran improved nutritional composition of gluten-free rice bread, and the use of xylanase should be further optimised.

• Keywords: bezglutenski kruh; fenolni spojevi; ksilanaza; posije prosa; prehrambena vlakna
• Keywords (english): dietary fibre; gluten-free bread; millet bran; phenolic compunds; xylanase
• Language: croatian
• URN:NBN: urn:nbn:hr:159:570718
• Study programme: Title: Nutrition; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra nutricionizma (magistar/magistra nutricionizma)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-02-13 12:22:03