Nutritional quality of grain sorghum (Sorghum bicolor L. Moench) and the potential of its application in the food industry

[S. Jaćimović]

105 str.

Biotehničke nauke -Tehnologija ratarskih proizvoda / Biotechnical sciences- Technology of agricultural products

Uzimajući u obzir globalni trend zdravog načina života, koji podrazumeva povećanu potrošnju prirodnih proizvoda, neophodno je konstantno uvođenje novih sirovina za proizvodnju visokokvalitetne hrane. Zbog sve češće pojave zdravstvenih problema povezanih sa intolerancijom na gluten, raste interesovanje za žitima koja ne sadrže gluten. Ujedno, veliki izazov za prehrambenu industriju predstavlja unapređenje bezglutenskih proizvoda i proizvoda sa smanjenim sadržajem glutena, pa je broj studija na ovu temu u neprestanom porastu. Jedan od načina da se poveća upotreba sirka i svest o značajnosti uvođenja ovog bezglutenskog žita u ishranu ljudi je detaljno ispitivanje nutritivnog kvaliteta i kreiranje novih prehrambenih proizvoda. Prvi cilj istraživanja u okviru ove doktorske disertacije bio je biohemijska karakterizacija jedinjenja primarnog i sekundarnog metabolizma semena 172 genotipa sirka (Sorghum bicolor L. Moench) i analiza nutritivnog kvaliteta semena radi odabira superiornih genotipova za primenu u proizvodnji visokokvalitetnih prehrambenih proizvoda. Karakterizacija glavnih parametara nutritivnog kvaliteta, koji karakterišu biološku vrednost zrna sirka, sprovedena je standardnim procedurama analize. Rezultati ispitivanja i dobijene vrednosti su upoređene sa međunarodno priznatim standardnim vrednostima (CXS 172-1989, CERSOR010, 2020) u cilju izdvajanja i dalje analize genotipova pogodnih za ishranu ljudi. Na ovaj način, izdvojeno je šesnaest genotipova u kojima je utvrđen polifenolni, aminokiselinski i masnokiselinski sastav, sadržaj makro- i mikro- elemenata i antioksidativna aktivnost. Takođe, izvršena je teorijska procena nutritivne vrednosti radi utvrđivanja potencijala ovih genotipova kao izvora makro- i mikro- elemenata kroz ishranu. Istraživanja su pokazala da je seme sirka dobar izvor makro- i mikro- elemenata koji su od vitalnog značaja za pravilan rad metabolizma, dok ga prisutne bioaktivne komponente čine jednim od perspektivnih sirovina za proizvodnju hrane sa dodatom vrednošću. Broj dostupnih bezglutenskih proizvoda sa poboljšanim svojstvima na tržištu je mali, što ostavlja prostora za uvođenje novih sirovina i kreiranje novih proizvoda. Tako, poslednju celinu ove disertacije predstavljala je priprema bezglutenskog čajnog peciva. Premium bezglutenska smeša predstavljala je osnovu kreiranog proizvoda, dok je bezglutensko brašno sirka korišćeno kao funkcionalni dodatak u nivou supstitucije 20% i 40%. Valorizacija potencijala brašna sirka kao sastojka u proizvodnji bezglutenskih proizvoda izvršena je kroz analizu senzornog profila, utvrđivanjem uticaja dodatka brašna sirka na senzorne karakteristike bezglutenskog čajnog peciva. Na osnovu analize podataka dobijenih senzornom ocenom, dodatak integralnog brašna sirka poboljšava teksturna i aromatska svojstva kontrolnog proizvoda. Uzorci koji sadrže integralno brašno sirka pokazali su izbalansirane karakteristike u pogledu vizuelnog kvaliteta, teksture i arome što naglašava potencijal primene sirka kao vredne sirovine za prehrambenu industriju.

Considering the widespread trend towards a healthy lifestyle, which implies increased consumption of natural products, it is necessary to introduce new raw materials to produce high-quality food constantly. Due to the increasing occurrence of health issues related to gluten intolerance, there is a growing interest in cereals that do not contain gluten. At the same time, a big challenge for the food industry is the improvement of gluten-free products and products with reduced gluten content, which is why there are a rising number of studies on this subject. One way to increase the use of sorghum and awareness of the importance of introducing this gluten-free grain into the human diet is to examine its nutritional quality and create new food products thoroughly. The first goal of the research within this doctoral dissertation was the biochemical characterization of compounds of primary and secondary metabolism of 172 sorghum genotypes (Sorghum bicolor L. Moench) as well as the comparison of seed nutritional quality parameters, intending to select the most potent genotypes for use in the production of high-quality food products. The main nutritional quality parameters, which characterize the biological value of sorghum grains, were characterized using standard analysis procedures. The test results and obtained values were compared with internationally recognized standard values (CXS 172-1989, CERSOR010, 2020) in order to isolate and further analyze genotypes suitable for human consumption. In this way, sixteen genotypes were isolated in which the polyphenolic, amino acid, and fatty acid composition, the content of macro- and microelements, and antioxidant activity were determined. Also, a theoretical evaluation of the nutritional value was carried out to determine the potential of these genotypes as a source of macro- and microelements through nutrition. Research has shown that sorghum seeds are a good source of macro- and micro-elements that are vital for the proper functioning of metabolism, while the bioactive components present make it one of the promising raw materials for food production with added value. The number of gluten-free products with improved properties available on the market is small, which leaves space for the introduction of new raw materials and the creation of new products. Thus, the last part of this dissertation was the preparation of gluten-free tea pastry. The premium gluten-free mixture was the basis of the created product, while the gluten-free sorghum bran was used as a functional supplement at the substitution level of 20% and 40%. Valorization of the potential of sorghum flour as an ingredient in the production of gluten-free products was carried out through the analysis of the sensory profile, by determining the influence of the addition of sorghum flour on the sensory characteristics of the tea pastry. Based on the analysis of the data obtained by sensory evaluation, the addition of integral sorghum flour improves the textural and aromatic properties of the control product. Samples containing whole sorghum flour showed balanced characteristics in terms of visual quality, texture, and aroma, emphasizing sorghum application's potential as a valuable raw material for the food industry.

Sorghum bicolor L. Moench, nutritivni kvalitet, prehrambena industrija, bezglutensko čajno pecivo, senzorna analiza

sorghum, Sorghum bicolor L. Moench, nutritional quality, food industry, gluten-free biscuits, sensory evaluation

664.64:633.17(043.3)

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