In-Vitro Study on Fermentation Characteristics of Different Hulless Barley Cultivar Flakes

Abstract

Barley (Hordium vulgare L.) grain is an important food ingredient due to the presence of essential compounds like β-glucans, proteins, resistant starch, phenolic compounds etc. β-glucans are able to lower cholesterol level in blood plasma and the glycaemic index, to enhance lipid metabolism and to reduce the risk of colon cancer. Hulless barley cultivars are more suitable to the human diet, because the hulls can be easily removed, as well as minimal grain processing in food production contributes to the full benefit of the whole grain. Several studies show that hulless grains have a higher digestible energy, and they have higher protein content compared to hulled grains. Different cultivars have unique composition and physical properties. The hulless barley cultivars are less studied than hulled barley and oats. The aim of this study was to evaluate the fermentation characteristics of flakes of different hulless barley cultivars in vitro and to analyse the fermentation pattern of β-glucans and proteins. Samples of six hulless barley cultivar flakes with different β-glucan (4.17–6.59%), soluble dietary fibre (18.1–32.0%) and resistant starch (0.74–10.65%) content were boiled in water 10 min, and the obtained porridge samples were treated under in vitro fementation conditions. The concentration of fermented porridge solids as well as β-glucans and proteins was measured. The concentration of undigested solids varied from 38.3 to 61.0% depending on barley cultivar. The concentration of protein was not significantly changed, but β-glucan concentration was significantly decreased after in vitro digestion comparing to indigestible samples.

Kailgraudu mieži ierauga fermentācijā = Hull-less barley in sourdough fermentation

“…Kailgraudu miežu šķirne Kornelija potenciāli spēj nodrošināt augtāku proteīna saturu nekā citas kailgraudu miežu šķirnes, ierindojot to starp augsta olbaltumvielu (>15%) satura šķirnēm (Auziņš et al, 2021). Kailgraudu miežu pētījumā šķirnes Kornelija miltos konstatēts otrs augstākais olbaltumvielu saturs 18.19 g 100 g −1 līdzās šķirnei Pihl (Norvēģija) (Majore et al, 2021). Kailgraudu miežu šķirnes Kornelija miltu augsto olbaltumvielu saturu konstatējuši arī citi pētnieki un noteikuši no 7 dažādām valstīm saņemtu 35 miežu šķirņu starpā Kornelija miltos būtiski augstāku olbaltumvielu saturu 18.3 g 100 g -1 atšķirībā no citiem miežu miltu paraugiem (Xhaferaj et al, 2023).…”

“…Cietes saturs kailgraudu miežu miltos noteikts 51.88  0.22 g 100 g −1 , un tas nav vērtējams kā ļoti augsts. Majore et al (2021) pētījums parāda, ka cietes saturs dažādas izcelsmes kailgraudu miežu šķirnēs variē 49.15 − 64.06 g 100 g −1 . Kornelija šķirnes miltos noteikts 0.88  0.30 g 100 g −1 rezistentās cietes, kas nav augsts starp dažādām šķirnēm un neliecina par augstu amilozes saturu cietē.…”