title: Investigation of beta-glucan extracts from barley grain as ingredient in food formulations
Creators: name: Alsalem, Dana Khaled
Publisher: name: University of Reading
Year: 2024

description: Barley has been cultivated since antiquity and is the richest source of beta-glucans among 
all other cereals. Consumption of beta-glucans has been associated with positive health effects in 
humans. Specifically, the Federal Drug Administration (FDA) supports the claim that beta-glucans 
can reduce serum cholesterol and insulin levels and recommends consumption of three grams of 
beta-glucans per day for health benefits. Although barley is widely available, barley grain 
consumption is currently quite low, as rice and wheat are more popular types of cereals. The 
overarching purpose of this research project was to identify alternative ways for the utilisation of 
barley in the food industry and explore the technological properties of barley beta-glucans as a 
functional food ingredient. To this end, the main goal of the present study was to develop an 
efficient extraction process for beta-glucans from barley grains grown under different 
environmental conditions (Jordan and the UK) and incorporate these extracts into a food product 
to investigate the main physicochemical properties they impart in the food matrix. The 
experimental work of this thesis included the investigation of two extraction methods targeting 
beta-glucan extraction from barley flour. The first was conventional hot water extraction (HWE)
method, in which different extraction times (90 min, 3 h and 4 h) and temperatures (50°C, 60°C 
and 70°C) were tested on defatted UK and Jordanian barley flour. The highest beta-glucan 
recoveries for the UK (9.3%, w/w) and the Jordanian barley (10.5%, w/w), respectively, were 
achieved at 60°C for 4 h and 50°C for 3h, respectively. Due to the low recovery yields of HWE, 
another method was investigated, that of ultrasound assisted extraction (UAE). Optimisation of 
the UAE conditions was followed by characterisation of the physicochemical and functional 
properties of the extracts. At the optimum extraction conditions for each barley cultivar, the highest 
beta-glucan recovery of 73.2% (w/w) was obtained for the Jordanian barley at a UAE amplitude of 15 for 35 min, which provided extracts with beta-glucan purity of 12.9% (w/w). For the UK 
barley, 10 A ultrasonication for 20 min resulted in beta-glucan recovery of 55.5 % (w/w),
containing 10% (w/w) beta-glucans. The extracts contained also low amounts of protein (less than 
0.35%, w/w) but considerable amounts of starch (53.3% for Jordanian 22.4% for UK barley, 
respectively). Subsequently, the effect of barley flour substitution levels, as well as the addition of 
UAE extracts in cracker formulations was investigated. Six cracker formulations were prepared 
with barley flour inclusions of 10–60% (w/w). Two wheat cracker formulations enriched with 
beta-glucan extracts obtained via UAE were also developed. The resulting products were evaluated 
for their beta-glucan content, colour (L*, a* and b*), texture (hardness and crispness), water 
activity, moisture content, and dough penetration. Crackers produced with various proportions of 
barley flour demonstrated, as predicted, higher beta-glucan content than wheat crackers (control), 
ranging from 0.377 g/100 g for 10% UK barley flour to 1.542 g/100 g for 60% Jordanian barley. 
Wheat crackers with beta-glucan extracts demonstrated the highest beta-glucan content of 2.436 
g/100 g and 2.673 g/100 g using the UK and Jordanian barley extracts, respectively. Barley flour 
cracker formulations exhibited darker colour, had greater redness values, were harder and less 
crispy than control wheat crackers. When comparing the replacement 60% wheat flour by barley 
flour with the addition of beta-glucan extract, a significant improvement in water activity and 
textural properties of the final product was observed. Moreover, UAE beta-glucan extracts were 
considered suitable to produce crackers with a high beta-glucan content that could meet the US 
FDA requirement.