Characterisation of wholegrain composite for pretzels: a comprehensive nutritional and functional analysis

Abstract

Wholegrain composite flours are used for bakery products to enhance their nutritional value and to decrease the reliance on wheat importation as well as to ensure food security in most developing countries. This work aimed to optimise oat, maize, barley and wheat flour levels in the development of nutritionally enriched wholegrain pretzels. Composite flour blends were prepared by mechanical mixing of oat flour (OF), barley flour (BF), maize flour (MF) and wheat flour (WF) in the following proportion: WF (100%) (T0 – control), W:B (90:10) (T1), W:M (90:10) (T2), W:O (90:10) (T3), W:B:M:O (85:5:5:5) (T4), W:B:M:O (76:8:8:8) (T5) and W:B:M:O (70:10:10:10) (T6). Wholegrain composite flour mixes were analysed for their proximate composition and antioxidant properties. The fat, protein, ash and moisture content significantly changed (P < 0.05) in all treatments, while the fibre content increased. DPPH radical scavenging activity and total phenolic and flavonoid content showed significant changes compared to the control. A rapid visco analyser determined multigrain flour's rheological and pasting properties, and the values showed significant (P < 0.05) differences for peak viscosity, final viscosity and pasting temperature. The final product was analysed for proximate analysis, texture, colour and sensory evaluation. The increase in moisture, protein, fibre and ash content of the product was observed. Moisture, fat and fibre content of pretzels exhibited significant correlations (P < 0.05) with the sensory parameters. A grouping of the samples in function of the chemical and sensory characteristics was depicted from the principal component analysis. Texture and colour analysis showed significant differences (P < 0.05). Sensory evaluation results showed that the overall score for acceptability found for composite flour mix which contains 10% barley, 10% oat and 10% maize with wheat in a 30:70 ratio was accepted by the consumer. Consumption of wholegrain pretzels as snack food can contribute to a nutritious and balanced diet.