Study of Betalains Compound, Sugars, and Moisture Content on Pablo Beetroot Root Size from the UK and Spain

<p dir="ltr"><b>Background</b>: Beetroot is a vital root vegetable with health-promoting benefits. However, the sugar composition, moisture content, and betalains compound in relation to root sizes have yet to be fully understood. </p><p dir="ltr"><b>Main Aim</b>: This study aims to investigate the influence of root size compositions (with an emphasis on moisture content (MC), betalains, and sugar content (SC)) of Pablo beetroot (PB) sourced from the United Kingdom (UK) and Spain. </p><p dir="ltr"><b>Materials and Methods</b>: MC was determined using convective fan oven drying (FOD), vacuum oven drying (VOD), halogen moisture analyser (HMA), and a volumetric Karl Fischer titration (VKFT) method. The samples were dried in the FOD at 103°C, VOD at 70°C, 100 mmHg for 1- 24 h, and HMA at 50-160°C for 2.0-27.6 mins. VKFT moisture content was determined using solid beetroot and methanolic extracts. Betalains were determined spectrophotometrically. Blending extraction techniques and treatments such as solvents, pH, ascorbic acids, ultrasonicated water, storage temperatures, different beetroot sizes, and parts were investigated to determine the yield and concentration of betalains. The impact of root sizes and oven drying temperatures (50, 70, and 103°C) on beetroot sugar content was measured by high-performance liquid chromatography and a refractive index detector (HPLC-RID) and compared with total soluble solids by refractometer. </p><p dir="ltr"><b>Main Finding</b><b>s</b>: The results of the MC of retail PB UK determined by FOD ranged between 84.6 and 86.5% wwb, VOD ranged between 82.4 and 85.5% wwb, and HMA ranged between 1.54- 85.14% wwb. VKFT has a MC of 85.7% wwb. The MC of retail PB Spain and supplier PB UK was significantly higher (P<0.05) in larger root sizes than the medium and smaller root sizes using FOD and VOD methods. However, there was a significantly (P<0.05) lower MC in all the root sizes of the PB sourced from the supplier PB UK and retail PB Spain, determined by the VKFT method on methanolic extracts. For the betalains extraction (BE), the peel part extraction with deionised water has an optimum yield and concentration of betalains with a value ranging from (1,717 to 2,453 mg /100 g DW) compared with other extraction media. The large root size of retail PB UK had more betalains content than retail PB Spain and supplier UK. There was a correlation between sucrose content and total soluble solids. The large root sizes of retail PB (UK) had higher SC in fresh samples (58.30 g/100 g DW) than the small and medium sizes, as well as retail PB Spain and supplier PB UK. However, oven drying at 103°C significantly reduced glucose, fructose, and sucrose content in supplier PB UK. Surprisingly, oven drying at 50 and 70°C increased the sucrose level in retail PB Spain and retail PB UK.</p><p dir="ltr"><b>Conclusions</b>: The study shows that the root sizes of PB sourced from the UK and Spain were observed to have variations in the MC, BE, and SC. Therefore, root sizes are a crucial factor in beetroot composition. This suggests there is scope to investigate the impact of beetroot size on other beetroot bioactive compounds.</p>