Physico-chemical properties and sensory acceptance of mixed drinks of red cabbage (Brassica oleracea L.) and roselle (Hibiscus sabdariffa L.) extracts

The present work aimed to determine the best formulation of mixed drink made from red cabbage and roselle extracts. Six mixed drink formulations were prepared based on different ratios of red cabbage to roselle extracts: F1 (30:20); F2 (35:15), F3 (40:10); F4 (20:30); F5 (15:35) and F6 (25:25). Samples were prepared by pasteurising the mixed drinks with the pre-determined amount of ingredients at 90°C for 5 sec. The pH of roselle extract (2.06 ± 0.02) was found to be more acidic as compared to red cabbage extract (6.38 ± 0.03). This contributed to the low pH in mixed drink formulations (2.68-3.48). Total titratable acidity (TTA) (0.44-0.89% malic acid w/v) and total anthocyanin content (247.99-339.77 mg cyanidin-3-glucoside/L) were shown to increase significantly with increasing roselle extract concentration. Similarly, total soluble solids (TSS) (12.23-12.83°brix) was found to increase significantly with higher ratio of red cabbage extract due to high TSS content (7.67 ± 0.08°brix) in the extract as compared to roselle extract (4.63 ± 0.09°brix). There were significant differences among all the samples in L*, a* and b* values. Mixed drink formulations that contained higher concentration of red cabbage extract were lighter and redder in colour. Significant differences were observed in sweetness, sourness, taste and overall acceptability of drinks, with F3 yielding the highest mean scores for all attributes. Mean score of sensory attributes of the mixed drinks were related to physicochemical properties. Mean scores of all sensory attributes had negative correlation with TTA. Sweetness mean score was positively correlated to the L* value, sourness mean score was positively correlated with pH, L* and a* values but negatively correlated with b* value, and colour mean score had positive correlation with a* value. Therefore, it can be concluded that panellists preferred less sour drinks, which were lighter and redder in colour.β-carotene onto the PKSAC in a model system but yielded the highest desorption efficiency.