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Abstract
Banana puree is a complex mixture of proteins, carbohydrates and phenolics. The addition of whey protein to produce fortified banana beverages may be a better way to utilize wasted bananas in banana producing countries where malnutrition prevails. This work characterized the components of the banana pulp and their chemical interactions and selected sensory and physical measurements to get a better understanding of the formulated whey-banana beverages. High methoxyl pectin (DE > 80) and low molecular weight proteins were present in banana, mango and orange pulps. Aspartic acid in protein pulps was predominant while methionine and tyrosine contents were very low. Phenolic compounds were highest in banana pulp (138 2 mg gallic acid equivalent/L = mg GA/L) compared to 102 8 mg GA/L for orange. Phenolic compounds were about 10 fold less (15 2 mg GA/L) in mango. The interaction between whey proteins (10%, w/w) and pectin (0.4%, w/w) was evaluated in acidified banana beverage model systems using rheology and particle size measurements. Pectin-protein interaction influenced the mechanical properties whereas sucrose influenced the particle size of the whey-banana beverage. Except for the first week, the particle size was constant for 60-day storage at 4, 20, 30 and 40 o C. While the products remained light colored (L* ~ 71) for 60 days, redness (a*),yellowness (b*) and saturation (c*) increased at elevated temperatures. The hue angle (H*) was less at elevated temperatures however. The product was a sour, sweet, smooth beverage with distinctive banana flavor and minimum off-flavor. Sourness and acidity were critical quality factors for consumer acceptability. Sedimentation was maximum at 40C while serum separation was minimum at 4C. Sedimentation was greater for non-UHT than UHT treated whey-banana beverages and increased with increased storage temperature for 17 days of storage. The flow behavior and consistency indexes were comparable for both UHT and non-UHT treated samples. The flow behavior decreased with increasing temperature as the consistency increased. The particle size measurements (D43, D32) were greater for the non-UHT product and were independent of time and temperature. Higher color values were observed for the UHT beverage.