Abstract:
The need for beverages to perform dual role of quenching thirst and modulate diseases under
suitable storage conditions was the background for this study. Storage changes of antioxidants in
previously developed beverage formulations from pineapple, Hibiscus sabdarriffa extract,
oranges and carrots (40, 26.3, 17.2 and 16.5%), respectively was investigated. The blend was
filled into bottles and part of it pasteurized at 90 o C for 5 min and the other part left
unpasteurized. The pasteurized and unpasteurized samples were stored at room and refrigeration
temperature for 4 months. The effect of storage time, pasteurization and storage conditions on
proximate composition, microbial loads, physicochemical properties (Total titratable acidity
(TTA), Total sugar, total solids and pH), sensory properties, colour and antioxidants activities
[(1,1-diphenyl–2 picrylhydrazyl (DPPH) radical scavenging ability, 2, 2’-azino-bis (3-
ethylbenzothiazoline-6-sulphonic acid) ABTS, Vitamin C, Total phenols, Ferric Reducing
Antioxidant Potential (FRAP), Total carotenoids] were determined. The values for TTA, pH,
total sugar, vitamin C, carotenoid, phenol, FRAP, DPPH, ABTS and Flavonoid ranged from
0.61%-4.50%, 1.92-4.95, 5.20-7.85 o brix, 15.24-26.13mg/100g, 0.34-4.59mg/100g, 8.89-
23.57mg/ml, 108.40-685.99mg/ml, 44.19-86.94%, 0.02-0.03mM/g and 0.08-0.19 respectively
for all samples. The total titratable acidity and microbial loads increased with increase in storage period. Fresh unpasteurized beverage sample was associated with high antioxidant activities,
vitamin C and carotenoid compared with the fresh pasteurized sample. Antioxidant activities in
all the beverage samples decreased significantly (p˂0.05) after 4 months of storage, however,
refrigerated storage temperature maintained higher antioxidants activities. Combination of
pasteurization and storage at refrigeration temperature retained 75% vitamin C, 53% carotenoid
and 56-79% antioxidants activities, respectively. Lastly, the study confirmed that the degradation
of vitamin C content in the beverages followed the first order reaction.
