PRESERVING PINEAPPLE JUICE NATURALLY: IMPACTS ON SHELF LIFE AND NUTRIENTS OF SELECTED GHANAIAN PINEAPPLE (ANNAS COMOSUS) JUICES

Abstract: Pineapple (Ananas comosus) is a widely consumed tropical fruit, but its high
perishability limits its shelf life. This study assessed the juice yield and the effects of natural
preservatives (rosemary and clove) on the quality of three pineapple varieties (Smooth Cayenne,
Sugarloaf, and MD2). A 3 × 3 Factorial Completely Randomized Design was used, with variety
and preservative as factors, each at three levels. Smooth Cayenne had the highest juice yield
(700 mL). Sugarloaf juice preserved with rosemary had the highest crude fiber, fat,
carbohydrate, protein, and ash, while the unpreserved Sugarloaf variety had the highest crude
moisture content. On day ten, the highest pH (5.43) was recorded in juice from the MD2 variety
with no preservative, while the lowest pH (5.15) was observed in MD2 juice preserved with
rosemary. The highest Total Soluble Solids (TSS) value (14.01 °Brix) was found in MD2 juice
treated with clove, while the lowest TSS (0.91 °Brix) was observed in Sugarloaf and Smooth
Cayenne juices preserved with rosemary. The Smooth Cayenne variety with rosemary exhibited
the highest Total Titratable Acidity (TTA) on day one (0.00078), and still had the highest on day
ten (0.00077) without preservatives, while the lowest TTA values (0.00043 and 0.00042) were
recorded in Sugarloaf juice preserved with clove on days one and ten respectively. Vitamin C
content was highest in Smooth Cayenne juice with no preservative (25.24 mg/100 mL on day
one and 21.72 mg/100 mL on day ten), while the lowest vitamin C levels were found in MD2
juice 5.28 mg/100 mL both with no preservative (day one) and with rosemary-clove mix (day
ten). Mineral analysis revealed no statistically significant differences in copper, potassium,
phosphorus, and zinc content for both juices tested as day one samples, however a statistical
difference was observed on day ten among all four minerals due to the effects of preservatives.
Specifically, the highest concentration of copper (5.48 mg/L), was found in MD2 samples
preserved with clove, whereas the lowest (3.20 mg/L) was identified as MD2 samples preserved
with no preservative. In addition, iron concentrations were highest at 31.28 mg/L in Sugarloaf
samples preserved with rosemary, while the lowest (9.49 mg/L) was determined in MD2 samples
preserved with no preservative. Manganese concentrations were greatest (14.83 mg/100 mL) in
MD2 samples preserved with no preservative. The highest levels of potassium were observed in
Smooth Cayenne samples preserved with clove. Phosphorus was found to be at its highest level
in MD2 samples preserved with clove. Finally, zinc was also found to be highest in MD2
samples preserved with clove and lowest in Sugarloaf samples preserved with clove. Sensory
evaluation of the samples demonstrated that neither rosemary nor clove resulted in an
unacceptable deterioration of the sensory attributes of the juice or nutritional degradation.
Therefore this study demonstrates the feasibility of using natural preservatives to extend the
shelf-life of pineapple juice while maintaining its quality.