Optimization of mature coconut water with calamansi, stevia, and turmeric using mixture design

Abstract

In the Philippines, the Zero Food Waste Act of 2022 has been proposed with the aim of implementing a system that promotes food waste reduction through redistribution, recycling, and valorization. One of the wastes produced from the coconut industry is the mature coconut water, as the primary focus is on the production of copra, coconut oil, and coconut milk. Further, mature coconut water has poor sensory properties (color/turbidity, aroma, and taste), leading to approximately 2.4 billion liters being discarded annually. One of the proposed solutions is to utilize the D-optimal mixture design, which enables the generation of the best combination of mature coconut water (83.5–91.3 g/100 g), calamansi (8.00–15.00 g/100 g), stevia (0.50–1.50 g/100 g), and turmeric powder (0.20 g). The 'desirability' function was employed to achieve multiresponse optimization, considering parameters such as pH < 4.5; sweetness, sourness, and overall acceptability all equivalent to 6 (like slightly). Significant (p < 0.05) responses indicated that the influence of the raw materials varied, ranging from linear to cubic prediction models, with R2 values ranging from 70.19 to 98.30%. The optimization results revealed that the model successfully predicted the properties of the optimal formulation composed of 90.08 g/100 g mature coconut water, 8.83 g/100 g calamansi, 0.90 g/100 g stevia, and 0.20 g/100 g turmeric powder. The results of this research may help industries valorize mature coconut water instead of discarding it as waste. The developed beverage may be further improved to increase its acceptability and generalizability by increasing the range of the values used and verify results through pilot-scale production.