Colour characteristics, phenolic content and antioxidant activity of Spirulina platensis soaked in basil (Ocimum basilicum) leaves extract

Spirulina platensis has been known as a super food with a high nutrition and biological activity. The limited addition of S. platensis into the food is due to its unpleasant odour. S. platensis was soaked in basil (Ocimum basilicum) leaves extract (BLE) to decrease the unpleasant odour and its antioxidant activities after soaking were unknown. This study aimed to evaluate the effect of ratio S. platensis with BLE on colour and sensory characteristics and to determine the total phenolic content (TPC) and antioxidant capacity of extracted S. platensis without and with BLE using different solvents. Spirulina platensis was soaked in BLE at a ratio of S. platensis and BLE of 1:3, 1:4, and 1:5 (w/v) for 15 min and then dried at 40 degrees C for 10 h. The resultant powder was analysed for colour and sensory characteristics. The selected S. platensis with the best sensory characteristic was further extracted in water and ethanol and was compared with the S. platensis control (unsoaked in BLE). The ratio of S. platensis and BLE had a significant effect on the colour characteristics (P < 0.05). Spirulina platensis soaked in BLE at a ratio 1:4 had higher L* (35.98), a* (-6.57) and b* values (5.95) than the control. The ratio of S. platensis and BLE at 1:4 had a higher overall sensory value (4.16) than the control (2.35). The water extract of S. platensis unsoaked and soaked in BLE showed a higher TPC (1.178 and 1.667 mg GAE g(-1) extract, respectively), DPPH, ABTS and metal chelating, but lower in FRAP compared with the ethanol extract. Spirulina platensis soaked in BLE which were extracted in water and ethanol had higher ORAC (63.27 and 56.33 mmol Teq g(-1) extract, respectively) than the control. Spirulina platensis soaked in BLE increased its sensory value while maintaining the antioxidant capacity. Therefore, it can potentially be added in more quantities to various foods as functional foods.