Physical properties of microencapsulated anthocyanin obtained by spray drying of Red Amaranthus extract with maltodextrin

ABSTRACT

Introduction: Anthocyanins are water-soluble plant pigments responsible for bright red, purple and blue colours in fruits and vegetables. Extraction of anthocyanins from plant cells becomes an important task closely related to the need of preservation of their bioactivity. Therefore, encapsulation by spray drying is a technique used to retain maximum anthocyanin and colour. Methods: The study was designed to investigate the physical properties of spray drying of Red Amaranthus extract with maltodextrin. The extract was prepared by soaking washed and finely chopped red spinach (Red Amaranthus) leaves in water for 72 h at 4°C of with potable water (solvent), followed by storage at refrigerated condition at 4°C for 72 h. The extract was mixed with maltodextrin solution in three different ratios: 1:1, 1:2 and 1:3. Powder properties were studied for the three different extract and maltodextrin ratios that were fed in the spray dryer. All analyses were conducted in triplicates. Results: The 1:1 ratio retains maximum anthocyanin 93.03 mg/100g of spray dried powder compared to the other ratios; the moisture content of the 1:1 ratio was 0.44% (dry basis). The color chroma value of a* of 1:1 ratio was 26.24 and density was 0.55 g/cm3 whereas the water activity of the sample was 0.62±0.01. By comparing the three ratios, the 1:1 ratio of extract and maltodextrin was the optimum combination for encapsulation of anthocyanin using spray-drying technique. Conclusion: Encapsulation with maltodextrin at 1:1 ratio had a significant impact on retention of anthocyanin and colour in the final produ