Philippine E-Journals

Quality of spray-dried and oven-dried roselle (Hibiscus sabdariffa L.) powders

Imma Concepcion Estabillo

Discipline: agriculture, food and related studies

 

Abstract:

Roselle (Hibiscus sabdariffa L.) contains significant amount of anthocyanins and Vitamin C, however, these nutrients are heat sensitive and are easily degraded during heat processing. This study assessed the influence of drying methods on the physicochemical properties of roselle powders. The 80:20(extract:maltodextrin) liquid feed formulation produced the best quality spray-dried powder. Optimum parameters for spray-drying was established at inlet temperature, Ti = 173+ 1°C, outlet temperature, T0 = 73 +1°C, feed rate(R) of 10 rpm and air pressure (P) of 1.5 – 2.0 bars. Presoaking conditions anddrying methods significantly influenced the antioxidant components of the roselle extract powder. At higher water temperatures (50C° and 100°C), higher losses of anthocyanin and Vitamin C were recorded. Likewise, similar changes were observed in the oven – dried (45°C, 24h) roselle powder. Spray – dried powder had lower Aw, moisture, protein, ash and fiber contents than the oven –dried powder. This study suggested that spray –drying protects the essential nutrients anthocyanin and Vitamin C, however, degrades the proximate composition of roselle powder.