Optimization of low-cost drying methods to minimize lipid peroxidation in Spirulina platensis grown in the Philippines

摘要

Three low-cost drying methods (sun, solar, and draft oven) were optimized to produce Spirulina powder of optimal quality. Optimization in the pre-dehydration stage included the use of two antioxidants, l-tocopherol and tertiary-butyl hydroquinone (TBHQ), and two blanching methods, microwave and water bath, to inactivate enzymes. The efficiency of the pre-dehydration treatments at minimizing lipid peroxidation were evaluated in terms of the product's oxidative stability using the thiobarbituric acid (TBA) test. The sample with the lowest TBA reactive substance (TBARS) value was considered the most stable. TBHQ was found to be significantly better than l-tocopherol in minimizing lipid peroxidation in blanched samples while l-tocopherol was better than TBHQ in unblanched samples. Microwave blanching exerted a greater stabilizing effect than water bath blanching. The combined effect of TBHQ and microwave blanching was found to be the most effective pre-dehydration treatment for minimizing lipid peroxidation in drying Spirulina. Among the three low-cost optimized drying methods, sun-drying produced a dried product with the lowest TBARS value (0.472 mg malondialdehyde.kg-p#), which was closest to that of the spray-dried (control) sample (0.434 mg MDA.kg-p#). Draft oven and solar drying produced dried products with the same average TBARS value (0.56 mg MDA.kg-p#). Sun-drying, when optimized, produced a dried product that was almost as stable as the spray-dried product.