Nutritional evaluation of protein concentrates isolated from two red seaweeds: Hypnea charoides and Hypnea japonica in growing rats

The nutritional values of protein concentrates (PCs) isolated from two subtropical red seaweeds, Hypnea charoides Lamouroux and H. Japonica Tanaka, were evaluated in growing rats. The protein quality of the two seaweed PCs was determined by comparing the net protein ratio (NPR), true protein digestibility (TD), nitrogen balance (NB), biological value (BV), net protein utilization (NPU) and utilizable protein (UP) of the two seaweed PCs diet groups with those of the casein control group. There were no significant differences of NPR and BV in all diet groups. Although the values of TD (ranged from 90.5 to 90.6%), NB (ranged from 108 to 113 mg rat1 day1), NPU (ranged from 80.1 to 81.3%) and UP (ranged from 80.1 to 81.3%) of these two PCs were significantly lower than those of the casein control, they were comparable to those of other common plant PCs. The growth performance of rats fed the two PCs diets was satisfactory and both PCs had no adverse effect on the weight of their major organs. Together with their good protein quality as mentioned above, the PCs from the two red seaweeds under study could be a potential alternative protein source for human nutrition.