In this work valorization of the underexploited industrial solid residue generated after agar extraction from Gelidium sesquipedale was studied by using subcritical water in a semicontinuous fix-bed reactor. First, a complete characterization of this by-product was carried out, determining up to 21% (w/w) of protein content (for a nitrogen factor of 4.9) with high content of essential amino acids, 37% (w/w) of carbohydrate fraction and high amount of ash, 22% (w/w). The effect of temperature, in the range from 129 to 200 °C, and flow rate, in the range from 2 to 6 mL min⁻¹, on protein and carbon fraction extraction/hydrolysis was studied. At constant flow rate of 2 mL min⁻¹, a maximum in the protein extraction was achieved at 185 °C. Higher temperatures led to degradation of protein or its hydrolysis products. Free amino acids release followed the same trend as the protein fraction. The most temperature sensitive amino acids, as determined by gas chromatography (EZ:faast Phenomenex), were serine and aspartic and glutamic acids. As a consequence, the selectivity towards non-polar amino acids increased by working at high severity factors. A Pearson correlation between antioxidant capacity of the collected extracts with the bioactive compounds determined in the extracts (total polyphenolic compounds –TPC-, peptides and free amino acids) was established, being stronger for TPC. The ash content in the solid residue after treatment steadily increased with temperature due to non-solubilization being possible its application in agriculture as fertilizers.

在这项工作中，通过在半连续固定床反应器中使用亚临界水，研究了从倍半乳糖提取琼脂后未充分利用的工业固体残留物的增值。首先，对该副产物进行了完整的表征，确定了高达21％（w / w）的蛋白质含量（氮因子为4.9）和37％（w / w）的必需氨基酸含量。碳水化合物分数和高灰分含量的22％（w / w）。研究了温度在129到200°C之间以及流速在2到6 mL min ^-1之间对蛋白质和碳级分提取/水解的影响。在2 mL min ^-1的恒定流速下，在185°C下获得了最大的蛋白质提取率。较高的温度导致蛋白质或其水解产物的降解。游离氨基酸的释放遵循与蛋白质组分相同的趋势。通过气相色谱法（EZ：faast Phenomenex）测定，对温度最敏感的氨基酸是丝氨酸，天冬氨酸和谷氨酸。结果，通过在高严重性因素下工作，提高了对非极性氨基酸的选择性。建立了收集的提取物的抗氧化能力与提取物中确定的生物活性化合物（总多酚化合物–TPC-，肽和游离氨基酸）之间的Pearson相关性，对TPC而言更强。