State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.
Appl Biochem Biotechnol. 2021 Apr;193(4):952-964. doi: 10.1007/s12010-020-03457-w. Epub 2020 Nov 18.
Microalgal oil is considered a promising candidate for edible oils. However, investigation of the refining processes of microalgal oil has been limited, especially deacidification. In this work, microcrystalline cellulose (MCC) was pretreated using different methods and utilized for the first time in the deacidification of microalgal oil. Detection results from FTIR and XRD indicated alkali pretreatment had a significant effect on the structure of MCC. Some inter- and intramolecular hydrogen bonds in AMCC (alkali-pretreated MCC) were destroyed, and crystallinity index of cellulose decreased, which increased its adsorption capacity and the reaction of OH groups with free fatty acids. Some NaOH was adsorbed into AMCC through cellulose swelling, which also contributed to deacidification. The interaction with oil was also improved with many cracks and voids on the surface of AMCC. AMCC could reduce the acid value to about 2 mg KOH/g. Comparatively, original MCC and MCC pretreated with microwave or ultrasound did not exhibit the ability to deacidify. Furthermore, the conditions of alkali treatment were optimized. Treatment with 20% NaOH for 20 min was optimal. Compared with other adsorbents, such as sodium silicate and chitosan treated with alkali and resin, only AMCC could effectively reduce acid value while maintaining high lipid recovery. Therefore, AMCC was considered a better adsorbent for the deacidification of microalgal oil.
微藻油被认为是有前途的食用油候选物。然而，对微藻油精炼工艺的研究还很有限，特别是脱酸。在这项工作中，微晶纤维素（MCC）经过不同的方法预处理，并首次用于微藻油的脱酸。FTIR 和 XRD 的检测结果表明，碱预处理对 MCC 的结构有显著影响。AMCC（碱预处理 MCC）中的一些分子间和分子内氢键被破坏，纤维素的结晶度指数降低，这增加了其吸附能力和 OH 基团与游离脂肪酸的反应性。一些 NaOH 通过纤维素溶胀被吸附到 AMCC 中，这也有助于脱酸。与油的相互作用也得到了改善，因为 AMCC 表面有许多裂缝和空隙。AMCC 可将酸值降低至约 2mg KOH/g。相比之下，原始 MCC 和经微波或超声预处理的 MCC 没有脱酸能力。此外，还优化了碱处理条件。用 20% NaOH 处理 20min 是最佳条件。与其他吸附剂相比，如用碱和树脂处理的硅酸钠和壳聚糖，只有 AMCC 能够在保持高油脂回收率的同时有效降低酸值。因此，AMCC 被认为是微藻油脱酸的一种较好的吸附剂。
