Najari Zahra, Khodaiyan Faramarz, Yarmand Mohammad Saeid, Hosseini Seyed Saeid
Bioprocessing and Biodetection Laboratory, Department of Food Science and Engineering, University of Tehran, Karaj 31587-77871, Iran.
Bioprocessing and Biodetection Laboratory, Department of Food Science and Engineering, University of Tehran, Karaj 31587-77871, Iran.
Waste Manag. 2022 Mar 15;141:208-219. doi: 10.1016/j.wasman.2022.01.007. Epub 2022 Feb 8.
This research aimed to valorize almond hulls based on a zero-waste strategy towards sustainable agricultural developments for the recovery and production of valuable compounds. For this purpose, the potential to produce four products, including pectin (AHP), phenolic compounds (AHPC), pullulan (PUL), and single-cell protein (SCP), was examined. The acidic extraction factors were optimized using a Box-Behnken design for the simultaneous extraction of AHP and AHPC, and the obtained results showed that the maximum AHP (26.32% w/w) and AHPC (6.97% w/w) yields were achieved at 90 °C, pH of 1.4, 58.65 min, and liquid-solid ratio (LSR) of 20.13 v/w as the optimum point. In the next step, the solid residues that remained from the AHP and AHPC extraction process (PESR) were treated with cellulase enzyme and ultrasound and were used for simultaneous microbial production of PUL (34.29-24.56 g/L) and biomass containing SCP (19.31-13.44% w/w). Furthermore, the obtained results showed that AHP was low methylated (26.40%), rich in galacturonic acid (67.88%), and high in molecular weight (595.299 kDa). Also, the investigations of structural properties of AHP and PUL confirmed the presence of chemical structures of these polysaccharides in the formed supernatants. In addition, the AHPC showed considerable antioxidant activity compared with ascorbic acid (ASC) and BHA.
本研究旨在基于零废物策略实现杏仁壳的价值最大化，以促进可持续农业发展，回收和生产有价值的化合物。为此，研究了生产四种产品的潜力，包括果胶（AHP）、酚类化合物（AHPC）、普鲁兰多糖（PUL）和单细胞蛋白（SCP）。采用Box-Behnken设计优化酸性提取因子，以同时提取AHP和AHPC，所得结果表明，在90°C、pH值为1.4、58.65分钟和液固比（LSR）为20.13 v/w的最佳条件下，AHP（26.32% w/w）和AHPC（6.97% w/w）的产量最高。下一步，将AHP和AHPC提取过程中剩余的固体残渣（PESR）用纤维素酶和超声波处理，并用于同时微生物生产PUL（34.29 - 24.56 g/L）和含SCP的生物质（19.31 - 13.44% w/w）。此外，所得结果表明，AHP甲基化程度低（26.40%），富含半乳糖醛酸（67.88%），分子量高（595.299 kDa）。此外，对AHP和PUL结构性质的研究证实了这些多糖的化学结构存在于形成的上清液中。此外，与抗坏血酸（ASC）和丁基羟基茴香醚（BHA）相比，AHPC表现出相当的抗氧化活性。
