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Valuable Compounds Extraction from Cereal Waste and By-Products
Published in Francisco J. Barba, Elena Roselló-Soto, Mladen Brnčić, Jose M. Lorenzo, Green Extraction and Valorization of By-Products from Food Processing, 2019
Manuel Viuda-Martos, Juana Fernández-López, José Angel Pérez-Álvarez
Plant sterols are essential components of cell membranes and are present in all plants. They are structurally comparable to cholesterol, with differences in the lateral chain attached to the steroid ring (Carr and Jesch, 2006). All sterols have a chemical structure formed by four joined rings of 1,2-cyclopentano-pehydrophenantren with hydroxyl group located in the position C3. In nature, it is possible to find more than 200 different compounds that can be classified as sterols. The difference between them is in the chemical structure of the side chain as well as the position in which the double bond is found in the fused ring (Bartłomiej et al., 2012). In cereal grains, the principal sterols include sitosterol, campesterol, stigmasterol, and brassicasterol (Figure 6.5a) (Nyström et al., 2008). Stanols are saturated sterols and are much less abundant in nature than the corresponding sterols. Plant stanols comprise about 5–10% of the total sterol/stanol mixture naturally present in the human diet (Valsta et al., 2004). The principal stanols of cereal grains (Figure 5b) are stigmastanol and campestanol, the concentration of both can reach up to 10–30% of the total of sterols present in the cereal (Piironen et al., 2002). In cereal grains, these compounds can be found mainly in the bran and the germ (Jiang and Wang, 2005; Nurmi et al., 2012). Many by-products generated in the industrialization of cereals present a considerable content of these bioactive compounds and could become potential sources of food ingredients for the development of functional foods that could have beneficial effects on health (Jiang and Wang, 2005; Wanyo et al., 2014).
Synthesis of biocatalyst in microfluidic reactor for β-sitosterol esterification
Published in Chemical Engineering Communications, 2023
Fiona W.M Ling, Hayder A. Abdulbari, Chin Sim-Yee, Wafaa K. Mahmood
Phytosterols are naturally occurring molecules present in plant membranes that feature a four-ring steroid nucleus, a 3β-hydroxyl group, and a 5,6-double bond. The existence of an additional ethyl (β-sitosterol) or methyl (campesterol) group at C-24, or an extra double bond (stigmasterol) at C-22, distinguishes phytosterols from other types of sterols (Micallef and Garg 2009). It has been claimed that phytosterols can remarkably reduce cholesterol absorption by up to 50% (Jones et al. 2000), thus, phytosterols are important as cholesterol lowering agents that can be used as a substitution of dietary cholesterol in food, cosmetic and pharmaceutical industries. Findings proved that daily intake of phytosterols at 0.6–0.33 g can decrease the low-density lipoprotein (LDL) cholesterol concentration by 6–12% (Ras et al. 2014) where reduction of 1% of LDL cholesterol can decline 1% of the occurrence of coronary heart disease (LaRosa 2007). It is believed that the phytosterols compete with the dietary cholesterol that minimize the absorption of dietary cholesterol in the digestive system (Garti et al. 2006). This resulting in excretion of the cholesterol that would minimize the solubility of cholesterol in the intestines (Ling and Jones 1995; Smet et al. 2012) while the adsorbed phytosterols are digested by the liver rapidly (Micallef and Garg 2009).
Solid-phase extraction of phytosterols from rapeseed oil deodorizer distillates with magnetic graphene oxide nanocomposite
Published in Journal of Experimental Nanoscience, 2020
Parisa Jafarian-asl, Razieh Niazmand, Moslem Jahani
The RODD sample was treated in a CO2 supercritical fluid extraction (SFE) system (the experimental conditions previously described in our previous work [46] followed by GC-MS analysis of the final extract. The results (Figure 4a) showed the sterols are purified, and the extract contains 65 wt% phytosterols includes β-sitosterol, campesterol, and brassica sterol. The non-polar nature of carbon dioxide leads phytosterols to transfer to the extract while the polar components remain in the raffinate. Then, the proposed SPE method was performed with SFE extract as the initial sample and under optimized conditions. The results (Figure 4b) showed the separation of β-sitosterol by adsorbent with a final recovery of 86%. It demonstrates the feasibility of the suggested method for the purification and determination of β-sitosterol in DOD.