Supercritical natural antioxidants

Nguyen, U., Evans, G. and Frakman, G. 1994. Natural antioxidants produced by supercritical extraction. In Supercritical Fluid Processing of Food and Biomaterials. Rizvi, S.S.H. (Ed.) Glasgow, UK Blackie Academic and Professional, p. 103. 

Tena, M.T., Valcarel, M., Hidalgo, PJ. and Ubera, J.L. 1997. Supercritical fluid extraction of natural antioxidants from rosemary comparison with liquid solvent sonication. Analytical Chem. 69 521-526. 

The effectiveness of the two natural antioxidants rosemary and sage increases with the content of the active phenolic diterpenes [2-3]. New and improved extraction techniques based on supercritical C02-extraction (see chapter 2.1.2) resulted not only in concentrated and very active, but also in well desodourized and almost neutral tasting antioxidants. 

This invention is concerned with a process to remove the aroma constituents from roasted coffee. The prior art discussion brings out that although liquid CO2 can also extract the aroma substances, it does not extract the natural antioxidants that are present in roasted coffee. The extracted oils, therefore, are not stable. Supercritical CO2 can extract the natural antioxidants along with the oils. 

Tena, M, Valcarcel, M, Hidalgo, P and Ubera, J (1997) Supercritical fluid exb-action of natural antioxidants from rosemary comparison with bquid solvent sonication. Anal. Chem., 69, 521-526. 

Most interesting investigations in this field include different approaches to the biorefinery concept involving cottonseed. To serve as an example, Zhu et al. proposed the production of biodiesel, sterols, gossypol, and raffinose and nontoxic cottonseed meal in an integrated biorefinery, by a two-phase extraction process, using supercritical methanol (Zhu et al., 2014). Simultaneous production of alpha-tocopherol (a natural antioxidant) and FAME was also presented as a viable biorefinery concept (Zhu et al., 2012). 

Supercritical fluid extraction (SFE) has been widely used to the extraction processes in pharmaceutical industries. Besides application of SFE in phannaceuticals, it has been applied on a wide spectmm of natural products and food industries such as natural pesticides, antioxidants, vegetable oil, flavors, perfumes and etc [1-2]. 

Another processing procediue that could involve supercritical fluid extraction with CO2 is the preparation of flavor concentrates from meat lipids for use in mixtures of other natural precursors for the preparation of tynthetic meat flavor additives that serve bofii as antioxidants that prevent warmed-over flavor (WOF) in cooked meat diuing storage and enhance the flavor of the natural products. 

With the increasing interest in the food industry for natural sources of antioxidants for their beneficial effects on health, new potential sources have been screened among edible aromatic plants and microalgae. The cc-tocopherol content (a potent antioxidant) in parsley was reported to be 3.45mg/100g of fresh leaves obtained through supercritical fluid extraction (Diego et al., 2004). 

Ultrasound-assisted leaching has also been used to extract natural compounds such as vitamins A, D and E from feeds [57], paclitaxel and related taxoids from leaf tissue of Taxus [58], opiates from hair samples [59] and antioxidants from rosemary [60]. Ultrasounds have so far had much more restricted application in this field than in the previous ones, possibly as a result of the technique being at a disadvantage with respect to alternatives such as microwave-assisted extraction [57] or supercritical CO, extraction [60]. 

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