Carmen Soto

Enzymic pre-treatment of Guevina avellana mol oil extraction by pressing

Abstract Cosmetic oil of Guevina avellana mol is industrially extracted by cold pressing, producing a residual meal with 10–12% on dry base of oil, which spoils, limiting its application for human consumption. An enzymic pre-treatment was incorporated into the conventional oil extraction process by cold pressing, with the purpose of improving the oil yield and the residual meal quality. The effect of enzyme/substrate ratio, temperature and moisture was analysed during hydrolysis using two commercial enzyme mixtures. Pressing conditions during this stage were also studied. An increase in extracted oil was obtained for both enzymic mixtures. The best result was a yield up to 98% of extracted oil and residual meal with 1.5% of oil. An oil extraction yield up to 98% and a residual meal with 1.5% of oil. This result was further validated in an industrial plant scale.

Characterisation of protein concentrates from pressed cakes of Guevina avellana (Chilean hazelnut)

Protein concentrates, produced by aqueous extraction and membrane filtration from Guevina avellana pressing cakes, were characterized with regard to nutritional and functional properties. The effect of a previous enzymatic treatment, carried out with the aim of enhancing oil extractability during pressing, was also evaluated. Thermal conditioning of the seeds, before pressing, influenced oil and protein extractability, as well as the nutritional quality and functional properties. The protein concentrates contained up to 65% protein with an in vitro apparent digestibility coefficient in the range 75–80%. They presented a reduced ability to bind water, but they retained almost up to ten times their weight of oil.

The enhancement of antioxidant compounds extracted from Thymus vulgaris using enzymes and the effect of extracting solvent

We evaluate the total phenolic compounds (TPC) content and the antioxidant activity (AA) of extracts obtained from ground fresh thyme (FT) and depleted thyme (DT), a by-product of the process of essential oil extraction. In addition, enzymatic treatments were evaluated to improve the extraction yields of polyphenolic compounds from thyme. Extractions were performed using several solvents as methanol, ethanol, and water. Enzymes were applied prior to extraction or during the extraction process. The best results were obtained using a mixture of methanol and water, resulting in 2790 and 220 mg Gallic acid equivalent (GAE)/L of TPC for FT and DT, respectively. A similar result was observed for AA. With regard to enzymatic treatment, application of Grindamyl CA 150 enzyme as a pre-treatment resulted in the production of an extract from DT with 614 mg TE (trolox equivalent)/L of AA, 70% more than the control, and an AA of 621 mg TE/L (74% more than the control sample) was obtained using Grindamyl CA 150 during the extraction process. These results suggest that enzymatic treatment is an interesting alternative for producing antioxidant extracts from DT.

Potential use of avocado oil on structured lipids MLM-type production catalysed by commercial immobilised lipases.

Structured Lipids are generally constituents of functional foods. Growing demands for SL are based on a fuller understanding of nutritional requirements, lipid metabolism, and improved methods to produce them. Specifically, this work was aimed to add value to avocado oil by producing dietary triacylglycerols (TAG) containing medium-chain fatty acids (M) at positions sn-1,3 and long-chain fatty acids (L) at position sn-2. These MLM-type structured lipids (SL) were produced by interesterification of caprylic acid (CA) (C8:0) and avocado oil (content of C18:1). The regiospecific sn-1,3 commercial lipases Lipozyme RM IM and TL IM were used as biocatalysts to probe the potential of avocado oil to produce SL. Reactions were performed at 30–50°C for 24 h in solvent-free media with a substrate molar ratio of 1∶2 (TAG:CA) and 4–10% w/w enzyme content. The lowest incorporation of CA (1.1% mol) resulted from Lipozyme RM IM that was incubated at 50°C. The maximum incorporation of CA into sn-1,3 positions of TAG was 29.2% mol. This result was obtained at 30°C with 10% w/w Lipozyme TL IM, which is the highest values obtained in solvent-free medium until now for structured lipids of low-calories. This strategy opens a new market to added value products based on avocado oil.