M. V. Ruiz-Méndez

Relationships between quality of crude and refined edible oils based on quantitation of minor glyceridic compounds

The relationships between crude and refined oils are examined by quantitation of minor glyceridic compounds, namely, oxidized triglyceride monomers, dimers and diglycerides, associated with oil quality. Particularly, two groups of compounds, i.e. oxidized triglyceride monomers and diglycerides, are of especial interest as they are indicative of oxidative and hydrolytic alterations, respectively. Olive, sunflower and soybean oils differing in initial quality, as evaluated by classical indices and levels of undesirable minor compounds, were subjected to physical and alkali refining in a laboratory system. In all assays, results indicated that amounts of oxidized triglyceride monomers and diglycerides in refined oils remained close to those found in the starting crude oils. Triglyceride dimers were the only group of compounds showing a significant increase, which was dependent on fatty acid composition and initial quality of crude oils. The main conclusion is that quantitation of minor glyceridic compounds in refined oils not only offers a new possibility for quality evalution but also allows the crude oils to be characterised by the presence of markers of oxidative and hydrolytic alterations.

Comparative performance of steam and nitrogen as stripping gas in physical refining of edible oils

Olive, sunflower, and soybean oils were physically refined in a discontinuous laboratory system with either nitrogen or steam as stripping gas during the deodorization step. Comparative assays were also carried out on olive oil in a 10-MT discontinuous industrial plant. Vaporization efficiency of free fatty acids was calculated, and quality of refined oils and composition of deodorizer distillates were analyzed. Results indicated that, in all assays, the efficiency of free fatty acid distillation was higher when nitrogen was used. The amount of nitrogen needed was much lower than that of steam for refined oils of similar high quality. The results also suggested that the amount of stripping gas had a clear influence on the composition of deodorizer distillates because lower quantities of triglycerides and unsaponifiable matter were found when nitrogen was employed.

Serum from postmenopausal women treated with a by-product of olive-oil extraction process stimulates osteoblastogenesis and inhibits adipogenesis in human mesenchymal stem-cells (MSC)

Abstract Aging may enhance both oxidative stress and bone‐marrow mesenchymal stem‐cell (MSC) differentiation into adipocytes. That reduces osteoblastogenesis, thus favoring bone‐mass loss and fracture, representing an important worldwide health‐issue, mainly in countries with aging populations. Intake of antioxidant products may help to retain bone‐mass density. Interestingly, a novel olive‐pomace physical treatment to generate olive oil also yields by‐products rich in functional antioxidants. Thus, diet of postmenopausal women was supplemented for two months with one of such by‐products (distillate 6; D6), being rich in squalene. After treatment, serum from such women showed reduced both lipidic peroxidation and oxidized low‐density lipoprotein (LDL). Besides, vitamin E and coenzyme Q10 levels increased. Furthermore, culture medium containing 10% of such serum both increased osteoblastogenesis and reduced adipogenesis in human MSC from bone marrow. Therefore, highly antioxidant by‐products like D6 may represent a relevant source for development of functional products, for both prevention and treatment of degenerative pathologies associated with aging, like osteoporosis. HighlightsD6 by‐product of olive‐pomace oil refining is rich in bioactive compounds.D6 intake by postmenopausal women reduced lipidic peroxidation and oxidized LDL.D6 intake by postmenopausal women increased vitamin E and CoQ10.D6‐treated‐women serum favors osteoblastogenesis, inhibiting adipogenesis in MSC.D6 intake may protect against aging and osteoporosis.

Production of 4‐ethylphenol in alperujo by Lactobacillus pentosus

BACKGROUND Alperujo is the paste generated from the two-phase extraction system of olive oil. This wet pomace must be stored for several months and, during this period, the formation of 4-ethyphenol provokes a strong off-odour. The aim of this work was to identify the microorganisms able to produce this volatile phenol. RESULTS Yeast and bacterial strains were isolated from stored alperujo and tested for their ability to metabolize p-coumaric acid and form 4-ethylphenol. Among them, Lactobacillus pentosus was the microorganism that both in synthetic medium and alperujo gave rise to 4-ethylphenol formation. This microorganism did not grow in alperujo acidified to pH 2, thereby confirming that acidification as the best method to control odour emissions during alperujo storage. CONCLUSION Lactic acid bacteria, particularly Lactobacillus pentosus, can be responsible for the formation of the off-odour caused by 4-ethylphenol during the storage of alperujo. This odour can be prevented by acidifying the alperujo.

Concentrates of triterpenic acids obtained from crude olive pomace oils: characterization and evaluation of their potential antioxidant activity: Concentrates of triterpenic acids obtained from crude olive pomace oils

BACKGROUND Pentacyclic triterpenic acids (TA) are phytochemicals of increasing nutritional interest owing to their bioactive properties, such as anti-inflammatory, antitumoral, antihyperglycemic and hepatoprotective. Crude olive pomace oils constitute a non-exploited significant source of these compounds. In the present study, concentrates of TA were extracted and characterized from crude olive pomace oils that were obtained by centrifugation and subsequent solvent extraction, respectively. Specifically, the concentrates were obtained from the byproduct generated in the filtration of the oils. The solids were subjected to Soxhlet extractions with hexane to remove the residual oil and then with ethanol for the TA extraction. RESULTS Concentrates containing 850-980 g kg-1 TA were isolated from the oils obtained by centrifugation, whereas those isolated from oils obtained by hexane extraction presented levels of TA that ranged from 510 to 900 g kg-1 . Oleanolic (OA) and maslinic (MA) acids were the TA found in the concentrates. The relative contents of OA and MA were, respectively, 30:70 (w/w) and 77:23 (w/w). All concentrates also presented phenolic compounds at levels of g kg-1 and displayed slight antioxidant properties. CONCLUSION Concentrates of TA, containing MA and OA, can be readily obtained from a byproduct generated by filtration of crude olive pomace oils. Concentrates isolated from oils obtained by centrifugation were rich in MA, whereas those from oils extracted with hexane were rich in OA. The concentrates showed slight antioxidant properties that can be mainly attributed to the presence of phenolic compounds and not to TA.