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Beeswax oleogels (OGs), with a mechanical strength similar to pork backfat, were formulated with avocado (A), sunflower (S), and linseed (L) oils, applying a central composite design plus star point, and were evaluated as oral delivery vehicles of curcuminoids (OGACur, OGSCur, OGLCur). The incorporation of curcumin into the OG matrix significantly delayed both the formation of peroxides and conjugated trienes (K268 values), and the degradation rate of curcumin decreased with the increase of the oil polyunsaturated fatty acids (PUFA) content. The oil structuring did not affect the bioaccessibility of curcuminoids (>55% in all the OGs, regardless of the oil type), but it did reduce the release of fatty acids (~10%) during in vitro gastrointestinal digestion. The intestinal absorption, evaluated in Caco-2 cell monolayers, was higher for the micelle-solubilized curcumin from the digested OG than from unstructured oils, and it showed high anti-inflammatory potential by inhibiting the tumor necrosis factor-α (TNF-α) production compared to the positive control, both before and after the stimulation of ThP-1 cells with LPS. Regardless of the oil type, these beeswax-based OGs with gel-like behavior designed as fat replacers may be promising vehicles for the oral delivery of curcuminoids.

Omega-3 rich vegetable oils, such as walnut oil, are gaining interest because of their health benefits. Synthetized homologous series of hydroxytyrosol alkyl esters (HTEs) with different alkyl chain lengths (C4-C18) were incorporated in purified walnut oil (PWO) spray-dried microparticles, designed with Capsul® (C) as encapsulating agent and sodium alginate (SA) as outer layer (PWO-C/SA). The encapsulation efficiency (>87%) and Tg of PWO-C/SA microparticles were not affected by the HTEs. The incorporation of HTE-C10 increased the melting point (185.0 ± 1.3 °C), decreasing the formation of Dimers + Polymers (1.12 ± 0.05% at day 35 of storage) and the crystallinity of the microparticles (>170 °C). The highest stability of PWO-C(HTE-C10)/SA suggests a specific location of HTE-C10 at the oil:water interface. The SA layer delayed the release of fatty acids during in vitro digestion. The incorporation of HTEs of medium chain length can be a suitable strategy to protect unsaturated oils encapsulated by spray-drying.

Food behavior during oral processing plays an essential role in the perception of texture. It depends on different factors, including food structure and composition, as well as its behavior when interacting with saliva. This study aimed to investigate the effect of particle size and thickener type of emulsified systems on physical, rheological, tribological, and oral oily coating properties under oral conditions. Six matrices based on oil-in-water emulsions with different particle sizes (NE-nanoemulsion and CE-conventional emulsions) were prepared using a mixture of emulsifiers (10% w/w) and sunflower oil (10% w/w). Thickened agents were added to the matrices (NE and CE) at different concentrations (3–4.5% w/w of starch-ST or 0.4–0.8% w/w xanthan gum-XG) to obtain equi-viscous samples (NE-EV) with their CE-based counterpart. Results showed a decrease in apparent viscosity values under oral conditions (saliva and shearing at 10 s−1) during the shear time, but this behavior was more evident in starch-based matrices. The lubrication properties of the different matrices depended mainly on the thickener concentration since equi-viscous samples (NE-ST-EV and NE-XG-EV) showed higher coefficient of friction (CoF) values. Finally, oral oily coating was more related to the oil droplets size than to the type of thickener since all NE-based matrices showed a higher amount of coating retained compared to the CE-based ones. Therefore, NE-based matrices could be used as an alternative to increase mouthfeel sensations in food emulsions.

Hydroxypropyl-inulin (HPI) was synthetized from inulin by etherification. The hydroxypropylation of inulin (degree of substitution 0.7) was confirmed by 1H NMR. The replacement of hydroxyl groups in inulin by an ether linkage increased its hydrophobicity, making HPI suitable as a novel encapsulating agent of fish oil (FO) by both conventional and water-free spray drying. FO microparticles were designed according to a composite central plus star statistical design. A FO-in-water emulsion was prepared as infeed for encapsulation by conventional spray drying (FO-csd), whereas FO was dispersed in methanol for encapsulation by water-free spray drying (FO-wfsd). The encapsulation efficiency of FO was similar in both FO-csd and FO-wfsd microparticles (80.5% and 82.6%, respectively), despite the different encapsulation mechanism. FO-wfsd microparticles showed lower glass transition temperature (Tg), hygroscopicity, moisture and water activity (aw) than FO-csd microparticles. Only the superficial FO was released from FO-wfsd microparticles (at pH 4.6 and 6.5) and FO-csd (at pH 6.5), which is desirable in the design of healthy food liquid matrices. Furthermore, FO-csd microparticles showed lower oxidative stability than FO-wfsd microparticles evaluated by the formation and distribution of polar compounds, suggesting that water had a higher plasticizing effect than methanol and provided FO microparticles with poor film-forming properties. The type of solvent determined the FO encapsulation mechanism but slightly affected the physico-chemical properties of the microparticles, the oxidative stability and the FO released pattern.

Purified walnut oil (PWO) microparticles with Capsul® (C, encapsulating agent), sodium alginate (SA) as outer layer and ascorbic acid (AA) as oxygen scavenger were obtained by spray drying using a three-fluid nozzle. AA was incorporated in the inner infeed (PWO-C(AA)/SA), in the outer infeed (PWO-C/SA(AA)) and in both infeed (PWO-C(AA)/SA(AA)). PWO-C(AA)/SA (4.56 h) and POW-C(AA)/SA(AA) (2.60 h) microparticles showed higher induction period than POW-C/SA(AA) (1.17 h), and lower formation of triacylglycerol dimers and polymers during storage (40 °C). Therefore, AA located in the inner infeed improved the oxidative stability of encapsulated PWO by removing the residual oxygen. AA in the SA outer layer did not improve the oxidative stability of encapsulated PWO since oxygen diffusion through the microparticles was limited and/or AA weakened the SA layer structure. The specific-location of AA (inner infeed) is a strategy to obtain stable spray-dried polyunsaturated oil-based microparticles for the design of foods enriched with omega-3 fatty acids.

The effect of the physical state of flavonoid-inulin microparticles (semi-crystalline/amorphous) on the oxidative stability of lipid matrices was studied. Epicatechin (E) and quercetin (Q) microparticles with inulin were formulated at two infeed temperatures (15 °C and 90 °C) by spray drying. X-ray diffraction analyses showed that flavonoid-inulin microparticles obtained at feed temperature of 15 °C were semi-crystalline (E-In-15, 61.2% and Q-In-15, 60%), whereas those at 90 °C were amorphous (Q-In-90, 1.73 and Q-In-90 2.30%). Semi-crystalline state of flavonoid-inulin microparticles enhanced the EE (68.8 and 67.8% for E and Q, respectively) compared to amorphous state (41.6 and 51.1% for E and Q, respectively). However, amorphous Q-microparticles showed the highest antioxidant activity both in methyl linoleate and sunflower oil, increasing the induction period and decreasing the polar compounds and polymer triglyceride formation during long-term oxidation study. Therefore, the physical state of spray-dried flavonoid-inulin microparticles may determine their antioxidant activity in lipid matrices.

Fish oil (FO) was encapsulated by conventional spray-drying (FO-W-Lec) and by ethanol spray-drying, with FO incorporated as an oil-in-ethanol emulsion (with lecithin as emulsifier, FO-EtOH-Lec) or as an oil-in-ethanol dispersion (without lecithin, FO-EtOH). FO-EtOH-Lec and FO-W-Lec were obtained according to a central composite design, whereas FO-EtOH was prepared under optimal conditions. The optimal FO/hydroxypropylcellulose ratio was 1:4 for all FO-systems, but the optimal inlet gas temperature was lower for FO-EtOH and FO-EtOH-Lec (135 °C) than for FO-W-Lec (200 °C). The encapsulation efficiency (EE) for ethanol spray-drying (FO-EtOH-Lec, 81.1% and FO-EtOH, 80.4%) was higher than conventional spray-drying (71.1%). However, the FO stability was better for FO-EtOH-Lec, measured either by total oxidation compounds or by polymerization compounds. The FO released in aqueous models corresponded only to surface FO in all FO-systems, showing Fickian diffusion. Ethanol spray-drying is an alternative to conventional methods, increasing the EE values of FO. Furthermore, lecithin allows improving the FO stability when incorporated as an emulsifier in ethanol spray-drying.

Fish-oil (FO) was encapsulated with hydroxypropylcelullose (HPC) by conventional spray-drying with water (FO-water) and solvent spray-drying with ethanol (FO-EtOH), methanol (FO-MeOH) and acetone (FO-Acet) in order to study the effect of the solvent on the encapsulation efficiency (EE), microparticle properties and stability of FO during storage at 40 °C. Results showed that FO-Acet presented the highest EE of FO (92.0%), followed by FO-EtOH (80.4%), FO-MeOH (75.0%) and FO-water (71.1%). A decrease of the dielectric constant increased the EE of FO, promoting triglyceride-polymer interactions instead of oil-in-water emulsion retention. FO release profile in aqueous model was similar for all FO-microparticles, releasing only the surface FO, according to Higuchi model. Oxidative stability of FO significantly improved by spray-drying with MeOH, both in surface and encapsulated oil fractions. In conclusion, encapsulation of FO by solvent spray-drying can be proposed as an alternative technology for encapsulation of hydrophobic molecules.

The development of fat replacers to obtain healthier/functional foods is a constant challenge. With this aim, double emulsions (DE) with a blend of olive, linseed and fish oils as oil phase were developed. To prevent the oxidation of these oils, gallic acid and quercetin were incorporated in the internal and the external aqueous phase (W), respectively, according to a factorial design. Considering the low solubility of quercetin in water, it was included in O/W nanoemulsions (QN), thus being freely dispersible in W. The antioxidant activity in DE was attributed to QN, which significantly improved the oxidative stability of DE/QN. Furthermore, DE/QN showed good physical stability with a limited coalescence during storage at 4 °C for 28 days, significantly longer than time usually required for food ingredients. Therefore, DE/QN could be used as potential fat replacer in a variety of food formulations, providing blends of fatty acids consistent with dietary recommendations.

Olive leaves (Olea europaea L.) are one of the main by-products generated from olive oil industry. Oleuropein (OE) is the major polyphenol described in olive leaves extracts. Encapsulation and controlled release of bioactive compounds such as polyphenols is one of the main potential applications of W1/O/W2 double emulsions (DE) in the food industry. By suitable formulation of the lipid phase, DEs could be used as fat replacers in the development of healthier or functional foods with lower content of saturated fatty acids and higher content of unsaturated fatty acids. The aim of this work was the incorporation of DEs, with a healthier fatty acids profile and an olive leave extract (OLE) encapsulated in the internal aqueous phase (W1), in meat model systems (MMS) as fat ingredient, in replacement of pork backfat. A blend of olive, linseed and fish oils (70:20:10) was used as lipid phase in DE. For comparative purposes, MMS with pork backfat, MMS with vacuum DE as fat ingredient and MMS with unencapsulated OLE were also prepared. The oxidative stability (peroxide value), antioxidant capacity (FRAP and DPPH), and OE content of the MMS were analyzed for 7 days at 60 ºC. A great oxidative stability was observed for MMS with OLE (both unencapsulated and encapsulated in W1) until day 5 of storage, showing lower peroxide values than MMS with pork backfat or vacuum DE. However, a large increase of peroxide value together with a large decrease in DPPH and FRAP values were observed for MMS with unencapsulated OLE at day 7 of storage, as a consequence of the sharply decrease that took place in the OE content. DEs rich in unsaturated fatty acids and OLE showed a high oxidative stability and antioxidant capacity, and may be used as fat replacers in the development of healthier meat products.

La principal fuente de ácidos grasos de cadena larga omega-3 (AGPICL) es el aceite de pescado (AP), diversos estudios confirman los efectos positivos de EPA y DHA en la salud de los seres humanos. Sin embargo, AGPICL son altamente susceptibles a oxidación. La microencapsulación de AP es una herramienta para retardar la oxidación siendo el secado por atomización el método más utilizado, siendo el secado por atomización con solvente (SAS), una alternativa que utiliza bajas temperaturas y nitrógeno como gas de secado. El objetivo fue encapsular AP y una emulsión de AP con hidroxipropilcelulosa (HPC) por SAS-etanol (AP-HPC-E y AP-L-HPC-E, respectivamente) para estudiar el efecto de la emulsión sobre la estabilidad y la liberación del AP en un modelo acuoso. Para elaborar la emulsión se aplicó un diseño experimental evaluando el contenido de L y la velocidad de homogeneización como variables independientes sobre el tamaño de gota de la emulsión. Posteriormente se aplicó un diseño experimental composito central más punto axial para la encapsulación mediante SAS. Las variables independientes fueron temperatura secado y relación AP/HPC, y las respuestas eficiencia de encapsulación (EE) y rendimiento (Y) del proceso. Las micropartículas de AP se caracterizaron por humedad, aw, higroscopicidad, tamaño de partícula, morfología y estabilidad del AP encapsulado a 40ºC medida por compuestos polares (CP). Las condiciones óptimas de temperatura de secado y relación AP/HPC fueron 135oC y 1:3 para AP-HPC-E y 135oC y 1:4 para AP-L-HPC-E. El sistema con emulsión AP-L-HPC-E mostró una mayor EE (83%) y una menor formación de CP a las 18 h de almacenamiento (19%) respecto al sin emulsión (76% de EE y 24% de CP). La liberación del AP en sistemas acuosos a pH 4,6 y 6,5 correspondió solamente al AP dispuesto en la superficie de la micropartícula a los 106 días de almacenamiento a 30ºC.

El aceite de pescado (AP) es la principal fuente de ácidos graso poliinsaturados de cadena larga omega-3. El EPA tiene efectos sobre la prevención de enfermedades cardiovasculares y el DHA juega un rol en la nutrición infantil y el desarrollo neuronal. Sin embargo, el principal inconveniente del aceite de pescado, es su alta susceptibilidad a la oxidación. La microencapsulación de AP por secado por atomización convencional (SAC) ha sido propuesta como la estrategia más utilizada para corregir estos inconvenientes. Para su realización, es necesaria la elaboración de una emulsión, siendo una alternativa el secado por atomización con solvente (SAS) donde no se requiere la elaboración de una emulsión. El objetivo de este trabajo fue estudiar la encapsulación de AP por SAS y el efecto del solvente sobre sobre la eficiencia de encapsulación (EE) y estabilidad del AP encapsulado durante el almacenamiento a 40ºC. Las micropartículas de AP se elaboraron con hidroxipropilcelulosa (HPC) por SAC y SAS. Las micropartículas de AP obtenidas por SAC se prepararon utilizando una emulsión o/w, usando lecitina de soya como emulsificante (W-HPC). En el caso de las micropartículas de AP por SAS, se utilizó etanol (E-HPC), metanol (M-HPC) y acetona (A-HPC). Los resultados mostraron que la EE% para A-HPC (97,8%) fue significativamente superior a los sistemas E-HPC, M-HPC y W-HPC (80,5; 73,3 y 77,9%) respectivamente. El estudio de estabilidad del aceite de pescado encapsulado mostró una menor formación de compuestos polares en el sistema con acetona (11%), respecto a los sistemas con etanol (23%), metanol (27%) y convencional (23%). El sistema con acetona presentó la más alta EE y estabilidad del AP, respecto a los sistemas con etanol y metanol, lo cual se puede atribuir a la mayor constante dieléctrica de la acetona que aumenta la solubilidad del HPC y mejora la interacción triglicérido-polímero.

The objective of this work was to evaluate the antioxidant action of flavonoids with specific differences in chemical structure, namely, quercetin (Q), epicatechin (E) and naringenin (N), in bulk methyl linoleate (ML) under different oxidation conditions at 60 °C, in an oven and in a Rancimat apparatus. The oxidation kinetics were studied by direct and concomitant analysis of primary and secondary oxidation compounds. Addition of 200 mg/kg of E or Q to ML increased about tenfold the oxidative stability of ML. The protective effect was significantly higher for E, independent of the oxidation conditions used. However, N showed no effect. Results obtained were attributed to differences in structural features and polarity. Thus, the presence of the ortho-dihydroxy structure in the B ring and the 3-hydroxyl group in the C ring of E and Q seemed to be determinant and the comparatively higher polarity of E may have enhanced its antioxidant efficiency.

Microencapsulated quercetin (Q) and epicatechin (E) were prepared by spray-drying using inulin (IN) as encapsulating agent (Q–IN and E–IN) as well as with Capsul (C) as channelizing agent (Q–IN–C and E–IN–C). Microparticles were added to methyl linoleate (ML) and results showed that Q microparticles markedly improved its oxidative stability by increasing the induction period values and delaying the formation of oxidation compounds, as determined by high-performance size-exclusion chromatography, with respect to E microparticles, thus suggesting the importance of flavonoid C-ring substitution. Remaining levels of Q in the lipid system throughout oxidation of ML added with Q microparticles seemed to show two releasing zones: the first one corresponds to the equilibrium zone, when Q released from microparticles replaces Q that is being degraded; the second zone corresponds to the degradation of Q, when the release rate of the encapsulated Q is slower than its degradation rate. In contrast, E microparticles showed only one zone corresponding to the release of surface E. The end of the induction period was in line with the exhaustion of Q and E and the initiation of formation of advanced oxidation products (polymers). In conclusion, Q microparticles have a potential application to extend the shelf-life of lipid matrixes.

Quercetin (Q) and epicatechin (E) microparticles were designed using an oil-insoluble polymer (inulin [In]) as encapsulating agent and with or without an oil-soluble polymer (soy protein isolate [SPI]) by spray-drying. Encapsulation efficiencies were significantly higher for the E systems than for Q systems, suggesting that the spatial arrangement may affect the hydroxyl groups availability to form hydrogen bonds. The microencapsulated flavonoids were added to sunflower oil (SO) in order to evaluate its oxidative stability. The induction period (IP) of SO, determined in Rancimat at 60°C, significantly increased when Q-microparticles with or without SPI were added, showing those with SPI the highest IP value. In the case of E systems, the IP of SO increased only when E–In microparticles with SPI were added. These results suggest that SPI may favor the diffusion of flavonoids to the lipid medium by the formation of channels into the microparticles. The channels formation was observed for Q–In–SPI and E–In–SPI by a confocal laser scanning microscopy study. Additional oxidation studies under conditions of lower oxygen availability resulted in overall more retarded oxidation and no clear effect of SPI incorporation was observed.

In the last 10 years, interest in research on polyphenol-rich fruit species has increased due to the potential health benefits of these species, mainly attributed to their high anthocyanin content and antioxidant activity. Six polyphenol-rich fruit species (blueberries, raspberries, blackberries, strawberries, pomegranates and maqui berries) were harvested at the same maturity stage during the same growing season and were compared according to their total phenolic (Folin-Ciocalteu method) and total anthocyanin (pH differential method) contents and antioxidant activity using ferric-reducing antioxidant power (FRAP assay) and 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging capacity methods. With the results of this study, the polyphenolic status of the main polyphenol-rich fruit species that are grown in Chile were compared, and maqui berry showed the highest total phenolic (14.6 g gallic acid equivalent kg-1 of fresh weight [g GAE kg-1 FW]), total anthocyanin (9.3 g cyanidin-3-glu kg-1 of fresh weight [g cy-3-glu kg-1 FW]) contents, and antioxidant activity (152.0 mmol Fe²+ kg-1 of fresh weight [mmol Fe²+ kg-1 FW] and 1.5 mg of fresh weight [FW]) with significant differences from the other fruit species that were analyzed. Nevertheless, bioavailability studies to test the benefits of the species' dietary antioxidants should be performed in order to establish scientific evidence in this area., Durante los últimos 10 años, el interés en la investigación de los frutos ricos en polifenoles ha incrementado debido a sus potenciales efectos beneficiosos para la salud atribuidos principalmente a contenidos altos de antocianinas y una alta actividad antioxidante. Seis especies de frutos ricos en polifenoles (arándanos, frambuesas, moras, frutillas, granadas y maquis) fueron cosechados en el mismo estado de madurez durante la misma temporada de producción y comparadas de acuerdo a sus contenidos de fenoles totales (método Folin Ciocalteu), antocianinas totales (método pH diferencial) y actividad antioxidante determinada por los métodos de FRAP (poder antioxidante para reducir el hierro férrico) y del radical DPPH (2,2-diphenylpicrylhydrazil). Los resultados de este estudio permiten comparar el estatus polifenólico de los principales frutos ricos en polifenoles que crecen en Chile, donde el maqui presenta el mayor contenido de fenoles totales (14,6 g EAG kg-1 pf), antocianinas totales (9,3 g ci-3-glu kg-1 pf), y actividad antioxidante (152,0 mmol Fe+² kg-1 and 1,5 mg pf) con diferencias significativas con las otras especies de frutos analizadas. Sin embargo, se deben realizar estudios de biodisponibilidad para probar los efectos benéficos sobre la salud humana de los antioxidantes de esta especie para poder establecer evidencia científica en esta área.

In the last 10 years, interest in research on polyphenol-rich fruit species has increased due to the potential health benefits of these species, mainly attributed to their high anthocyanin content and antioxidant activity. Six polyphenol-rich fruit species (blueberries, raspberries, blackberries, strawberries, pomegranates and maqui berries) were harvested at the same maturity stage during the same growing season and were compared according to their total phenolic (Folin-Ciocalteu method) and total anthocyanin (pH differential method) contents and antioxidant activity using ferric-reducing antioxidant power (FRAP assay) and 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging capacity methods. With the results of this study, the polyphenolic status of the main polyphenol-rich fruit species that are grown in Chile were compared, and maqui berry showed the highest total phenolic (14.6 g gallic acid equivalent kg-1 of fresh weight [g GAE kg-1 FW]), total anthocyanin (9.3 g cyanidin-3-glu kg-1 of fresh weight [g cy-3-glu kg-1 FW]) contents, and antioxidant activity (152.0 mmol Fe²+ kg-1 of fresh weight [mmol Fe²+ kg-1 FW] and 1.5 mg of fresh weight [FW]) with significant differences from the other fruit species that were analyzed. Nevertheless, bioavailability studies to test the benefits of the species' dietary antioxidants should be performed in order to establish scientific evidence in this area., Durante los últimos 10 años, el interés en la investigación de los frutos ricos en polifenoles ha incrementado debido a sus potenciales efectos beneficiosos para la salud atribuidos principalmente a contenidos altos de antocianinas y una alta actividad antioxidante. Seis especies de frutos ricos en polifenoles (arándanos, frambuesas, moras, frutillas, granadas y maquis) fueron cosechados en el mismo estado de madurez durante la misma temporada de producción y comparadas de acuerdo a sus contenidos de fenoles totales (método Folin Ciocalteu), antocianinas totales (método pH diferencial) y actividad antioxidante determinada por los métodos de FRAP (poder antioxidante para reducir el hierro férrico) y del radical DPPH (2,2-diphenylpicrylhydrazil). Los resultados de este estudio permiten comparar el estatus polifenólico de los principales frutos ricos en polifenoles que crecen en Chile, donde el maqui presenta el mayor contenido de fenoles totales (14,6 g EAG kg-1 pf), antocianinas totales (9,3 g ci-3-glu kg-1 pf), y actividad antioxidante (152,0 mmol Fe+² kg-1 and 1,5 mg pf) con diferencias significativas con las otras especies de frutos analizadas. Sin embargo, se deben realizar estudios de biodisponibilidad para probar los efectos benéficos sobre la salud humana de los antioxidantes de esta especie para poder establecer evidencia científica en esta área.

Quercetin (Q), naringenin (N) and epicatechin (E) were encapsulated with inulin (In) as encapsulating agent and Capsul (C) as channelizing agent by spray drying and applying a Box-Behnken design. Q-In, N-In, E-In, Q-In-C, N-In-C and E-In-C were characterised by encapsulating efficiency (EE) and their release profile in methyl linoleate (ML). The flavonoid EE was significant higher (p<. 0.05) for Q and E (over 60%) than for N (≈. 40%) in microparticles either without or with channelizing agent. An increase of the number of flavonoid hydroxyl groups enhanced EE, showing the influence of the flavonoid structural features. The release profile was fitted to Peppas and Higuchi mathematical models. The highest and lowest flavonoid release rate constants were found for N and E, respectively, for microparticles both with and without channelizing agent. The EE as indicator of flavonoid-inulin interaction was inversely related with the release rate constant in ML. Flavonoid release rate constant was significantly higher for microparticles with channelizing agent than for those without it, suggesting that Capsul induces the formation of channels inside the microparticles thus favoring the diffusion of flavonoids to ML. The mechanism of flavonoid release was only determined by channelizing agents, independently of the flavonoid nature, that is, Fickian and non-Fickian diffusion mechanisms in microparticles with and without Capsul, respectively. © 2014 Elsevier Ltd.

Se estudia la evolución de la oxidación a 60º C en patatas fritas con cuatro aceites vegetales de distinta relación ácidos grasos poliinsaturados/saturados (P/S): 5,4 para el aceite de girasol, 3,4 para el aceite de canola, 0,4 para una mezcla de oleína de palma (80 %) y aceite de canola (20 %) y 0,3 para la oleína de palma. Se estudia igualmente la influencia de la adición de palmitato de ascorbilo (AP) durante la conservación del producto frito con especial atención a su efecto sinergista sobre los antioxidantes naturales. La evolución de la oxidación en lotes de patatas, con y sin adición de AP, se determinó mediante las siguientes determinaciones analíticas: índice de peróxidos (PV), cuantificación de tocoferoles y tocotrienoles, y periodos de inducción (IT) en Rancimat. La degradación de los aceites durante el proceso de fritura fue muy baja puesto que los niveles de compuestos polares y de antioxidantes naturales fueron similares a los encontrados en aceites refinados. La evolución de los índices analíticos durante el almacenamiento mostraron la importancia primordial del grado de insaturación del aceite por encima de la cantidad y tipo de antioxidantes y de la adición de AP. Sin embargo, la adición de AP a las patatas fritas tuvo un claro efecto sinergista traducido en menores PV y mayores cantidades de antioxidantes naturales e IT para cualquier tiempo de almacenamiento.

Oxidative stability of crisps fried in two vegetable oils: sunflower oil (SO) and partially hydrogenated sunflower oil (PHSO), was studied. Crisps were stored at temperature at daylight, at 40ºC in oven, and a -23ºC as a control. Evaluation of the samples was carried out by chemical and sensory analyses. Rancid odour and flavour were detected at 180 and 49 days of storage, at room temperature and 40ºC respectively. In parallel, Peroxide value (PV), polar compounds (PC) and TGox increased, while alpha tocopherol (AT) and the induction time (IT) decreased, confirming the low oxidative stability of the crisps fried in SO. On the contrary, crisps fried in PHSO, showed a good oxidative stability in both storage conditions until the end of the storage (210 days). Chemical analyses confirmed the high stability of crisps fried in PHSO and hence the influence of fatty acid composition in crisps shelf life. Statistical analysis showed a good correlation between PV, PC, TGox and AT. Finally, shelf life of crisps fried in SO was estimated from PV and it was found that one day of storage at 40ºC was equivalent at 4.9 days at room temperature., Se estudia la estabilidad oxidativa de patatas crisps elaboradas con dos aceites: girasol (AG), girasol parcialmente hidrogenado (AGPH). Las patatas se almacenan a temperatura ambiente con luz, a 40ºC en estufa de aire forzado, y a -23ºC, como control. La evaluación durante el almacenamiento se realiza mediante métodos químicos y sensoriales. El olor y sabor rancio del producto elaborado con AG, se manifestó a 180 y 49 días, a temperatura ambiente y 40ºC respectivamente, aumentando, en paralelo, el índice de peróxidos (IP), los compuestos polares (CP) y los triglicéridos oxidados (TGox), y disminuyendo la concentración de alfa tocoferol (AT) y el tiempo de inducción (TI), confirmando la inestabilidad del producto. Las patatas crisps elaboradas en AGPH se mostraron estables a temperatura ambiente y 40ºC. Los ensayos se detuvieron a los 210 días, sin detectarse olor y sabor a rancio. Los parámetros químicos confirmaron la estabilidad oxidativa del AGPH y la influencia de la composición en ácidos grasos en la vida útil del producto. Mediante análisis estadístico se demostró la existencia de coeficientes de correlación significativos entre IP, CP, TGox y AT. Finalmente, se estimó la vida útil de las patatas crisps elaboradas con AG, encontrándose que 1 día de almacenamiento a 40ºC equivalen a 4.9 días a temperatura ambiente.

[ES] En este estudio se aplican diferentes métodos analíticos -compuestos polares, distribución de compuestos polares, acidez, índice de peróxidos, dienos y tríenos conjugados, ácidos oxidados insolubles en éter de petróleo, viscosidad y ensayo oxifrit- a muestras de aceites de soja, girasol y mezclas de soja y colza, obtenidas en establecimientos públicos, antes y después de ser usadas en la fritura de patatas. Los dos objetivos principales fueron: conocer los compuestos formados durante el proceso de fritura de patatas y evaluar la posibilidad de sustitución de determinaciones complejas por métodos analíticos más simples y rápidos. Los resultados indicaron que, aunque los compuestos de polimerización y oxidación son los más representativos entre los nuevos compuestos originados durante el proceso, un 20% de las muestras contenían cantidades anormalmente elevadas de compuestos de hidrólisis cuya presencia es difícil de explicar. A partir de las correlaciones existentes entre métodos analíticos se puede deducir que, en este sector, la acidez libre y el porcentaje de dienos conjugados (o viscosidad), son útiles para predecir las cantidades de los principales grupos de nuevos compuestos presentes en los aceites de fritura poliinsaturados., [EN] In this study, different analytical methods, i.e. polar compounds, polar compound distribution, free fatty acids, peroxide value, conjugated dienes and trienes, oxidized fatty acids, viscosity and oxifrit-test, are applied to samples of both initial polyunsaturated oils and their counterparts after being used in the frying of potatoes in fast food shops. Two main objectives were established: the study of formation of new compounds during the frying process and the evaluation of possibilities to substitute complex methodologies for simpler and more rapid techniques. Results indicated that, although new compounds comming from oxidation and polymerization stand out, 20% of the samples contained ^jexsj high amounts of hydrolytic products i.e. diglycerides and fatty acids, whose formation is difficult to explain. From the analysis of correlation coefficients between analytical methods, the utility of free fatty acids and conjugated dienes (or viscosity) to predict the amount of the main groups of new compounds in used polyunsaturated frying oils, was deduced.