Effects of olive pomace and olive pomace oil on growth performance,fatty acid composition and cardio protective properties of gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax)

Gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) were fed with two experimental diets: olive pomace diet and olive pomace oil diet, in order to examine whether fish oil substitution in fish feeds by olive oil production wastes, such as olive pomace and olive pomace oil, has an influence on growth performance, fatty acid composition and cardio protective properties of fish. Gilthead sea bream fed with both experimental diets exhibited satisfactory growth performance factors while sea bass did not. The total lipids of gilthead sea bream fed with olive pomace diet contained statistically decreased levels of fatty acids, while exhibited the most potent biological activity against platelet aggregation induced by Platelet Activating Factor. These data indicate that olive pomace can be used as a partial substitute of fish oil in fish feed improving its cardio protective properties.     

Use of Supercritical Assisted Atomization to produce nanoparticles from olive pomace extract

Olive pomace is one of the most interesting wastes containing bioactive compounds; the extraction of polyphenols can represent an innovative solution for the reduction of the environmental hazard of this solid and the simultaneous recovery of high-added value compounds. In this study, Supercritical Assisted Atomization (SAA) was employed for the encapsulation in maltodextrin of phenolic compounds extracted from olive pomace. The effect of the ratio of maltodextrin content to total solid content of the extract and drying temperature on physical characteristics, total phenolic content and antioxidant properties of the powdered product were studied. The results confirmed the efficiency of the SAA process to encapsulate phenolic compounds from olive pomace extract. Particles with average diameter of 712 nm with high total polyphenol content (105.0 ± 0.1 mg_{Caffeic Acid Equivalent/}g_{Dry Powder}) and antiradical power (98.8 ± 3.0 mg_DPPH/mL_extract) were obtained. These particles rich in bioactive compounds can be used as functional component in formulations of new food, cosmetic or pharmaceutical products.Industrial relevanceOlive pomace is considered to be a low-cost and renewable source of high-added value compounds, such as polyphenols which can be valorized by several methodologies. In this work, we assessed the efficiency of Supercritical Assisted Atomization (SAA) in order to encapsulate phenolic compounds extracted from olive pomace. The particles obtained by SAA have spherical morphology with average diameter of 712 nm. The polyphenol-rich nanoparticles produced using this technique can be potentially used in the formulation of novel food or nutraceutical products.     

Preservation of salted,vacuum-packaged,refrigerated sea bream (Sparus aurata) fillets by irradiation: microbiological,chemical and sensory attributes

The effect of gamma irradiation (1 and 3 kGy) on the shelf-life of salted, vacuum-packaged sea bream (Sparus aurata) fillets stored under refrigeration was studied by monitoring the microbiological, chemical and organoleptic changes occurring in fish samples. Non-irradiated, salted, vacuum-packaged fish served as control samples. Irradiation affected populations of bacteria, namely, Pseudomonas spp., H₂S-producing bacteria, Brochothrix thermosphacta, Enterobacteriaceae and lactic acid bacteria. The effect was more pronounced at the higher dose (3 kGy) applied. Of the chemical indicators of spoilage, trimethylamine (TMA) values of non-irradiated, salted sea bream increased slowly to 8.87 mg N (100 g)⁻¹ flesh (whereas for irradiated, salted samples significantly lower values were obtained, reaching a final TMA value of 6.17 and 4.52 mg N (100 g)⁻¹ flesh at 1 and 3 kGy, respectively (day 42). Total volatile base nitrogen values increased slowly attaining a value of 60.52 mg N (100 g)⁻¹ for non-irradiated, salted sea bream during refrigerated storage whereas for irradiated fish, lower values of 48.13 and 37.21 mg N (100 g)⁻¹ muscle were recorded at 1 and 3 kGy, respectively (day 42). Thiobarbituric acid values for irradiated, salted sea bream samples were higher than respective non-irradiated (salted) fish, and increased slowly until day 28 of storage reaching final values of 1.01 (non-irradiated, salted), 2.15 (1 kGy) and 3.26 mg malonaldehyde kg⁻¹ flesh (3 kGy), respectively (day 42). Sensory evaluation (taste) showed a reasonably good correlation with bacterial populations. On the basis of sensorial evaluation, a shelf-life of 27–28 days was obtained for vacuum-packaged, salted sea bream irradiated at 1 or 3 kGy, compared to a shelf-life of 14–15 days for the non-irradiated, salted sample.     

Effect of dietary supplementation with olive pomaces on the performance and meat quality of growing rabbits

The aim was to investigate the effects of three types (A, B and C) of stoned and dehydrated olive pomaces (OPs), differing in olive cultivar, on productive performance and meat quality of growing rabbits. The inclusion of OPs (5%) negatively affected the performance of rabbits as it reduced the feed intake, growth rate, carcass weight and dressing out percentage (P < 0.05). Compared with the control, the meat of OP rabbits had a greater amount of monounsaturated and a lower amount of polyunsaturated fatty acids (P < 0.05), independent of the type of OP used. Oxidative processes in the meat of OPA and OPB were higher (P < 0.05), whereas OPC showed the same levels as the control group. This was due to the higher total polyphenol concentration and to the concomitant lower peroxide value of OPC. These results recommend the use of OP in rabbit diet with caution, taking into account the quality of the by-product in terms of oxidative status.     

Antibacterial and anti-PAF activity of lipid extracts from sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata)

The anti-PAF and the antibacterial activities of lipid extracts obtained from cultured sea bass (Dicentrarchus labrax) and cultured gilthead sea bream (Sparus aurata) were evaluated. Total lipids of sea bass and gilthead sea bream exerted PAF-like activity while, in higher amounts they inhibited this PAF activity. Neutral lipids of both sea bass and gilthead sea bream contained only PAF antagonists while the polar lipid fractions contained both PAF antagonists and agonists. Total lipids of sea bass exhibited stronger PAF-like activity than did those of gilthead sea bream; however, neutral lipids of sea bass contained stronger PAF antagonists than did gilthead sea bream.     

Combined densification and pulsed electric field treatment for selective polyphenols recovery from fermented grape pomace

The aim of this study is to assess a new process for the valorization of fermented grape pomace using pulsed electric fields (PEF). The combination of densification and PEF treatment was applied on grape pomace of low relative humidity, without any addition of conductive liquid. The kinetics of extraction and the composition of polyphenols were evaluated throughout the subsequent hydro-alcoholic extraction at different temperatures.Optimal parameters of PEF treatment (field strength E = 1.2 kV·cm^− 1; energy input W = 18 kJ·kg^− 1; density ρ = 1.0 g·cm^− 3) increased the content of total polyphenols regardless of the temperature of extraction. The ratio of total anthocyanins to total flavan-3-ols at 20 °C was equal to 7.1 and 9.0 for control and PEF treated modalities, respectively. These results demonstrate the selective nature of PEF treatment in anthocyanin extraction, and thus reveal new possibilities to produce extracts with different biochemical compositions.Industrial relevanceThis study examines the feasibility of densification combined with PEF pre-treatment of relatively low humidity grape pomace for the enhancement of bioactive compounds extraction. The concentration of total phenolic compounds obtained after PEF treatment showed that the use of this technique is relevant for an industrial use, since solvent amount and extraction time can be reduced. Moreover, the selective nature of PEF opens the opportunity to produce extracts of different biochemical compositions. This process is an alternative to conventional pre-treatments of raw material (e.g. dehydration and grinding), which have impacts on product quality and are more energy consuming.     

Effect of heating on the stability of grape and blueberry pomace procyanidins and total anthocyanins

Fruit by-products are rich sources of procyanidins and anthocyanins known for potential health benefits. Freeze dried blueberry pomace and grape pomace were heated in a forced air oven at 40, 60, 105, and 125 °C for 72, 48, 16, and 8 h respectively, to study the stability of procyanidins and total anthocyanins. Heating decreased procyanidin concentrations significantly (p < 0.05) in both blueberry and grape pomace, except when heated at 40 °C for 72 h. Reduction occurred when heated at 60 °C or above with no further reduction when heating temperature increased from 105 to 125 °C. Heating also affected total anthocyanin contents in both grape and blueberry pomace with no significant (p > 0.05) loss when heated at 40 °C. Total anthocyanin loss was highest at 125 °C for both blueberry (52%) and grape pomace (70%). Results suggested that while heating at lower temperatures for up to 3 days may not be detrimental, heating at higher temperatures for more than 8 h results in considerable loss of both the compounds.     

Lipid and protein oxidation of α-linolenic acid-enriched pork during refrigerated storage as influenced by diet supplementation with olive leaves (Olea europea L.) or α-tocopheryl acetate

The objective of this study was to evaluate the effect of diet supplementation with olive leaves or α-tocopheryl acetate on lipid and protein oxidation of raw and cooked n− 3 enriched-pork during refrigerated storage. Enrichment of pork with α-linolenic acid through diet supplementation with linseed oil enhanced (p ≤ 0.05) lipid oxidation in both raw and cooked chops but had no effect (p > 0.05) on protein oxidation during refrigerated storage while decreasing (p ≤ 0.05) the sensory attributes of cooked pork. Diet supplementation with olive leaves or α-tocopheryl acetate had no effect (p > 0.05) on the fatty acid composition of pork but decreased (p ≤ 0.05) lipid oxidation while exerting no effect (p > 0.05) on protein oxidation in both raw and cooked α-linolenic acid-enriched chops stored and chilled for 9 days. Moreover, olive leaves and α-tocopheryl acetate supplemented at 10 g/kg and 200 mg/kg diet, respectively, exerted (p ≤ 0.05) a beneficial effect on the sensory attributes of cooked α-linolenic acid-enriched pork chops.     

An improved rapid stigmastadiene test to detect addition of refined oil to extra virgin olive oil

Extra virgin olive oil is a premium food product that is likely to be the target of adulteration with refined olive oils or seed oils. Refining produces steroidal alkenes (sterenes) including stigmastadiene. This paper describes a rapid GC–MS method for the determination of stigmastadiene which is faster and more sensitive than the current official procedure based on GC-FID. The method does not require a saponification procedure for cold pressed oils, uses a stigmastadiene standard for quantification, has a low limit of quantification (0.015 mg kg^− 1) and gives excellent confirmation of peak identity at the current regulatory limit of 0.5 mg kg^− 1.     

Polar lipids,sphingomyelin and long-chain unsaturated fatty acids from the milk fat globule membrane are increased in milks produced by cows fed fresh pasture based diet during spring

Milk lipids are an interesting source of bioactive molecules with functional and nutritional properties. Although the composition of milk lipids is of utmost importance for food processing and human consumption, it is far from being fully known. The objective of this study was to perform a comparative analysis of the chemical composition of lipids from bovine milks produced in French Brittany during spring (fresh pasture based diet) and winter (corn silage based diet). The polar lipid content and relative proportions of the glycerophospholipids and sphingomyelin were determined using HPLC/ELSD. The fatty acid composition of total lipids and polar lipids was determined using GC. The milks collected in spring contained i) a lower amount of total lipids: 39.7 ± 0.8 g/kg vs 41.7 ± 0.5 g/kg in winter, ii) a higher amount of polar lipids: 138 ± 11 vs 112 ± 8 mg/kg milk; 3.5 ± 0.3 vs 2.7 ± 0.4 mg/g fat, which was related to a smaller size of fat globules, and iii) a higher amount of sphingomyelin, 32 mg/kg milk vs 25 mg/kg milk in winter. Interestingly, the polar lipids from the milk fat globule membrane contained a higher concentration of unsaturated fatty acids in spring (C18:1 n − 9, C18:2 n − 6, C18:3 n − 3 and long-chain n − 3 fatty acids). Milk from cows fed a fresh pasture-based diet during spring is an interesting source of dietary long chain polyunsaturated fatty acids for human consumption.     

A quantitative study on the phenolic compound,tocopherol and fatty acid contents of monovarietal virgin olive oils produced in the southeast region of Brazil

Consumption of virgin olive oil (VOO) is highly recommended due to its human health benefits. Brazil is now beginning to experimentally produce VOO, and there are no data on its chemical profile. The aim of this work was to determine the phenolic compound, tocopherol and fatty acid contents of 17 monovarietal VOOs produced from olive varieties cultivated in the southeast region of Brazil during two crop years. The chemical composition of Brazilian VOO resembles that found in the literature for well-established VOOs. The analyzed compounds comprised palmitic acid (6–12%), stearic acid (1.6–2.2%), oleic acid (70–84%), linoleic acid (3.2–11.7%), α-linolenic acid (0.6–1.4%), tyrosol (NQ–155 mg kg^− 1), (+)-pinoresinol (2.9–23 mg kg^− 1), hydroxytyrosol (ND–38 mg kg^− 1), luteolin (ND–2.2 mg kg^− 1), α-tocopherol (29–233 mg kg^− 1), β-tocopherol (ND–9.6 mg kg^− 1), and γ-tocopherol (ND—19 mg kg^− 1). There was a significant difference in the contents of almost all of the analyzed compounds between the two crop years. Principal component analysis demonstrated that some varieties can be differentiated from one another by chemical composition. The results indicated that some Brazilian monovarietal VOOs are promising and that further studies will help to improve the quality of Brazilian VOO.     

Routine and sensitive SPE-HPLC method for quantitative determination of pheophytin a and pyropheophytin a in olive oils

A sensitive and specific HPLC method with tandem diode array-fluorescence detection (DAD-FL) has been developed and validated for the simultaneous determination of pheophytin a (phy a) and pyropheophytin a (pyrophy a) in olive oils. Pigments were extracted with reverse phase solid phase extraction (RP-SPE) and subsequently analysed by HPLC-DAD-FL. The chromatographic analysis was carried out isocratically on ODS2 RP column using methanol–acetone (1:1 v/v) at flow-rate of 2.0 ml min⁻¹. Specificity of the method was assured by the simultaneous detection by UV–visible (410 nm) and FL (λ_Ex: 410 nm; λ_Em: 672 nm). Both compounds could be baseline separated within 7 min. The method was validated and applied in olive oil samples recently extracted as well as stored during 12 months. The limit of detection (LOD) defined at a signal-to-noise ratio of about 3 was ∼21.6 ng g⁻¹ for pyrophy a and ∼24.6 ng g⁻¹ for phy a under FL detection, and ∼148.0 ng g⁻¹ for both analytes under UV–visible detection. The calibration graphs were linear (r² > 0.9999; p < 0.01) between 0.25–14.00 ng μl⁻¹ for pyrophy a and 0.25–19.00 ng μl⁻¹ for phy a, under both fluorescence and UV–visible detection conditions. Recoveries of phy a and pyrophy a were over 94% as estimated by the standard addition method. Relative standard deviation for the intra-day and inter-day determination of phy a and pyrophy a were lower than 3.7% and 8.0%, respectively.     

Fish Meal or Cottonseed Meal as Supplemental Protein for Growing Holstein Steers

Twenty-three Holstein steers of 195 kg mean live weight were individually fed a complete mixed diet composed primarily of ground corn grain with either 140 g cottonseed meal or 90 g cottonseed meal plus 30 g menhaden fish meal/kg diet as the source of supplemental protein. Thirteen steers were slaughtered at 454 kg and 10 at 544 kg live weight. Steers slaughtered at 544 kg gained weight more slowly with consequent 18.2% increase in dry matter required per unit gain compared with steers slaughtered at 454 kg live weight. Steers fed the fish meal diet gained 1.34 kg/d and consumed 7.36 kg dry matter daily while steers fed the cottonseed meal diet gained 1.17 kg/d and consumed 7.40 kg dry matter daily. Dry matter consumed per unit gain was 12.6% less for steers fed fish meal diet than for steers fed cottonseed meal diet.     

Color,sensory and textural attributes of beef frankfurter,beef ham and meat-free sausage containing tomato pomace

The present investigation focuses on the textural properties, sensory attributes and color changes of beef frankfurter, beef ham and meat-free sausage produced by different levels of bleached tomato pomace. The texture and color profile were performed using an instrumental texture analyzer and colorimeter. The findings indicated that tomato pomace-added sausages had higher water holding capacity (WHC) compared to that of commercial samples. The frankfurters containing 5 and 7% (w/w) tomato pomace had the highest redness (a*), chroma (C*) and color differences (ΔE) values, while the meat-free sausages containing 7% (w/w) tomato pomace had significant (p < 0.05) values for lightness (L*) and yellowness (b*). Furthermore, there were no significant (p > 0.05) color differences between beef ham samples (with and without tomato pomace). A significant progression in the textural hardness and chewiness of systems containing tomato pomace was observed as well as higher sensory scores by panelists. According to sensorial evaluations, bleached tomato pomace improved the consumer acceptability and preference.     

Sensory evaluation of egg products and eggs laid from hens fed diets with different fatty acid composition and supplemented with antioxidants

Is the sensory quality of eggs influenced by adding vegetable lipids, animal and vegetable sources of n − 3 polyunsaturated fatty acids (n − 3 PUFA), and/or natural antioxidants to the hens diet? To answer this question three feeding experiments were conducted adding either palm butter, grape seed oil, flax seed oil, n − 3 PUFA such as flax seed and marine algae and the natural antioxidant rosemary to the hens diet. For each experiment a standard diet was used as control. The results suggested that vegetable lipids (palm butter, grape seed, flax seed), n − 3 PUFA (flax seed and marine algae) and rosemary may be used to hens fed diet without affecting the sensory properties of eggs.The sensory quality of eggs was evaluated on hard boiled, scrambled eggs and Madeira cake.In this work, we report the first sensory characterization of eggs and products containing eggs obtained from hens diet based on grape and algae plus vitamin E and rosemary extract.     

Effect of gutting on microbiological,chemical, and sensory properties of aquacultured sea bass (Dicentrarchus labrax) stored in ice

The effect of gutting on microbiological, chemical, and sensory properties of aqua-cultured sea bass (Dicentrarchus labrax) stored in ice was studied. Pseudomonads and H₂S-producing bacteria (including Shewanella putrefaciens) were the dominant bacteria at the end of the 16-day storage period in ice for both whole ungutted and gutted sea bass. Brochothrix thermosphacta and Enterobacteriaceae were also found in the spoilage microflora of ungutted and gutted sea bass but their counts were always less than those of Pseudomonads and H₂S-producing bacteria. Bacterial counts of whole ungutted sea bass were always higher than those obtained for gutted sea bass samples. Mesophilic counts for gutted and ungutted fish exceeded 7 log cfu g⁻¹ after 9 and 15 days of ice storage, respectively. Of the chemical indicators of spoilage, TMA values of ungutted sea bass increased very slowly whereas for gutted samples higher values were obtained reaching a final value of 0.73 and 4.39 mg N 100 g⁻¹, respectively (day 16). TVB-N values showed no significant increase for whole ungutted sea bass during storage reaching a value of 27.7 mg N 100 g⁻¹ (day 16) whereas for gutted fish 36.9 mg N 100 g⁻¹ was recorded. TBA values remained low for ungutted sea bass samples until day 16 of storage, whereas for gutted fish were variable. Of the chemical indices used, none proved useful means of monitoring early ungutted and gutted sea bass freshness in ice. Sensory assessment using the EC freshness scale gave a grade E for up to 5 days for the ungutted sea bass, a grade A for a further 2 days and a grade B for an additional 4 days, after which sea bass was graded as C (unfit). Gutted sea bass was given a grade E for up to 3 days, a grade A for the 4–7th days, and a grade B for the 8–10th days of storage, whereas on day 11 it was graded as unfit. Acceptability scores for odor, taste and texture of cooked ungutted and gutted sea bass decreased with time of storage. Results of this study indicate that the shelf-life of whole ungutted and gutted sea bass stored in ice as determined by the overall acceptability sensory scores and microbiological data is 13 and 8 days, respectively.     

Comparison of antiatherogenic properties of lipids obtained from wild and cultured sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata)

The aggregatory properties of lipid fractions, obtained from wild and cultured specimens of sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) were studied. The total lipids were extracted and separated into polar and neutral lipids. The polar lipids and neutral lipids were further separated by thin layer chromatography and the fractions obtained were tested for their ability to aggregate platelets or inhibit the platelet-activating factor (PAF)-induced aggregation. The aggregatory properties of the lipid fractions were dependent on the fish species and whether the fish samples were wild or cultured. The lipid fractions extracted from wild gilthead sea bream showed strong aggregatory properties, while the lipid fractions extracted from farmed fish showed strong inhibitory activities. The aggregatory properties of total lipids were mainly attributed to polar lipids while the PAF antagonistic activity was attributed to neutral lipids. The biological activities of such fractions with respect to their aggregatory properties may explain, in part, the protective role of fish consumption against cardiovascular diseases.     

Mathematical modeling on hot air drying of thin layer apple pomace

The hot air convective drying characteristics of thin layer apple pomace were evaluated in a laboratory scale dryer. The drying experiments were carried out at 75, 85, 95 and 105 °C and at the air velocity of 1.20 ± 0.03 m/s. Different mathematical models were tested with the drying behavior of apple pomace in the dryer. The results indicated that the Logarithmic model can present better predictions for the moisture transfer than others; the drying process took place in two falling rate periods, the effective diffusivities in the second period were about six times greater than that in the first period; the general relationship of moisture ratio against drying duration in the thin-layer convective drying of apple pomace were found and can be used in design and operation of the convective drying, suggested by 0.9923 of square correlation coefficient and 0.00001 of chi square.     

Mercury speciation in the muscle of two commercially important fish,hake (Merluccius merluccius) and striped mullet (Mullus barbatus) from the Mediterranean sea: estimated weekly intake

Total mercury and methylmercury concentrations were measured in the muscle tissue of two fish species from the Ionian and Adriatic seas. Higher total mercury and methylmercury concentrations were detected in striped mullet (Mullus barbatus), a benthic species (Ionian sea: Hg=0.40 μg g⁻¹ wet wt, MeHg=0.40 μg g⁻¹ wet wt; Adriatic sea: Hg=0.49 μg g⁻¹ wet wt, MeHg=0.44 μg g⁻¹ wet wt), than in hake (Merluccius merluccius), a pelagic species (Ionian sea: Hg=0.09 μg g⁻¹ wet wt, MeHg=0.09 μg g⁻¹ wet wt; Adriatic sea: Hg=0.18 μg g⁻¹ wet wt; MeHg=0.16 μg g⁻¹ wet wt). Total mercury residues were determined in all samples of both species from the Adriatic sea, while levels below the limit of detection were registered in 25% and 11%, respectively, of striped mullet and hake samples from the Ionian sea. In 18.8% and 22.2% of striped mullet samples from the Ionian and Adriatic seas, respectively, total mercury concentrations exceeded the maximum level fixed by the European Commission Decision (Hg=0.5 μg g⁻¹ wet wt). In the two different species, mercury was present almost completely in the methylated form with mean percentages between 60% and 100%. The estimated weekly intake for total mercury was below the established the provisional tolerable weekly intake (PTWI) for both species, though their consumption provides a methylmercury intake above the WHO safety limit.     

3-Chlorotyrosine formation in gilthead seabream (Sparus aurata) and European plaice (Pleuronectes platessa) fillets treated with sodium hypochlorite

The chlorination of tyrosine in fish fillets as a result of hypochlorite dipping was investigated and the formation of 3-chlorotyrosine was proved to be reproducible (average RSD < 6.0%). In European plaice, 0.85% (inner portion) and 1.88% (surface) of tyrosine were converted to 3-chlorotyrosine after 60 min dipping in 2000 mg/L NaOCl. As the dose of hypochlorite acid increased to 7816 mg/L, those percentages were 1.07% and 2.81%, respectively. Experiments on gilthead seabream showed the clear impact of dipping time and NaOCl concentration on the formation of 3-chlorotyrosine at the fillet surface and the levels of 3-chlorotyrosine reached a plateau at 1000 mg NaOCl/L. At the same dipping time, the 3-chlorotyrosine contents increased noticeably from about 1.40 to 4.90 ppm in gilthead seabream fillets treated with 125–1000 mg/L NaOCl. 3-chlorotyrosine formation was evaluated in four fish species (whiting, European plaice, gilthead seabream and Atlantic salmon) and proved to be species dependent, but no direct with the fat content could be found. During the chilled storage (4 °C), the 3-chlorotyrosine was constant. The use of 31 mg OClˉ/L could be detected for seabream.