Effect of long frozen storage on the formation of triglyceride alteration compounds of pan-fried functional restructured beef steaks

The influences of pan-frying in extra virgin olive oil (EVO) and frozen storage of functional restructured beef steaks on the contents of polar material (PM) and thermal oxidation compound of the fat extracted from them were determined. Two types of functional restructured meats: 20% walnut-added (W, 13% fat) and low fat (L, 2% fat) were studied in comparison to conventional medium fat (M, 13% fat) restructured beef steaks. Differences in the PM or the thermal oxidation and hydrolytic compounds were mainly due to meat formulation with fried L samples showing the highest PM and polymer concentrations and fried W steaks the lowest. After one year of frozen storage the PM content increased in all samples but markedly in L and W steaks. Polymers decreased in L and increased in W and M steaks. Thermal oxidation compounds increased in W and M steaks while hydrolysis increased markedly in L samples. Long-term storage of all fried steaks is not recommended, whether functional of not since lipid degradation occurs. Although these alterations after one year-frozen storage are still far from their discarding limit, the consumption of just cooked functional steaks is highly recommended.     

Effect of cooking on the chemical composition of low-salt, low-fat Wakame/olive oil added beef patties with special reference to fatty acid content

Changes in chemical composition, with special reference to fatty acids, as affected by cooking, were studied in low-salt (0.5%)/low-fat patties (10%) with added Wakame (3%) and partial or total replacement of pork backfat with olive oil-in-water emulsion. The addition of Wakame and olive oil-in-water emulsion improved (P < 0.05) the binding properties and the cooking retention values of moisture, fat, fatty acids and ash, which were close to 100%. Partial and total replacement of animal fat with olive oil-in-water emulsion reduced (P < 0.05) saturated fatty acids (SFAs), while total replacement also reduced (P < 0.05) polyunsaturated fatty acid (PUFAs) contents. The fatty acid concentration in cooked patties was affected by product formulation. Unlike the case of all animal fat patties, when olive oil was added the cooking process increased (P < 0.05) SFAs, monounsaturated fatty acids (MUFAs) and PUFA n-3 (linolenic acid) and n-6 (linoleic acid) contents. Cooked formulated patties with seaweed and partial or total replacement of pork backfat by oil-in-water emulsion and with seaweed added were less calorie-dense and had lower SFAs levels, while samples with olive oil had higher MUFAs levels.     

Effects of pan-frying in margarine and olive oil on the fatty acid composition of cod and salmon

Effects on the fatty acid composition of cod (Gadus morhua) and salmon fillets (Salmo salar) after pan-frying in margarine and olive oil were determined. The fatty acids of the margarine used were 55.5% saturated (SFA), 33.0% mono-unsaturated (MUFA) and 11.5% polyunsaturated (PUFA). The olive oil used contained 15.4% SFA, 76.1% MUFA and 8.5% PUFA. Using margarine or olive oil increased the SFA and MUFA percentages, respectively, in both species. For cod fillets (lean), pan-frying increased the fat content (0.55–4.15 g/100 g and 0.55–2.30 g/100 g before and after pan-frying, with margarine and olive oil, respectively), whereas, for salmon fillets (fat), it decreased (13.91 to 10.57 g/100 g and 15.35 to 12.95 g/100 g before and after pan-frying with margarine and olive oil, respectively). In conclusion, the culinary fat selection affects the total fatty acid content and composition of the prepared fish fillet.     

Evaluation of the quality of olive oil using fatty acid profiles by direct infusion electrospray ionization mass spectrometry

Electrospray ionization mass spectrometry is used to predict the olive oil quality according to European Union marketing standards. Samples were 1:50 diluted in an alkaline 85:15 (v/v) propanol/methanol mixture and directly infused into the electrospray ionization source of an ion trap mass spectrometer. The establishment of ratios of the peak abundances of the free fatty acids followed by linear discriminant analysis was employed to predict the olive oil quality grade. In addition, using multiple linear regression and partial least-squares regression, the percentages of extra virgin and virgin olive oils in binary mixtures were predicted with 5–11% average prediction errors.     

Fatty acid profile of olive oil extracted from irradiated and non-irradiated olive fruits

Syrian Kaissy cv olive fruit (SKOF) was irradiated (0, 1, 2, and 3 kGy). Oils were extracted from irradiated and un-irradiated olive fruits. Fatty acid profiles of Syrian Kaissy cv olive oil (SKOO) were measured by gas chromatography immediately after irradiation and after 6, 12, 24, and 36 months of storage. Results of the study showed that composition of fatty acids of SKOO were determined as palmitic (C16:0) (14.69%), palmitoleic acid (C16:1) (1.18%), stearic (C18:0) (2.19), oleic (C18:1) (68.94%), linoleic (C18:2) (12.22%), and linolenic acid (C18:3) (0.79%). The fatty acid composition of SKOO contains a healthy mixture of all the types of saturated mono-unsaturated and poly-unsaturated fatty acids. The data showed an increase (p < 0.05) in the percentage of the total saturated fatty acids and decrease (p < 0.05) in the percentage of the total unsaturated fatty acids of SKOO during storage. In general, there were no significant (p > 0.05) differences in fatty acids compositions of both oils extracted from irradiated and un-irradiated SKOF.     

Rats fed blended oils containing coconut oil with groundnut oil or olive oil showed an enhanced activity of hepatic antioxidant enzymes and a reduction in LDL oxidation

The effects of feeding Wistar rats with blended and interesterified oils of coconut (CO):groundnut (GNO) or CO:olive (OLO) on liver antioxidant enzyme activities and susceptibility of LDL to oxidation were studied. The hepatic lipid peroxidation (LPO) levels in the rats fed CO:GNO blend and interesterified oils were increased by 31% and 21%, when compared to the rats given CO. The superoxide dismutase activity was increased by 31% and 28%, and catalase (CAT) activity was increased by 37% and 39%, respectively, in rats given blends and interesterified oils of CO:GNO, as compared to those given CO. The activities of glutathione peroxidase (GPx) were increased by 17% and 20% in rats given CO:GNO blend and interesterified oils. Glutathione transferase (GST) level was also found to be increased by 26% and 31% after feeding blended and interesterified oils of CO:GNO, compared to those given CO. The LDL oxidation, which was elevated by feeding GNO, was found to be reduced by 10% and 14%, respectively, in the groups fed blended and interesterified oils of CO:GNO. Similarly, CO:OLO blended oils enhanced SOD, CAT, GPx and GST activities by 34%, 43%, 27% and 23%, respectively, compared to the rats given CO-containing diets. The corresponding increases in theses antioxidant enzyme activities when CO:OLO interesterified oils were fed to rats were 38%, 50%, 28% and 26%, respectively, when compared to rats given CO-containing diets. There was a significant reduction in hepatic LPO as well as oxidation of LDL, when blended and interesterified oils of CO:OLO were fed to rats. The results demonstrated that blended and interesterified oils of CO with GNO or OLO enhance hepatic antioxidant enzymes, decreased lipid peroxidation in liver and reduced the susceptibility of LDL to oxidation.     

Stability of avocado oil during heating: Comparative study to olive oil

The stability of the saponifiable and unsaponifiable fractions of avocado oil, under a drastic heating treatment, was studied and compared to that of olive oil. Avocado and olive oil were characterised and compared at time 0 h and after different times of heating process (180 °C). PUFA/SFA (0.61 at t = 0) and ω-6/ω-3 (14.05 at t = 0) were higher in avocado oil than in olive oil during the whole experiment. Avocado oil was richer than olive oil in total phytosterols at time 0 h (339.64; 228.27 mg/100 g) and at 9 h (270.44; 210.30 mg/100 g) of heating. TBARs was higher in olive oil after 3 h, reaching the maximum values in both oils at 6 h of heating treatment. Vitamin E was higher in olive oil (35.52 vs. 24.5 mg/100 g) and it disappeared earlier in avocado oil (at 4 vs. 5 h). The stability of avocado oil was similar to that of olive oil.     

Recovery and distribution of natural antioxidants (α-tocopherol,polyphenols and terpenic acids) after pan-frying of Mediterranean finfish in virgin olive oil

Samples of eight finfish representing the most popular fish species in Greece were pan-fried in virgin olive oil according to the Greek traditional culinary practice. Analyses for polyphenols, hydroxy pentacyclic triterpene acids (HPTA) and α-tocopherol were performed in the fresh and fried oils and fish. Polyphenols and HPTA were determined by GC/MS and α-tocopherol by HPLC. Nine polyphenols were determined in the frying oil samples; six of them were also found in fried fish. The terpenic acids oleanolic, maslinic and ursolic were also determined in frying oils and fried fish. No polyphenols and no HPTA were detectable in raw fish, while α-tocopherol was present in all samples. Besides water loss and oil absorption, pan frying caused the partial loss of all the antioxidants studied in the fried oils, as well as their enrichment in the fried fish. The overall retention of α-tocopherol in the fried oil and fish ranged from 30% to 80%, the respective values for polpyphenols and HPTA ranging between 51–87% and 46–88%. The polarity of the antioxidants studied, seems to affect to some extent their partition between the frying oil and the water-containing fish.     

Application of partial least square regression to differential scanning calorimetry data for fatty acid quantitation in olive oil

A chemometric approach based on partial least (PLS) square methodology was applied to unfolded differential scanning calorimetry data obtained by 63 samples of different vegetable oils (58 extra virgin olive oils, one olive and one pomace olive oil, three seed oils) to evaluate fatty acid composition (palmitic, stearic, oleic and linoleic acids, saturated (SFA), mono (MUFA) and polysaturated (PUFA) percentages, oleic/linoleic and unsaturated/saturated ratios).     

Effects of frying on polar material and free fatty acids in soybean oils

The purpose of this study was to investigate the quality deterioration of pressed soybean oil (PSBO), first grade solvent extracted soybean oil (FG‐SESBO) and third grade solvent extracted soybean oil (TG‐SESBO) with respect to time at 180 °C. It was found that there was a significant increase in total polar material (PM; P < 0.01) and free fatty acids (FFA; P < 0.05) in PSBO, FG‐SESBO and TG‐SESBO with increased time of frying. After forty‐five frying cycles, the final concentration of total PM was significantly higher in TG‐PSBO (30.39%) than in PSBO (21.10%) and FG‐SESBO (25.93%; P < 0.05). During frying cycles, the final acid value (AV) was significantly higher in PSBO (0.84 ± 0.02 mg KOH/g fat) than in TG‐SESBO (0.59 ± 0.01 mg KOH/g fat) and FG‐SESBO (0.56 ± 0.03 (mgKOH/g oil; P < 0.05). The content of saturated fatty acids in the three types of frying oils was significantly increased after forty‐five cycles of frying. However, even larger changes were observed in the content of unsaturated fatty acids, with decreases in C18:2, 9 c 12 c and C18:3, 9c 12c 15c and increase in C18:1, 9 c. The highest increasing slopes of PM and AV were observed in the TG‐SESBO.     

Looking through the qualities of a fluorimetric assay for the total phenol content estimation in virgin olive oil,olive fruit or leaf polar extract

As an alternate to the Folin-Ciocalteu assay (F-C) we propose a fluorimetric estimation of the total phenol content in virgin olive oil (VOO), olive fruit and leaf polar extracts. Phenol content was determined at excitation/emission wavelengths set at 280/320 nm. Standard operational procedures (slit widths, temperature, pH) and method validation were carried out according to Eurachem guidelines. The qualities of the proposed assay are better than those of the F-C one, as the procedure is more sensitive (LOD and LOQ values 10-fold lower), three times faster, needs no reagents and most importantly, is not destructive for the sample that can be further used in HPLC or other assays. Data for VOO extracts correlated well with the colorimetric ones (r = 0.69, n = 65). HPLC coupled with diode array and fluorescence detectors supported the above findings. Good correlations were also found between the respective data for olive fruit and leaf extracts (r = 0.96, n = 18).     

高含油量油菜种子和果皮油份积累及主要脂肪酸的动态变化

以高含油量油菜品系为材料,研究角果发育过程中种子和果皮油份积累与主要脂肪酸的动态变化。结果表明：高含油量品种在角果发育早期油份的合成与积累较为缓慢,开花后20d种子含油率仅占成熟种子油份含量的8．35％～12．32％,角果发育中期是油份含量增加最快的时期,开花后40d种子含油率占成熟种子油份含量的72．89％。94．73％,籽粒成熟时油份含量达到最大值。果皮的油份积累与种子相反,随角果发育油份含量依次下降,两者呈极显著负相关,相关系数为-0．95。种子和果皮的二十碳烯酸、芥酸合成规律明显不同。种子的7种主要脂肪酸组成中芥酸和二十碳烯酸与16碳、18碳脂肪酸含量均呈负相关,亚麻酸和亚油酸与棕榈酸、硬脂酸和亚油酸含量均呈正相关,与油酸含量H2和H27为正相关,H1和H28为负相关。而油酸与其它脂肪酸的相关关系较为复杂,与棕榈酸、硬脂酸和亚油酸、亚麻酸的相关关系有正相关,也有负相关,可见油酸的合成与积累不仅与棕榈酸、硬脂酸有关,还会影响亚油酸和亚麻酸的含量,这是创新油菜高油酸材料的基础。     

Prediction of the genetic variety of Spanish extra virgin olive oils using fatty acid and phenolic compound profiles established by direct infusion mass spectrometry

The genetic varieties of Spanish extra virgin olive oils (Arbequina, Hojiblanca and Picual) were predicted by direct infusion of the samples in the electrospray ionization source of a mass spectrometer, followed by linear discriminant analysis of the spectral data. The samples were 1:50 diluted (v/v) with an 85:15 propanol/methanol (v/v) mixture containing 40 mM KOH and infused. The abundances of the [M–H]⁻ peaks of the free fatty acids (7 peaks) and 28 phenolic compounds (20 peaks) were measured. Ratios of pairs of peak abundances were used as predictors in the construction of the linear discriminant analysis models. An excellent resolution between the three genetic varieties was achieved.     

Effect of dietary replacement of sunflower oil with linseed oil on intramuscular fatty acids of lamb meat

The effect of stepwise replacement of dietary sunflower oil (SO) with linseed oil (LO) on carcass composition, meat colour and fatty acid (FA) composition of intramuscular lipids of lamb meat was investigated. Thirty-six lambs were fed one of four diets consisting of pellets of lucerne with oil (60 g/kg): the diet varied in the composition of oil added and were: 100% SO; 66.6% SO plus 33.3% LO; 33.3% SO plus 66.6% LO and 100% LO. The experimental period was 7 weeks. Live slaughter weight, hot carcass weight and intermuscular fat percentage of chump and shoulder increased linearly with replacement of SO by LO.     

柠檬风味初榨橄榄油品质分析

以柠檬风味橄榄油为研究对象,通过其质量指标、脂肪酸组成、甾醇含量和香气组成综合分析柠檬风味初榨橄榄油的品质。结果表明：柠檬风味橄榄油油品酸值、过氧化值、紫外吸光度、脂肪酸乙酯含量、水分及挥发物均符合国家标准GB/T 23347-2021质量指标要求;新鲜柠檬的加入提高了脂肪酸含量,柠檬风味橄榄油中总脂肪酸含量比原味橄榄油高9.378 g/100g,柠檬风味橄榄油中亚油酸与亚麻酸比值7.75:1接近推荐值6.67:1,柠檬风味橄榄油不饱和度（5.37）高于原味橄榄油（5.03）;柠檬风味橄榄油中甾醇类化合物含量（1885.9mg/kg）低于原味橄榄油（2968.9mg/kg）;原味初榨橄榄油主要香气成分以醛类物质为主,柠檬风味初榨橄榄油主要香气成分是萜烯类物质,柠檬的加入使柠檬风味橄榄油特有β-蒎烯、α-松油烯、莰烯、(E)-β-罗勒烯、β-石竹烯、萜品油烯、α-水芹烯、桧烯8种萜烯类物质。柠檬风味橄榄油的品质与柠檬、油橄榄混合比例及其品种、成熟度、产地密切相关,避免柠檬的添加淹没初榨橄榄油的典型品质及香味从而获得理想的柠檬风味橄榄油,需重点优选柠檬和油橄榄混合比例因素。     

The effect of enriching milk‐based beverages with plant sterols or stanols on the fatty acid composition of the products

Five plant sterol (PS)‐enriched dairy products from the Spanish market were characterised for fatty acids (FA), volatile compounds and lipid stability. The ingredients used for PS enrichment by the food industry may come from different sources, thus influencing the composition and stability of the lipid fraction. In this study, the FA profile proved highly variable among samples, not agreeing with the nutritional labelling of the products. The volatile profile was characterised. A total of 55 volatile compounds were identified in the samples by GC–MS. Concentrations of hexanal (from 1.1 to 7.5 ng/g), nonanal (from 0.9 to 1.2 ng/g) and decane (from n.d. to 11.9 ng/g) indicated a low lipid oxidation extent. Peroxide value, ranking between 0.7 and 3.2 meq of active oxygen per kilogram of fat, except sample with fish oil, where peroxide value was 7.7 meq of active oxygen per kilogram of fat, and thiobarbituric acid reactive species, from 2 to 21 μg malondialdehyde (MDA)/g of fat, were in the lower limits of the ranges found in the literature.     

Effect of a high dose of CLA in finishing pig diets on fat deposition and fatty acid composition in intramuscular fat and other fat depots

Sixteen gilts were fed a control (4% of sunflower oil) or an experimental diet (4% conjugated linoleic acid (CLA) oil). CLA had no effect on intramuscular fat (IMF) content neither in longissimus thoracis (LT) nor in semimembranosus (SM) muscles but increased liver weight, reduced perirenal fat and tended to reduce backfat between the last 3th–4th lumbar vertebrae. Despite the fact that 9c,11t and 10t,12c CLA isomers were included in the same proportion in the diet, the 9c,11t and 9c,11c were the isomers more deposited in all tissues. Addition of CLA in the diet affected fatty acid composition in a tissue specific manner, increasing percentages of SFA in all tissues, reducing percentages of MUFA in LT and LT subcutaneous fat, and of PUFA in LT subcutaneous fat, liver and SM. The FA modification by dietary CLA in LT IMF was reflected in the different lipid fractions, SFA and MUFA mainly in the neutral lipid fraction, and PUFA in the polar fraction.     

核桃油中脂肪酸和内源抗氧化物质含量及其与氧化稳定性的相关性分析

以8个核桃品种为研究对象,有机溶剂萃取法提油,测定核桃油内源性组分（脂肪酸和内源抗氧化物质）和氧化稳定性（OSI）并对其进行相关性分析。结果表明：核桃油以不饱和脂肪酸（USFA）为主,其中以亚油酸含量最高,油酸/亚油酸比值（O/L）在0.3～0.5内;三种VE异构体按含量高低排序γ-VE>δ-VE>α-VE;甾醇含量由高到低排序为β-谷甾醇>菜油甾醇>豆甾醇;相关关系中,油酸和O/L与氧化稳定性呈极显著正相关（P<0.01,r1=0.7421,r2=0.8595）,亚油酸和多不饱和脂肪酸（PUFA）与氧化稳定性都呈极显著负相关（P<0.01,r1=-0.8457,r2=-0.9011）;核桃油氧化稳定性主要受脂肪酸影响（尤其是O/L）,其内源性抗氧化物质与油氧化稳定性并未呈现显著的相关关系。并且通过对比结果显示,新疆品种新巨丰榨取的核桃油氧化稳定性最高,相应O/L最低,适于长货架期的核桃油加工该结果将对核桃油氧化稳定性评价以及适宜制油核桃品种筛选提供一定的指导意义。     

亚麻籽油中脂肪酸成分的GC-MS分析

用无水乙醚提取亚麻籽油，经皂化、甲酯化处理，采用气相色谱-质谱（GC—MS）联用技术对其脂肪酸组成进行了分析和鉴定。共分离鉴定了13种脂肪酸：含有4种饱和脂肪酸，占脂肪酸总量的12．71％，其中以十六烷酸（7．31％）、十八烷酸（5．04％）为主；含有9种不饱和脂肪酸，占脂肪酸总量的87．1％，其中以亚麻酸（49．05％）、油酸（22．34％）、亚油酸（13．73％）为主。可见作为一种富含w-3和w-6不饱和脂肪酸的功能性油脂，亚麻籽油具有营养保健和药疗功效。     

Olive oil oxidation: Rejection points in terms of polar, conjugated diene, and carbonyl values

The changes in polar (POV), conjugated diene (CDV), and carbonyl (CV) values of a set of olive oil samples with a wide range of compositional parameters were monitored during 16 h heating at 180 °C. The POV, CDV, and CV linearly changed till the end of the heating process and increased on average from 6.8%, 7.0 mmol/l, and 11.7 μmol/g to 30.1%, 29.3 mmol/l, and 58.1 μmol/g, respectively. The CDV and CV of the olive oil samples were significantly correlated with the POV (R² > 0.98). The limits of 24% and 27% POV corresponded to 24.5 and 27.4 mmol/l CDV and 45.1 and 51.0 μmol/g CV, respectively.