Comparative Study and Quality Evaluation of Italian Focaccias Seasoned with Extra Virgin Olive Oil

An extra virgin olive oil was used as seasoning for three different types of focaccia produced on an industrial scale. This oil and samples of the oil extracted from the focaccias after baking were submitted to routine analyses and to silica gel column chromatography to separate polar compounds. These were then subjected to high performance size-exclusion chromatographic (HPSEC) analysis and it allowed to determine oxidative and hydrolytic degradation products. The results were compared with those obtained from artisan focaccias, seasoned with the same oil and toppings, by statistical analyses. The different technologies and the toppings employed directed in different ways the oxidative and hydrolytic processes in the oil.     

4种新疆地产芳香植物精油抗氧化作用比较研究

采用体外研究方法比较新疆地产玫瑰、迷迭香、椒样薄荷和罗马甘菊4 种芳香植物精油的抗氧化活性。测定4 种精油对1,1- 二苯基苦基苯肼(DPPH)自由基、羟自由基和超氧阴离子自由基的清除能力,同时用硫代巴比妥酸(TBA)法测定4 种挥发油对脂质过氧化反应的抑制作用。结果表明：4 种精油均可清除DPPH 自由基、羟自由基和超氧阴离子自由基,并可抑制卵黄不饱和脂肪酸过氧化,且清除各类自由基及抑制脂质过氧化作用与样品挥发油质量浓度正向相关。4 种精油抗氧化活性顺序为玫瑰＞迷迭香＞椒样薄荷＞罗马甘菊。     

橄榄油对再制奶油干酪品质的影响

以奶油干酪为基料,研究不同比例橄榄油替代黄油在再制奶油干酪中的应用。测定干酪的质构、色度、油脂析出性及感官评定,并进行比较分析。实验结果表明,25%替代水平的干酪在质地和色度方面都与对照组无显著性差异(P>0.05);在油脂析出性和感官评分方面,添加25%橄榄油的干酪均优于对照组。综上,2 5%替代水平的干酪样品与对照组在各项指标上相似度最高,是最合适的替代比例。     

辛癸酸甘油酯和橄榄油的极性调控研究

本文以添加了不同浓度表面活性剂司盘80(Sp80)的辛癸酸甘油酯(Octanoic acid glyceride,ODO)和橄榄油作为模型油脂,测定在不同剪切速率下ODO和橄榄油的表观黏度,分析不同司盘80添加量对ODO和橄榄油界面张力的影响,并对其抗聚并稳定性进行了评价,从而探讨不同浓度表面活性剂下油脂极性的变化规律。结果表明,ODO和橄榄油体系的表观黏度随司盘80添加量的增加而增大;当司盘80浓度小于5%时,ODO-水界面张力降低,ODO极性增大;而在橄榄油体系中,橄榄油-水的界面张力达到平衡所需司盘80用量较ODO少,当司盘80浓度大于1%时,橄榄油极性与界面张力无明显变化,且司盘80可增强ODO和橄榄油油滴的抗聚并稳定性;当司盘80浓度大于5%时,由于油相极性较大,油水间作用力增强且过量胶束生成,反而促进了橄榄油油滴的聚并。     

Nontargeted,Rapid Screening of Extra Virgin Olive Oil Products for Authenticity Using Near‐Infrared Spectroscopy in Combination with Conformity Index and Multivariate Statistical Analyses

A rapid tool for evaluating authenticity was developed and applied to the screening of extra virgin olive oil (EVOO) retail products by using Fourier‐transform near infrared (FT‐NIR) spectroscopy in combination with univariate and multivariate data analysis methods. Using disposable glass tubes, spectra for 62 reference EVOO, 10 edible oil adulterants, 20 blends consisting of EVOO spiked with adulterants, 88 retail EVOO products and other test samples were rapidly measured in the transmission mode without any sample preparation. The univariate conformity index (CI) and the multivariate supervised soft independent modeling of class analogy (SIMCA) classification tool were used to analyze the various olive oil products which were tested for authenticity against a library of reference EVOO. Better discrimination between the authentic EVOO and some commercial EVOO products was observed with SIMCA than with CI analysis. Approximately 61% of all EVOO commercial products were flagged by SIMCA analysis, suggesting that further analysis be performed to identify quality issues and/or potential adulterants. Due to its simplicity and speed, FT‐NIR spectroscopy in combination with multivariate data analysis can be used as a complementary tool to conventional official methods of analysis to rapidly flag EVOO products that may not belong to the class of authentic EVOO.     

橄榄油加工工艺及品质控制的探讨

研究了橄榄油加工新工艺 ,对橄榄油的质量控制进行了深入探讨 ,出油效率平均达84 7% ,产品质量完全达到国内和国际特级初制橄榄油标准 ,并具有良好的稳定性。该工艺技术成熟、可靠 ,有良好的推广应用价值     

Effect of Fat Level and Partial Replacement of Pork Backfat with Olive Oil on the Lipid Oxidation and Volatile Compounds of Greek Dry Fermented Sausages

ABSTRACT: High- and reduced-fat Greek fermented sausages were produced with 30% and 20% total fat in the initial formulation. The same products were manufactured with a partial replacement of pork backfat with 20% olive oil. The influence of the modification of the lipid fraction on the oxidation process was evaluated after 2 mo of storage. The reduction of fat increased thiobarbituric acid (TBA) values, total aldehydes, and typical lipid oxidation compounds (hexanal, 2-hexenal, 2-octenal). A significant decrease in oxidation was detected in batches containing olive oil, particularly in the sausages with the highest olive oil content. This addition decreased, in both fat level products, TBA values and hexanal, 2-hexenal, 2,4-hexadienal, benceneacetaldehyde, tt,2,4-nonadienal, and pentadecanal. The addition of olive oil significantly increased monounsaturated fatty acids content.     

A multivariate approach to optimise the synergistic blend of oleoresin rosemary (Rosmarinus officinalis L.) and ascorbyl palmitate added into sunflower oil

The simultaneous optimisation of a synergistic blend of oleoresin rosemary (ROS) and ascorbyl palmitate (AP) in sunflower oil (SO) was performed using central composite and rotatable design coupled with principal component analysis (PCA) and response surface methodology (RSM). The physicochemical parameters, viz. peroxide value, anisidine value, induction period, total polar matter, UV absorbances (232 and 270 nm) and antioxidant capacity were considered as response variables. PCA reduced the original set of correlated responses to few uncorrelated principal components (PC). The PC1 (eigenvalue, 6.08; data variance explained, 86.97%) was selected for optimisation using RSM. The quadratic model described the data (R² = 0. 93, P < 0.05), and lack of fit was insignificant (P > 0.05). The contour plot of PC 1 score indicated the optimal synergistic combination of 1309.62 and 129.29 ppm for ROS and AP, respectively. In conclusion, the versatility of PCA–RSM approach has resulted in an easy interpretation in multiple response optimisations.     

Oxidation on the Stability of Canola Oil Blended with Stinging Nettle Oil at Frying Temperature

The present study was carried out to investigate changes in fatty acids composition and their ratio by mixing of canola oil (CLO) with cold pressed stinging nettle oil (SNO) during heating at 180°C for 10 h, and analyzed by gas chromatography-mass spectrometry. The blended oils were prepared by gravimetrically mixing of CLO and SNO at various ratios of 60:40 and 40:60 w/w, respectively. Trans fatty acid in fresh CLO and SNO of 1.1 and 0.05%, whereas fresh blended oils of CLO:SNO (40:60, 60:40 w/w) contained 0.44, 0.91% and heated oils of CLO, SNO and CLO: SNO (40:60, 60:40 w/w) were found from 1.35 ?2.49, 0.06 ?0.09, and 0.46 ?0.51, 1.02 ?1.27%, correspondingly. The linolenic fatty acid is more prone to oxidation in heated oils and their percentage in fresh CLO, SNO and blended (40:60, 60:40) CLO:SNO samples of 10.58, 0.00, and 3.94, 6.64%, respectively. The linolenic acid was decreased from 10.27 ?6.54, 0.00, and 3.93 ?3.79%, 6.47 ?5.68% in heated CLO, SNO and CLO:SNO (40:60, 60:40 w/w) oils, respectively. The oxidation parameters were also analyzed such as free fatty acids, peroxide value, iodine value, conjugated diene and triene using standard methods. The best results of free fatty acids, peroxide value, iodine value, conjugated diene and triene were obtained in blended CLO:SNO (40:60 w/w) oil at 0.31%, 0.63 meqO₂/Kg, 0.79 g/100 g, 60 and 31.36% during 10 h. The obtained results show that mixing of CLO with SNO increased the stability against oxidation and consequently enhanced the worth of CLO during heating/frying route.     

Chlorophyllase Activity in Olive Fruits and its Relationship with the Loss of Chlorophyll Pigments in the Fruits and Oils

Chlorophyllase activity in fruit and chlorophyll pigment content in both fruits and their corresponding oils were studied in ripe olives of Arbequina and Picual varieties. It was demonstrated that the process of extraction of the virgin oil, as well as propitiating the pheophytinisation of chlorophylls initially present in the fresh fruit, also leads to marked losses of the chlorophyllic pigments. These losses were more acute in the Picual variety than in the Arbequina variety. Given that the levels of chlorophyllase activity measured in the fruits of the Arbequina variety were 100 times greater than those in the Picual variety, it is not possible to attribute the loss of chlorophyll pigments to activation of chlorophyllase during oil processing.     

杨梅籽油的脂肪酸组成及其氧化稳定性的研究

采用气相-质谱联用仪(GC-MS)分析了杨梅籽油的脂肪酸组成,以杨梅籽油的过氧化值为评价指标,考察了温度、光照、抗氧化剂、金属离子对杨梅籽油氧化稳定性的影响。结果表明:杨梅籽油中主要含有棕榈酸、硬脂酸、油酸、亚油酸、顺-13,16-二十二碳二烯酸等7种脂肪酸成分;在40℃以下的温度条件下,杨梅籽油具有良好的储藏稳定性,但随着储藏温度升高,杨梅籽油的氧化速度明显加快;自然光和日光灯照射对杨梅籽油的氧化反应均有明显的促进作用;抗氧化剂BHT、BHA、TBHQ和PG对杨梅籽油的氧化反应均有一定的抑制作用,其中TBHQ和PG效果比较明显;Fe2+、Cu2+等金属离子可以显著性加速杨梅籽油的氧化,Cu2+对杨梅籽油过氧化值的影响大于Fe2+。     

交变电场对储藏中毛油氧化及酚酸的影响

为探索交变电场处理对食用毛油氧化的影响规律以及潜在的内在因素,采用交变电场处理大豆和菜籽毛油,研究其储藏期间的主要酚酸含量变化及其与氧化特征的关系。结果表明,与对照相比,交变电场处理可显著抑制油脂POV升高,减缓氧化;在储藏期间电场处理 大豆和菜籽毛油的主要酚酸总量显著降低了20.1%和25.2%;大豆毛油中对羟基苯甲酸、丁香酸、香草醛和芥子酸显著降低了18.4%、6.5%、46.8%和21.4%,菜籽毛油分别降低了56.0%、42.5%、3.0%和23.6%。对照组大豆和菜籽毛油POV与各酚酸组分含量具有不同程度的正相关,而电场处理几乎相反,尤其是大豆毛油POV与芥子酸和香草醛含量呈显著负相关,菜籽毛油POV与芥子酸含量呈极显著负相关。交变电场处理促进了毛油中酚酸的消耗,延缓了油脂的氧化。本结果可为进一步研究电场对油脂氧化的影响机理和控制奠定理论基础。     

Effect of relative humidity and light conditions on the oxidative stability of sunflower oil blends stabilised with synthetic and natural antioxidants

The effect of relative humidity (RH) and light conditions on the oxidative stability of sunflower oil (SO) stabilised with oleoresin rosemary + ascorbyl palmitate (SOR), sage + ascorbyl palmitate (SOS) and tertiary butyl hydroquinone (SOT) was investigated. The SO without additive (SOC) served as positive control. Oil samples were subjected to 3 RH (29%, 52% and 75%) and two light conditions (dark, D and fluorescent light (600 lx), L) at 60 °C for 7 days. The oxidative stability was monitored by peroxide value (PV), conjugated diene value (CDV), free fatty acids (FFAs) and Rancimat induction period (IP). A direct relationship was noted between RH and increase in PV, CDV and FFA levels irrespective of light conditions. The detrimental effect of light on the oxidative stability was prominently noted at higher RH (75%) which followed an order: SOC > SOT > SOR > SOS. The samples stored under lower RH (29% and 52%), and dark conditions were better stabilised than light‐exposed counterparts.     

天然精油协同等离子体对盐水鸭杀菌保鲜及脂质氧化的调控

为调控等离子体处理对肉类造成的脂质氧化现象,研究复合精油协同低温等离子体（cold plasma,CP）处理对盐水鸭保鲜及脂质氧化的影响。采用牛至精油、肉桂精油和迷迭香配制复合精油,研究CP处理对复合精油抑菌性、总酚含量和1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除率的影响。此外,将复合精油协同CP处理盐水鸭,对18 d贮藏期内盐水鸭的菌落总数、大肠杆菌菌落数、色泽及脂质氧化进行测定。结果表明：CP处理未对复合精油的总酚含量和DPPH自由基清除率造成显著影响,但当复合精油质量分数为0.100%～0.125%且协同CP处理大肠杆菌菌液时,大肠杆菌菌落数可降低8（lg（CFU/mL））;同时,复合精油协同CP处理可使盐水鸭保质期显著延长,且对盐水鸭的色泽无显著影响,并能使样品硫代巴比妥酸反应物值从CP处理组的6.87 mg/kg降至4.58 mg/kg。     

Effect of oxygen reduction during malaxation on the quality of extra virgin olive oil (Cv. Carboncella) extracted through “two-phase” and “three-phase” centrifugal decanters

Quality and composition of virgin olive oil (VOO) are strictly dependent on complex processes that take place during the olive fruit crushing and malaxation of the olive paste. In this work, modulation of O₂ levels within malaxation chambers (R1: unmodified atmosphere; R2: oxygen: 12.73–4.64 kPa from the beginning to the end of malaxation; R3: 10.46–2.27 kPa; R4: 9.87–0.69 kPa) in two continuous “two-phase” and “three-phase” oil extraction plants was performed. Combined effects on the biosynthesis of nutritionally bioactive molecules and aroma volatiles and on the resulting sensory properties of the produced oils were investigated. Results showed that the type of oil extraction plant markedly affected the level of the phenolic compounds in the oil (and the related sensory attributes of bitter, pungency, astringency and bitter and pungency persistence). Reduction of O₂ concentration in the malaxing chamber, while having a minor impact on the presence of phenolic compounds, significantly affected the formation of all the examined volatiles. Particularly, lowered levels of oxygen hindered the formation of lipoxygenase derived volatiles weakening odours and flavours of artichoke, fresh fruity, and fresh cut grass.