Formation of the beef flavour precursors and their correlation with chemical parameters during the controlled thermal oxidation of tallow

Thermal oxidation of tallow was assayed by peroxide value (PV), p-anisidine value (p-AV), and acid value (AV), and the volatile compounds produced at different oxidation conditions were analysed by SPME-GC/MS. The accumulation of characteristic beef flavour precursors, such as hexanal, 1-octen-3-ol, (E,E)-2,4-decadienal and (E,E)-2,4-heptadienal, reached a maximum value when heated at 140 °C for 2 h with an air flow of 75 l/h per 100 g tallow, whereas at the same temperature PV and p-AV were both at high levels, and AV was relatively low. A correlation analysis of chemical parameters and volatile compounds showed that the beef flavour precursors were positively related to PV, and the off-flavour compounds were highly correlated to AV. Therefore, a moderate oxidation of tallow could be achieved via controlled thermal treatment.     

Effect of Extrusion on Lipid Oxidation

To examine extrusion temperature effects on oil stability, corn meal/ starch with soybean oil was extruded, frozen immediately in liquid nitrogen, freeze-dried and ground. The conjugable oxidation products (COP), oxodiene values (OV), peroxide values (PV) and conjugated dienes were determined during storage. There was an increase in COP, OV, PV, and conjugated dienes with an increase in extrusion temperature. An increase in transition metal content, particularly iron, occurred with an increase in extrusion temperature. Starch and soybean oil were extruded with 50 ppm ferrous acetate (dry weight) and 50 ppm butylated hydroxyanisole (BHA) (oil weight). Ferrous acetate reduced the oxidation relative to the control, which contained neither antioxidant nor iron, and relative to the sample containing BHA.     

Evaluation of the effectiveness of a new active packaging film containing natural antioxidants (from barley husks) that retard lipid damage in frozen Atlantic salmon (Salmo salar L.)

Salmon is a perishable fish that contains high level of PUFAs (polyunsaturated fatty acids), which have many positive effects on human health, but which are extremely susceptible to oxidation. The development of new food packaging films by incorporation of antioxidants is expected to improve the shelf life of food and thus increase consumer safety and health. Determination of peroxide value (PV), conjugated dienes (CD), conjugated triene hydroperoxides (TH), free fatty acids (FFA), totox value (TV), thiobarbituric acid index (TBARS) and p-anisidine value (AV) by established methods proved suitable for studying lipid hydrolysis and primary and secondary lipid oxidation in samples of salmon during frozen storage. The results obtained confirm the efficacy of natural antioxidants derived from barley husks (NABH) in slowing down lipid hydrolysis and increasing the oxidative stability of salmon flesh. This study demonstrates the potential usefulness of natural antioxidants extracted from barley husks in the development of active packaging films for food preservation.     

不同温度条件下鱼油氧化的动态变化

鱼油是水产饲料重要的脂肪源,但由于其富含多不饱和脂肪酸而极易氧化。系统研究了不同氧化温度下,鱼油过氧化值(POV)、酸值(AV)、碘值(IV)、羰基值(CV)和硫代巴比妥酸反应物(TBARS)随氧化时间的变化规律。结果表明:在各氧化温度下,鱼油的POV、AV、CV和TBARS均随氧化时间的延长而显著升高(P<0.05);IV随氧化时间的延长而显著降低(P<0.05)。在各氧化温度下,鱼油的POV和AV随氧化时间的延长均呈二次曲线变化;IV和CV随氧化时间的延长均呈线性变化;而TBARS随氧化时间的延长呈幂回归变化。     

Effect of cracklings hydrolysates on oxidative stability of pork meatballs fat

The aim of this work was to determine the effect of cracklings hydrolysates addition on the oxidative stability of fat and cholesterol in meatballs during 7 days of refrigerated storage.Changes in peroxide value (PV), anisidine value (AV), thiobarbituric acid reactive substances (TBARS) and cholesterol oxidation products (COPs) were determined. Cholesterol and oxysterols were analyzed as trimethylsilyl derivatives (TMS) by gas chromatography. Stability properties of antioxidants so employed were characterized by their inhibition activity.Analyzed enzymatic and acid hydrolysates of cracklings (EHC and AHC) obtained from meat industry by-product showed stability properties against fat and cholesterol. AHC exhibited a superior inhibition activity against fat oxidation than that of EHC because of smaller PV, AV and TBARS values. EHC showed a better inhibition activity against the formation of COPs in stored meatballs. After 7 days of storage, inhibition of formation of the oxysterols in samples with added hydrolysates was 29–54%. The antioxidative properties of EHC and AHC based on PV, AV and TBARS values were weaker than that of BHT. On the other hand, BHT was a poorer antioxidant than the hydrolysates against cholesterol oxidation in stored meatballs.     

加速氧化测试辣椒茎叶提取物对大豆油氧化稳定性的影响

食用油氧化稳定性是产品的一个重要指标,影响产品的安全性和货架期。采用加速氧化测定法,通过测定过氧化值(PV)、β-茴香胺值(p-AV)、共轭二烯烃(CD)和共轭三烯烃(CT)等指标研究辣椒茎叶提取物(PLSE)对大豆油氧化稳定性的影响。结果显示,在加速氧化测定条件下空白对照组大豆油4个指标逐渐增加,抗氧化剂BHT、BHA、TBHQ和提取物PLSE对大豆油氧化具有不同程度的抑制作用;10、100、200mg/kg剂量组PLSE对大豆油4个氧化指标的抑制作用均小于TBHQ(200 mg/kg),10、100、200 mg/kg剂量组PLSE对大豆油氧化指标PV和p-AV的抑制作用强于BHT(200 mg/kg)和BHA(200 mg/kg);而仅200 mg/kg剂量组PLSE对大豆油氧化指标CD和CT的抑制作用强于BHT和BHA。     

Performance of a lipase-catalyzed transesterified palm kernel olein and palm stearin blend in frying banana chips

The frying performance of an enzymatically transesterified palm stearin and palm kernel olein (1:1 by weight) blend was compared with its control (physical mixture or no enzyme added) and a commercial plastic frying shortening (CS). The samples were used as deep-fat frying media at 180°C for banana chips for seven consecutive days. The samples were then analysed for iodine value (IV), free fatty acid (FFA) content, peroxide value (PV), thiobarbituric acid (TBA) value, p-anisidine value (AV), total polar compounds (TPC), fatty acid composition, specific extinction, E^1%_1cm at 233 and 269 nm, polymer contents, viscosity and colour indices. The fried banana chips were analysed for acceptability by sensory evaluations. Storage properties of the banana chips were also evaluated by trained sensory panellists and a modified TBA test. The transesterified blend was found to have significantly (P<0.05) higher IV, FFA, PV, TBA value, AV, TPC, E^1%_1cm at 233 and 269 nm values, polymer content, viscosity and colour indices compared to the control, indicating that the transesterified blend was more susceptible to oxidative deterioration during deep-fat frying. CS generally showed the largest changes in most of the parameters, basically due to its high polyunsaturated fatty acid levels. There was no significant difference (P>0.05; for all the attributes tested) between the acceptability of the banana chips fried by the transesterified and control blends. However, the banana chips fried in CS had significantly (P<0.05) lower scores in terms of flavour, aftertaste and overall acceptability. This might be due to the typical hydrogenation flavour of CS. In the storage stability study of the banana chips, it was found that the banana chips fried in the transesterified blend were significantly (P<0.05) more rancid (lower score in sensory evaluations) and had a higher TBA value at the end of the storage time than the control.     

肉粉和肉骨粉氧化变质规律及抗氧化剂的抗氧化作用研究

以肉粉和肉骨粉为试验材料,分为空白对照组(不添加抗氧化剂)和分别添加0.1％、0.2％、0.3％和0.4％抗氧化剂的试验处理组(Ⅰ组、Ⅱ组、Ⅲ组和Ⅳ组);通过储存不同时间(1、10、20、30、60和90d),测定酸价(AV)、过氧化值(POV)、羰基值(CGV)和挥发性盐基氮(TVB-N),研究肉粉和肉骨粉随储存时间的氧化变质规律及不同水平抗氧化剂的抗氧化作用,并探讨各指标间的相关性.结果表明:随储存时间延长,肉粉和肉骨粉的AV和POV升高,而CGV和TVB-N则呈30 d之前先上升,随后下降的非线性趋势;不同水平抗氧化剂均能降低肉粉和肉骨粉中氧化产物含量,且以0.4％添加量抗氧化效果最好;肉粉和肉骨粉的AV与POV及CGV与TVB-N有极显著相关性(P＜0.01).     

Application of NMR to evaluate the oxidative deterioration of brown fish meal

Peroxide value (PV) and acid value (AV) are generally used as indices of deterioration in edible oil. However, they are not always useful for evaluation of oil deterioration in fish meal because the PV rises at the initial stage of oxidative deterioration, reaches a peak and then declines during long term storage of the meal; the AV hardly changes during long term storage. The use of NMR to evaluate oxidative deterioration of the oil in brown fish meal was examined. The ratio of olefinic protons to aliphatic protons (Ro) in brown fish meal oil determined by NMR decreased steadily with increasing storage time. By comparison with data from measurements of PV and AV, the Ro was considered to be useful as an index of oxidative deterioration in the oil in brown meal, especially in oil where the PV is peaking.     

Impact of supercritical carbon dioxide turmeric extract on the oxidative stability of perilla oil

The objective of this study was to determine the efficacy of supercritical carbon dioxide turmeric extract (STE) on the oxidative stability of perilla oil (PO), as measured by acid value (AV), peroxide value (PV) and oxidation induction time and compared to control and α-tocopherol containing PO as a positive control. The antioxidant activity was determined by DPPH, ABTS and FRAPS assays and individual bioactive compounds identified by chromatography. STE demonstrated significantly higher antioxidant activity than the α-tocopherol. The major components of the STE were identified as ar-turmerone, turmerone, curlone and bisabolene by GC-MS and curcumin and demethoxycurcumin by UPLC-Q-TOF MS. During thermal treatment at 65 °C for 24 h, the PO containing STE at different concentrations (100, 300, 500 and 1000 μg mL⁻¹) had significantly lower AV and PV, and at least 1.5 times higher induction period than those of the control and α-tocopherol-incorporated PO.     

Effect of refining on the lignan content and oxidative stability of oil pressed from roasted sesame seed

Oxidative stability of pressed and refined sesame oils during seven consecutive months of storage at room temperature was studied comparatively. Lignans, peroxide value (PV), p‐anisidine value (AV) and total oxidation value (TOTOX) were determined as evaluation indices. PV, AV and TOTOX of sunflower, corn and peanut oils were simultaneously monitored to compare their oxidative storage stabilities with the sesame oils. The total amount of lignans in the pressed and refined sesame oils were 1103 and 790 mg per 100 g respectively. The contents of sesamin and sesemolin in the pressed sesame oil were 734 and 369 mg per 100 g respectively. Sesamin and sesamolin content were reduced by 256 and 159 mg per 100 g, respectively, after refining. Nearly 40% of the sesamin epimerised to asarinin after oil refining. The results indicate that sesame oils pressed from roasted seed have far superior storage stability to oxidation than the other vegetable oils. This difference may be due to much higher sesamin and sesamolin contents in the pressed sesame oils. The results suggest lignan compositions and levels could be used as key indicators for evaluating the oxidative storage stability of sesame oil products as well as to differentiate between pressed and refined sesame oils.     

Tocopherol content,peroxide value and sensory attributes in roasted peanuts during storage

The objective of this study was to determine changes in tocopherol content, peroxide value (PV) and sensory attributes from roasted peanuts during storage at 40 °C. There were no differences in tocopherol contents between roasted and raw peanuts except in α‐tocopherol content that decreased after roasting. All tocopherol contents decreased during storage. On the contrary, lipid oxidation indicators such as PV and the intensity ratings of oxidised and cardboard flavour increased during storage. On the other hand, the intensity ratings of roasted peanutty flavour decreased with storage time. Good correlations were observed between tocopherol contents and PVs. Tocopherol contents could be used as indicator of oxidative state in peanut products.     

Effect of flavonoids on the oxidative stability of corn oil during deep frying

To study the effect of flavonoids on the stability of frying oil, refined corn oil was analysed periodically for its peroxide value (PV), p‐anisidine value (p‐AV) and iodine value (IV) after its use for deep‐frying of French fries at 180 °C for varying periods of time, namely 30, 60 and 90 min. PV and p‐AV values increased with respect to time while a decrease in IV was observed with increase in time (P < 0.001). Deep‐frying of French fries in corn oil was then carried out in the presence of flavonoids, viz. pelargonidin, cyanidin, quercetin, myrecetin and gallic acid as antioxidants. All antioxidants effectively reduced the oxidation rate in the oil, as detected by decrease in PVs and p‐AVs and relatively low reduction rate in IVs (P < 0.001). The order of antioxidative activity was gallic acid > quercetin > myrecetin > cyanidin > pelargonidin.     

Empirical models to correlate the basic physical and chemical indices of modified rice bran and mustard oil

Modified rice bran oil (RBO) and modified mustard oil (MO) were prepared by adding oleic acid and oxidized oil separately. The physical and chemical indices like dielectric constant, viscosity, peroxide value (PV), acid value (AV), free fatty acids (FFA), iodine value (IV), and saponification value (SV) of pure and modified RO and MO were determined and correlated. Dielectric constant and viscosity were found to decrease in a non-linear fashion with increase in temperature (30°C–75°C). The dependence of dielectric constant and viscosity with temperature was investigated using model empirical equations. The dielectric variation was studied using Akerlof and Oshry’s model equations, which exhibited high dependency of R² ranges from 0.99 to 0.997. The behaviour of viscosity with temperature was studied with Wright’s equation and the correlation coefficient (R²) was found to be 0.998. Model equations were developed, which relates dielectric constant with IV, SV, and PV with the regression coefficients R² = 0.955, 0.936, and 0.994, respectively. The developed equations can be used in processing, pipelining, and to predict the parameters at a desired temperature. On comparing the correlations between the physical and chemical properties of the oil samples, RBO and its modified forms exhibited more oxidative stability than modified MO.     

Oxidative Stability of ω3-rich Camelina Oil and Camelina Oil-based Spread Compared with Plant and Fish Oils and Sunflower Spread

ABSTRACT: The oxidative stability of ω3‐rich oil from Camelina sativa and the storage stability of a camelina oil‐based spread were evaluated. Camelina oil was more stable than fish oil and linseed oil, but less stable than sunflower, corn, sesame, and olive oils, indicated by measuring peroxide values (PV), ρ‐anisidine values (AV), total oxidation values (Totox), thiobarbituric acid reactive substances (TBARS), conjugated diene levels (CD), and conjugated triene levels (CT) during storage at 65 °C for 16 d. The camelina oil‐based spread had higher PV, AV, Totox, TBARS, CD, and CT than the sunflower spread but maintained adequate sensory quality for 16 wk of storage at 4 °C or 8 °C.     

低盐低硝腊肉复合抗氧化剂最佳配方的研究

防止、减缓脂肪的氧化是低盐、低硝腊肉急需解决的问题之一,本试验在腊肉制作中添加天然、高效、安全的茶多酚、异抗坏血酸钠、迷迭香作为其抗氧化剂,三种抗氧化剂在腊肉中协同抗氧化,通过测定腊肉酸价、过氧化值以及腊肉色泽的变化,得到抗氧化剂最佳组合为:茶多酚0.3g/kg、异抗坏血酸钠0.3g/kg、迷迭香抗氧化剂0.1g/kg。抗氧化剂以此最佳配比制作腊肉,保质期内酸价及过氧化值均显著低于国家限定标准。     

不同脂肪酸组成的食用油热氧化稳定性研究

为研究高温加热对不同脂肪酸组成的食用油氧化稳定性的影响,用170℃高温连续三天分别加热富含饱和脂肪酸的棕榈油、富含多不饱和脂肪酸的花生油以及富含单不饱和脂肪酸的山茶油,检测其酸价、碘值、过氧化值、p-茴香胺值、全氧化值、维生素E含量及脂肪酸组成的变化。结果表明:经过加热处理的三种食用油与未加热处理的相比,7个指标均存在显著性差异（p<0.05）。加热过程中,山茶油的过氧化值增加量最大,且加热对花生油的酸价、碘值、p-茴香胺值、全氧化值影响最大;维生素E含量急剧降低;脂肪酸组成的变化明显,反式脂肪酸的增加量最高,高达1.53%。三种食用油的热氧化稳定性依次为:山茶油>棕榈油>花生油;食用油氧化稳定性可能主要由其脂肪酸的组成（COX值）决定,当COX值相近时维生素E含量影响其氧化稳定性。      

以形成特征性羊肉香味为目标的热反应工艺研究

通过正交试验、单因素逐步优化试验对影响热反应产物风味的主要因素氧化羊脂、甘氨酸、VB1、木糖、丙氨酸、热反应温度等进行调控,确定了添加羊脂控制氧化产物以形成羊肉特征香味的较佳热反应工艺:葡萄糖0.96g、木糖0.30g、甘氨酸0.40g、丙氨酸0.30g、L-半胱氨酸2.86g、植物蛋白水解酶(HVP)液2.40g、磷酸盐缓冲液3.80g、VB10.90g、氧化羊脂0.23g(过氧化值187.3mmol/kg脂肪、茴香胺值238.1、酸值2.8mgKOH/kg脂肪);pH6.0,温度110℃,加热时间40min。     

Thermooxidative Stability of Fennel Oleoresin Microencapsulated in Blended Biopolymer Agents

In this work, the oxidative and thermal stabilities of 4 different encapsulating agents (chitosan [CH], modified starch [MS], gum arabic [GA], and maltodextrin [MD]) used in fennel oleoresin microencapsulation by the freeze‐drying technique were evaluated both individually and in blends (binary and ternary ones). The oxidative stability of the encapsulated products was assessed by gas chromatography/mass spectrometry analysis of the secondary oxidation volatiles along with the use of oxidation markers (peroxide value, PV), while a differential scanning calorimetery analysis was conducted. Gum arabic, both plain and its mixtures, exhibited the lowest protection against lipid oxidation, presenting high PVs. However, good microencapsulation efficiency along with the best oxidative stability in terms of PV and thermal stability indicated that the formulations of MS‐CH and MS‐MD‐CH could be suggested as alternative encapsulating agents.