Effect of preservation techniques and food additives on staphylococcal thermonuclease

Staphylococcal TNase was found to retain its activity fully even after exposure to chilling and refrigeration temperatures for 24 h. It was not inhibited by p-hydroxy benzoic acid, sorbic acid, methylpropyl p-benzoic acid and sodium nitrite in the concentration range of 0.04 to 0.5%, whereas it was inhibited by 100 ppm of butylated hydroxy anisole (BHA), 200 ppm of butylated hydroxy toluene (BHT), and 300 ppm of propyl gallate. There was not complete inhibition of S. aureus and TNase by tocopherol (TP) and ascorbic acid (AA) even at concentration of 300 ppm. These results indicate that TNase can be used as an index of potentially enterotoxin producing S. aureus contamination in foods subjected to chilling, refrigeration as well as in foods containing common preservatives and antioxidants.     

A comparison of seed phosphatides and synthetic compounds as antioxidants for cow and buffalo ghee (butter fat)

The antioxidant capacity of seed phosphatides and synthetic antioxidants when compared in cow ghee was found to be in the order: phosphatidyl ethanolamine < propyl gallate <palmitoyl ascorbate <butylated hydroxy anisole < phosphatidyl choline. Phosphatidyl ethanolamine was found to be the most effective antioxidant. Cow ghee had less peroxide development than buffalo ghee. The ghee prepared at 100°C was more stable against peroxide development compared with that prepared at 50°C. These observations were supported by the analysis of ghee samples for peroxide values and for fatty acids. The phosphatides imparted more antilipolytic activity to ghee then to synthetic antioxidants.     

Simple Resolution of Butylated Hydroxyanisole and n-Propyl Gallate in Fatty Foods and Cosmetics Samples by Flow-Injection Solid-Phase Spectrophotometry

A biparameter sensor using flow injection with solid‐phase spectrophotometry for the simultaneous determination of butylated hydroxyanisole (BHA) and n‐propyl gallate (n‐PG) in fatty foods and cosmetics is proposed. The method is based on different transient retentions of these antioxidants when carried with methanol‐water 30:70%, vol/vol, through a flow cell packed to a 25‐mm height with C₁₈ silica. Each antioxidant was determined by measuring its intrinsic absorbance at its residence time (40 s at 272 nm for n‐PG; 200 s at 288 nm for BHA; calibration: 5.0 to 300.0 μg/mL; RSD: 1.7%) by flow technique and diode‐array detector. Resolution of the BHA‐n‐PG mixture in ratios between 1:10 and 10:1 is possible.     

Control of Lipid Oxidation in Cooked Ground Pork with Antioxidants and Dinitrosyl Ferrohemochrome

A number of antioxidants were added to ground meat prior to cooking to achieve oxidative stability. The 2-thiobarbituric acid (TBA) numbers of cooked-meat samples after storage for up to 35 days were determined. Of the antioxidants tested, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG), t-butylhydro-quinone (TBHQ), trihydroxybutyrophenone (THBP), nordihydro-guaiaretic acid (NDGA), catechol, and ethoxyquin were effective at a level of 200 ppm giving TBA values of less than one. BHA, TBHQ, and ethoxyquin were equally effective at a level of 30 ppm. Ascorbyl acetal and ascorbyl palmitate retarded lipid oxidation effectively (TBA values of slightly over one after five weeks of storage). The cooked cured-meat pigment showed some antioxidant effect which increased with increasing concentration, and at 18–24 ppm was better than that of 200 ppm of α-tocopherol.     

溶剂梯度结合流速梯度洗脱—高效液相色谱法快速测定食用植物油中四种抗氧化剂

该研究建立一种溶剂梯度结合流速梯度洗脱―高效液相色谱法快速测定叔丁基羟基茴香醚(BHA)、二丁基羟基对甲酚(BHT)、没食子酸丙酯(PG)、特丁基对苯二酚(TBHQ)四种抗氧化剂分析方法。试验以甲醇―0.5%乙酸溶液(v/v=65/35)为流动相进行梯度洗脱,并结合流速梯度洗脱,在10 min内分离上述四种物质。该法线性范围为0.25~250μg/mL,最小检测限为0.1~0.5μg/mL,线性相关系数为0.9995~0.9999,平均回收率为90.9%~96.1%,相对标准偏差(RSD)<5.0%(n=5)。该法灵敏度高、重现性好、操作方便、检测快速,可作为一种检测食品抗氧化剂有效方法。     

Presence of synthetic antioxidants in organic and conventional milk

Samples of conventional (n = 11) and organic (n = 81) milk, both raw and heat-treated, were analysed for the presence of synthetic antioxidants (butylated hydroxytoluene, butylated hydroxyanisole, dodecyl gallate, propyl gallate and octyl gallate) to verify whether those labelled as “organic” corresponded to EU Regulations on the use of additives in such products. The analysis detected only the antioxidant BHT and its aldehyde BHT–CHO in all 11 conventional milk and in 18 of 81 organic milk samples. The investigation highlights the importance of strict control of organic dairy production, since synthetic antioxidants added to feedstuff to prevent rancidity can be transferred to milk.     

Antioxidant properties of Mediterranean spices compared with common food additives

In this study, the antioxidant properties of Mediterranean food spices (annatto, cumin, oregano, sweet and hot paprika, rosemary, and saffron) at 5% concentration and of common food additives (butylated hydroxyanisole [BHA], butylated hydroxytoluene [BHT], and propyl gallate) at 100 microg/g are compared. The ability of these compounds to inhibit lipid peroxidation was, in decreasing order, rosemary > oregano > propyl gallate > annatto > BHA > sweet paprika > cumin > hot paprika > saffron > BHT. Deoxyribose damage is partially inhibited in the presence of cumin extract that exhibits the strongest protective action. The rest of the spices also protect deoxyribose better than the BHA and BHT used in the assay. Finally, the results obtained in the assay point to the prooxidant effect of propyl gallate. Hydrogen peroxide scavenging activity is measured by using peroxidase-based assay systems. In aqueous medium, the spice extracts show lower antioxidant activity than propyl gallate, the decreasing order being cumin > oregano > annatto > rosemary > hot paprika > sweet paprika. BHA and BHT did not scavenge H2O2 Spices are able to scavenge HOCl and protect alpha1-antiproteinase. The results indicate that rosemary and oregano are more effective HOCl scavengers than the other substances analyzed, which, in decreasing order, were propyl gallate, annatto, sweet and hot paprika, saffron, and cumin. The effect of Mediterranean food spices on the oxidative stability of refined olive oil tested by the Rancimat method was compared with common food additives during storage (72 h, 2, 4, and 6 months) at room temperature. The results showed that the spice extracts analyzed have significant stabilizing effects (P < 0.05).     

肉桂精油抗氧化性能及清除自由基能力的研究

对肉桂精油(CEO)的抗氧化和清除游离基活性的比较是基于总体抗氧化能力、清除超氧阴离子自由基能力、清除羟基自由基能力、抗亚油酸脂质过氧化能力、清除DPPH自由基5个方面,并与其他的合成抗氧化剂如BHT、PG做比较。实验结果表明,在一定浓度范围内,CEO的羟自由基清除能力强于BHT和PG;清除超氧阴离子自由基的能力强于PG;清除DPPH自由基能力、抗氧化活性比BHT和PG弱;CEO抑制亚油酸的过氧化能力比BHT和PG略弱。实验表明了CEO在某些方面具有良好的抗氧化效果。     

Migration analysis,antioxidant, and mechanical characterization of polypropylene-based active food packaging films loaded with BHA,BHT, and TBHQ

Polypropylene (PP) based active composite films were prepared by adding butylated hydroxy anisole (BHA), butylated hydroxytoluene (BHT), and tertiary butylated hydroquinone (TBHQ) antioxidants using the extrusion molding process. All concentrations of BHT, 2% to 3% BHA, and 3% TBHQ significantly increased the tensile strength (TS) of the composite films compared with control films. Increasing antioxidant concentration decreased TS values for BHT films, whereas an opposite trend was observed for BHA and TBHQ films. BHA at < 2%, BHT at > 2%, and TBHQ at all added concentrations significantly reduced elongation at break (E_b) of the composite films compared to control films. Water vapor permeability (WVP) of 1% BHT film was not significantly different from control. However, other antioxidants especially at increased concentrations significantly increased WVP values. TBHQ films with 300% to 662% increase had the highest WVP and BHT films with 5% to 81% increase had the lowest WVP among composite films. All three antioxidants had a negative effect on the transparency of the films; however the effect of BHA at higher concentrations was greater. The antioxidants did not change the color attributes of the films. Films containing all antioxidants showed 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, which increased with increase in their concentration, especially for those containing 3 wt.% BHT and TBHQ. Overall, incorporating BHA and BHT into a PP matrix improved mechanical, barrier, antioxidant properties, and film appearance and consequently were proposed for the development of antioxidant active PP films. TBHQ film is not recommended for food packaging because of its weak mechanical properties (lower E_b and TS values, higher WVP, and greater migration).     

Simultaneous determination of five antioxidants in food by HPLC with fluorescence detection

An HPLC method with fluorescence detection was developed for the determination of propyl gallate, nordihydroguaiaretic acid, butylated hydroxyanisole (2- and 3-tert-butyl-4-hydroxyanisole), tert-butylhydroquinone and octyl gallate in edible oils and foods. The antioxidants in edible oil were isolated directly with acetonitrile saturated with n-hexane. The antioxidants in food were extracted with ethyl acetate and the extract was concentrated under vacuum. They were isolated from the residue with acetonitrile saturated with n-hexane. The acetonitrile layer was centrifuged at 5,000 rpm for 10 min. The HPLC separation was performed on a Symmetry C18 column (3.5 microns, 4.6 mm i.d. x 150 mm) using a mixture of 5% acetic acid-acetonitrile-methanol (4:3:3, v/v/v) as the mobile phase and monitored by using a fluorescence detector with time programming. Sample peaks were identified by comparison of the fluorescence spectra with those of antioxidant standards. Average recoveries of fortified antioxidants at 100 micrograms/g were 72.1-99.6%. Coefficients of variation were 0.7-7.2%.     

DPPH antioxidant assay revisited

Scavenging of DPPH free radical is the basis of a common antioxidant assay. A number of protocols have been followed for this assay resulting in variation in the results of different laboratories. We present a perspective of the protocols followed by different workers with incongruity in their results and recommend a standard procedure within the sensitivity range of spectrophotometry. Three common standard antioxidants viz. ascorbic acid, BHT and propyl gallate have been used in this study. The IC₅₀ values for ascorbic acid and propyl gallate were 11.8 μM and 4.4 μM in methanol and 11.5 μM and 4.7 μM in buffered methanol as reaction medium, respectively. The free radical scavenging by BHT was markedly influenced by the reaction medium. The IC₅₀ values were 60.0 μM and 9.7 μM when the reaction was done in methanol and buffered methanol, respectively.     

EFFECT OF VARIOUS ANTIOXIDANTS ON THE OXIDATIVE STABILITY OF ACID AND ALKALI SOLUBILIZED MUSCLE PROTEIN ISOLATES

Protein isolates prepared from cod ( Gadus morhua ) myofibrillar proteins using acid or alkali solubilization are susceptible to oxidative rancidity. Oxidation could be delayed by the exogenous addition of antioxidants. The objective of this research was to compare the efficacy of antioxidants such as δ-tocopherol, butylated hydroxyanisole (BHA) and propyl gallate, to inhibit oxidation in acid- and alkali- solubilized cod protein isolates. Oxidation was catalyzed using cod hemolysate. Oxidation of lipids was monitored by the measurement of thiobarbituric acid reactive substances and painty odor. Results showed that protein isolates prepared using the acid process was significantly ( P <  0.05) more susceptible to lipid oxidation than alkali-solubilized protein isolates. Regardless of pH treatments, the efficacy of various antioxidants decreased in the order propyl gallate  >  BHA  >  δ-tocopherol.

PRACTICAL APPLICATIONS

Research has shown that seafood available for human consumption is rapidly getting depleted and that many fish species may become extinct in the next half-century or so. Acid and alkali solubilization methods are recent but well-known techniques used for preparing protein isolates from under-utilized aquatic species and the by-products of seafood industry. Although numerous researchers have studied the use of acid and alkali processes on several sources of seafood, almost no research has been done on the use of antioxidants to protect protein isolates from lipid oxidation. In our research, we have studied the effect of various antioxidants on the oxidative stability of acid- and alkali-solubilized fish myofibrillar proteins. The results from this work will enable the seafood industry to properly identify the process and the type of antioxidants required for making muscle food products with increased oxidative stability.     

Antioxidants in food and food antioxidants

Antioxidants may be present in foods as endogenous factors or may be added to preserve their lipid components from quality deterioration. Synthetic antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG) and tert-butylhydroquinone (TBHQ) are commonly used in food formulations. However, due to safety concerns, interest in natural antioxidants has intensified. To address the demand by consumers, mixed tocopherols, herbal extracts such as those of rosemary and sage, as well as tea extracts have been commercialized for food and nutraceutical applications. An overview of the topic is provided in this article.     

Antioxidant potential of synthetic and natural antioxidants and its effect on warmed-over-flavour in different species of meat

The role of natural antioxidants, e.g. Maillard reaction products (MRPs 60 mM/2 h), ascorbic acid (500 ppm), cloves (Eugenia caryophyllata) (250 mg/100 g), cinnamon (Cinnamomum zeylanicum) (250 mg/100 g) and synthetic antioxidants, e.g. tertiary butyl hydroxy quinone (TBHQ), butylated hydroxy anisole (BHA) and propyl gallate (PG), at 0.02% level each, in controlling the warmed-over-flavour (WOF), and non-haem iron release, as well as their potential in cooked and refrigerated stored meats from three common domestic species (sheep, beef and pork) has been investigated. MRPs and TBHQ showed good antioxidant activity (82–91%) and were significantly different (P < 0.05) from the other treatments in all three species. Significantly (P < 0.05) lower values of hexanal and non-haem iron were obtained for MRPs and TBHQ treated samples, which showed ability to control WOF during refrigerated storage. Non-linear correlation regression analysis was performed between non-haem iron, WOF values and antioxidant activity in all three species. Exponential fit equations were established for beef and pork, while for sheep, the relationship was found to be polynomial with correlation coefficients ranging from 0.90 to 0.97 for non-haem iron and WOF, respectively. The susceptibility of these species to lipid oxidation was in the order, pork > beef > sheep, and the order of antioxidant activity for the natural antioxidants was MRPs > cloves > ascorbic acid >  cinnamon; for synthetics it was TBHQ > BHA > PG.     

Storage Stability of Vacuum Packaged Frozen Pork Sausage Containing Soy Protein Concentrate, Carrageenan or Antioxidants

Fresh pork sausage patties containing carrageenan, without or with soy protein and an antioxidant were packaged with or without vacuum. They were evaluated for sensory properties, visual color, thiobarbituric acid reactive substances (TBARS), and Hunter color ‘L’, ‘a’, ‘b’ values at 4-wk intervals during 16 wk frozen storage. Rosemary extract was as effective as butylated hydroxytoluene (BHT)/propyl gallate (PG)/citric acid (CA) in antioxidant properties, but patties with BHT/PG/CA showed less surface discoloration (P < 0.05). In fat-control (FC) products, antioxidants combined with vacuum packaging provided optimum protection against rancidity. With vacuum packaging (VP), reduced-fat products maintained acceptable quality (TBARS and sensory properties) during 16 wks frozen storage.     

一类天然的功能性添加剂--抗氧化剂的开发和应用前景研究

目前国内使用的抗氧化剂主要是化学合成的 ,如丁基羟基茴香醚 (BHA)、二丁基羟基甲苯 (BHT)、没食子酸丙酯 (PG)、异抗坏血酸钠和乙氧基喹 (EQ)等 ,它们的抗氧化性能良好 ,广泛用于食品工业中。但化学合成抗氧化剂的安全性一直是十分敏感的问题 ,因此 ,来源于植物的天然食用抗氧化剂的开发和应用是中国食品工业的发展趋势 ,具有广阔的前景和市场潜力。本文介绍了几种具有发展前景的天然抗氧化剂的功能特性和用途     

Antioxidant effects of gallic acid alkyl esters of various chain lengths in oyster during frying process

The antioxidant effects of gallic acid (GA) and its alkyl esters including methyl gallate, ethyl gallate, propyl gallate, butyl gallate (GA-C4), octyl gallate, lauryl gallate, hexadecyl gallate and octadecyl gallate in frying oil (soybean oil) and oyster during frying were investigated. Rancimat induction period (RIP) assay indicated GA and its alkyl esters effectively improved the oxidative stability of soybean oil according to the ‘polar paradox’; that is, the antioxidant effects of the polyphenols decreased in lipid system with the increasing of hydrophobicity. Results also indicated that GA and its alkyl esters all effectively retarded lipid oxidation in oyster tissue according to parameters including RIP, peroxide value and electron spin resonance assays. Moreover, the antioxidant efficiency in oyster increased with the alkyl chain length until GA-C4, and thereafter, the antioxidant effects decreased, similar to the ‘cut-off effect’. This study provides basic data for improving the oxidative stability of seafood during frying.     

Inhibition of mackerel (Scomber scombrus) muscle lipoxygenase by green tea polyphenols

The high polyunsaturated fatty acid content of oily fish such as mackerel (Scomber scombrus) makes it particularly susceptible to oxidative degradation. We have shown previously the presence of lipoxygenase (LOX), a lipid oxygenase, in mackerel muscle. In the current study, commercially available green tea polyphenols were shown to effectively inhibit the LOX activity of mackerel muscle. EGCG (epigallocatechin gallate) was the strongest inhibitor tested with an IC₅₀ (concentration for half maximal inhibition) value of 0.13 nM. All the tea catechins showed a mixed non-competitive type inhibition. In addition, antioxidants such as BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene), esculetin, caffeic acid, ascorbic acid, and ethylene diamine tetraacetic acid (EDTA) were effective to varying degrees (IC₅₀ values between 0.02 and >50 μM) in the inhibition of mackerel muscle LOX. Nordihydroguaiaretic acid (NDGA), a classical LOX inhibitor and potassium cyanide (KCN), a heme protein inhibitor were assayed for their inhibitory activities for comparison.Post harvest spoilage of fish account for loss of as much as 10% of the world’s catches of cultured fish. This data indicates that the green tea polyphenols, nature’s very potent antioxidants, may be used as an effective and natural means of reducing post harvest spoilage in fish.     

Protective effect of gallic acid on the thermal oxidation of corn and soybean oils during high temperature heating

The comparative protective effects of gallic acid with well-known synthetic antioxidants (tert-butylhydroquinone, butylated hydroxylanisole, propylgallate) on the thermal oxidations of corn and soybean oils during heating for 8 h at 180°C were studied. The quantitative effects of gallic acid at three different concentrations on the time-course thermal oxidations in the two different vegetable oils were also studied for a prolonged heating of 6 days at 180°C. Gallic acid at 200 ppm exhibited higher protective activity than the synthetic antioxidants at the same concentration. Gallic acid also exhibited persistently strong protective activity, in a concentration dependent manner, on the changes in oxidation indices in corn and soybean oils throughout the prolonged heating period (6 days) at 180°C. The present results clearly suggested that gallic acid would be a potential natural substitute of synthetic antioxidants for the protection of vegetable oils during high temperature heating.     

几种抗氧化剂对亚麻油稳定性的影响

利用Schaal烘箱加速氧化实验,以酸价、过氧化值为指标,研究天然与合成抗氧化剂在不同复合配比条件下对亚麻油稳定性及货架期的影响,在100 ℃加速氧化条件下,选出0.04%迷迭香油＋0.018%叔丁基对甲氧酚＋0.018%没食子酸丙酯为本实验抗氧化剂的最佳配比。对比碱炼前后亚麻油酸价的变化,当向2 g亚麻油中添加NaOH的质量为0.30、0.35 g反应4 h后,酸价降低约80%,对延长亚麻油货架期的效果较为显著。根据Arrhenius经验公式,在60 ℃加速氧化条件下预测亚麻油在使用最佳抗氧化剂后货架期延长至352 d。