Effect of storage conditions and antioxidants on the keeping quality of packaged oils

Journal of the American Oil Chemists' Society -     

Rheological characterization of yellow grease and poultry fat

The rheological properties of yellow grease and poultry fat and their liquid density at 25.0°C were experimentally determined. Dynamic viscosities of these industrial recycled fat products were measured for shear rates of 0.65 to 32.34 s⁻¹ at temperatures of 15.6 to 71.1°C. The resulting measurements were fitted to a power law model to obtain values for the consistency coefficient and the flow behavior index. The data was also fit to Andrade's equation to relate viscosity to temperature. These results indicated pseudoplastic flow behavior for both products, with increasing non-Newtonian behavior at higher temperatures and shear rates.     

复合肥产品质量控制的有效途径

分析复合肥生产过程中影响产品质量的主要因素,指出原料质量、原料配比、工艺控制、配方变化等影响产品的内在质量,造粒、烘干、包裹工序的操作影响产品的外观质量.同时利用质量管理统计技术,提出用控制图方法判断过程中出现的异常原因和偶然原因,通过过程能力指数(CP)及过程流通合格率等指标判断控制过程是否正常,并提出了相应的解决对策.     

The oven test as an index of keeping quality

The Schaal or Oven Test, originally developed by the biscuit and cracker industry to provide a relative rating for stability of various shortenings, has been generally adopted by shortening manulacturers. Advantages as well as limitations of the test are enumerated. It is possible to estimate the Oven Test by determining peroxide development in the test sample after two to four days in the oven. Oven Tests may also be conducted without having determined them organoleptically by observing the color change at the point of extreme rancidity. Peroxide formation occurring in a fat contained in biscuits or crackers when subjected to the Oven Test has been investigated and a simple and rapid method of extracting the fat, without changing its peroxide characteristics, has been devised. Lever brothers company     

Some notes on the keeping quality of fats in baked goods

Summary 1. Six fats have been tested for their stability in baked goods, both under normal and accelerated conditions. 2. Accelerated tests on the fats alone or on biscuits baked with them have not been found satisfactory for evaluating the stability of the fats. 3. The accelerated tests have been found particularly inadequate to properly evaluate the stability of hydrogenated lard in baked products. 4. It is concluded that the practice of evaluating fats for baking purposes by accelerated tests is not indicative of their true stability.     

几种防老剂对NR胶料耐老化性能的影响

试验研究几种防老剂对NR胶料硫化特性、耐热氧和耐天候老化性能的影响。结果表明,防老剂4010NA和YLD可以明显缩短NR胶料的t90,其它防老剂对NR胶料的硫化特性影响较小;加防老剂的NR硫化胶耐热氧老化性能明显提高,但各防老剂硫化胶之间的差异并不大;加防老剂8PPD,RE和YLD的NR硫化胶耐天候老化性能优异,加防老剂4010NA和4020的NR硫化胶次之,加防老剂RD的NR硫化胶较差。     

黄腐酸对农药杀虫脒的增效作用初探

黄腐酸可刺激作物生长,作者提出了腐植酸和杀虫剂的混合方法,作为一种新剂型,它比单用农药效果好,根据水稻试验结果,作者确信此混合剂和空白对照比较可增产17%。     

The effect of natural and synthetic antioxidants on the oxidative stability of palm diesel

Crude and distilled palm oil methyl esters conveniently known as palm diesel have been successfully evaluated as diesel substitute. Crude palm oil methyl esters are produced from transesterification of crude palm oil with minor components such as carotenes and vitamin E still intact and they are reddish in colour. The distilled palm oil methyl esters are obtained after the recovery of minor components (e.g. Carotenes and vitamin E) From the crude palm oil methyl esters. These valuable minor components are preferably to be recovered as they can be sold as value-added products before they are burnt together with the methyl esters as fuel. Although both possesses fuel characteristics which are comparable to those of petroleum diesel, crude palm oil methyl esters are found to exhibit better oxidative stability (rancimat induction period >25 h) than distilled palm oil methyl esters (about 3.5 h). It is attributed to the presence of vitamin E (about 600 ppm), a natural antioxidant in the former. While the distilled palm oil methyl esters contain practically no vitamin E (<50 ppm) and as a result, they exhibit poor oxidative stability. Thus, the crude palm oil methyl esters meet the european standard for biodiesel (EN 14214) which has set a minimum rancimat induction period of 6 h. In the present study, research was conducted to enhance the oxidative stability of distilled palm oil methyl esters in order to meet the aforementioned standard. Natural and synthetic antioxidants were used in the present study to investigate their effect on the oxidative stability of distilled palm oil methyl esters. It was found that both types of antioxidant showed beneficial effects in inhibiting the oxidation of distilled palm oil methyl esters. Comparatively, the synthetic antioxidants were found to be more effective than the natural antioxidants as lower dosage (17 times less) was needed to achieve the minimum rancimat induction period of 6 h.     

The effect of antioxidants in the autoxidation of methyl conjugatedcis,trans-octadecadienoates

The effect of antioxidants on the autoxidation of methyl conjugatedcis,trans-octadecadienoates was evaluated by estimating the induction period by measuring the increase in weight with time. Peroxide values and molecular weights were also used to determine extent of oxidation. UV and IR absorption were measured to determine conjugated dienes and isolatedtrans double bonds. Antioxidants, such as butylated hydroxy anisole (BHA), butylated hydroxy toluene (BHT), propyl gallate (PG) and sesamol, lengthened the induction period as much as seven to twelve times. After autoxidation to a weight gain of 10 mg per 1.5 g, the antioxidant containing samples had higher molecular weights and lower diene contents than the control samples. The induction periods were shorter, the peroxide values lower with or without antioxidants for the conjugated dienoates than for the nonconjugated dienoates. Effect of antioxidants might be explained by the formation of a hydrogen bond of the hydroxyl of the antioxidant and π-electrons as well as the inhibition of the chain-reaction.     

Effect of stabilization of crude whale oil with tertiary butylhydroquinone and other antioxidants upon keeping quality of resultant deodorized oil. A feasibility study

Journal of the American Oil Chemists' Society - Crude whale oil was stored under accelerated conditions for 146 days alone and in the presence of added antioxidants: 0.02% butylated...     

The effect of sensitizing dyes for photo as antioxidants on the autoxidation of methyl linoleate

The sensitizing dyes for photo which are cyanine homologues have been used as medicine and cosmetics. Their uses are widespread. The authors expected that these dyes might serve as antioxidants by a radical termination mechanism such as hydroperoxy radicals added to the many conjugated double bonds which exist in the dyes. Determination of the induction period by the weighing method confirmed that some sensitizing dyes for photo are available as antioxidants in the autoxidation of methyl linoleate. Therefore, these dyes may serve as new types of antioxidants.     

The effect of primary antioxidants and synergists on the activity of plant extracts in lard

The antioxidant activities of combinations of plant extracts and primary antioxidants or citric acid were studied in lard stored at 75°C. Methanol extracts of oregano, thyme, marjoram, dittany, rosemary and sage were used. When combined with butylated hydroxyanisole, butylated hydroxytoluene or ascorbyl palmitate the extracts showed an additive antioxidant effect, while combinations with propyl gallate did not increase the induction period obtained by the phenolic antioxidant. Negative synergism was observed when the plant extracts were mixed with DL-α-tocopherol. Citric acid showed a high synergistic efficiency with marjoram extract and a minor one with thyme extract, but it had a negative effect with all the others. Ternary mixtures of the plant extracts with citric acid and ascorbyl palmitate had lower activity than the corresponding dual combinations with ascorbyl palmitate, except for the mixture of marjoram extract.     

The kinetics of autoxidation of methyl linoleate. The effect of added antioxidants and a new method for the evaluation of antioxidants

A new method is described for the evaluation of antioxidants. Oxygen uptake by autoxidizing methyl linoleate both with and without antioxidants is measured in the Warburg apparatus and reaction orders, reaction rate constants, and length of induction periods determined. Tenox's BHT and BHA and Griffith's G-16 are evaluated and compared.     

The effect of antioxidants on butter in relation to storage temperature and duration

The effects of antioxidants on the oxidative stability of butter, under different storage time and temperature conditions, were evaluated. Natural (α‐tocopherol) and synthetic (BHA and BHT) antioxidants were added to the butter samples at two concentrations (50 and 100 ppm) immediately after the butter samples were produced from the pasteurised sweet cream, after which they were kept in the dark at 4 and ?20 °C for 6 months. Peroxide value (PV) and thiobarbituric acid (TBA) number and the residual antioxidants of the samples were examined at 30‐day intervals, starting on the second day until the end of the storage period. The measurements obtained by assaying PV and TBA number in butter samples showed that both the synthetic and natural antioxidants used were capable of protecting the butter samples against oxidation during storage at both temperatures. The butter samples with 50 ppm antioxidant could be stored for more than 180 days at 4 °C without spoilage. At ?20 °C, the addition of BHA, BHT and α‐tocopherol caused a reduction in the TBA number from 0.31 (control) to 0.21, 0.23 and 0.27 mg malonaldehyde/kg butter, respectively, and the PV decreased from 0.75 (control) to 0.46, 0.56 and 0.54 meq O₂/kg butter, respectively, after 6 months of storage. The highest residue values were determined in both the 100 and 50 ppm α‐tocopherol‐containing samples. These results indicate that α‐tocopherol exhibited a very strong antioxidant activity, which was almost equal to that of the synthetic antioxidants. Therefore, the use of α‐tocopherol is recommended as a natural antioxidant to suppress the development of rancidity in butter.     

Influence of grease formulation parameters on the tribological property of rice bran oil based lubricating grease

The negative environmental impacts and depletion of resources caused due to the excess usage of petroleum based products made researchers to think about an alternative biodegradable product. In the present study, rice bran oil (RBO) was used as a base oil for formulating 16 different grease samples. The thickener used was generated in situ by mixing 12-hydroxy stearic acid (12 HSA) to calcium hydroxide at a different ratio from 1.25 to 2. The formulation parameters such as weight % of thickener, saponification time, and maximum temperature spanned the ranges 5–11 wt.%, 1–2.5 h, and 150–180°C, respectively. The tribological properties such as wear scar diameter (WSD) and friction of 16 different grease samples formulated by varying these parameters were evaluated using a standard four-ball tester as per ASTM standards. The grease samples were characterized by evaluating the penetration value using a standard cone penetrometer. The influence of these formulation parameters on the experimentally evaluated properties was also examined in this work. The results indicated that the variation of these parameters during grease formulation has a significant influence on the evaluated properties.