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.     

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.     

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 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.     

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 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 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.     

Study on the effect of antioxidants in the autoxidation of methyl nonconjugated octadecadienoates

Many studies have been published on the effect of antioxidants on unsaturated fatty acid esters but the differences of the effects of antioxidants on geometric isomers have never been investigated. In this study, methylcis-9,cis-12-octadecadienoate and itstrans isomer methyltrans-9,trans-12-octadecadienoate were used as methyl nonconjugated dienoates, and BHA, BHT, PG, NDGA, 4,4′-dihydroxy-3,5,3′,5′-tetratert-butyl diphenyl methane, L-thyroxine sodium salt,a-tocopherol and sesamol were used, as antioxidants. The differences of the effects of antioxidants on both geometric isomers were investigated by determining the induction period using the weighing method. Also determined were the infrared and ultraviolet spectra, peroxide values, conjugated diene contents, isolatedtrans double bond contents and molecular weights for the controls and the samples containing antioxidants. Thecis,cis isomer was more easily autoxidized and had a shorter induction period than thetrans,trans form. By the end of the induction period, no isolatedtrans double bond forms in thecis,cis isomer, but a considerable amount of isolatedtrans double bond decreased in thetrans,trans isomer. In general, the effects of antioxidants, except NDGA, on thecis,cis isomer were larger than thetrans,trans form.     

浅谈氧化镁对水泥熟料质量的影响

水泥生产过程中，原材料化学成分的稳定性对整个生产工艺和熟料质量的稳定性起着重要的作用。石灰石的比例在生料配料中约占80％左右，所以石灰石化学成分的稳定性对生料成分及煅烧工艺的影响尤其显著，特别是MgO含量的波动更是如此。本文通过高镁石灰石在STH水泥厂的应用实践。从MgO含量对熟料质量及煅烧工艺的影响等方面，谈谈自己的一点体会，以供同行参考。     

A simple method for the improvement of the keeping quality of oils and fats

Summary The efficiency of antioxidants is judged by means of a modified Swift test. Addition of 0.05% sulfur during the deodorizing process yields a 4-1.4 time prolonged keeping time of oils and fats. There is a linear relation between iodine value and the remaining speed of oxidation in % in the tests made with sulfur. The reduction of the velocity is inversely proportional to the iodine value. The effects of gallate and the sulfur seem to be additive. The residual amount of sulfur left in the oils and fats after deodorization is very small and only slightly higher than that present in ordinary deodorized oils and fats.