Elaboration of enriched margarine with lentisk oil and honey: Formulation,characterization, and monitoring of oxidative stability

This study focused on the use of lentisk oil and honey as natural sources to formulate margarine with ameliorated quality and oxidative stability. For this, five margarines were formulated with honey and different concentrations of lentisk oil. Analyses were performed on oil and honey used, and then physicochemical characterization and several oxidative stability tests were applied to assess margarine quality. The results showed a significant richness of lentisk oil and honey in total phenolics and total flavonoids and expressed good antioxidant activities. As well as the evaluation of oxidative stability of enriched margarines during 3 months of storage demonstrated that margarine added with 2% lentisk oil (M1) had the best resistance properties and longer Rancimat induction time (22.26 h), better than the control and margarines added with 5% (M2), 10% (M3), and 15% (M4) lentisk oil. Globally, margarines prepared with high concentrations of lentisk oil (M2–M4) were not different from the control, whereas only M1 was permitted to ameliorate the stability of margarine with a slight influence on physicochemical parameters. The elaboration of margarine supplemented with 2% lentisk oil improves the properties of the product, which could then be applied to margarine manufacturing.     

Autoxidation of synthetic isomers of triacylglycerol containing eicosapentaenoic acid

Several triacylglycerols (TAG) that contained eicosapentaenoic acid (EPA) were chemically synthesized and stored at 25°C to assess the influence of TAG structure on oxidative stability and formation of oxidation products. Oxidative stability was evaluated by oxygen consumption during storage of the TAG. Autoxidation products of TAG were analyzed by high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). Results showed that a 2:1 (mole/mole) mixture of trieicosapentaenoylglycerol (EEE) and tripalmitoylglycerol (PPP) was most susceptible to autoxidation. The oxidative stability of TAG that contained EPA and palmitic acid was negatively correlated with the moles of EPA in a single TAG molecule. When TAG with one EPA and two other fatty acids were oxidized, chainlength of constituent fatty acids hardly affected the oxidative stability of EPA-containing TAG molecules, except for stearic acid. HPLC and LC-MS analyses showed that monohydroperoxides were major oxidation products regardless of type of TAG. Bis- and tris-hydroperoxides were formed during autoxidation of EEE and dieicos-apentaenoylpalmitoylglycerol. Monohydroperoxy epidioxides were found in all autoxidized TAG. These observations suggested that TAG structure affected the oxidation of TAG with highly unsaturated fatty acids.     

Oxidative stability of soybean oil products obtained by regioselective chemical interesterification

Oxidative stability of products produced as potential margarine basestock from soybean oil and methyl stearate by a novel chemical regioselective interesterification was evaluated. The oxidative stability of the products was evaluated by peroxide formation and volatile analysis during storage in the dark with oxygen at 60°C for 72 h. The product obtained by regioselective interesterification resulted in the lowest peroxide formation and volatile concentration sample in comparison with soybean oil and the randomized product of the regioselective interesterified product. Regioselective interesterification of soybean oil with methyl stearate produced a product with increased oxidative stability. Presented at 84th American Oil Chemists’ Society Annual Meeting, April 26–30, 1993, Anaheim, California.     

Oxidative stability of soybean oil fatty acid methyl esters by oil stability index (OSI)

Biodiesel, an alternative diesel fuel derived from transesterification of vegetable oils or animal fats, is composed of saturated and unsaturated long-chain FA alkyl esters. During long-term storage, oxidation caused by contact with air (autoxidation) presents a legitimate concern with respect to monitoring and maintaining fuel quality. Extensive oxidative degradation may compromise quality by adversely affecting kinematic viscosity, acid value, or PV. This work examines the oil stability index (OSI) as a parameter for monitoring the oxidative stability of soybean oil FAME (SME). SME samples from five separate sources and with varying storage and handling histories were analyzed for OSI at 60°C using an oxidative stability instrument. Results showed that OSI may be used to measure relative oxidative stability of SME samples as well as to differentiate between samples from different producers. Although addition of α-tocopherol or TBHQ increased OSI, responses to these antioxidants varied with respect to SME sample. Variations in response to added antioxidant were attributed to aging and other effects that may have caused oxidative degradation in samples prior to acquisition for this study. Results showed that OSI was more sensitive than iodine value in detecting the effects of oxidative degradation in its early stages when monitoring SME during storage.     

亚硫酸盐失效原因及防止方法的研究

通过模拟贮存试验,研究了亚硫酸盐失效原因及防止方法。结果表明,目前广泛应用的亚硫酸盐法防止氧腐蚀效果有时不佳的原因主要是亚硫酸盐溶液在贮存期间的自动氧化。水质和ｐＨ值等条件对自动氧化几乎没有影响,自由基引发剂能加速自动氧化,自由基吸收剂则使稳定性提高。试验结果为亚硫酸盐氧化的自由基机理提供了有力证据,也为亚硫酸盐的贮存失效提供了有效的防止方法。     

The Role of Water in Protection Against Thermal Deterioration of Liquid Margarine

The thermal stability of liquid margarine and vegetable oils was investigated by measuring the oxidative stability index (OSI) at temperatures ranging from 90 to 180 °C, whereas total polar compounds (TPC) and tocopherols (vitamin E) were measured during heating at 180 °C in frying trays. Results showed that the OSI of liquid margarine was in the same range as the OSI of vegetable oils at lower temperatures, but at 160 and 180 °C, liquid margarine had significantly higher thermal stability, close to that observed for hard margarine and butter. The increased stability was confirmed by lower levels of TPC and a smaller relative reduction in vitamin E content during heating. Variations between different vegetable oils could partly be explained by differences in degree of saturation and level of vitamin E, with high oleic sunflower oil being the most stable oil at all temperatures. The water in liquid margarine vaporized within 1.5 min at 160 °C, and it is hypothesized that volatile pro‐oxidants are removed with the water, inducing a delay in deterioration. The results indicate a role for water in preventing lipid oxidation and decomposition in fat emulsion products at 160–180 °C, suggesting that liquid margarine, low in saturated fat, may be the healthier and preferable alternative for pan‐frying compared to other liquid vegetable oils.     

Margarines Produced From Rice Bran Oil and Fractionated Palm Stearin and Their Characteristics During Storage

Rice bran oil (RBO) usage in Southeast Asia is increasing. The purpose of this study was to incorporate RBO in margarine as a replacement for common oils such as soybean oil. The physicochemical properties of blends of RBO and fractionated palm stearin (FPS) at eleven different weight ratios (from 0:100 to 100:0) were characterized. Results showed that fat blends with ratios of 10:90, 20:80, and 30:70 RBO:FPS were semisolid at ambient temperature, with solid fat contents and a crystal morphology similar to commercial margarine fats. Blends containing ≤30% RBO were made into margarines and compared against commercial margarine over 8 weeks of storage. The margarine with a 20:80 RBO:FPS fat phase was stable against coalescence and phase separation while demonstrating acceptable spreadability and whippability at ambient temperature. Fat crystals in this blend were in the β′ polymorph at all time points during storage, which is a desired characteristic in margarine. This study showed that RBO may be effectively used for margarine production.     

Antioxidant effects of chlorophyll and pheophytin on the autoxidation of oils in the dark. I. Comparison of the inhibitory effects

The effects of chlorophyll and pheophytin on the autoxidation of oils in the dark were investigated by oven tests. The results indicated that both chlorophyll and pheophytin show antioxidant activity when methyl linoleate is used as substrate. Furthermore, chlorophyll retarded the oxidative deterioration of triglycerides in rapeseed and soybean oils at 30 C. Among the four chlorophyll derivatives (chlorophylls a and b and pheophytins a and b), chlorophyll a showed the strongest antioxidant activity. The antioxidant effects of chlorophyll and pheophytin depended on the storage temperature and the kinds of oil used as substrate.     

Rheological Properties of Sunflower Margarine

The consistency of margarine is affected by a number of different factors. The governing factors are particularly the formulation of the margarine fat and technology parameters of the processing. The effect of the margarine fat formulation on rheological properties of margarine made under constant conditions on a laboratory equipment was studied. In soft margarines to be used directly as spreads, their spreadability even at lower temperatures during the storage in refrigerator is of importance, which means that their rheological parameters (static and dynamic yield value, apparent viscosity) should be independent of temperature as little as possible in a temperature interval of 5 to 25°C. The experiments performed indicated that under the constant conditions of a laboratory preparation used, optimum rheological properties were achieved with samples prepared from a margarine fat with a composition of the 50–65% soft sunflower oil and 35–50% hardened sunflower oil 36°C.     

Untersuchungen zur Autoxidation von Fetten und Ölen mit Hilfe einer Chemilumineszenz-Methode

Investigations about the Autoxidation of Fats and Oils by a Chemiluminescence Method The oxidative stability of different oils was determined by a Rancimat apparatus. Samples of oils obtained at definite time intervals from the Rancimat were measured by a chemiluminescence method. Thereby the hydroperoxides formed during the first step of the autoxidation and radicals react in presence of a catalyst with Luminol. The results are presented in dependence of the storage time and discussed with relation to the results of the Rancimat apparatus. There is a good correlation between both methods (r = 0.9865).     

Storage stability of margarines produced from enzymatically interesterified fats compared to those prepared by conventional methods – Chemical properties

In this study, four margarine hardstocks were produced, two from enzymatically interesterified fats at 80 and 100% conversion, one from chemically randomized fat and one from physically mixed fat. These four hardstocks, blended with 50% sunflower oil, were mainly used for the production of table margarines in a pilot plant. Storage stability studies were carried out at storage temperatures of 5 and 25 °C for 12 wk. Margarines from the enzymatically interesterified fats were compared to the margarines produced by the conventional methods (chemical interesterification and physical blending) and to selected commercial margarines. The changes in the chemical properties of the products, including peroxide values (PV), tocopherols, free fatty acids, volatile oxidation products, and sensory evaluation, were examined during storage. It was observed that the margarine produced from the chemically interesterified fat had higher PV in weeks 4, 8 and 10 than the margarines produced from the enzymatically interesterified fats and the physically blended fat. These differences were not caused by different contents of tocopherols in the hardstocks. The differences between the processes for chemical and enzymatic interesterification, including further treatment stages, might be responsible for the development of a high PV in the margarine produced from the chemically interesterified fat. However, the contents of volatiles did not show the same tendency as observed for PV for the margarines stored at 25 °C during 12 wk. Storage at 25 °C accelerated oxidation compared to storage at 5 °C. The content of δ‐ and γ‐tocopherols decreased faster than the content of α‐ and β‐tocopherols during storage. This phenomenon was only affected by storage time, not by storage temperature. Sensory analysis did not show consistent differences between the produced margarines and commercial margarines, and no hydrolysis occurred for these four margarines during storage. The margarines produced from the enzymatically interesterified fats had low PV and a similar taste and smell compared to the margarine produced from the chemically interesterified fat.     

“Zerotrans” margarines: Preparation,structure, and properties of interesterified soybean oil-Soy trisaturate blends

The sodium methoxide-catalyzed random interesterification of liquid soybean oil-soy trisaturate blends was explored as a possible route to zerotrans margarine oils. Lipase hydrolysis of the rearranged fats showed that with 0.2% catalyst, interesterification is complete within 30 min at 75-80 C. The glyceride structures of natural and randomized soybean oil-soy trisaturate blends are presented, and relationships between their structure and physical properties are discussed. Organoleptic evaluations showed that randomization of the glyceride structure had no adverse effects on flavor and oxidative stability. Flavor evaluations made against a commercially hardened tub margarine oil showed that interesterified oil had comparable initial and aged flavor scores. X-ray diffraction studies demonstrated that randomized soybean oil-soy trisaturate blends possess the beta-prime crystal structure desirable for use in margarine production. Dilatometric data indicate that random interesterification of 20% by weight of soy trisaturate into the glyceride structure of soybean oil provides a product having a solid fat index suitable for use in a soft tub margarine. Presented at the AOCS Meeting, Chicago, September 1976.     

Storage of commercial margarine at different temperatures

The effect of storage temperature on the consistency of commercial margarine was analyzed by viscometry, differential scanning calorimetry (DSC), microscopy at low temperature and X-ray diffraction. The results obtained show that samples harden at 13°C and soften at 4°C. The greater strength of samples was apparently associated with crystals of higher melting points. Recrystallization takes place during storage leading to more stable solid solutions with higher melting points.     

Autoxydation der Fette in gefriergetrockneten Modellsystemen

Autoxidation of Fats in Freeze-Dried Model Systems The author describes the preparation of a freeze-dried cellulose-containing model system for the investigation of the rate of autoxidation of fats under different conditions. The increase in peroxide content as a function of the fat content and temperature was investigated in the above system. The effect of storage temperature on the induction period and the relationships between the rate of autoxidation in the initial phase and the peroxide content were determined as well.     

Kunststoffe in der Milchwirtschaft - eine kritische Studie III. Mitteilung: Verhalten verpackter Milchprodukte in Abhängigkeit von den Dichteeigenschaften von Kunststoff-Folien

Plastics in Dairy Industry - A Critical Study III: Behaviour of the Packed Milk Products in Relation to the Impervious Properties of Plastic Films The storage stability of many milk products depends decisively on the choice of a suitable packing material as well as proper packing. The prerequisite for this choice is as far as possible an exact knowledge of the critical external influences and their points of attack on the foodstuffs. Therefore it is shown, as to how, according to present knowledge, uptake and liberation of water vapour, carbon dioxide, oxygen and aroma affect the quality of milk products. The optical transparency of the plastic packings is of special interest in connection with the oxidative changes. For an effective protection of milk products by a packing with adequate impervious properties, a combination of foils must often be employed.     

Sensory stability of canola oil: Present status of shelf life studies

Sensory studies on autoxidation of canola oil, stored under several variations of Schaal Oven test conditions, suggest an induction period of 2–4 d at 60–65°C. Similar induction periods have been observed between canola and sunflower oils, whereas a longer induction period has been found for soybean oil. Canola oil seems to be more stable to storage in light than cottonseed and soybean oils but is less stable than sunflower oil. Storage stability of products fried in canola oil is similar to products fried in soybean oil. Storage stability of canola and cottonseed oils that had been used in the frying of potato chips showed that canola oil was more prone to autoxidation during storage at 40°C. The presence of light aggravated the oxidative effects and was similar for both oils. Advances in our knowledge about the shelf life of canola oil would be strengthened by standardization of Schaal Oven testing conditions and by specifying the testing protocol for photooxidation studies. Methods for training of panelists and for handling and evaluating oils and fried foods require definition. Rating scales used in the evaluation of oils need to be evaluated to ensure that reliable and valid measurements are achieved. Further progress is needed in the identification of chemical indicators that can be used to predict sensory quality of oils. Presented in part at AOCS Annual Meeting in Toronto, Ontario, Canada, May 1992.     

溶剂法制备降血糖肽固体分散体及稳定性研究

以降血糖肽为模型，Eudragit L-100和HPMC为载体，溶剂法制备了降血糖肽固体分散体，并对其稳定性和体外释放开展了研究。本文以降血糖肽固体分散体2 h的累计释放率和DPP-IV抑制率为评价指标，通过对肠溶载体和释放调节剂的比例进行优化，利用扫描电镜、傅里叶红外光谱仪和透射电镜对固体分散体进行表征，并考察了固体分散体不同储存时间和储存温度下的稳定性。结果表明，降血糖肽固体分散体的最佳比例为降血糖肽:Eudragit L-100:HPMC=1:2:0.2，此比例下制备的固体分散体2 h的累计释放率能达到93.54%，且DPP-IV抑制率仍具有较高水平。扫描电镜和透射电镜图像表明，活性肽分散在固体分散体中，红外光谱表明，活性肽二级结构的构象发生了变化。制成固体分散体后，降血糖肽的稳定性显著增强，常温储存10 d后累计释放率仍高达90.32%，在高温环境下也表现出较强的稳定性。综上所述，利用固体分散技术能在保持降血糖肽生理活性的基础上显著提高稳定性和累计溶出率，该方法对活性肽的综合利用，特别是基于活性肽的功能性食品的研发有较大的参考价值。     

Erhaltung der Margarinequalität von der Produktion bis zur Auslieferung

Maintenance of the Quality of Margarine from Production to Delivery Margarine, which is a sensitive food-stuff, requires utmost care in order that it reaches the consumer in uniform quality. Apart from the time factor, there are numerous other external influences, such as heat, light, pressure, impact etc., which impair the quality of margarine and its packing. These influences have to be encountered by preventive measures, such as proper choice of composition, manufacturing process and packaging on one hand, and maintenance of optimum conditions during storage and transport on the other. Selected examples are given to show, as to how impairing influences during storage and transport can be traced back by series of tests and the technical and organisational changes made accordingly.     

Oxidative stability,structural, and textural properties of margarine enriched with Moringa oleifera leaves extract

Consumer's demand for clean label food ingredients has driven the development of alternative food additives. This study falls within this challenge through valorization of Moringa oleifera leaves grown in Algeria as a natural antioxidant. A methanolic M. oleifera leaves extract (MOLE) was prepared and included in margarine at various levels (400, 600, and 800 ppm) and was compared to vitamin E and a margarine without antioxidants. The effect of addition of MOLE on margarine quality was studied by means of its oxidative stability, structural, textural properties, color, and aroma fingerprint. It was shown that addition of MOLE to margarine increased resistance towards oxidation, showing a higher antioxidant capacity as compared to margarine with vitamin E or without antioxidants. Moreover, addition of MOLE decreased water droplet size, which is desirable from a microbiological viewpoint since it could extend margarine's shelf life. Furthermore, addition of MOLE leads to the formation of smaller fat crystals, resulting in different fat network formation, which could be the cause of the increase in hardness seen in these margarines. Regarding sensorial effects, MOLE addition led to a significant darkening of the margarine and increase yellowness. Moreover, the aroma fingerprint showed that addition of MOLE modified the aroma fingerprint of this product.     

Effect of emulsion temperature on physical properties of palm oil-based margarine

Margarines made from refined, bleached, and deodorized palm oil at different emulsion temperatures showed no significant difference in their consistency, polymorphic behavior, and solid fat content (SFC) during storage, although differences were observed during processing. The emulsion temperatures studied were 40, 45, and 50°C, with other parameters such as emulsion flow rates, tube cooler temperature, and pin rotor speed kept constant. The SFC developed during processing and storage at 28°C was measured to evaluate the quality of margarine. The emulsion contained no SFC at any emulsion temperature studied. However, the amount of SFC in the perfector or tube cooler unit increased to 15.9, 13.9, and 15.6% in margarine produced at emulsion temperatures of 40, 45, and 50°C, respectively. At 40°C, the lowest SFC was developed during storage even though this margarine had the highest consistency. The softening point of this sample was moderately high and closely related to the type of crystal developed, which was a mixture of β′ and β crystals. Emulsion at 45°C gave the most stable margarine consistency and SFC with crystal in the β′ form even after the fourth week. At 50°C, moderately soft product was produced, which might be undesirable for some applications, although the crystals were in the β′ form.