Die Bestimmung des Fettgehaltes von Kartoffelfritierprodukten durch NMR

Determination of Fat Content in Fried Potato Products by NMR Since determination of the fat content by NMR in rape seed and mize is well proved it was tried to use this method for fat content determination in fried potato products (chips and pommes frites), too. At first it was found that the high water content of pommes frites requires predrying. This can remain undone for chips, if the residual water content does not exceed 3%. Measurement by NMR is only possible if the Same fat or oil of production is used as reference. Further it was found that the fat quality which deteriorates continuously during frying leads to considerable deviations in NMR measurement. This involves that the product sample, which is to investigate, has to be taken always together with the fat sample. If all these requirements are met, differences up to 4% fat can occur in comparison between NMR determination and petrolether extraction.     

Antioxidant activity of tocopherols,ascorbyl palmitate,and ascorbic acid and their mode of action

In the quest to use antioxidant compounds occurring in nature or related compounds, extensive studies have been made on vegetable oils, animal fats, apocarotenal, and vitamin A as substrates with ascorbyl palmitate, tocopherols, and ascorbic acid as antioxidants. Antioxidant efficiency varies with the substrate. Ascorbyl palmitate at a level of 0.01% provides a useful increase in the shelf-life of vegetable oils. Alone it is better than butylated hydroxytoluene and butylated hydroxyanisole and in combinations with other known antioxidants improves the shelf-life of all vegetable oils, as well as potato chips. Solubility problems with ascorbyl palmitate and other esters of ascorbic acid are discussed. The tocopherols have their greatest effect in protection of animal fats, carotenoids, and vitamin A. Experiments utilizing tocopherols and tocopherol combinations are presented. The activity of ascorbic acid, an excellent scavenger of oxygen, is reviewed. Quenchers of singlet oxygen do not inhibit the direct oxidation of fats and oils under the conditions used.     

Zur Analytik und Beurteilung von Fritürefetten I

Analysis and Evaluation of Frying Fats As a result of Changed eating habits, the production of Fried food-stuffs has considerably increased withing the Past years. Since the consumer ingests along with the fried food-stuff also a part of the fat employed for frying, the hazard to health due to intake of overheated fat can not be ruled out. the results of investigations on frying fats and food preparations have been presented from the view-point of food control. Studies are reported on: 1) frying of pommes frites in various fats; 2) frying of fish in various oils; 3) investigation of samples from various manufacturers; and 4) permissible limits in the evaluation of heated fats.     

Die Veränderungen von Nahrungsfetten bei höheren Temperaturen

Alterations of Edible Fats and Oils at Elevated Temperatures Refining of vegetable fats and oils has no deleterious effect upon their composition as far as desliming, neutralization or bleaching is concerned. However, during deodorization or physical refining small amounts of dimeric triglycerides and of trans fatty acids are formed depending on temperature and duration. The amounts of these by products are insignificant provided that the usual process conditions are applied. In the kitchen the various cooking methods can have quite different effects upon the quality of the fats and oils. Whereas boiling and baking have no effects and short-term shallow frying show only minor changes in quality, deep-fat frying can cause serious alterations especially if the oil is used far too long. Numerous investigations tried to identify these chemical reactions which are predominatly isomerizations as well as polymerization and oxidation reactions. The German Society for Fat Science and Federal Health Authorities in Germany issued recommendations for the assessment of fat deterioration basing on sensory evaluation in combination with some analytical data. Since 60 years and with considerable effort more or less systematic investigations have been performed to answer the question if heated fats are detrimental to human health. Fats and oils were heated under the conditions of good commercial practice and then fed to test animals. In some cases the heated fats were separated into various fractions and these were fed individually. The results of the most significant long-term feeding trials are reported and critically evaluated.     

Oxidative stability of potato chips determined by Rancimat

During recent years the Rancimat apparatus has been used extensively to determine the stability of fats and oils. Most stability tests for fat-containing foods are performed on the extracted oil. The objective of this research was to observe the behavior of potato chips in the racimat without oil extraction. Determinations were carried out at 110°C and 20 L/hr air flow. The curves for the ground chips were completely different from those obtained with extracted oils. Curves for fresh potato chips showed two inflection points after approximately 5 and 20 hr, respectively. Sensory analyses (odor score) of samples withdrawn from the Rancimat after 0, 5, 10, 20 and 25 hr showed significant differences (P < 0.01). An odor score of 5 was considered the rejection point, and was equivalent to 10.8 hr and corresponded to 150 μs of electric conductivity. At this point, the curves started to level off between the first and second inflection points. Curves obtained with potato chips stored at 25°C for 2, 4, 6, 8, 10 and 12 wk showed the same basic pattern, although prolonged storage corresponded with lower induction time. Correlation of induction values between ground potato chips and extracted oil was high (r > 0.87). From these results, it seems that it is possible to estimate the oxidative stability of fatcontaining foods without prior extraction. Presented at 81st AOCS Annual Meeting, Baltimore, MD, 1990.     

Tocopherole — Antioxidative Wirkung bei Fetten und Ölen

Tocopherols — Antioxidative Effect on Oils and Fats The main reason for the deterioration of fats and oils is a chemical reaction between the oxygen and the double bonds which are contained in the unsaturated fatty acids. In the course of the autoxidation intermediate peroxides affect the vitamines sensitive to oxidation. They lower the content of physiologically valuable essential fatty acids. The oxidation stability of oils and fats depends on the natural content of tocopherols as well as on the composition of the fatty acid. The effect of the added tocopherols depends on the natural content of tocopherols. Lipids with lower contents can be stabilized very well with antioxidants consisting of tocopherols. Here animal fats as well as synthetical lipids are considered which in particular are used in cosmetic industry and in the field of pharmacy but also in food industry. Vegetable oils contain, due to their nature, high contents of tocopherols which are partly removed or oxidised during raffination and storage. Therefore adding antioxidants containing tocopherols is adviseable. Also an addition of reducing substances as for instance ascorbylpalmitate is recommended. Moreover antioxidant systems should consist of heavy metal chelating substances.     

Lipid oxidation in potato chips

Qualitative and quantitative analyses of volatile compounds in fresh and aged potato chips and unused fresh and aged frying oils showed that oxidation of oils was mainly responsible for volatile compound changes in potato chips during storage. The lipid oxidation of potato chips was determined by measuring the peroxide value of potato chips and the amount of volatile compounds and oxygen content in the headspace of potato chip bottles by gas chromatography. The correlation coefficients between volatile compounds and oxygen content, volatile compounds and peroxide value, and peroxide values and oxygen content were -0.93, 0.95 and -0.93, respectively. These high correlation coefficients indicated that volatile compound changes in potato chips during storage were mainly due to the oxidation of oil. The lipid oxidation of potato chips during storage can be studied by measuring oxygen content and the amount of volatile flavor compounds in the headspace. The potato chips produced in oil containing an antioxidant tertiarybutyl hydroquinone (TBHQ) had better oxidation stability than the chips fried in oil without TBHQ.     

Effect of heat and frying on sunflower,oil stability

Sunflowers are one of the most important sources of vegetable oils in the world, second only to soybeans. Although in use throughout many parts of the world, sunflower seed are just now beginning to attact attention and use in the United States. Composition of the oil appears to be dependent on area of production. Sunflower oil from seed grown in northern US typically contains 70% linoleic acid. In contrast, oil from seed produced in the South generally contains 40–50% linoleic acid and is higher in mono-unsaturated fats. For most of the edible oil market, sunflower oil appears to have an advantage over most other vegetable oils. Lightly hydrogenated sunflower oil was compared with a cottonseed-corn oil mixture for frying potato chips. Organoleptic evaluation indicated that chips did not differ significantly. We also evaluated the useful life of various sunflower seed oils for deep-fat frying. Hydrogenated and unhydrogenated sunflower oils and a commercial shortening were used to deep-fry raw potatoes. A plot of the log of the Active Oxygen Method (AOM) values of the oils versus time gave a straight line, the slope of which reflects the oxidizability of the oil. Data indicated that lightly hydrogenated northern sunflower oil was much less prone to oxidation after abuse than the commercial shortening and was useful for a longer time. The southern oil deteriorated faster than the northern sunflower oil, but the two oils were processed differently. Thus, in recent work, care was taken to process both northern and southern grown sunflower seed under identical conditions. Frying studies indicated that oil from southern grown seed was more stable than that from northern seed as would be expected from their fatty acid composition.     

Frying quality and stability of low-and ultra-low-linolenic acid soybean oils

To determine effects of very low levels of linolenic acid on frying stabilities of soybean oils, tests were conducted with 2% (low) linolenic acid soybean oil (LLSBO) and 0.8% (ultra-low) linolenic acid soybean oil (ULLSBO) in comparison with cottonseed oil (CSO). Potato chips were fried in the oils for a total of 25 h of oil use. No significant differences were found for either total polar compounds or FFA between samples of LLSBO and ULLSBO; however, CSO had significantly higher percentage of polar compounds and FFA than the soybean oils at all sampling times. Flavor evaluations of fresh and aged (1, 3, 5, and 7 wk at 25°C) potato chips showed some differences between potato chips fried in different oil types. Sensory panel judges reported that potato chips fried in ULLSBO and aged for 3 or 7 wk at 25°C had significantly lower intensities of fishy flavor than did potato chips fried in LLSBO with the same conditions. Potato chips fried in ULLSBO that had been used for 5 h and then aged 7 wk at 25°C had significantly better quality than did potato chips fried 5 h in LLSBO and aged under the same conditions. Hexanal was significantly higher in the 5-h LLSBO sample than in potato chips fried 5 h in ULLSBO. The decrease in linolenic acid from 2 to 0.8% in the oils improved flavor quality and oxidative stability of some of the potato chip samples.     

Effect of γ-tocopherol on formation of nonvolatile lipid degradation products during frying of potato chips in triolein

Formation of undesirable odors and flavors during food processing operations is an important problem for the food industry. To determine the effect of γ-tocopherol on these negative attributes of fried food, we fried potato chips in triolein with 0, 100, or 400 ppm γ-tocopherol. Triolein extracted from potato chips was sampled for residual γ-tocopherol and nonvolatile degradation products after the chips were aged. RP-HPLC coupled to atmospheric pressure chemical ionization MS and size-exclusion chromatography was used to analyze, samples for degradation products in the triolein absorbed in potato chips as well as the fryer, triolein. MS results showed that γ-tocopherol reduced the production of nonvolatile degradation products in the triolein absorbed by the potato chips and in the triolein in the fryer. Fryer oil samples and extracted potato chip oils with 400 ppm γ-tocopherol had a significantly lower production of degradation compounds than did samples with 100 ppm γ-tocopherol. Both fryer oils and potato chips containing 100 ppm γ-tocopherol had significantly fewer nonvolatile degradation products than did the samples without γ-tocopherol. These nonvolatile compounds are known precursors of negative odors and flavor compounds produced during the frying and aging of foods.     

Verhalten und Beurteilung von Fritierfetten in der Praxis

Behaviour and Assay of Frying Fats in the Practice Studies on coconut oil palm oil, peanut oil, soybean oil and hardened peanut and fish oils revealed that the oils rich in polyenoic acids as well as animal fats are unsuitable for prolonged use in frying. The content of oxidized fatty acids, saponification colour number, flavour, acid value, smoke point and appearance served as criteria for assay. The limiting values determining whether the frying fat is edible, and the significance of each of these characteristic properties used for such evaluations are discussed. Finally, a new rapid method is introduced for the direct determination of the degree of oxidative deterioration in frying plants. This methods can be practiced without a prior knowledge of chemistry.     

Composition of oils extracted from potato chips by supercritical fluid extraction

To determine effects of two extraction procedures on oil compositions, tocopherols, monoacylglycerol, diacylglycerol, triacylglycerol, free fatty acids, polymers and polar components were determined in oils after extraction from potato chips by either supercritical carbon dioxide or hexane. Potato chips were fried in cottonseed oil or low linolenic acid soybean oil and sampled after 1, 10 and 20 h of oil use. Both extraction methods recovered comparable amounts of oil from the potato chips. Compositions of triacylglycerol and non‐triacylglycerol components including tocopherols, monomer, polymer, monoacylglycerol, diacylglycerol were similar for samples of chips fried in either oil except for the δ‐tocopherol data for potato chips fried in the low linolenic acid soybean oil used for 10 h of frying. There were some differences between the composition of low linolenic acid soybean oil extracted from the potato chips compared to the fryer oil at the 20 h sampling time. These results showed that the supercritical carbon dioxide extraction gave similar results to hexane extraction in yield and composition of oils from potato chips.     

The use of antioxidants in potato chipping

Summary Laboratory and commercial-scale fryings of potato chips have been made with various vegetable oils, vegetable shortenings, lard, and combinations of these. Fryings have been made with and without the addition of butylated hydroxyanisole as an antioxidant. The data from both types of experiments indicates that butylated hydroxyanisole possesses “carrythrough” antioxidant properties not only in animal fats but in vegetable oils and vegetable shortenings also. Data also indicates that the addition of propyl gallate and citric acid as synergists to the butylated hydroxyanisole increases the “carry-through” antioxidant properties. Presented at 23rd Fall Meeting, American Oil Chemists’ Society, Chicago, Ill., Oct. 31, Nov. 1 and 2, 1949. The Schaal Oven Tests were conducted at 145°F.     

Die weitere Entwicklung der Codex Alimentarius Standards für Öle und Fette

Further Development of Codex Alimentarius Standards for Oils and Fats The present status of Codex Alimentarius Standards for oils and fats is reviewed. Further development of these standards is reported, based on discussions at the 8th meeting of the codex committee for oils and fats in London. The discussions concerned standards for low-erucic rapeseed oil, low-fat spreads, coconut-, palm-, palm kernel-, babassu-, grape seed- and marine oils as well as issues involving the range of application, fatty acid composition of individual oils and fats and use of solvents in the recovery and processing of fats.     

Die Weiterentwicklung der Codex Alimentarius Standards für Öle und Fette

Further Development of Codex Alimentarius Standards for Oils and Fats A report is given on the further development of Codex Alimentarius Standards for oils and fats, which was discussed in the 9th meeting of the Codex Committee on Fats and Oils from 28th November to 2nd December 1977 in London. Topics discussed were a collaborative report by FAO and WHO on the role of fats in human nutrition, the general standard for oils and fats, and standards for reduced fat margarine, low erucic acid rapeseed oil, coconut oil, palm oil, palm kernel oil, babassu oil, grape seed oil as well as marine oils. Furthermore, the limits of fatty acid composition as criteria for identification of specific oils and fats were discussed.     

Comparison of flavor compounds of potato chips fried in palmolein and silicone fluid

The importance of the frying oil as a heat-transfer medium and as a source of flavor precursors for the formation of potato chip flavor was investigated. Potato slices were fried in palmolein or silicone fluid, and the volatile flavor compounds of the resulting chips were isolated onto Tenax and analyzed by gas chromatography-mass spectrometry. Although the heat-transfer coefficients of the oils did not differ significantly, their temperature profiles during frying were different, probably due to greater turbulence on placing potato slices in palmolein, leading to more efficient heat transfer. Levels of Strecker aldehydes and sulfides in chips fried in the two media were not significantly different, but levels of pyrazines were significantly higher in palmolein-fried chips. Amounts of 2,4-decadienal were also significantly higher in palmolein-fried chips, but there was no significant difference in hexanal levels between the samples.     

Composition and control of potato chip frying oils in continuing commercial use

Summary The oils in use on a continuing commercial basis in the production of potato chips on a nation-wide scale are found to be free of thermal polymers. This conclusion is supported by the similarity in physical properties and in chemical composition between the fresh and heated oil in any one operation. In a) degree of unsaturation of oils, b) melting point, c) setting point, d) fatty acid composition, e) free fatty acid content, f) concentration of fatty acid isomers, g)solids content index, and h) in the crystallizing properties of the oils, there are no differences between fresh and heated oil of such magnitude to warrant criticisms of the wholesomeness of the oil being absorbed by the chip. The constancy in composition between heated and fresh oil, particularly with respect to the essential fatty acid content, which is largely responsible for the noncaloric functions of fats in the diet (19), permits the same conclusions to be made in regard to the nutritive value of the heated oils,i.e., of the triglycerides contained therein, as have been drawn from studies conducted on the corresponding fresh oils. Based upon statistical quality control considerations, the oils employed in the survey of the potato chip industry have been characterized by having a free fatty acid value of no greater than 0.60% and a decrease in iodine value of no greater than 3.0% in 95% of the operations. These control limits characterize the oils, which, on test, have led to the generalization about the absence of thermal polymers in commercial potato chip frying oils. Much of the material in this paper and in one recently published (1) was presented at the 48th Annual Meeting of the American Oil Chemists' Society in the Symposium on “Fats in Nutrition and Health,” New Orlens, La., April 30, 1957.     

Palm oil products in cooking fats

Palm oil and its products are used widely, either on their own or in combination with other oils and fats, to make products for cooking and other applications such as baking, icing, filling and topping. Palm oil and its products are not only cheaper to process but also impart into the product the functional properties demanded by some of these applications. Legislation governing production and marketing of these products in some of the important countries is reviewed. The physico-chemical characteristics of products marketed in different countries are also presented. Formulations based on palm oil and its products are suggested to make low or notrans acid fats and high PUFA fats.     

Effect of fatty acid composition of oils on flavor and stability of fried foods

Effects of fatty acid composition of frying oils on intensities of fried-food flavor and off-flavors in potato chips and french-fried potatoes were determined. Commercially processed cottonseed oil (CSO) and high-oleic sunflower oil (HOSUN) were blended to produce oils with 12 to 55% linoleic acid and 16 to 78% oleic acid. Analytical sensory panels evaluated french-fried potatoes and pilot plant-processed potato chips. Initially, both foods prepared in CSO (16% oleic/55% linoleic acid) had the highest intensities of fried-food flavor; however, this positive flavor decreased with decreasing levels of linoleic acid. 2,4-Decadienal in potato chips also decreased with decreasing linoleic acid in the oils. Frying oil stability, measured by total polar compounds (TPC), and oxidative stability of potato chips, measured by volatile compounds, showed that HOSUN (78% oleic acid) produced the lowest levels of TPC and the lowest levels of hexanal and pentanal, indicating greater frying oil stability and oxidative stability of the food. However, fresh potato chips fried in HOSUN had the lowest intensities of fried-food flavor and lowest overall flavor quality. Fried-food flavor intensity was the best indicator of overall flavor quality in fresh potato chips. Volatile compounds, TPC, and oxidative stability index directly varied with increasing oleic acid, and were therefore not directly indicative of flavor quality. No oil analysis predicted flavor stability of aged potato chips. Compositions of 16 to 42% oleic acid and 37 to 55% linoleic acid produced fresh fried-food with moderate fried food flavor intensity, good overall flavor quality, and low to moderate TPC levels (chips only). However, in aged food or food fried in deteriorated oil, compositions of 42 to 63% oleic and 23 to 37% linoleic provided the best flavor stability.     

Fluid shortening medium

Because of an apparent interest in a liquid shortening with good baking properties, a program for the development of such a product was instituted. Past efforts to accomplish this by dissolving or suspending emulsifiers in vegetable oils had not had notable, success. In this instance it was decided to use a different approach, that of making an emulsion in water, in trying to impart desirable baking properties to vegetable oils. It was also desired that a fluid product be produced from animal or hydrogenated vegetable fats, using the same approach. Shortening emulsions were prepared by using sorbitan monostearate, polyoxyethylene-2-sorbitan monostearate, and mono-and diglycerides as dual-purpose emulsifiers to provide a stable emulsion and impart good baking properties. Emulsions were prepared and tested and found capable of utilizing all common shortening base-stocks in baking. In most cases also excellent results in cream icings were obtained. The most serious problem which occurred was the tendency of emulsions made with animal fats to become plastic. A study of the causative factors was made, and the conclusion was reached that a stable fluid products could be obtained through careful selection of ingredients. Important factors which affected emulsion viscosity were monoglyceride level and hardness; the ratio of sorbitan monostearate to polyoxyethylene sorbitan monosterate, and their level; and the shortening basestock used. The stability of the emulsions was studied and the conclusions were reached that aging did not affect baking quality significantly although optimum effectiveness was reached apparently several days after preparation; the emulsions were not particularly subject to oxidative rancidity; bacteria and mold counts increased only slightly during storage periods as long as two months at room temperature. An unexpected result was the markedly-improved performance when the shortening was pre-emulsified as shown by the baking data and icing quality factors which were reported.