Effects of heat treatment on the stability of lard

1-Substituted pyrroles (1 and 2) and 1-substituted 2-(l'-hydroxypropyl)pyrroles (3)(4)(5) were produced in reactions between a lipid peroxidation product, 4,5(E)-epoxy-2(E)-heptenal, and the amino acid lysine. The antioxidative activity of compounds 1-5 was studied. Oxidative stability was evaluated in refined soybean oil containing compounds 1-5, buty[ated hydroxytoluene (BHT), n-propyl gallate or L-lysine, at concentrations of 50-200 ppm. Oils were either oxidized at 60°C and oxidation products determined by the thiobarbituric acid-reactive substances assay, or they were oxidized at 110°C by the Rancimat method. Although both methods gave similar results, greater differences were observed at 60°C than at 110°C. Addition of compounds 1-5, L-lysine, BHT, and propyl gaiiate significantly (P < 0.01) protected the oil against oxidation. The effectiveness order found was: L-lysine << compounds 3-4 < compounds 1-2 < compound 5 = BHT << propy [ gallate. JAOCS 72, 1571[ gallate. JAOCS 72, -1575[ gallate. JAOCS 72, (1995.

mentioning

confidence: 96%

Natural antioxidants produced in oxidized lipid/amino acid browning reactions

Alaiz

Zamora

Hidalgo

1995

“…The increased stability of sugar cookies has been attributed to the formation of reducing substance during baking (4). Lips (10) however found that lard heated in the presence of proteins and carbohydrates required temperatures of 280-296~ before any improvement in stability was obtained.…”

mentioning

confidence: 99%

Amino‐hexose‐reductones as antioxidants. I. Vegetable oils

Evans

Moser

Cooney

et al. 1958

Summary Amino‐hexose‐reductones were evaluated as antioxidants in soybean, cottonseed, and corn oils and were shown to be highly effective by all oxidative and chemical tests. The activity of the eight different reductones was approximately the same in any one substrate. Slightly higher activities were given by reductones of lower molecular weight. Activity was demonstrated at concentrations as low as 0.001% and was shown to be a linear function of the concentration up to 0.02%, the approximate limit of solubility. Out‐standing features of the reductone‐treated oils were long induction periods, slow absorption of oxygen, and low rates of peroxide development. Reductones are believed not to react directly with peroxides but to prevent peroxide formation by reacting with some precursor. The combination of reductones with other antioxidants showed synergistic effects in only one sample of corn oil. The activity of combinations in soybean and cottonseed oils was for the most part strictly additive. In soybean oil, citric acid‐reductone combinations with each at the 0.01% level gave a slight improvement over the expected activity. Oils stabilized with multiple‐component, antioxidant mixtures in which an amino reductone replaced propyl gallate showed less peroxide development and were equally acceptable according to organoleptic scores. Aged oils did not show the organoleptic improvement that would be expected from the marked improvement observed in the oxidative stability. Significant improvements in flavor stability could be observed with reductones only when they were used in combination with an‐other antioxidant. Reductone‐treated soybean and cottonseed oils did not show an appreciable improvement in flavor stability. Only the di‐n‐butylamino‐and diallylamino‐reductones contributed foreign flavors to the oil. Atypical flavors are believed associated with the amine moiety of the reductone. At high temperatures and at higher concentrations of reductones a brown melanoid color develops in the oil. The anhydro derivatives developed more color than the normal reductone. The reductones do not withstand oil deodorization conditions.

“…Studies under controlled laboratory conditions have shown that chemical changes which occur in a fat during heating are dependent on many factors. Some of these factors are: length of time fat is exposed to heat and the temp (2); presence of accelerators of oxidation such as oxygen or oxidation products (3,4) ; mixed fatty acid composition and the position of the fatty acid in the triglyceride (5); presence of metallic ions such as iron (1) ; presence or addition of hematin compounds (6) ; presence of water vapor (4) ; amt of fat heated/ unit of surface area (7); presence of amino acids and carbohydrates (8,9); and processing conditions used to refine, dccolorize and deodorize the fat (10).…”

Section: Introductionmentioning

confidence: 99%

“…Mehlenbacher (7) presents an excellent review of the pertinent literature through 1952. Siggia et al (8) use pyromellitic dianhydride to esterify alcohols, while Sully (11) employs stearie anhydride and elevated temp. Burton and Praill (2,3) described a reaction mechanism for perehloric acid catalyzed acetylation which was later used by Fritz and Sehenk (6), who extended it to include the pyridinium acetylinium ion suggested by Gold and Jefferson (5).…”

Section: Introductionmentioning

confidence: 99%

Fatty acid components of fried foods and fats used for frying

Kilgore

Luker

1964

Oxidation of fat is accelerated at temp as high as those used for frying. The extent of this oxida‐tion has been studied by frying two kinds of foods (chicken or potatoes) in cottonseed oil and in lard. Fat samples, taken prior to use and follow‐ing 5 and 10 hr of frying (both for chicken and potatoes) were esterified. Subsequent quantita‐tive assays of methyl esters by gas chromatogra‐phy showed that the linoleic acid content had decreased from 57‐49% after cottonseed oil had been used 10 hr for frying. This decrease was present regardless of whether chicken or potatoes were fried. There was no change in the linoleic acid content of lard after chicken was fried, but a decrease from 11.3‐5.8% was noted when pota‐toes were fried for 10 hr. The fatty acid content of the fat extracted from the potatoes and the fat used to fry them, was the same when sampled at 5 hr. However, at the end of the 10‐hr frying period, fat ex‐tracted from the potatoes had a lower linoleic acid content than fat used to fry them. Results were the same for both cottonseed oil and lard. Fatty acid components of the fat extracted from the chicken seemed to be affected as much by the fatty acid composition of the chicken itself as by fat used for frying. Whether the chicken was cooked in fat used 5 or 10 hr made little differ‐ence.