Background. High consumption of oxysterols contributes to the development of arteriosclerosis. Thus it is necessary to monitor changes of their concentration in foodstuffs. The aim of this study was to determine the content of oxysterols in selected meats and meat products before and after heat treatment. Material and methods. Meats and meat products were pan fried in rapeseed oil for 10 minutes. Oxysterols methodology applied for the study of fat extraction, saponification, derivatization and determination by gas chromatography coupled with mass spectrometer. Results. The content of cholesterol oxidation products in meats and meat products after heat treatment (17.5 to 34.9 μg/g of fat) was statistically higher than before frying (2.2 to 10.7 μg/g of fat). Raw meats and processed meat products contained mainly cholesterol oxidation products which equalled from 1.0 to 8.3% of cholesterol content. In fried meats and meat products has been found phytosterol oxidation products (0.1-1.7 μg/g of fat) but only in small amounts. Conclusions. The increase in the content of phytosterol oxidation products in analysed meat samples after frying was probably the result of intensive phytosterol oxidation in-cluded in the rapeseed oil, also induced by haeme dyes within meat. From the results of the samples analyzed, it seems that multiple parameters are associated with the formation of oxysterols. Further studies should be performed to identify the factors e.g. water content, pro-oxidants, exposure to light, storage time and conditions, that may affect oxysterol formation during home frying.
A study was carried out to determine the cholesterol and cholesterol oxidation products (COPs, oxysterols) content of several Polish commercial sausages. Cholesterol content ranged from 244.42 µg/1 g of sample in salami to 847.87 µg/1 g of sample in pasztetowa no. 1. The content of the sum of cholesterol oxidation products ranged from 4.42 µg/1 g of the sample in parówkowa to 36.52 µg/1 g of the sample in metka łososiowa. The correlation between fat and cholesterol oxidation products showed that in case of the higher the fat content, the higher the sum of oxysterols content is observed. A correlation between fat content and cholesterol content was not found.
Background. Meat products belong to products particularly at risk of fat oxidation processes. One of the methods to prevent disadvantageous oxidative changes of lipids in food is the application of antioxidants. Material and methods. The experimental material consisted of fine - ground model sausages. Produced processed meats differed in terms of the presence and amount of acid and enzymatic soy hydrolysates (0.3% and 0.7%). The reference sample comprised processed meat product with no hydrolysate added. Model processed meat products were stored at 4°C for 29 days. The analyses included changes in peroxide value, changes in cholesterol and its oxidation products. Results. It was found that changes of peroxide value, 7α-OHC, 7β-OHC, α-epoxy-C, β-epoxy-C, 20α-OHC, 25-OHC and total oxisterols were statistically significantly af-fected, apart from storage time, also by the type and level of applied hydrolysates. The addition of enzymatic and acid hydrolysates to batter of experimental sausages effectively inhibited the process of fat oxidation. Conclusions. In samples with enzymatic hydrolysate an approx. 20% loss of initial cholesterol content was recorded. In contrast, in the other samples this loss amounted to approx. 10%. The process of cholesterol metabolism in tested processed meat products was affected by their storage time and the type of added hydrolysate. It was observed that the highest dynamics of cholesterol metabolism occurred in a sample with no hydrolysate added. The level of total oxisterols in the sample with no addition of hydrolysate was over two times higher than in samples with an addition of hydrolysate.
The aim of the study was to determine contents of phytosterol and oxyphytosterols in soybean oil and soybean oil with the addition of sea buckthorn seed oil after thermal processing, and to assay the oxidative stability of the oils. The analysis verified that the thermal processing of soybean oil at 120°C induced a decrease in total phytosterols (phytosterols concentration was reduced by 5.2 to 21.0%) and formation of the following phytosterol oxidation products: 7-ketositosterol, 5α,6α-epoxysitosterol, 7-ketocampesterol, 5α,6α-epoxycampesterol, 7-ketostigmasterol, and 5α,6α-epoxystigmasterol. The content of phytosterol oxidation products (POPs) increased with the higher sea buckthorn seed oil addition to soybean oil (from 1.2 mg/100 g in soybean oil with 1% addition of sea buckthorn oil to 11.4 mg/100 g in soybean oil with 5% addition of sea buckthorn oil) during Rancimat test.
The effect of storage on the contents of cholesterol, its oxidation products (oxysterols), lipid oxidation and hydrolytic changes in liver pate type sausage was studied. Lipid oxidation, hydrolysis and oxysterols level were examined after 1, 3, 6, 8 and 10 days of storage at 4°C. 7b-hydroxycholesterol and 7 ketocholesterol were the major cholesterol oxidation products formed in samples during storage and their amounts increased throughout storage time. Storage time had no significant effect on acid number and lipid oxidation products (TBARS) in sausage. Significant increase (p = 0.05) of peroxide value, 7b-hydroxycholesterol, 7ketocholesterol levels and total of oxysterols was noted. Storage time had a significant effect on the decrease of cholesterol. The contents of particular oxysterols and their sum were closely related to the peroxide value.
Oceniono stopień oksydacji tłuszczu wyodrębnionego z jaj kurzych usmażonych z dodatkiem masełka Ekstra Mazurskiego, margaryny Delmy i Masła Roślinnego. Przeprowadzono również badania jakości wymienionych tłuszczów modyfikowanych oraz tłuszczu wyekstrahowanego z żółtek jaj, przed poddaniem ich obróbce kulinarnej. Stwierdzono, że tłuszcz jajowy wykazywał wysoką wartość liczby anizydynowej, przekraczającą czterokrotnie liczbę wyznaczającą dobrą jakość tłuszczu. Zawartość nadtlenków w tłuszczach z usmażonych jajecznic nie przekraczała dopuszczalnych norm.
W pracy określano podatność aminokwasów występujących w postaci jonu obojnaczego i postaci kationu na reakcje z produktami utleniania tłuszczu. Prowadzono badania modelowe w emulsjach estrów metylowych kwasów tłuszczowych: dokozaheksaenowego, linolowego, oleinowego i stearynowego.
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