Preservation of thiamine, riboflavin, niacin and ascorbic acid in vitamin-enriched minced meat products after different types of heat processing

Enrichment of meat chopped products with thiamin, riboflavin, niacin and ascorbic acid in a dose of 1, 1.25, 10 an 75 mg (respectively) per portion provides their content in prepared products comprising a half of the daily requirements of a human in these vitamins. Different types of heat treatment (routine frying, IR- and UHF-heating) lead to relatively high preservation of the vitamins added (70-90%). It is recommended that meat chopped cutlets be used as vitaminization objects.     

Photochemical interaction of ascorbic acid with riboflavin, nicotinamide and alpha-tocopherol in cream formulations

The present work is based on a study of the effect of some vitamins such as riboflavin (RF), nicotinamide (NA) and alpha‐tocopherol (TP) on the photodegradation of ascorbic acid (vitamin C) (AH₂) in oil‐in‐water cream formulations using a UV irradiation source. A UV spectrophotometric and the official iodimetric methods have been used for the assay of AH₂ in cream formulations. These methods have been validated in the presence of RF, NA and TP before their application to the creams. The recoveries of AH₂ in the creams are in the range of 90–95% and the reproducibility of the method is within ±5%. The apparent first‐order rate constants (k_obs) for the photodegradation of AH₂ in the presence of RF, NA and TP, individually, in the creams have been obtained. The second‐order rate constants for the photochemical interaction of AH₂ and the vitamins RF, NA and TP have been determined from the plots of k_obs for AH₂ photolysis versus the individual vitamin concentration along with the values of k₀ from the intercept on the vertical axis. The values of k₀ in the presence of RF and NA are lower than those of the k_obs, indicating that these vitamins act as photosensitizers for the degradation of AH₂ in creams. On the contrary, the value of k₀ in the presence of TP is higher than that of the k_obs, suggesting a stabilizing effect of this vitamin on the degradation of AH₂ in creams. The mode of interaction of the individual vitamins with AH₂ on photolysis has been discussed.     

肉制品中亚硝胺的形成及影响因素的研究进展

亚硝胺是毒性和危害作用很强的一类化学致癌物质,在肉制品特定的加工环境中容易生成。本文介绍了亚硝胺的结构及其致癌性、亚硝胺的形成机理和亚硝胺对人体危害的途径,并就影响亚硝胺生成的因素以及减少亚硝胺生成的措施的研究进行了综述。为实际生产中控制亚硝胺的形成提供一定的理论基础。      

Effect of several heat treatments and frozen storage on thiamine, riboflavin, and ascorbic acid content of milk

This research was designed to test the reliability of modified Association of Official Analytical Chemists methods for quantitation of thiamine, riboflavin, and ascorbic acid in milk; to ascertain the extent of destruction of those vitamins by modern heat processing; and to determine if it is truthful to report that heat processing does not reduce milk's nutritional properties insofar as those vitamins are concerned. Milk was processed continuously at four time-temperature treatments, including that used for modern commercial sterilization. Both raw and heated milks were analyzed immediately for content of heat labile vitamins; subsamples were packaged in amber plastic bottles, frozen, and subsequently analyzed for vitamin content after 14 days storage. Analyses were by modified Association of Official Analytical Chemists fluorometric techniques.     

Prediction of thiamine content in convective heated meat products

It is reported that thiamine is one of the most heat labile water soluble vitamins. It is therefore important to control the destruction of this vitamin during heating, reheating and keeping warm of different food items.
In this study the kinetics of thiamine degradation in ground meat were determined. The losses during roasting of a minced meat loaf under different air conditions in a forced convection oven were calculated by computer simulations. The actual losses were analysed by a chemical method. The kinetics were found to be approximately of first order. The time-temperature curves and the thiamine degradation in the loaves roasted under fairly mild conditions were easier to predict than the ones roasted at higher air temperature. This is partly due to the formation of the crust which has different thermal properties and gives different chemical changes from the inner parts of the loaf. The humidity and the velocity of the air does not effect the crust formation as much as the air temperature. This fact limits the prediction of thiamine degradation to lower air temperatures.     

气相色谱-质谱法测定肉制品中的亚硝胺

利用二氯甲烷提取肉制品中的3种挥发性亚硝胺,即:N-二甲基亚硝胺(NDMA)、N-二乙基亚硝胺(NDEA)、N-二丙基亚硝胺(NDPA)。利用气质联用仪采用选择离子法(SIM)进行定性定量检测。本检测方法前处理简单快捷,易于操作,线性相关系数分别可达0.9991、0.9991、0.9995;线性范围分别可达0~250μg/mL;方法重现性良好,其RSD可达1.44%~1.99%;回收率可达90%~105%;灵敏度高,检测限分别为0.04μg/kg、0.025μg/kg、0.01μg/kg。     

The effect of germination process on the superoxide dismutase-like activity and thiamine,riboflavin and mineral contents of rapeseeds

Seeds of double low oilseed rape variety Mango (Brassica napus, var. oleifera) were subjected to a 7-day germination at 25 °C and 95% moisture content in darkness in a conditioning cabinet. The effects of the germination process on the superoxide dismutase-like activity (SOD-like activity), thiamine (vitamin B₁) and riboflavin (vitamin B₂) and minerals, such as Ca, Mg, Cu, Fe and Mn, were studied. Correlations between individual mineral contents, vitamin B₁ and B₂ contents, and the ability of phosphate buffered saline (PBS) extracts from germinated rapeseed to scavenge superoxide anion radicals in vitro were also investigated. SOD-like activity showed a gradual increase after the second day of germination, reaching a maximum level on the sixth day, and remained almost constant up to the end of the germination period. During germination, thiamine underwent a progressive decrease up to the sixth day, reaching a constant level between the sixth and the seventh day. In contrast, riboflavin content increased throughout the germination period up to the fifth day, and after that a constant level was observed. Levels of Ca and Mg were almost constant up to the fourth day and after that an increase of these minerals was observed. Cu and Mn increased during the germination process, and retentions of 33% and 22%, respectively, were observed at the end of germination. Fe content dropped after 1 day of germination and from there onward it started to increase gradually and an 18% retention was observed in 7-day germinated seeds. Positive correlations between SOD-like activity and riboflavin (r = 0.87), Cu (r = 0.74) and Mn (r = 0.87) were found during rapeseed germination.     

肉制品中亚硝胺形成影响因素和控制措施研究进展

亚硝胺是在弱酸性条件下由亚硝酸盐和胺类物质反应生成的一种致癌物质。本文阐述了亚硝胺形成机理及影响因素,并介绍了亚硝胺控制措施的研究进展,为亚硝胺的控制提供参考。      

Determination of ascorbic and isoascorbic acid in beverages and additives to meat products by capillary isotachophoresis

 A isotachophoretic method with conductivity detection was developed to directly determine ascorbic acid in food samples. The leading electrolyte contained hydrochloric acid (10 mmol/l), β-alanine (pH 3.0), and methylhydroxyethylcellulose (0.1%). The terminating electrolyte was 5 mmol/l caproic acid. The method is suitable for determining ascorbic acid in juice, beers, and as additives to meat products. The method was also applied for the determination of isoascorbic acid in additives to meat products. Received: 21 February 2000 / Revised version: 15 May 2000     

Flavour formation in meat and meat products: a review

The characteristic flavour of cooked meat derives from thermally induced reactions occurring during heating, principally the Maillard reaction and the degradation of lipid. Both types of reaction involve complex reaction pathways leading to a wide range of products, which account for the large number of volatile compounds found in cooked meat. Heterocyclic compounds, especially those containing sulfur, are important flavour compounds produced in the Maillard reaction providing savoury, meaty, roast and boiled flavours. Lipid degradation provides compounds which give fatty aromas to cooked meat and compounds which determine some of the aroma differences between meats from different species. Compounds formed during the Maillard reaction may also react with other components of meat, adding to the complexity of the profile of aroma compounds. For example, aldehydes and other carbonyls formed during lipid oxidation have been shown to react readily with Maillard intermediates. Such interactions give rise to additional aroma compounds, but they also modify the overall profile of compounds contributing to meat flavour. In particular, such interactions may control the formation of sulfur compounds, and other Maillard-derived volatiles, at levels which give the optimum cooked meat flavour characteristics.     

Effect of plant polyphenols and ascorbic acid on lipid oxidation,residual nitrite and N‐nitrosamines formation in dry‐cured sausage

The effects of green tea,grape seed polyphenols and ascorbic acid on pH, water activity (a_w), microbiological counts, TBARS, residual nitrite and N‐nitrosamines were determined in dry‐cured sausages during the ripening period. Results showed that TBARS increased gradually during ripening (P < 0.05), but were significantly reduced with plant polyphenols and ascorbic acid (P < 0.05). Green tea polyphenol (GTP) was most effective (P < 0.05) in reducing TBARS. Plant polyphenols and ascorbic acid significantly decreased residual nitrite, ascorbic acid being most effective (P < 0.05). The amount of N‐nitrosamines increased during ripening, but was significantly reduced with plant polyphenols and ascorbic acid (P < 0.05). Plant polyphenols had no significant effects on moisture content, a_w, pH or microbiological counts in dry‐cured sausage during ripening (P > 0.05). It was concluded that plant polyphenols and ascorbic acid were effective in maintaining the quality and safety of dry‐cured sausages.     

Measurement of ascorbic acid and erythorbic acid in processed meat by HPLC

Summary A simple and efficient HPLC method is described to measure both ascorbic and erythorbic acid separately in processed meat products. The system used consisted of a reversed-phase column, a mobile phase containing an ion-pairing agent and ultraviolet detection. The procedure, which was checked on a variety of samples, was found to give reproducible and reliable results.

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HPLC-Methode zur Bestimmung der Ascorbinsäure und der Erythorbinsäure in Fleischwaren

Zusammenfassung Eine einfache und effiziente HPLC-Methode wird beschrieben, welche die separate Bestimmung der Ascorbinsäure neben der Erythorbinsäure in Fleischwaren ermöglicht. Das System besteht aus einer Umkehrphasensäule, einer mit einem Ionenpaarbildner modulierten mobilen Phase und UV-Detektion. Das Verfahren wurde an einer Reihe verschiedener Proben getestet und erwies sich als zuverlässig und reproduzierbar.

     

Measurement of ascorbic acid and erythorbic acid in processed meat by HPLC

A simple and efficient HPLC method is described to measure both ascorbic and erythorbic acid separately in processed meat products. The system used consisted of a reversed-phase column, a mobile phase containing an ion-pairing agent and ultraviolet detection. The procedure, which was checked on a variety of samples, was found to give reproducible and reliable results.     

The effect of heat treatment on the cholesterol oxides,cholesterol, total lipid and fatty acid contents of processed meat products

The effects of heat treatment on the formation of cholesterol oxides and on alterations of fatty acid composition were investigated in processed meat products. Meatballs (beef), hamburger (beef and Chester), sausage (pork, chicken and Chester) and frankfurter (mixed meat, chicken and Chester) were analysed. There was no cholesterol oxide formation caused by heat treatment of the samples analysed. The fatty acid compositions, calculated as g/100 g sample, showed alterations only between the raw and grilled beef hamburger. Only the cholesterol levels were significantly changed when comparing the raw and grilled pork sausages and the raw and grilled Chester hamburger, the values being lower in the grilled samples. Also, the total lipid contents of grilled beef hamburgers were lower than the values.