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.     

Cholesterol oxide, cholesterol, total lipid and fatty acid contents in processed meat products during storage

The effects of storage time on the formation of cholesterol oxides and on alterations in the fatty acid composition of processed meat products manufactured by Brazilian industries were investigated in this study. Cholesterol oxides and cholesterol were determined by HPLC using photodiode array and refractive index detectors. Samples of jerked beef, Italian-type salami, chicken mortadella and Chester mortadella were analysed at 30 day intervals starting at zero time, for 90 days for the mortadella and 120 days for the jerked beef and salami. The mortadellas were stored under refrigeration at 6 °C and the jerked beef and salami at room temperature, but protected from the light. No cholesterol oxides were formed during the storage time in any of the samples. The cholesterol content, the fatty acid composition and total lipid contents showed no significant differences during storage with the exception of the total lipid content of the jerked beef, which varied from 3.5 at zero time to 2.4 g/100 g after 120 days storage.     

Automated turbidimetry for rapid determination of the bacteriological quality of raw meat and processed meat products

A fully automated centrifugal spectrophotometer for turbidimetric measurements linked to a computer for data processing was used to record and analyze growth of different types of bacteria associated with spoilage of raw meat and processed meat products (sliced meat for sandwiches) in order to predict bacterial counts. Media for this specific analysis were developed to enumerate total viable count, lactic acid bacteria. Brochothrix thermosphacta and Pseudomonas spp. Correlation coefficients of -0.91 to -0.97 were obtained between the conventional plate count technique and the turbidimetric method (linear regression). Lactic acid bacteria in the range 10(3) to 10(9) cfu/g could be detected within 48 h, whereas total viable count, Brochothrix thermosphacta and Pseudomonas spp. generally could be detected within 24 h. Counts exceeding 10(7) cfu/g could be detected within 6 h.     

Influence of turkey meat on residual nitrite in cured meat products

A response surface experimental design was employed to estimate residual nitrite level at various initial nitrite concentrations, percent turkey meat in the formula, and heat quantity (F) values using a typical wiener as the test system. Pork and mechanically separated turkey were used as the meat ingredients. Residual nitrite and pH were measured at day 1, 7 days, 14 days, and 49 days after processing. Protein, fat, salt, moisture, and CIE (L*a*b*) color values were also determined. Results showed that the effect of turkey meat on residual nitrite level was significant (P < 0.01). An increased amount of turkey meat in the formula resulted in lower residual nitrite levels at a fixed pH. The residual nitrite level was initially proportional to initial nitrite concentration, but it became a nonsignificant factor during longer storage time. Differences in heat quantity had a significant effect (P < 0.05) on residual nitrite level initially. Greater heat quantity decreased residual nitrite level in finished cured meat products at a fixed pH. However, this effect became nonsignificant during longer storage. Reduction of residual nitrite in wieners because of turkey meat addition at a fixed pH was due to characteristics of the turkey tissue, but the mechanism of action remains unknown. It was also established that commercial wieners had a higher pH if poultry meat was included in the formulation.     

抑制电导—离子色谱法同时测定肉制品中亚硝酸盐和硝酸盐

建立了一种灵敏、快速的同时测定肉制品中亚硝酸盐和硝酸盐的抑制电导-离子色谱分析方法。样品经超声提取后,以DIONEXIonPacAS19(4mm×250mm)色谱柱分离,用DIONEXEG40淋洗液发生器自动淋洗,采用梯度洗脱方式,以抑制电导检测器进行检测。实验表明,硝酸盐和亚硝酸盐的方法检出限(3S/N)为0.6mg/kg和0.8mg/kg,在0.1～50μg/mL范围内呈良好线性关系,相关系数分别为0.9994和0.9989,回收率为98.4%和96.5%,重复性(RSD)为2.8%和3.2%。本方法灵敏度高,重复性好,可用于肉制品中的亚硝酸盐和硝酸盐的检测。     

Thermophysical properties of processed meat and poultry products

Thermophysical properties of various meat and poultry emulsions were evaluated at four temperatures (20, 40, 60 and 80 °C). Thermal conductivities (0.26–0.48 W m⁻¹ K⁻¹) increased linearly with temperature between 20 and 60 °C. Between 60 and 80 °C, it remained constant for most products except bologna. Curves for thermal conductivity as a function of temperature could be roughly grouped into two different categories: products containing meat particles and those containing meat emulsions. The application of various models was investigated for thermal conductivity prediction. It was found that a three phase structural based Kirscher model had the potential for predicting thermal conductivities with acceptable accuracy. Densities decreased slightly as a function of temperature from 20 to 40 °C. A transition phase was observed from 40 to 60 °C, which was followed by a decrease from 60 to 80 °C. There was a decrease of about 50 kg m⁻³ between the density of a raw product at room temperature (at maximum 1070 kg m⁻³) and the product heated to 80 °C (at minimum 970 kg m⁻³), due to the gelation or setting of the structure. After a transition period from 10 to 30 °C, the heat capacity increased linearly from 30 to 80 °C, and ranged from 2850 to 3380 J kg⁻¹ °C⁻¹, respectively. Densities and heat capacities were strongly influenced by the carbohydrate content (i.e. as the carbohydrate content increased the density decreased). The salt content adversely affected thermal conductivity and thermal diffusivity values. However, these parameters increased with moisture content.     

Detection of allergenic additives in processed meat products

Allergic responses to food components are an increasing problem all over the world. It is therefore important to protect people who are vulnerable to food allergens against accidental and unintended consumption of products containing allergic ingredients. The meat industry commonly uses various allergic additives in the production of processed products, such as legumes (soy, peas, beans), milk and egg preparations, cereals containing gluten (wheat, rye, barley and oats), and spices (celery and mustard). These meat additives have specific technological properties, which help to create a texture or flavor profile, or affect the nutritional value, although some of them, such as soy, mustard, milk and egg white proteins, can cause severe allergic reactions. The aim of this paper is to discuss the application of various recently established methods of detection of allergenic additives in processed meat products – for instance cold cuts and sausages. The new methods are based mainly on protein, DNA, and isoflavones or phytic acid analysis. The article also characterizes the latest trends in the development of research on methods that would enable quick and reliable identification of targeted allergens in meat products. © 2018 Society of Chemical Industry     

Phytosterol oxides content in selected thermally processed products

Heat treatments are very popular methods of food preparation in European countries. Phytosterol present in foodstuffs undergoes oxidative changes during heat treatment, and phytosterol oxides (e.g., 7α-, 7β-hydroxysterol, 5α,6α-, 5β,6β-epoxysterol, 7-ketosterol and triol) are formed. Phytosterol oxidation products (POPs) have been associated with cytotoxic and pro-apoptotic effects in humans. On the other hand, several studies conducted on animals revealed that some phytosterol oxides lower serum triacyglycerol and blood glucose levels. The aim of this study was to evaluate the effect of heat treatment on formation of phytosterol oxidation products in selected foodstuffs. The following products were taken into considerations: minced meat (pork and beef), frozen French fries, frozen fish fillets, frozen fish products (e.g., fish sticks), wheat and egg noodles. Sterols and POPs content was evaluated by GC–MS working in total and selected ion monitoring modes. The phytosterol oxidation rate was higher in French fries and fish fillets (0.20–1.69% of total phytosterol content) than in noodles, minced meats and readymade fish products (in 0.04–0.36% range). Method of POPs determination using GC–MS is reported in this study. Results of this study show also that products of the animal origin might be considered as sources of the phytosterol oxides in the human diet.     

The determination of soya and meat protein in raw and processed meat products by specific peptide analysis. An evaluation

The detection and measurement of characteristic peptides formed on enzymatic hydrolysis of soya protein products, meats and offals is described. Samples were heated at 120°C for 3h prior to digestion with trypsin overnight, and the resultant peptide mixtures passed through an Amicon ultrafiltration membrane. After concentration the ultrafiltrates were analysed by ion exchange chromatography on Aminex A5 resin. Peptides were detected by post-column reaction with ninhydrin. Characteristic peaks designated SP 2 and MP 1 were seen in chromatograms of digests of soya protein isolate and beef respectively, and these peaks were well resolved in beef and soya protein isolate mixtures. The SP 2 peak was shown to contain peptides derived from soya 11 S globulin. The soya protein and beef contents of a series of mixtures of freeze-dried, defatted beef and soya protein isolate were determined by measurement of the SP 2 and MP 1 peaks respectively. Soya protein content could be determined within 2% of the true value over the range 30–70% soya protein isolate and beef content could be determined within 5% of the true value in the range 20–100% beef. Analysis of five soya protein isolates, four soya protein concentrates, six soya flours and 13 textured soya products indicated considerable interproduct variation in the yield of SP 2. The MP 1 peak was seen in a range of meats, both cooked and raw. It was also present in digests of offals which contained smooth or striated muscle but not in ‘non-muscle’ offals. The protein origin of the MP 1 peak was not established but the yield appeared lower in meat products which had been heated during manufacture than in those which had received no such treatment. Analysis of a series of laboratory prepared canned and heated pork and soya protein isolate mixtures enabled the pork content to be determined to within 8% of the true value, 2% soya protein isolate could be detected but not quantified accurately.     

Fatty acids, antioxidants and oxidation stability of processed reindeer meat

The effect of hot smoking and drying on reindeer meat (M. semimembranosus) was investigated with regard to vitamin content, fatty acids (FA), lipid oxidation and lipolysis. In smoked and dried meat, free fatty acids were found to increase (P<0.001), whereas polar lipids, cholesterol and triacylglycerols decreased. Only slight changes in FA composition of the smoked meat were found but the composition of the dried meat differed significantly from both smoked and fresh meat. Fresh and smoked meat were found to have low values (0.11 μg/g dry matter (DM); 0.21 μg/g DM) of thiobarbituric acid reacting substances but dried meat had high values (8.33 μg/g DM; P<0.001). Retinol was found only in the fresh meat and the tocopherol content decreased significantly (P<0.001) as a result of the processing. We conclude that the smoking process slightly changed FA composition, lipid class composition and vitamin content, whereas drying resulted in major changes in all the analysed parameters.     

高效液相色谱法同时检测肉制品中4种着色剂

目的建立高效液相色谱法检测肉制品中诱惑红、胭脂红、柠檬黄、日落黄的实验方法。方法采用氨水-乙醇溶液提取,用正己烷脱脂,对氨水乙醇提取液采用定量浓缩仪浓缩。利用液相色谱作为检测手段,紫外检测器分波段采集。结果在0~50.0μg/m L范围内线性良好,4种色素的相关系数均大于0.999,平均回收率为诱惑红78.6%,胭脂红79.2%,柠檬黄78.3%,日落黄79.6%。检出限均为1.0 mg/kg。结论该方法具有样品预处理简单、快速、灵敏度高等特点,可用于肉制品中诱惑红、胭脂红、柠檬黄、日落黄的同时检测。     

气相色谱法同时测定植物油脂中的脂肪酸和角鲨烯含量

目的 建立能准确快速并同时测定植物油脂中脂肪酸和角鲨烯含量的气相色谱方法。方法 植物油脂样品皂化酯化后,经正庚烷提取,气相色谱仪分析测定,脂肪酸采用面积归一化法定量,角鲨烯则用外标法定量。结果 37种脂肪酸和角鲨烯得到了良好分离,定性定量准确;角鲨烯在2～500 mg/L范围内具有较好的线性关系,相关系数为0.999 7;在三个添加水平下,样品中角鲨烯回收率在94.1%～104.6%之间,样品相对标准偏差为1.03%、1.24%,角鲨烯的定量限为4 mg/kg,脂肪酸定量限为0.001 3 g/100 g;选用花生油脂肪酸有证标物进行了脂肪酸验证试验,结果满足证书要求,且与国标前处理方法结果一致,相对误差小于2%。结论 本方法准确可靠、检测通量高、前处理操作简便、能耗低,可大大提高检测效率,降低检测成本。     

HPLC法测定不同产地火麻仁中五种脂肪酸含量

目的:采用高效液相色谱法对不同产地火麻仁药材中五种主要脂肪酸(α-亚麻酸、亚油酸、油酸、棕榈酸、硬脂酸)进行含量测定,据此对不同产地火麻仁的优劣进行评价。方法:采用Agilent EclipseXDB-C18色谱柱(150mm×4.6mm,5μm),以甲醇-水(85∶15)为流动相,流速1.0mL.min-1,检测波长210nm,柱温30℃。在此条件下,该五种脂肪酸的甲酯化产物与其他组分得到良好的分离,α-亚麻酸甲酯、亚油酸甲酯、油酸甲酯、棕榈酸甲酯和硬脂酸甲酯的进样量分别在42 168μg(r=0.9998)、67267μg(r=0.9995)、9.7 39μg(r=0.9995)、23 94μg(r=0.9996)和14 56μg(r=0.9997)范围内与各自峰面积积分值呈良好线性关系;平均加样回收率分别为99.5%(RSD=0.65%,n=6)、99.5%(RSD=1.20%,n=6)、99.2%(RSD=0.41%,n=6)、99.0%(RSD=0.60%,n=6)和99.5%(RSD=0.61%,n=6)。结论:该法操作简便,结果可靠。不同产地火麻仁油脂中的脂肪酸含量的确具有一定差异,以保定地区的脂肪酸含量为最高,可为火麻仁油脂的合理开发利用提供相关借鉴。     

N-Nitrosamines: a potential hazard in processed meat products

Nitrite, nitrate, and their salts are added to processed meat products to improve color, flavor, and shelf life and to lower the microbial burden. N-Nitrosamine compounds are formed when nitrosing agents (such as secondary nitrosamines) in meat products interact with nitrites and nitrates that have been added to the meat. With the consumption of such meat products, nitrosation reactions occur in the human body and N-nitrosamine formation occurs in the gastrointestinal tract. Despite the benefits nitrites and nitrates have on food, their tendency to create nitrosamines and an increase in the body's nitrous amine load presents health risks. The inclusion of nitrosamine compounds in possible and probable carcinogen classes according to the International Agency for Research on Cancer requires a re-examination of the literature review on processed meat products. This article evaluates the connections between various cancer types and nitrosamines found in processed meat products. © 2023 Society of Chemical Industry.     

离子色谱法同时测定果汁中低级脂肪酸

以邻苯二甲酸氢钾和邻苯二甲酸混合水溶液为淋洗液,用阴离子交换柱直接电导检测,建立了果汁中四种低级脂肪酸同时分析的方法,考察了影响分离的因素。当邻苯二甲酸氢钾和邻苯二甲酸的浓度分别为0.75mmol/L和0.5mmol/L(pH=3.97)时,分离效果良好,各组分的相对标准偏差均在1.4%～2.8%之间。     

GC法同时测定火麻仁油中5种脂肪酸类成分的含量

建立同时测定火麻仁油中棕榈酸、硬脂酸、油酸、亚油酸和亚麻酸含量的方法。采用气相色谱法,色谱柱为DB-WAX弹性石英毛细管柱,检测器为氢火焰离子化检测器,以氮气为载气,采用程序升温,内标法测定含量,对线性范围、精密度、回收率等指标进行了考察。结果表明,该方法测定火麻仁油中脂肪酸的含量快速、准确、重复性好,可为火麻仁油的质量控制提供参考。     

正相高效液相色谱法同时测定腌腊肉制品中13-HODE和9-HODE含量

采用高效液相色谱对腌腊肉制品中的13-羟基十八碳二烯酸（13-HODE）和9-羟基十八碳二烯酸（9-HODE）进行检测。腌腊肉制品中的13-HODE和9-HODE用甲醇提取,经C18固相萃取柱净化,以正己烷/异丙醇/乙酸（98∶2∶0.5,v/v/v）为流动相,在Lichrosorb Si 60（250×4.0 mm,5μm）色谱柱上分离,选用二极管阵列检测器在234 nm进行检测。结果表明:13-HODE和9-HODE分别在0.5²0和1.0¹2.5μg/m L范围内线性良好（R²分别为0.9994和0.9990）,检测限分别为0.075、0.15μg/g,定量限分别为0.25、0.5μg/g。不同添加水平的平均回收率分别为88.2%和86.0%。对14种腌腊肉制品的分析结果显示,所有样本均含有13-HODE和9-HODE,范围分别为:1.2¹67.54和0.63¹39.20μg/g。本实验建立的检测方法操作简单、易于普及,具有良好的灵敏度和准确性,可以满足腌腊肉制品中13-HODE和9-HODE含量的同时分析。      

气相色谱-串联质谱法同时测定肉制品中氯霉素、甲砜霉素残留

建立了肉制品中氯霉素、甲砜霉素的气相色谱串联质谱检测方法。样品经均质后,用乙酸乙酯提取,正己烷脱脂,弗罗里硅土小柱净化,衍生后用气相色谱串联质谱法检测,内标法定量。优化了二级质谱条件,包括离子对及碰撞电压。该方法检出限为氯霉素(CAP)0.02μg/kg,甲砜霉素(TAP)0.1μg/kg,加标回收率均在86%~97%之间,相对标准偏差(RSD)在3.8%~12.3%之间,在0.1~20 ng/mL范围内都呈现出良好线性关系。     

加工肉制品中杂环胺的研究进展

杂环胺(heterocyclic amines,HAs)是一类致癌致突变的多环芳香族化合物,通常在肉类等富含蛋白质的食品原料的热处理过程中产生,能通过其环外游离氨基与DNA反应生成加合物而产生致癌致突变毒性。当前,肉类产品加工过程中杂环胺的生成及控制已逐渐成为食品安全领域研究的热点。本文阐述了杂环胺的结构、分类和生物毒性,探讨分析了肉制品加工过程中杂环胺的形成路径和机制,总结了近年来杂环胺抑制方法的研究进展,并对利用模拟体系与先进检测技术探索杂环胺形成机制的研究进行了展望。