采用离子色谱检测肉及肉制品中多聚磷酸盐

采用离子色谱技术同时检测肉及肉制品中的正磷酸盐、焦磷酸盐、三聚磷酸盐和三偏磷酸盐成分。对建立的方法进行检出限、定量限和最佳线性范围的确定,并进行加标回收和精密度测定,以及实际应用效果评价。4种磷酸盐分离度良好,正磷酸盐、焦磷酸盐、三聚磷酸盐、三偏磷酸盐检出限分别为0.01、0.15、0.15、0.15mg/L,定量限分别为0.05、0.5、0.5、0.5 mg/L,分别在0.05~200、0.2~200、0.2~200、0.2~200 mg/L浓度内,呈良好线性关系。在3个浓度水平加标,其中正磷酸盐1 000、2 000、5 000 mg/kg,焦磷酸盐、三聚磷酸盐和三偏磷酸盐50、100、200 mg/kg,加标回收率为83.2%~101.9%,相对标准偏差(relative standard deviation,RSD)小于2.02%。用建立的方法对市售产品进行检测分析,结果可以满足市售肉及肉制品样品的检测需求。     

低盐肉制品降盐与品质改良加工技术研究进展

肉制品是人类重要的营养物质来源,在肉制品加工过程中食盐是常见且必需的调味料。传统加工肉制品普遍含盐量过高,过量的摄入食盐也已经被证实能引发一系列的心脑血管疾病,因此开发低盐肉制品势在必行。但是,直接减少食盐添加量会对产品风味、口感、质构和保质期产生不利影响。因此,需要通过添加风味提升物、品质改良剂等物质并辅助以品质改良加工技术来优化产品品质。本文论述了国内外低盐肉制品的研究现状,阐述了降盐技术(食盐替代物、改变食盐形态等)和品质改良加工技术(腌制技术、超声波技术、超高压技术等)在肉制品中应用研究进展,指出其研发中存在的主要问题,并对其未来的发展前景进行展望,为低盐肉制品研发提供理论借鉴和参考。     

离子色谱法测定肉及肉制品中多聚磷酸盐的研究进展

多聚磷酸盐是肉及肉制品中常用的品质改良剂,但摄入过量的磷酸盐也会危害人体健康。离子色谱由于具有可对不同形态的多聚磷酸盐同时进行分离测定的优点,目前研究较多,然而多聚磷酸盐在肉制品中的分解给多聚磷酸盐的准确测定带来困扰。本文主要介绍了近年来国内应用离子色谱法测定肉及肉制品中多聚磷酸盐的研究成果,对于准确、快速选择适于实际样品测定的方法具有一定意义。     

Evaluation of salt, polyphosphates and their blends at different levels on physicochemical properties of buffalo meat and patties

The effects of sodium pyrophosphate (SPP), sodium tripolyphosphate (STPP), sodium hexametaphosphate (SHMP), sodium acid pyrophosphate (SAPP) and their blends at different levels (0·3, 0·5 and 0·7%), along with 2% sodium chloride on certain quality parameters of buffalo meat and patties were evaluated. The SPP, STPP and phosphate blends significantly increased pH, water-holding capacity (WHC), emulsifying capacity (EC), extractability of salt soluble proteins (SSP), colour of ground meat, decreased cooking loss (CL), improved emulsion stability (ES) and enhanced yield, texture and moisture retention of cooked patties. Compared to these phosphates, SAPP and SHMP had significantly poorer effects on improving the quality of meat and patties. The order of effectiveness of phosphates was SPP > STPP > SHMP. In general, pH, WHC, SSP, ES, yield and moisture content of patties increased progressively with increasing level of phosphate while CL decreased. Among blends containing two polyphosphates, those of 90% SPP + 10% SHMP and 75% SPP + 25% STPP were relatively more effective. A phosphate blend consisting of 65% SPP, 17·5% STPP and 17·5% SAPP was equally effective as that of SPP in improving the functionality of hot and chilled meat and had the advantage of reducing the amount of sodium by 3%.     

Contribution of major structural changes in myofibrils to rabbit meat tenderisation during ageing

The contribution of major structural (myofibrillar fragmentation upon mechanical treatment) and ultra-structural (Z-line degradation, loss of electron density of M-line, transversal disruption of sarcomeres at N(2)-line level, longitudinal fissure of myofibrils, and loss of transversal alignments of Z- and M-lines) changes in myofibrils to rabbit (Oryctolagus cuniculus L.) meat tenderisation, during the ageing period (9 days at +4?°C), was studied for different types of muscle (type I, semimembranosus proprius; type IIB, semimembranosus accessorius; and type IID, psoas major). The results strongly suggest that myofibrillar structure weakening at N(2)-line level (evaluated by myofibrillar fragmentation upon mechanical homogenisation and observed by transversal disruption of sarcomeres), which is very likely mediated by cysteine endopeptidases, might be the major structural change responsible for rabbit meat tenderisation during ageing. Both myofibrillar fragmentation and transversal disruption of sarcomeres are good ageing indices for rabbit meat. The other major ultra-structural changes in myofibrils appear to have no major role in rabbit meat tenderisation at refrigeration temperatures. Finally, it is proposed that meat tenderisation during ageing depends mainly on the specific cleavage of titin molecules/filaments and nebulin molecules, at their susceptible sites located at or very close to the N(2)-line region (extensible segment and near C-terminus, respectively), mediated by cysteine endopeptidases (possibly calpains).     

Effects of polyphosphates on reactions of metmyoglobin related to oxidative changes in meat products

Summary Diphosphate, triphosphate and trimetaphosphate stabilize the haem cavity in metmyoglobin (MMb), as evidenced by an absorption increase in the Soret band, while only triphosphate and trimetaphosphate decrease the rate of MMb-catalysed oxidation of linoleic acid as monitored by oxygen consumption. It is suggested that the larger triphosphate and trimetaphosphate most effectively hamper access of lipid substrates to the iron (III) in the haem cavity, protecting both the MMb and to a lesser extent the fatty acid against oxidative degradation. Further indication of a weak but specific interaction between the polyphosphates and the haem cavity of MMb was found in an increase in the rate of enzymatic reduction of MMb to oxymyoglobin, most significantly by trimetaphosphate, and in a lowering of the acidity of the water co-ordinated to iron (III) in MMb (pK_a=8.83 with added polyphosphates, and pK_a=8.52 without added polyphosphates, 25° C, extrapolated to zero ionic strength).

---

Die Einflüsse von Polyphosphaten auf die Reaktionen von Metmyoglobin in Relation zu oxidativen Veränderungen in Fleischprodukten

Zusammenfassung Diphosphate als auch Triphosphate und Trimetaphosphate stabilisieren den Häm-Hohlraum von Metmyoglobin (MMb), wie eine erhöhte Absorption der Soret-Bande zeigt, obwohl nur Triphosphate und Trimetaphosphate die MMb katalysierte Oxidationsgeschwindigkeit von Linolsäure reduzieren, wie durch den Sauerstoffverbrauch überprüft wurde. Wir behaupten, daß die größeren Triphosphate und Trimetaphosphate den Zugang des Lipidsubstrates zum Eisen (III) in den Häm-Hohlraum behindern und sowohl das MMb als auch in geringerem Umfang die Fettsäure gegen oxidati ven Abbau schützen. Ein weiterer Hinweis für eine schwache, aber spezifische Wechselwirkung zwischen Polyphosphaten und dem Häm-Hohlraum des MMb wurde festgestellt, durch eine Erhöhung der enzymatischen Reduktionsgeschwindigkeit von MMb zu Oxymyoglobin, am stärksten durch Trimetaphosphate und durch eine Reduktion der Acidität des in MMb koordinierten Wassers an Eisen (III) (pK_a=8.83 mit Polyphosphaten und pK_a=8.52 ohne Polyphosphate bei 25 °C, extrapoliert auf Ionenstärke Null).

     

On the mechanism of water holding in meat: The swelling and shrinking of myofibrils

Water holding in meat has, in the past, been rather poorly understood and has not been explained at all in structural terms. A unifying hypothesis for this phenomenon is that gains or losses of water in meat are due simply to swelling or shrinking of the myofibrils caused by expansion or shrinking of the filament lattice.

Myofibrils have been observed by phase contrast microscopy, and are seen to swell quickly to about twice their original volume in salt solutions resembling those used in meat processing. Such swelling is highly co-operative. Pyrophosphate reduces very substantially the sodium chloride concentration required for maximum swelling. In the absence of pyrophosphate, swelling is accompanied by extraction of the middle of the A-band; in its presence the A-band is completely extracted, beginning from its ends.

We suppose that Cl⁻ ions bind to the filaments and increase the electrostatic repulsive force between them. A crucial factor in swelling is likely to be the removal at a critical salt concentration of one or more transverse structural constraints in the myofibril (probably crossbridges, the M-line or the Z-line) allowing the filament lattice to expand.

We also point out that water losses in rigor, in the PSE condition and on cooking may well result directly from shrinkage of the filament lattice.     

蚌肉盐溶蛋白提取工艺优化及其功能特性研究

以盐溶蛋白得率为指标对蚌肉盐溶蛋白的提取条件进行了优化,并对其主要功能特性进行了测定。结果表明:Na Cl浓度为0.7 mol/L、p H值为7、浸提时间为24 h、固液比为1∶4时,河蚌盐溶蛋白提取量最大,可达117mg/g。蚌肉盐溶蛋白的持水性和持油性分别为3.0 g/g和2.2 g/g;在p H值为8时,其溶解性为38%;最佳起泡能力和泡沫稳定性分别为71%和24%;其乳化能力受蛋白浓度变化的影响不大;蛋白浓度为1.0%时,其凝胶保水性可达到74%。将蚌肉盐溶蛋白替代大豆蛋白添加到西式香肠中,产品的外观、风味、肉质等品质均无明显区别,是一种较好的功能性蛋白质资源。     

A modified hot processing strategy for beef: functionality of electrically-stimulated and hot-boned meat preblended with different NaCl concentrations

Chucks from 20 electrically-stimulated hot-boned (HB) and cold-boned (CB) beef carcasses were preblended with different concentrations of NaCl (0, 0·5, 1·0, 1·5 and 2·0% w/w). Preblends were analysed for pH, 2-thiobarbituric acid (TBA) values, protein extraction and emulsifying capacities. Bologna (with and without added sodium tripolyphosphate) and ground meat patties prepared from these preblends were also evaluated for cooking yield, color and texture parameters. Ultimate pH values of HB preblends increased with increasing NaCl concentration. At 1% NaCl, HB had higher ultimate pH than CB preblends (P ≤ 0·05) but preblending HB meat with 2% NaCl reduced TBA values (P ≤ 0·05) because the pH was maintained above 6·0. Higher amounts of protein were extracted from HB than from CB preblends (P ≤ 0·01), but boning and salting treatments did not affect their emulsifying capacities (P > 0·05). Two percent NaCl was required to fully achieve the prerigor salting effect. At this concentration, cooking yields of bologna prepared from HB preblends and phosphate containing bologna prepared from CB preblends were not different (P > 0·05) and were higher than those of bologna without added phosphate made from CB preblends (P ≤ 0·05). No meaningful effects were observed on color and texture parameters. Cooking losses were lower in patties made from HB than CB preblends (P ≤ 0·05) independent of NaCl concentration, but boning and salting treatments had no further effects on color or textural parameters (P > 0·05). Therefore, the superior functional properties of electrically stimulated prerigor meat can be maintained by the addition of 2% NaCl up to 2 h post-mortem.     

Fragmentation of myofibrils, limited proteolysis and water holding capacity of meat

Protein changes in ageing meat result in increased vulnerability of the myofibrils to fragmentation, caused possibly by limited proteolysis. It was investigated which groups of muscle proteases, if any, were involved and what was the relation between fragmentation and hydration of beef meat. In samples ranging in natural pH from 5.4 to 7.0 the least fragmentation after 3 days at 2 degrees C was at pH 6. This could suggest the role of both the cathepsins and neutral proteases. In samples aged in the presence of EDTA fragmentation was significantly lower than in the controls. This could indicate the role of Ca2+ activated neutral proteases, or support the hypothesis on the nonenzymatic mechanism involving Ca2+. The results of PAG electrophoresis could not have been due to the neutral proteases, as the 30,000 g X mol-1 component, resulting from the hydrolysis of troponin T, did not accumulate at pH 7 until the 9th day of ageing, but at pH 5.4 the intensity of this band increased markedly already after 3 days. There was no correlation between the fragmentation and the hydration of the aged meat after cooking. The addition of 0.001% of trypsin or 0.0005% of papain to minced meat did not cause after 9 days any increase in the contents of free amino acids and peptides or significant changes in the PAGE pattern as compared to those in the controls. However, the fragmentation and hydration of the raw meat was larger in the samples containing added enzymes. After cooking the hydration of the samples did not differ.(ABSTRACT TRUNCATED AT 250 WORDS)     

维生素E在肉类加工中的应用

维生素是调节人体新陈代谢,维持机体生命和健康必不可缺少的元素。它不能在人体内合成,需从外界摄入,以满足人体的需要。本文将就维生素E对人体的功能及其在肉食加工中的应用作简单介绍。     

Diffusivities of volatiles in concentrated solutions

Concentration profiles obtained by slicing a cylindrical gel were used to measure diffusion of volatiles in viscous aqueous dextrose solutions. The column length, slice thickness and diffusion time were optimized to maximize the repeatability of measurements, the results being very sensitive to small changes in variables. Coefficients of variation between 5 and 10% were obtained. In the presence of different concentrations of dextrose, the diffusivity of acetone decreased markedly as dextrose concentration increased. However, when the acetone concentration was varied within the range 0·6 to 13·7%, at a constant 50% (w/w) dextrose concentration, its diffusivity did not change significantly. The sliced gel system gave values of diffusivity in close agreement with those obtained by other techniques.     

Advances in ingredient and processing systems for meat and meat products

Changes in consumer demand of meat products as well as increased global competition are causing an unprecedented spur in processing and ingredient system developments within the meat manufacturing sector. Consumers demand healthier meat products that are low in salt, fat, cholesterol, nitrites and calories in general and contain in addition health-promoting bioactive components such as for example carotenoids, unsaturated fatty acids, sterols, and fibers. On the other hand, consumers expect these novel meat products with altered formulations to taste, look and smell the same way as their traditionally formulated and processed counterparts. At the same time, competition is forcing the meat processing industry to use the increasingly expensive raw material “meat” more efficiently and produce products at lower costs. With these changes in mind, this article presents a review of novel ingredient systems and processing approaches that are emerging to create high quality, affordable meat products not only in batch mode but also in large-scale continuous processes. Fat replacers, fat profile modification and cholesterol reduction techniques, new texture modifiers and alternative antioxidant and antimicrobial systems are being discussed. Modern processing equipment to establish continuously operating product manufacturing lines and that allow new meat product structures to be created and novel ingredients to be effectively utilized including vacuum fillers, grinders and fine dispersers, and slicers is reviewed in the context of structure creation in meat products. Finally, trends in future developments of ingredient and processing systems for meat products are highlighted.     

午餐肉中食盐含量的测定

采用直接沉淀滴定法测定午餐肉中的食盐含量,结果表明,所测样品中食盐含量为1.36g/100g,该方法简单、快速、准确度高,适用于午餐肉中食盐含量的测定。     

高压水冲击波加工在改善肉类品质方面的应用

HDP(Hydrodynamic pressure processing)技术是一项用于改善肉品嫩度、提高肉品安全性、延长肉品货架期的新兴技术。HDP技术通过使肌肉结构物理性断裂从而使肉得到嫩化,并且它作为一种非热处理可杀死肉中非致病细菌,降低肉中微生物菌落数,从而延长肉品的货架期。     

Origin of variable extraction of myosin from myofibrils treated with salt and pyrophosphate

When isolated myofibrils are treated with solutions containing NaCl and pyrophosphate to imitate conditions in meat being cured, considerable dijfirences are observed between myofibrils in the concentration of NaCl required for extraction of the myosin-containing A-band. The diferences in extent of extraction at an intermediate concentration of NaCl are between bundles of myofibrils rather than within them, indicating that the variation derives from differences between muscle fibres. The extraction behaviour is determined by the myosin isoenzyme content of the muscle fibre. Thus, the proportion of myofibrils extracted at an intermediate concentration of NaCl in preparations from various bovine and rabbit muscles reflects the documented proportion of fast-contracting fibres in each muscle. Rabbit M plantaris myofibrils from fast white fibres are extracted in a low concentration of NaCl, whereas those myofibrils containing slow myosin are extracted only in a high Concentration of NaCl. Myofibrils probably from fast red fibres require an intermediate concentration of NaCl for extraction.     

卡拉胶在肉制品中的应用

<正> 卡拉胶是一种天然的聚合物,是通过水萃取法从一些红海藻中提取而得的。基本上,卡拉胶可分为K-型、I-型和λ-型三种,是配制肉类产品的重要成分,能作为产品组织和加工的辅助剂,提高制成品的价值。本文先简述K-型和I-型卡拉胶在肉制品中的应用特性,再介绍新开发的卡拉胶在肉食品加工中的应用。     

提高产品质量 降低生产成本——谈谈卡拉胶在肉制品中的应用

卡拉胶萃取自红海藻,是一种可溶于水的天然增稠剂和胶凝剂,基本上可分为3种类型: 1.κ-型卡拉胶:会形成热可逆转的脆性凝胶; 2.ι-型卡拉胶:会形成热可逆转和触变的弹性凝胶; 3.λ-型卡拉胶:只能增稠,不会形成凝胶。 将这3种卡拉胶结合使用于备种肉禽制品中,既能提高产品的产出率,降低生产成本,又能提高产品的质量,提高整体的生产效益。