不同包装气氛条件和天然抗氧化剂对切块干腌火腿抗氧化效果的影响

采用真空气调包装和茶多酚、迷迭香等及其复合天然抗氧化剂对切块干腌火腿进行抗氧化处理,通过正交试验研究不同气氛条件、抗氧化剂及贮藏温度和时间对干腌火腿抗氧化的影响效果.结果表明:真空包装的过氧化值(POV)显著低于气调包装组(p<0.01);迷迭香+VE复合抗氧化效果最好(p<0.01),含茶多酚的复合抗氧化剂对维持火腿肌肉的红度值具有显著效果(p<0.05);酸价(AV)与贮藏温度呈正相关;AV、POV、TBARs值随着贮藏时间的延长显著上升(p<0.01),红度a*值显著下降(p<0.01),贮藏时间达到3个月,包装切块火腿POV超过国家限量指标(0.25g/100g);正交优化结果:采用0.05%迷迭香+0.05%VE喷淋切块火腿、真空包装、5℃贮藏2个月;实验结果与感官评定具有良好的一致性.     

切块火腿综合抗氧化及包装方法

对传统发酵成熟金华火腿切块,表面喷淋复合天然抗氧化剂、涂抹壳聚糖、并加入专用脱氧剂进行真空包装,分析测定在室温条件下从3月到9月储藏6个月时切块火腿的过氧化值(POV)、TBARs值和色差值,研究综合抗氧化包装处理对切块火腿品质的影响。结果表明:切块火腿经喷淋0.05%迷迭香+0.05%VE天然抗氧化剂、涂抹2.5%壳聚糖、加入含Fe量为2.0g脱氧剂真空包装的抗氧化包装处理,从春季到秋季室温贮藏6个月后,其肌肉的POV值和TBARs值分别为3.15meq/kg和0.27mg/kg,显著低于对照组(P<0.05),且在国家标准和国际认可的限量范围内(POV<19.7meq/kg,TBARs<1mg/kg),同时保持较好的感官颜色。     

天然抗氧化剂替代部分亚硝酸钠对乳化肠护色及抗氧化效果的影响

将迷迭香提取物、茶多酚、留兰香提取物、竹叶提取物及甘草提取物添加到乳化肠中,替代部分亚硝酸钠,研究其对乳化肠色泽稳定性和抗氧化性的影响。结果表明:与空白对照组相比,天然抗氧化剂的添加促进了亚硝酸钠的发色,延缓了乳化肠红度值(a*)的降低,降低了乳化肠的脂肪氧化程度。与0.010%的亚硝酸钠相比,竹叶提取物的护色作用较强,且添加量为0.030%时乳化肠的a*最大;留兰香提取物与茶多酚的护色效果次之,添加量分别为0.040%和0.024%时乳化肠的a*最大;迷迭香提取物与甘草提取物的护色效果最弱。与0.020%异抗坏血酸钠相比,茶多酚与竹叶提取物的抗氧化活性较强,它们的添加量为0.030%时表现出较好的抗氧化活性;迷迭香提取物与留兰香提取物的抗氧化效果次之,它们的添加量分别为0.030%和0.040%时具有较强的抗氧化活性;甘草提取物的抗氧化活性最弱。天然抗氧化剂对乳化肠中脂肪氧化的抑制作用与其对色泽的保护作用有着良好的对应关系,整体而言,竹叶提取物的护色及抗氧化效果最佳。     

茶多酚和鼠尾草对猪肉的抗氧化效果

比较研究茶多酚和鼠尾草对猪肉的抗氧化效果.通过改进猪肉过氧化值(POV值)和硫代巴比妥酸值(TBA值)的测定方法,分析分别添加茶多酚(1.0%)和鼠尾草(1.0%)的猪肉在5℃下贮藏10d(0d,2d,4d,6d,8d,10d)期间的脂肪氧化程度,同时对样品进行感官评定.结果表明:1.0%茶多酚处理组的POV值显著高于时照组(P<0.05),1.0%鼠尾草处理组的POV值极显著低于对照组(P<0.01);在前4天内各组间TBA值差异不显著(P>0.05),1.0%茶多酚处理组的TBA值在第6天及以后显著低于时照组(P<0.05),1.0%鼠尾草处理组的TBA值从第4天以后显著低于1.0%茶多酚处理组(P<0.05).第10天时,各组感官评定(气味、颜色、状态)总分为:1.0%鼠尾草处理组>1.0%茶多酚处理组>对照组.以上结果表明鼠尾草对猪肉的抗氧化效果明显优于茶多酚.     

迷迭香在油香椿制品储藏过程中的抗氧化效果研究

选用TBHQ、迷迭香和茶多酚等作为抗氧化材料,研究几种抗氧化剂对油香椿制品储藏过程中油脂氧化效果的影响.采用烘箱加热进行加速试验,定期测定油脂过氧化值(POV)的变化情况来研究不同浓度天然抗氧化剂迷迭香和添加维生素C、植酸或柠檬酸等增效剂的迷迭香抗氧化效果.实验结果显示:天然抗氧化剂迷迭香的抗氧化效果优于茶多酚,比TBHQ的抗氧化效果稍差,0.02%迷迭香能有效阻遏油脂中POV值的升高,它与维生素C、植酸或柠檬酸混合使用,能显著增强抗氧化作用.     

葡萄籽提取物对火腿发酵成熟过程脂质氧化的影响

脂质分解氧化是干腌火腿工艺过程中一个主要的生化反应过程,对干腌火腿风味形成具有十分重要的作用,但脂质过度氧化对火腿品质安全也会产生重大影响.本文采用天然抗氧化剂-葡萄籽提取物对传统发酵工艺火腿进行抗氧化处理,研究其对火腿脂质的抗氧化效果.结果显示:抗氧化处理组在发酵成熟时期能有效抑制火腿脂质氧化.成熟结束时,经葡萄籽提取物(GSE)抗氧化处理的火腿半膜肌过氧化值(POV)、TBA值、羰基值和双烯值分别比对照组降低了57%、48%、29%、18%;表层脂肪降低了60%、24%、42%、36%;而经葡萄籽提取物和猪油联合处理的火腿(GSE+Lard)半膜肌各氧化指标分别比对照组降低了20%、8%、14%、6%;表层脂肪降低了27%、5%、25%、24%.GSE处理组抗氧化效果优于GSE+Lard处理组.     

几种抗氧化剂对棉籽油氧化稳定性的影响

利用Rancimat法研究3种天然抗氧化剂迷迭香提取物、茶多酚、维生素E(VE)及合成抗氧化剂特丁基对苯二酚(TBHQ)对棉籽油抗氧化性能的影响.通过在棉籽油样品中添加不同质量浓度的单一和复合配比的抗氧化剂,分别测定诱导时间并考察抗氧化效果.结果表明,在棉籽油中单一抗氧化剂的抗氧化性能依次为TBHQ＞迷迭香＞茶多酚＞VE;在复合抗氧化剂组合中,迷迭香提取物与茶多酚以3∶1进行复配时具良好的协同增效作用;当3种天然抗氧化剂与TBHQ进行复配时,其抗氧化效果优于同等质量浓度的单一天然抗氧化剂.     

抗氧化剂在青刺果油贮藏稳定性中的应用研究

以青刺果油为试材,采用Schaal烘箱法,以过氧化值(POV)为指标,研究了4种抗氧化剂(迷迭香提取物、维生素E、茶多酚棕榈酸酯、抗坏血酸棕榈酸酯)、2种增效剂(维生素C、柠檬酸)及其复配后对青刺果油贮藏稳定性的影响,并与TBHQ作对比。结果表明:4种抗氧化剂对青刺果油的抗氧化强弱顺序为迷迭香提取物茶多酚棕榈酸酯抗坏血酸棕榈酸酯维生素E;维生素C、柠檬酸对迷迭香提取物、迷迭香提取物+茶多酚棕榈酸酯的抗氧化性能均有一定的协同增效作用,且柠檬酸的协同效果强于维生素C;单一抗氧化剂迷迭香提取物及其各复配抗氧化剂对青刺果油的抗氧化性能均优于TBHQ;添加0.04%迷迭香提取物+0.02%茶多酚棕榈酸酯+0.02%柠檬酸的青刺果油贮藏稳定性最高,可使青刺果油在25℃条件下的货架期由128 d延长至784 d。     

天然护色剂对酱牛肉护色效果的研究

针对于用红曲红色素作为表面着色剂的小包装方便酱卤肉制品在贮藏期间易发生氧化褪色这一现象,通过测定贮藏过程中酱牛肉的pH、红度值、色素残留率、感官评价,研究抗坏血酸钠、葡萄糖、茶多酚及其复合剂作为抗氧化剂对产品表面红曲红色素的保护效果。研究表明:0.05%的茶多酚护色效果最为显著,0.06%的抗坏血酸钠和0.01%的葡萄糖也明显起到了护色的效用,复合剂的相乘效用使其比单一组抗氧化效果更明显,且与市售护色剂间存在明显差异性(P<0.05)。复配护色剂(0.06%抗坏血酸钠+0.01%葡萄糖+0.05%茶多酚)能使酱牛肉储存28d后,红度值仍能达到12.51、色素残留率达到46.54%、感官评价达到3.5分,与对照组差异显著(P<0.05)。     

VE复合抗氧化剂在猪油中的抗氧化性能研究

以VE,VE分别与茶多酚、迷迭香、硫辛酸、槲皮素的复合物为抗氧化剂,添加到猪油中,比对其抗氧化性能。结果表明:VE、茶多酚、迷迭香、硫辛酸、槲皮素都具有一定的抗氧化效果,相同添加量的情况下单品的抗氧化能力大小顺序为:槲皮素>茶多酚>迷迭香>硫辛酸>VE;VE与四种天然的抗氧化剂1∶1进行复合以后与单一的抗氧化剂相比都具有一定的增效作用。     

Mineral contents of some southern Italian wines. II. Determination of Li, Na, Mg, K, Ca, Co, As, Rb, Sr, Ag, Sb, Ba

Following our study of the mineral contents of some Southern Italian wines, this work reports on the detection of 12 elemental components. The elements were determined using ICP-AES, flame atomic emission or absorption spectroscopy. The values determined for Li, Na, Mg, K, Ca, Rb, Sr and Ba were within the usual ranges for wines (average values for these elements were: 0.010, 26.2; 94.4; 888; 94.0; 3.30, 0.82 and 0.11 mg/l respectively). All the wines contained low levels of As, the concentrations of which were always under 0.20 mg/l, the maximum level permitted by E.E.C. standards. The measuring of Co, Ag, and Sb led us to ascertain, in all the wines, concentrations lower than 0.01 mg/l for Co and Ag and below the instrumental detection level for Sb (0.06 mg/l). In a previous study wines from D.O.C. areas of Southern Italy were analysed by the technique of inductively coupled plasma atomic emission spectroscopy (ICP-AES), for 14 minerals. This paper deals with further investigation of the mineral composition of the same wines for different metal constituents, analysed by ICP-AES, flame atomic emission, or atomic-absorption spectroscopy (two techniques). The first technique was applied to the detection of Co, As, Sr, Ag, Sb, and Ba. The alkaline metals Li, Na, K, and Rb were determined by flame atomic emission, a technique which possesses better detection limits for these elements. For Mg and Ca the atomic absorption methods were applied.     

Isolation,Composition, Structure,Properties, Modifications,and Uses of Yam Starch

Starch is the major carbohydrate in yam tubers and can amount up to 80% of the dry matter. The starch quality determines the quality of food and industrial products made from yam tubers. This review summarizes the present knowledge of the isolation, composition, structure, property, modifications, and uses of starches from diverse yam species. Compared with other tuber and root starches, there is a lack of systematic information on the yam starches. This hinders the further development of yams as sustainable crops as well as the value‐added processing of the starches. Therefore, suggestions on how to better understand and utilize these starches are provided.     

Survey of trace elements (Al,As, Cd,Cr, Co,Hg, Mn,Ni, Pb,Se, and Si) in retail samples of flavoured and bottled waters

Concentrations of eleven trace elements (Al, As, Cd, Cr, Co, Hg, Mn, Ni, Pb, Se, and Si) were measured in 39 (natural and flavoured) water samples. Determinations were performed using graphite furnace electrothermetry for almost all elements (Al, As, Cd, Cr, Co, Mn, Ni, Pb, and Si). For Se determination hydride generation was used, and cold vapour generation for Hg. These techniques were coupled to atomic absorption spectrophotometry. The trace element content of still or sparkling natural waters changed from brand to brand. Significant differences between natural still and natural sparkling waters (p < 0.001) were only apparent for Mn. The Mann–Whitney U-test was used to search for significant differences between flavoured and natural waters. The concentration of each element was compared with the presence of flavours, preservatives, acidifying agents, fruit juice and/or sweeteners, according to the labelled composition. It was shown that flavoured waters generally increase the trace element content. The addition of preservatives and acidifying regulators had a significant influence on Mn, Co, As and Si contents (p < 0.05). Fruit juice can also be correlated to the increase of Co and As. Sweeteners did not provide any significant difference in Mn, Co, Se and Si content.     

Analysis of cheese for histamine, tyramine, tryptamine, histidine, tyrosine, and tryptophane

A method is described for determining the content of selected biologically active amines (histamine, tyramine, tryptamine) and amino acids (histidine, tyrosine, tryptophane) in cheeses by high performance liquid chromatography. The amines and amino acids were quantified by employing a counter ion-containing mobile phase and by comparing peak areas of high performance liquid chromatography charts for sample cheeses versus standard cheeses containing known amounts of added amines based on dual injections of samples and standards. Recovery of amines and amino acids varied from 87.5 to 111%. Histamine, which has been associated with food poisoning in concentrations of 185 mg/100 g in Swiss cheese and 180 to 500 mg/100 g in fish, was found in concentrations above 500 mg/100 g in Swiss cheese. The high performance liquid chromatography analytical method should be useful for screening to detect cheese samples containing toxic amounts of histamine and for research studies designed to determine the cause and effect relationships for histamine production in cheese.     

卷烟中锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量分析

采用微波消解-电感耦合等离子体质谱法测定了41个牌号烤烟型卷烟和雪茄烟样品烟丝中的锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量,并按照类型和价位对卷烟中这10种有害元素含量进行了统计分析。结果发现:①卷烟中锂和铜的含量较高,铊的含量很低,铬、镍、镉、铅、砷、硒和钼7种元素的平均含量为0.55～4.42μg/g;②雪茄烟中铬、镍、砷、钼、镉、铊和铅的含量一般高于烤烟型卷烟,而硒元素的含量则相反,但差别较小;烤烟型卷烟中锂和铜的含量与雪茄烟没有显著差异;③高档卷烟中的锂、镍、镉、铊和铬含量较低,而砷、铅的含量较高;不同价位卷烟的铜、硒和钼含量差异不显著。     

In Vitro Digestion of Raw,Roasted, and Pressure-Flaked Corn, ,

We compared raw, roasted, and pressure-flaked com in dry matter and starch digestion studies in vitro. For dry matter digestion, incubations were 1, 4, 8, 16, 24 and 48 h. Dry matter digestion was increased in hours 1 through 24 by processing. Digestion in the 48-h period was decreased by processing which suggests that processing may increase the ease of utilization but not total utilization. Roasting decreased 48-h dry matter digestion more than pressure flaking. Starch digestion with incubations 1, 4, 24, and 48 h favored processed corn at all hours except 4. The 48-h observations from both studies indicate that while processing enhances starch utilization, it impairs utilization of other components in the grain. Prediction equations for dry matter and starch digestion for each corn treatment from length of incubation period and squared length of incubation period had multiple correlations of .96 or greater.     

The levels of zinc, copper, manganese, selenium, chromium, nickel, cobalt, and aluminium in the meat, liver and kidney of swedish pigs and cattle

The levels of zinc, copper, manganese, selenium, chromium, nickel, cobalt, and aluminium were determined in samples of meat, liver and kidney from pigs and cattle from Swedish slaughterhouses. The results have been compared with those reported from other investigations carried out in recent years. For zinc, copper, manganese and selenium, the mean levels found in the different tissues were very similar to those reported in previous studies. The mean levels of chromium and nickel were found to be in the range less than 0.010-0.015 mg/kg, regardless of the type of tissue. Cobalt levels ranged from 0.001 to 0.043 mg/kg, the highest levels being in the liver samples. The mean levels of aluminium were between 0.024 and 0.068 mg/kg. Tissues from cattle contained approximately twice as much aluminium as tissues from pigs. Analytical quality assurance was carried out by analysing standard reference materials. A great effort was made to minimize and check contamination. This may partly explain the fact that the levels of chromium, nickel, and aluminium found in the present study are among the lowest reported.     

The levels of zinc, copper, manganese, selenium, chromium, nickel, cobalt, and aluminium in the meat, liver and kidney of swedish pigs and cattle

Summary The levels of zinc, copper, manganese, selenium, chromium, nickel, cobalt, and aluminium were determined in samples of meat, liver and kidney from pigs and cattle from Swedish slaughterhouses. The results have been compared with those reported from other investigations carried out in recent years. For zinc, copper, manganese and selenium, the mean levels found in the different tissues were very similar to those reported in previous studies. The mean levels of chromium and nickel were found to be in the range <0.010–0.015 mg/kg, regardless of the type of tissue. Cobalt levels ranged from 0.001 to 0.043 mg/kg, the highest levels being in the liver samples. The mean levels of aluminium were between 0.024 and 0.068 mg/kg. Tissues from cattle contained approximately twice as much aluminium as tissues from pigs. Analytical quality assurance was carried out by analysing standard reference materials. A great effort was made to minimize and check contamination. This may partly explain the fact that the levels of chromium, nickel, and aluminium found in the present study are among the lowest reported.

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Gehalt an Zink, Kupfer, Mangan, Selen, Chrom, Nickel, Kobalt und Aluminium in Fleisch, Leber und Nieren von schwedischen Schweinen und Rindvieh

Zusammenfassung Es wurde der Gehalt an Zink, Kupfer, Mangan, Selen, Chrom, Nickel, Kobalt und Aluminium in Fleisch, Leber und Nieren vom Schwein und Rind aus schwedischen Schlachthäusern bestimmt. Diese Ergebnisse wurden mit denen anderer Untersuchungen verglichen. Die Durchschnittswerte für Zink, Kupfer, Mangan und Selen in verschiedenen Geweben waren ungefähr die gleichen wie in früheren Untersuchungen; die für Chrom und Nickel lagen alle im Intervall <0,010 bis zu 0,015 mg/kg, unabhängig von der Art der Gewebe, und die für Kobalt zwischen 0,001 und 0,043 mg/kg, mit den höchsten Werten in der Leber. Für Aluminium ergaben sich Durchschnittswerte zwischen 0,024 und 0,068 mg/kg, wobei die Gewebe vom Rind ungefahr doppelt so viel Aluminium enthalten wie die Gewebe vom Schwein. Die analytische Qualitätskontrolle wurde mit Referenzmaterial durchgeführt. Viel Arbeit wurde zur Minimierung und Kontrolle der Kontamination aufgewendet. Das kann zu einem Teil erklären, daß die Werte von Chrom, Nickel und Aluminium unserer Untersuchung zu den niedrigsten bisher veröffentlichten Werten gehören.

     

The effect of storage of canned juices on content of the metals Fe, Cu, Zn, Pb, Sn, Al, Cd, Sb and Ni

The increase in concentration of iron, copper, zinc, lead, antimony, aluminium, cadmium, tin and nickel over a 2 year's time of juices of peach (prunus persica), pear (pyrus communis), apricot (prunus vulgaris) and apple (malus pumila) was determined. The results show a considerable increase in Fe, Cu, Pb, Zn and Sn with time, while the change in Al, Cd, Ni and Sb is negligible.