建立一种QuEChERS-高效液相色谱-串联质谱法,快速测定鸡肉中氟虫腈及其3种代谢产物(氟甲腈、氟虫腈砜及氟虫腈亚砜)的方法.鸡肉样品经乙腈分散,DisQuE提取管提取和DisQuE净化管净化后,采用液相色谱-串联质谱定量测定,选择性多反应监测模式检测.在0.5～20ng/mL线性范围内,氟虫腈及其代谢产物的回归方程均呈良好的线性关系,R2>0.999,在添加水平为1.0、5.0、10.0μg/kg时,平均回收率为75.2％ ～89.9％,相对标准偏差(RSD)为0.8％ ～9.2％,方法检出限为0.5μg/kg,定量限为1.0μg/kg.该方法简便快捷,灵敏度和准确度均较高,精密度较好,适用于鸡肉中氟虫腈及其代谢产物残留量的检测.

试验对不同消解方式和不同灵敏线下肉制品中钠的含量进行检测研究,结果表明:样品在不同灵敏线和不同消解方法下的测定结果没有显著性差异,但微波消解处理样品,利用第三灵敏线检测时,样品处理步骤简单,检测结果误差小,在0～160μg/mL浓度范围内,线性关系良好(R2=0.992),平均加标回收率为99.2％,因此该方法可用于肉制品中钠含量的检测.

Uniform experimental design was applied to examine the effects of high pressure and holding time on the texture characteristic of pork homogenate gelation. The results showed that the effects of high pressure and holding time on the indexes considered were nonlinear,and there were interactions between them on all indexes except gel elasticity. Gel strength and chewiness of gelation were decreased while the holding time increased at lower pressure,the trend was reverse at higher pressure; and they were decreased while the pressure increased at shorter holding time,and the trend reverse at longer holding time. Keep the pressure fixed,the trend of gel hardness were increased firstly and then decreased along with the holding time extending; At the longer holding time,gel hardness was increased along with the increasing of the pressure; but at the shorter holding time,the trend was inversed. Gel elasticity was decreased firstly and then increased along with the holding time extending when the pressure fixed,and decreased along with the increasing of the pressure when the holding time fixed. Gel gumminess increased with time under certain pressure,and also increased with the increase of pressure at a constant holding time.

Uniform design was applied to examine the effects of high pressure (75 MPa-450 MPa, 10 min-60 min) on pH value, color, NaCl content and texture of beef during marinating. The results showed that the process of curing was accelerated by high pressure and NaCl content was increased. The pH value and lightness increased with the increasing pressure (75 MPa-450 MPa), redness tend to be stable under a certain range (150 MPa-300 MPa,20 min-50 min) while hardness increased under a high level of pressure (300 MPa-450 MPa). After regression analysis, 223.5 MPa, 26.3 min was selected as the optimum conditions for marinating beef.

Uniform design was applied to examine the effects of high pressure(100～600 MPa,5～30min) and low temperature(20～ 60℃) on structure and physical-chemical property of beef.The results showed that springiness was increased by pressure(100～ 600MPa) and certain temperature(20～54.3℃).The pH value increased with the increasing pressure(75～450 MPa) under 41.6 ℃ while the effects of pressure and temperature are not additive.Lightness was increased as pressure,holding time and temperature increased,which was similar to cooked rate.At the same time,pressure could lead to accretion of hardness while holding time and temperature had the opposite effect on hardness.

The effects of varying pressure(0~500 MPa) and different pressure-holding time(0~25 min) on springiness,color,rate of water-loss of the minced chicken containing transglutaminase(0.35%) were investigated.The result showed that: a great difference on the minced chicken under conditions of varying pressure or dwell time,but within a certain pressure level(200~400 MPa) and dwell time(10~20 min) combined with transglutaminase can effectively improve the quality of the minced chicken;At 500 MPa,20 min,the minced chicken containing transglutaminase obtained the highest flexibility;A single pressure level or dwell time can not cause the significant changes of the color and the rate of water-loss of the minced chicken,but the impact of pressure on meat's characteristics is much greater than the pressure-holding time's;The quality of the minced chicken is also affected by the temperature and the enzyme reaction time.

In this paper,the types,characteristics,technological process,development and types of starter cultures,current situation,new development,new ideas and outlook in China of fermented meat were reviewed.

Uniform experimental design was applied to study the effects of using high pressure and the treatment time on water holding capacity of pork homogenate gelation.The results showed that soluble protein concentration of homogenate and water holding capacity rate of gelation were increased while the pressure and the treatment time decreased.The trend of the dehydration rate of pork homogenate gelation was varied by different conditions.With longer high pressure treatment,the dehydration rate was increased along with the increasing of the pressure;but at the shorter treatment time,the result was inversed.If the pressure is fixed,the dehydration rate was increased first and then decreased along with treatment time.

Quadratic general rotary design was adopted to study effects of pH,sodium chloride concentration and heating temperature on heat-induced gelation properties of pork homogenate from hind leg.The results showed that protein concentration of homogenate increased with the increasing of pH and sodium chloride concentration within a certain range.There were interactions between pH and sodium chloride concentration on purge loss,water holding capacity and gelation strength.Purge loss declined with the increasing of pH and sodium chloride concentration while it increased with the increase of heating temperature.To some extent,the correlation of water holding capacity of gelation with pH,sodium chloride concentration and heating temperature were positively correlated.At different heating temperatures,the effect of pH and sodium chloride concentration on gelation strength were similar.The optimization calculation showed that the optimum condition of the formation of gelation was pH6.33,sodium chloride concentration 0.67mol/L,heating temperature of 75℃.

A series of single factor experiments were conducted to evaluate effects of high-pressure intensity(200-600 MPa) and pressure-holding time(10-30 min) on preservative properties of roast chicken during storage at 4 ℃.Results indicated that sterilization effect exhibited an obvious improvement with the increase of high-pressure intensity.A better sterilization effect at a high-pressure intensity of 500 or 600 MPa was observed,which reduced total bacterial and lactic acid bacterial counts by three or four magnitude order.Moreover,the bacterial count in these treated samples remained the lowest level over the whole storage period of 7 days.Sterilization effect was also improved with the extension of pressure-holding time up to 15 min and tended to be stable in spite of longer pressure-holding time during the whole storage period.The lowest growth rates of total bacteria and lactic acid bacteria were both achieved in treated samples with 20 min of pressure-holding time or longer,which showed the best preservative properties.Considering comprehensively,the optimal treatment conditions for roast chicken were high-pressure intensity of 500 MPa and pressure-holding time of 20 min.

Ultra-high pressure treatment attracted researchers for a new non-heating technique.Effects of ultra-high pressure treatment on color,tenderness,and flavor were reviewed in this paper,and these can be the references to the research and application of ultra-high pressure treatment on meat and meat products.

Quadratic general rotary design was adopted to study effects of pH value,sodium chloride concentration and heating temperature on heat-induced gelation texture properties of pork homogenate from hind leg.The results showed that different treatments had influence on the characteristics of gels.Under different heating temperature,the effects of pH value and sodium chloride concentration on hardness,springiness,cohesiveness,gumminess and chewiness of gelation were consistent and interactive.When the pH value was lower,the hardness,springiness,cohesiveness,gumminess and chewiness of gelation were increased as sodium chloride concentration increased;when the pH was higher,the effect of sodium chloride concentration on the hardness,springiness and gumminess of gelation was less,but cohesiveness was increased with the increasing sodium chloride concentration.Simultaneously,with the heating temperature increased,the hardness and gumminess of gelation were increased,cohesiveness and chewiness were decreased and springiness was little changed.

Change of total bacteria number was investigated,spoilage bacteria of vacuum-packaged roasted chicken was isolated and identified,and changes of microflora composition were analyzed at room temperature and chilled temperature storage conditions. The results showed that isolated 13 special colonies from total bacterial count plates included one strain of Bacillus,Lactic acid bacteria,Micrococcus and Brochothrix thermosphacta,two strains of Pseudomonas and Aeromonas,and five strains of Enterobacteriaceae. No significant effect of temperature(4℃ and 25℃)on changes of microflora composition was found:Lactic acid bacteria was the main spoilage bacteria during the whole storage,next was Pseudomonas,Enterobacteriaceae increased almost twice than the initial at room temperature,while did not change at chilled temperature,but Staphylococcus and Brochothrix thermosphacta decreased.