Improvement of tenderness and water holding capacity of spiced beef by the application of ultrasound during cooking

The aim of this study was to assess the effects of power ultrasound‐assisted (0, 400, 600, 800 and 1000 W, frequency of 20 kHz) cooking (80, 100, 120 min) on spiced beef. The results showed that power ultrasound could significantly increase the salt content (P < 0.05). For water holding capacity, the ultrasonic treatment could significantly reduce the pressure loss and free water content while improving the immobilised water content (P < 0.05). And ultrasonic treatment improved hardness compared with control (P < 0.05). However, the effects on the springiness, the chewiness and the resilience of the spiced beef were not significant (P > 0.05). As for microstructure, the myofibrils of beef were ruptured by ultrasonic treatment along with the Z‐lines leading to the muscle swelling. The results indicated that the application of ultrasound during cooking could effectively promote the penetration of salt, improve the water holding capacity and ameliorate the tenderness of spiced beef.     

脂肪含量对低盐猪肉凝胶品质的影响

以未添加磷酸盐的低盐猪肉凝胶作为研究对象,考察脂肪添加量(0～20%)对猪肉凝胶保水、质构和色泽的影响。结果显示,脂肪添加量在15%～20%范围内,凝胶保水性显著增加(P<0.05);添加5%以上的脂肪,可显著提高猪肉凝胶的L*值(P<0.05);在脂肪添加量不高于5%条件下,猪肉凝胶可形成良好的硬度、弹性、凝聚性和咀嚼性,并能保持较好的红度值(a*值),利于开发低脂猪肉制品。     

热风干燥制备马铃薯颗粒全粉试验研究

采用两因素三水平的全面正交试验,研究热风干燥温度和切片厚度对马铃薯干燥特性及对马铃薯颗粒全粉堆积密度、水合能力的影响.结果表明:马铃薯片的干燥过程分为调整、等速和降速3个干燥阶段.其中等速和降速干燥阶段的速率明显受到干燥温度和切片厚度的影响.粒径为0.125mm～0.175mm之间的马铃薯颗粒全粉堆积密度为0.73 g/mL～0.80g/mL、水合能力(WHC)为每克样品中含水2.98～6.01,复水后的马铃薯泥具有沙口性和浓郁的马铃薯香味.     

草鱼盐溶蛋白保水性及流变性质的研究

研究了混合磷酸盐对盐溶蛋白的凝胶保水性影响及对其流变性进行测定,分析蛋白动态流变性质以及凝胶强度与保水性的相关性。结果表明:添加磷酸盐可提高盐溶蛋白的保水性;添加不同配比的混合磷酸盐对盐溶蛋白凝胶的保水性和凝胶强度影响显著;盐溶蛋白最终凝胶强度很大程度上受42.1～45.6℃或之前的凝胶强度的影响,盐溶蛋白的凝胶强度与凝胶的保水性不相关。     

微粒玉米淀粉糊精的性质研究

以玉米淀粉为原料，分别以70％EtOH2%HCl2h和99．9％EtOH-2％HCl5h水解处理，结合球磨，获得微粒淀粉糊精，并对此两种微粒淀粉糊精进行了研究。结果表明，两样品均具有2μm以下的粒径，X-射线衍射图谱保持A型特征峰，持水性比原淀粉有显著提高。感官及理化特性符合麦芽糊精的相关标准，有望用作脂肪代用品。     

降低食盐添加量对火腿肠的感官、质构及保水特性的影响

为研制低钠盐火腿肠,研究降低食盐添加量对火腿肠质量的影响。设置6个不同的食盐添加量梯度(以原料猪肉质量为基准计)：3%(对照)、2.5%、2.0%、1.5%、1.0%、0.5%,分别对产品的水分活度、保水性和质构进行测定,同时进行感官评分。结果表明：随着食盐添加量的降低,火腿肠的水分活度逐渐升高,而保水性逐渐下降;质构测定显示,产品的硬度、咀嚼度、黏聚性也随着食盐添加量的下降而降低,当食盐添加量极低时,这种下降趋势很明显,但弹性却变化不大;感官评定结果表明,随着食盐添加量的降低,火腿肠颜色变浅,切面粗糙,咸味下降,当食盐添加量降低到1.0%时不易被接受。因此,食盐对猪肉火腿肠的感官、质构和保水性等有着重要的作用,本研究为进一步调整配方开发低钠盐火腿肠提供了重要参考。     

影响猪肉持水性因素的初步研究

本研究讨论了热处理温度、热处理时间,混合盐水中食盐用量、复合磷酸盐用量及复合食品胶用量对猪肉经处理后持水性的影响和各因素之间的关系,得出了经处理后肉重与各因素间的二次回归方程。     

Any link between integrin degradation and water-holding capacity in pork?

In order to investigate a possible relationship between integrin degradation and water-holding capacity (WHC), integrin was quantified using western blot, and water mobility and distribution was measured by proton NMR T(2) relaxometry at 24h postmortem in pork (n=30) with a large variation in WHC (drip loss varying from 2.8% to 11.3%). Regression analyses revealed correlation coefficients of r=-0.32 (P=0.08) and r=0.40 (P=0.03) for the correlations between the content of integrin determined by western blot analysis and WHC determined as either drip loss or by NMR, respectively. Water mobility and distribution was also measured in 18 meat samples upon 7 days of aging, which revealed a correlation (r=0.54) between integrin content determined by western blot analysis 24h postmortem and the mobility of the myofibrillar water (T(21) relaxation time) at day 7. In contrast, no correlation could be established between integrin content 24h postmortem and WHC at day 7 determined by NMR as the amount of extramyofibrillar water (T(22) population) (r=-0.01). In conclusion, both visualisation by CLSM and quantification of integrin by western blot analyses of suggested that a strong link between integrin degradation and WHC in pork is questionable, whereas integrin degradation seems to have impact on the succeeding development in the mobility of the myofibrillar water.     

Dietary creatine monohydrate has no effect on pork quality of Danish crossbred pigs

Creatine content in the muscle may delay postmortem lactate formation and postpone the pH decline, hence potentially improving the water-holding capacity (WHC) as shown in a previous study including purebred Duroc pigs, although the same study did not find any effect on meat from purebred Landrace pigs. In the present study Danish D(LY) crossbreeds were supplemented with 0 or 50g creatine monohydrate (CMH)/d for five days prior to the slaughter. CMH supplementation had no effect on meat quality indicators (pH and temperature), meat quality attributes (WHC and colour) or eating quality (juiciness and tenderness) of meat from the D(LY) crossbred pigs. As a consequence the D(LY) crossbreed was classified as a non-responder to CMH supplementation.