Changes in the physicochemical,structural and emulsifying properties of chicken myofibrillar protein via microfluidization

Microfluidization is a novel and effective technology to improve the properties of myofibrillar protein. The effects of microfluidization with varying pressures (0–120 MPa) on the physicochemical, structural and emulsifying properties of chicken myofibrillar protein (CMP) were studied. Microfluidization treatment remarkably increased the absolute ζ-potential, contact angle, solubility, emulsifying ability and emulsifying stability of CMP. Simultaneously, the turbidity of CMP decreased. After microfluidization treatment, more α-helix structures were transformed into disordered structures, more hydrophobic and negatively charged groups were exposed, leading to improvements in CMP properties. After 90 MPa treatment, the absolute ζ-potential, storage modulus, loss modulus and dynamic apparent viscosity of CMP-camellia oil emulsion reached the maximum values. The hydrophobic interaction between CMP and camellia oil induced CMP to expose more hydrophobic and negatively charged groups, leading to the improved emulsifying properties of CMP. Our results demonstrate that microfluidization treatment has great potential to improve the product qualities of emulsion-type meat products.     

沙棘葡萄复合饮料发酵工艺初探

以沙棘与葡萄为原料,采用单因素和响应面试验分析沙棘与葡萄复合比例、初始糖度、发酵温度、酵母添加量对沙棘葡萄复合饮料品质的影响。结果表明,沙棘葡萄复合饮料最佳发酵工艺条件确定为沙棘汁与葡萄汁复合比例7∶3（V/V）,初始糖度12.6 °Bx,发酵温度25 ℃,酵母添加量为0.03%。在此条件下,发酵所得复合饮料口感柔和、香气浓郁,爽口,感官评分为93分。     

喷雾干燥法制备打瓜籽蛋白粉的研究

为得到优质的打瓜籽蛋白粉,采用喷雾干燥法,以蛋白粉的集粉率和分散系数(PDI)为指标,探讨了进料温度、进风温度、进料流量和雾化压力对喷雾干燥效果的影响。通过均匀实验,得到打瓜籽蛋白粉制备的最佳工艺参数:进料温度20℃,进风温度180℃,进料流量300 m L/h,雾化压力140 k Pa,此时打瓜籽蛋白粉的集粉率为50.43%,PDI为80.1%,所得蛋白粉为粉末状,奶白色,无异味,无结块,功能性质良好。      

GC-MS分析使用不同提取工艺获得的沙枣花挥发性成分

这项研究采用水蒸气蒸馏法、有机溶剂浸提法、真空泵抽取吸附采集法、固相微萃取法以及超临界CO2萃取法对新疆沙枣花挥发油进行提取,并探讨不同提取方法对沙枣花挥发性化合物成分的影响。通过气相色谱-质谱(GC-MS)联用技术对沙枣花挥发油的化学成分进行分析鉴定,用峰面积归一法确定各组分的相对含量。共分离鉴定出139种化合物,其中共检测出烃类22种(占21.3%)、醛类10种(占1.38%)、酯类47种(占62.18%)、酮类7种(占0.6%)、醇类21种(占9.52%)、酸类14种(占1.86%)、苯环类7种(占1.66%)、酚类5种(占1.14%)、其它物质6种(占0.33%)。其中共有成分4种,分别是2,3-丁二醇、苯乙酸乙酯、苯乙醇、反式-肉桂酸乙酯。     

酿酒葡萄皮渣中多酚物质的提取及其对羟基自由基的清除研究

本文以酿酒葡萄皮渣为研究对象,通过单因素试验以及正交试验研究了超声波辅助提取对葡萄皮渣多酚得率的影响,并对工艺条件进行优化,确定了提取葡萄皮渣多酚的最佳工艺参数为:超声时间30 min,温度60℃,料液比1:20(g/mL),超声功率200 W,在该条件下葡萄皮渣多酚得率为6.72 mg/g。并研究了葡萄皮渣多酚粗提物对羟基自由基的清除能力,结果表明:在实验浓度范围内,当添加的葡萄皮渣多酚的质量浓度为0.79 mg/mL时,对羟自由基的清除率可达78.64%。     

Understanding the influence of PEF treatment on minerals and lipid oxidation of wet- and dry-aged venison M. longissimus dorsi muscle

Pulse electric fields (PEF) treatment can be used to improve meat quality attributes, such as tenderness and mass transfer kinetics of dry ageing of meat. This study investigated the effect of PEF (high-PEF 10 kV, 50 Hz, 20 μs; low-PEF 2.5 kV, 50 Hz, 20 μs) and ageing method (wet- and dry-ageing) on venison mineral profiles, and lipid and conjugated linoleic acid (CLA) oxidative stability. Twelve loins from six red deer were assigned to six groups: no-PEF dry-aged control, no-PEF control, wet-aged Low-PEF, dry-aged Low-PEF, dry-aged High-PEF, wet-aged High-PEF. Secondary oxidation products contents were not affected by PEF treatment (p > 0.05), but were affected by dry ageing (p < 0.05). CLA was stable across PEF treatments and different ageing regimes (p > 0.05). PEF treatments did not have any effect on minerals (p > 0.05). This study validates the safety of using PEF in venison processing with limited detrimental oxidative modifications.Industrial relevance - PEF treatment and the dry-ageing regimes applied to venison in the present study did not produce excessive oxidative by-products that could compromise product quality. The application of both PEF treatments (HPEF 10 kV, 50 Hz, 5 μs; LPEF 2.5 kV, 50 Hz, 5 μs) could potentially improve the drying of venison with a low risk of increasing oxidation.     

Study of taste-active compounds in the water-soluble extract of mature Cheddar cheese

The chemical composition of the water-soluble extracts of mature Cheddar cheese were identified, with the emphasis on understanding the interplay of compounds contributing to the savoury taste in Cheddar. The ultra-filtered water-soluble extracts of two mature Cheddar cheeses were fractionated by gel permeation chromatography (GPC). By sensory evaluation, two taste-active GPC fractions were identified from each cheese. On the basis of chemical profiling of these fractions, aqueous model tastant mixtures were prepared and sensory omission tests carried out. Glutamic acid, organic acids and mineral salts were the main tastants, whereas the other amino acids had a limited impact on taste. The characteristic umami taste was explained by a synergistic effect of glutamic acid and salts. Matching umami taste intensities were obtained from different concentrations of glutamic acid and salts. Unmasking of a bitter or sweet taste from mixtures of sub-threshold concentrations of amino acids without glutamic acids was also observed.     

壳聚糖可食用膜对辣椒贮藏生理的影响

研究了10℃时不同浓度壳聚糖可食用膜对辣椒贮藏生理指标的影响,结果表明:壳聚糖可食用膜处理能够明显降低呼吸强度,抑制叶绿素降解,减少贮藏期间辣椒组织中丙二醛的产生,减缓Vc含量以及超氧化物歧化酶活性的降低,延缓辣椒果实的衰老进程.     

高压CO_2对树莓汁品质的影响

研究了高压二氧化碳(High Pressure Carbon Dioxide,HPCD)对树莓汁品质的影响。处理条件为:压强10、20、30MPa,温度35、45、55℃,时间15、30、45、60min。测定其浊度、褐变指数、悬浮稳定性、pH、可溶性固形物含量和色泽。处理后样品褐变指数降低,浊度和悬浮稳定性增加,pH、可溶性固形物含量和色泽没有显著变化。     

响应面分析法优化乙醇提取向日葵壳红色素工艺研究

以向日葵壳为原料提取红色素。在单因素试验的基础上进行中心组合设计,利用响应面法对其提取工艺参数进行优化。结果表明：提取温度54℃、提取时间112min、液料比22:1(mL/g)时,向日葵壳色素提取量最高为663.03mg/100g,预测值为661.74mg/100g,与实测值相符。以向日葵壳提取色素可以提高向日葵的附加值。