复合香辛料提取物对冷藏猪肉糜氧化及品质特性的影响

为探究桂皮、生姜、八角茴香复合香辛料提取物对冷藏期间猪肉糜氧化稳定性及品质的影响,分别向猪肉糜中加入浓度为0.3%、0.7%、1.1%的香辛料提取物溶液,测定不同处理组的硫代巴比妥酸值（Thiobarbituric acid reactive substances,TBARS）、蛋白质羰基、总巯基、pH、蒸煮损失、色差、质构特性等指标,并通过电镜观察其微观结构。结果表明：添加复合香辛料提取物的猪肉糜TBARS值、羰基含量和巯基损失量显著低于空白组（P＜0.05）,添加浓度为0.7%和1.1%两组间无显著差异;与空白组相比,冷藏后期3个不同提取物浓度组肉糜的pH、蒸煮损失、L*值、a*值、质构特性均有显著改善（P＜0.05）,并降低了因氧化诱导引起的微观结构的改变,但1.1%浓度组肉糜a*值较其他浓度组低（P＜0.05）,说明高浓度的复合香辛料提取物对肉糜色泽有一定的负面影响。综上所述,添加浓度为0.7%的复合香辛料提取物可有效抑制冷藏猪肉糜的氧化和品质的劣变。     

姜黄素微胶囊对冷藏猪肉糜氧化稳定性及品质的影响

为提高冷藏猪肉糜的氧化稳定性和品质,以姜黄素为芯材,大豆分离蛋白和β-环糊精为壁材,利用冷冻干燥法将姜黄素微胶囊化。通过测定不同处理组（0.20 g/kg 姜黄素微胶囊、0.35 g/kg姜黄素微胶囊、0.50 g/kg姜黄素微胶囊、0.1 g/kg 丁基羟基茴香醚（BHA）和对照组）冷藏猪肉糜的硫代巴比妥酸反应物（TBARS）值、总巯基含量、总羰基含量、pH、蒸煮损失率及色差,研究姜黄素微胶囊对猪肉糜脂质和蛋白质的抗氧化效果及其对猪肉糜品质的影响。结果表明,添加0.50 g/kg姜黄素微胶囊的猪肉糜的TBARS值和总羰基含量显著低于对照组（P＜0.05）,总巯基含量显著高于对照组（P＜0.05）,与添加0.1 g/kg BHA效果接近,姜黄素微胶囊可以减少猪肉糜冷藏期间pH值和颜色的变化,显著降低猪肉糜冷藏过程中的蒸煮损失率。综上所述,0.50 g/kg姜黄素微胶囊能够显著抑制冷藏猪肉糜的脂肪和蛋白氧化,更好地保持其冷藏品质。     

猪血浆蛋白水解物在生猪肉糜中抗氧化效果的研究

在生猪肉糜中添加0.5%,1.0%,1.5%,2.0%的猪血浆蛋白碱性蛋白酶5h水解物,并与添加0.02%丁基羟基茴香醚(butylated hydroxyanisole,BHA)的生猪肉糜进行比较。在冷藏过程中测定肉糜的红度值(a*值)、pH值、TBARS值、羰基含量,并对感官指标进行评定,研究其抗氧化效果。试验结果表明,与对照组相比,添加水解物的处理组在7d内能显著抑制脂肪的氧化,增加肉糜鲜红的色泽,且添加量越大效果越好,但不如添加BHA处理组的好。同时感官评定得出猪血浆蛋白水解物在颜色、降低脂肪氧化异味等方面都具有较好的效果。     

电压梯度与脂肪含量对欧姆加热肉糜制品加热速率和品质的影响

利用欧姆加热(3,6,9V/cm)和80℃水浴方式,加热不同脂肪含量(10%,20%,30%)的肉糜制品至中心温度72℃,并保持5min,对比分析产品的色泽、脂肪氧化及微生物菌落数的变化。结果表明,欧姆加热所需时间显著少于水浴加热(p<0.05),且电压增大和脂肪含量减少,可缩短加热时间;欧姆加热与水浴加热的肉糜制品的红度值a*无显著差异;以3V/cm欧姆加热的肉糜制品TBARS值高于水浴加热和6,9V/cm欧姆加热的制品。     

柠檬酸铁作为发色剂对改善羊排色泽的研究

通过L8(23)正交试验,研究了不同浓度条件下的柠檬酸铁、柠檬酸和L-抗坏血酸钠对羊排的发色作用。影响羊排发色效果的因素依次为柠檬酸铁与柠檬酸的共同作用、柠檬酸铁单独作用、柠檬酸铁与抗坏血酸钠的共同作用、柠檬酸的单独作用和抗坏血酸钠的单独作用。当柠檬酸铁、柠檬酸和L-抗坏血酸钠的的质量比为2∶1∶2时的发色效果最佳,且当柠檬酸铁的质量分数为0.05%,柠檬酸的质量分数为0.025%,L-抗坏血酸钠的质量分数为0.05%时的发色效果好于试验中的其余组。     

三种多酚类物质协同L-精氨酸对冷藏鸡肉糜氧化稳定性和品质的影响

为探讨苹果多酚（Apple polyphenols,Ap）、葡萄籽提取物（Grape seed extraction,GSE）和茶多酚（Tea polyphenols,Tp）分别协同L-精氨酸（L-arginine,L-Arg）对冷藏鸡肉糜氧化稳定性和品质特性的影响,在肉糜中添加5 g/kg L-Arg,再分别加入0.2 g/kg的Ap、GSE、Tp,以添加0.2 g/kg丁基羟基茴香醚（Butylated hydroxy anisole,BHA）作为阳性对照,分别在冷藏1、3、5、7 d时测定各组鸡肉糜硫代巴比妥酸（Thiobarbituric acid reactive substances,TBARS）值、总巯基含量、羰基含量、表面疏水性、pH、蒸煮损失率和色度值。结果表明,与空白（不添加多酚类物质、L-精氨酸及BHA）和BHA相比,L-Arg+Tp可以更好地抑制鸡肉糜的TBARS、羰基含量、pH和表面疏水性的升高,减缓总巯基含量和红度值的降低。L-Arg+Ap和L-Arg+GSE与BHA的抗氧化作用相近。综上所述,在冷藏过程中L-Arg协同3种多酚类物质均可以抑制鸡肉糜的脂肪和...     

壳聚糖与生姜提取物复合膜在冷却猪肉保鲜中的应用

以冷却猪肉为试材,通过测定4℃冷藏15 d期间菌落总数、p H、TBARS值、TVB-N值以及感官评价等指标的变化,探讨壳聚糖与不同浓度(60%、80%和100%)生姜提取物复合膜对冷却猪肉的保鲜效果和抗氧化作用。结果表明,添加生姜提取物具有一定的浓度效应,其中80%和100%生姜提取物+壳聚糖复合涂膜处理能有效抑制冷却猪肉菌落总数和p H的上升,抑制脂质过氧化,保持较高水平的感官品质,且保鲜效果优于单独壳聚糖涂膜处理,能延长冷却肉的货架期至15 d以上。     

山苦茶抗氧化功能研究

在猪油中添加质量分数0.2%的山苦茶浸出物,在烘箱中以60℃贮存,POV值表明,处理后的山苦茶比对照可延长5 d;在猪油中添加质量分数0.02%抗坏血酸、0.02%柠檬酸和0.1%的山苦茶浸出物,有抗氧化协同增效作用;山苦茶浸出物对超.OH,DPPH.和O2-.的清除率较好。     

欧姆加热对肉制品中大肠杆菌杀灭效果及其品质影响

研究了频率、加热温度和保温时间对欧姆加热肉制品大肠杆菌数、色泽及脂肪氧化的影响。结果表明,欧姆加热肉糜制品中大肠杆菌残存率显著高于水浴加热,脂肪氧化情况较水浴加热条件下高,a*值较水浴加热低;延长保温时间可提高欧姆加热的杀菌效果,对色泽、脂肪氧化影响不显著;在工频(50 Hz)下欧姆加热的杀菌效果最好,且杀菌效果随着频率的上升有下降趋势,在高频段(100,200,400 Hz)加热时,TBARS值比低频段时低、a*值较低频处理下的高。     

碧萝芷提取物对肉糜的抗氧化研究

以肉糜为试材,研究2~4 ℃储藏条件下碧萝芷、生姜、大蒜、阿魏酸、枳实提取物对其抗氧化作用。结果表明,在8 d的储藏期内,空白对照组的丙二醛（MDA）含量、过氧化值、酸价和挥发性盐基氮均呈明显上升趋势,添加碧萝芷提取物能显著抑制脂肪的酸败变质,在0~2 d,碧萝芷组的MDA值基本没有变化,4~8 d内MDA值反而有下降的趋势,表明碧萝芷不仅可以抑制氧化产物的产生,而且可能对已经产生的氧化产物MDA有降解作用。碧萝芷对过氧化值和酸价的抑制作用分别是空白对照组的1.5倍和2倍,但总体上对挥发性盐基氮的抑制效果不明显。表明碧萝芷提取物对2~4 ℃储藏的肉糜具很强的抗氧化作用。     

不同保鲜剂处理对切割生菜品质影响的研究

研究了5种保鲜剂（1mmol／L苯甲酸、0．5％氯化钙、1．0％过氧化氢、1．0％维生素C、1．0％柠檬酸）处理对新鲜切割生菜（10～15mm切割度）在3℃贮藏期间品质变化及贮藏效果的影响。结果表明,在3℃贮藏条件下,5种处理中,1mmol／L苯甲酸和0．5％氯化钙显著延缓切割生菜的叶绿素、总酸、VC以及可溶性固形物含量的下降,保持了较好感官品质,贮藏到第12天仍有商品价值;1,0％过氧化氢和1,0％VC处理对保持切割生菜的品质有一定的作用,但处理效果略次于苯甲酸和氯化钙,商品贮藏期仅为8天：1．0％柠檬酸的处理效果不明显,商品贮藏期仅为6天左右。     

低浓度海盐苦卤处理对番茄种子萌发及幼苗生长的影响

以番茄种子及其幼苗为试验材料,以蒸馏水和0.40%氯化钠溶液为对照,研究番茄种子在海盐苦卤浓度为0.05%、0.10%、0.20%和0.40%处理下发芽率和发芽势。试验以Hoagland’s营养液及含0.40%和0.60%氯化钠的Hoagland’s营养液为对照,研究番茄幼苗在海盐苦卤浓度为0.05%、0.10%、0.20%和0.40%的Hoagland’s营养液处理下的株高、干重、鲜重、电导率、丙二醛含量及脯氨酸含量。结果表明：浓度为0.05%和0.10%海盐苦卤处理对番茄种子及幼苗无负面影响,且在一定程度上提高了番茄种子的发芽势,增加了番茄幼苗的株高、干重和鲜重,有效降低了番茄叶片的电导率,并且对番茄叶片丙二醛（MDA）含量及脯氨酸（PRO）含量影响很小;浓度为0.20%和0.40%海盐苦卤处理对番茄种子萌发无明显影响,对番茄幼苗的生长具有负面影响,且其负面影响低于同浓度氯化钠对番茄幼苗造成的影响。     

Efficacy of ethanolic extract of propolis in maintaining postharvest quality of dragon fruit during storage

Significant (P ≤ 0.05) differences were observed in dragon fruit quality when treated with different concentrations of ethanolic extract of propolis (EEP) (0.25, 0.50, 0.75 and 1.0%) and stored at 20 ± 2 °C and 80 ± 5% relative humidity (RH) for 20 days. Fruit treated with 0.50% EEP showed the most promising results, while fruit treated with 0.75 and 1.0% EEP showed some phytotoxic effects even after 8 days of storage. The results of gas exchange analysis also proved the efficacy of 0.50% EEP concentration. Thus, it can be concluded from the present investigation that EEP at 0.50% concentration could be used to extend the storage life of dragon fruit without any negative effects on the quality.     

白蘑菇保鲜工艺的研究

以白蘑菇为原料,采用正交试验设计优选护色剂,通过试验优选保鲜剂和贮藏温度。结果表明,0.50%柠檬酸+0.15%苯甲酸+0.15%异抗坏血酸钠抑制褐变的效果较好,抑制率可达81%;保鲜剂以0.15%焦亚硫酸钠+0.20%氯化钠+0.10%氯化钙的效果较好;贮藏温度为0℃的保鲜效果好。     

贮前抗坏血酸处理对李果实冷害及生理生化的影响

以串红李子为试材,研究了不同浓度的抗坏血酸处理对低温下贮藏的李果实冷害及生理生化的影响。结果表明,与对照相比,贮前抗坏血酸处理能推迟李果实的后熟进程,使着色过程缓慢,呼吸强度与乙烯释放量受到一定的抑制,明显降低冷害指数,抑制李果实贮藏期间冷害的发生,尤其以低浓度（0.2%）的抗坏血酸处理抑制冷害的效果最好,可保持李果实较好的贮藏品质。     

1-MCP复合杀菌剂处理对“金红宝”甜瓜常温贮藏品质的影响

为探究不同处理对甜瓜常温贮藏效果的影响,以“金红宝”厚皮甜瓜为试材,研究1-甲基环丙烯(1-MCP)、1-MCP复合杀菌剂抑霉唑处理对甜瓜采后常温贮藏保鲜效果的影响。结果表明,1-MCP和1-MCP复合杀菌剂处理的保鲜效果均显著优于对照处理。其中,在延缓抗坏血酸含量和可滴定酸含量的下降,降低腐烂率、失重率等方面,1-MCP复合杀菌剂处理的保鲜效果优于1-MCP处理。综上所述,相较其他处理,1-MCP复合杀菌剂处理的保鲜效果最好,可以有效保持甜瓜的品质。     

Shelf life of minimally processed potatoes: Part 1. Effects of high oxygen partial pressures in combination with ascorbic and citric acids on enzymatic browning

The shelf life of minimally processed potatoes is limited by enzyme-catalysed browning reactions. Generally, this phenomenon is controlled by the use of chemical reagents such as ascorbic acid, citric acid, or 4-hexyl resorcinol, but it seems that “oxygen shock” treatments are also particularly effective in inhibiting enzymatic browning. The aim of this work was to study the effects of high oxygen partial pressures in combination with ascorbic and citric acid on the development of the enzymatic browning of peeled and cut potatoes (‘Primura’ variety) that were packaged in flexible pouches and stored at 5 °C for 10 days. Different treatments, chosen in according to a central composite design, were applied to the sliced potatoes. The browning development during storage was measured by a tristimulus colorimeter. Second-order polynomial models were computed for three periods of storage (3, 7 and 10 days) to relate the independent variables (oxygen partial pressure, ascorbic and citric acid concentrations) to the colour function attributes.The effectiveness of the statistical approach offered the possibility to investigate the effects of several processing conditions involved in the enzymatic browning of minimally processed potatoes, while the response surface methodology allowed the identification of the optimum range of the independent variables which prevented browning.     

Effects of Thiourea, Thiamine and Ascorbic Acid on Growth and Yield of Maize (Zea mays L.)

Three chemicals, viz., thiourea, thiamine and ascorbic acid capable of potentiating-SH turnover, were tested with the objective to improve growth and productivity of maize. Thiourea was tested as seed-soaking and foliar-applied treatments as also in combination. Thiamine and ascorbic acid were tested as foliar sprays alone. Foliar treatments were applied at vegetative stage (30 and 45 days after sowing).
The results of the field experiment showed that seed soaking with thiourea (500 ppm) tended to improve grain yield (13.4 per cent over control), but improvement in biological yield was significant. However, seed soaking plus foliar treatment of thiourea significantly increased both biological and grain yields, besides causing significant improvement in leaf area index and number of green leaves plant^-1. The increase in grain yield ha^-1 was of the order of 34.6 per cent over control.
It was further noted that foliar sprays of thiourea (1000 ppm), thiamine (100 ppm) and ascorbic acid (100 ppm) significantly increased leaf area index, number of green leaves plant^-1 and biological yield ha^-1. These treatments also significantly increased grain yield ha^-1 by 40.6, 20.2 and 26.3 per cent, respectively over control. Improvement in maize yield with thiourea, thiamine and ascorbic acid treatments appeared to have resulted from increased photosynthetic efficiency and canopy photosynthesis on account of the biological activity of -SH group. It was also apparent that leaf senescence was delayed under the influence of these chemicals. It is therefore suggested that thiourea, thiamine and ascorbic acid are the potential bioregulators for improving photosynthetic efficiency and grain yield of maize and possibly other cereals, and that thiourea, a sulphydryl compound, holds considerable promise in this context.     

Effect of antioxidants in controlling enzymatic browning of minimally processed persimmon ‘Rojo Brillante’

‘Rojo Brillante’ is an important variety of persimmon that after removal of the astringency with high levels of CO₂, maintains firmness and sweetness, making possible its commercialization as a fresh-cut commodity. However, the commercial success of the product is limited mainly by enzymatic browning. This work presents the effect of a wide range of antioxidants on enzymatic browning of ‘Rojo Brillante’ persimmon combining in vitro (extracts and precipitates) and in vivo (cut tissue) studies. Preliminary screening of the antioxidants, determined by absorbance and color measurements of persimmon extracts and pellets, showed that 4-hexylresorcinol (Hexyl), citric acid (CA) and calcium chloride (CaCl₂) were effective at controlling browning at 10 mM; whereas, ascorbic acid (AA) required a higher concentration (25 mM). Peracetic acid, cyclodextrin, cysteine, and hexametaphosphate were not effective at controlling browning, even at a concentration of 50 mM. In in vivo studies, AA (1.12%) and CA (0.21%) were the most effective treatments to control enzymatic browning of fresh-cut material, reaching the limit of marketability in 5–7 days, whereas, Hexyl and CaCl₂ did not reach 1 day of storage. The results showed that optimum concentrations in cut tissue did not always correlate with the in vitro studies, indicating that antioxidants have an effect not only in browning reactions, but also in metabolic activity and cell wall changes during wound-induced reactions. The results provide relevant information for further development of minimally processed ‘Rojo Brillante’ persimmon during storage at 5 °C.