中草药醇提物抑菌筛选及对草莓保鲜效果的研究

采用菌丝生长速率法筛选出对草莓采后主要病原菌抑制效果最佳的中草药单剂及复配组合,并以腐烂率为调查指标,通过正交试验研究确定复配的最佳保鲜质量浓度配比,即丁香和蛇床子均为1g/L、补骨脂1.5g/L。使用中草药复合保鲜剂、丁香单剂、化学保鲜剂对草莓进行防腐保鲜处理,调查不同处理对草莓常温贮藏过程中各种保鲜指标的影响。结果表明：各保鲜剂处理组均能降低草莓贮藏过程中的质量损失率和腐烂率,减少可溶性固形物及VC含量的下降,且复合中草药处理组的各种保鲜指标均优于丁香单剂和化学防腐保鲜剂多菌灵。     

中国毛虾(Acetes chinensis)虾皮复合保鲜剂筛选及保鲜效果的研究

为解决中国毛虾干制品(虾皮)在常温流通、销售过程中容易腐败变质的问题,从山梨酸钾、双乙酸钠、Nisin三种抑菌保鲜剂和异抗坏血酸钠、竹叶抗氧化物、植酸三种抗氧化剂中筛选出对虾皮保鲜效果较好的两种抑菌剂和一种抗氧化剂,结果得到山梨酸钾、双乙酸钠和异抗坏血酸钠作为虾皮的复合保鲜剂;通过正交实验优化得到最佳复合保鲜剂的配比为0.10%山梨酸钾、0.05%双乙酸钠和0.2%异抗坏血酸钠。中国毛虾经复合保鲜剂处理后,常温贮藏(25℃)过程中细菌总数和挥发性盐基氮(TVB-N)增加缓慢,货架期延长至25 d,比对照组延长了约15 d,保鲜效果较好,研究结果为虾皮保鲜及其品质控制提供了一定的科学依据。     

粉唑醇在草莓生长和加工过程中对映体选择性降解行为规律

为研究手性农药粉唑醇在草莓生长及草莓酒加工过程中的选择性降解行为,对草莓进行田间施药,并将草莓模拟家庭酿酒方式加工。样品采用超高效合相色谱-串联质谱进行手性拆分并检测。结果表明,在草莓生长中两个对映体没有明显的选择性降解行为,（－）-R-粉唑醇在草莓上的半衰期为13.80?d,（＋）-S-粉唑醇在草莓上的半衰期为13.60?d。而在草莓酒发酵过程中,统计学分析显示存在明显的选择性降解行为（P＜0.05）,（＋）-S-粉唑醇优先降解。清洗处理组（－）-R-粉唑醇在草莓酒中的半衰期为38.06?d,（＋）-S-粉唑醇的半衰期为29.90?d。未清洗处理组（－）-R-粉唑醇在草莓酒发酵中的半衰期为29.31?d,（＋）-S-粉唑醇半衰期为22.14?d。     

植酸对草莓保鲜的研究

将刚采摘的草莓浸入不同浓度的植酸和山梨酸钾溶液中30s,然后在常温条件下保存,通过对草莓进行糖分和酸度测定,研究植酸对草莓储藏稳定性的影响.结果表明:浓度为0.05%～0.15%植酸用于草莓保鲜,可以延缓果实中维生素的降解,保持果实中的还原糖和总酸含量,在常温条件下可以保鲜一周,明显延长草莓贮存期.     

涂膜保鲜萝卜效果及糠心研究

本文研究了白萝卜采用不同涂膜处理在常温下贮藏保鲜效果,探讨了萝卜贮藏过程中主要生理生化变化研究了萝卜糠心程度与含水量、呼吸强度及容重的关系。结果表明：在常温条件下,经过３个月的贮藏,海藻酸钠涂膜保鲜萝卜腐烂率最低,为４０％：魔芋精粉涂膜萝卜糠心率最低,为４４.３％。萝卜糠心程度与萝卜含水量、容重及呼吸强度呈极显著相关。     

复合保鲜剂对百香果酱贮藏品质的影响

为了探究复合保鲜剂对百香果酱品质的影响,在果酱加工过程中添加不同比例的复合保鲜剂,在常温(25℃)下贮藏,研究其贮藏品质特性。结果表明,与对照组相比,0.042%山梨酸钾、0.015%脱氢乙酸钠、0.02%茶多酚(1000g百香果,加入0.42g山梨酸钾,0.15g脱氢乙酸钠,0.2g茶多酚)处理组效果最佳,复合保鲜剂处理组货架期延长,显著抑制菌落总数的增加,保持总糖含量,抑制褐变,且能有效保持百香果酱在贮藏期间的品质。     

Op-Ca保鲜剂对鲅鱼的保鲜效果

报告了常温下 Op- Ca保鲜剂对鲅鱼 (scombero-morus niphous)的保鲜效果。用 0 .0 5%的 Op- Ca保鲜剂溶液浸泡鲅鱼 30 min后在常温 (2 3℃ )下贮藏 ,通过感官评价和细菌总数、T- VBN值等鲜度指标的测定 ,发现该保鲜剂对常温下的鲅鱼有较好的保鲜效果 ,能够延长常温下鲅鱼的保鲜期2 d以上。     

壳聚糖涂膜常温保鲜草莓的试验研究

以壳聚糖涂膜对草莓进行常温保鲜试验,结果表明:以1.25%壳聚糖涂膜的草莓其VC、总酸、总糖、可溶性固形物含量最高,腐烂指数、呼吸强度、失重率最低,贮藏效果最好。     

NISIN、EDTA和山梨酸钾在冷却肉贮藏保鲜中的交互效应分析

添加NISIN、EDTA和山梨酸钾复合保鲜剂,真空包装后(4±1)℃贮藏鲜肉,以细菌总数作为评价鲜肉贮藏效果的指标。以三因子中心组合实验探讨复合保鲜剂对鲜肉保鲜的影响,结果表明:3种保鲜剂以NISIN 0.05%、EDTA 0.112%、山梨酸钾0.054%添加,效果最好。EDTA和山梨酸钾之间存在显著的交互效应(P<0.01),NISIN和山梨酸钾交互效应不显著(P>0.05)。单因子抑菌效果的顺序依次为NISIN>EDTA>山梨酸钾。     

几种天然保鲜剂对旱地番茄的保鲜效果

研究乳酸链球菌素、魔芋精粉、茶多酚、壳聚糖、海藻酸钠和溶菌酶等天然保鲜剂对旱地番茄保鲜效果的影响,探讨旱地番茄的感官品质、失重率、硬度、可溶性固形物含量、呼吸强度、VC含量、总抗氧化能力等在贮藏过程中生理生化指标的变化。结果表明,与对照组相比,各处理组均不同程度延长了贮藏期。壳聚糖和茶多酚复合处理的旱地番茄,在常温下贮藏15 d后,感官效果最好,呼吸强度显著低于其他组,果实腐烂指数为0.300,失重率为5.60%,硬度降低65.6%,可溶性固形物含量为5.9%, VC含量为12.69 mg/100 g,保鲜效果最佳。     

Stability of monosodium glutamate in green table olives and pickled cucumbers as a function of packing conditions and storage time

The effects of different packing conditions and storage times on the stability of monosodium glutamate (MSG) added to two different fermented vegetables (Spanish-type green table olives and pickled cucumbers) were studied. Factors such as packaging material (glass bottle versus plastic pouch), heat treatment (pasteurisation versus non-pasteurisation), and the presence or not of a preservative compound (potassium sorbate) were considered. The MSG content of pickled cucumbers was stable for up to 1 year of storage in all packing conditions studied. The MSG content also remained stable in pasteurised green table olives. On the contrary, MSG was extensively degraded (>75% degradation) after 54 weeks of storage in unpasteurised green olives with a higher degradation rate in glass bottles compared with plastic pouches. In the presence of potassium sorbate, MSG was also considerably degraded in olives packed in plastic pouches (>50% degradation), but hardly degraded in glass bottles. The results indicate that MSG degradation in olives is due to the action of both lactic acid bacteria and yeasts, with the formation of γ-aminobutyric acid as the major end-product.     

Effect of potassium sorbate and sodium benzoate on microbial population and fermentation of black olives

Black olive fermentation characteristics and diffusion of preservatives into olives were evaluated in brines containing 500 ppm potassium sorbate, 1000 ppm sodium benzoate, 500 ppm sodium benzoate + 250 ppm potassium sorbate and no preservative (control). Changes in brine pH, acidity and microbial population (lactic acid bacteria, yeasts, moulds) were followed during fermentation and storage. Results indicated that K‐sorbate when used at 500 ppm concentration in black olive fermentation had a slight stimulatory effect on the growth of lactic acid bacteria. The yeast counts of brines containing 500 ppm K‐sorbate and 1000 ppm Na‐benzoate were lower than for the brine containing 250 ppm K‐sorbate + 500 ppm Na‐benzoate and for the control with no preservative, while mould growth was completely inhibited in all treatments during fermentation. Mould counts stayed below the detection limit (<10 cfu g⁻¹) during 214 days of vacuum‐packaged storage. Yeast counts showed a progressive decline within 28 days of storage and then stayed relatively constant in all treatments thereafter. The level of yeast population was higher in the control sample than in the sample containing both preservatives during storage. The diffusion of Na‐benzoate and K‐sorbate into the olives after equilibrium was 64% and 80% during fermentation respectively. © 1999 Society of Chemical Industry     

复合防腐剂在常熟叫化鸡加工中的应用

研究了Nisin、山梨酸钾、乳酸钠复合防腐剂对常熟叫化鸡的保鲜效果。通过单因子试验和正交试验,对叫化鸡在不同贮存期作感官评定及菌落总数测定,研究复合防腐剂的保鲜作用。结果表明,乳酸链球菌素、山梨酸钾、乳酸钠添加量分别为0.02%、0.2%、4%时,防腐效果较好。     

复合凝聚法制备枸杞玉米黄质纳米胶囊及其性质研究

本文以宁夏枸杞提取的玉米黄质为芯材,明胶、羧甲基纤维素钠(sodium carboxymethyl cellulose,CMC)作为壁材,利用复合凝聚法制备枸杞玉米黄质纳米胶囊,优化其制备工艺,并对纳米胶囊的性质表征及贮藏稳定性进行研究。结果表明,玉米黄质纳米胶囊的最佳制备工艺为:芯材溶剂浓度0.5%,玉米黄质浓度15 mg/mL芯材溶剂,壁材浓度0.5%,乳化剂浓度0.5%(Tween 80:Span 80=1:1,w/w),固化剂浓度20 U/g明胶。该条件下包埋率为92.60%±2.91%,平均粒径210.7 nm,多分散指数(polydispersity index,PDI)为0.063,Zeta电位为-11.5 mV。显微图像显示其呈现规则的球形结构;X-射线衍射分析结果表明,玉米黄质经包埋后以无定形的状态存在,水溶性得到了改善;贮藏稳定性结果表明,纳米胶囊结构能有效保护玉米黄质,从而抵抗温度、光照、氧气引起的氧化降解,防腐剂山梨酸钾和苯甲酸钠可与玉米黄质纳米胶囊在体系中共存。     

不同防腐剂对烤制鱿鱼片贮藏品质的影响

为了延长烤制鱿鱼片的货架期,本文采用37 ℃加速破坏实验,分别研究空白组、添加山梨酸钾组、添加乳酸链球菌素（Nisin）组及添加ε-聚赖氨酸盐组的烤鱿鱼片样品在贮藏7 d中理化指标的变化,考察贮藏过程中烤制鱿鱼片的TVB-N含量、菌落总数、微观结构、pH、色泽的变化,并对其进行感官评价,探究不同防腐剂对烤制鱿鱼片贮藏品质的影响。结果表明:在贮藏的第7 d,乳酸链球菌素处理的烤制鱿鱼片的TVB-N含量比山梨酸钾组、ε-聚赖氨酸盐组、空白组降低了2.35、8.123、9.612 mg·100 g?1;空白组和山梨酸钾处理组烤制鱿鱼的菌落总数在第5 d时超过标准,分别为4.59、4.48 lg CFU·mL?1,ε-聚赖氨酸盐处理组烤制鱿鱼片的菌落总数在第6 d时超过国家标准,含量为5.08 lg CFU·mL?1。乳酸链球菌素处理组烤制鱿鱼片的菌落总数在贮藏过程中没有超过国家标准。不同防腐剂处理的烤制鱿鱼的色泽、质构和感官评分差异显著（P<0.05）。与ε-聚赖氨酸盐和山梨酸钾相比,乳酸链球菌素能有效的抑制烤制鱿鱼TVB-N含量、菌落总数的上升,且能减缓烤制鱿鱼质构和色泽的变化,使烤制鱿鱼保持良好的感官性状,是更有利于烤制鱿鱼贮藏的防腐剂。     

Effect of preservatives on the functional properties of tapioca starch: analysis of interactions

The effect of different levels of potassium sorbate or sodium benzoate addition on the water sorption behavior and on the mechanical properties of freeze-dried tapioca starch gel was studied.It was observed that the addition of potassium sorbate or sodium benzoate to starch before the gelatinization process increased the amount of water sorbed by the system, but experimental moisture content of the mixture was lower than the one predicted by a mass balance, revealing the existence of an interaction between starch and the preservatives. In general, in the range of water activity 0.755-0.976, most of the preservative was bounded to starch. Mechanical properties of the powder obtained after freeze drying of gels were also influenced by the addition of the preservatives: an increase in bulk density, higher cohesiveness and initial Young modulus was observed after antimicrobial addition.Results obtained showed that sorbate and benzoate interact with tapioca starch and that this interaction has a great influence on system behavior.     

复合生物保鲜剂对缢蛏保鲜效果的研究

缢蛏肉用复合生物保鲜剂处理,进行冷藏(0～2℃)试验,观察其感官指标的变化,测定其在此过程中硫代巴比妥酸(TBA)、游离脂肪酸(FFA)、挥发性盐基氮(TVBN)、Ca2+-ATPase值等生化指标的变化。结果表明： 在冷藏过程中,螠蛏肉使用复合生物保鲜剂处理的保鲜效果明显好于对照组。几种复合生物保鲜剂配方中C组(溶菌酶0.05%、Nisin 0.02%、甘氨酸7%、山梨酸钾0.07%等)保鲜效果最好,可以较长的延长缢蛏肉的货架期。     

Effect of jam processing and storage on total phenolics, antioxidant activity, and anthocyanins of different fruits

BACKGROUND: Fruits have been widely recognised as an excellent source of bioactive phenolic compounds. The purpose of this study was to evaluate the effect of jam processing of strawberry, cherry, apricot, fig and orange on the total phenolics, antioxidant activity and anthocyanins during 5 months of storage at 25 °C. RESULTS: Fresh strawberry had the highest contents of total phenolics (8503.1 mg GAE kg^?1) followed by cherry, apricot, fig and orange, respectively. Jam processing decreased the total phenolics, antioxidant activity, and anthocyanins of all fruits. Total phenolics of jam during storage decreased only in apricot, fig and orange. Fresh strawberry had the highest antioxidant activity (54.88% inhibition) followed by the other fruits. Antioxidant activity did not change in strawberry during jam storage, while there are reductions in the other fruits were observed. Fresh strawberry had the highest anthocyanins (2323.8 mg cya‐3‐glu kg^?1), followed by cherry and the other fruits, respectively. Results showed only a decrease of anthocyanins and pH in apricot and fig jams during 5 months of storage. CONCLUSION: Despite the reduction of these compounds in jam processing, it is considered a good method to maintain them during 5 months of storage. Copyright © 2011 Society of Chemical Industry     

Mathematical Modeling of Microbial Growth in Packaged Refrigerated Orange Juice Treated with Chemical Preservatives

ABSTRACT Microbial flora of refrigerated orange juice was analyzed during storage at 10 °C and the effects of the following factors were discussed: 1) the previous washing process of the orange peel, 2) the different levels of the added preservatives (citric acid, ascorbic acid, potassium sorbate, sodium benzoate), 3) the gaseous permeabilities of the packaging film. Gompertz equation was applied to model molds and yeasts growth for the different treatments and packaging conditions. The washing procedure with sodium hypochlorite extend 2–3 d the storage life of the juice (time to reach microbial counts of 10⁶ CFU/ml) in both packaging films. The use of organic acids and potassium sorbate or sodium benzoate (1.66–6.94 mM) led to storage life values > 11 d in polyethylene and > 20 d in the low gaseous permeability film, maintaining good sanitary conditions.