肉桂醛、柠檬醛抗黄曲霉作用的研究

目的:研究肉桂醛、柠檬醛的抗黄曲霉作用。方法:在含不同浓度药物的蔡氏培养液中接种一定量的黄曲霉孢子,每隔 4h分别取定量培养液涂布于蔡氏培养皿上进行霉菌计数,直到48h。 26.5℃培养 72h后计数萌发的霉菌孢子;用扫描电镜观察药物作用后黄曲霉的形态、表面结构的变化。结果:与对照组比较,肉桂醛、柠檬醛的浓度分别在≥0.05μg/ml、0.28μg/ml作用4h后,萌发的黄曲霉孢子数明显减少;肉桂醛、柠檬醛作用后黄曲霉孢子菌丝的形态、表面结构明显改变。结论:肉桂醛、柠檬醛对黄曲霉孢子萌发有显著的抑制作用,柠檬醛抑制黄曲霉孢子的萌发更迅速,两者可能通过破坏真菌细胞结构起抗菌作用。     

牛至油、香芹酚、柠檬醛和肉桂醛抗真菌研究

采用纸片扩散法以及双倍稀释法研究牛至油、香芹酚、柠檬醛和肉桂醛对面包酵母和黑曲霉的抑菌效果、最小抑菌浓度(CMIC)和最小杀菌浓度(CMFC)。结果表明,牛至油、香芹酚、柠檬醛和肉桂醛对面包酵母和黑曲霉均有明显的抑制作用。抑菌效力相比较,对面包酵母的抑制效果:肉桂醛>香芹酚>牛至油>柠檬醛;对黑曲霉的抑制效果:香芹酚>牛至油>肉桂醛>柠檬醛。因此,牛至油、香芹酚、柠檬醛和肉桂醛可以作为天然抑菌剂应用于食品加工中。     

茶多酚、柠檬醛和肉桂醛对食源菌生物被膜的影响研究

研究茶多酚、柠檬醛、肉桂醛在亚抑菌浓度下对食源性金黄色葡萄球菌和肠炎沙门氏菌生物被膜形成能力的影响.采用二倍稀释法确定三种物质的最小抑菌浓度,在亚抑菌浓度下作用于10株金黄色葡萄球菌和10株肠炎沙门氏菌,用微孔板法检测两种细菌生物被膜形成情况.结果表明茶多酚、柠檬醛、肉桂醛在亚抑菌浓度下对金黄色葡萄球菌和肠炎沙门氏菌均有不同程度的抑制作用,差异有统计学意义(P＜0.05),且随着各物质浓度的加大抑制作用也增强,茶多酚对革兰氏阳性菌金黄色葡萄球菌成膜抑制能力比对革兰氏阴性菌肠炎沙门氏菌的成膜抑制能力要强,差异有统计学意义(P＜0.05).柠檬醛和肉桂醛对两种不同细菌的成膜抑制能力没有差异.     

β-环糊精包埋丁香酚、肉桂醛、柠檬醛缓释防腐包在传统肉干上的防霉效果对比

将具有抗菌活性的丁香酚、肉桂醛、柠檬醛用β-环糊精包埋后制成抗菌活性缓释防腐包,应用于传统肉干的保藏,通过观察肉干贮藏过程中霉变情况,研究其应用效果。本文根据肉干干燥过程特性,确定了肉干贮藏较适宜的水分含量为16.40%,水分活度为0.695,将此水分肉干作为样品,于28℃贮藏6个月后,未加入防腐包的空白对照组肉干28 d开始长出霉菌,而包合物添加量在2.0 g以上的丁香酚、肉桂醛、柠檬醛缓释防腐包的肉干组6个月均未长霉,具有较好的防霉变效果,但低于2.0 g防腐包添加量时,肉干贮藏一个月后,陆续长出霉菌,此时防腐效果为丁香酚>柠檬醛>肉桂醛。     

牛至油对奶牛产奶性能和抗氧化功能影响的研究

试验通过添加牛至油来观察其对奶牛的产奶性能及抗氧化功能的影响。对照组饲喂基础日粮,试验组在基础日粮中添加15g质量分数为10%的牛至油预混剂,连续饲喂30d。结果表明:乳脂率提高7. 57% (P<0. 05),产奶量和乳蛋白率差异不显著(P>0. 05);血清SOD和GSH-Px活性分别提高6. 97%和10. 86% (P<0. 05 ),血清MDA含量下降7. 94% (P<0. 05)。牛至油可以提高牛奶乳脂率含量和增强抗氧化功能。     

香芹酚抗氧化和抑制酪氨酸酶活性的研究

采用清除DPPH、ABTS、羟自由基和超氧自由基,抑制脂质过氧化活性和抑制酪氨酸酶活性的方法,检测香芹酚的抗氧化活性和抑制酪氨酸酶活性。实验结果显示,香芹酚具有明显的抗氧化活性和抑制酪氨酸酶活性,呈浓度依赖性效应。在清除DPPH、ABTS、羟自由基、超氧自由基,抑制脂质过氧化活性和抑制酪氨酸酶活性试验中,香芹酚的体系终浓度IC50分别为100μmol/L、18.18μmol/L、16μmol/L、16μmol/L、12.5μmol/L和6.67μmol/L。作为阳性对照药物的山奈酚的体系终浓度IC50分别为80μmol/L、9.09μmol/L、12μmol/L、12μmol/L、8.33μmol/L和3.33μmol/L。香芹酚具有1个酚羟基,山奈酚具有3个酚羟基,分子结构的不同,导致山奈酚和香芹酚抗氧化活性和抑制酪氨酸酶活性不同。研究表明香芹酚具有明显的抗氧化活性和抑制酪氨酸酶活性,是值得进一步研究的抗氧化防衰老类候选药物、化妆品原料和食品添加剂。     

埃洛石纳米管负载香芹酚及其性能的研究

为提高食品包装系统的抗菌效率,利用真空负压法将挥发性的香芹酚封装在埃洛石纳米管中,制备香芹酚-埃洛石纳米管包合物.采用FTIR、TEM、TG、UV光谱仪、DSC分析包合物的成份、微观结构形貌、载药率和热稳定性,琼脂平板计数法研究包合物的抗菌性能.结果表明:包合物中香芹酚最大载药量为20％;包合物含量为8％(w/w)的玉...     

改性β-环糊精对茴香醛、柠檬醛的包结研究

采用羟丙基化改性的β-环糊精（β-CD）对茴香醛和柠檬醛进行了包结研究,考察了包合反应的影响因素。结果表明,在水用量为15mL/g改性β-CD的水溶液中,改性β-CD与茴香醛或柠檬醛的摩尔比为1:1、包合反应时间为90min时,茴香醛和柠檬醛的包合率均大于98%。所得产品经紫外光谱、薄层色谱和红外光谱法鉴定为改性β-CD与茴香醛或柠檬醛的包合物。与β-CD比较,改性β-CD对柠檬醛、茴香醛的包合能力明显增强。      

改性β-环糊精对茴香醛、柠檬醛的包结研究

采用羟丙基化改性的β-环糊精(β-CD)对茴香醛和柠檬醛进行了包结研究,考察了包合反应的影响因素。结果表明,在水用量为15mL/g改性β-CD的水溶液中,改性β-CD与茴香醛或柠檬醛的摩尔比为1:1、包合反应时间为90min时,茴香醛和柠檬醛的包合率均大于98%。所得产品经紫外光谱、薄层色谱和红外光谱法鉴定为改性β-CD与茴香醛或柠檬醛的包合物。与β-CD比较,改性β-CD对柠檬醛、茴香醛的包合能力明显增强。     

柠檬醛纳米乳对壳聚糖涂膜性能和保鲜效果的影响

为全面地探究柠檬醛纳米乳/壳聚糖复合涂膜对柑橘果实的保鲜机理,研究首先表征了柠檬醛纳米乳添加量(10%、20%和30%,质量分数)对壳聚糖平板膜拉伸性能和透过性能,以及膜液在果实表皮润湿性能的影响,然后测定了复合涂膜对蜜桔果实贮藏品质的影响。结果表明,柠檬醛纳米乳可增强壳聚糖膜的塑性,提高薄膜的水蒸气透过系数与氧气透过系数;添加10%的纳米乳使得涂膜液在蜜桔果皮表面的接触角由纯壳聚糖膜液的80.49°降至66.2°,铺展系数则由-53.48 mN/m提升至-23.02 mN/m,较好地改善了涂膜液对蜜桔果皮的润湿性,提高了二者的界面相互作用。将柠檬醛纳米乳/壳聚糖复合涂膜用于蜜桔保鲜时,可较好地抑制果实的腐烂,降低其呼吸强度并维持较为稳定的营养物质含量。其中,纳米乳添加量为20%的涂膜对果实腐烂的抑制效果最好,贮藏19 d后该组果实的腐烂率仅为16.67%,而对照组的腐烂率已超过30%。因此,柠檬醛纳米乳的添加既可提高涂膜在果皮表面的铺展性能以改善涂膜结构,同时也可通过柠檬醛的释放来减少微生物对果实的侵染,进而显著提高果实的贮藏品质,在果实采后保鲜中具有良好的应用潜力。     

Antioxidant activity of essential oil of oregano species from Argentina in relation to their chemical composition

The purpose of this work was to determine chemical composition and antioxidant activity of essential oil of different oregano species from Argentina: ‘Cordobes’, ‘Criollo’, ‘Mendocino’ and ‘Compacto’. The essential oil composition was determined by gas–liquid chromatography and mass spectrometry. Scavenging activity was analysed by DPPH test. The antioxidant activity of the essential oils was determined by an accelerated oxidation test in canola oil. Thirty‐nine compounds were identified in the oregano essential oils. The oregano species showed differences in their chemical composition, radical scavenging activity and antioxidant activity. The main compounds in the studied oregano species were thymol and trans‐sabinene hydrate followed by γ‐terpinene, terpinen‐4‐ol and α‐terpinene. The oregano, ‘Criollo’, was rich in γ‐terpinene and had lower thymol and trans‐sabinene hydrate and higher α‐terpinene and carvacrol contents than the other oregano species. ‘Mendocino’ had higher trans‐sabinene hydrate and limonene than the other oregano species. ‘Cordobes’ and ‘Compacto’ had higher thymol content, radical scavenging activity and antioxidant activity in canola oil.     

Inactivation of Listeria monocytogenes on ham and bologna using pectin-based apple, carrot, and hibiscus edible films containing carvacrol and cinnamaldehyde

Edible films can be used as wrapping material on food products to reduce surface contamination. The incorporation of antimicrobials into edible films could serve as an additional barrier against pathogenic and spoilage microorganisms that contaminate food surfaces. The objective of this study was to investigate the antimicrobial effects of carvacrol and cinnamaldehyde, incorporated into apple, carrot, and hibiscus-based edible films against Listeria monocytogenes on contaminated ham and bologna. Ham or bologna samples were inoculated with L. monocytogenes and dried for 30 min, then surface wrapped with edible films containing the antimicrobials at various concentrations. The inoculated, film-wrapped samples were stored at 4 °C. Samples were taken at day 0, 3, and 7 for enumeration of surviving L. monocytogenes by plating on appropriate media. Carvacrol films showed better antimicrobial activity than cinnamaldehyde films. Compared to control films without antimicrobials, films with 3% carvacrol induced 1 to 3, 2 to 3, and 2 to 3 log CFU/g reductions on ham and bologna at day 0, 3, and 7, respectively. Corresponding reductions with 1.5% carvacrol were 0.5 to 1, 1 to 1.5, and 1 to 2 logs, respectively. At day 7, films with 3% cinnamaldehyde reduced L. monocytogenes population by 0.5 to 1.5 and 0.5 to 1.0 logs on ham and bologna, respectively. Inactivation by apple films was greater than that by carrot or hibiscus films. Apple films containing 3% carvacrol reduced L. monocytogenes population on ham by 3 logs CFU/g on day 0 which was 1 to 2 logs greater than that by carrot and hibiscus films. Films were more effective on ham than on bologna. The food industry and consumers could use these films to control surface contamination by pathogenic microorganisms. PRACTICAL APPLICATION: Antimicrobial edible, food-compatible film wraps prepared from apples, carrots, and hibiscus calyces can be used by the food industry to inactivate Listeria monocytogenes on widely consumed ready to eat meat products such as bologna and ham. This study provides a scientific basis for large-scale application of edible fruit- and vegetable-based antimicrobial films on foods to improve microbial food safety.     

Antioxidant efficiency of oregano during frying and storage of potato chips

The effect of oregano on the oxidative stability of cottonseed oil during frying of potato chips and on the storage stability of the produced chips was studied. The ground spice or an ethanol‐derived extract thereof was added to the oil at a concentration of 2 g l^?1 (dry basis) before frying. The results showed that both ground oregano and its ethanol‐derived extract decreased the rates of accumulation of conjugated dienes, polar compounds, polymerised triglycerides, dimeric triglycerides as well as p‐anisidine value (p‐AV) of the frying oil. The major decrease was observed in the accumulation of polymerised and dimeric triglycerides. The accumulation of oxidised triglycerides showed a low decrease with the addition of oregano, while the hydrolytic compounds formed during frying were not affected. No significant difference (at 95% significance level) between ground oregano and its ethanol‐derived extract was observed. The storage stability of potato chips removed from the fryer at various time intervals was estimated by the rates of increase in peroxide value and conjugated dienes of the oil absorbed in the chips. Both rates were depressed when oregano was added to the frying oil; the protective action of oregano extract was considerably greater (at 95% significance level) than that of ground oregano. Copyright © 2003 Society of Chemical Industry     

Chemical stability of extra-virgin olive oil added with oregano essential oil

Extra virgin olive oil is highly consumed and well known for its nutritional and health benefits. However, it is fatty food highly susceptible to lipid oxidation. The objective of this study was to evaluate the preserving effect of oregano (Origanum vulgare L. spp vulgare called "oregano compacto") essential oil on physical and chemical properties in extra virgin olive oil during storage. Oregano essential oil composition was analyzed by GC-MS. This essential oil was added into extra virgin olive oil at 0.05%. The samples were stored in 3 different conditions: darkness, light exposure, and temperature (60 °C). Chemical indicators of lipid oxidation (peroxide value, p-anisidine value, conjugated dienes, free fatty acidity, and carotenoid and chlorophyll contents) were measured. High content in carvomenthol (22.52%), terpinolene (19.77%), thymol (13.51%), and γ-terpinene (10.30%) were detected in oregano essential oil. Olive oil samples without oregano essential oil stored at 60 °C and exposure at artificial light had the highest peroxide values during storage. Higher p-anisidine and K232 values after day 7 of storage were detected in temperature, darkness, and light exposure treatments. Light treatment was the main factor that degraded chlorophyll causing loss of color. The highest chlorophyll content (3.87 mg/kg) was observed in olive oil with essential oil at the end of storage. In general, olive oil samples added with oregano essential oil had lower peroxide, conjugated dienes, and p-anisidine values and higher chlorophyll and carotenoid contents during storage. Oregano essential oil retards lipid oxidation process in olive oil prolonging its shelf life. PRACTICAL APPLICATION: Oregano essential oil was and is used with the purpose of flavoring and aromatizing food. This essential oil due to its composition has shown antioxidant activity. Synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are thought to be promoters of carcinogenesis. Extra virgin olive oil is widely consumed because of its nutritional benefits and sensory properties which are very important to be preserved in the product. In this study, the oregano essential oil showed remarkable antioxidant activity in olive oil. Therefore, this essential oil could be considered for the industry as natural antioxidant not only to be used in olive oil but also in other fatty food products to substitute synthetic ones.     

Antioxidant activities of Thai pigmented rice cultivars and application in sunflower oil

An analytical comparison for active chemical compounds and their antioxidant activities between three representative pigmented Thai rice cultivars was performed. It was revealed that the darkest purple‐red cultivar (Kum Doi Musur, KDM) contained the highest total phenolic content of 1164.6 mg gallic acid equivalent per100 g (dry basis, db) and the highest total monomeric anthocyanin content of 381.7 mg per100 g (db), when compared with the purple cultivar (Riceberry) and the red cultivar (Sungyod). Its 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging activity and ferric reducing antioxidant power were also the highest. When applied in sunflower oil, the KDM crude extract was efficiently capable of retarding lipid peroxidation as assessed by peroxide value, p‐anisidine value, totox value and the Rancimat method. Results show this specific pigmented rice to be a potent antioxidant for stabilisation of sunflower oil.     

In vitro degradation and in vivo passage kinetics of carvacrol,thymol, eugenol and trans‐cinnamaldehyde along the gastrointestinal tract of piglets

BACKGROUND: The essential oils (EO) carvacrol, thymol, eugenol and trans‐cinnamaldehyde have well‐documented antimicrobial properties and offer therefore an alternative for the antimicrobial growth promoters in pig feeds. The aim of this work was to determine the degradation and kinetics of these EO along the gastrointestinal tract (GIT) of piglets, which is necessary information for correct application in pig feeds. RESULTS: None of these compounds was significantly degraded in in vitro simulations of pig gastric fermentation. Carvacrol and thymol were not degraded in jejunal simulations, but significant losses of up to 29% were found in caecal simulations. Eugenol and trans‐cinnamaldehyde showed a more pronounced degradation in jejunal and caecal simulations. A single dose mixed with feed (13.0, 13.2, 12.5 and 12.7 mg kg^?1 body weight for carvacrol, thymol, eugenol and trans‐cinnamaldehyde respectively) was given orally to piglets. Half‐lives in total digestive tract ranged between 1.84 and 2.05 h, whereby trans‐cinnamaldehyde showed the fastest disappearance. All of these EO were mainly and almost completely absorbed in the stomach and the proximal small intestine. Plasma concentrations (sum of free and conjugated compound) peaked at 1.39, 1.35 and 0.83 h for carvacrol, thymol and eugenol respectively and this was accompanied by high concentrations in urine. CONCLUSION: The four compounds were in vitro poorly degraded in the proximal segments of the GIT of piglets, but degradation is expected in more distal segments. In vivo, the EO were mainly and almost completely absorbed in the stomach and the proximal small intestine. Copyright © 2008 Society of Chemical Industry     

日粮中添加牛至精油改善牛肉熟化过程中的肉品质

为研究日粮中添加牛至精油对牛肉熟化过程中食用品质的影响,选择10头体重相近、健康无疾病的荷斯坦奶公牛,随机平均分成实验组(添加牛至精油)和对照组(未添加牛至精油),相同环境下饲喂8个月后屠宰,测定肉品质。结果显示:熟化时间和牛至精油对肉色变化存在互作效应(p<0.05)。熟化0 d实验组亮度(L*)、黄度(b*)显著低于对照组(p<0.05),红度(a*)低于对照组(p>0.05);熟化第7 d,红度有显著高于对照组的趋势(p<0.10);在熟化过程中,剪切力、失水率、蒸煮损失均低于对照组(p>0.05),熟肉率均高于对照组(p>0.05),p H变化较对照组稳定。该结果提示在日粮中添加牛至精油,一方面可以更长时间保持肉的红色度,显著降低亮度、黄度,维持p H稳定,另一方面,可以改善嫩度,降低失水率和蒸煮损失,提高熟肉率,改善牛肉品质。      

Development of PLA films containing oregano essential oil (Origanum vulgare L. virens) intended for use in food packaging

Consumers’ concerns about the environment and health have led to the development of new food packaging materials avoiding petroleum-based matrices and synthetic additives. The present study has developed polylactic acid (PLA) films containing different concentrations of essential oil from Origanum vulgare L. virens (OEO). The effectiveness of this new active packaging was checked for use in ready-to-eat salads. A plasticising effect was observed when OEO was incorporated in PLA films. The rest of the mechanical and physical properties of developed films did not show much change when OEO was included in the film. An antioxidant effect was recorded only for films containing the highest percentages of the active agent (5% and 10%). In addition, films exhibited in vitro antibacterial activity against Staphylococcus aureus, Yersinia enterocolitica, Listeria monocytogenes, Enterococcus faecalis and Staphylococcus carnosus. Moreover, in ready-to-eat salads, antimicrobial activity was only observed against yeast and moulds, where 5% and 10% of OEO was the most effective.