The use of an antimicrobial citrus vapour to reduce Enterococcus sp. on salad products

Citrus essential oils (EOs) have an antimicrobial effect against a range of food poisoning causing bacteria. A blend of citrus EO vapour against vancomycin resistant (VRE) and vancomycin susceptible (VSE) Enterococcus faecium and Enterococcus faecalis on lettuce and cucumber was assessed. Food samples were subjected to the vapour for 45 s in a 600-L vapour chamber at 25 °C. Microbial counts were taken directly after the foodstuff was removed and at various times thereafter. Results show that the initial load per sample was reduced by 3.69–4.14 log₁₀ and 3.80–4.40 log₁₀ for VRE and VSE strains, respectively; reductions were maintained for 6 h. Sensory panel testing demonstrated that there were no significant changes in taste. Growing demand from changes in legislation, consumer trends and increasing isolation of antibiotic resistant pathogens, means that alternatives to chemical-based bactericides need to be found and the antimicrobial citrus vapour may provide the answer.     

柑橘属果皮渣制备膳食纤维的研究进展

柑橘属果皮渣作为柑橘加工的副产物,其中含有大量的膳食纤维,具有较好的生理功能。本文重点综述柑橘属果皮渣中膳食纤维的化学组成和制备方法,对其理化特性、生理功能的研究情况展开论述,并讨论柑橘属果皮渣膳食纤维在食品工业中的综合利用情况。     

新型柑橘贮藏保鲜剂的研究进展

柑橘类果实在贮藏运输中果实表面易被腐败菌浸染而导致货架期和贮藏时间缩短,柑橘的贮藏保鲜方法一直以来都是业界关注的热点问题。本文介绍几种具有无毒、可生物降解、对环境无污染等特点的新型杀菌保鲜方法,其中包括动植物多糖涂膜保鲜（壳寡糖）、植物源提取物保鲜（精油）、生物保鲜剂（微生物代谢产物槐糖脂和拮抗菌）等处理方法。综合分析不同处理方法对柑橘类果实的贮藏效果及其对腐败菌的抑制作用,并对柑橘类果实采后防腐保鲜技术的发展趋势及其商业化前景进行展望。     

Volatile aroma components and antioxidant activities of the flavedo peel extract of unripe Shiikuwasha (Citrus depressa Hayata)

The flavedo peel extracts of unripe Shiikuwasha (Citrus depressa Hayata) fruits were extracted using steam distillation (SD) or a cold-press (CP) system. Volatile aroma content and composition were determined using gas chromatography (GC) and each compound was identified using gas chromatography-mass spectrophotometry (GC-MS). The major constituents of the extracts were monoterpene hydrocarbons (91.75-93.75%[709.32-809.05 mg/100 g of fresh flavedo peel]) including limonene (43.08-45.13%[341.46-379.81 mg/100 g of fresh flavedo peel]), γ-terpinene (27.88-29.06%[219.90-245.86 mg/100 g of fresh flavedo peel]), and p-cymene (8.13-11.02%[61.47-97.22 mg/100 g of fresh flavedo peel]). The extraction process used was determined to be a decisive factor that affects the composition of key citrus aroma components, as well as the antioxidant activities of the Shiikuwasha fruit. Antioxidant capabilities of the extracts were examined by assay of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and β-carotene bleaching inhibition. The cold-press extraction system may better retain the total phenolic content of the flavedo peel and display superior antioxidant activities, compared to the steam distillation extraction method. PRACTICAL APPLICATION: Shiikuwasha (Citrus depressa Hayata) is a type of small citrus fruit, and has been used as raw material for beverage and food additive productions in Japan. It had a unique aroma composition in which the limonene content of its peels is lower than that of other commonly known citrus peels. The present study detailed the volatile aroma composition, as well as antioxidant capabilities of Shiikuwasha peel extracts of different extraction methods, that are cold-press and steam distillation methods. The results of this study may provide a basis for selection of Shiikuwasha peel extracts in food industry for citrus flavor production.     

Enhancing Safety and Aroma Appealing of Fresh-Cut Fruits and Vegetables Using the Antimicrobial and Aromatic Power of Essential Oils

ABSTRACT:  Microbial and aroma attributes are within the most decisive factors limiting safety and sensory appealing of fresh-cut fruits and vegetables. Alternatively, several plant essential oils (EOs) are constituted of several volatile active compounds and most of them present antimicrobial potential and had different aroma profile. Considering these premises, this hypothesis article states that safety and aroma appealing of fresh-cut produce could be improved with EO treatment. EOs could prevent fresh-cut fruit decay; however, their volatile constituents could be sorbed by the produce, and according to the aroma notes of the antimicrobial oil, sensorial appealing of odor, and flavor of the treated produce might be affected positively or negatively. Specifically, garlic oil is a natural antimicrobial constituted by sulfur compounds, which are responsible for its odor and antimicrobial properties. Besides, fresh-cut tomato is a highly perishable product that needs antimicrobial agents to preserve its quality and safety for a longer period of time. From the sensorial point of view, aroma combination of garlic and tomato is a common seasoning practice in Europe and America and well accepted by consumers. Once the right combination of flavors between the EOs and the fresh-cut produce has been selected, safety and quality of the treated fruit could be improved by adding antimicrobial protection and extra aroma. Therefore, other combinations between EOs and fresh-cut produce are discussed. This approximation could reinforce the trends of natural food preservation, accomplishing the demands of the increasing sector of consumers demanding tasty and convenient fresh-cut produce, containing only natural ingredients.     

柑橘属植物果皮精油抑菌作用研究进展

柑橘属植物果皮精油主要由单萜化合物、倍半萜化合物及含氧衍生物构成。柑橘属植物果皮精油不仅安全、风味较好,还具有广谱抑菌性能,因而可以作为化学杀菌剂的天然替代物。柑橘属植物果皮精油抑菌效果同其萜烯类物质的含氧衍生物有密切关系。精油通过破坏细菌和真菌的细胞结构、影响代谢途径等方式起到抑菌效果。柑橘属植物果皮精油可广泛应用于食品保藏、果蔬真菌病害防治等方面,可采用直接添加、熏蒸或与其他抑菌手段协同使用等方法使其达到抑菌效果。综述了柑橘属植物果皮精油抑菌效果、抑菌机理以及应用等方面,为其在食品中的进一步应用提供参考。     

植物精油对真菌微生物抑制作用的研究进展

随着消费者对绿色产品的要求越来越高,人们开始考虑用天然植物精油作为抑菌剂代替化学合成杀菌剂。精油是从植物中分离的天然杀菌剂,具有对抗多种病原微生物的活性,在抑制真菌病害和减少真菌毒素积累方面具有较好的功效,逐渐被广泛应用于食品防腐保鲜、化妆品、医药等领域。该文综述了不同植物精油的化学组成和抑菌作用,分析了植物精油的抑菌机制,最后讨论了植物精油作为抑菌防霉剂的应用及研究进展,以期为探寻安全的天然抑菌剂提供参考。     

Polymethoxy flavones are responsible for the anti-inflammatory activity of citrus fruit peel

In traditional Chinese medicine, dried citrus fruit peels are widely used as remedies to alleviate some respiratory inflammatory syndromes and are considered as potential sources of anti-inflammatory components. Seven citrus fruits were selected for this study. We determined the inhibitory ability of citrus peel extracts on the production of pro-inflammatory mediators, prostaglandin E₂ (PGE₂) and nitric oxide (NO), in lipopolysaccharide (LPS)-activated RAW 264.7 cells. Among the tested citrus peels, Ponkan (Citrus reticulata Blanco) and Tonkan (Citrus tankan Hayata) deserve special attention due to their outstanding inhibitory effect on PGE₂ and NO secretion. We have also examined the composition, flavanone glycosides and polymethoxy flavones. The polymethoxy flavone content, especially nobiletin, appears to correlate well with the anti-inflammatory activities of certain citrus peel extracts. Thus, our results suggest that polymethoxy flavones contribute crucially to the anti-inflammatory activity of citrus peels.     

14种柑橘皮中多甲氧基黄酮成分分析

建立柑橘皮中9 种多甲氧基黄酮（polymethoxyflavonoids,PMFs）快速定量检测方法,比较不同品种来源柑橘皮中PMFs的含量差异,为寻找高含量PMFs高生物活性柑橘皮的药食两用素材提供参考。采用超声乙醇提取、高效液相色谱方法快速准确检测PMFs,并对14 种柑橘皮、陈皮中9 种特征物质PMFs含量进行比较。结果显示9种PMFs在对照品溶液质量浓度范围内具有良好的线性关系,且准确度和精确度良好。分析发现,不同品种来源柑橘皮中PMFs种类和含量差异很大。江西陈皮、重庆柑橘、广西皇帝柑、广西砂糖橘果皮中PMFs总含量很高,均在7495.19 μg/g以上,其中广西沙糖橘果皮PMFs总含量高达10 412.18 μg/g。该方法简便,稳定性好,可为柑橘皮中PMFs生物活性研究的深入、柑橘皮产品开发和中药原料选材及其质量控制提供科学依据。     

植物精油对果蔬中微生物的抑菌效果及作用机理研究进展

植物精油对引起果蔬腐烂的微生物具有较强的抑制作用,其抑菌机理已成为目前国内外研究的热点问题。本文全面介绍了植物精油对果蔬中微生物的抑制效果、植物精油对微生物的作用机理。植物精油对果蔬中常见微生物具有较强的抑菌效果,主要通过破坏微生物的细胞膜、细胞壁和DNA等结构,影响基因表达、细胞呼吸作用和能量代谢等途径,最终导致微生物细胞死亡。本文还提出植物精油抑菌作用机理研究中存在的问题,以期为精油的研究和应用提供依据。     

Orange Essential Oils Antimicrobial Activities against Salmonella spp.

ABSTRACT:  Seven citrus essential oils (EOs) were screened by disc diffusion assay for their antibacterial activity against 11 serotypes/strains of Salmonella . The 3 most active oils were selected to determine the minimal inhibitory concentration (MIC) against the same Salmonella . Orange terpenes, single-folded d-limonene, and orange essence terpenes all exhibited inhibitory activity against the Salmonella spp. on the disc diffusion assay. EOs were stabilized in broth by the addition of 0.15% (w/v) agar for performance of the MIC tests. Orange terpenes and d-limonene both had MICs of 1%. The most active compound, terpenes from orange essence, produced an MIC that ranged from 0.125% to 0.5% against the 11 Salmonella tested. Gas chromatography-mass spectrometry (GC/MS) analysis revealed that this orange essence oil was composed principally of d-limonene, 94%, and myrcene at about 3%. EOs from citrus offer the potential for all natural antimicrobials for use in improving the safety of organic or all natural foods.     

The inhibitory effect of plant essential oils on foodborne pathogenic bacteria in food

Abstract

In recent years, with the continuous improvement of people's living standard, the importance of healthy lifestyles is becoming more and more recognized. Therefore, food safety has attracted much attention. This has prompted people to study new technologies that can guarantee food safety without the use of preservatives. Compared with other types of food preservatives, essential oils (EOs) are gotten more attention, because they meet the current development trend of food additives about "green", "safety" and "health". Therefore, this paper focuses on the research of effective contribution of EOs to inhibit the growth of foodborne pathogens, systematically summarized the commonly used EOs and their main extraction methods and chemical components and, the antibacterial mechanism of EOs on food borne pathogens, systematically analysis the specific application case of EOs in food discussed. Hoping to provide some reference and help to the relevant researchers.     

柑橘类水果类黄酮化合物的提取及分析方法研究进展

柑橘类水果, 富含多种天然生物活性成分, 尤以类黄酮化合物含量最高, 对某些慢性疾病有预防和控制作用, 故其较多活性成分已应用于食品行业和医药行业等, 这也是近年来柑橘类水果中类黄酮化合物的提取制备方法和分析方法被许多科研工作者高度关注的原因。本文主要介绍了近年来柑橘类黄酮物质的分离提取方法和定性定量分析方法, 为今后研究和开发柑橘类水果的科研工作者提供一定的参考。     

Important flavonoids and limonin in selected Thai citrus residues

The distributions of important flavonoids and limonin in selected Thai citrus residues were investigated in this study. The residues of interest were peels of pomelo (Citrus grandis (L.) Osbeck cv. Kao Yai and cv. Kao Nampheung), residues after juice extraction of tangerine (Citrus reticulata Blanco cv. Sainamphueng and cv. Bangmod) and peels and residues after juice extraction of kaffir lime (Citrus hystrix DC). Flavonoids were characterized and quantified in terms of flavanones, i.e., naringin and hesperidin, and polymethoxyflavones (PMFs), i.e., nobiletin, sinensetin and tangeretin. Naringin was a dominant flavanone in polmelo peels. Three PMFs were found in all samples with varying contents. Comparing the samples, residues from tangerine cv. Bangmod exhibited the highest value of each PMFs. Limonin was present in small amounts in pomelo peels and residues after juice extraction of tangerine and kaffir lime. All samples were good sources of dietary fibre, with a total dietary fibre content of more than 60 g/100 g on a dry weight basis with high proportion of soluble dietary fibre.     

柑橘皮渣生物转化利用研究进展

柑橘皮渣生物转化利用主要转化为燃料乙醇、沼气、饲料、酶制剂、食品和食品添加剂,通过微生物和酶作用,实现资源再利用,这既能提高柑橘副产物利用率,又能开发各种新型生物转化产品。本文就柑橘皮渣生物转化利用的国内外研究现状进行综述,并提出以后的研究方向。     

蜂胶提取物处理对柑橘诱导抗病性的影响

以柑橘为材料,对蜂胶提取物诱导柑橘抗青霉病的表达时间以及蜂胶提取物处理对柑橘果实抗病性相关物质及酶的影响进行研究。结果显示,蜂胶提取物处理后48h 人工接种意大利青霉,柑橘所表现出的抗病性最强。蜂胶提取物处理增加了柑橘果皮中酚类物质的含量,提高了柑橘果皮中苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、多酚氧化酶(PPO)、几丁质酶(CHT)与诱导抗病性密切相关的酶的活性。这表明蜂胶提取物可增强柑橘果实的防御系统,降低果实贮藏期间的发病率,对柑橘表现出良好的保鲜效果。     

植物精油在食品保鲜中的研究进展

植物精油是重要的植物次生代谢产物,由分子量相对较小的简单化合物组成,具有一定芳香气味。由于植物精油具有多种生物活性,作为一种天然保鲜剂在食品保鲜领域的应用越来越广泛。本文介绍了其在水果、蔬菜、肉及肉制品、鱼类产品、乳制品等保鲜领域的应用,并探讨了植物精油在食品保鲜方面存在的问题,并对其发展方向和应用前景作了展望,为植物精油的进一步开发研究及应用提供了依据。     

植物精油蒸气与空气负离子在食品保藏中的应用研究进展

植物精油属于GRAS物质,具有较高的安全性,将其应用到食品的防腐保鲜中可以减少化学合成抗菌剂对人体产生的不良影响。精油的蒸气形式可以在不与食品直接接触的情况下对多种细菌、霉菌和酵母产生抑制作用,其主要抑菌成分为单萜烯和醛类,通过疏水性作用于细胞达到抗菌效果。植物精油蒸气与食品包装相结合,可以降低精油对于食品感官的影响并为食品提供抑菌保护。空气负离子能提高精油蒸气对微生物细胞的破坏作用,高浓度的空气负离子还能抑制微生物的活性,将精油与空气负离子结合使用,可以把对食品品质的影响降到最低,并提供更好的抑菌效果。     

两种微波装置提取柑橘皮总黄酮的工艺比较

分别利用微波化学反应器(简称微化装置)和微波消解/萃取系统(简称微消装置)提取柑橘皮总黄酮。通过L9(34)正交实验设计,以固液比、乙醇浓度、提取时间、微波功率(微化装置)或提取温度(微消装置)为考察因素,分别优化并比较了2种微波装置的提取工艺。微化装置最佳提取工艺条件为:固液比1:30,70%乙醇作提取剂,于240W下微波提取2.0min,此时总黄酮得率为4.72mg/g;微消装置最佳工艺条件为:固液比1:20,70%乙醇作提取剂,于160℃下微波萃取3.0min,此时总黄酮得率为9.15mg/g,得率约为前者的2倍。分析讨论了微消装置得率较高的原因,分别应用2种微波装置提取3个不同品种的柑橘皮样品。结果表明:微消装置提取柑橘皮总黄酮较常规微波辅助提取法更为有效,可用于高效、快速、简便地提取天然产物有效成分。     

Phytochemical characteristics of citrus peel and effect of conventional and nonconventional processing on phenolic compounds: A review

Citrus peel is rich in functional ingredients such as essential oils (0.6–1%), fibers (6.30–42.13 g/100 g db), phenols (0.67–19.62 g/100 g db), and vitamin C (0.109–1.150 g/100 g db). Flavanones (hesperidin: 0.002–80.90 mg/g db, neohesperidin: 0.05–11.70 mg/g db, narirutin: 0.03–26.90 mg/g db; naringin: 0.08–14.40 mg/g db), and polymethoxylated flavones (sinensetin: 0.08–0.29 mg/g db, nobiletin: 0.20–14.05 mg/g db, tangeretin: 0.16–7.99 mg/g db) are the main phenolic compounds (PCs) of citrus peel. Due to their antioxidant activity, PCs are used in various applications such as formulation of healthy food, cosmetic, and pharmaceutical products. PCs present sensitivity to process operating conditions (during juice processing and further thermal and nonthermal processing). This review summarizes the main publications dealing with the proximate chemical composition, the functional properties, and the potential applications of the main citrus peel compounds. The effects of conventional and nonconventional processing on PCs of citrus fruits and their derived and coproducts are analyzed. The information provided in this review allows a better choice of appropriate processes and their optimal operating conditions for a better retention of antioxidants in citrus products.