Evaluation of antioxidant activities of Iranian sumac (R. coriaria L.) fruit and spice extracts with different solvents

The antioxidant capacity and phenolic content of three sumac (Rhus coriaria L.) samples, including brown sumac fruit, brown sumac powder and red sumac powder were investigated in the present study. Methanol, ethanol, distilled water, and a mixture of methanol and ethanol (1:1) were used as solvent systems. Antioxidant activities of extracts were screened using 1,1-diphenyl-2-picrylhydrazyl DPPH radical scavenging method. Phenolic content was determined through Folin–Ciocaltaeu procedure. The efficiency of the solvents used to extract phenols from the samples varied considerably. The phenolic content of brown sumac powder ranged from 2.906 to 2.997 gallic acid equivalents/100 g (GAE/100 g), while that of the brown sumac fruit was 2.438–2.529 GAE/100 g, and that of the red sumac powder was 2.172–2.263 GAE/100 g. Findings indicated that water extracts of sumac have effective antioxidant and radical scavenging activities as compared to other extracts.     

Effects of methanolic extract of sour cherry (Prunus cerasus L.) on microbial growth

The antimicrobial activity of a methanolic extract of the common edible fruit Prunus cerasus L. was evaluated. HPLC analysis of the extract revealed the abundant presence of anthocyanins. Minimum Inhibitory Concentrations (MIC) for Gram‐positive and Gram‐negative pathogenic bacteria was in the range 2–6.6 mg mL^?1, whereas the time‐kill assay revealed that the bactericidal effect was exerted only at concentrations higher than 2× MIC. Interestingly, at concentrations lower than MIC, P. cerasus L. extract exerted a stimulating effect on bacterial proliferation and on the ability to form biofilms. In particular, a multidrug‐resistant Acinetobacter baumannii strain showed a 30% increase in growth at low concentrations. In the light of this finding, we speculate that the use of berry extracts (rich in anthocyanins) may present some risks to human health when used as preservatives in food and cosmetic products.     

Evaluation of reducing power and radical scavenging activities of water and ethanol extracts from sumac (Rhus coriaria L.)

The purpose of this study was to determine the reducing power, metal chelating, and radical scavenging capabilities of water and ethanol extracts of sumac (Rhus coriaria L.), comparatively. The water and ethanol extracts of sumac were evaluated for their radical scavenging activities by means of the DPPH and DMPD assays. Water extract of sumac (R. coriaria L.) scavenged radicals effectively with EC₅₀ values of 36.4 ??g/ml for DPPH free radical and 44.7 ??g/ml for DMPD cation radical. Similarly, the total reducing power of water extract was found higher than ethanol extract in both potassium ferricyanide reduction (FRAP) and cupric ions reduction capacity methods (CUPRAC). 2,2′-Bipyridine was used to determine the metal chelating activity and the result of water extract was found higher than ethanol extract. Total phenolic and total flavonoid contents of both extracts were studied as well. The values of water extract were found to be higher than that of ethanol extract. The present study found that water extracts of sumac (R. coriaria L.) have effective antioxidant and radical scavenging activities as compared to ethanol extracts.     

电子束辐照对鲜切青椒表面食源性致病菌杀灭效果的研究

研究了高能电子束辐照对鲜切青椒表面食源性致病菌的杀灭效果,为电子束在提高青椒等鲜切类蔬菜食用安全性领域的应用提供理论及实践依据。鲜切青椒经0.5、1、1.5、2、2.5kGy等不同剂量电子束处理以及酸化亚氯酸钠(ASC)结合1kGy处理、柠檬酸(C)结合1kGy处理后,置于4℃的冰箱中贮藏,并在辐照后的第0、3、6、9、12d对三种食源性致病菌进行计数,同时测定了不同处理方式对鲜切青椒感官品质的影响。实验结果表明,ASC结合1kGy辐照处理不仅能够有效地杀灭鲜切青椒表面的食源性致病菌,而且不会影响其品质。      

Composition analysis and immuno-modulatory effect of okra (Abelmoschus esculentus L.) extract

The aim of this study was to analyse the composition of okra (Abelmoschus esculentus L.) extract and investigate the effect of A. esculentus L. polysaccharides (AE-PS) on the maturation and function of dendritic cells (DCs) derived from rat bone marrow hematopoietic cells (BMHCs) in vitro. BMHC-derived immature DCs (BMHC-imDCs) were extracted from rats and treated with AE-PS. The hydrolysed okra extract contained 0.6% β-1, 3-d-glucan. AE-PS induced the presence of polymorphic nuclei and elongated protrusion in the BHMC-imDCs, indicating DC activation. Treatment with100 μg/mL of AE-PS increased the MHC class II and CD80/86 expression levels by 41% and 42%, respectively. Treated cells had reduced endocytosis activity. The secretion of IL-12 and IFN-γ increased significantly by 120% and 75%, respectively, when treated with 100 μg/mL of AE-PS. Moreover, IL-10 production was reduced by 66%. In conclusion, AE-PS exhibits stimulatory effects on rat dendritic cells and promotes the secretion of T_H1 cytokines.     

Inhibitory effect of kiam (Cotylelobium lanceotatumcraih.) wood extract on gram-positive food-borne pathogens and spoilage micro-organisms

Water extract from kiam (Cotylelobium lanceotatumcraih.) wood was investigated for inhibitory and lethal activity against pathogenic bacteria and micro-organisms isolated from sugar palm sap. Bacteria representing six generaAcetobacter,Flavobacterium,Lactobacillus,Leuconostoc,MicrococcusandSaccharomycesisolated from sap were inhibited on agar media to which a 0.2% (wt/v) water extract of kiam wood saw dust was applied. Extract inhibited growth ofListeria monocytogenes, toxigenicStaphloccoccus aureusand enterotoxigenicBacillus cereusbut not enterohemorrhagicEscherichia coli0157:H7 orSalmonella. The behavior ofL. monocytogenesinoculated onto shredded raw cabbage which was then treated with 0, 0.5 or 5% solutions of wood kiam extract and subsequently stored at 5°C for up to 5 days was determined. Populations of aerobic mesophiles and psychrotrophic micro-organisms were also monitored. Significantly (P=0.05) reduced populations ofL. monocytogeneswere detected in cabbage treated with 0.5 or 5.0% extract and held for 2 or 5 days. Treatment with kiam extract retarded the rate of growth of aerobic mesophiles and psychrotrophic micro-organisms naturally present on cabbage. Treatment with 5.0% extract had a sustained lethal effect during a 5 day test period. Further research is warranted to characterize the compound(s) in kiam wood extract responsible for inhibitory or lethal activity against spoilage micro-organisms and other pathogenic bacteria that may be present in foods.     

Flavonol content in the water extract of the mulberry (Morus alba L.) leaf and their antioxidant capacities

Abstract: The biological activities of the mulberry (Morus alba L.) leaf have been attributed to its flavonoid content. The water extract of the mulberry leaf (WEML) was prepared by autoclaving at 121 °C for 15 min, and the flavonol content of the WEML was determined by HPLC The WEML contained 4 flavonols in the following order: quercetin‐3‐β‐D‐glucose (QT‐G) > quercetin‐3‐O‐glucose‐6″‐acetate (QT‐GA) > rutin (RT) > quercetin (QT). In the oxygen radical absorbance capacity (ORAC) assay, QT had the highest peroxyl radical‐scavenging capacity and a similar hydroxyl radical‐scavenging capacity as its glycosides (QT‐G, QT‐GA, and RT). QT exhibited a stronger cellular antioxidant capacity (CAC) against 2,2′‐Azobis(2‐amidinopropane) dihydrochloride (AAPH)‐ and Cu²⁺‐induced oxidative stress in HepG2 cells compared to its glycosides, indicating that the intracellular antioxidant capacity of QT and its glycosides may depend upon both the permeability across the cell membrane and the peroxyl or hydroxyl radical‐scavenging capacity. Practical Application: The information presented might be used for developing mulberry leaf‐based functional foods.     

Investigation of the effect of sumac extract and BHT addition on the quality of sucuk (Turkish dry‐fermented sausage)

The effect of sumac extract and BHT (butylated hydroxytoluene) addition on the quality (pH, colour, biogenic amine, TBARS values and sensory attributes) of sucuk (Turkish dry‐fermented sausage) were investigated during the ripening period. Addition of BHT decreased the TBARS value by about 23.7%, whereas sumac extract decreased it by 42.0%. Sumac extract decreased (P < 0.05) putrescine formation more than BHT addition. However, no significant difference (P > 0.05) was observed in histamine formation for both the sumac extract and BHT‐added recipe. The highest tyramine concentration was observed in a control recipe (R1) prepared without any antioxidants, and the lowest was in the sumac extract‐added recipe (R3) with mean values of about 96.62 and 63.17 mg kg^?1, respectively. The control recipe (R1) was found to be the worst (P < 0.05) sample with respect to overall sensory quality and addition of either sumac extract or BHT increased (P < 0.05) the overall sensory quality of sucuk. The pH and colour attributes of sucuk were not significantly different (P > 0.05) between the addition of sumac extract and BHT. This study demonstrated that sumac extract had more effect on the quality of sucuk during the ripening period, hence it could be easily utilised in sucuk to enhance quality. Copyright © 2006 Society of Chemical Industry     

Antibacterial activity of the extracts from the fruit rinds of Garcinia cowa and Garcinia pedunculata against food borne pathogens and spoilage bacteria

The crude hexane and chloroform extracts from the fruit rinds of Garcinia cowa and Garcinia pedunculata were studied for their antibacterial activity against some foodborne pathogens and spoilage bacteria such as Bacillus cereus, Bacillus coagulans, Bacillus subtilis, Staphylococcus aureus and Escherichia coli. The minimum inhibitory concentrations (MICs) of the extracts determined by the agar dilution method were ranging from 15 to 500 μg/ml and 300 to 1250 μg/ml for G. cowa and G. pedunculata, respectively. However, the hexane and chloroform extracts from the fruit rinds of G. cowa exhibited marked inhibitory effect against all the test organisms and were more effective than that of G. pedunculata extracts. The antibacterial activity of all the extracts was more pronounced against the tested Gram-positive bacteria than the tested Gram-negative bacterium. Furthermore, this study is the first report on the in vitro antibacterial activity of extracts from the fruit rinds of G. cowa and G. pedunculata.     

竹笋汁对食品腐败菌的抑菌效果研究

研究了竹笋汁对几种常见的食品腐败菌的抑菌作用.结果表明,竹笋汁对蜂蜜酵母菌的抑制效果明显;对细菌和霉菌的抑制效果较差.对假丝酵母和蜂蜜酵母的最低抑菌浓度均为50%(体积分数,相对于100%原液),其最佳抑菌pH值为4,随着pH值的增加抑菌活性下降.竹笋汁的热稳定性较差,经121℃处理25min后,已基本丧失其抑菌活性.     

Impact of germination on the chemical components and bioactive properties of adlay (Coix lachryma‐jobi L.) water extract

In recent years, adlay water extract and related products have been widely consumed. This study investigated the chemical components and bioactive properties of adlay water extract at different germination stages. Glucose and maltose were significantly increased, whereas fructose was slightly decreased after germination. The contents of vitamins C and B₁ in the water extract increased 1.61‐ and 2.68‐fold, respectively. The amounts of peptides, especially those with a molecular weight under 3000 Da, were significantly increased after germination. During germination, the level of total free amino acids rose from 54.09 to 128.22 μg mL^?1, and the percentage of essential amino acids was elevated from 21.63% to 42.13%. Germination also substantially augmented the total phenolic content and antioxidant activity of the water extract. Moreover, the germinated adlay water extract showed higher inhibitory activity on angiotensin‐converting enzyme (ACE), xanthine oxidase and tyrosinase than the water extract of nongerminated adlay. These findings revealed that germination might be a potential way to improve the nutritional value and bioactive properties of adlay water extract.     

Inhibitory effect of Cynara cardunculus L. extract on aflatoxin B1 production by Aspergillus parasiticus in sesame (Sesamum indicum L.)

Aflatoxin B₁ has been considered as the most potent liver carcinogen for humans. One factor that stimulates the production of aflatoxins in oilseed products, such as sesame seeds and their products is the presence of high levels of fatty acids. This work presents further evidence that sesame is a favorable substrate for aflatoxin B₁ production by Aspergillus parasiticus. Moreover, the use of wild artichoke (Cynara cardunculus L.) extract was examined showing inhibition of aflatoxin B₁ production in both sesame and yeast extract sucrose medium, inoculated with A. parasiticus. More specifically, the inhibition of aflatoxin B₁ production by A. parasiticus in sesame seeds paste was 99.6% and in yeast extract sucrose medium it was 99.4%.     

Inhibitory effect of Melastoma candidum D. Don acetone extract on foodborne pathogenic bacteria survival in food products

Melastoma candidum D. Don, a Taiwanese folk medicinal plant, has high levels of antibacterial and bactericidal activity. Our aim was to determine whether and to what extent an acetone extract of this plant inhibits the growth of foodborne pathogenic bacteria. M. candidum acetone extract had marked inhibitory effect on test bacteria introduced into sliced pork, which was then stored at 4 degrees C. At the end of storage (day 12), the bacterial concentrations dropped by 1.59 to 2.91 log CFU/g compared with the control. In steamed rice stored at 30 degrees C, a 0.2% extract decreased initial (before storage) concentrations of Bacillus cereus from 2.01 log CFU/g to an undetectable level, which remained for at least 24 h. After 72 to 168 h of storage, test bacterial concentrations were reduced by 2.59 to 5.66 log CFU/g. In fresh noodles stored at 30 degrees C, both initial and final bacterial concentrations were decreased. At the end of storage (72 to 168 h), test bacteria concentrations were reduced by 1.85 to 2.88 log CFU/g. Overall, M. candidum acetone extract had an inhibitory effect on foodborne pathogenic bacteria in different food model systems.     

苦瓜提取物对细菌的抑制作用初探

本文的研究对象为苦瓜提取物的抑菌活性并求出其抑菌比,通过对提取工艺进行优化,以及结合实验相关数据探讨了提取物的稳定性。实验结果表明,苦瓜提取物能够对部分细菌起到明显的抑制效果,金黄色葡萄球菌与枯草芽孢杆菌为其中最具代表性的细菌。大量提取单因素实验结果显示,若苦瓜粉末处于乙醇浓度为70%、料液比为1∶30,并保持60℃水浴回流4h后,得到的苦瓜提取物的抑菌效果最好。故得出结论,苦瓜提取物的稳定性较强,高温下处理的活性损失小,耐紫外线,抑菌活性时间长达一个月。     

粗壮女贞苦丁茶提取物对油脂氧化的抑制作用

目的 研究以乙醇作为溶剂的粗壮女贞苦丁茶提取物在油脂氧化过程中所发挥的抑制作用。方法 以花生油为模型,通过测定和比较其在贮藏过程中的过氧化值变化来评价提取物抑制油脂酸败的能力;通过体外化学分析的方法测定提取物的自由基清除能力、脂质过氧化抑制能力和还原能力来探究其抗氧化能力;最后通过测定其总酚和总黄酮含量以及高效液相色谱-质谱联用来分析鉴定提取物中的主要活性成分。结果[请增加适当的数据加以说明] 粗壮女贞苦丁茶提取物能有效减缓油脂过氧化值的升高,抑制油脂的氧化酸败;提取物展现出良好的自由基清除活性、脂质过氧化能力和还原能力;提取物中的总酚和总黄酮含量较高,分别达到了126.9 mg没食子酸当量/g提取物和135.6 mg槲皮素当量/g提取物;粗壮女贞苷B是提取物中的主要活性成分,经测定其含量为765.83 mg/g提取物,该物质也是提取物能在油脂中发挥抗氧化作用的重要原因。结论 粗壮女贞苦丁茶提取物能有效抑制油脂的氧化酸败,在油脂的加工和贮藏领域有潜在的应用价值。     

Effects of ice-nucleation active bacteria on the freezing of some model food systems

Cells of ice-nucleation active (INA) bacteria, Pseudomonas syringae and Erwinia herbicola , were cultured at 18°C with media of nutrient broth and/or yeast extract and harvested at late log phase for maximum ice nucleation activity. These cells were able to nucleate water to freeze at temperatures as high as −2°C. They were incorporated into model food systems, including sugar, protein solutions and oil/water suspensions, representing all major components of foods, to investigate their effects on freezing. The nucleation temperatures of all the treated models were significantly raised by between 3.0 and 5.9°C compared with controls when the freezer temperature was set at −6 to −7°C. The application of the INA cells also caused freezing of certain model solutions at −6°C, such as sucrose solution (10%), which did not freeze at the same conditions without INA bacterial cells. Additions of INA cells also shortened the total freezing time of the model systems by between 20 and 38%. These results suggest that with the application of bacterial ice nucleation, some current food freezing processes may be modified to operate at higher subzero temperatures to provide guaranteed freezing, energy savings and improvement of efficiency and product quality.     

Phytochemical bioaccessibility and in vitro antidiabetic effects of Chinese sumac (Rhus chinensis Mill.) fruits after a simulated digestion: insights into the mechanisms with molecular docking analysis

This work studied the effects of gastrointestinal digestion on the phytochemical bioaccessibility and in vitro anti-diabetic effects of different fractions from Chinese sumac fruits and delineated the underlying mechanisms by molecular docking. Results showed that gastric digestion significantly increased the phytochemical bioaccessibility and inhibitions for α-glucosidase, dipeptidyl peptidase-4 (DPP-IV) and advanced glycation end product (AGE) formation of the ethanol-extracted fraction, whereas intestinal digestion remarkably decreased these parameters (P < 0.05). For the free phenolic fraction, the parameters were remarkably reduced after gastric digestion but significantly increased after intestinal digestion (P < 0.05). Quercitrin and gvajaverin contributed the most to the α-glucosidase and DPP-IV inhibitions, and trigalloyl glucose and its isomer could be the primary bioactive substance responsible for AGE suppression. Quercitrin, the predominant phenolic compound, could effectively interact with crucial amino acid residues in α-glucosidase, DPP-IV and bovine serum albumin with hydrogen bonds and hydrophobic interactions to exert its inhibitions.