Effects of juice processing on cranberry antioxidant properties

The effects of the industrial juice process on the antioxidant capacities of cranberry samples and of three phenolic extracts (polar phenolics (E1), apolar phenolics (E2) and anthocyanins (E3)) adjusted at pH 2.5 and 7.0 were investigated. The free radical-scavenging (FRS) and the lipid peroxidation inhibition (LPI) activities of each sample and extract, were studied using a N,N-diethyl-p-phenylenediamine discoloration test and the thiobarbituric acid reactive substances assay, respectively. The FRS and the LPI results, expressed in mM Trolox® equivalent (TE)/mg phenol and mg TE/mL/mg phenol, respectively, showed a negative effect of the juice process steps on E1. The E2 and E3 extracts were also affected by the process but not as much. The milling step increased the FRS capacity of E2 and E3 extracts, but decreased their LPI capacity. The evaporation of the juice did not have a significant effect on the FRS capacity, but lowered the LPI capacity. Before and after each step of the juice process, the FRS capacity of the cranberry extracts was greater than the LPI capacity. The results were consistent in classifying the FRS capacity of the extracts in the following order of polarity: E1 > E3 > E2; and their total phenolic (TP) content in the following order: E3 > E2 > E1. In general, the neutralization of the pH of the extracts did not significantly influence the changes observed during the juice process in the FRS and LPI capacity, except for E3 for which a decrease in the LPI capacity was observed.     

Effect of juice processing on the cancer chemopreventive effect of cranberry

Cancer chemopreventive properties were evaluated in cranberries and cranberry products (mash, depectinized mash, pomace, raw juice, clarified juice and juice concentrate). Three extracts isolated from frozen cranberries and cranberry solids (mash, depectinized mash and pomace) containing anthocyanins, water-soluble and apolar phenolic compounds were tested. Cranberry juices and extracts were screened for their ability to induce the phase II xenobiotic detoxification enzyme quinone reductase (QR). The results showed that there was no cytotoxicity against the cells used in the test. All samples stimulated quinone reductase activity except the highest concentrations of the anthocyanin-rich extract of pomace, which inhibited QR activity. Also, the results showed that the QR induction for all samples varied with concentration and that there was an optimal concentration for which the QR induction was maximal. Although the three cranberry extracts were good QR inducers, our results indicated that the phenols present in aqueous extract showed QR inductions which were more important than those obtained with phenols present in solvent extracts. Also, the ability of phenols to stimulate the QR activity has been reduced continuously and significantly (P ≤ 0.05) during the technological process. Especially, it appears that conditions of the evaporation to obtain a juice concentrate exerted a significant effect (P ≤ 0.05) on inducer potencies of bioactive molecules.     

Antioxidant and antiradical properties of cranberry juice and extracts

The antioxidant capacities of cranberry juice and three extracts isolated from frozen cranberries containing anthocyanins, water-soluble and apolar phenolic compounds, were evaluated at pH 2.5 and 7, respectively. The free radical-scavenging (FRS) and the lipid peroxidation inhibition (LPI) activities of each samples, and extracts, were studied using the N,N-diethyl-p-phenylenediamine (DPD) decoloration test and the thiobarbituric acid reactive substances (TBARS) assay, respectively. The cranberry phenols displayed good free radical-scavenging properties, but were less efficient at inhibiting the peroxidation of lipids. Of all the samples tested, the water-soluble phenolic compounds showed the greatest free radical-scavenging (68.2 mmol TE/mg phenol) and antioxidant (13.4 mmol TE phenol) activities. The polarity of the phenols, the pH of the medium and the juice process had a great influence on the antioxidant activities. The phenols isolated from cranberries with an aqueous solvent have greater antioxidant properties than those extracted with an organic solvent mixture. The antioxidant activity of the cranberry samples adjusted at pH 2.5 was greater than those adjusted at pH 7. Compared to the cranberry extracts, the juice exhibited a much lower antioxidant activity, especially when compared with the extract containing water-soluble compounds which the extraction conditions were similar to those used to obtain the juice.     

Effect of different cranberry extracts and juices during cranberry juice processing on the antiproliferative activity against two colon cancer cell lines

The effect of cranberry extracts and juices during cranberry juice processing on the antiproliferative properties against colon cancer cells was investigated. Two colon cancer cell lines HT-29 and LS-513 were treated with different concentrations of cranberry phenolic extracts from fruits, puree, depectinised puree and pomace and different concentration of three juices (raw, filtered and concentrated juices). The phenolic extracts consisted of water-soluble phenolic compounds, apolar phenolic compounds and anthocyanins. These phenolic extracts and juices were tested against two cell lines at pH 2.5 (natural juice pH) and at pH 7.0 (physiological pH). All cranberry extracts and juices could inhibit the growth of both cell lines with the IC₅₀ values (the concentration of phenolic content required to inhibit 50% the growth of cancer cells) varied from 3.8 to 179.2 μg gallic acid equivalent/ml. It was found that three types of extracts from fruit at pH 7.0 were the most effective at inhibiting the growth of HT-29 cell line. Extracts containing anthocyanins from fruit and from pomace were the most and the least efficient, respectively, in inhibiting the growth of both cancer cell lines. Further, three juices at natural pH (pH 2.5) were more effective at inhibiting the growth of two cell lines as compared to juices at pH 7.0. Concentrated juice at both pH values was the most effective at growth inhibition of two cancer cell lines compared to two other juices.     

Impact of selected combinations of non-thermal processing technologies on the quality of an apple and cranberry juice blend

A blend of apple and cranberry juice was processed by a combination of a light-based technology (ultraviolet light (UV) (5.3 J/cm²) or high intensity light pulses (HILP) (3.3 J/cm²) in combination with pulsed electric fields (PEF) (34 kV/cm, 18 Hz, 93 μs) or manothermosonication (MTS) (5 bar, 43 °C, 750 W, 20 kHz). Selected physical and chemical attributes were evaluated pre- and post-processing, and the sensory attributes of non-thermally treated samples were compared to conventional pasteurisation (26 s, 72 °C). No significant changes were found in non-enzymatic browning, total phenolics and antioxidant activity of the juices. UV + PEF and HILP + PEF treatments did not affect the colour of the product and HILP + PEF processing retained more monomeric anthocyanins than any other combined treatment. Sensory analysis showed that UV + PEF and HILP + PEF combinations did not impact on odour and flavour of the juice, while combinations that included MTS adversely affected those attributes.     

连翘不同部位提取物抑菌效果的比较分析

本试验采用滤纸片扩散法测定了连翘的花、叶片、枝条、果实(分青翘和老翘)的乙醇提取物对三种细菌性病害大肠杆菌(Escherichia coli)、金黄色葡萄球菌(Staphylococcus aureus)、枯草芽孢杆菌(Bacillus subtilis)和3种真菌病害青霉菌(Penicillium)、葡萄灰霉菌(Botrytis cinerea)和黄曲霉(Aspergillus flavus)进行了抑菌效果的对比和分析。用液体悬浮培养法分别测定了连翘不同部位的乙醇提取物对3种细菌的最小抑菌浓度(MIC)。试验结果表明:连翘不同部位的乙醇提取物对供试细菌均表现出有较强的抑菌作用,其中果实中青翘提取物的抑菌作用最强、老翘和叶片的抑菌作用也比较强,且两者区别不大,枝条提取物的抑菌作用最弱;对3种供试真菌所有供试部位提取物的抑菌效果均比细菌差。不同部位的乙醇提取物对不同细菌的最小抑菌浓度(MIC)则表现较大差异。     

超高压加工对鲜榨胡萝卜汁品质的影响

重点研究了热敏性胡萝卜汁经200～600MPa超高压处理10min后其感官品质、理化性质及营养品质的变化情况。实验结果表明:经高压处理后胡萝卜汁色泽、可溶性固形物、总糖、α-和β-胡萝卜素含量与对照样相比差异不明显(P>0.05);总抗氧化能力在400MPa压力处理后降低较显著,600MPa处理有较显著的提高(P<0.05);此外,超高压处理后胡萝卜汁的pH降低,总酸含量增加,且样品的沉降稳定性提高,且变化都比较显著(P<0.05)。综合实验各方面的处理效果,600MPa处理后的胡萝卜汁品质最佳。因此,超高压能较好保持胡萝卜汁原有的品质和营养价值,可达到保持营养、提高品质和延长货架期的目的。     

Antimicrobial effects of selected plant essential oils on the growth of a Pseudomonas putida strain isolated from meat

The inhibitory effect of 60 different essential oils was evaluated on a Pseudomonas putida strain of meat origin, associated with meat spoilage. Essential oils were tested at concentrations from 0.003 to 0.8% (wt/vol) to determine minimum inhibitory and maximal tolerated concentrations (MIC and MTC, respectively) using an agar medium culture. Of the 60 samples tested, Corydothymus capitatus essential oil was the most active showing a MIC of 0.025% and a MTC of 0.06%. Seven essential oils (Cinnamomum cassia, Origanum compactum, Origanum heracleoticum, Satureja hortensis, Satureja montana, Thymus vulgaris carvacroliferum, Thymus vulgaris thymoliferum) have shown a strong antimicrobial activity against P. putida with a MIC of 0.05% and a MTC ranging from 0.013% to 0.025%. Ten other oils (Cinnamomum verum (leaf and bark), Eugenia caryophyllus, Cymbopogon martinii var. motia, Cymbopogon nardus, Melaleuca linariifolia, Origanum majorana, Pimenta dioica, Thymus satureoides, Thymus serpyllum) showed a high antimicrobial activity showing a MIC ranging from 0.1% to 0.4%, while the remaining were less active showing a MIC ? 0.8%.     

大蒜油抗菌作用的初步研究

就大蒜油对一些常见的污染食品的微生物进行了抑制与杀灭作用的研究。结果表明，大蒜油对供试微生物具有很强的抑制与杀灭作用。     

生姜澄清汁加工工艺研究

姜营养物质丰富,对人体健康极其有益。实验采用单宁、明胶、壳聚糖处理法对姜汁进行处理,通过测定姜汁的透光率及澄清后的姜汁热稳定性确定3种方法对姜汁澄清效果。结果表明:明胶添加量0.04‰,单宁添加量0.07‰,常温下静置1 h,此时姜汁的透光率可达到98.6%;壳聚糖添加量0.4‰,作用温度40℃,作用时间40 min,透光率为96.8%。经过壳聚糖-硅藻土结合法处理姜汁,透光率达99.2%。     

黄芪提取物抗菌作用及其方式的研究

研究了不同产地黄芪提取物对食品中常见的腐败菌和产毒菌的抗菌作用与方式。结果表明：黄芪醇提物比水提物的抗菌效果明显,来自内蒙古和甘肃黄芪提取物抗菌作用没有明显的差异,黄芪醇提取物的抗菌作用因菌种不同而有所不同。同时,黄芪提取物的抗菌作用方式为杀菌,且其抗菌作用与时间有关。     

复方植物提取物对嗜水气单胞菌的抑菌作用

采用琼脂扩散法和二倍稀释法测定了植物提取物的抑菌活性,用正交t值法对复合组方进行优化,并且采用HPLC法对组方进行有效成分分析.结果筛选出抑菌效果佳的植物提取物为茶多酚、五倍子、大黄、黄芩、诃子.筛选出优化方的药味组成为茶多酚、五倍子、大黄3种提取物,最佳剂量配比为质量比5:2:1.本组方对嗜水气单胞菌的最小抑菌浓度MIC达到78μg/mL.本组方有效成分质量分数为:表没食子儿茶素没食子酸酯(EGCG)12.6%;表儿茶素(EC)7.57%;表没食子儿茶素(EGC)4.26%;表儿茶素没食子酸酯(ECG)4.19%;儿茶素(1.03%);没食子酸1.18%.     

菠萝蜜果汁加工工艺的研究

以成熟的菠萝蜜果实为原料,采用单因素和正交试验,研究了澄清型菠萝蜜果汁的酶解工艺条件及调配方法。结果表明:用果胶酶酶解菠萝蜜果汁有明显的澄清效果,酶解菠萝蜜果汁的优化工艺条件为酶解温度50℃、酶解时间2.5h、果胶酶用量0.1%;酶解后的菠萝蜜果汁的最佳配方为糖度20°Bx、柠檬酸0.1%、抗坏血酸0.06%。     

蕺菜汁饮料生产工艺研究

对蕺菜汁饮料生产工艺作了研究。结果表明,以蕺菜地上茎或地下茎叶为原料,经１００℃烫漂１ｍｉｎ后破碎、榨汁,再用复合果胶酶澄清处理,最后经调配、精滤、灌装和灭菌等过程可制成风味独特的蕺菜汁饮料。添加少量的食盐有利于保持和改善蕺菜汁饮料的风味     

桑果汁饮料工艺技术的研究

对桑果汁饮料的工艺技术及影响因素进行了详细的试验和分析,提出了产品的较佳配方和工艺参数。     

加工和储藏条件对橙汁芳香成分的影响

橙汁的怡人香气是由多种挥发性化合物混合而成。鲜榨橙汁经热加工后性质更稳定,但对芳香物质影响较大。热处理会降低香气活性化合物含量,并产生异味物或其前体物。乙烯基愈创木酚、对伞花烃和香芹酮等异味物都是化学反应的产物,而丁二酮、愈创木酚和2,6-二氯苯酚则是微生物污染物。文中简述了橙汁的芳香物质组成,重点介绍了不同的加工方法、包装、储藏和微生物污染对橙汁芳香物质的影响的研究进展,并探讨了研究中存在的问题和未来的研究方向。     

Headspace fingerprinting as an untargeted approach to compare novel and traditional processing technologies: A case-study on orange juice pasteurisation

As a rule, previous studies have generally addressed the comparison of novel and traditional processing technologies by a targeted approach, in the sense that only the impact on specific quality attributes is investigated. By contrast, this work focused on an untargeted strategy, in order to take into account unexpected and unintended effects of (novel) processing, and to possibly uncover unknown compounds resulting from alternative processing. The potential of headspace GC–MS fingerprinting was explored as a tool to compare the impact of thermal, high pressure (HP) and pulsed electric field (PEF) processing for mild pasteurisation of orange juice. This study demonstrated that when processing conditions are selected based on equivalent microbial safety, the impact of heat, HP and PEF pasteurisation on the volatile profile of orange juice can be considered comparable. During refrigerated storage, however, indirect impact differences were revealed, which were attributed to differences in degree of enzyme inactivation.     

菠菜汁低温火腿肠加工工艺研究

以猪肉为主料，菠菜汁为配料，以玉米淀粉、大豆分离蛋白等为辅料，通过单因素试验和正交试验，针对菠菜汁低温火腿肠的配方进行了研究，结果表明：菠菜汁添加量为3％、肥瘦肉比例为7：3，淀粉添加量为10％、香辛料添加量1．5％，产品质量最好。     

加工工艺对石榴浓缩汁抗氧化能力的影响

研究加工工艺对石榴浓缩汁抗氧化能力的影响.通过对石榴浓缩汁加工工艺的模拟,分别采用分光光度法、DPPH法和FRAP法测定石榴汁在酶解、澄清、离心和杀菌等工艺过程中总多酚、总抗氧化能力及自由基清除能力的变化.结果表明:加工工艺显著影响浓缩石榴汁的抗氧化能力.石榴汁在加工过程中,总多酚水平、总抗氧化能力和自由基清除能力逐渐降低,影响较显著的工艺过程是酶解、澄清和杀菌.     

Effect of ozone processing on the colour,rheological properties and phenolic content of apple juice

Apple juice samples were ozonated with processing variables of ozone concentration (1–4.8% w/w) and processing time (0–10 min). Effects of processing variables on colour values (L, a and b), rheological properties and phenolic content were studied. Significant reductions in these parameters were observed during ozonation. Second order polynomial regression modelling was used to investigate the main effects of ozone concentration and processing time on the changes in the selected quality parameters of ozonated apple juice. Predicted models were found to be significant (p < 0.05) with low standard error and high coefficients of determination (R²).