紫外分光光度法同时测定饮料中山梨酸钾和苯甲酸钠

介绍了饮料中山梨酸钾和苯甲酸钠的紫外分光光度法同时测定方法。实验表明该方法可快速准确地测定饮料中的山梨酸钾和苯甲酸钠，样品中山梨酸钾最小检出限为0．00067g/L，回收率为92％-94％；苯甲酸钠最小检出限为0．0014g／L，回收率为94％-96％。     

豆制品中防腐剂苯甲酸钠、山梨酸钾的调查和分析

为了解市售豆制品中防腐剂使用状况,对宁波市内2家大型农贸市场和3家大型超市销售的豆制品中苯甲酸钠、山梨酸钾添加情况进行抽样调查。结果表明,52份样品中有21份不合格,占抽样总数的40.38%;单添加苯甲酸的样品为10个,占19.23%;单添加山梨酸的样品为8个,占15.38%;同时添加苯甲酸和山梨酸的样品为3个,占5.78%。此调查结果可以为食品卫生监督部门加强豆制品生产、加工以及流通各个环节的监管提供参考依据,从而保障消费者的身体健康。     

苯甲酸钠和山梨酸钾的复配抑菌效果研究

采用液体培养法和比浊法研究苯甲酸钠和山梨酸钾的3种复合配伍(1∶1∶2∶3∶3∶2)对大肠杆菌和金黄色葡萄球菌的抑菌效果,运用SPSS16.0统计软件对所测数据进行统计分析,从中筛选最佳抑菌配伍及最佳抑菌浓度.结果表明,这两种防腐剂的3种复合配伍对两种菌的生长都有显著的抑制作用,且随质量浓度增加抑菌作用逐渐增强.苯甲酸钠和山梨酸钾复合配比为3∶2时,对大肠杆菌的抑菌效果较好;复合配比为2∶3时,对金黄色葡萄球菌的抑菌效果较好;3种复合配伍的最佳抑菌浓度均为1.0 g/L.     

Sodium benzoate and potassium sorbate preservatives in Iranian doogh

Sodium benzoate and potassium sorbate are two common preservatives used in Iran, yet use of these preservatives in doogh (Iranian dairy-based drink) is forbidden according to national standards. The aim of this study was to consider the presence of these preservatives in doogh by high-performance liquid chromatography with UV detection (HPLC–UV). The method was performed using a C₁₈ column and detection at 225 nm. The mobile phase contained ammonium acetate buffer (pH = 4.2) and acetonitrile (80:20 v/v). The survey included 130 samples of doogh for identification and quantification of the named preservatives. All samples contained sodium benzoate, but potassium sorbate was detected in only 13% of them. The means of benzoate and sorbate were 21.3 ± 2.7 and 13.3 ± 39.6 mg kg^?1, respectively. The limits of detection were 2 and 40 ng g^?1 for benzoate and sorbate, respectively. Results indicate that sodium benzoate may occur in doogh naturally.     

Sodium benzoate and potassium sorbate preservatives in food stuffs in Iran

A high-performance liquid chromatography method was applied for the determination of the levels of benzoate and sorbate in 400 food samples, including pickled cucumbers, canned tomato pastes, sour cherry jams, soft drinks, fruit juices and dairy products (UF-Feta cheeses, Lighvan cheeses, lactic cheeses, yogurts and doogh). The results showed that 270 (67.5%) of all samples contained benzoate ranging from 11.9 to 288.5 mg kg^?1 in lactic cheese and fruit juice, respectively. The levels of sorbate in 98 (24.5%) of the samples were 20.1 to 284.3 mg kg^?1 in doogh and fruit juice, respectively. Moreover, benzoate was detected in all dairy products ranging from 11.9 mg kg^?1 in lactic cheese to 91.2 mg kg^?1 in UF-Feta cheese. A low concentration of benzoate could originate naturally, due to specific biochemical mechanisms during cheese, yogurt and doogh maturation. In conclusion, a minimum level for benzoate in dairy products should be defined in the legislation.     

Effect of brine replacement and salt concentration on the fermentation of naturally black olives

This study was undertaken to modify the traditional fermentation of naturally black olives in order to obtain higher quality black table olives. After holding olives in tap water or low salt brine prior to fermentation, acidification of the cover brine and fermentation at two different salt concentrations (6 and 14 g/ 100 ml NaCl) were applied to Gemlik variety olives in three batches. Fermentations were monitored using physical, chemical and microbiological analyses and effects of the above changes to fermentation were investigated. Yeasts were the predominant microorganisms in all of the batches. Growth enhancement of lactic acid bacteria by brine replacement occurred in the fermentation with 6 g/ 100 ml NaCl cover brine but not with 14 g/100 ml NaCl brine. The highest level of titratable acidity (0.59 g/100 ml) formed during fermentation with 6 g/100 ml NaCl brine followed by fermentation with 6 g/100 ml NaCl brine (0.43 g/100 ml) where the brine was replaced after 48 days. The lowest level of titratable acidity (0.36 g/100 ml) was formed using a high salt brine. Reducing sugars were consumed effectively by microorganisms in all the batches and residual levels in the brines were 0.05–0.1 g/100 g ml. NaCl contents of the final products were 5.20 g/ 100 g (olives with high salt brine) and 3.27–3.58 g/100 g (olives with low salt brine). Moisture contents of the processed olives were in the range 49.58–50.79 g/ 100 g. The water activity (a_w) value of olives fermented with the high salt brine was found to be 0.947 while a_w values of olives fermented with the low salt brine were 0.962–0.964. Protein content of the olives ranged between 1.76–1.95 g/100 g and the ash contents were found to be 2.41–2.81 g/100 g in olives with low salt brine and 4.70 g/100 g in olives with high salt brine. According to sensory evaluations of the final products, no differences between the treatments were found (P > 0.05).     

不同贮藏温度下山梨酸钾和焦亚硫酸钠对南酸枣皮浆品质的影响

在不同贮藏温度（4,25,35 ℃）下,研究山梨酸钾或焦亚硫酸钠对南酸枣皮浆菌落总数、L^*值、多酚含量、DPPH自由基清除力和pH的影响。结果表明：0.050%山梨酸钾或0.015%~0.050%焦亚硫酸钠均可有效抑制南酸枣皮浆微生物生长;0.015%焦亚硫酸钠在南酸枣皮打浆过程和贮藏前期具有较好的护色效果,但随贮藏时间的延长,其护色效果与0.050%山梨酸钾的无显著差异（P>0.05）,且二者对南酸枣皮打浆和贮藏过程中多酚含量和DPPH自由基清除率的影响无显著差别（P＞0.05）;低温（4 ℃）有利于南酸枣皮浆贮藏;在贮藏过程中L^*值和多酚含量变化分别符合一级和零级降解动力学模型。     

Induced lactic acid fermentation of untreated green olives of the Conservolea cultivar by Lactobacillus pentosus

Inoculation of untreated green olives of the Conservolea cultivar (Olea europea media rotunda) with a commercial strain of Lactobacillus pentosus with/without glucose supplement was studied. Despite an initial loss in viability of 0.5 log cycles on average, due to lack of adaptation of the starter to the saline environment of the brine, cultures grew well and initiated an accelerated fermentation process. Inoculation reduced the survival period of Enterobacteriaceae, and consequently potential spoilage, and caused a quicker acidification of brines and decrease in pH compared with control uninoculated processes. The diffusion of phenolic compounds was slow, hindered by the epidermis of the fruits, and had no effect on the growth of the starter. HPLC analysis revealed that lactic and acetic acids were among the end‐products during the fermentation of green olives. Citric, tartaric and malic acids were also detected but at much lower concentrations. Results obtained from this work can be applied directly to industry for the effective use of starter cultures on natural fermentation processes of green olives without prior lye treatment. © 2003 Society of Chemical Industry     

Sodium benzoate,potassium sorbate and sodium nitrite as silage additives

BACKGROUND: The hygienic quality of silage is important for animal health, animal production and food quality. The aim of this study was to evaluate the effect of five silage additive mixtures on yeast, mould, and clostridia growth and other silage quality criteria. The additives, composed of sodium nitrite, sodium benzoate and/or potassium sorbate, were used to treat a grass forage crop before ensiling. The silages were compared with untreated silage and silages treated with two commercial additives: Promyr NF (PNF), which is based on formic and propionic acid, and Kofasil Ultra (KU), a mixture of sodium nitrite, sodium benzoate, sodium propionate and hexamine. RESULTS: All tested additives significantly (P < 0.001) reduced butyric acid and ammonia‐N formation in low‐dry‐matter (DM) silages compared to the control. Only KU and the mixtures of 600 g sodium nitrite, 250 g sodium propionate, 750 g sodium benzoate (A1) and 250 g sodium nitrite with 1000 g sodium benzoate and 500 g potassium sorbate (A5) ton^?1 of fresh forage were found to reduce (P < 0.001) the presence of clostridia spores in low‐DM silages. In high‐DM silages, treatments A1, A5 and A2 (250 g sodium nitrite and 1000 g sodium benzoate) contained less (P < 0.02) yeast than the control and PNF, but not KU. All treated silages were aerobically stable. The concentrations of nitrate‐N in all silages and nitrite‐N in low‐DM were below the threshold level for feed at the end of storage. CONCLUSIONS: The additive mixtures A1 and particularly A5 improved silage quality at least to the same extent as commercial products, even though they contained no hexamine and less nitrite. Copyright © 2009 Society of Chemical Industry     

壳聚糖抗菌膜中山梨酸钾迁移的数学模型及实验分析

运用Fick第二定律对壳聚糖抗菌膜中山梨酸钾的迁移过程进行预测,建立其数学模型。结果表明,当山梨酸钾初始浓度相同,壳聚糖浓度升高时,扩散系数D减小;当壳聚糖浓度不变时,山梨酸钾浓度升高扩散系数D变大。通过幂律模型Mt/M∞=k×tn可确定实验中的山梨酸钾在壳聚糖抗菌膜中迁移机制的类型为菲克扩散。     

山梨酸钾对魔芋葡甘聚糖/玉米醇溶蛋白复合膜的性能和抑菌效果的影响

本文以魔芋葡甘聚糖和玉米醇溶蛋白为基材,制备了不同山梨酸钾添加量的复合膜,研究了复合膜的理化性能和抑菌效果。结果表明,添加不同含量山梨酸钾对复合膜的膜厚没有显著影响(p>0.05),复合膜的水蒸气透过率和透光性随着山梨酸钾添加量的增加而降低。复合膜的断裂伸长率随着山梨酸钾添加量的增加而显著增大(p<0.05),当其含量为12%时,复合膜的断裂伸长率为36.02%,是未添加山梨酸钾复合膜的1倍;当添加6%的山梨酸钾时,复合膜的拉伸强度最大,为58.78 MPa。随着山梨酸钾添加量的增加,复合膜对大肠杆菌、金黄色葡萄球菌和蜡样芽孢杆菌的抑菌效果明显增强。当山梨酸钾添加量为12%时,鱼肉在4℃储藏时的货架期可延长4 d。复合膜适合应用在食品保鲜包装。      

江西省居民膳食中山梨酸及其钾盐暴露风险评估

目的评估江西省居民膳食中山梨酸及其钾盐的暴露水平和潜在健康风险。方法利用2012—2016年江西省食品中山梨酸及其钾盐含量数据、2016年江西省居民食物消费量调查数据,采用简单分布评估法计算江西省居民膳食中山梨酸及其钾盐的暴露水平,并进行健康风险评估。结果江西省居民膳食中山梨酸及其钾盐每日平均暴露量及每日高暴露量(P95)分别为0.031和0.085 mg/kg BW,分别占暂定组每日允许摄入量(ADI,3 mg/kg BW)的1.03%和2.83%。西式糕点、大米制品、熟肉制品是江西省居民膳食中山梨酸及其钾盐暴露的主要来源,贡献率达到总膳食暴露量的75%以上。如果严格执行GB 2760—2014《食品安全国家标准食品添加剂使用标准》中关于山梨酸及其钾盐限量规定,江西省居民膳食中山梨酸及其钾盐每日平均暴露量和每日高暴露量分别下降25.7%～49.5%和14.5%～27.9%,西式糕点、果蔬汁类饮料、新型豆制品则成为膳食中山梨酸及其钾盐暴露的主要来源。结论目前江西省居民膳食中山梨酸及其钾盐暴露量对人群健康造成的风险较低,处于可接受水平,但仍有部分暴露来源于食品添加剂滥用,需要关注。     

The ensiling capability of a mixture of sodium benzoate, potassium sorbate, and sodium nitrite

The objective of this study was to evaluate the effects of an additive comprising sodium benzoate, potassium sorbate, and sodium nitrite on the quality of silages fermented from various forage crops. Thirteen crops in 3 groups (differing in dry matter concentration and degree of ensilability) were treated with the additive mixture and compared with untreated control silages. The main focus was on yeast and Clostridia spp. activity in the silages, although other silage quality criteria also were measured. Treated silages from difficult-to-ensile crops at low dry matter were found to have significantly lower silage pH, fewer clostridial spores, and reduced concentrations of ammonia N, butyric acid, and ethanol. In addition, dry matter losses were reduced in treated silages compared with those receiving no additive. Similar results were observed in silages from easy or intermediate ensilable crops when the dry matter concentration was <300 g/kg. When the dry matter concentration was >350 g/kg, the treated silages contained less ammonia N, ethanol, and yeast for 3 out of 4 forages. All treated silages from all crops were aerobically stable during the examination time. The application of the tested additive mixture reduced the growth of undesirable microflora and thereby reduced silage losses and prolonged the aerobic stability of the silages.     

苯甲酸和苯甲酸钠安全性与检测方法研究进展

苯甲酸和苯甲酸钠是一种酸性防腐剂,过量滥用很危险;因苯甲酸和苯甲酸钠被人体过量摄入后,会对人体健康造成极大危害,甚至致癌。该文对苯甲酸和苯甲酸钠残留安全性及检测方法进行综述,以期为苯甲酸和苯甲酸钠残留检测方法研究提供参考。     

海藻酸钠-羧甲基纤维素-山梨酸钾复合抗菌膜的制备

以海藻酸钠为成膜基料,羧甲基纤维素钠为共混膜的原料,并添加了增塑剂甘油和防腐剂山梨酸钾,通过测定膜的透明度、厚度、力学性质等指标,确定复合抗菌膜成膜液的最佳组成为:1.5%海藻酸钠,1.5%羧甲基纤维素钠,1%甘油,3%山梨酸钾,成膜材料海藻酸钠∶羧甲基纤维素钠=85∶15。      

壳聚糖及其金属锌配位络合物的抑菌性能研究

本研究在合成一种壳聚糖锌配合物后,测试了合成的壳聚糖锌、合成原材料壳聚糖的抑菌效果,以及不同pH条件对抑菌效果的影响,并比较了壳聚糖锌和常见的食品防腐剂苯甲酸钠、山梨酸钾对大肠杆菌ATCC8099、金黄色葡萄球菌ATCC6538、枯草杆菌黑色变种ATCC9372、白色念珠菌ATCC10231和黑曲霉ATCC16404的最低抑菌浓度。结果表明:合成的壳聚糖锌与合成前的壳聚糖相比抑菌性能大大提高;合成后的壳聚糖锌对细菌的抑菌效果与常见的食品防腐剂苯甲酸钠、山梨酸钾相当,但对真菌的抑制时效没有苯甲酸钠、山梨酸钾好。同时系统的pH对壳聚糖锌和壳聚糖都有较大的影响,酸性条件下抑菌效果较好。     

Effect of calcium chloride on mechanical properties and microbiological characteristics of cv. Conservolea naturally black olives fermented at different sodium chloride levels

The effect of calcium chloride (CaCl₂)(5 gL^?1) and sodium chloride (NaCl) concentration (40, 60 and 8 gL^?1) on the microbiological and mechanical properties of naturally black olives of cv. Conservolea in brines was studied. In 40 and 60 g L^?1 brines the growth of lactic acid bacteria was favoured over that of yeasts, resulting in rather complete lactic acid fermentation as indicated by high free acidity (9.8–11.5 g lactic acid L^?1) and low pH (3.7–3.8). At 80 g L^?1 brine, yeasts were the dominant members of the microflora, rendering a product with lower acidity (8 g lactic acid L^?1) and higher pH (4.3–4.5). In the presence of CaCl₂ there was a consistent increase in the depth of the peripheral region in which cell wall breakage occurred. When cells separated, perforated walls were observed at sites associated with plasmodesmata. The flesh was strongest and stiffest when CaCl₂ was added to olives treated with 40 g L^?1 brine, consistent with cell wall breakage being the predominant mode of failure. The only observed effect on the mechanical properties of the skin was a stiffening at 60 g L^?1 brine on addition of CaCl₂. Copyright © 2007 Society of Chemical Industry     

A study on the implications of NaCl reduction in the fermentation profile of Conservolea natural black olives

This study examined the impact of different mixtures of NaCl, KCl, and CaCl₂ on the fermentation profiles of Conservolea natural black olives. Five different combinations of chloride salts were investigated, namely (i) 8% NaCl (control treatment), (ii) 4% NaCl and 4% KCl, (iii) 4% NaCl and 4% CaCl₂, (iv) 4% KCl and 4% CaCl₂, and (v) 2.6% NaCl-2.6% KCl-2.6% CaCl₂. The changes in the microbial association (lactic acid bacteria, yeasts, Enterobacteriaceae), pH, titratable acidity, organic acids, volatile compounds, and mineral content in olive flesh were analyzed. Results demonstrated that all salt combinations led to vigorous lactic acid processes based on the obtained values of pH (3.9-4.2) and titratable acidity (0.70-0.86 g lactic acid per 100 ml brine). Organoleptic evaluation was a critical factor in the acceptability of the final product. Increasing concentrations of CaCl₂ or a combination of KCl and CaCl₂ rendered the product bitter with low acceptability by the taste panel. Only one combination of chloride salts (4% NaCl and 4% KCl) could finally produce olives with lower sodium content and good organoleptic attributes. The results of this study could be employed by the Greek table olive industry in an attempt to produce natural black olives with less sodium without affecting the traditional taste of fermented olives in order to meet consumers’ demand for low sodium dietary intake.     

Main variables affecting the lactic acid fermentation of table olives

Among the olive varieties, Manzanilla is the most employed as table olives worldwide. Inoculation of the brines of Manzanilla and Gordal olives, which were not treated with alkali, with a strain of Lactobacillus pentosus was carried out and results indicated that variety is one of the main factors to be considered when fermenting olives, even more important than the salt level. This conclusion was based on the presence of a high concentration of antimicrobial compounds, namely the dialdehydic form of decarboxymethyl elenolic acid, either free or linked to hydroxytyrosol in the brines of the Manzanilla variety, as compared to the low level of these substances in the Gordal brines. Likewise, it was also observed that the inhibitory activity of Manzanilla olives against lactic acid bacteria could be counteracted by the addition of nitrogenous supplements such as MRS and yeast extract to their brines. Results obtained from this work are of great interest for the table olive industry in order to develop lactic acid fermentation in olives non‐treated with alkali.