Sensory properties of kishk: comparison of products containing bovine and caprine milk

There is growing consumer interest in fermented milk and in products containing fermented milk because of their nutritional value and healthy image. Kishk, a traditional product of Middle Eastern origin, has been examined with a view to developing its potential for a wider market. Kishk is traditionally made from a dough, containing yogurt, parboiled cracked wheat and salt, which is sun dried then ground to a flour. The flour may be consumed in a variety of ways, but one popular use is in the preparation of a hot, porridge like gruel. This paper describes the sensory profiles of gruel made from 15 samples of kishk and compares them with those of two traditional Scottish oatmeal porridges. Substantial differences were noted between kishk and the oat based products. In addition, there was evidence that the origin of the fermented milk component of the kishk was important. Kishk made from fermented caprine milk was clearly distinguished from that made with yogurt of bovine origin. It was noted that many of the kishk samples were rated highly for bitterness and for cardboard character. Such attributes are believed to be disliked by consumers in the United Kingdom .     

Decontamination of fluid milk containing Bacillus spores using commercial household products

Although commercial sanitizers can inactivate bacterial spores in food processing environments, relatively little data exist as to the decontamination of products and surfaces by consumers using commercial household products. Should a large scale bioterrorism incident occur in which consumer food products were contaminated with a pathogenic sporeformer such as Bacillus anthracis, there may be a need to decontaminate these products before disposal as liquid or solid waste. Studies were conducted to test the efficacy of commercial household products for inactivating spores of Bacillus cereus (used as a surrogate for B. anthracis) in vitro and in fluid milk. Validation of the resistance of the B. cereus spores was confirmed with B. anthracis spores. Fifteen commercial products, designed as either disinfectants or sanitizers or as potential sanitizers, were purchased from retail markets. Products selected had one of the following active compounds: NaOCl, HCl, H2O2, acetic acid, quaternary ammonium compounds, ammonium hydroxide, citric acid, isopropanol, NaOH, or pine oil. Compounds were diluted in water (in vitro) or in 2% fat fluid milk, and spores were exposed for up to 6 h. Products containing hypochlorite were most effective against B. cereus spores. Products containing HCl or H2O2 also reduced significant numbers of spores but at a slower rate. The resistance of spores of surrogate B. cereus strains to chlorine-containing compounds was similar to that of B. anthracis spores. Therefore, several household products on the market may be used to decontaminate fluid milk or similar food products contaminated by spores of B. anthracis.     

水产品中二氧化硫残留量的调查分析

目的了解我国市售水产品中二氧化硫(sulfur dioxide,SO_2)的残留状况,为制定和完善水产品中SO_2限量标准提供科学依据。方法根据GB/T5009.34-2016《食品安全国家标准食品中二氧化硫的测定》中的检测方法,对山东、浙江、天津2014~2016年市售的虾蟹类及其制品101例、鱼类及其制品95例、贝类及其制品42例和头足类及其制品29例共267例样品进行SO_2残留检测。结果水产品及其制品中SO_2的残留量范围为ND~3994.38 mg/kg,平均残留量达到57.10 mg/kg,多数处于较低水平。不同种类的水产品及其制品中SO_2的残留量差异有统计学意义(P0.05),其中虾蟹类及其制品中的SO_2的残留量明显高于其他水产品,其残留量平均值达到130.93 mg/kg,其中最大值为3994.38 mg/kg。结论 SO_2在不同种类的水产品中均有不同程度的存在,水产品中SO_2残留问题亟需关注。     

Determination of levamisole in livestock products using high performance liquid chromatography

A method is described for the determination of the anthelmintic levamisole in muscle, liver, kidney and fat of cattle, swine and poultry using high performance liquid chromatography with photodiode array detection. Levamisole was extracted from an alkaline sample with ethyl acetate and back-extracted with 0.1 mol/L hydrochloric acid. The extract was applied to an SCX solid-phase extraction column. The column was washed with water and methanol. Levamisole was eluted with a solution of ammonia in methanol. The eluate was evaporated to dryness and the residue was dissolved in the mobile phase and injected into the HPLC system. Mean recoveries from 0.01-0.10 microgram/g fortified muscle, liver, kidney and fat samples ranged from 78.3 to 99.8%. The detection limit for the assay was 0.005 microgram/g.     

Study of food products containing gluten by using the method of polymerase chain reaction

The results of studies on the detection of gluten in the 7 products, members of the group of gluten-free, used for patients with celiac disease. Used the method of polymerase chain reaction detection in real time (by method of polymerase chain reaction) using a test system SureFood Allergen Gluten. With this method, fully meets the requirements of the Codex Alimentarius Commission, confirmed the compliance of the investigated food gluten-free category, used for patients with celiac disease.     

Production and quality improvement of Indian cottage cheese (Paneer) using high pressure processing

Paneer, a product of India similar to cottage cheese, was prepared from cow's milk heat-treated (90 °C/5 min) (HTMP) or high-pressure (HP) treated (500 MPa/15 min) (HPPMP) for achieving pasteurization. HTMP and HPPMP paneer samples were HP treated (500 MPa for 15 min) again after vacuum packaging to get HTMP/HPP and HPPMP/HPP samples, respectively. The third set of samples were obtained by dipping HTMP and HPPMP paneer samples in 2% lactic acid solution and then subjecting them to the same HP treatment and stamped as HTMP/LA/HPP and HPPMP/LA/HPP, respectively. All six types of vacuum-packed paneer were studied for changes in moisture, acidity, pH, color, texture, and microbiological quality during storage at 5 ± 1 °C and 25 ± 1 °C. High-pressure treatment of milk increased the yield of paneer significantly (P < 0.05) from 13.9 ± 0.59% (HTMP) to 18.2 ± 0.32% (HPPMP). Paneer treated with lactic acid and high-pressure treatment (HTMP/LA/HPP and HPPMP/LA/HPP) had higher textural stability than HTMP, HTMP/HPP, HPPMP, and HPPMP/HPP for up to 28 days, but had a reduced moisture content, higher acidity, and lower whiteness index. High-pressure treatment of vacuum-packed paneer (HTMP/HPP and HPPMP/HPP) led to the formation of a more compact paneer matrix (higher hardness), higher moisture expulsion, and yellowness (b*). Thus, high-pressure processing of paneer could pave paths for extending paneer shelf-life without any additives and thermal treatment.     

高效液相色谱法测定金枪鱼产品中的生物胺含量

目的 建立高效液相色谱法检测金枪鱼产品中8种常见生物胺的含量。方法 样品经酸介质提取, 丹磺酰氯衍生, 0.22 μm有机膜过滤后, 采用CAPCELL Pak C18 MGⅡ色谱柱(150 mm×4.6 mm, 5 μm), 以甲醇-超纯水为流动相进行梯度洗脱, 流速0.8 mL/min, 柱温为室温。生物胺各组分以外标法进行定量。结果 采用0.4 mol/L高氯酸提取样品3次, 可以获得最优的生物胺提取效果。生物胺各组分浓度为0.17~2.25 mg/kg范围呈良好的线性关系(r>0.999), 平均加标回收率为86.6%~115.9%, 相对标准偏差为1.5%~13.7%。?80 ℃金枪鱼刺身的总生物胺含量低于10 mg/kg, 冰鲜金枪鱼刺身的总生物胺含量要高于?80 ℃金枪鱼刺身, 但低于 100 mg/kg; 金枪鱼罐头主要含有组胺、尸胺、腐胺和酪胺, 总生物胺含量范围为106.63~357.09 mg/kg; 金枪鱼松的总生物胺含量范围为111.20~751.54 mg/kg; 部分金枪鱼罐头和金枪鱼松的组胺含量超过50 mg/kg。 结论 建立的高效液相色谱法可以准确测定金枪鱼产品中的8种常见生物胺含量, 本文测定的金枪鱼刺身产品中生物胺含量较低, 不存在安全隐患, 部分金枪鱼罐头和金枪鱼松的生物胺(尤其是组胺)含量较高, 有出口退回风险, 应引起足够重视。     

大豆蛋白特性对其高湿挤压纤维化产品的影响

研究大豆蛋白的特性对其高湿挤压纤维化的影响,分别选用低温脱脂豆粉、大豆分离蛋白和五个不同品种的大豆为原料进行实验。研究了氮溶解指数(NSI值)、粒度及大豆蛋白7S/11S比值等因素对高湿挤压纤维化产品特性的影响。实验结果表明,挤压原料特性对高湿挤压纤维化产品的感官质量、质构特性及微观结构产生较明显的影响。较高NSI值和较低粒径范围(0.076～0.135mm)原料的挤压产品纤维化结构较好;大豆11S球蛋白在挤压加工过程中起重要作用,提高11S球蛋白的含量,在一定程度上可以提高挤压纤维化产品的品质。      

Production of novel dairy products using actinidin and high pressure as enzyme activity regulator

Milk clotting for the production of novel dairy products, alternative or complementary to cheese and yogurt type products can be achieved using plant sulfhydryl proteases. The objective was to apply the protease actinidin, from Actinidia chinensis, as the milk clotting agent, and High pressure (HP) technology to control excessive proteolysis. The effect of the dairy substrate and the process parameters on the coagulation rate and the texture and sensory properties of the end product, were studied. Selected values of design parameters were 25% total solids, 6.49 adjusted pH, 0.35 U activity of the clotting agent actinidin, 40 ºC process temperature and 2 h time. The selected pressure-temperature conditions, 600 MPa at 40 ºC, were applied to stop the potentially detrimental further proteolytic action of the enzyme. Results indicated that use of actinidin for milk clotting and HP to stop the enzyme activity in the final product, leads to a “fresh cheese” type dairy product.Industrial relevance: Alternative clotting methods for novel dairy products, complementary to cheese and yogurt type products, are of interest to the industry. Plant proteases can be a viable approach, provided that excessive proteolysis after structure formation is regulated. High hydrostatic pressure can be used for controlling proteolytic activity in the final products without affecting their texture and sensory characteristics.     

Using high pressure microfluidization to improve physical properties and lycopene content of ketchup type products

This study evaluates the effects of high pressure microfluidization of ketchup mixes on the physical properties and lycopene content. During the processing the pressure level ranged between 200 and 2000 bar, while the number of passes was kept constant. When the treatment pressure was increased from 200 to 1200 bar, the yield stress, elastic modulus, storage modulus, and Bostwick consistency values of the ketchup samples improved. However, over-processing was observed for the samples treated at 1600 and 2000 bar. Light and scanning electron microscope images were used as visual means to observe microfluidization induced structural changes. Colloidal stability measurement showed that increasing microfluidization pressure improved physical stability of the samples. Reducing the size and changing the nature of tomato solids through high pressure microfluidization also increased the detectable lycopene levels of the ketchup samples.     

Radiolysis products and sensory properties of electron-beam-irradiated high-barrier food-packaging films containing a buried layer of recycled low-density polyethylene

The aim was to study the effect of electron-beam irradiation on the production of radiolysis products and sensory changes in experimental high-barrier packaging films composed of polyamide (PA), ethylene-vinyl alcohol (EVOH) and low-density polyethylene (LDPE). Films contained a middle buried layer of recycled LDPE, while films containing 100% virgin LDPE as the middle buried layer were taken as controls. Irradiation doses ranged between zero and 60 kGy. Generally, a large number of radiolysis products were produced during electron-beam irradiation, even at the lower absorbed doses of 5 and 10 kGy (approved doses for food ‘cold pasteurization’). The quantity of radiolysis products increased with irradiation dose. There were no significant differences in radiolysis products identified between samples containing a recycled layer of LDPE and those containing virgin LDPE (all absorbed doses), indicating the ‘functional barrier’ properties of external virgin polymer layers. Sensory properties (mainly taste) of potable water were affected after contact with irradiated as low as 5 kGy packaging films. This effect increased with increasing irradiation dose.     

加工水果中二氧化硫测定方法研究比较

目的根据加工水果的特点,比较及建立一种适合实验室简便快速测定其二氧化硫残留量的方法。方法分别用蒸馏滴定法与离子色谱法对样品中的二氧化硫残留量进行测定和比较。结果全自动蛋白测定仪结合离子色谱仪法测定加工水果中的二氧化硫残留量的准确度、精密度、检出限均优于蒸馏滴定法。结论建立的方法简便省时,结果准确可靠,污染少,适合大批量的加工水果中二氧化硫残留量的测定。     

焙烤食品原料及成品中二氧化硫残留含量的调查分析

此调查旨在了解焙烤食品原料及其成品中二氧化硫残留含量的水平,为食品风险监测提供参考数据;该实验依据GB/T5009.34-2003食品中亚硫酸盐(蒸馏法)分析方法对采集来的84份样品进行检测,其中面粉14份,食品馅料18份,食糖20份,焙烤食品32份。结果表明:面粉、食品馅料、食糖、焙烤食品二氧化硫平均检出值分别为0.0043 g/kg、0.0037 g/kg、0.012 g/kg和0.0061 g/kg,均属于低残留水平。说明目前市场上售卖的焙烤食品原料和成品中二氧化硫的残留量水平较低,不足以对人体健康构成安全风险。     

Tailoring structure and technological properties of plant proteins using high hydrostatic pressure

The demand for proteins is rising and alternatives to meat proteins are necessary since animal husbandry is expensive and intensive to the environment. Plant proteins appear as an alternative; however, their techno-functional properties need improvement. High-pressure processing (HPP) is a non-thermal technology that has several applications including the modification of proteins. The application of pressure allows modifying proteins' structure hence allowing to change several of their properties, such as hydration, hydrophobicity, and hydrophilicity. These properties may influence the solubility of proteins and their ability to stabilize emulsions or foams, create aggregates or gels, and their general role in stability and texture of food commodities. Commonly HPP decreases the proteins' solubility yet increasing their surface hydrophobicity exposing sulfhydryl groups, which promotes aggregation or gelation or enhance their ability to stabilize emulsions/foams. However, these effects are not verifiable for all the proteins and are immensely dependent on the type and concentration of the protein, environmental conditions (pH, ionic strength, and co-solutes), and HPP conditions. This review collects and critically discusses the available information on how HPP affects the structure of plant proteins and how their techno-functional properties can be tailored using this approach.     

Rapid determination of formaldehyde and sulfur dioxide in food products and Chinese herbals

Simple, sensitive and rapid methods for the determination of formaldehyde and sulfur dioxide were developed. The formaldehyde determination is based on the reaction between formaldehyde and acetylacetone solution, producing yellow 3,5-diacetyl-l-1,4-dihydrolutidine. Sulfur dioxide was detected as the deoxidize of sulfurous acid by zinc in acidic medium, which produces sulfureted hydrogen that make lead acetate paper blackening due to lead sulfide formation. The detection limits were 0.8 μg mL⁻¹ and 6.0 μg mL⁻¹ for formaldehyde and sulfur dioxide, respectively. The linear range were 0.8–20.0 μg mL⁻¹ for formaldehyde and 6.0–100.0 μg mL⁻¹ for sulfur dioxide determination. The main advantages of the new analytical procedure are the low background level, high selectivity, and very little sample preparation for on-site analysis of formaldehyde and sulfur dioxide in food or Chinese herbal samples with reference color card for qualitative or semi-quantitative determination. The results from these methods correlated well with those obtained from the standard methods.     

面制品及糕点中含铝食品添加剂的测定

以乙二胺四乙酸二钠溶液为提取剂,选择性提取面制品及糕点中含铝食品添加剂残留铝,提取液酸化后用ICP-MS测定,实现了面制品及糕点中添加剂残留铝的准确测定。考察了超纯水、氢氧化钾溶液、硝酸溶液(2%)、EDTA二钠溶液及草酸溶液对食品中添加剂残留铝的提取效果和选择性,研究了EDTA二钠提取剂浓度、提取时间、提取温度及振摇时间间隔对添加剂残留铝提取效率的影响。结果表明,最佳提取条件为EDTA二钠提取剂浓度300μg/mL、提取时间30min、提取温度90℃、振摇时间间隔10min。对海苔麻花及蛋糕分别进行50mg/kg、100mg/kg两种梯度加标,加标回收率为98.0%~100.5%,相对标准偏差为1.36%~2.58%,方法检出限为0.026mg/kg,定量限为0.087mg/kg。     

Quantification of glycolic acid in cosmetic products using reversed phase high performance liquid chromatography

Many cosmetics contain keratolytic hydroxy acids to correct the effects of photoageing on human skin. Although methods exist for quantifying the alpha-hydroxy acid, glycolic acid in aqueous media, accurate methods for quantification in mixed hydrophobic and aqueous cosmetic creams and lotions are lacking. Glycolic acid was extracted from cosmetics using aqueous tetrahydrofuran (THF), separated with strong-anion exchange cartridges, and quantified by high performance liquid chromatography (HPLC) with UV-VIS detection without the paired-ion reagents. In a recovery experiment, the mean accuracy of the method was 100.6%. The dynamic range of the method allows for the detection of glycolic acid at concentrations used in over-the-counter cosmetics.     

Thermal and physical properties of bakery products

This article reviews the measurement techniques, prediction models, and data on thermo-physical properties of bakery products: specific heat, thermal conductivity, thermal diffusivity, and density. Over the last decade, investigation has focused more on thermo-physical properties of nonbread bakery products. Both commonly used and new measurement techniques for thermo-physical properties reported in the publication are presented with directions for their proper use. Data and prediction models are tabulated for the range of moisture content and temperature of the bakery products.     

LC-UV and LC-MS analysis of food and drink products containing kava

A method for the determination of six kava lactones, methysticin, dihydromethysticin, kawain, dihydrokawain, yangonin and desmethoxyyangonin, in solid foods and beverages has been developed. Solid samples were prepared using methanol extraction, while beverages were extracted using a separate solid phase extraction (SPE) method. After sample preparation, the extracts were analysed using LC-UV or atmospheric pressure photoionization (APPI) LC-MS in the positive mode. Using the method, 10 beverage products, two chocolate products, three unbrewed tea products, three dietary supplements and a drink mix product were analysed. The results obtained using the LC-UV were comparable to those obtained using APPI-LC-MS for most products. Using the SPE method in conjunction with LC-MS, individual kava lactones were detected in drink products at ppb concentrations. Concentrations of total kava lactones ranged between 135-0.035 mg per serving in the food and beverage products tested and between 40-61 mg per serving for the dietary supplement products tested. Results of these analyses as well as extraction efficiency and reproducibility data are reported.     

Kinetics and mechanism of degradation of dichlorvos in aqueous solutions containing reduced sulfur species

Reactions of dichlorvos with five reduced sulfur species (hydrogen sulfide, bisulfide, thiosulfate, thiophenol, and thiophenolate) were examined in well-defined anoxic aqueous solutions to investigate their role in its degradation. Reactions were monitored at varying concentrations of reduced sulfur species over pH range to obtain the second-order reaction rate constants. Experiments at 25 degrees C demonstrated that degradation of dichlorvos promoted by bisufide, thiosulfate, and thiophenolate were of much greater importance than hydrolysis under the experimental conditions in our study. In contrast, hydrogen sulfide and thiophenol were not effective in the degradation of dichlorvos. The activation parameters of the reaction of dichlorvos with bisulfide, thiosulfate, and thiophenolate were also determined from the measured second-order rate constants over a temperature range of 12-50 degrees C. The relative reactivity of the reduced sulfur species decreases in the following order: PhS- > HS- approximately equal to S2O3(2-). When the second-order rate constants at 25 degrees C are multiplied by the environmentally relevant concentration of the reduced sulfur species, predicted half-lives of dichlorvos ranged from hours to days. The results indicated that reduced sulfur species could play a very important role in the chemical fate of dichlorvos in coastal marine environments.