Microbiological and compositional status of Turkish white cheese

Results of the chemical and microbiological examination of 38 Turkish white cheese samples are presented. On average, the cheese was characterized by a high moisture and salt content, 58.18 and 3.56%, respectively, and a pH of 4.68. Significant variation was found in these compositional factors, indicating the extreme diversity of manufacturing practices. Microbiological analysis revealed the presence of high numbers of coliforms, faecal coliforms and Escherichia coli, extremely high numbers of faecal streptococci, and a low level and incidence of Staphylococcus aureus, Salmonella and Clostridium perfringens were not isolated from the samples. There was no correlation between the levels of coliforms, faecal coliforms, E. coli and enterococci, suggesting that the enterococci count in Turkish white cheese may not be a good indicator of sanitary practices.     

Prevalence of potentially pathogenic Bacillus cereus in food commodities in The Netherlands

Randomly selected food commodities, categorized in product groups, were investigated for the presence and number of Bacillus cereus bacteria. If positive, and when possible, five separate colonies were isolated and investigated for the presence of four virulence factors: presence of genes encoding three enterotoxins (hemolysin BL [HBL], nonhemolytic enterotoxin [NHE], and cytotoxin K) and the ability to produce cereulide. In addition, the presence of psychrotrophic and mesophilic signatures was determined. The genes for NHE are found in more than 97% of the isolates, those for HBL in approximately 66% of the isolates, and the gene for cytotoxin K in nearly 50% of the isolates. Significant associations between product groups and (combinations of) virulence factors were the relatively low percentage of isolates from the "flavorings" group containing genes encoding NHE and the higher-than-average occurrence of both the genes encoding HBL and NHE in the "pastry" group. Cereulide was produced by 8.2% of the isolates but only in combination with the presence of genes for one or more other virulence factors. Most isolates (89.9%) were mesophilic; minorities of the isolates were psychrotrophic (4.4%) or of intermediate signature (5.7%). In the product group "milk and milk products," the incidence of strains with psychrotrophic or intermediate signatures is significantly higher than in the other product groups. In the product groups "flavorings," "milk and milk products," "vegetable(s) and vegetable products," "pastry," and "ready-to-eat foods," a relatively high number of samples contain high numbers of B. cereus bacteria. Within the product group "ready-to-eat foods," the products containing rice and pasta show a relatively high incidence of high numbers of B. cereus bacteria.     

Compositional Analyses and Shelf‐Life Modeling of Njangsa (Ricinodendron heudelotii) Seed Oil Using the Weibull Hazard Analysis

This study investigated the compositional characteristics and shelf‐life of Njangsa seed oil (NSO). Oil from Njangsa had a high polyunsaturated fatty acid (PUFA) content of which alpha eleostearic acid (α‐ESA), an unusual conjugated linoleic acid was the most prevalent (about 52%). Linoleic acid was also present in appreciable amounts (approximately 34%). Our investigations also indicated that the acid‐catalyzed transesterification of NSO resulted in lower yields of α‐ESA methyl esters, due to isomerization, a phenomenon which was not observed under basic conditions. The triacylglycerol (TAG) profile analysis showed the presence of at least 1 α‐ESA fatty acid chain in more than 95% of the oil's TAGs. Shelf‐life was determined by the Weibull Hazard Sensory Method, where the end of shelf‐life was defined as the time at which 50% of panelists found the flavor of NSO to be unacceptable. This was determined as 21 wk. Our findings therefore support the potential commercial viability of NSO as an important source of physiologically beneficial PUFAs.     

低乳糖芒果风味发酵乳制作工艺研究

以生牛乳、芒果泥为原料,通过试验对低乳糖芒果风味发酵乳产品配方及乳化稳定剂的复配方案进行了研究。结果表明:低乳糖芒果风味发酵乳最优配方为白砂糖8.0%、乳清蛋白粉1.0%、芒果泥5.0%、芒果香精0.04%、乳糖酶0.025%;产品最佳稳定剂为羟丙基二淀粉磷酸酯0.4%、明胶0.15%、琼脂0.1%。在该配方及稳定体组合条件下,可获得口感优良,风味合适,货架期质量稳定的低乳糖芒果风味发酵乳。     

全柳橙营养果酱的研制

以开发全柳橙果酱为目的,对其生产工艺、技术操作要点及影响柳橙果酱质量的因素进行探讨。单因素试验结果表明蔗糖、酸味剂和增稠剂对果酱的质量均有影响。采用正交试验确定了全柳橙果酱的最佳配方为蔗糖:柳橙0.8、柠檬酸0.4%、黄原胶0.05%、羧甲基纤维素钠0.15%。     

Pressing technique and its effect on the quality of Dhaka cheese

Dhaka cheese is a semihard artisanal variety made mainly from bovine milk, using very simple pressing methods. Experimental cheeses were pressed at gauge pressures up to 31 kPa for 12 h at 24 °C and 70% RH. These cheeses were subsequently examined for their compositional, textural and rheological properties plus their microstructures investigated by confocal laser microscopy. The cheese pressed at 15.6 kPa was found to have the best compositional and structural properties.     

高纯度活性大米蛋白的制备

介绍了一种全新的基于杰能科生料水解酶的高纯度大米蛋白的制备.并探讨了在该工艺中酶的选择、pH、温度等不同因素对大米蛋白纯度的影响。结果表明,采用杰能科生料水解酶,在pH5.5,温度60℃,底物浓度20%～25%的条件下,可得到含量在80%以上的大米蛋白,同时生产过程中的糖液质量也可以达到Dx值在95%以上。     

Diversity of the sensory characteristics of traditional dry sausages from the centre of France: Relation with regional manufacturing practice

Quality labelling of traditional products may be based on identifying specific sensory properties and linking these to particular compositional characteristics or manufacturing practices. Methodology to do this in the presence of large sensory variation is required. In order to study the sensory diversity of traditional dry sausages, a typology was performed on the small scale food processing facilities in the centre of France and this identified six types of small-scale facilities with specific manufacturing practice. From these six groups, 15 small-scale facilities were chosen in order to perform a QDA^® test on dry sausages with a panel of 11 trained assessors who used 24 attributes related to appearance, texture, aroma and flavour. The list of attributes used by the panel was composed of terms such as marinade aroma, roast aroma, wine flavour and roast flavour which may be specific to traditional dry sausages. The major variation among the products was related to the type of the raw material used and to the texture of the dry sausages linked to the drying time. Hierarchical cluster analysis on the sensory data led to six groups of traditional dry sausages. These sensory groups did not exactly correspond to the groups given by the typology. However, a high correlation was found by canonical correlation analysis between the typology data and the sensory data on the first factors. Moreover, the discriminant analysis showed that it was possible to classify 100% of the traditional dry sausages into specific manufacturing practice groups based on the sensory data. The methodology used in this study is well adapted for the attribution of quality labels to products manufactured by a group of producers on a defined territory.     

普洱茶风味酸乳制作工艺的研究

以生牛乳为原料,探讨了普洱茶风味酸乳的制备工艺。通过正交试验研究了普洱茶风味酸乳工艺配方及稳定剂的复配方案。结果表明:普洱茶风味酸乳最优配方为普洱茶0.8%、牛奶浓缩蛋白粉0.4%、白砂糖8.0%、红茶香精0.04%,该配方组合可获得口感良好,酸甜适口、风味优良的普洱茶风味酸乳。普洱茶风味酸乳最佳稳定剂组合为乙酰化双淀粉己二酸酯0.4%、明胶0.15%、琼脂0.1%。在该稳定体系条件下,能够提供产品饱满细腻的口感,并保障产品在货架期良好的感官品质。     

模糊数学感官评价法优化香菇酥糖的制作工艺

为优化香菇酥糖制作工艺,获得品质良好的香菇酥糖,采用单因素和正交试验对香菇粒预处理方式和糖液配方进行了研究。用模糊数学评价法评价香菇酥糖品质,对其外观、色泽、滋味与口感、组织结构感官评价权重进行了分析。结果表明:香菇粒最佳预处理方式是菇粒漂烫后在25%麦芽糊精溶液中浸泡3h,糖液的最佳配方是以麦芽糖总量计,玉米淀粉3%,麦芽糊精20%,柠檬酸0.12%,加水量30%。此条件下制作出来的香菇酥糖感官品质好,菇粒含量高,是一种健康的糖果。     

Effects of enzymatic action on the formation of theabrownin during solid state fermentation of Pu-erh tea

BACKGROUND: Theabrownin (TB) is a main bioactive component in Pu‐erh tea, and the total amount is between 100 and 140 g kg^?1. However, reports on the mechanism of formation of TB are sparse because it has a high molecular weight and complex composition. Hence, the mechanism of formation of TB in Pu‐erh tea during solid state fermentation was investigated using an exogenous enzyme method. RESULTS: It was found that, in the presence of exogenous enzymes, the tea liquor prepared from the resulting leaves changed considerably in colour. In addition, the TB, total carbohydrate, polysaccharide, amino acid and protein contents were all increased, while the tea polyphenol content decreased sharply; the surfaces of leaves before fermentation appeared to be smooth and intact, and the structures of the cell, cellulose and lignin were complete, while after fermentation their surfaces were covered by microorganisms and the structures of the cells were largely disrupted. CONCLUSION: The enzymatic actions are closely related to the compositional changes occurring during Pu‐erh tea manufacture, and its quality. Enzymes produced by microorganisms were found to be the main cause of TB formation during the fermentation of Pu‐erh tea. Copyright © 2011 Society of Chemical Industry     

Sensory perception of creaminess and its relationship with food structure

Practical difficulties are frequently encountered in understanding the meaning of creaminess as used as a sensory attribute, and in the compositional and physical characteristics of foods that give rise to creaminess. Selected factors have been investigated in this project. The size of dispersed particles (solid, liquid and gaseous) on the perceived creaminess was of particular interest during the course of the work, and this was varied using appropriate changes in processing, during production of samples for analysis. Additional factors investigated included the presence of an added cream flavour in artificial creams, fat content in artificial creams and air content in chocolate mousses. Sensory characterisation of samples was carried out using sensory profiling, while physical characterisation of the samples was by means of particle size measurements, microscopy and rheology. The results show that perceived creaminess is a complex attribute in multi-phase food systems, being dependent on both flavour and textural characteristics of products, with different dependencies on these characteristics, depending on the product type concerned. The project demonstrated the value of manipulating processing and formulation variables as a means of generating a range of food structures for the investigation of creaminess. It is evident, however, that the concept of creaminess might differ between different structural types, limiting opportunities for devising general rules governing the factors controlling creaminess. Further studies should focus on specific structural types that are open to manipulation, and further research is in progress to investigate systematic changes to a mousse structure.     

Chitosan: antimicrobial activity and potential applications for preserving minimally processed strawberries

In this research the possible use of chitosan coating on fresh-cut strawberries was investigated. Manually sliced strawberries were treated with a solution of 1% chitosan, packaged in modified atmosphere with high (80%) and low (5%) percentage of oxygen and then stored at 4, 8, 12 and 15 °C. Changes in microbiological quality were measured and the shelf life of the samples, as stability time, was kinetically modelled in order to check the effects of storage temperature on the most relevant microbial indices for product quality.A chitosan coating inhibited the growth of microorganisms and affected significantly and positively the stability time of the products, above all when the samples were packaged in modified atmosphere (with low and high percentage of oxygen). Besides, the presence of high percentage of oxygen, combined with chitosan coating, seemed to affect positively the colour.The data revealed that applying a chitosan coating prolonged effectively the quality and extended the shelf life of fresh-cut strawberries.     

An analysis of codon bias in six red yeast species

Red yeasts, primarily species of Rhodotorula, Sporobolomyces, and other genera of Pucciniomycotina, are traditionally considered proficient systems for lipid and terpene production, and only recently have also gained consideration for the production of a wider range of molecules of biotechnological potential. Improvements of transgene delivery protocols and regulated gene expression systems have been proposed, but a dearth of information on compositional and/or structural features of genes has prevented transgene sequence optimization efforts for high expression levels. Here, the codon compositional features of genes in six red yeast species were characterized, and the impact that evolutionary forces may have played in shaping this compositional bias was dissected by using several computational approaches. Results obtained are compatible with the hypothesis that mutational bias, although playing a significant role, cannot alone explain synonymous codon usage bias of genes. Nevertheless, several lines of evidences indicated a role for translational selection in driving the synonymous codons that allow high expression efficiency. These optimal synonymous codons are identified for each of the six species analyzed. Moreover, the presence of intragenic patterns of codon usage, which are thought to facilitate polyribosome formation, was highlighted. The information presented should be taken into consideration for transgene design for optimal expression in red yeast species.     

Raw milk grading using fuzzy logic

In this paper the current raw milk standard specification for Zimbabwe is reviewed. The hygienic quality and the compositional quality parts of the standard are recast in fuzzy logic terms and linked with rule bases to form a structured judgment system for grading both the hygienic and compositional quality. These may also be merged to provide an overall or total quality assessment. The structured judgment system is applied to two raw milk samples from different sources. The data from the one sample yield a higher hygienic quality rating than the data from the other, but a lower compositional quality rating. A total quality rating is found for each of the two samples and compared. The structured judgment system provides a clearer and more comprehensive assessment than the currently used system, and since it embodies an expert system element there is also a conclusive opinion of the grading in the form of membership values of certain sets. It therefore goes farther than the present system as the basis for decision support .     

Prevalence and risk factors for udder cleft dermatitis in dairy cattle

Udder cleft dermatitis (UCD) is a skin lesion in dairy cattle mostly located at the anterior junction between the udder and the abdominal wall or between the front quarters. Relatively little is known about causative factors for UCD, and few studies have investigated prevalence and risk factors of UCD. Therefore, the aim of this study was to investigate the prevalence of UCD in a random sample of dairy herds with freestalls and milking parlors in a county of Sweden. Thirty dairy herds participated in the study. Each herd was visited once at milking, when every third cow was investigated for presence of UCD. Associations between UCD and milk production, breed, parity, days in milk, claw health, and udder health on the herd and cow levels were also investigated. In addition, a case-control study was performed in 6 herds with a high prevalence of UCD to investigate associations between udder conformation or mange and UCD. Udder cleft dermatitis was found in 18.4% of the 1,084 cows included in the study. The within-herd cow prevalence varied between zero and 39%, with an average of 18.5%. Risk factors for UCD at the herd level were a high proportion of Swedish Red cows and a high production level. At the cow level, breed, parity, and production level were identified as risk factors. The highest risk of having UCD was found in high-producing Swedish Red cows that had calved at least 3 times. Veterinary-treated clinical mastitis was associated with UCD, but cow composite somatic cell count was not. A strong anterior udder attachment was a protective factor, but signs of mange had no association with UCD. The primary cause of UCD is still unclear, and more research is needed to identify the best ways to prevent the development of this animal welfare problem.     

Rapeseed meal. II. Chemical composition and biological quality of the protein

The chemical composition (moisture, ash, protein, amino acids, ether extract, crude fibre, Ca, P, Fe, thioglucosides, isothiocyanates and oxazolidinethiones) and biological quality (net protein utilisation, available lysine and digestibility) were investigated in 12 samples of presscake meal of rapeseed (Brassica napus) collected from local factories. Crude fibre and mineral contents were comparatively high. Thioglucosides and their hydrolysis products (isothiocyanates and oxazolidinethiones, which are toxic) were found in high concentrations. All samples showed a high protein content and their amino acid patterns corresponded to a good-quality protein with a score of 80, and an adequate level of available lysine. Nevertheless, the biological quality measured as net protein utilisation and digestibility gave low values, which could be explained on the basis of the presence of the toxic factors and the high level of crude fibre, respectively.     

芒果低糖果酱的研制

本文研究了具有营养保健功能的芒果低糖果酱的加工工艺.采取增稠剂的添加量,果浆与砂糖的比例及柠檬酸的添加量三个因素的三个水平进行正交试验,结果表明,增稠剂添加0.2％,果酱与砂糖的比例为5∶2,柠檬酸的添加量为0.15％,可以制得品质优良的芒果低糖果酱.此条件下制得的果酱酱体良好,质地细腻,呈金黄色并有浓郁的芒果香味,酸甜可口,营养丰富.     

猕猴桃等添加物改良面条加工品质及强化营养品质研究

为改善面条加工品质和强化营养品质,以陕优225小麦品种粉为面条粉材料,以猕猴桃粉、核桃粉、大豆粉为添加材料,研究添加物对面条加工品质和营养品质的影响;以国际通行的优质面条专用技术标准为依据,进行新的工艺研究。试验结果表明,添加物在一定程度上可以改善面条品质,尤其能够丰富面条的营养物质,改善和强化面条的营养品质。在单因素试验中,猕猴桃粉、核桃粉和脱脂大豆粉效果较好。在以上3种添加物为因素的正交试验中,大豆粉对面条影响最大,核桃粉次之,猕猴桃粉的影响最小,3种添加物最佳配比是猕猴桃粉添加量为面粉的3%,核桃粉为4%,大豆粉为4%。     

Formulation,Evaluation and Optimization of Tortillas Containing Wheat,Cowpea and Peanut Flours Using Mixture Response Surface Methodology1

The performance characteristics of tortillas, prepared with different composite blends of wheat, cowpea and peanut flours, were evaluated by mixture response surface methodology. Optimum wheat flour substitution levels were determined. Results indicated that wheat flour could be successfully replaced with up to 24% cowpea and 46% defatted peanut flours and result in tortillas with quality characteristics comparable to those from 100% wheat. Sensory evaluation indicated that beany flavor was the most limiting attribute. Sensory attributes correlated significantly with physical and compositional measures of tortillas and physical measures of tortilla dough.