Mendelian randomization analysis of causal relationship between cheese intake and diabetic retinopathy

AIM:To assess whether there is a possible causal link between the intake of cheese and the risk of diabetic retinopathy(DR)utilizing a two-sample Mendelian randomization(MR)analysis.METHODS:The research data were obtained from summary statistics of genome-wide association studies(GWAS).Genetic loci closely related to cheese intake were extracted as instrumental variables(IVs),and DR was the outcome variable.The data were extracted from individuals of European ethnicity.The data of cheese intake consisted of 451486 samples with 9851867 single nucleotide polymorphisms(SNPs),while the DR data consisted of 206234 samples with 16380446 SNPs.Sixty-one genetic loci closely related to cheese intake were selected as IVs.MR analysis was performed by inverse-variance weighted(IVW)method and MR-Egger regression respectively.The causal relationship between cheese intake and DR was evaluated using odds ratios(ORs)and 95%confidence intervals(CIs).Egger-intercept test was used to test horizontal pleiotropy and sensitivity analysis was performed by leave-one-out test.RESULTS:The P value of the IVW method was less than 0.05,indicating a significant negative correlation between cheese intake and DR.MR-Egger regression showed that the intercept was 0.01 with a standard error of 0.022,and a P-value of 0.634,indicating no evidence of horizontal pleiotropy affecting the IVs related to the exposure factors.Besides,heterogeneity tests confirmed the absence of heterogeneity,and the“leave-one-out”sensitivity analysis demonstrated that the results were stable.CONCLUSION:Cheese intake is causally negatively correlated with the occurrence of DR,and cheese intake could reduce the risk of DR.

用Cream Cheese生产芝士酱的工艺条件研究

以cream cheese为原料,利用原料自身特性,借助于发酵促进剂先进行乳酸发酵,形成cream cheese发酵液。然后与奶粉、变性淀粉等添加物溶液混合后,升温熬制,开发出一种新型芝士酱。通过对cream cheese等物料配比、发酵时间、加糖量及熬制时间进行对比实验,并主要从感官和质构上进行评价,最终确定出理想的工艺配方为:cream cheese与浓度5%含糖量的发酵促进液的质量比为20∶5,进行发酵1h可明显改善芝士风味,获得理想的cream cheese发酵液。该发酵液与其他物料的配比为20∶80,白砂糖添加量为总物料重量比的5%,熬煮时间为40min,可制得理想的芝士酱。

利用大豆蛋白制作模拟干酪(cheese analogs)的研究进展

综述了植物蛋白,特别是大豆蛋白制作模拟干酪的研究进展。热处理的大豆蛋白能大幅度地增加大豆蛋白与酪蛋白的凝结效果,蛋白的微粒倾向聚结,并粘附于酪蛋白分子上。干酪在微观结构上微孔更大,结构更松散,经酶改性的大豆分离蛋白制作的混合干酪弹性、咀嚼性、融化延展性明显提高。

Cream Cheese加工工艺对其品质的影响

采用三因素二次正交旋转组合设计对cream cheese加工工艺进行优化,研究原料乳中蛋白质与脂肪的比例,切块大小,排乳清的pH值对干酪产率,硬度,感官评价的影响。结果表明:Cream Cheese产率较理想的生产条件是蛋白质与脂肪的比例0.43,切块大小9 mm,排乳清的pH值4.64;硬度较理想的生产条件是蛋白质与脂肪的比例0.57,切块大小6 mm,排乳清的pH值4.75;感官评价得分较理想的生产条件是蛋白质与脂肪的比例0.40,切块大小为8 mm,排乳清的pH值为4.68。

FTIR Analysis of Protein Secondary Structure in Cheddar Cheese during Ripening

Proteolysis is one of the most important biochemical reactions during cheese ripening.Studies on the secondary structure of proteins during ripening would be helpful for characterizing protein changes for assessing cheese quality.Fourier transform infrared spectroscopy(FTIR),with self-deconvolution,second derivative analysis and band curve-fitting,was used to characterize the secondary structure of proteins in Cheddar cheese during ripening.The spectra of the amide I region showed great similarity,while the relative contents of the secondary structures underwent a series of changes.As ripening progressed,the α-helix content decreased and the β-sheet content increased.This structural shift was attributed to the strengthening of hydrogen bonds that resulted from hydrolysis of caseins.In summary,FTIR could provide the basis for rapid characterization of cheese that is undergoing ripening.

Effect of Sodium Chloride on Meltability of Mozzarella Cheese

Meltability is one of the most important properties of Mozzarella cheese, as it is generally used in pizza and other foods. Mozzarella was prepared by no salted and immature production technology, and the effect of different addition amounts of salt on the meltability of mozzarella cheese was measured by Schreiber method and small amplitude oscillatory shear analysis（SAOSA） method. The results showed that different adding amounts of NaCl had significant influence on the meltability of Mozzarella cheese, and 2% NaCl addition was the best condition. The results measured by the methods of Schreiber and SAOSA were basically same： adding different amounts of NaCl had significant influence on the hardness and elasticity of mozzarella cheese, but no significant influence on the sticky. It was a good microscopic structure arrangement of Mozzarella cheese with 2% NaCl addition. Scanning electron micrographs showed that a space grid structure formed by casein had changed, and formed many uniform molecular holes. The results indicated that different addition amounts of salt had influence on meltability of no salted immature Mozzarella cheese, and this technology could be drastically shorten the processing time.

马苏里拉干酪(Mozzarella Cheese)的生产工艺探讨

介绍生产马苏里拉Mozzarella干酪的制作工艺,研究和探讨了最佳工艺参数,可为国内准备实现马苏里拉干酪工业化的生产单位提供参考。

Selection of Lactic Acid Bacteria Isolated from San Simón da Costa Cheese (PDO) in Order to Develop an Autochthonous Starter Culture

Traditional cheeses are an important reservoir of microbial diversity that can have important biotechnological applications, especially with a view to improving the characteristics unique to each type of cheese, and in this respect, starter cultures consisting of autochthonous lactic acid bacteria strains are of particular interest. In the present study, we investigated lactic acid bacteria population diversity in San Simón da Costa cheese (PDO, Galicia, Spain) and found a predominance of the genus Lactobacillus, which by the end of ripening accounted for 78% of the strains isolated in Rogosa agar, around 40% of those in M17 agar and about 10% of those in MSE agar. The main species of lactic acid bacteria identified were Lactococcus lactis subsp. lactis, Lactobacillus casei subsp. casei, Lb. paracasei subsp. paracasei, Leuconostoc mesenteroides and Enterococcus faecalis. Virtually all the strains studied from a technological point of view yielded more than or equal to 0.24 g 100 mL-1 lactic acid. Lactococcus lactis subsp. lactis (SS 194), Lactobacillus paracasei (SS 1695 and SS 1689) and Enterococcus faecalis (SS 1378 and SS 1449) strains exhibited the greatest proteolytic capacity. Based on the overall technological aptitude of the tested strains, we can propose starter cultures and co-cultures that include different combinations of previous strains with a view to manufacturing San Simón da Costa cheese from pasteurised milk.

Evaluation of Correlation between Acid Degree Value and Peroxide Value in Lipolysis of Control and Iron Fortified Caprine Milk Cheeses during 4 Months Storage

Elevation of acid degree values (ADV) and peroxide value (POV) indicates deterioration of nutritional and sensory qualities of dairy products during storage. Iron fortification in bovine milk cheeses in relation to lipolytic parameters and their correlations have been studied, while no such studies have been reported on caprine milk cheeses. The objectives of this study were to evaluate levels of ADV and POV of iron fortified [regular ferrous sulfate (RFS) and large microencapsulated ferrous sulfate (LMFS)] goat milk Cheddar cheeses compared to those of non-fortified control cheese (CC) and their correlations. Three batches of 3 types (CC, RFS and LMFS added) of goat milk cheeses were manufactured and stored at two temperatures (4&deg;C and -18&deg;C) for 0, 2 and 4 months. Iron was supplemented to RFS and LMFS cheeses by 8.23 g and 9.03 g per 9 kg, respectively. ADV and POV were determined using standard methods of examining dairy products (Richardson, 1985) and AOCS (1975) procedures. Results showed that ADV values for CC, RFS and LMFS cheeses for 0 and 4 month storage at 4&deg;C were: 0.67, 0.73, 0.64;1.24, 1.78, 1.58, respectively, indicating significant (P < 0.05) elevations occurred in ADV for all three cheeses during 4 months storage. The cheese samples at 4 months storage showed significantly (P < 0.05) higher peroxide values compared to 0 and 2 month stored ones. The samples stored at refrigeration temperature (4&deg;C) revealed slightly more lipid oxidation than those stored at frozen temperature (-18&deg;C). Significant (P < 0.05) elevations in POV for all goat cheeses stored for 4 months and slight increases in POV at higher temperature implies that the longer time and higher temperature storage can elevate the rate of lipid oxidation in goat milk Cheddar cheeses. Correlations (r) between ADV and POV for the pooled data of three types of the caprine cheeses across storage periods were significant (P < 0.01), while r values of CC cheeses alone were negative. It was concluded that significant correlations exist between extents of lipolysis and lipid oxidation in the caprine milk Cheddar cheeses during 4 months storage.

The Impact of Microbial Transglutaminase on the Quality and Antioxidant Activity of Camel-Milk Soft Cheese

This study aimed at investigating the impact of adding microbial transglutaminase (MTGase) after rennet addition on some properties of fresh soft cheese made from camel milk. MTGase was added to milk at concentration of 80, 100 and 120 U/L after 20 and 30 min of renneting. The chemical composition, yield, hardness, antioxidant activity and sensory properties of cheese were estimated. Enzymatic protein crosslinking was analyzed by SDS-PAGE. Results revealed that MTGase-treated cheeses were higher in moisture and lower in protein content compared to control. In addition, the concentration of MTGase and time of addition significantly (P 0.05) impacted these parameters. Among treated cheeses, samples with 80 U of MTGase and addition time of 20 min were the highest in total solids and protein content. Adding MTGase significantly (P 0.05) increased the cheese yield, however, increased MTGase concentration at any time of addition did not improve it. The electrophoretic patterns of MTGase-cheese proteins showed a reduction in the intensity of caseins bands and the appearance of new protein fractions with high molecular weights. However, the changes in the intensity of the whey proteins bands were not sufficiently clear as caseins. The cheese hardness was significantly (P 0.05) affected by adding MTGase. Cheese containing 80 U of MTGase had the highest hardness value compared to control and other treated samples. The antioxidant activity of cheese was negatively influenced by adding the enzyme. The use of MTGase enhanced the mouthfeel, texture and overall acceptability of cheese. However, the effect of MTGase concentration and addition time was not significant (P > 0.05) on the sensory attributes. In conclusion, adding MTGase to milk at concentration of 80 U after 20 min of renneting is recommended to improve the yield, textural and some sensory properties of fresh soft cheese made from camel milk.

Development and Validation of an Ion Chromatography Method for the Simultaneous Determination of Seven Food Additives in Cheeses

Cheeses are characterized by several chemical-physical properties that make it difficult for the microorganisms growth, consequently. The actual European legislation allows the addition of few food additives in this type of food products. In this work, the entire procedure of extraction, purification, chromatographic separations and quali/quantitative determination of seven food additives (sorbic acid, benzoic acid, lactic acid, acetic acid, nitrites, nitrates and phosphates) was developed and applied for the analysis of different types of cheese (mozzarella, cheese spread, semi-hard and hard cheeses). Through validation procedure it was possible to evaluate the most important validation parameters. Extended calibration curves (r > 0.990) were obtained for all the analyzed compounds. Recovery values ranged from 72.8% to 98.4% and a good repeatability was obtained, with precision levels in the range of 0.03% - 0.11% (n = 6). The potential and feasibility of the method were tested by analysing real samples, such as mozzarella, cheese spread, semi-hard and hard cheeses, confirming that the method is well suited to satisfy the demands for accurate confirmation analyses of seven food additives in cheeses, which is especially valuable in official check analyses and in monitoring schemes.

Effect of Fortifying Camel Milk with Sheep Milk on the Processing Properties, Chemical Composition and Acceptability of Cheeses

This study investigates the properties of cheeses made from camel milk, sheep milk and their mixtures. Cheeses were made using Camifloc enzyme as a coagulant after addition of calcium chloride. Camel＇s milk was mixed with sheep＇s milk at the levels of 25%, 50% and 75%. Then, the cheeses were stored for 21 days in the whey at room temperature （37-40 ~C）. The study revealed that fortifying camel＇s milk with sheep＇s milk improved the processing properties of camel milk for cheese making. The addition of 50% sheep＇s milk to camel＇s milk reduced the coagulation time to about 46.15%. The addition of 25%, 50% and 75% sheep＇s milk to camel＇s milk revealed yield of 13.76%, 21.33% and 26.2%, respectively. However, the cheese made from pure camel＇s milk and sheep＇s milk revealed yield of 10.66% and 23.53%, respectively. There were significant （P 〈 0.001） differences in total solids, protein, fat, ash, acidity and overall acceptability among the cheeses made from different types of milk. The cheeses made from camel＇s milk after addition of 75% and 50% sheep＇s milk were the most acceptable compared to other cheeses. Hence sheep＇s milk could be added to camel＇s milk for improvement of cheese properties.

Obtaining Cheese with Milk Mixture and Inca Peanut （Plukenetia Volubilis）

The Inca peanut, a plant native to the Peruvian Amazon, has an important nutritional contribution to 53% oil and 33% protein [ 1, 2], high content of Omega 3 and 6, Vitamin E. Recent research suggests the nutritional and therapeutic significance of consumption for the control of free radicals [3], being an alternative food to reduce nutritional deficiencies of macro and micronutrients in the diet. The results show that the cheese made from a mixture of milk and Inca peanut （70：20 v/v） 0.15 M of Ca sulphate is of firm consistency, with a clotting time of 9 min and yields 14.56% at 80 ℃, is similar to fresh milk cheese sensory characteristics determined by the test of acceptability. Respect to nutrition cheeses present values of protein and fat （16.3% and, 25.05%, respectively）. Sensory evaluation process cheese 70：30 v/v showed an acceptance of 67% relative to a commercial cheese. The texture profile of the finished product, applying a deformation of 30%, have hardness values for 1.88 N, elasticity 0.08, cohesiveness 0.86, adhesiveness 0.36, gumminess 1.62 and chewiness 0.13.

Probiotic Potential of Autochthone Microbiota from S&#227;o Jorge and <i>Parmigiano-Reggiano</i>Cheeses

For a long time, ripened cheeses have been officially recognized as having human health beneficial properties. However, to date only a few studies have investigated the complex microbiota of S?o Jorge and Parmigiano-Reggiano cheeses in order to identify microorganisms with probiotic potential. Hence, with the purpose of analyzing the probiotic potential of autochthone bacteria from S?o Jorge and Parmigiano-Reggiano cheeses, lactic acid bacteria isolated from both products were isolated and their direct biotic interaction against three bacteria found in the human intestine evaluated. From a total of 225 bacterial autochthone isolates, 67 had synergetic behavior with Bifidobacterium animalis , 34 had no synergetic behavior with Shigella dysenteriae and 33 had antagonistic activity with this human pathogen. Biochemical tests were used to identify these cheese isolates with probiotic potential. Lactobacillus paracasei subsp paracasei Lactobacillus arhamnosus were found in S&#227;o Jorge cheese and Lactobacillus rhamnosus , Lactobacillus buchneri and Lactobacillus curvatus in the Parmigiano cheese. Overall, initial exploratory studies with S&#227;o Jorge cheese seem to show a higher number of potential probiotic agents than those found in the Parmigiano-Reggiano cheese. However, in order to better understand the functional potential of this traditional Portuguese cheese, further confirmatory studies should be pursued.

Compositional, Functional and Sensory Characteristics of Selected Mexican Cheeses

The aim of this study was to describe the compositional, functional and sensory properties of six traditional Mexican cheeses: Panela, Oaxaca, Manchego, Manchego Botanero, Tenate, and Morral. A total of 50 cheeses were analysed. Relevant compositional parameters including pH, aw, proximate composition, NaCl, sugars, lactic and acetic acids, mineral contents, free-amino acid nitrogen, fat acid degree value and total fatty acids were determined. In addition, colour and texture profile analyses of unmelted cheeses and their meltability were investigated. Furthermore, other 30 cheeses were used for a descriptive sensory analysis. Properties of cheeses were described, compared between each cheese, and related to their respective making processes.

Effect of Blueberry on Spreadable Processed Cheese

Blueberry is a kind of wild berry with high nutrition values. It contains a great amount of anthocyanin, organic acid and fiber, which significantly affects sensory evaluation, pH value, texture profile analysis （TPA） and microstructure. This study determined the effect of blueberry pulp on spreadable processed cheese through examining pH value, TPA, microstructure and colordifference. The results showed that increased blueberry content lowered pH value, remarkably transformed microstrucmre and TPA （P〈0.05）. Overloaded fiber in blueberry ruined the network structure of casein gel, thus 10% of blueberry performed better, more than that additive volume, sensory evaluation was worsen and gel structure was spoiled gradually. The blueberry sample lowered L＊, b＊ and slightly increased a＊, resulting in blueberry samples presented light amethyst, while sterilizing samples presented dark pink because of the lost of anthocyanin.

Influence of cooking time and cooling rate on the functionality and microstructure of processed cheese spreads

The objective of this work was to study the influence of cooking time and cooling rate on functionality and microstructure of processed cheese spreads. When the cooking time was 20 min, the hardness and apparent viscosity were increased, and formed a homogenous, dense, and three-dimensional protein network, and a stronger gel was formed at this time. The slow cooling can increase the hardness and apparent viscosity of products, protein wall was thicker, and network was closer, so products can formed a stronger gel structure. The influence of cooking time on the functional properties was more significant than the influence of rapid cooling.

Usefulness of Natural Starters in Food Industry: The Example of Cheeses and Bread

Natural starters have been extensively used for many centuries to make many different fermented food products from different raw materials: Milk, meat, roots, vegetables, etc. The industrialisation of food production at the end of the 19th century necessitated the use of regular selected starters to standardize the organoleptic characteristics of the final product. As a consequence, during the 20th century, there was a decline in the use of natural starters in Western countries except in the production of local cheeses or sourdough breads. The beginning of this new millennium has witnessed a deep change in consumer demand, in pursuit of quality, safety and pleasure. In this context, natural starters could, in the future, play an important role in the development of fermented products. However, food producers and researchers have first to cope with fundamental problems in the understanding of these complex ecosystems. The dynamic evolution of the microbial population inside the natural starter (its resilience, its genetic and physiological aptitudes) and the consequences on the product are still partially unknown. This document reviews a broad range of articles concerning the use of natural starters with a specific focus on cheeses and breads, and discusses the major stakes for local food production and the consumption of typical products.

Effect of Different Amounts of Sodium Chloride on the Meltability of Mozzarella Cheese

The effect of different amounts of salt（NaCl）on the meltability of Mozzarella cheese was measured by Schreiber method and small amplitude oscillatory shear analysis（SAOSA）method.The results showed that different addition amounts of NaCl had significant influence on the meltability of Mozzarella cheese,and2%NaCl addition was the best condition for cheese melting.The results measured by Schreiber method and SAOSA method were basically the same.Adding different amounts of NaCl had significant influence on the hardness and elasticity of Mozzarella cheese but no significant influence on the stickiness.The microscopic structure of Mozzarella cheese with 2%NaCl addition was arranged orderly.Scanning electron micrographs showed the space grid structure formed by casein had changed and formed many uniform molecular holes.

Salt Tolerance of Cheese Culture <i>Lactococcus lactis</i>R-604 as Influenced by Prior Salt Exposure and Lactose Deprivation

Manufacture of some cheeses involves the use of Lactococcus lactis. During processing bacteria are subjected to environmental stresses such as acid and salt osmotic conditions. Identifying procedures and mechanisms to develop resistance to these environmental stresses, specifically salt, is important to improve the culture’s growth and performance during food manufacture and storage. Hypothesis was whether salt tolerance of Lactococcus lactis R-604 can be enhanced. Objective was to study the influence of prior salt exposure and lactose deprivation on salt tolerance of L. lactis. The culture was subjected to mild stress induced by lactose starvation or prior salt exposure for 24 hours aerobically at 30&#176;C. A control was conducted without any stress. Cells that were prior mild stressed by lactose starvation or prior salt exposure were transferred to M17 broth with 5 concentrations of NaCl (0, 1, 3, 5 and 7% w/v) and incubated aerobically at 30&#176;C. Plating was conducted immediately after inoculation and every 24 hours for 5 days in M17 agar supplemented with 0.5% of lactose and incubated aerobically at 30&#176;C for 48 hours. Three replications were conducted. There was no need for lactose to grow this culture in M17 broth and it could tolerate prior exposure to 3% w/v NaCl in media without affecting its growth at different salt concentrations. Culture that was exposed to lactose starvation and then subsequently grown in 3% w/v NaCl, at day 3 showed enhanced salt tolerance which can be recommended as a pretreatment condition for obtaining daughter cells with improved salt tolerance.