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This study aimed to assess the effect of Persian gum (PG) and microbial transglutaminase enzyme (MTGase) on some physicochemical and microstructural characteristics of low‐fat ultrafiltrated Iranian white cheese during 60 days of cold storage. To manufacture the low‐fat cheese samples, PG (0%, 0.25%, and 0.5%) and MTGase (0, 0.5 and 1 U/g of protein) were used and cheeses (low‐ and full‐fat) without PG and MTGase were considered as controls. The obtained results revealed that the treated samples with PG had a higher titratable acidity, moisture content, and moisture‐to‐protein ratio (M:P), but a lower protein content as compared to the low‐fat control (p ≤ 0.05). Furthermore, the cheese samples treated with the higher level of MTGase (i.e., 1 U/g of protein) had a higher protein and fat content (p ≤ 0.05). Methyl palmitate (C16:0) and methyl oleate (C18:1) were found to be the most abundant fatty acids in the tested cheeses. Additionally, scanning electron micrographs revealed that addition of PG and MTGase improved the microstructure of the samples, so that the sample containing 0.5 U enzyme and 0.5% gum was more similar to its full‐fat counterpart and obtained the highest overall acceptance score among the cheeses. Therefore, our findings revealed that with incorporation of PG and MTGase, a low‐fat ultrafiltrated white cheese could be produced with an appropriate functional, physicochemical, and microstructural characteristics comparable to the full‐fat product. [ABSTRACT FROM AUTHOR]

Cheese is one of the valuable dairy products that has a significant role in feeding most people in society. During or after the production process, cheeses may become contaminated with moulds, which can endanger the health of the product and reduce its marketability. Cheese is one of the foods that has the suitable conditions for the growth of fungi. The purpose of this study was to isolate and identify the contaminants of ultrafiltration (UF) cheeses offered in Fasa city. For this purpose, 110 samples of cheese cans from different factories were randomly collected from the market and kept both open and closed. After growth, moulds were identified morphologically and molecularly. The results showed that the highest contamination of open cheeses was related to Penicillium, followed by Aspergillus, Paecilomyces and Trichoderma. In closed cheeses, Byssochlamys spectabilis was the most contaminated mould. During this study, for the first time in Iran, this type of fungus was isolated and identified. [ABSTRACT FROM AUTHOR]

In this study, the effects of gelatin‐starch (GS) composite coating containing cucumber peel extract (CPE) and cumin essential oil (CEO) were evaluated on the shelf life enhancement of ultrafiltered (UF) cheese during 56 days of storage under refrigerated conditions. The obtained hydroethanolic CPE by the microwave method showed the best results in terms of the total phenolic content, reducing power, 2,2′‐diphenyl‐1‐picrylhydrazyl (DPPH) activity, and 2,2‐azino‐bis‐3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS) radical scavenging activity compared to the immersion and ultrasound methods. The studied treatments were as follows: Control (C), GS, CPE, CEO, GS‐CPE, GS‐CEO, and GS‐CPE‐CEO. Scanning electron microscopic surface morphology of treated cheese samples showed the formation of a firm, integrated, flawless, and homogenous layer on the cheese slices of the GS‐CPE‐CEO treatment. All treatments significantly (p ≤.05) decreased the total viable count, psychotropic bacteria, and yeast–mold population compared to the control group. Adding CEO and/or CPE to GS significantly (p ≤.05) controlled undesirable changes in physical characteristics, such as weight, color, and hardness of the cheese slices. Throughout storage time, the coated cheese slices showed more stable chemical features in comparison to the uncoated cheese samples in terms of moisture, lipid oxidation, pH, and titratable acidity (TA). Sensory evaluation of the preparations showed that the GS coating containing CPE and CEO significantly (p ≤.05) had pleasant effects on the sensory features (taste, odor, texture, and overall acceptability) of the cheese samples during storage time. It was concluded that composite coating of GS containing CPE and CEO could improve the microbial, physical, chemical, and sensory features of ultrafiltration (UF) cheese during refrigerated storage. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Cheese is a dairy product that is popular in the world. Prebiotics and probiotics are increasingly being used to produce potentially symbiotic foods, particularly through dairy products as vehicle. It is well known that both ingredients may offer benefits to improve host health. OBJECTIVES: In this study prebiotic effect of Olive leaf extract or survival of Lactobacillus casei in UF cheese production during 10 weeks storage in cold condition was researched. METHODS: After provision of aqueous extract of olive leaf, probiotic bacteria and starter culture were prepared for inoculation. This extract was added to UF cheese in the presence of the bacteria then, counting of L.Casei on MRSbile agar with pour plate was done during 10 weeks of storage and sensory evaluation was performed after 10 weeks of cheese storage at 4 °C. RESULTS: The number of L. Casei was affected significantly by the addition of OLE (P<0.05). The bacterial growth had a significant relationship with the increase in OLE concentrations (P< 0.05). After 10 weeks, in all probiotic cheese, the concentration of L. Casei was at the level of 106 - 108 cfu/g. Also, sensory quality was positively affected by the presence of OLE in cheese samples. Cheese sample produced with the addition of 0.5% of OLE was the most desirable. CONCLUSIONS: The number of Lactobacillus casei was significantly increased during the storage weeks due to the addition of different concentrations of olive leaf extract. The number of probiotic was increased with increasing concentrations of the extract (P<0.05). Also, positive effects on the sensory properties of cheese samples affected by olive leaf extract were observed and the most common cheese sample was 0.5% of this extract. [ABSTRACT FROM AUTHOR]

In this study probiotic microcapsules with three different shell compositions were produced through enzymatic gelation of skim milk powder by rennet, skim milk powder by transglutaminase and sodium caseinate by transglutaminase. Fabricated microcapsules and free Lactobacillus paracasei cells were incorporated into Iranian UF Feta cheese with different salt levels. Viability of L. paracasei (LAFTI L26), antioxidative capacity, ripening index, titrable acidity, salt content and texture profile analysis (TPA test) parameters including hardness, cohesiveness and stringiness were monitored during 45 days of storage time. Rennet based encapsulation was the most efficient method and could keep L. paracasei viable in all cheese samples (> 7 log10 CFU/g) at the end of storage time. Proteolysis pattern and acidification rate were strongly influenced by shell composition, salt level and storage time. Hardness and stringiness of probiotic cheese samples were influenced by shell composition of microcapsules and storage time but cohesiveness was only dependent on storage time. Therefore, storage time was the only effective factor on free radical scavenging activity of cheese samples. [ABSTRACT FROM AUTHOR]

Background and Objectives: Antimicrobial active packaging with metallic nanoparticles is used as antimicrobial agent in the packaging of food. This study considers the coliform retarding ability of antimicrobial packaging in ultra-filtrated (UF) cheese. Materials and Methods: Plastic films based on low-density polyethylene containing organoclay (cloisite 30B) and different percentages of Ag and CuO nanoparticles produced by extrusion method. Coliform bacteria growth in UF cheese was investigated. The release of nanoparticles from nanocomposite into a food simulant was also assessed. Results: An amount of 3.17-log cfu/g and 0.75-log cfu/g reduction for coliform bacteria obtained for nanocomposite and control films, respectively after four weeks of storage at 4 °C. Nanocomposite film with 1.3% Ag and 2.7% CuO in LDPE matrix introduced as optimum point by Design Expert 7.1.5 software. Microbial model for decreasing growth of coliform bacteria in this product was also determined. Validation of optimum point was carried out using a one-way ANOVA. It was shown that ther is a non-significant (p>0.05) difference with its repeat and a significant (p<0.05) difference with the pure film. Conclusions: Plastic nanocomposite films containing nanoparticle of organoclay and metal can decrease the severity of food processing and application of chemical preservatives in the food industries. [ABSTRACT FROM AUTHOR]

The effect of addition of a commercial enzyme derived from Bacillus Polymyxa type IX on Iranian UF-Feta cheese during a 60- day ripening period on chemical composition, pH and proteolysis of cheese samples was investigated. No Significant differences were observed in the chemical composition between experimental and control cheeses. ​​In experimental cheese, pH values were significantly (P< 0.05) higher throughout whole ripening period and at 60d it was 4.6 and 4.77 in control and experimental cheeses, respectively. Soluble nitrogen in pH=4.6 was significantly (P< 0.05) higher in experimental cheese at 45 and 60d. At 60d, this index was 6.38 and 7.73% in the control and experimental treatments, respectively. Significant difference in the level of trichloroacetic acid (TCA) 12% was also observed at 45 and 60d. Urea- polyacrylamide gel electrophoresis of the pH 4.6-insoluble fractions showed that αs1-casein was hydrolysed faster than the β-casein. Intact αs1-casein values from 100 % on the first day reached to 82.93 % and 71.24 % and in β- casein reached to 90.28 and 90.56% at 60d in control and experimental cheeses, respectively. The concentration of total free amino acids in whole ripening period was significantly (P< 0.05) higher in experimental cheese and at the end of the ripening period was 0.68 versus 0.54 in control cheese (mg Glycine/g cheese). Levels of individual free amino acids were also different between treatments. [ABSTRACT FROM AUTHOR]

Polymer/clay nanocomposites are a group of hybrid materials made from layered silicates of clay dispersed in the polymer matrix with a layer thickness in nanometre. The ability of organoclay nanoparticle including cloisite 15A, cloisite 20A and cloisite 30B incorporated into a low-density polyethylene (LDPE) polymeric matrix was investigated in order to inhibit the growth of coliform bacteria in ultra-filtrated cheese. The number of surviving cells of coliforms was decreased by 2.21 log cfu/g after 4 weeks storage at 4 ± 0.5°C, while pure LDPE showed a reduction of only 0.759 log cfu/g. LDPE film composed of 3% cloisite 15A, 3% cloisite 20A, with no cloisite 30B nano-filler was found as optimum point by combined design approach in design-expert analysis. The resulting film showed coliform load decreased by 2.05 log cfu/g in the optimum point, which was in line with Japanese industrial standard (JIS Z 2801: 2000) about antibacterial effect on coliform bacteria. A suitable microbial model for bacteria growth reduction was also suggested. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Few data are available on the thermophysical properties of cheese in the ripening process. The main objective of this work was to investigate the effects of brining and temperature on the thermophysical properties, i.e., thermal conductivity, specific heat, density and water activity of UF cheese and finally we measure surface heat transfer coefficient. Then we develop models for thermophysical properties based on physical and multiple regression concept. [ABSTRACT FROM AUTHOR]

Nowadays, consumers are interested in cheese produced without chemical additives or high-temperature treatments, among which, protective lactic acid bacteria (LAB) cultures could play a major role. In this study, the aims were to isolate, identify and characterize antilisterial LAB from traditionally produced cheese, and utilize suitable LAB in cheese production. Among 200 isolated LAB colonies, isolate PFMI565, with the strongest antilisterial activity, was identified as Enterococcus durans. E. durans PFMI565 was sensitive to clinically important antibiotics (erytromicin, tetracycline, kanamycin, penicillin, vancomycin) and had low acidifying activity in milk. E. durans PFMI565 and the previously isolated bacteriocin producer, Lactococcus lactis subsp. lactis BGBU1–4, were tested for their capability to control Listeria monocytogenes in experimentally contaminated ultrafiltered (UF) cheeses during 35 days of storage at 4 °C. The greatest reductions of L. monocytogenes numbers were achieved in UF cheese made with L. lactis subsp. lactis BGBU1–4 or with the combination of L. lactis subsp. lactis BGBU1–4 and E. durans PFMI565. This study underlines the potential application of E. durans PFMI565 and L. lactis subsp. lactis BGBU1–4 in bio-control of L. monocytogenes in UF cheese. [ABSTRACT FROM AUTHOR]