جستجوی مقالات مرتبط با کلیدواژه « خصوصیات میکروبی » در نشریات گروه « صنایع غذایی »

Process cheese is a combination of cheese and emulsifying salts, that has a homogeneous and uniform texture under heat influence. Labneh is one of a type of the processed cheese that uses yogurt as well. In this study, the effect of adding 0.2% carrageenan and pectin hydrochloride to the composition of Labneh was evaluated in 1, 40 and 80 days after production, in terms of physicochemical, microbial and sensory parameters. The results of the test were analyzed by SPSS software version 22, using variance experiments in a completely randomized design with factorial arrangement. The results showed that the effect of adding carrageenan, pectin and storage time on the physicochemical properties of dairy cheese was significant. The pH of all the treatments were decreased significantly until 80th day. During storage days, the dry matter of the samples which contained hydrochlorides, had a significant change compared to the controlled sample. The results of texture properties test showed that the hardness, adhesiveness, cohesiveness and springiness of the texture of the products were changed by adding hydrochlorides. Pectin treatment had the lowest hardness and adhesiveness until the day of 80th . The springiness of the carrageenan treatment was increased significantly, and the cohesiveness increased significantly by addition of the carrageenan and pectin. The results of persistence of the product showed that the samples were within the standard allowable range during the storage period, in terms of total counts of microorganisms, mold and yeast. In sensory assessments, pectin-containing treatments got high score of hardness, spreadability and overall acceptance, but did not differ significantly in taste and color from other treatments.

In this study, active polyethylene films containing silver nanoparticles to increase the shelf life of mushroom were produced. For this purpose, silver nanoparticles with different levels (0, 0.5, 1, 2 and 3% based on polymer weight) were added and its effect on the characteristics of the mushroom, microbial characteristics and sensory properties was evaluated. Mushrooms were stored at 4 °C for 12 days and physicochemical characteristics were analyzed after 0, 4, 8 and 12 days of storage. Increasing the concentration of nanoparticles in the polymer structure leads to decreasing weight loss and total soluble solid changes in mushroom samples compared to the control sample. The increasing the concentration of silver nanoparticles significantly (p<0.05) reduced the loss of firmness in the samples. The L* value changes of the mushrooms coated with polymer-silver nanoparticles was lower than the control samples. A significant (p<0.05) decrease in L* value and a significant (p<0.05) increase in a and b values occurred in all mushrooms during the maintenance period. The use of polymer-silver nanoparticles coating led to significant (p<0.05) decrease in number of microorganisms of the mushrooms during all days of storage compared to the control sample. Incorporation of silver nanoparticles caused decrease in microbial count of the coated samples. In all treatments, increasing the silver nanoparticles level caused to improve the physicochemical, microbial and sensory properties of mushroom samples. Based on sensory evaluation was found that using the polyethylene film containing 3% the silver nanoparticles led to significantly increasing (p<0.05) of sensory parameter scores, so that the treatment wrapped with the polymer containing 3% the nanoparticles had the highest acceptability score (5 out of 5) compared to control and other treatments. Overall it can be concluded that utilization 3% silver nanoparticles in the polymer structure resulted in the desirable physicochemical and microbial quality and sensory properties in the mushroom samples.

A synbiotic yogurt was provided by adding aerobic (Lactobacillus acidophilus) and anaerobic (Bifidobacterium bifidum) probiotics and inulin to the yogurt. The effects of aerobic and anaerobic probiotics, storage time, and inulin on the physicochemical/microbial properties of synbiotic yogurt in terms of acidity, viscosity, syneresis, and microbial count were studied. A head-space solid phase microextraction-gas chromatography (HS-SPME-GC) method was used to extract and detect of VOCs profile (total peak area and total peak height) of yogurt sample by nano-sized polyaniline fiber. The D-Optimal Combined Design (DOCD) was used to analyze the effect of probiotics type (aerobic and anaerobic), inulin percent (W/W %), and storage time of yogurt (day) on the physicochemical/microbial properties of synbiotic yogurt. Results showed that the aerobic and anaerobic probiotics, inulin, and storage time of yogurt affect the yogurt physicochemical/microbial property and there were relations between the physicochemical/microbial properties of yogurt and VOCs gas chromatography profile (total peak area and total peak height). The current research also enables us to obtain microbial count by total peak area and total peak height of the VOCs GC-profile of yogurt sample.