Shahram Naghizadeh Raeisi

The study aimed to produce a functional ricotta cheese with chia seed extract (CSE) nanocapsules. First, the CSE was encapsulated using lecithin and basil seed gum, and its characteristics and antioxidant activity (AA) were evaluated. The free CSE (F‐CSE) and encapsulated CSE (E‐CSE) were then added to ricotta cheese formulation (1.5 and 3.0% w/w). The samples were kept for 15 days in a refrigerator and their physicochemical, sensory properties, AA, and oxidative stability were examined. The particle size, polydispersity index, zeta potential, and encapsulation efficiency of CSE nanocapsules were 59.23 nm, 0.328, −44.47 mV, and 80.06%, respectively. The CSE showed remarkable AA in vitro. The AA of F‐CSE was higher than E‐CSE. The moisture, dry matter, fat, and protein content of cheese samples were in the range of 52.64%–53.31%, 46.69%–47.36%, 19.02%–19.28%, and 16.88%–17.02%, respectively. The color of F‐CSE cheeses was slightly yellower than control; however, they did not have clear color differences. During storage, the acidity, hardness, chewiness, and peroxide value of cheeses increased, while the pH, total phenol content, and AA decreased (p < .05). The addition of CSE reduced the rate of pH and acidity changes during storage and significantly increase the AA and oxidative stability. Initially, F‐CSE cheeses had higher functional activity, but on other storage days, due to the protective effect of coating materials, the functional activity of E‐CSE samples was higher. The CSE, especially E‐CSE, did not have an adverse effect on the sensory properties of cheese. Based on the results of this study, it can be concluded that it is possible to manufacture a functional cheese using E‐CSE.

A selection of 36 commercial probiotic fermented dairy products from UK and Europe markets were evaluated for the numbers, types, and viability of Lactobacillus strains against the stated information on their packages. A comparative study was carried out on selectivity of MRS-Clindamycin, MRS-Sorbitol, and MRS-IM Maltose, to select the right medium for enumeration of probiotic Lactobacillus. Based on selectivity of medium for recovery of the targeted lactobacilli, and also simplicity of preparation, MRS-Clindamycin was chosen as the best medium for enumeration of probiotic Lactobacillus in fermented milks. The results of enumeration of lactobacilli showed that 22 out of a total 36 tested products contained more than 10⁶ colony-forming units/g at the end of their shelf life, which comply with the recommended minimum therapeutic level for probiotics. Rep-PCR using primer GTG-5 was applied for initial discrimination of isolated strains, and isolates, which presented different band profile, were placed in different groups. The isolated Lactobacillus spp. were identified mainly as Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus paracasei by analysis of partial sequences of the 16S ribosomal RNA and rpoA genes.

Replacement of milk protein with protein isolates from vegetable resources can significantly influence the characteristics of feta whey less cheese and also decrease the cost of final production. In this study, various blends of milk protein concentrate (MPC) and pea protein isolate (PPI) were mixed at levels of 12% MPC and 0% PPI (MP0), 10% MPC and 2% PPI (MP2), 9% MPC and 3% PPI (MP3), 8% MPC and 4% PPI (MP4), 7% MPC and 5% PPI (MP5), 6% MPC and 6% PPI (MP6) and used in the manufacture of wheyless feta cheese. The chemical, textural, rheological, and sensorial properties, as well as the microstructure of the cheese samples, were evaluated after 1, 15, and 30 days of storage. The general linear model procedure of SAS statistical software was used for statistical analysis. Duncan's multiple range tests was used to compare the means of different treatments. The results showed that all properties of the cheeses were influenced by different levels of PPI due to different total solids content. The use of high concentrations of PPI resulted in a more open protein network, softer structure and decreasing the storage (G′) and loss (G″) moduli in the cheeses. Sensory evaluation of the samples revealed that total score in terms of flavor, texture and overall acceptability was gradually decreased with increasing PPI levels, but still preferable for the panelists. Furthermore, for each sample, with increasing levels of PPI, the whiteness and the greenness were decreased, but the yellowness was increased.

The object of this study was to investigate the possibility of using xanthan gum and flaxseed mucilage as edible coatings for Cheddar cheese during ripening for 90 days. Five samples of Cheddar cheese blocks were coated with different coating materials in triplicate as follows: Coated with polyvinyl acetate as control (C), coated with 0.5% xanthan gum (XG), coated with 0.75% flaxseed mucilage (FM1), coated with 1% flaxseed mucilage (FM2), and coated with 1.25% flaxseed mucilage (FM3). All samples were kept at 8 ± 2 °C in a cold room for 90 days. The statistical analysis of the results showed that the moisture content of the samples decreased and the protein content increased during the ripening period (P < 0.01). The pH, acidity, fat in dry matter, and TCA-SN/TN of samples were significantly affected by xanthan gum and flaxseed mucilage treatment (P < 0.01). The free fatty acid composition of samples was significantly affected by edible coatings. Edible coatings affected the growth of non-starter lactic acid bacteria and the total mesophilic aerobic bacteria in a non-significant manner (P > 0.01). The growth of starter bacteria was significantly altered under the effect of edible coating materials (P < 0.05). Tyrosine and tryptophan contents as an index of proteolysis, lipolysis, and sensory evaluation of samples were not significantly different.