No abstract

Milk fat is a complex natural fat and contains around 400 fatty acids. The objectives of this study were to extract fat from bovine milk using two different methods, including Bligh and Dyer and Mojonnier, and to determine the fatty acid content in the extracted fats using gas chromatography (GC). No differences (p > .05) were detected in the fat content and fatty acids content as a percentage of total fat (FA%TF) extracted using both methods. No differences (p > .05) were detected in some saturated fatty acids (SFAs) and unsaturated fatty acids (USFAs) extracted from both methods, such as C11:0 (undecylic acid), C16:0 (palmitic acid), C18:0 (stearic acid), C14:1 (myristoleic acid), and C16:1 (palmitoleic acid). However, the majority of SFAs were different (p < .05) in Mojonnier method as compared to Bligh and Dyer method and vice versa for USFAs. The short (6.54% vs. 5.95%) and medium (21.86% vs. 20.73%) chains FAs determined by GC were high in Mojonnier fat as compared to Bligh and Dyer fat, while the long‐chain FAs were higher in the last (66.61%) relative to Mojonnier fat (65.51%). This study found that Mojonneir method has resulted in fewer errors. In contrast, the Bligh and Dyer extraction method has more experimental error, which led to decreasing the total fat, as well as was not able to detect C9:0.

Yield, chemical composition, fatty acid profile, and sensory acceptability of Panela cheese produced from cows grazing in an intensive silvopastoral system (ISS) with Leucaena leucocephala and Cynodon nlemfuensis were evaluated and compared with Panela cheese from cows grazing a monoculture system (MS) of C. nlemfuensis only. The experiment lasted for 9 weeks in a tropical area in Mexico using ten crossbred cows (30–90 days of milking) assigned homogenously as five cows in each experimental group. No significant differences were found between the two systems for milk and cheese gross composition. Panela cheese from ISS showed lower content of the hypercholesterolemic fatty acids, accompanied with higher content of omega‐3, omega‐6 and polyunsaturated fatty acids. In addition, Panela cheese from ISS showed higher preference for the attributes of appearance, texture, flavor, and overall acceptability. It is concluded that Panela cheese from cows grazing in ISS has better acceptability and nutritional properties than that produced from MS with grass only.

The composition and quality of probiotic Domiati cheese were studied during 90 days of ripening in brine. Six cheese treatments were made using different types of cultures, which are: C (Control): Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris, T1: as control + Lactobacillus casei, T2: as control +Lactobacillus acidophilus, T3: as control + Lactococcus lactis biovar diacetylactis, T4:Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus and T5:Lactobacillus acidophilus, Bifidobacterium bifidum and Streptococcus thermophilus. A gradual decrease in moisture content was observed as pickling proceeded. Titratable acidity, salt and fat content continuously increased as storage proceeded in all treatments. The soluble nitrogen and amino nitrogen were higher in the probiotic cheese, compared with the control. Enumeration of lactic acid bacteria (LAB) increased up to 45 days of storage and started to decrease with prolonging the storage period. The highest numbers of total bacteria and LAB were detected in T1 and T4, respectively, at the end of the storage, while the lowest was found in T5and T3, respectively. All fresh cheese treatments were found completely free of yeasts and moulds, while it started to appear after 15 days of storage. Absence of coliform bacteria was detected in all treatments. Higher overall scores were achieved in all treatments with added probiotic bacteria compared with control at the end of the storage period. Using probiotic bacteria as adjuncts enhanced the quality and improved the organoleptic properties of the resultant cheese.

No abstract

<p>Intensive silvopastoral systems are being increasingly disseminated in the tropical areas of Mexico, Central and South America, so it is important to know the quality of the animal products generated in these systems. Fatty acid profile of fresh soft cheese (Domiati type) produced from milk of cows grazing <em>Leucaena leucocephala</em> associated with <em>Cynodon nlemfuensis</em> in an intensive silvopastoral system (ISS) was evaluated and compared with a cheese produced from cows grazing a traditional monoculture system (MS) of <em>C. nlemfuensis</em>. The legume <em>L. leucocephala</em> contains phenolic compounds that could affect the fatty acid biohydrogenation in the rumen and therefore the fatty acid profile of resultant milk and cheese. Milk samples from cows in both diets (systems) were processed monthly for cheese making and cheese samples were analyzed for fatty acid profile. The experimental period lasted for 10 months covering the rainy and dry season of a tropical area in Mexico. The results showed that the cheese produced in ISS had significantly lower content (P&lt;0.05) of the saturated fatty acids lauric, myristic and palmitic and significantly higher content (P&lt;0.05) of stearic, linoleic and γ-linolenic acids. Additionally, higher content (P&lt;0.05) of the polyunsaturated fatty acids and omega-6 fatty acids were found in the cheese from ISS. The results suggest that fresh soft cheese produced from silvopastoral systems based on <em>L. leucocephala</em> has a better fatty acid profile than that produced from the traditional MS with grass only.</p>

Lactose is converted to lactic acid through fermentation and ripening of cheese using starter cultures. The content of lactic acid and organic acids formed during storage of cheese is different based on the type of starter cultures, pH, processing, and storage conditions. The objective of this study was to determine the carbohydrates and organic acids of four different commercial cheese samples (Parmesan, Mozzarella, Swiss, and Cheddar cheese) using high‐performance liquid chromatography (HPLC). The lactose content in Cheddar cheese was significantly high ( p < .05) as compared to Parmesan cheese while Mozzarella and Swiss cheese did not have lactose. However, galactose was low in Swiss cheese as compared to other cheese types, while glucose did not detect in all cheese samples. Organic acids such as citric, succinic, lactic, and butanoic acids were high in Parmesan cheese relative to other cheese types. Additionally, pyruvic and propanoic acids were high ( p < .05) in Swiss cheese while acetic and orotic acids were elevated ( p < .05) in Mozzarella cheese relative to other types of cheese.

The daily consumption of high quality foods in Egypt created a situation which is marked with increased quantities of imported foods as well as dairy products to cover the needs of these products. These imported cheeses, which are originated from several sources, allowed us to carry this work out in order to compare these products with the locally-made one. The sampling and analyses of this work were concentrated on products already exist in the market and ready for consumption.70 samples of cheeses were tested in this study. 40 were locally-made, while the count of the corresponding imported samples was 30.An evaluation of the experimental products was carried out by determination of the chemical composition and the microbial counts in each experimental sample with respect to the following main topics9 1-Evaluation of the investigated products according to the fulfillment of the recent Egyptian Standards and 2-Evaluation according to the hygienic quality of this dairy product.These two topics were taken in consideration in order to: a) compare the locally-made with the imported product and/or b) compare the locally-made market products exist under different trading names with each other. Results were as follow: 1-Evaluation according to the fulfillment of the recent Egyptian standards:Generally, the results of this work indicate a complete agreement of the chemical composition of the experimental samples of Edam, Blue veined, Gouda, Cheddar and processed cheeses either locally-made or imported with the Egyptian standards (ES:1183(ES: -3/2005, (ES:1183-2/2005), (ES:1183-1/2005), (ES:1007-2/2005) and (ES:999-2/2005), in the same order. No compositional significant differences were found between the two experimental groups of cheeses 2-Evaluation according to the hygienic quality:The existence of the coliform bacteria was taken as a parameter for a low hygienic quality before *A portion of thesis presented in partial fulfillment of the M.Sc. degree