Changes in Sensory Properties, Physico-Chemical Characteristics, and Aromas of Ras Cheese under Different Coating Techniques.

Ras cheese is one of the main hard cheeses in Egypt and is well-known worldwide. Herein, we investigated the potential effects of different coating techniques on the physico-chemical characteristics, sensory properties, and aroma-related volatile organic compounds (VOCs) of Ras cheese over a six-month ripening period. Four coating techniques were tested, including (I) uncoated Ras cheese (the benchmark control), (II) Ras cheese coated with paraffin wax (T1), (III) Ras cheese coated with a plastic film under a vacuum (PFUV; T2), and (IV) Ras cheese coated with a plastic film treated with natamycin (T3). Although none of the treatments significantly affected the salt content, Ras cheese coated with a plastic film treated with natamycin (T3) slightly reduced the moisture content over the ripening period. Moreover, our findings revealed that while T3 had the highest ash content, it showed the same positive correlation profiles of fat content, total nitrogen, and acidity % as the control cheese sample, indicating no significant effect on the physico-chemical characteristics of the coated cheese. Furthermore, there were significant differences in the composition of VOCs among all tested treatments. The control cheese sample had the lowest percentage of other VOCs. T1 cheese, coated with paraffin wax, had the highest percentage of other volatile compounds. T2 and T3 were quite similar in their VOC profiles. According to our GC-MS findings, thirty-five VOCs were identified in Ras cheese treatments after six months of ripening, including twenty-three fatty acids, six esters, three alcohols, and three other compounds identified in most treatments. T2 cheese had the highest fatty acid % and T3 cheese had the highest ester %. The development of volatile compounds was affected by the coating material and the ripening period of the cheeses, which played a major role in the quantity and quality of volatile compounds.

Impact of Salting Techniques on the Physio-Chemical Characteristics, Sensory Properties, and Volatile Organic Compounds of Ras Cheese.

Ras cheese is the main Egyptian hard cheese that is well-known worldwide. Herein, we investigated how different salting techniques affect the physio-chemical properties, sensory properties, and volatile compounds of Ras cheese over a six-month ripening period. Five Ras cheese treatments were made from pasteurized cow's milk using various salting techniques: traditional salting of Ras cheese, salting by applying all of the salt to the curd after the entire whey drainage, salting by applying all of the salt to the curd after half to two-thirds of the whey drainage, salting in a brine solution for 24 h without dry salting, and salting in a brine solution for 12 h and then dry salting. The obtained results by GC-MS recorded that thirty-eight volatile compounds were identified in Ras cheese treatments after six months of ripening, and the development of volatile compounds was affected by the salting technique as well as the ripening period of the cheeses, which played a major role in the type and concentration of volatile compounds. Results revealed that there are six esters, 15 fatty acids, five ketones, two aldehydes, four alcohols, and eight other compounds identified in most treatments. Some physio-chemical characteristics and sensory properties were found to have high correlations with the storage period, while some others have low correlations during the ripening period.