Evaluation of the Effect of Rennet Type on the Texture and Colour of Goats Cheese

Optimization of Microbial Rennet Encapsulation in Alginate - Chitosan Nanoparticles

The milk-coagulating enzyme, rennet, is widely used in cheese making. Recently stabilization of rennet, especially in accelerated cheese ripening, has received considerable interest. As we know encapsulation is one of the enzyme immobilization methods, which could increase enzyme stability. In this study, the effects of alginate, chitosan and, CaCl₂ on rennet encapsulation were evaluated and optimized using RSM. Under the optimal conditions alginate, chitosan, and CaCl₂ were 0.04%, 0.1%, and 0.1% respectively. At the optimum point, encapsulation efficiency, particle size, and zeta potential were evaluated to be 61.8%, 323 nm, and 25 mV, respectively. The effect of temperature and pH on the enzyme activity was evaluated, and the results showed that encapsulated enzyme had higher activity at various pH and temperature in comparison with the free enzyme. Also, the enzyme release data in all pH values were fitted to Korsmeyer-Peppas model and the n exponent indicated that the release mechanism was Fickian. The electrostatic interactions between enzyme, alginate, and chitosan were confirmed by infrared spectroscopy. No statistical difference was found between the K_m and V_max of encapsulated and free enzymes.

Effect of the Ripening Period and Intravarietal Comparison on Chemical, Textural and Sensorial Characteristics of Palmero (PDO) Goat Cheese

Palmero cheese is an artisanal dairy product from the Canary Islands (Spain), awarded with the Protected Denomination of Origin (PDO) from the European Union. It is made with raw milk from the Palmera dairy goat on La Palma island. The aim of this research covered the physicochemical and sensorial characterization of Palmero cheese along 90 days of ripening. Palmero cheeses from four cheese factories were analysed for basic physicochemical parameters, instrumental texture and colour and sensorial profile. Most of the basic composition and the texture and colour attributes of Palmero cheese changed significantly along maturation. During the 90 days of ripening an increase in hardness, fracturability and gumminess (p < 0.001) occurred while elasticity decreased simultaneously (p < 0.001). The internal lightness value decreased significantly (p < 0.001), while yellowness increased (p < 0.001) during cheese ripening. Ripening time affected six of nine sensorial texture characteristics and the entire odour and flavour parameters analysed (p < 0.001). Regarding to intravarietal comparison, in general, cheeses from the four dairy plants showed similar composition although significant differences were detected on textural, colour and sensorial characteristics.

Mold-Ripened Soft Cheeses Fortified with Date Palm Fruit Product as Functional Dairy Products

Date fruit based products are gaining popularity among the consumers in almost all date growing countries due to its added nutritional value. Therefore, novel products were developed by combining two types of foods i.e., soft ripened cheeses and date fruit syrups or date powder. This study is the first to report the surface mold-ripened cheese production with date syrup and date powder. Model cheeses were prepared from pasteurized milk inoculated with Streptococcus thermophilus, Penicillium camemberti and Geotrichum candidum. Date syrup-1, date syrup-2, date powder or the date mixture were added at the stage of curdling. Based on the kinetic growth of the microbial groups in all the treatments, there was no change in the growth of these in various date palm product. On the contrary It may be said that addition of the date fruit product supports their growth. After 35 days, the amounts of total poly phenols were 128.3 ± 1.01, 81.8 ± 1.11, 33.5 ± 2.19, 156.23 ± 1.27 mg GAE/100 g in the cheeses support with date syrup-1, date syrup-2, date powder or the date mixture, respectively. Antioxidant activity of date fruits ranged from 80.13 IC50 (date syrup-2) to 82.23 IC50 (date syrup-1). Based on the chemical characteristics and sensory analysis, the study results showed the potential for innovative application of date products for developing new functional dairy products as an ideal medium for the delivery of biological active compounds with beneficial health effects over.

Influence of diet and rennet on the composition of goats’ milk and cheese

Dry matter, protein, fat, pH, mineral (Na, K, Ca and Mg) and trace elements (Fe, Cu, Zn and Se) concentrations were determined in samples of goats’ milk and in fresh, semi-hard and hard cheeses to study the effect of the goats’ diet and the type of rennet used for the cheese processing of the Palmero Protected Designation of Origin cheeses. Two groups of 20 Palmero goats were fed 2 different diets: a Palmero diet (PD supplied by native forages adapted to subhumid areas, which had a high ratio of long fibre to concentrates (65:35), and an actual diet (AD), the most commonly used by goat farmers, with a low ratio of long fibre to concentrates (35:65). In general, the cheese samples from goats fed with PD had higher mean Ca, Zn, Cu and Se concentrations than the samples obtained from AD fed goats. The diet exhibited a greater influence on the chemical composition of the cheeses than the rennet used in their production. Applying a stepwise linear discriminant analysis a complete percentage of correct classifications of the three types of cheeses according to the diet of the goats was observed.

Physicochemical analysis of full-fat, reduced-fat, and low-fat artisan-style goat cheese

The objective of this study was to examine the physicochemical properties of cheese elaborated via traditional artisan methods using goat milk containing 5, 1.5, or 0.4% fat and ripened for 1, 7, 14, or 28 d. Seventy-two cheeses were produced (2 batches x 3 fat levels x 4 ripening times x triplicate). Proximal composition, pH, texture analysis, and color were recorded in each cheese. Protein and moisture were increased in cheese, and fat and fat in DM were decreased with decreasing fat in milk. Internal and external pH was higher in low-fat and reduced-fat cheese, and pH values decreased during the first 2 wk of ripening but increased slightly on d 28. Cheese fracturability, cohesiveness, masticability, and hardness increased with decreasing fat, whereas elasticity and adhesiveness decreased. Cheese lightness and red and yellow indexes decreased with decreasing fat content; during ripening, lightness decreased further but yellow index increased.