Processing of Soft Hispanic Cheese (“Queso Fresco”) Using Thermo‐Sonicated Milk: A Study of Physicochemical Characteristics and Storage Life

Abstract

Queso fresco is a handmade cheese consumed in Latin America and some regions of the United States. However, deficient milk processing has affected its microbial quality and it has an extremely short shelf life and low yield. The objective of this work was to process queso fresco using thermo-sonicated milk; physicochemical parameters were evaluated, including microbial quality during storage (4 °C). An ultrasonic processor (UP400S, 400 W, 24 kHz, 120 μm) was used to sonicate raw milk. Seven milk systems (500 mL each) were evaluated: 1 untreated, and 6 treated at 63 °C/30 min; 63 °C/10 min + sonication; 63 °C/30 min + sonication; 72 °C/15 s; 72 °C/15 s + sonication; and 72 °C/1 min + sonication. A conventional cheese-making process was followed for all systems. The effect of sonication on milk was quite noticeable. Curdling times were reduced considerably, cheese yield (20.6%) was almost doubled, and luminosity of cheese was increased (L*). Textural properties and microstructure images matched very well. Queso fresco processed at 63 °C/120 μm/30 min had the best quality. After storage for 23 d at 4 °C mesophilic count was just 4 log; psychrophilic count, 3.5 log; and enterobacteria count, 3 log. The pH and color remained almost constant and a minor degree of syneresis was observed at end of storage. Due to microstructural rearrangement of the milk components such as fat globules and casein micelles, cheese yield was doubled compared to the traditional handmade product. Shelf life was extended considerably and the product had higher quality.

Novel Edible Coating with Antioxidant and Antimicrobial Activities Based on Whey Protein Isolate Nanofibrils and Carvacrol and Its Application on Fresh-Cut Cheese

“…During storage, cheese shrinkage can cause adverse effects on both product appearance and nutritional quality. In general, coated cheese products have shown better weight loss performance when compared with uncoated counterparts [44]. Figure 6 showed the effects of coating treatment on weight loss of cheese slices during 4 • C storage for 10 days.…”

Modification of the textural and rheological properties of cream cheese using thermosonicated milk

“…This yield was higher than the yield (10.9%) observed in the cheese made with not-sonicated milk (experiment number 9; Table 1). Similarly, Bermúdez-Aguirre and Barbosa-Cánovas (2010) reported that TS of the milk (129 mW mL -1 , 63°C, 30 min) improved the yield of Fresh cheese from 10.7% (control) to 20.6%. These authors also described that the rise in temperature (≥72°C) during TS did not produce a further increase…”

“…The binding of β-lactoglobulin and α-lactalbumin (in a minor grade) with the casein micelles increases the water-holding capacity of the protein matrix (Donato et al, 2007;Vasbinder and De Kruif, 2003), and thus the moisture content of the cheese. Bermúdez-Aguirre and Barbosa-Cánovas (2010) reported also an increase in the moisture content (from 63 to 71%) of Fresh cheese made with thermosonicated milk (129 mW mL -1 , 63°C, 30 min). Nevertheless, these authors concluded that the changes in the water retention of the cheese was an effect of the ultrasound but not of the temperature used during the sonication of the milk.…”

“…These authors found that the clotting time, the curd-firming rate, and the curd firmness were significantly lower when the milk was pre-treated with ultrasound, particularly those treatments subject to longer sonication times. Bermúdez-Aguirre and Barbosa-Cánovas (2010) reported the utilization of thermosonication in the manufacture of Queso Fresco (Bermúdez-Aguirre and Barbosa-Cánovas, 2010). In such work, the Fresh cheese made with milk sonicated (129 mW mL -1 , 63°C, 30 min) showed a reduction in the growth of mesophiles, psychrophiles, and enterobacteria.…”

Ultrasonic Processing for Dairy Applications: Recent Advances

“…Similarly, Reiner et al [98] found superior rheological properties of yoghurts prepared from ultrasonicated milk than the yoghurts prepared from conventionally heated milk. Further, Bermudez-Aguirre et al [18] found only minor changes to the nutritional properties of milk after ultrasound, with the advantage of extending the shelf-life of the product for more than 16 days at 4°C without the use of intensive heat treatments. These tailored functional properties are desirable in the end products.…”