0519 Characterization of queso fresco made with Na/K salt blends and stored for 12 wk

Abstract

Health-conscious consumers are looking for ways to reduce dietary sodium yet want their cheeses to have the flavor, texture, and shelf-life of full-salt cheese. The objectives of this study were to determine the effects of different Na-K salt blends and storage on the compositional, sensorial, microbial, functional, and rheological properties of Queso Fresco (QF), a fresh cheese with a distinct salty taste. QF was made in triplicate on different days with curds from each vat being divided and salted using 1.0% NaCl and 0.5, 1.0, 1.3, or 1.5% added KCl; a 2.0% NaCl QF control and a 0.75%:0.75% Na:K QF were also made. The QF were then stored at 4C for up to 12 wk. Although the variation in salt treatments were in a fairly narrow range, 1.5 to 2.5% total salt, differences (P < 0.05) in some of the QF characteristics were noted. Moisture and ash levels were influenced by salt content while storage impacted moisture and salt levels, water activity, and pH. Only QFs with 1.0% NaCl and 1.3 or 1.5% KCl had sensory saltiness scores similar to the 2.0% NaCl QF control. Loss of free serum from the cheese matrix significantly increased up to 7.5% over the 12 wk of the study with the samples at the higher levels of salt retaining more of the serum in the cheese matrix. Aerobic microbial counts decreased slightly after 2 wk for QF containing > 1.5% salt, and all samples increased 1 to 2.7 logs by wk 10. The variation in the salt content did not alter the non-melt characteristic of the QF samples, while the 2% NaCl QF control had the lowest change in color when baked (130°C for 30 min) and the QF containing 1.0 to 1.5% KCl had the lowest color change when broiled (232°C for 5 min). No significant differences were noted in texture hardness, springiness, or chewiness or in the viscoelastic properties among the treatments or over time. The minor differences in quality traits that resulted in aging QF made with 1% NaCl and 0.5 to 1.5% added KCl showed that KCl substitution was a viable route for reducing sodium in QF. The best overall Na-K blend for QFs were made using 1% NaCl and 1.3 or 1.5% KCl. Findings from this study will help in developing a reduced sodium QF that meets the demand of health-conscious consumers.