Interference of lactose and sucrose in refrigerated storage of firm consistency yogurtsInterferência da lactose e sacarose no armazenamento refrigerado de iogurtes de consistência firme

This study aimed to produce quail egg powder by freeze-drying and to evaluate its stability in different types of flexible packages (low-density polyethylene, polypropylene and pigmented polypropylene) in high relative humidity (approximately 81%) at 25 °C during 59 days. The packages were evaluated for water vapor permeability and freeze-dried egg was characterized as to bulk density and hygroscopicity (initial time), and moisture, water activity, pH and color (until the end of storage). GAB, BET and Peleg sorption isotherm models were adjusted to the experimental data to predict monolayer moisture content in the powdered eggs. The freeze-dried quail eggs presented a little oscillation in color coordinates, reduction in pH, and increase in moisture content and water activity during storage for all packages used. No evaluated packaging was sufficiently effective as a moisture barrier. GAB and BET models fitted better to the experimental data for the freeze-dried quail egg, and the estimated monolayer moisture values were 0.0333 and 0.0227 g H2O/g solids, respectively. The powdered quail egg has industrial potential, however, it is susceptible to significant changes throughout storage when exposed to high relative humidity and conditioned in the tested packages. Commercially, as this product can be sold in regions with different temperatures and relative humidity, it is essential to consider the use of preservatives or anti-wetting agents.

Background Quail eggs have nutritional, therapeutic, and functional potential but are still not widely consumed globally. Their availability in powder form can contribute to expanding their consumption worldwide. However, drying can significantly affect their properties. To the best of our knowledge, there is no study comparing the effect of drying methods on the rehydration capacity and functional properties of whole quail egg powder. In this context, this work aimed to obtain powdered quail eggs by convective oven drying and freeze drying of eggs in liquid and foam form, to evaluate the effect of each drying method on their physical, rehydration, and functional characteristics. Results The powder obtained by freeze‐drying eggs in the liquid form (L‐FD) showed the most desirable foaming capabilities; however, it produced less stable emulsions. The powder obtained by convective oven drying of eggs in liquid form (L‐CONV) had the worst rehydration and foaming capabilities but produced firmer gels and had good emulsifying capacity. Finally, the powders obtained by foam‐mat drying yielded very stable foams and emulsions. Conclusion The methods for quail egg powder production that were evaluated performed well. The results point to the strong potential of quail egg powder as an ingredient. Liquid freeze‐dried (L‐FD) eggs stood out for their rehydration capacity. Each powder had different functional properties, so the choice of the best method depends on the intended application of the powder as specific characteristics and functional properties are suitable for preparing each food. © 2022 Society of Chemical Industry.

Due to the large number of people with lactose maldigestion, the dairy industries have increased production and diversity of low lactose and lactose-free foods. Consequently, the need to control the lactose hydrolysis process has also risen. This study aimed to correlate freezing point depression (cryoscopy) and lactose concentration, quantified by high-performance liquid chromatography (HPLC), in UHT milk. To accomplish this, UHT milk samples were subjected to seven lactose hydrolysis treatments, using lactase enzyme, resulting in different lactose concentrations. All samples were subjected to HPLC analysis and freezing point measurement, using a cryoscope. The results were plotted on a graph and a linear regression was performed. There was a strong correlation between lactose concentration and freezing point (R = 0,9973) and the coefficient of determination (R2) was 0,9946, which means that 99,46% of the variability of the response data is explained by the linear regression model. Therefore, the results point to the feasibility of estimating the lactose concentration in milk during the hydrolysis process for the production of low lactose milk, by cryoscopy, a quick analysis, with lower cost compared to HPLC and that is already among the analyses commonly performed in dairy industries.

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