Egg yolk undergoes an irreversible gelation process at temperatures below −6 °C, which greatly impairs its application and increases its apparent viscosity. This work was aimed to investigate the effect of salt and pH in preventing the gelation of frozen-thawed egg yolk. Before freezing, 5% of salt was added into the pasteurized liquid egg yolk, then pH was adjusted to different levels (5.7, 6.0 and 6.3) with citric acid. After that, the yolk was stored at −18 °C for four weeks. Rheological and thermal properties of the fresh and frozen-thawed egg yolk were measured. In addition, the colour, turbidity and emulsifying properties were also determined. The results showed that pH of all samples increased during frozen storage, but at different rates. The combination of 5% of salt and pH at 6.0 and 6.3 could prevent the gelation, resulting in rheological properties more like the fresh liquid egg yolk. In addition, emulsifying properties also obtained better results for treated yolk. Moreover, L* value of treated egg yolk was higher before freezing and became lower after storage compared to control. The results of this work found that the combination of 5% of salt and adjusted pH could prevent the gelation of frozen-thawed liquid yolk.

In this study, we aim to decrease the fermentation time and to produce low-fat set-type kefir with adequate textural properties using microbial transglutaminase without inactivation. In addition, we reveal the effect of microbial transglutaminase, during and after fermentation, on kefir made with cow, goat, or donkey milk, which is a novel approach. Fermentation is followed by continuous pH and viscosity measurements; the final product is characterized by dry matter content, whey separation, protein pattern, and viscosity parameters, as well as gel firmness. The results show that already 0.5 U/g protein dosage of MTGase decreases pH levels independent of milk type, but MTGase does not influence the kinetics of fermentation. Apparent viscosity could be measured from different stages of fermentation depending on milk type (cow milk, 6 h; goat milk, 8 h; and donkey milk, 9 h). The final product characteristics show that the higher the casein ratio of the applied milk, the better the viscosity and gel firmness of the kefir due to the high reaction affinity of MTGase.

This study investigated the effect of a 2% lactic acid and 2% ascorbic acid mixture, applied via a spray method, on the quality of wild red deer (Cervus elaphus) meat stored under vacuum packaging at 4 ± 1 °C for 21 days. A total of 48 semimembranosus muscle steaks were used, divided into two groups: 24 treated with the acid mixture and 24 non-treated controls. Key parameters, including the pH, instrumental color, bacterial counts, texture profile analysis, and protein degradation (sarcoplasmic and myofibrillar proteins) using sodium dodecyl-sulfate polyacrylamide gel electrophoresis, were assessed on different days. Treated samples exhibited significantly lower aerobic plate counts (p < 0.05) compared to controls. No significant differences in pH were found between the groups, except on day one (p < 0.05). Over time, texture analysis revealed a significant reduction in hardness, cohesiveness, and chewiness in both groups, with treated samples showing greater tenderness. Importantly, the lactic acid and ascorbic acid treatment did not adversely affect the color attributes of the meat. This method shows potential for improving the microbiological safety of venison without compromising its quality, making it a promising preservation technique for the meat industry.

Milk powders are becoming a major attraction for many industrial applications due to their nutritional and functional properties. Different types of powdered milk, each with their own distinct chemical compositions, can have different functionalities. Consequently, the development of rapid monitoring methods is becoming an urgent task to explore and expand their applicability. Lately, there is growing emphasis on the potential of near-infrared spectroscopy (NIRS) as a rapid technique for the quality assessment of dairy products. In the present work, we explored the potential of NIRS coupled with chemometrics for the prediction of the main functional and chemical properties of three types of milk powders, as well as their important processing parameters. Mare, camel and cow milk powders were prepared at different concentrations (5%, 10% and 12%) and temperatures (25 °C, 40 °C and 65 °C), and then their main physicochemical attributes and NIRS spectra were analyzed. Overall, high accuracy in both recognition and prediction based on type, concentration and temperature was achieved by NIRS-based models, and the quantification of quality attributes (pH, viscosity, dry matter content, fat content, conductivity and individual amino acid content) also resulted in high accuracy in the models. R²CV and R²pr values ranging from 0.8 to 0.99 and 0.7 to 0.98, respectively, were obtained by using PLSR models. However, SVR models achieved higher R²CV and R²pr values, ranging from 0.91 to 0.99 and 0.80 to 0.99, respectively.

The consumption of wild red deer (Cervus elaphus) meat is growing due to its nutritional benefits and sustainability. However, challenges like a shorter shelf life and increased microbial load of game meat highlight the need to investigate effective preservation techniques. This study investigated the effects of high hydrostatic pressure (HHP) on the quality parameters of wild red deer meat, including pH, color characteristics, microbial load, texture attributes, and protein stability, assessed on different days. Wild red deer meat was treated with pressures ranging from 150 to 600 MPa, followed by storage at 4 °C for up to 14 days. Results showed that HHP at or above 300 MPa stabilized pH and suppressed microbial growth. On Day 1, the control samples had a microbial count of 4.67 log CFU/g, while treatments at or above 500 MPa reduced microbial levels to below 1 log CFU/g. Texture analysis revealed improved tenderness at lower pressures (150–300 MPa) and enhanced firmness at higher pressures. Color parameters, including lightness and redness, were also influenced by HHP, as lightness increased with pressure, while redness decreased at higher pressure levels. SDS-PAGE analysis indicated protein denaturation, especially at ≥300 MPa, with significant degradation of sarcoplasmic and myofibrillar proteins at ≥500 MPa. These findings suggest that HHP can be an effective method for improving certain quality parameters and extending the shelf life of wild red deer meat up to 14 days of storage, depending on the pressure level applied.

In this study, the effects of crust formation were investigated on the quality properties of pork meat, including texture, colour, cooking loss, pH, water-holding capacity (WHC), and sensory attributes. Two cuts of pork, (1) tenderloin (lean) and (2) collar (fatty), were subjected to three treatments as follows: (1) crusting before cooking, (2) crusting after cooking, and (3) cooking without crusting. Texture was analyzed measuring hardness, cohesiveness, springiness, and chewiness. Colour was analyzed measuring lightness, redness–greenness, yellowness–blueness, and hue angle. Cooking loss and pH and WHC were measured using standard methods and a pressing test. Results showed that meat type and treatment significantly impacted texture, with tenderloin exhibiting greater hardness and chewiness than collar (p = 0.05). Crusting after cooking produced the highest values for hardness and chewiness, while cohesiveness and springiness were unaffected by treatment (p = 0.05). Colour measurements revealed significant treatment-induced differences, with samples crusted after cooking being darker and redder, on average 14% and 33%, respectively. Cooking loss varied considerably, with no significant treatment differences, although a trend suggested lower loss in samples crusted before cooking. pH values were slightly higher in crusted samples, while WHC was notably higher for samples crusted after cooking, likely due to oil retention.