Effects of Critical Storage Temperatures on Microbiological, Physico-chemical and Sensory Indicators of Sweetened Condensed Milk

Background and Objective: Principles of osmo and thermoanabiosis are used to produce sweetened condensed milks. Regarding their extended shelf lives, there are demands for their export to countries with various climates. However, high-positive and low-negative ambient temperatures during sweetened condensed milks transportation can affect their quality. Hence, it is important to study effects of critical storage temperatures on microbiological, physicochemical and sensory indicators of sweetened condensed milks. Material and Methods: This investigation included a comprehensive study of the physicochemical, microbiological and sensory characteristics of sweetened condensed milks after storage under conditions involving multiple-stage and single-stage temperature changes within various ranges (from 5 to 50 °C; from 5 to -50 °C, from 50 to -50 °C and reverse cycles.). Results and Conclusion: Analysis of samples subjected to cyclic changes, including multiple-stage heating for 9 d followed by multiple-stage cooling for 11 d, revealed that only viscosity changed relative to the control samples. In the reverse similar cycle (cooling to heating), formation of destabilized fat was observed. Moreover, changes of cycles and subsequent storage of the samples for 6 m led to increased viscosity, compared to control samples. It was established that single-stage freezing with a 14-d storage did not critically affect its quality. In contrast, rapid heating of the sweetened condensed milk up to 50 °C and storage under such critical conditions outside a cooled storage area were unacceptable. Further storage of samples subjected to cycles of single-stage freezing and heating for 6 m demonstrated a complete non-compliance with control samples for all parameters. Thus, sweetened condensed milk can be subjected to single-stage freezing to -50 °C and storage for 14 d, as well as multiple-stage cooling/freezing to -50 °C and multiple-stage heating to 50 °C following by cooling to 5 °C without loss of quality and safety during 6 m. Conflict of interest: The authors declare no conflict of interest

Bioinformatic Modeling (In Silico) of Obtaining Bioactive Peptides from the Protein Matrix of Various Types of Milk Whey

Whey is a by-product of the production of various types of cottage cheese and cheese, casein, and coprecipitates. Conditions of milk coagulation directly affect the physico-chemical properties of whey and the formation of its protein profile. This fact makes it difficult to standardize the protein profile of milk whey for its further processing. Whey proteins have a great potential to release a wide range of bioactive peptides (BAP), capable of reducing the risk of a number of chronic food-related diseases. Computer modeling of an enzymatic hydrolysis of proteins is one of the ways to increase the efficiency of BAP release studies and to reduce the number of labor consuming experiments. This research is aimed at generating a digital model of the peptide complex of different whey types with predicted bioactivity, safety, and sensory properties using bioinformatic modeling approaches. The study was performed with the use of the proteomic databases tools according to the algorithm of hybrid strategy of bioinformatic modeling developed earlier. As a result of the study, taking into account the ranking of the proteins ratio in the protein profile, the hydrolysis by the protease complex chymotrypsin C-subtilisin was characterized as the maximum efficacy method to release peptides with both antioxidant and ACE-inhibitory activity. It was also observed that the bioactive peptides obtained as a result of in silico hydrolysis after GI digestion simulation can be considered safe in terms of allergic reactions and toxicological effects

Effect of <i>CSN3</i> Gene Polymorphism on the Formation of Milk Gels Induced by Physical, Chemical, and Biotechnological Factors

During the last decade, research into genetic markers in the casein gene cluster has been actively introduced in cattle breeding programs. A special interest has been paid to the polymorphism of the CSN3 gene, responsible for the expression of the k-casein, playing a key role in protein coagulation, interaction with whey proteins, stabilization, and aggregation of casein micelles. This paper aimed to determine the effect of CSN3 genetic polymorphism on acid; rennet; acid–rennet; heat- and acid-induced as well as heat- and calcium-induced coagulation in skimmed milk; and protein-standardized milk systems (UF, NF, RO, VE). The influence of polymorphic variants of the CSN3 gene on the coagulation ability of milk proteins was assessed by the particle size of casein micelles, protein retention factor in the clot, and coagulation ability (duration of induction period, mass coagulation period, dynamic viscosity in gel point). The correlation between CSN3 gene polymorphism and protein coagulation was revealed. Milk systems obtained from CSN3 BB milk were found to have the shortest duration of coagulation, formation of better gel strength values, and increased yield compared to CSN3 AA. This study will improve the efficiency of milk processing and optimize the technology of dairy product production