Andrea Sarrica

Probiotics are increasingly used to promote oral health, with Lacticaseibacillus rhamnosus demonstrating proven effectiveness. Additionally, Heyndrickxia coagulans shows promising potential in this field. Chewing gum has recently been proposed as an innovative delivery method for probiotics. This study aimed to evaluate the kinetics in saliva of Heyndrickxia coagulans SNZ1969^® and Lacticaseibacillus rhamnosus GG in microencapsulated and non-microencapsulated forms (LGG^®) following their administration via sugar-free chewing gums. A randomized cross-over trial was conducted involving 10 volunteers. Participants chewed gums containing one of the probiotic strains for 10 min. Saliva samples were collected at baseline (T₀) and six subsequent time points over 2 h (T₁–T₆). Colony-forming units (CFUs) were identified and quantified. The Tukey’s range test was applied to make pairwise comparisons between different probiotics at every time point, between different time points of the same probiotic, and between the area under the curve describing the kinetics of different probiotics in saliva. At T₁, all probiotics exhibited peak counts, followed by a gradual decline until T₆. H. coagulans SNZ1969^® achieved the highest counts at T₁, T₂, and T₃ (mean log₁₀ CFU/mL: 6.1 ± 0.5; 5.8 ± 0.5; 5.6 ± 0.5, respectively), while the non-microencapsulated form of LGG^® peaked at T₄, T₅, and T₆ (mean log₁₀ CFU/mL: 4.0 ± 0.7; 3.8 ± 0.9; 3.3 ± 1.3, respectively). The participants reported no adverse effects. Probiotics were detectable in saliva up to 2 h post-administration via chewing gum, indicating its suitability as a delivery vehicle. However, significant variability was observed among participants.

Hydrocolloids are long-chain biopolymers that can form viscous solutions or gels when dissolved in water. They are employed as rheological modifiers in various manufacturing processes or finished products. Due to its unique gelation properties, animal gelatin is one of the most widely used hydrocolloids, finding applications in several fields such as food, pharmaceutical, and photographic. Nowadays, the challenge of finding valid alternatives to animal products has become a crucial issue, for both ethical and environmental reasons. The aim of this work, is to propose a green hydrocolloidal network, able to reproduce the gelation features of animal gelatin gels. κ-carrageenan gels may be an interesting alternative to gelatin, due to their attractive gelling features. We investigate the thermorheological behavior of κ-carrageenan aqueous solutions at various concentrations, focusing on gel features such as transition temperature and gel strength. To improve the viscoelastic response of such gels, we add a viscosity-enhancing hydrocolloid, i.e., xanthan gum. The results show that the gel strength increases exponentially with xanthan concentration, thus suggesting a synergistic interaction between the two networks. We also study the effect of sucrose on the thermal and mechanical properties of modified gels, finding a marked increase in transition temperatures and gel elasticity. In recent years, three-dimensional (3D) food printing has been extensively studied in the food industry, due to its many advantages, such as customized food design, personalized nutrition, simplified supply chain, and the expansion of available food materials. In view of this growing interest for additive manufacturing, we also study the printability of the complete formulation composed of κ-carrageenan, xanthan gum and sucrose.

Gelatin gels are known to be nonequilibrium systems, because of the continuous growth and rearrangements of physical junctions, even in the solidlike state. Establishing a relationship between the relative degree of cross-linking and macroscopic elasticity would be crucial in understanding, modeling, and predicting the transformation processes of gelatin solutions. Performing rheological experiments on a distinct gel structure, with a definite number of cross-links, is, however, a challenging task. In isothermal conditions, indeed, the density of physical cross-links changes indefinitely, and network evolution cannot be arrested. Inspired by the inverse quenching technique applied in the past to semicrystalline polymers, we here apply an unusual thermal history to an aqueous solution of gelatin in the semiconcentrated regime (6.67%w pig-skin gelatin), in order to freeze the system in a metastable condition for a time sufficiently long to perform a rheological characterization. The solution, initially kept in the sol state at 60°C, is rapidly cooled below gelation temperature, and isothermal gelation is started at 10°C. After soaking at this low temperature for a given time, the sample is rapidly heated (inverse quenching) up to a value in the range 24–29 °C, where kinetics is monitored. If the waiting time at low temperature and the inverse quenching temperature are suitably chosen, sample elasticity will remain stationary for a relatively large time window, and rheological experiments can then be reliably performed.