# Probiotics in Functional Foods: Survival Assessment and Approaches for Improved Viability
## 4 Limitations and Future Perspectives  
As many novel and alternative approaches have been employed to increase the shelf life of probiotics, many regulatory issues have been arising during storage conditions. Refrigeration is still an inevitable procedure that needs to be followed even after processing probiotics. Humid conditions cause degradation in the probiotic metabolically and texturally. Acid stress in citrus and foods with lower pH requires mandatory refrigeration to avoid deactivation and oxidation of the bioactive foods. Although many techniques arise to upgrade the shelf life of probiotics, the need to maintain ambient conditions makes the overall process very expensive and cumbersome [8]. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Techniques** & **Probiotic** & **Size Range** & **Shape** & **Conditions** & **Remarks** & **Efficiency of Encapsulation** & **References** \\ \hline \multirow{8}{*}{Freeze drying} & _L. plantarum_ & & & & & & \\  & _P. acillacti_ & & & & & & \\  & _Policoccus_ & & & & & & \\  & _protusocusus_ & & & & & & \\  & _S. bulardii_ & \textgreater{}1 mm & Irregular & Vacuum -0.5 & & & \\  & _L. acidophilus_ & & & & & & \\  & _L. casi_ & & & & & & \\  & _L. rhamnosus_ & & & & & & \\  & _P. acillacti_ & & & & & & \\  & _L. acidophilus_ & & & & & & \\  & _L. acidplandithiculallus_ & & & & & & \\  & _plantarum_ & & & & & & \\ Extrusion & _Lactiascibillus_ & & & & & & \\  & _parascal_ & 3 mm & Beaded & Gelling 0.25\% & & viability, & (approximate & [91; 92; 93; 94; 95; 96] \\  & _L. acidplandithiculallus_ & & & & & & \\  & _pentosus_ & & & & & & \\  & _L. casi_ & & & & & & \\  & _L. acidophilus_ & & & & & & \\  & _L. plantarum_ & & & & & & \\  & _L. casi_ & & & & & & \\ Emulsion & _Enterococcus_ & 2 mm & Spherical & controlled along with other general & High survival, & 84–97\% & \\  & _fecin_ & & & & & 1 mm capsules & (approximate & [97; 98; 99; 100; 101; 102] \\  & _S. bulardii_ & & & & other general & produced & maximum) & \\  & _L. saliverius_ & & & & reaction & & \\  & _Bifidobacterium_ & & & & & & \\  & _L. plantarum_ & & & & & & \\ Spray drying & _L. paracasi_ & 80 mm & Spherical & & & & \\  & _S. cerevisiae_ & & & & & & \\  & _S. cerevisiae_ & & & & & & \\  & & & & & & & \\  & & & & & & & \\ Refractance drying & _L. plantarum_ & Greater than & & & & & \\  & 1 mm & & & & & & \\  & _L. plantarum_ & & & & & & \\  & _B. lactis_ & & & & & & \\  & _L. gasseri_ & & & & & & \\  & _B.lidobacteria_ & & & & & & \\ Electrohydrodynamic & _L. rhamnosus_ & 150 nm & Fibers & Voltage and tip resistance & Reproducible & 90\% & \\  & _B. animals_ & & & & & fibers, good & (approximate & [90; 111; 112; 113; 114] \\  & _Iactis_ & BB12 & & & & & & \\  & _Stripococcus_ & & & & & & \\  & _thermophilus_ & & & & & & \\ Three-dimensional & & & & & & & \\ printing & & & & & & & \\  & & & & & & & \\  & & & & & & \\  & & & & & & \\ Microfluidics & gut bacteria & - & Droplet & Double emulsion & & & & \\  & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Recent techniques used to enhance viability of probiotics for commercial applications. The process of microencapsulation enhances and stabilizes sensory properties, as well as immobilizing cells to ensure uniform distribution of the product throughout the product's whole surface. There are a variety of elements that influence the efficiency of microencapsulation. When it comes to viability, the type of microencapsulation used by the method of spray drying, the intake and output temperatures, as well as the probiotic strains chosen, are all important considerations to consider in future prospects [12]. It is particularly important to choose the right wall material for the probiotics since they must be protected from oxygen, heat and other environmental challenges during drying, processing, and storage, as well as from low pH and protease in the gastric tract [12].