This study investigated the stability of Lactobacillus rhamnosus GG (LGG) in cocoa juice. Lactobacillus rhamnosus GG was encapsulated separately with sodium alginate and sodium alginate+gum Arabic, and incorporated into cocoa pulp juice. Un-encapsulated LGG (free cell) served as a control. The viability of free and encapsulated LGG in cocoa juice and simulated gastrointestinal conditions was evaluated. The juice was stored at 4 ?C for 28 days and its chemical composition was determined weekly. Colour attributes and sensory properties of the freshly prepared juice were also determined. The percentage yield of LGG encapsulated with sodium alginate and sodium alginate+gum Arabic was 80.8 and 89.9%, respectively. Sodium alginate+gum Arabic encapsulated LGG showed higher viability in cocoa juice and simulated gastrointestinal conditions than free cell and LGG encapsulated with sodium alginate only. There was no significant (p>0.05) difference in the pH of cocoa juice that contained sodium alginate only (CJSA) and the one that contained sodium alginate+gum Arabic (CJAG). Titratable acidity of CJAG was significantly (p<0.05) higher than CJSA throughout the storage. Significantly higher pH, total soluble solids, and sugar were recorded for cocoa juice that contained the free cell (CJFC) compared to CJSA and CJAG. There was no significant (p>0.05) difference between CJSA and CJAG in terms of the degree of lightness, however, the samples differed significantly (p<0.05) in terms of chroma, and colour intensity. There was no significant (p>0.05) difference between CJFC and CJAG in terms of colour, appearance, aroma, taste, and consistency. This study showed that the encapsulation of LGG with sodium alginate and gum Arabic improved its stability in cocoa juice.

This study investigated the effect of pretreatment of orange and plantain peels on the inactivation kinetics and thermodynamic properties of polygalacturonase (PG) produced by Aspergillus awamori CICC 2040. Orange and plantain peel powders were subjected to microwave-assisted NaOH pretreatment and used as substrates for PG production. Un-treated peels served as controls. The PG was purified using acetone precipitation and column chromatography, and the inactivation kinetics, temperature dependency, and thermodynamic properties of the crude and purified PGs were determined. Higher inactivation rate constant was obtained for crude PG produced using pretreated orange peel (CPOF) and plantain peel (CPPF) compared to PG produced using untreated orange peel (Uo) and plantain peel (Up). At all the temperatures considered, higher half-life and decimal reduction time were recorded for CPOF and CPPF compared to Uo and Up. The highest half-life (45.60 min) and decimal reduction time (151.49 min) were recorded for CPOF at 60 ?C. Lower half-life and decimal reduction time were obtained for purified PGs compared to the crude PG. Polygalacturonase produced from pretreated peels had lower activation energy than those produced from untreated ones. The higher activation energy was recorded for the PG produced using orange peel compared to the one from plantain peels. The enthalpy of CPOF and CPPF was slightly lower than Uo and Up. The pretreatment of the peels resulted in a reduction of Gibbs free energy (?G ) and entropy (?S) of crude and purified PG. Higher ?G and ?S were recorded for the purified PG compared to the crude PG. Negative entropy and enthalpy were recorded for all the PGs. The findings from this study showed that the kinetic and thermodynamic properties of PG, produced by Aspergillus awamori CICC 2040, were enhanced by the pretreatment of orange and plantain peels.