β-glucosidase is an enzyme important to flavour enhancement. It hydrolyzes glucosides to release aglycones—aroma precursors that are bound to a sugar molecule—thereby making them available to contribute to the flavour of foods and beverages. While there is strong interest within the food and beverage industry to optimizing flavour through the use of exogenous and endogenous glucosidase in production, little is known regarding the possible occurrence of these enzymes within the human oral cavity. This could be an important source of flavour release and/or account for some differences between individuals in flavour perception. In the present study, we determined whether β-glucosidase is present in human saliva. First, an existing spectrophotometric assay that uses p-nitrophenyl-β-O- D -glucopyranoside as a substrate was modified and optimized for use in human saliva. The following variables were evaluated and where necessary, optimized: linearity of the assay signal, possible matrix interference, the effect of heat inactivation of the saliva, absorbance wavelength maxima, substrate saturation concentration, maximum saliva volume and the inclusion of α-cyclodextrin. The modified assay was then used to screen for β-glucosidase activity in the saliva of 20 individuals. Of the 20 samples analyzed, four were tentatively identified as containing active β-glucosidase and were further investigated.

Background: The purpose of the present study was to examine the efficacy of targeting inflammation as a means of improving mood following spinal cord injury (SCI) and explore the potential mechanisms of action. Methods: The study was a randomized, parallel-group, controlled, clinical trial (NCT02099890) whereby 20 participants with varying levels and severities of SCI were randomized (3:2) to either the treatment group, consisting of a 12-week anti-inflammatory diet, or control group. Outcome measures were assessed at baseline, 1 and 3 months, and consisted of CES-D scores of depression, markers of inflammation as assessed by various pro- and anti-inflammatory cytokines and several amino acids related to depression. Results: A significant group × time interaction was found for CES-D (Center for Epidemiologic studies Depression Scale) score ( p = 0.01), the TRP/LNAA (tryptophan/large neutral amino acid) ratio ( p = 0.04), the composite score of pro-inflammatory cytokines ( p = 0.04), IL-1 β (interleukin-1 beta) ( p = 0.04), and IFN- γ (interferon gamma) ( p = 0.03). Pearson ’ s r correlation showed significance between the Δ IL-1 β and both the Δ CES-D score ( r = 0.740, p < 0.01) and the Δ KYN/TRP (kynurenine/tryptophan) ratio ( r = 0.536, p = 0.02). The Δ KYN/TRP ratio was also significantly correlated with the Δ CES-D score ( r = 0.586, p = 0.01). Mediation analysis showed that the relationship between the Δ KYN/TRP ratio and the Δ CES-D score was mediated by the Δ IL-1 β . Subgroup analysis showed that participants with high CES-D scores had significantly higher concentrations of IL-1 β , and all correlations were maintained or strengthened within this subgroup. Conclusions: Overall, the results demonstrated the effectiveness of targeting inflammation as a means of improving mood in SCI, with potential mechanisms relating to the reduction in IL-1 β and improvements in levels of neuroactive compounds related to the kynurenine pathway. Due to the limited sample size, results should be interpreted with caution; however, they are worthy of further examination due to the potential impact of inflammation on depression