Does the taste of sugar replenish willpower? In a post titled Willpower Depletion vs Willpower Distraction the claim is made that:


  Basically, for a while some researchers believed that willpower
  depletion "is" glucose depletion in the prefrontal cortex, but some
  more recent experiments have failed to replicate this, e.g. by finding
  that the mere taste of sugar is enough to "replenish" willpower faster
  than the time it takes blood to move from the mouth to the brain:


Is that claim representative of the knowledge we have from studies?
I'm not sure what you mean to ask here, but there is a recent (2016) meta-analysis by Vadillio, Gold and Osman just on the topic of glucose and willpower. Abstract:


  The idea behind ego depletion is that willpower draws on a limited mental resource, so that engaging in an act of self-control impairs self-control in subsequent tasks. To present ego depletion as more than a convenient metaphor, some researchers have proposed that glucose is the limited resource that becomes depleted with self-control. However, there have been theoretical challenges to the proposed glucose mechanism, and the experiments that have tested it have found mixed results. We used a new meta-analytic tool, p-curve analysis, to examine the reliability of the evidence from these experiments. We found that the effect sizes reported in this literature are possibly influenced by publication or reporting bias and that, even within studies yielding significant results, the evidential value of this research is weak. In light of these results, and pending further evidence, researchers and policymakers should refrain from drawing any conclusions about the role of glucose in self-control.


It's not too far in its conclusions from a 2014 meta-analysis on the mere existence of ego/willpower depletion. 

As Vadillo et al. use p-curves, the interpretation of their result is somewhat subjective.



Here is their interpretation:


  The results of our analyses suggest that the relationship
  between glucose levels and self-control behaviors might
  be unreliable. Figure 1 shows that the key p values of the
  19 studies included in the present analyses follow a surprisingly
  flat distribution. This is exactly the pattern of
  results that one would expect to find if those results were
  false positives. These results remain unchanged regardless
  of whether glucose-rinsing studies are included or
  excluded from the sample.
  These results may not come as a complete surprise
  given the empirical challenges to the glucose hypothesis
  suggested by failed replications (Job et al., 2013; Kelly
  et al., 2015; Lange &amp; Eggert, 2014; Lange et al., 2014) and
  theoretical critiques regarding its biological plausibility
  (Kurzban, 2010; Osman, 2014). Furthermore, a detailed
  analysis of the seminal article suggesting the glucose
  hypothesis showed that the number of significant findings
  reported in that article was too large, given the low
  power of each study (Schimmack, 2012). In other words,
  the results were too good to be true (Francis, 2012).
  Nevertheless, the findings from the present study are a
  surprise in the context of the wide acceptance of the
  glucose hypothesis in general scientific research and its
  popularity, as evidenced by the number of citations of
  Gailliot et al. (2007) in the literature and the continued
  influence of this hypothesis in recent reviews on ego
  depletion (e.g., Baumeister, 2014; Baumeister &amp; Alghamdi,
  2015).
  
  [...]
  
  It is worth noting that, as with any other statistical test,
  p-curve analysis is not a flawless indicator of bias (Bishop
  &amp; Thompson, 2016; Bruns &amp; Ioannidis, 2016; Lakens,
  2015). Our results suggest that, on average, these studies
  have little or no evidential value, but they do not allow
  us to determine whether the significant results are due to
  publication bias, selective reporting of outcomes or analyses,
  p-hacking, or all of these. It is not impossible that
  some of these studies are exploring small but true effects
  and that their evidential value may be diluted by the
  biases that pervade the rest of the studies. Perhaps future
  research will show that glucose does play a role in egodepletion
  effects, but our conclusions are based on the
  analysis of the extant literature in this area. Thus, our
  contribution must be seen as an additional piece of information
  in the wider context of attempts to verify the reliability
  of the glucose model of ego depletion. Note that
  the kind of biases explored in the present study are prevalent
  in other (but not all) areas of psychological research
  (e.g., Bakker, van Dijk, &amp; Wicherts, 2012) and that low
  reproducibility is not exclusively a problem of psychological
  research (Camerer et al., 2016; Errington et al.,
  2014). 




The meta-analysis had a special category for glucose-rinsing studies:


  Glucose-rinsing studies examine the impact of simply
  rinsing one’s mouth with a glucose solution
  before exerting self-control (Hagger &amp; Chatzisarantis,
  2013; Lange &amp; Eggert, 2014; Molden et al., 2012;
  Sanders, Shirk, Burgin, &amp; Martin, 2012). Results
  from these studies suggest that the signal of glucose
  from the mouth to the brain is sufficient to
  neutralize the ego-depletion effect. This mechanism
  is consistent with the results of the ingestion
  manipulations but suggests that the effect does not
  depend on a metabolic explanation.


Here's the full table of studies included, which included an indicator column for whether the study was rinsing-only:



But there's no separate p-curve just for the rinsing studies. You can probably make one yourself though...

Actually I just did that with the 8 studies in the "yes" column:




Note that they've changed the test somewhat since that meta-analysis was published.

The meta-analysis did note that whether the rinsing studies were added or removed made no difference on the p-curve testing of the rest. And from my graph you can kinda see why: ignoring the 0% bins, the rinse group has roughly the same shape as the whole group.