Another approach of testing health promoting properties of fruit
based acidity regulators relied on the assessment of biological potential
determined as capability of growth inhibition of HT29 cells
by “pH 3.5 MIX-es”. Similarly to common practice, it was assumed
that higher cytotoxicity marks greater concentration of biologically active components.
Fig. 3 presents the dose response curves for the “pH 3.5 MIX-es”
in HT29 cell line. In all cases, the prolonged exposure on plant juices
resulted in the stronger biological effect. The lowest cytotoxicity
exhibited the mixture containing citric acid, whose addition
reversed significantly growth inhibition induced by beetroot juice
alone i.e., the sample used as a reference in these experiments. This
may suggest that citric acid decreased biological potential of the
tested juice. Among “pH 3.5 MIX-es” acidified with fruit juices,
those containing lemon and blue-berried honeysuckle juices
exhibited the strongest ability to inhibit cell growth. This is not
suprising, since these fruit juices contain bioactive compounds that
are known to impose cytotoxic effect on cancer cells: lemon is the
rich source of flavonol glycosides, while blue-berried honeysuckle
flavan-3-ols and anthocyanins. Most probably betalains were not
phytochemicals responsible for cell growth inhibition because
these two mixtures did not contain the highest amounts of betalains
(Table 4). Cytotoxicity assessments again confirmed superiority
of fruit based acidity regulators over citric acid in terms of
bioactivity.
acidity regulator turned out to be the blue-berried honeysuckle
juice. Not only it displayed comparable ability to control pH as citric
acid, but also ensured the highest antioxidant activity of the final
mixtures. In the case of beetroot juice as a model food item, such a
combination exhibited the strongest cytotoxic effect against cancer
cells, but also gave the final food product an interesting flavor.
Moreover, blue-berried honeysuckle juice enriched the mixture in a
number of bioactive phytochemicals characterized by a range of
reported chemopreventive properties that may have a very positive
impact on consumers' health. The only drawback is the high cost of
blue-berried honeysuckle due to rather limited harvest and low
availability of this plant. Thus, the economic issues can restrict the
potential production of acidity regulators based on extracts from
this fruit. However, also very promising seemed sea buckthorn juice
and mirabelle plum juice. Both of these plants are known for their
positive impact on human health and in the presented experiments
exhibited very close capacity of controlling pH of food products to
citric acid. For economic reasons and because of the widespread
occurrence, a minor degree of current utilization, and apparent ease
of collection, mirabelle plum appears to be a replacement of current
acidity regulators particularly worthy of interest.