3.3. Sensory evaluations
The sensory scores of the samples are given in Table 2.
The points allocated for colour, body-texture and taste
showed that an increase in sugar content brought about
an improvement in the structure, creaminess, flavour and
aroma of the products (p < 0.01). The addition of inulin
had no effect on sensory properties of probiotic ice-creams
(p > 0.05). A yogurt or probiotic flavour was not found to
be particularly noticeable. One reason for this could be the
high pH of the ice-cream. All the samples gave a good total
impression, were medium sour and did not have any
marked off-flavour during the storage period. None of
the ice-creams were judged to be crumbly, weak, fluffy or
sandy.
4. Conclusions
Effects of inulin and different sugar levels on physical
and sensory characteristics of probiotic ice-cream were
investigated. Increasing sugar concentration led to products
with better physical and sensory properties. The addition
of inulin improved viscosity, first dripping and
complete melting times, but had no effect on sensory properties
of the samples.
Survival of yogurt and probiotic bacteria was also
studied in probiotic ice-cream with different sugar concentrations
and with or without supplementary inulin during
90 days. Sugar concentrations significantly affected viable
bacteria numbers (p < 0.01). The highest number was in
the samples with 18% sugar. The survival of probiotic
bacteria was higher in the samples supplemented with inulin.
This could be due to prebiotic effects of this oligofructose.
S. thermophilus was most stable in all the samples of
probiotic ice-cream with >107 cfu g1 throughout the storage
period. The counts of L. delbrueckii ssp. bulgaricus
were reduced by 1.5 log cycles. The counts of L. acidophilus
and B. lactis decreased to 105 cfu g1 in the control
samples, whereas the counts were 106 cfu g1 in the samples
supplemented with inulin. The results suggested that
the addition of inulin stimulated the growth of L. acidophilus
and B. Lactis, which resulted in improved viability of
these organisms.