*3.2. Biofunctional Characteristics*

The thermophilic counts are "components" of yoghurts with biological value and along with particular substances such as proteins, peptides, vitamins, specific lipid compounds configure the biofunctionality of this type of fermented milks. Thermophilic bacilli and cocci log counts—estimated according to the ISO 7889-IDF 117 standard [34] - and the percentage of angiotensin converting enzyme inhibitory activity (ACE-IA)—often called anti-hypertensive potential- are shown in Table 5.

According to the results, both the enrichment and the treatment of the milk base did not affect the counts of *Lb. bulgaricus* and *Str. thermophilus*, which were high and very close to the suggested 1:1 ratio, after 10 days of storage. Of particular interest are the high numbers of bacilli which are considered very beneficial for the gastrointestinal system. The modern trend for yoghurts and fermented milks with mild characteristics has suppressed the presence and the viability of *Lactobacillus delbrueckii* subsp. *bulgaricus* in yoghurt starters to avoid the development of excessive acidity during storage. In our previous experiments carried out with commercial starters [1,7], we estimated less than four log cfu/g thermophilic bacilli whereas cocci counts were close to nine log cfu/g. Very low or even zero lactobacilli counts have also been estimated in market yoghurts [35]. Apparently, the biofunctional profile of the yoghurt-type gels of Table 5 is related to the Greek traditional sheep yoghurt used as a starter that contained 8.52 log cfu/g *Lb. bulgaricus* and 6.82 log cfu/g *Str. thermophilus*, while its ACE-IA was 57.5%.

ACE-IA in the present gels was high coinciding with the high bacilli counts and the high % ACE-IA of the starter. In our previous studies [1,7] the ACE-IA of the skim sheep milk set-style yoghurt ranged from 22% to 25%. In the present study, ACE-IA was not affected by the type of treatment and statistical differences were observed only between different mixtures of the HT-group. In general, the enrichment of dairy products with whey-derived peptides is expected to "add" biofunctional ACE-I peptides [36]. Nevertheless, in the present experiments the supplementation of the skim milk base decrease slightly this activity, indicating the importance of the viable counts for this category of dairy products.


**Table5.**Biofunctionalcharacteristicsofyoghurt-typegelsmadefromskimsheepmilkbasesenrichedwithWPHsaftertendaysof

*Lactobacillus delbrueckii* subsp. *bulgaricus* [34]; 4 *Streptococcus thermophilus* [34]; 5 two-way ANOVA. a–b, lowercase letters indicate statistically significant differences (LSD, *p* < 0.05) withineachtypeoftreatment,i.e.,withinrows;A–B,indicatesignificantdifferences(*<sup>p</sup>*<0.05)betweenHTandHPtreatments.
