PASSION FRUIT PULP: CHARACTERIZATION OF BIOATIVE COMPOUNDS AND APPLICATION IN POTENTIALLY PROBIOTIC FERMENTED MILK

Fermented milk (FM) products are considered food with functional properties and a great vehicle for probiotics. The addition of fruit pulp has been a tendency to increase the consumption of FM. Fruit pulp confers pleasant properties to these products and simultaneously, increases their nutritional value and healthy appeal, since many fruits contain in their composition bioactive compounds, which may help to reduce the incidence of certain diseases. The objective of this study was to characterize the passion fruit pulp (PFP), and to apply it in FM. PFP was characterized regarding chemical composition, fatty acids profile, total phenolic compounds content, yellow flavonoids and anthocyanins, β-carotene, lycopene and antioxidant activity (AA). For FM preparation, two treatments were performed: FMPFP, FM with 1% PFP (w/v), and FMWP, FM without pulp. The fermentation was performed by the potentially probiotic bacteria, Lactobacillus casei SJRP38 (8 log CFU/mL), and Streptococcus thermophilus ST080 (6 log CFU/mL). The kinetic parameters of fermentation, viability of L. casei, acidity, water holding capacity (WHC) and syneresis during the refrigerated storage period (1, 14 and 28 days) were carried out. PFP presented 4.09 % moisture and 1.50% lipid contents, and the main fatty acids were palmitic acid and α-linolenic acid (omega-3) (0.37 g/100 g and 0.4 g/100 g of lipid, respectively), which have beneficial effects on the consumers’ health and are related to the prevention of certain diseases. Additionally, PFP presented 220.99 ± 0.10 EAG/100 g of phenolic compounds and 87.99 ± 0.04 µg/g β-carotene, and 2.87 ± 0.05 μmol Trolox/g of AA, whereas lycopene, yellow flavonoids and anthocyanins contents were low (48.22 ± 0.03 µg/g, 4.33 ± 0.05 mg/100 g and 0.15 ± 0.01 mg/100 g, respectively). The AA is directly related to the amount of phenolic compounds, vitamins, carotenoids that are present in the fruits. The addition of PFP decreases the maximum acidification rate (Vmax) of FM, and the fermentation time of FMPFP (12.29 ± 1.95 10−3 upH/min) was lower than FMWP (21.54 ± 1.97 10−3 upH/min). Composition of both treatments differed slightly (p ≤ 0.05) in moisture content, however, these variations are considered acceptable in industrial processes. The acidity and WHC increased over the storage time in both treatments (p ≤ 0.05), while the syneresis was stable. The phenolic compounds content in FMPFP was 54.37 ± 0.90 EAG/100 g, which is proportional to that found in PFP; however, there was a reduction during the storage (p ≤ 0.05), since some microorganisms degrade some polyphenols to use them as an energy source. The AA in both FMPFP and FMWP remained constant throughout the storage period (p ≥ 0.05). L. casei and S. thermophilus presented high viability and remained stable during the storage period (> 11 log CFU/mL; > 6 log CFU/mL, respectively). In conclusion, PFP presented several bioactive compounds, such as unsaturated fatty acids, phenolic compounds, carotenoids and AA. The addition of PFP to FM production increased its functional potential and consequently, the possibility of providing beneficial health effects, due to the content of β-carotene, phenolic compounds and AA.