RESUMEN
In this study, we examined in vitro the bio-activity of peptide fractions obtained from soybeans against blood (CCRF-CEM and Kasumi-3), breast (MCF-7), and prostate (PC-3) cancer cell proliferation. Gastro-intestinal treated peptide fractions (<5, 5-10 and 10-50 kDa) prepared from seed proteins of two high oleic acid soybean lines-N98-4445A, S03-543CR and one high protein line-R95-1705, were tested for anticancer activity against human breast, blood and prostate cancer cell lines. Anti-proliferative cell titer assay was conducted to assess the inhibitory effects of the peptide fractions, while trypan blue dye exclusion assay was used to determine the dose response of most effective fractions. Results showed that the peptide fractions inhibited the cancer cell lines up to 68.0% and the minimum concentration to get 50% inhibitory activity (IC50) ranged between 608 and 678 µg/mL. This multiple site in vitro cancer inhibition by GI friendly peptides could have the potential use as food ingredients or nutritional supplements in an alternative cancer therapy.
RESUMEN
Soy proteins when prepared to high purity can confer good functional properties and the whey by-product is a potential source for bioactivity. In this study, we determined the protein, moisture, fiber, solubility, foaming, emulsion properties, as well as Angiotensin-I converting enzyme (ACE-I) inhibitory activity of prepared soy-whey proteins and its fractions. The soy-whey proteins were fractionated into <5, >5, >10, and >50kDa using ultrafiltration. The expanded AACC methods were used to determine protein, moisture, and fiber analyses of the whey and its fractions. Solubility method was conducted to determine the protein solubility profile of the soy-whey and its fractions at varying pHs. Turbidimetric method was used to evaluate emulsifying activity (EA) and emulsion stability (ES). There were significant differences observed in moisture, protein and salt contents between unfractionated, >50kDa and smaller sized fractions. No significant differences were observed with phytic acid and total dietary fiber contents among all samples. The unfractionated whey protein and >50kDa fraction showed better solubility than other fractions. Unfractionated whey protein had the highest foam capacity (42.7mL) while the fraction >5kDa showed the greatest foaming stability (46min). The highest emulsion activity (0.33±0.1) and stability (825.1±45.1) was obtained with the >50kDa fraction while the unfractionated whey protein had the highest ACE-I inhibition activity. The findings indicate that soy-whey protein fraction (>50kDa) had good solubility, emulsion activity and stability, while the unfractionated whey protein exhibited the strongest ACE-I inhibition percentage (19%).