The effect of soy protein isolate and oat germ powder on some qualitative and textural characteristics of whey-less feta cheese

The effects of soy protein isolate (SPI) and oat germ powder (OGP) were investigated on some characteristics of whey-less cheese. In this study, 6 different treatments were prepared in which part of the combination of milk protein concentrate (MPC) and skim milk powder (SMP) were replaced with different ratios of SPI and OGP (0: 0, 6.7: 3.3, 5: 5, 10: 0, 0:10 and 3.3: 6.7%). The results showed that the moisture, protein content and acidity of the samples increased with increasing SPI about 8.8, 25.2 and 6.8% and decreased with increasing OGP about 1.9, 26 and 18.7% respectively. The addition of SPI and OGP, the phenolic compounds increased from 99.3 to 303.99 and 169.65 mg/100g respectively (p<0.05). With increasing SPI and OGP, the L* index decreased and the b* index increased. But the a* index increased with increasing OGP and decreased with increasing SPI (p<0.05). The hardness and gumminess in the control sample was the highest and the samples containing 10% SPI were the lowest. Cohesiveness and springiness of 5% SPI and 5% OGP mixed samples were the highest and samples containing 6.7% SPI and 3.3% OGP were the lowest. The gumminess and chewiness decreased with increasing SPI and increased with increasing OGP (p<0.05). With increasing SPI and OGP, the overall acceptance score of the samples decreased but was not significant (p>0.05). It was concluded that, the mixture of 5% SPI and 5% OGP or 3.3% SPI and 6.7% OGP could be used in production of whey-less cheese.