This study was carried out to measure the quality characteristics and antioxidant activity of yogurt supplemented with black rice flour (BRF), which has been known as food additives containing lots of anthocyanins as well as vitamins, minerals, and dietary fibers. The yogurt was prepared using starter culture containing Lactobacillus paracasei and Lactobacillus rhamnosus and was fermented at 37°C for 12 hrs. Black rice flour (BRF) was added to yogurt mix before fermentation with different concentrations, 0% (control), 1% (BRF-1), 2% (BRF-2) and 3% (BRF-3) of total volume. The viable cell count (log CFU/g) of lactic acid bacteria (LAB) was measured by MRS broth at 0, 3, 6, 9 and 12 hr during fermentation as well as pH and titratable acidity (TA). Total antioxidant activity of the yogurts were evaluated by FRAP assay and measuring DPPH and ABTS radical scavenging activities. The viable cell counts of LAB in yogurt supplemented with BRF significantly increased compared to control. There was significant difference among 1%, 2% and 3% BRF added yogurts on growth rate of LAB (p&lt;0.05). The pH decreased significantly faster in yogurt supplemented with BRF, and also the TA increased significantly faster in yogurt supplemented with BRF compared to control. As results of the antioxidant activity of yogurt supplemented with black rice flour, BRF-3 displayed the highest DPPH and ABTS radical scavenging activity as well as FRAP activity (p&lt;0.05). The antioxidant activities of yogurt were influenced by the BRF addition. These results indicate that the addition of black rice flour to yogurt is effective in increasing LAB growth rate during fermentation and antioxidant activities. Therefore, it is considered that the yogurt supplemented with black rice flour is able to develop a functional dairy product.

Effect of black rice on quality characteristics and antioxidant activity of yogurt fermented using Lactobacillus paracasei and Lactobacillus rhamnosus

253rd National Meeting (2017)

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