Impact of whole chia seeds (Salvia Hispanica) addition on the properties and stability of the set-type yogurt

Abstract

Natural plain yogurts enriched with 1, 2, and 3% of whole chia seeds (Y1, Y2, and Y3 respectively) were produced, in addition to a control yogurt (CY) without supplementation. The physicochemical parameters monitoring was conducted every week for a period of 4 weeks of cold storage (4°C) at the days 1, 7, 14, 21 and 28 (mentioned as D1, D7, D14, D21 and D28 respectively). The results showed that the pH values and titratable acidity didn’t fluctuate significantly between samples (P>0.05). The syneresis highest degree was observed for CY, which indicates a better capacity of retaining water for fortified yogurts. The total polyphenol contents increased significantly with increasing enrichment rates and ranged from 0.13±0.006 to 0.21±0.02 mg EAG/g for CY and Y3 respectively on D1. The antioxidant activity, estimated by DPPH and ABTS tests was significantly higher in enriched yogurts (from 24.1±1.66 to 49.4±2.11% of DPPH inhibition on D14 for CY and Y3 respectively). The viability of lactobacilli and streptococci was significantly enhanced in yogurts containing chia seeds compared to the control (P<0.05). The sensory analysis revealed that the chia seeds addition increased the intensity of smell, aroma, sweetness and consistency of yogurts and decreased their acidity. Y2 and Y3 samples were the most appreciated by the panelists.