DEVELOPMENT OF FUNCTIONAL LOW-FAT YOGHURT FORTIFIED WITH PSYLLIUM HUSK MUCILAGE: QUALITY ATTRIBUTES, MICROSTRUCTURE, AND ANTIOXIDANT CHARACTERISTICS

Abstract

Background. Psyllium has a long history as a dietary supplement, since it is a rich source of both soluble and insoluble fibre that is reported as a traditional medicine in areas of India and China. Its consumption has been shown to provide nutritional benefits, Thus, interest in the incorporation of psyllium into food products is growing. This study was designed to assess how adding psyllium husk mucilage (PHM) at different concentrations impacts on the physical and quality characteristics of yoghurt during storage for 15 days at 5 ±1°C. Materials and methods. Three different concentrations [33.3 (low), 66.6 (medium), and 100 mg/100 g (high)] were used in low-fat yoghurt fortifications. Water-holding capacity, syneresis, pH, titratable acidity, total phenolic content (TPC), DPPH scavenging activity, flavour compounds, texture profile, and sensory properties of resultant yoghurt were analyzed. Results. The addition of PHM to low-fat yoghurts modified the acidification rate, fermentation time and significantly (p < 0.05) increased the viscosity, water-holding capacity, further improved the diacetyl concentration during storage. Total phenolic compounds and DPPH scavenging activity were significantly increased by the addition of PHM at a high dose (100 mg/100 g). Furthermore, low-fat yoghurt enriched with PHM had a compact and thick gel structure, together with a homogenous systematic protein aggregation network. Sensorially, low-fat yoghurt with 66.6 mg/100 g PHM revealed the highest sensory attributes score. Conclusion. Overall, PHM extract offers a promising choice as a natural stabilizer for a unique fibre-fortified yoghurt with nutritional value.