Brown rice protein–dietary fibre conjugate improves bioaccessibility of minerals via modifying gelling structure of yoghurt

Abstract

SummaryThe present study aims to provide an overview of the impact of brown rice protein (BRP) conjugated with microcrystalline cellulose via the Maillard reaction on characteristic features of yoghurt and the bioaccessibility of essential minerals in this dairy product. The confirmation of conjugation was conducted using FTIR spectroscopy. Adding BRP or Maillard conjugate (MC) proved beneficial in enhancing the water‐holding capacity and decreasing the syneresis of samples. Additionally, yoghurt (MCY) containing the Maillard conjugate demonstrated superior performance in these properties. A lower number of pores and a stronger gel network (structural integrity) were identified in MCY compared to the other samples (BRPY: yoghurt containing BRP and PY: plain yoghurt). On the other hand, in general, supplementation of BRP and MC led to slight alteration in the concentration of aroma compounds. Similarly, the impact of BRP and MC on changes in the molecular weight distribution of proteins during in vitro gastrointestinal digestion was negligible. Bioaccessibility values of Ca and Mg in PY were 53.72% and 10.72%, respectively. The improvement in these values was observed in BRPY (Ca: 57.33% and Mg: 15.60%). Moreover, adding MC to yoghurt led to a tighter interface structure (indicating rigid gel), which allowed more minerals to bind, increasing mineral bioaccessibility (Ca: 64.40% and Mg: 31.14%). A higher general acceptability in sensory evaluation was scored for PY followed by MCY and BRPY. Ultimately, the positive effect of ingredients (especially MC) on yoghurt quality was obvious.