Quality characteristics and antioxidant activity of goat milk yoghurt fortified with Lycium ruthenicum Murr. fruit

This study aimed to analyse the influence of adding Lycium ruthenicum Murr. fruit (LRF) on physicochemical, sensory characteristics and antioxidant capacity in goat milk yoghurt (GMY) during 21 days of refrigerated storage. Three different yoghurt formulations were processed using varying amounts of added LRF (1.0, 1.5, and 2.0%). LRF supplementation improved some of the physicochemical characteristics and sensory characteristics of GMY. With the increase of LRF addition, the pH of GMY showed a downward trend, and the titrated acidity showed an upward trend. The corresponding number of colonies in the storage period was higher than that of yoghurt without LRF. The addition of a concentration of 1.0–2.0% LRF played a role in the proliferation of lactic acid bacteria, and viscosity and hardness increased with increasing LRF addition. Although the susceptibility to syneresis of GMY showed a downward trend with increasing LRF addition, the scavenging rate of DPPH (2,2-diphenyl-1-picrylhydrazyl), •OH (hydroxyl free radicals), and the reducing power of Fe³⁺ of the corresponding concentration of GMY increased. In general, GMY with LRF addition can combine the two nutrients and have higher nutritional value, which is a good supplement to the same types of products in the market.