Correlations of Molecular Weights of β-Glucans from Qingke (Tibetan Hulless Barley) to Their Multiple Bioactivities

β-glucans have been considered the major bioactive components in Qingke (Tibetan hulless barley). However, the structure–function relationships of β-glucans from Qingke have seldom been investigated. Whether the bioactivities of Qingke β-glucans are closely correlated to their molecular weights remains unknown. Therefore, in order to explore Qingke β-glucans as functional/healthy food ingredients for industrial applications, and to better understand their structure–function relationships, correlations of molecular weights of Qingke β-glucans to their in vitro binding properties, inhibitory activities on digestive enzymes (α-amylase and pancreatic lipase), anti-inflammatory activities, and anticancer activities were systematically investigated. Results showed that the in vitro binding properties and the inhibitory activities on α-amylase and pancreatic lipase of Qingke β-glucans were positively correlated to their molecular weights. However, the anti-inflammatory activities of Qingke β-glucans increased as their molecular weights decreased. Furthermore, Qingke β-glucans exhibited selectively anti-cancer activities in vitro. Positive and negative correlations of molecular weights to inhibitory effects against A549 cells and MDA-MB-231 cells were observed, respectively. However, the inhibitory effects of Qingke β-glucans against HCT116 cells were not associated with their molecular weights. Results suggested that the molecular weights of Qingke β-glucans significantly affected their bioactivities, which was beneficial for a better understanding of their structure–function relationships. Moreover, results showed that Qingke β-glucans could be further explored as functional/healthy food ingredients for industrial applications due to their multiple health benefits